JP2013061310A - Method and device for diagnosing soundness in transformer - Google Patents

Abstract

It is possible to determine whether or not a transformer winding is disconnected and whether or not there is a rare short in a short time with little effort.
A transfer function of a secondary winding in a frequency band where a first resonance of a transfer function when the winding is normal appears, and an input voltage applied to the secondary winding with the primary winding open. It is calculated from the detected output voltage (S1, S2), and when the value of the transfer function is less than the first threshold value, it is determined that a disconnection has occurred in the primary winding (S3: Yes). If it is equal to or greater than the second threshold value, it is determined that a short-circuit between turns or a short-circuit has occurred in the primary winding (S4: Yes). In other cases (S3: No and S4: No) The primary winding is determined to be normal (S5).
[Selection] Figure 1

Description

  The present invention relates to a transformer health diagnostic method and a health diagnostic apparatus. More specifically, the present invention relates to a technique suitable for use in determining whether or not a winding is disconnected in a transformer and whether or not there is a rare short.

  As a conventional method for determining the presence or absence of a rare short in a distribution pole transformer, for example, an alternating voltage having a different frequency is sequentially applied to the windings of the transformer, and the exciting current of the transformer with respect to the alternating voltage having a different frequency is used. A first-order differentiation is performed on the approximate curve of the measured excitation current value. When the differential value is positive, it is determined that there is no short circuit, and when the differential value is negative, it is determined that there is a short circuit (Patent Document 1). ). Note that the layer of the winding wound around the iron core of the transformer is referred to as a layer, and a state where the layers are short-circuited is referred to as a rare short or an interlayer short-circuit of the winding.

  Further, there is a frequency response analysis (FRA) as a method for diagnosing abnormality of a transformer winding. In frequency response analysis, a sine wave electrical signal (eg, voltage) is input and the amplitude of the output signal (eg, current) is measured while changing the frequency from several tens [Hz] to several [MHz]. The transfer function is obtained from the ratio of input to output. Here, the transfer function indicates resonance due to electrical constants such as leakage inductance, ground capacitance, and interwinding capacitance. If there is an abnormality in the transformer winding, these electrical constants change and the transfer function changes. To do. In the frequency response analysis, an abnormality of the transformer winding is diagnosed based on whether or not there is a change in comparison with a transfer function measured when the transformer is in a healthy state (that is, normal).

JP2009-14528

  However, the method for determining the presence or absence of rare short in Patent Document 1 requires a device for measuring current by sweeping the frequency over a wide range of 300 to 2000 [Hz] and several hundred points (that is, several hundred frequencies). Measurement is required, and there is a problem that it takes a lot of labor and time as well as equipment and equipment costs. In particular, since a very large number of distribution pole transformers are installed, the method of determining whether or not the rare short circuit is disclosed in Patent Document 1 is not highly versatile when the distribution pole transformer is targeted for diagnosis. .

  Further, in the frequency response analysis, it is necessary to perform measurement by changing the frequency from several tens [Hz] to several [MHz], which requires equipment / equipment costs and a great deal of labor and time. In fact, frequency response analysis is applied exclusively to transformers larger than the distribution / transformation class, and there is no application example to distribution pole transformers with a very large number of installations.

  If the transformer winding is disconnected, the transformer cannot be used in the first place regardless of the presence or absence of a rare short. The ability to confirm that the soundness is maintained is also important in the soundness diagnosis of the transformer. However, the method for determining the presence or absence of a rare short in Patent Document 1 does not have a function for confirming the continuity of the winding of the transformer. There is a problem that the presence or absence of disconnection cannot be determined.

  Accordingly, an object of the present invention is to provide a transformer soundness diagnosis method and a soundness diagnosis device that can determine whether or not a transformer winding is disconnected and whether or not a short-circuit occurs in a short time with little effort. And

  The inventors have studied the transformer health diagnosis method that can be carried out in a short time with little effort, and by measuring the transfer function of the transformer at a specific single frequency, the wire breakage of the winding It has been determined that it is possible to determine whether or not there is a rare short and whether or not there is a rare short. A test for verifying the validity of this technical idea unique to the present invention (hereinafter referred to as a verification test) will be described below.

ただし、ｊ：虚数単位，
ω：角周波数 をそれぞれ表す。 (1) Verification of determination method of presence or absence of rare short of transformer The transfer function measured in the frequency response analysis can be arbitrarily selected from winding impedance, admittance, voltage ratio, etc. in principle. In the verification test, as shown in FIG. 3, the input voltage Vin (jω) applied to the winding and the output voltage Vout (jω) based on 50Ω impedance are measured, and the input / output when an electrical signal is given. A transfer function H (jω) defined by Equation 1 that is the ratio of In FIG. 3, reference numeral 1 denotes a pole transformer, reference numeral 2A denotes a primary winding, reference numeral 2B denotes a secondary winding, and reference numeral 5 denotes a measuring device.

Where j: imaginary unit,
ω: represents angular frequency.

  In this verification test, the input voltage is applied to the secondary winding 2B with nothing connected between the terminals of the primary winding 2A and the output voltage is detected to calculate the transfer function (measurement) (hereinafter, open) Called measurement).

  First, FIG. 4 shows an example of a measurement result of a transfer function of a healthy (that is, normal) pole transformer by measurement under the above-described conditions (solid line A in the figure). As indicated by the solid line A in FIG. 4, the transfer function of the transformer appears as a curve having a downward convex portion in a region where the value is negative. The transfer function shown in FIG. 4 is for a pole transformer with a rated capacity of 50 [kVA], and the measurement frequency is up to 100 [kHz].

  Here, the resonance of the transfer function having the lowest frequency is called the first resonance, the frequency at that time is called the first resonance frequency, and the value of the transfer function is greatly increased or decreased as the first resonance appears. The frequency band is called the first resonance frequency band. Then, from the measurement result of the transfer function when the transformer is normal (solid line indicated by symbol A in FIG. 4), the first resonance frequency when this transformer is normal is approximately 200 to 300 [Hz]. It is confirmed that the first resonance frequency band is approximately 10 to 1000 [Hz].

  Next, the transfer function is measured after simulating a rare short with the same pole transformer as above. Here, the winding structure of the pole transformer used in this verification test is shown in FIG.

The rare of the primary winding 2 </ b> A is wound on each of the left and right sides of the iron core 4, for a total of 24. The number of turns of each rare is 150 times for each of the left and right rares closest to the tap board 3, and all other rares are 234 times. In addition, the rare of the secondary winding 2B is wound on each of the left and right sides of the iron core 4, and the total number is four. Each rare has 21 turns. The rare of the secondary winding 2B has a structure in which the left rare of the iron core 4 is connected to the right rare and the right rare is connected to the left rare. Then, pull out the upper winding of each rare and connect it above the oil level of the pole transformer to provide terminals (H _L2,3 ^{+ to} H _L12 ⁺ , H _L2,3 ^{− to} H _L12 ⁻ ) Simulate rare shorts by short-circuiting.

  The measurement result of the transfer function of the pole transformer when the primary winding rares are short-circuited is shown in FIG. 4 (solid line B in the figure). Then, from the measurement result of the transfer function in the rare short (simulated) state (solid line B in FIG. 4), the first resonance seen in the vicinity of several hundreds [Hz] when the transformer is normal disappears, It is confirmed that the value of the transfer function in the first resonance frequency band is 0 [dB].

  Further, the transfer function is measured after short-circuiting adjacent turns near the lead-out portion of the primary winding of the same pole transformer as described above. The short circuit between turns is regarded as the case where the degree of the short circuit is the smallest. In the present invention, the short circuit is included in the rare short circuit that can be determined by the transformer health diagnosis method of the present invention as one of the abnormality of the transformer.

  It is confirmed that when the turn of the primary winding is short-circuited, the value of the transfer function in the first resonance frequency band is about −5 [dB]. This value is larger than the value of the normal transfer function in the first resonance frequency band as compared with the measurement result of the transfer function when the transformer is normal (solid line indicated by the symbol A in FIG. 4).

  Based on the results of the above verification test, the presence or absence of wire breakage in the transformer based on the value of the transfer function in the first resonance frequency band (that is, the ratio of input and output when an electrical signal is given to the transformer) In addition, it is possible to determine the occurrence of short circuit between turns or rare short circuit. By measuring the transfer function of the transformer at the frequency of only one specific point, it is possible to determine the occurrence of wire breakage and short circuit between turns. The validity of the technical idea peculiar to the present invention for determining whether or not a rare short has occurred is confirmed.

  Although this verification test targets distribution pole transformers, the knowledge gained from this verification test is to determine the occurrence of wire breakage in the transformer and the presence or absence of short-to-turn shorts or rare shorts. The above technical idea is also applicable to other types of transformers.

  In addition, from the result of the verification test, it is confirmed that the first resonance frequency band of the distribution pole transformer is about 10 to 1000 [Hz], and there is a short circuit between turns or a rare short in the winding. It is confirmed that the value of the transfer function is approximately -5 to 0 [dB].

(2) Verification of the method for judging whether or not the transformer winding is broken The absolute value of the minimum value in the first resonance of the normal transformer transfer function decreases as the rated capacity of the transformer increases. Even if the capacity is the same, it differs depending on the type of transformer (substantially the characteristics of the iron core of the transformer). Further, the resonance frequency and the minimum value also change depending on the residual magnetic flux of the iron core. Table 1 shows an example of the minimum value of the normal transfer function and the measurement frequency at that time for pole transformers of various rated capacities and types.

From the organization results shown in Table 1, the following is confirmed.
i) The smaller the rated capacity of the transformer, the smaller the minimum value of the transfer function when it is normal (in other words, the larger the value swings to the minus side).
ii) In the results shown in Table 1, the minimum value of the transfer function when the transformer is normal is -35.5 [dB], and the transfer function when the transformer is normal even with various rated capacity / type transformers. The minimum value falls within the range of -10 to -40 [dB].
iii) The measurement frequency when the transfer function when the transformer is normal is at a minimum is in the range of 200 to 1000 [Hz].

  Here, if the transformer winding is disconnected, the value of the transfer function greatly fluctuates to the minus side to the full measurable range regardless of the magnitude of the measurement frequency. Therefore, when the value of the transfer function is smaller than −40 [dB] at an arbitrary measurement frequency, it can be determined that a disconnection has occurred in the winding of the transformer. Strictly speaking, when the value of the transfer function is smaller than −40 [dB], there may be a connection failure of the connection terminal or the lead wire at the time of measurement, but in that case, the connection state is confirmed and if necessary Considering the assumption that the measurement is performed again, if the value of the transfer function is smaller than −40 [dB], it can be determined that the transformer winding is disconnected.

(3) Verification of the magnitude of the input voltage applied to the transformer In the measurement shown in Table 1, the transfer function of the transformer during normal operation is measured with the input voltage applied to the transformer set to 5 [V]. Yes.

Table 2 shows the degree of fluctuation in the value of the normal transfer function of the transformer when the input voltage for measurement is changed, according to the rated capacity of the transformer. Table 2 shows the value of the transfer function when the input voltage (measured voltage) is 5 [V] and the value of the transfer function when the magnitude of the input voltage (measured voltage) is changed according to the rated capacity of the transformer. Organizing the differences. The measurement frequency of the transfer function is 200 [Hz].

From the comparative arrangement shown in Table 2, the following is confirmed.
i) When the input voltage (measured voltage) is small, the excitation becomes insufficient when the rated capacity of the transformer is increased, and the difference is compared with the value of the transfer function when the input voltage (measured voltage) is 5 [V]. Becomes larger and a correct transfer function cannot be obtained. On the other hand, 5 [V] is not always required as the input voltage (measurement voltage).
ii) That is, it is necessary to select the magnitude of the input voltage (measurement voltage) according to the rated capacity of the transformer to be diagnosed.
iii) Specifically, if the input voltage (measurement voltage) is 3.5 [V] or more, it is possible to measure any transformer with a rated capacity.

  The present invention is based on the unique knowledge obtained by the above-described analysis and examination by the inventors. Specifically, the transformer health diagnosis method according to claim 1 is characterized in that the winding is normal. The transfer function of the secondary winding in the frequency band where the first resonance of the transfer function appears is calculated from the input voltage applied to the secondary winding with the primary winding open and the detected output voltage. If the value of the transfer function is less than the first threshold value, it is determined that a disconnection has occurred in the primary winding, and if it is greater than or equal to the second threshold value, the primary winding is short-circuited between turns. Alternatively, it is determined that a rare short has occurred, and in other cases, it is determined that the primary winding is normal.

  According to a sixth aspect of the present invention, the transformer health diagnosis apparatus applies the input voltage to the secondary winding while the primary winding is open and detects the output voltage, and the winding is normal. When the transfer function of the secondary winding in the frequency band where the first resonance of the transfer function appears is calculated from the input voltage and the output voltage, and the value of the transfer function is less than the first threshold, It is determined that a break has occurred in the winding, and if it is greater than or equal to the second threshold, it is determined that a short-circuit between turns or a rare short has occurred in the primary winding, and in other cases the primary The winding has means for determining that the winding is normal.

  Therefore, according to the soundness diagnosis method and soundness diagnosis device of these transformers, paying attention to the characteristic of the transfer function value obtained as the original knowledge of the present inventors, the disconnection of the winding with respect to the value of the transfer function By using the first threshold value for determining whether or not the occurrence of a short circuit and the second threshold value for determining whether or not a short circuit between turns or a rare short circuit has occurred, it is possible to prevent the winding from being broken as a problem in the transformer. The occurrence / non-occurrence and the presence / absence of a short circuit / rare short between turns are determined. Furthermore, by setting the two threshold values in this manner, the occurrence of winding disconnection and the occurrence of rare short-circuit are clearly distinguished and determined.

  And, according to the soundness diagnosis method and soundness diagnosis device of these transformers, since the above-mentioned determination can be made based on the value of the transfer function at a specific frequency, the frequency over a certain range. The soundness of the transformer is determined without taking the trouble of sweeping.

  In addition, according to the soundness diagnosis method and soundness diagnosis device of these transformers, the above-described determination can be made based on the value of the transfer function obtained by a single measurement at a specific frequency. Therefore, it does not take time and effort to sweep the frequency over a certain range, and the presence or absence of occurrence of wire breakage by applying the input voltage and detecting the output voltage (in other words, measuring the transfer function) only once. And the soundness of the transformer is determined by determining whether or not a short-circuit between turns and a rare short have occurred.

  In addition, according to the soundness diagnosis method and soundness diagnosis device of these transformers, the soundness of the transformer is determined without opening and closing the upper cover of the transformer.

  According to a second aspect of the present invention, in the method for diagnosing a transformer health according to the first aspect, the frequency band in which the first resonance of the transfer function appears when the winding is normal is 10 to 1000 [Hz]. The transfer function of the secondary winding is calculated in the frequency band of 10 to 1000 [Hz]. Further, in the transformer health diagnosis device according to claim 6, the frequency band in which the first resonance of the transfer function appears when the winding is normal is 10 to 1000 [Hz]. Yes, the transfer function of the secondary winding is calculated in the frequency band of 10 to 1000 [Hz]. In these cases, since a transfer function is calculated in the first resonance frequency band at least for a transformer having a rated capacity of about 5 to 100 [kVA], particularly a rare short circuit occurs with respect to the transformer having the rated capacity. Presence / absence is appropriately determined.

  According to a third aspect of the present invention, in the method for diagnosing a transformer health according to the first aspect, the first threshold value is set to any value within a range of −50 to −40 [dB]. Yes. In the transformer health diagnosis apparatus according to claim 6, the first threshold value is any value within the range of −50 to −40 [dB]. Yes. In these cases, the first threshold value is set to a value lower than the minimum value of the normal transfer function in a transformer having a rated capacity of about 5 to 100 [kVA]. In particular, it is appropriately determined whether or not a winding breakage has occurred in a rated capacity transformer.

  According to a fourth aspect of the present invention, in the transformer health diagnostic method according to the first aspect, the second threshold value is set to any value within a range of -5 to 0 [dB]. . In the transformer health diagnosis apparatus according to claim 6, the second threshold value is any value within the range of -5 to 0 [dB]. . In these cases, the maximum value of the normal transfer function is lower than the value of the transfer function when the short-circuit between turns of the winding or the rare short occurs in the transformer having a rated capacity of about 5 to 100 [kVA]. Since the second threshold value is set to a value that exceeds the above value, it is determined appropriately whether or not a rare short circuit has occurred, particularly for the transformer having the rated capacity.

  According to a fifth aspect of the present invention, in the transformer health diagnostic method according to the first aspect, the input voltage is set to 3.5 to 5 [V]. According to a tenth aspect of the present invention, in the transformer health diagnostic device according to the sixth aspect, the input voltage is 3.5 to 5 [V]. In these cases, the input voltage to be applied for calculating the transfer function is minimized, so that the power supply mechanism can be composed of a small battery such as a dry cell, and the power supply mechanism is small. Is achieved. In these cases, the required level of withstand voltage characteristics can be kept low by reducing the input voltage to be applied, so that it is possible to avoid the use of expensive elements.

According to the transformer health diagnostic method and the health diagnostic device of the present invention, the first threshold value for determining the occurrence of wire breakage and the presence or absence of occurrence of a short circuit between turns or a rare short circuit are determined. Using the second threshold, it is possible to determine whether or not the transformer winding is broken and whether or not there is a short-to-turn short circuit / rare short circuit. In addition, it can be performed by a single device, so that it is possible to greatly reduce the time and effort required for the soundness diagnosis of the transformer and to greatly reduce the cost of facilities and equipment. Furthermore, by setting two threshold values, it is possible to clearly discriminate between occurrence of winding disconnection and occurrence of rare short-circuit, etc. Prevents accidental diagnosis of a short-circuit condition or the fact that a measurement terminal connection failure is actually diagnosed as a rare short-circuit condition. Therefore, it is possible to improve the reliability as a soundness diagnosis technique for transformers.

  Moreover, according to the transformer health diagnosis method and the health diagnosis device of the present invention, it is possible to determine the transformer health without taking the effort of sweeping the frequency over a certain range. Therefore, it is possible to greatly reduce the time and labor required for the two determination processes, greatly reduce the measurement time, and perform two determination processes with only one apparatus, which is versatile as a soundness diagnosis technique. Improvements can be made. In the case of performing measurement by sweeping the frequency in the low frequency band, the measurement time is generally long. However, according to the present invention, this is not necessary, so that the measurement time can be greatly reduced as compared with the conventional method. It becomes possible.

  In addition, according to the transformer health diagnosis method and the health diagnosis device of the present invention, the occurrence of wire breakage due to only one input voltage application and output voltage detection (in other words, transfer function measurement). Since it is possible to determine whether or not there is a short circuit between turns and whether or not a rare short has occurred, it is possible to greatly reduce the time required for the two determination processes and greatly reduce the measurement time. Two determination processes can be performed by a single device, and it becomes possible to improve versatility as a soundness diagnostic technique for a transformer.

  In addition, according to the transformer health diagnosis method and the health diagnosis device of the present invention, the health of the transformer can be determined without opening and closing the top cover of the transformer. It is possible to improve versatility by avoiding the loss of the soundness of the transformer. In particular, even if the installation location of the transformer is outdoors, according to the present invention, the upper lid is not opened and closed, so there is no need to pay attention to the maintenance of the internal state of the transformer, and the field applicability can be greatly improved. It becomes possible.

  Furthermore, according to the transformer health diagnosis method and the health diagnosis device of the present invention, it is possible to appropriately determine whether or not a rare short circuit has occurred particularly for a transformer having a rated capacity of about 5 to 100 [kVA]. Therefore, it becomes possible to improve the reliability as a soundness diagnostic technique of a transformer.

  In addition, according to the transformer health diagnosis method and the health diagnosis device of the present invention, it is possible to appropriately determine whether or not the winding is broken particularly for a transformer having a rated capacity of about 5 to 100 [kVA]. Therefore, it is possible to improve the reliability as a soundness diagnosis technique for a transformer.

  Further, according to the transformer diagnostic method and the diagnostic apparatus of the present invention, the power supply mechanism can be reduced in size, so that the configuration of the apparatus can be made compact and the size can be sufficiently held with one hand. As a result, it is possible to improve convenience and versatility as a soundness diagnosis technique for transformers.

It is a flowchart explaining an example of embodiment of the soundness diagnostic method of the transformer of this invention. It is a functional block diagram explaining an example of embodiment of the soundness diagnostic apparatus of the transformer of this invention. It is a figure explaining the transfer function measuring method. It is a figure which shows the measurement result of the transfer function of a verification test. It is a figure explaining the winding structure of the pole transformer of a verification test. It is a functional block diagram explaining an example (Example 1) of the concrete circuit structure of the soundness diagnostic apparatus of the transformer of this invention. It is a functional block diagram explaining the other example (Example 2) of the concrete circuit structure of the soundness diagnostic apparatus of the transformer of this invention. It is a functional block diagram explaining further another example (Example 3) of the concrete circuit structure of the soundness diagnostic apparatus of the transformer of this invention.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  FIG. 1 and FIG. 2 show an example of embodiments of a transformer health diagnosis method and a health diagnosis device according to the present invention. As shown in FIG. 1, the method for diagnosing the health of a transformer according to the present invention uses the transfer function of the secondary winding in the frequency band where the first resonance of the transfer function appears when the winding is normal as the primary winding. Is calculated from the input voltage applied to the secondary winding in the open state and the detected output voltage (S1, S2), and when the value of the transfer function is less than the first threshold value, the primary winding It is determined that a disconnection has occurred (S3: Yes), and if it is equal to or greater than the second threshold value, it is determined that a short circuit between turns or a rare short has occurred in the primary winding (S4: Yes). In other cases (S3: No and S4: No), it is determined that the primary winding is normal (S5).

  In addition, the transformer health diagnosis apparatus according to the present invention applies a means for applying an input voltage to the secondary winding while the primary winding is open, and detecting an output voltage, and when the winding is normal. The transfer function of the secondary winding in the frequency band where the first resonance of the transfer function appears is calculated from the input voltage and the output voltage, and when the value of the transfer function is less than the first threshold value, the primary winding It is determined that a disconnection has occurred, and if it is greater than or equal to the second threshold value, it is determined that a short circuit between turns or a rare short has occurred in the primary winding, and in other cases the primary winding Is provided with means for determining that is normal.

  In the present embodiment, a case in which the transformer health diagnostic method shown in FIG. 2 is performed by the transformer health diagnostic apparatus 10 will be described as an example. The transformer health diagnostic apparatus 10 applies a voltage application / detection unit 11 as a means for detecting an output voltage while applying an input voltage to a secondary winding in a state where the primary winding is opened. The transfer function calculation unit 12a for calculating the transfer function of the secondary winding from the input voltage and the output voltage in the frequency band where the first resonance of the transfer function when normal occurs, and the value of the transfer function is less than the first threshold value In some cases, the disconnection presence / absence determination unit 12b that determines that a disconnection has occurred in the primary winding and the value of the transfer function are equal to or greater than the second threshold value. It is determined that there is a disconnection in the primary winding when the transfer function value is less than the first threshold value. If the second threshold is exceeded, the primary winding is short between turns. Or it determines that the short circuit occurs, in other cases and a determination section 12 as means for determining the primary winding is normal.

  The voltage application / detection unit 11 has a pair of terminals 16 and 16 (specifically, for example, clips) connected to the secondary winding of the transformer to be diagnosed, and leads 17 and 17 connected to the terminals. Attached through.

  In addition, the transformer health diagnostic apparatus 10 according to the present embodiment includes a display unit 13 for displaying operation contents, measurement results, and the like, and an input unit 14 for providing instructions and instructions of workers to the apparatus. Is further provided. Specifically, the display unit 13 is, for example, an LCD display or a lamp provided corresponding to a display item. The input unit 14 is specifically an operation key, a button provided corresponding to an input item, or a changeover switch.

  The voltage application / detection unit 11, the determination unit 12, the display unit 13, and the input unit 14 are connected by a signal line such as a bus so that signals such as data and control commands are input / output.

  The transformer health diagnostic apparatus 10 further includes a memory, a sound generation circuit, a speaker, and the like for configuring a work area and a data storage area when performing processing related to the transformer health diagnosis. Anyway.

  In addition, the transformer health diagnostic apparatus 10 includes a power supply circuit unit 15 that supplies power to each unit of the apparatus 10. Here, based on the knowledge obtained by the above-described analysis and examination by the present inventors, the input voltage applied for calculating the transfer function is 2 [if the rated capacity of the transformer is 10 [kVA]. V] is sufficient, and even in the case of a wide range of transformers with a rated capacity up to 100 [kVA], about 3.5 to 5 [V] is sufficient. And if it is an input voltage of about 3.5-5 [V], it is possible to operate the soundness diagnostic apparatus 10 of a transformer with small batteries, such as a dry cell, Therefore It is necessary to provide a large-sized power supply unit. In addition, the transformer health diagnostic apparatus 10 can be made very compact to such an extent that it can be sufficiently held with, for example, one hand.

  Specifically, for example, the power supply circuit unit 15 of the transformer health diagnosis apparatus 10 may be configured by a circuit that connects two 1.2 to 1.5 V dry batteries in series and supplies 2.4 to 3 [V]. It is done. In this case, a booster circuit or the like for adjusting the voltage of the power supplied from the power source to the input voltage is appropriately provided. Also, application of input voltage and detection of output voltage for judgment of occurrence of winding breakage, detection of input voltage and detection of output voltage for judgment of occurrence of short circuit between turns and rare short circuit, respectively. In the case of the configuration to be performed, considering that the higher the input voltage can be expected to improve the measurement accuracy when determining whether or not the winding is disconnected, the power supply circuit unit 15 is connected in series with two 9V stacked batteries. Thus, it is conceivable to configure a circuit for supplying 18 [V] or a circuit for supplying 9 [V] by connecting two 9V stacked batteries in parallel. In this case, a step-down circuit or the like for adjusting the voltage of the power supplied from the power source to the input voltage is appropriately provided. Thus, by configuring the power supply circuit unit 15 with, for example, a 1.2 to 1.5 V dry battery or a 9 V stacked battery, it becomes very easy to secure and maintain the power supply, and the versatility as a transformer health diagnosis device is improved. Improvement is achieved.

  In carrying out the present invention, first, the input voltage is applied to the secondary winding of the transformer to be diagnosed and the output voltage from the secondary winding is detected (S1).

  In the present invention, the secondary winding in the frequency band where the first resonance of the transfer function appears when the transformer to be diagnosed is normal with the primary winding of the transformer opened (ie, the first resonance frequency band). Calculate the transfer function of the line. For this reason, in the present invention, with the primary winding of the transformer open, an input voltage having a frequency within the range of the first resonance frequency band is applied to the secondary winding and from the secondary winding. Detect (measure) the output voltage.

  The measurement for calculating the transfer function is performed, for example, in the same manner as conventionally used in frequency response analysis performed on a transformer. On the other hand, in the conventional frequency response analysis, since it is necessary to sweep the frequency, it is essential to use a measuring device having a frequency sweep function (see, for example, FIG. 3), but in the present invention, it is not necessary to sweep the frequency. Therefore, the voltage application / detection unit 11 and the determination unit 12 may be configured to perform measurement only at a specific frequency.

  When performing measurement only at a specific frequency, specifically, for example, the voltage application / detection unit 11 includes a sine wave generation circuit, an amplification circuit, a 50Ω resistor, a DC conversion circuit (applied sine wave voltage → DC A configuration including a voltage conversion circuit, a detected AC voltage → DC voltage conversion circuit), and a voltmeter may be considered. In other words, the measurement device that has been used in the frequency response analysis has a configuration that does not have a frequency sweep function, and specifically, for example, the measurement device 5 shown in FIG. 3 does not have a frequency sweep function. Can be considered.

  Here, in the present invention, the transfer function in the frequency band where the first resonance of the transfer function appears when the winding of the transformer to be diagnosed is normal (that is, the first resonance frequency band) is measured. Specifically, for example, based on the knowledge obtained by the above-described analysis and examination by the present inventors, for example, in the case of a transformer having a rated capacity of about 5 to 100 [kVA], approximately 10 to 1000 [Hz]. It is conceivable to measure the transfer function using a frequency selected from the range of as a measurement frequency. However, the range of the measurement frequency in the present invention is not limited to the range of 10 to 1000 [Hz], and the frequency band in which the first resonance of the transfer function appears when the winding of the transformer to be diagnosed is normal. If so, a frequency outside the above range may be used.

  When the frequency at which the transfer function is measured is uniquely determined, it is the same type of transformer as the diagnosis target transformer (specifically, the rated capacity is the same and the iron core characteristics are the same), and it is normal. If there is an existing measurement result of the transfer function, the measurement frequency may be determined using the measurement result, or the first resonance frequency may be calculated based on the design specification of the transformer to be diagnosed. The measurement frequency may be determined using the calculation result. For the same type of transformer, the transfer functions are the same (except for measurement errors and individual differences), and therefore the frequencies and frequency bands where resonance appears are the same, so the same for multiple transformers of the same type. Measurement may be performed at the measurement frequency.

  In the present invention, the input voltage is applied and the output voltage is detected at one or a plurality of frequencies in the first resonance frequency band, and the value of the transfer function is calculated. For the establishment of the present invention, only one point is sufficient to calculate the transfer function value. For example, when it is desired to ensure the soundness diagnosis, measurement may be performed at a plurality of frequencies. .

  Also, in order to clarify the shape of the transfer function unique to the transformer and confirm the first resonance frequency band so that the measurement frequency can be examined, the frequency is swept continuously in a certain frequency range, that is, the frequency is swept. However, the transfer function may be measured while the transfer function is being measured. The frequency sweep range is set to, for example, 10 to 9990 [Hz], considering that the first resonance frequency band can be substantially covered including at least the first resonance frequency of various transformers. Conceivable.

  Here, in the present embodiment, the voltage application / detection unit 11 applies the input voltage to the secondary winding of the transformer to be diagnosed based on the instruction from the transfer function calculation unit 12a of the determination unit 12 and 2 The output voltage from the next winding is detected.

  For the measurement frequency for applying the input voltage and detecting the output voltage and calculating the value of the transfer function, one or a plurality of measurement frequencies may be defined in advance in the transfer function calculation unit 12a. Alternatively, the operator may be able to select from a plurality of predefined frequencies via the display unit 13 and the input unit 14 during measurement, or the operator may select the display unit 13 during measurement. In addition, the number and frequency of measurement frequencies may be designated via the input unit 14.

  In addition, when the transfer function is measured while sweeping the frequency within a certain frequency range, the sweep start frequency and the sweep end frequency may be defined in advance in the transfer function calculation unit 12a. In the measurement, the operator may designate the sweep start frequency and the sweep end frequency via the display unit 13 and the input unit 14.

  In the present embodiment, the voltage application / detection unit 11 applies the input voltage and detects the output voltage at one frequency in the first resonance frequency band based on an instruction from the transfer function calculation unit 12a, and the value of the transfer function. Is calculated only once. Therefore, the subsequent processing from S2 to S5 is performed using the value of one transfer function obtained by the application of the input voltage and the detection of the output voltage and the calculation of the value of the transfer function.

  Then, the voltage application / detection unit 11 applies the input voltage to the secondary winding of the transformer to be diagnosed, detects the output voltage, and outputs the value of the detected output voltage to the determination unit 12. .

  Subsequently, the transfer function is calculated using the value of the input voltage applied in the process of S1 and the value of the detected output voltage (S2).

  The calculation of the transfer function is performed in the same manner as that conventionally used in frequency response analysis performed on a transformer, for example. Specifically, for example, the input voltage Vin (jω) applied to the secondary winding of the transformer to be diagnosed and the output voltage Vout (jω) based on the 50Ω impedance are measured, and the transmission defined by Equation 1 is performed. This is done by obtaining the function H (jω).

  In the present embodiment, the determination unit 12 receives the input of the output voltage value detected in the process of S1 from the voltage application / detection unit 11, and the transfer function calculation unit 12 a of the determination unit 12 receives the voltage application / detection unit 11. On the other hand, the value of the transfer function is calculated by Equation 1 using the value of the input voltage instructed to the output and the value of the detected output voltage.

  Then, the transfer function calculation unit 12a outputs the calculated transfer function value to the disconnection presence / absence determination unit 12b.

  Subsequently, it is determined whether or not the value of the transfer function obtained by the calculation in the process of S2 is less than the first threshold (S3).

  The first threshold value is a value of a transfer function for determining that the transformer winding is broken and the soundness of the transformer is impaired. For example, in the case of a transformer with a rated capacity of about 5 to 100 [kVA], the first threshold is specifically set to, for example, −50 to It is conceivable to set any value within the range of −40 [dB]. However, the first threshold value in the present invention is not limited to the range of −50 to −40 [dB], and is set based on the minimum value of the transfer function when normal in a transformer of the same type, for example. In other words, it may be set to a value smaller than the minimum value of the transfer function when it is normal.

  The first threshold value may be preliminarily defined in the disconnection presence / absence determination unit 12b, or the first threshold value may be operated during measurement from a plurality of preliminarily defined threshold values (specifically, transfer function values). An operator may be able to select via the display unit 13 and the input unit 14, or an operator may be able to specify via the display unit 13 and the input unit 14 during measurement.

  In the present embodiment, the disconnection presence / absence determination unit 12b of the determination unit 12 receives the transfer function value calculated in the process of S2 from the transfer function calculation unit 12a, and the transfer function value is less than the first threshold value. Judge whether there is.

  If the calculated transfer function value is less than the first threshold (S3: Yes), the disconnection presence / absence determination unit 12b has a disconnection in the winding of the transformer to be diagnosed. And that is displayed on the display unit 13. And the determination part 12 complete | finishes the process of the soundness diagnosis with respect to the said transformer (END).

  On the other hand, when the value of the calculated transfer function is equal to or larger than the first threshold (S3: No), the disconnection presence / absence determination unit 12b does not generate a disconnection in the winding of the transformer to be diagnosed. And that is displayed on the display unit 13. And the determination part 12 advances the process of the soundness diagnosis with respect to the said transformer to the process of S4.

  Subsequently, it is determined whether or not the value of the transfer function obtained by the calculation in the process of S2 is greater than or equal to the second threshold (S4).

  The second threshold value is a value of a transfer function for determining that a transformer short-circuit / rare short has occurred in the transformer winding and the soundness of the transformer is impaired. For example, in the case of a transformer having a rated capacity of about 5 to 100 [kVA], the second threshold is specifically set to, for example, −5 to 5 based on the knowledge obtained by the above-described analysis and examination by the inventors. It is conceivable to set any value within the range of 0 [dB]. However, the second threshold value in the present invention is not limited to the range of -5 to 0 [dB]. For example, when a short circuit between turns or a rare short circuit occurs in a transformer of the same type, or those are simulated. You may make it set based on the value of the transfer function in a state.

  More specifically, the measurement frequency (or the first frequency) is smaller than the value of the transfer function at the measurement frequency (or the first resonance frequency band) in the occurrence of a short circuit between turns or a rare short, or in the simulated state of generation, and the normal. Set to a value larger than the value of the transfer function in one resonance frequency band.

  The second threshold value may be specified in advance in the presence / absence determination unit 12c such as a rare short, or may be measured from a plurality of threshold values (specifically, transfer function values) specified in advance. The operator may be able to select via the display unit 13 and the input unit 14, or the operator may be able to specify via the display unit 13 and the input unit 14 during measurement.

  In the present embodiment, the presence / absence determining unit 12c of the determination unit 12 determines whether or not the value of the transfer function calculated in the process of S2 is equal to or greater than a second threshold value.

  If the calculated transfer function value is greater than or equal to the second threshold (S4: Yes), the presence / absence determination unit 12c such as a rare short is short-circuited between turns to the winding of the transformer to be diagnosed. It is determined that a rare short has occurred, and this is displayed on the display unit 13. And the determination part 12 complete | finishes the process of the soundness diagnosis with respect to the said transformer (END).

  On the other hand, when the value of the calculated transfer function is less than the second threshold (S4: No), the presence / absence determination unit 12c such as a rare short is short-circuited between turns to the winding of the transformer to be diagnosed. It is determined that a rare short has not occurred, and this is displayed on the display unit 13.

  When the value of the transfer function obtained by the calculation in the process of S2 is not less than the first threshold (S3: No) and less than the second threshold (S4: No), the determination unit 12 It is determined that the transformer winding to be diagnosed is free of disconnection, short-to-turn short-circuit / rare short, and that the transformer is kept sound, that is, normal (S5). The sex diagnosis process is terminated (END).

  According to the soundness diagnosis method and soundness diagnosis device for a transformer having the above-described configuration, determination of occurrence of breakage of the transformer winding and short circuit between turns using the first threshold value and the second threshold value・ Because it is possible to determine whether or not a rare short has occurred, the two determination processes can be performed as a series and can be performed by a single device, which saves time and effort for soundness diagnosis of the transformer. It is possible to greatly reduce the cost of facilities and equipment as well as to significantly reduce it. Furthermore, by setting two threshold values, it is possible to clearly discriminate between occurrence of winding disconnection and occurrence of rare short-circuit, etc. Prevents accidental diagnosis of a short-circuit condition or the fact that a measurement terminal connection failure is actually diagnosed as a rare short-circuit condition. Therefore, it is possible to improve the reliability as a soundness diagnosis technique for transformers. Moreover, the device configuration can be made compact so that it can be held with one hand.

  In addition, according to the transformer health diagnostic method and the health diagnostic device having the above-described configuration, the transformer health can be determined without taking the effort of sweeping the frequency over a certain range. In addition, the time required for the two determination processes can be greatly reduced, the measurement time can be greatly shortened, and the two determination processes can be performed using only a general-purpose device, thereby improving versatility as a soundness diagnosis technique. It becomes possible.

  In addition, according to the transformer health diagnosis method and the health diagnosis device having the above-described configuration, the winding is disconnected by applying the input voltage and detecting the output voltage (in other words, measuring the transfer function) only once. Since it is possible to determine whether or not a short circuit occurs and whether or not a short-circuit between turns or a rare short has occurred, the time required for the two determination processes can be greatly reduced and the measurement time can be greatly shortened. This makes it possible to perform two determination processes, and to improve versatility as a soundness diagnostic technique for transformers.

  In addition, although the above-mentioned form is an example of the suitable form of this invention, it is not limited to this, A various deformation | transformation implementation is possible in the range which does not deviate from the summary of this invention. For example, in the above-described embodiment, the determination unit 12 includes the transfer function calculation unit 12a, the disconnection presence / absence determination unit 12b, and the presence / absence determination unit 12c such as a rare short, which are configured to perform a series of processes. Applying the input voltage for the measurement frequency and detecting the output voltage only once, using the value of one output voltage obtained by the single detection, the transfer function calculation (S2) and the winding breakage The determination of occurrence / non-occurrence (S3) and the determination of occurrence / non-existence of rare shorts (S4) are performed, but the disconnection presence / absence determination unit 12b and the presence / absence determination unit 12c of rare shorts are provided as separate configurations. In addition, the application of the input voltage and the detection of the output voltage for the determination of the occurrence of the wire breakage and the detection of the input voltage and the detection of the output voltage for the determination of the presence or absence of the occurrence of a short circuit, etc. Cormorant (ie do convenience twice) as may be. This configuration is useful in that it eliminates wasteful processing when it is desired to inspect only the occurrence of wire breakage or to inspect only the occurrence of rare shorts. Alternatively, a continuity test unit that inspects only the continuity of the transformer to be diagnosed may be provided separately. Such a configuration is useful in that it is possible to first confirm whether the terminal 16 and the lead wire 17 connected to the secondary winding of the transformer to be diagnosed are good or bad. That is, first, a continuity test is performed. When it is confirmed that the continuity is good, the determination unit 12 determines whether or not a winding breakage or a short-circuit has occurred, while the continuity is poor. If it is determined, the connection state is confirmed and corrected if necessary, and then the determination unit 12 determines whether or not a winding break or a rare short has occurred. Thereby, since the possibility of a device-like connection failure can be excluded in advance when the value of the transfer function is less than the first threshold value, the interpretation of the determination result by the determination unit 12 can be limited. It is possible to avoid unnecessary troubles such as re-measurement and determination after confirming a typical connection state.

  Further, in the above-described embodiment, the measurement frequency for determining the occurrence of wire breakage is the same as the measurement frequency for determining the occurrence of rare shorts, etc., but the measurement frequency for each determination May have different frequencies. In this case, for example, the measurement frequency for determining whether or not the winding is broken is set to 20 [Hz], and the measurement frequency for determining whether or not a rare short is generated is set to 200 [Hz]. Thus, the value of the transfer function when the winding is normal is large at a low frequency, whereas the first threshold value corresponding to a small value corresponds to the value of the transfer function when the winding is normal, and the value of the transfer function is several hundred [ The second threshold value having a large value corresponds to a small frequency at a frequency of [Hz], and the determination error can be avoided more reliably.

  An example of a specific circuit configuration of the transformer health diagnostic apparatus of the present invention will be described with reference to FIG.

  The transformer health diagnostic apparatus 10 of this embodiment includes a terminal 16 connected to a secondary winding of a transformer to be diagnosed and a lead 17 connected to the terminal 16, and a sine wave as a voltage application / detection unit 11. A generation circuit 11a, an amplification circuit 11b, a differential amplification circuit 11b ′, a 50Ω resistor 11c, and a DC conversion circuit 11d are provided.

  The sine wave generation circuit 11a is for transmitting a sine wave to be applied to a transformer to be diagnosed. In the present embodiment, the sine wave generation circuit 11a is configured by a circuit that generates a sine wave of a DDS (Digital Dielectric Synthesis) system. .

  The amplifier circuit 11b is an amplifier circuit for driving the 50Ω resistor 11c.

  The differential amplifier circuit 11b ′ amplifies the difference between the input voltage and the output voltage.

  The DC conversion circuit 11d converts an AC voltage into a DC voltage equal to the effective value and inputs the DC voltage to the AD converter 23 of the MPU.

  The transformer health diagnosis apparatus 10 of this embodiment has an MPU (abbreviation of Micro Processing Unit) for controlling the entire apparatus, and is disconnected from the transfer function calculation section 12a as the determination section 12 in the MPU. A presence / absence determination unit 12b and a presence / absence determination unit 12c such as a rare short are configured.

  In addition, the transformer health diagnosis apparatus 10 of this embodiment further includes an LCD display as the display unit 13, an operation key as the input unit 14, and a memory 21, which are connected to the MPU by a bus to provide a signal. Is input / output.

  In the figure, reference numeral 22 denotes an analog multiplexer (switching device), which is a measurement switching device between the signal source (that is, the original signal voltage) and the 50Ω resistor 11c.

  The power supply circuit unit 15 is configured by connecting two nickel metal hydride batteries (AA) in series, and includes an MPU, a display unit 13, and an analog circuit (specifically, a sine wave generation circuit 11a and an amplification circuit 11b). , 50Ω resistor 11c, differential amplifier circuit 11b ′, analog multiplexer 22, DC converter circuit 11d), and generates power. Note that power is supplied to the MPU without changing the voltage, and the display unit 13 and the analog circuit are boosted to 5 [V] and supplied with power. Moreover, you may make it comprise the power supply circuit part 15 using a 9V laminated type battery.

  In the present embodiment, the shape of the transfer function inherent to the transformer is clarified, the first resonance frequency band is confirmed, and the measurement frequency can be studied, and the soundness of the transformer at the frequency based on the examination result. In order to make it possible to calculate the value of the transfer function for the determination, a mode in which the transfer function is measured while sweeping the frequency in the range of 20 to 9900 [Hz], and the frequency is designated within the range. Thus, the mode for calculating the value of the transfer function can be selected.

  The selection of the measurement mode and the designation of the measurement frequency are given to the sine wave generation circuit 11a by the instruction from the operator input by the input unit 14 via the MPU.

  In this embodiment, the first threshold value, which is the value of the transfer function for determining whether or not the transformer winding is disconnected, is -5 [dB], and the transformer winding is short-circuited between turns. The second threshold, which is the value of the transfer function for determining whether or not a rare short has occurred, is -50 [dB]. By setting two thresholds in this way, it is possible to distinguish between occurrence of winding breakage and occurrence of rare short, etc., and actually determine the state where winding breakage has occurred. Incorrectly diagnosing a situation where a rare short has occurred, or in fact diagnosing a situation where a measurement terminal is poorly connected as a rare short, etc. It becomes possible to prevent.

  And while the primary winding of the transformer to be diagnosed is open, the input voltage is applied to the secondary winding of the transformer via the connection terminal 16 and the output voltage from the secondary winding is detected, The transfer function calculation unit 12a in the MPU calculates the value of the transfer function, the disconnection presence / absence determination unit 12b compares the transfer function value with the first threshold value to determine whether or not the winding is disconnected, and a rare short The equality determination unit 12c compares the value of the transfer function with the second threshold value to determine whether or not a short circuit between turns and a rare short circuit have occurred.

  According to the transformer health diagnostic apparatus 10 of the present embodiment, the determination of the occurrence of wire breakage and the short-circuit between turns by only applying the input voltage and detecting the output voltage and calculating the value of the transfer function. -Since it is possible to determine whether or not a rare short has occurred, it is possible to reduce the time and labor required for two determination processes and shorten the measurement time, and to perform two determination processes with a single device, It becomes possible to improve versatility as a soundness diagnosis technique. Furthermore, by setting two threshold values, it is possible to clearly discriminate between occurrence of winding disconnection and occurrence of rare short-circuit, etc. Prevents accidental diagnosis of a short-circuit condition or the fact that a measurement terminal connection failure is actually diagnosed as a rare short-circuit condition. Therefore, it is possible to improve the reliability as a soundness diagnosis technique for transformers.

  Further, according to the transformer health diagnostic apparatus 10 of the present embodiment, since the transfer function can be measured while sweeping the frequency within a certain range, for example, the transformer has no diagnosis results so far. Even when it is necessary to identify the first resonance frequency band, the shape of the transfer function unique to the transformer can be clarified, and the first resonance frequency band can be confirmed to examine the measurement frequency. It is possible to improve the reliability and reliability and further improve the versatility of the soundness diagnosis apparatus. If the transformer is of the same type, the transfer function is the same (except for measurement errors and individual differences), and therefore the frequency and frequency band at which the resonance appears are the same, so frequency sweep measurement to confirm the transfer function shape Is enough at once.

  In addition, the transformer health diagnostic apparatus 10 of this embodiment is configured to have a size that can be held sufficiently with one hand because the power supply circuit unit 15 is formed of a dry battery.

  Another example of the specific circuit configuration of the transformer health diagnostic apparatus of the present invention will be described with reference to FIG.

  The transformer health diagnostic apparatus 10 of this embodiment includes a terminal 16 connected to a secondary winding of a transformer to be diagnosed and a lead 17 connected to the terminal 16, and a sine wave as a voltage application / detection unit 11. A generation circuit 11a and DC conversion circuits 11d-A and 11d-B are provided.

  The sine wave generation circuit 11a is for transmitting a sine wave to be applied to the transformer to be diagnosed. In this embodiment, the frequency of the generated sine wave is 200, 250, 300, 400, 500 [Hz]. Can be switched from within.

  The DC conversion circuit 11d-A converts a sine wave voltage applied to the transformer to be diagnosed into a DC voltage, and the DC conversion circuit 11d-B converts the AC voltage detected from the transformer to be diagnosed into a DC voltage. It is to convert to.

  In addition, a transfer function calculation unit 12a as a determination unit 12, a disconnection presence / absence determination unit 12b, and a presence / absence determination unit 12c such as a short circuit are configured in a circuit connected to the DC conversion circuits 11d-A and 11d-B.

  In addition, the display unit 13 includes a rare short occurrence notification lamp 13A that is turned on when it is determined that a short-to-turn short circuit / rare short circuit has occurred in the winding of the transformer to be diagnosed, and the winding of the transformer to be diagnosed. A normal notification lamp 13B that is turned on when it is determined that there is no short-to-turn short circuit / rare short circuit or disconnection, and a light that is determined that a disconnection has occurred in the winding of the transformer to be diagnosed. A disconnection occurrence notification lamp 13C.

  The power supply circuit unit 15 is configured by connecting two nickel-metal hydride batteries (AA) in series, and generates a power supply and supplies power to each of the above-described components. In addition, you may make it comprise the power supply circuit part 15 using a 9V laminated type battery.

  In this embodiment, the first threshold, which is the value of the transfer function for determining whether or not the transformer winding is broken, is set to −5 [dB], and the transformer winding is short-circuited between turns and rare-shorted. The second threshold value, which is the value of the transfer function for determining whether or not the occurrence of occurrence, is -50 [dB]. By setting two thresholds in this way, it is possible to distinguish between occurrence of winding breakage and occurrence of rare short, etc., and actually determine the state where winding breakage has occurred. Incorrectly diagnosing a situation where a rare short has occurred, or in fact diagnosing a situation where a measurement terminal is poorly connected as a rare short, etc. It becomes possible to prevent.

  And while the primary winding of the transformer to be diagnosed is open, the input voltage is applied to the secondary winding of the transformer via the connection terminal 16 and the output voltage from the secondary winding is detected, The transfer function calculation unit 12a calculates the value of the transfer function, and the disconnection presence / absence determination unit 12b compares the transfer function value with the first threshold value to determine the presence / absence of occurrence of winding disconnection and the presence / absence determination of rare short The unit 12c compares the value of the transfer function with the second threshold value to determine whether or not a short circuit between turns and a rare short circuit have occurred.

  Here, in this embodiment, the input voltage is applied and the output voltage is detected at any one of the measurement frequencies 200, 250, 300, 400, and 500 [Hz], and the value of the detected output voltage is detected. Is input to the transfer function calculation unit 12a, the value of the transfer function is calculated, the value of the transfer function is input to the disconnection presence / absence determination unit 12b, and the presence / absence of occurrence of the disconnection of the winding is determined and the presence / absence of a rare short Input to the determination unit 12c determines whether or not a short-to-turn short circuit / rare short circuit has occurred.

  According to the transformer health diagnostic apparatus 10 of the present embodiment, the determination of the occurrence of wire breakage and the short-circuit between turns by only applying the input voltage and detecting the output voltage and calculating the value of the transfer function. -Since it is possible to determine whether or not a rare short has occurred, it is possible to reduce the time and labor required for two determination processes and shorten the measurement time, and to perform two determination processes with a single device, It becomes possible to improve versatility as a soundness diagnosis technique. Furthermore, by setting two threshold values, it is possible to clearly discriminate between occurrence of winding disconnection and occurrence of rare short-circuit, etc. Prevents accidental diagnosis of a short-circuit condition or the fact that a measurement terminal connection failure is actually diagnosed as a rare short-circuit condition. Therefore, it is possible to improve the reliability as a soundness diagnosis technique for transformers.

  In addition, the transformer health diagnostic apparatus 10 of this embodiment is configured to have a size that can be held sufficiently with one hand because the power supply circuit unit 15 is formed of a dry battery.

  Still another example of the specific circuit configuration of the transformer health diagnostic apparatus of the present invention will be described with reference to FIG.

  In this embodiment, the continuity test unit 18 is provided separately from the determination unit 12.

  Also in the case of the present embodiment, the transformer health diagnostic apparatus 10 includes a terminal 16 connected to the secondary winding 2B of the transformer 1 to be diagnosed and a lead 17 connected to the terminal 16. However, in this embodiment, the input / output via the connection terminal 16 and the lead 17 is switched between the determination unit 12 and the continuity test unit 18. Yes.

  In the present embodiment, in relation to the continuity test unit 18, the continuity test pass indicator lamp 13D that is turned on when the continuity of the winding of the transformer 1 is confirmed as the display unit 13 (in other words, the continuity is good). And a continuity test failure display lamp 13E that is turned on when continuity cannot be confirmed (in other words, continuity is poor).

  In this embodiment, the continuity test unit 18 receives the power supply from the power supply circuit unit 15 and measures the resistance of the transformer 1 and compares the measured resistance value with the continuity threshold value to determine whether the continuity is good. to decide. In addition, the conduction threshold value for determining the quality of conduction is not limited to a specific value, and is set to an appropriate value based on the characteristics of the transformer 1 and the like. Specifically, for example, if the resistance value in the case of good conduction (in a normal transformer of a certain type and a certain range of rated capacity) is 10 [Ω] or less, the conduction threshold is set to 30 [Ω If the measured resistance value is less than 30 [Ω], it is judged that conduction is good (that is, at least equipment connection is good). It can be considered that there is a possibility of a general connection failure.

  In this embodiment, the voltage application / detection unit 11 includes a sine wave generation circuit 11a and DC conversion circuits 11d-A and 11d-B.

  The sine wave generation circuit 11a is for transmitting a sine wave to be applied to the transformer 1 to be diagnosed. In this embodiment, the frequency of the generated sine wave is 200, 250, 300, 400, 500 [Hz. ] Can be switched from within.

  The DC conversion circuit 11d-A converts a sine wave voltage applied to the transformer 1 to be diagnosed into a DC voltage, and the DC conversion circuit 11d-B obtains an AC voltage detected from the transformer 1 to be diagnosed. It converts to DC voltage.

  In addition, a transfer function calculation unit 12a as a determination unit 12, a disconnection presence / absence determination unit 12b, and a presence / absence determination unit 12c such as a short circuit are configured in a circuit connected to the DC conversion circuits 11d-A and 11d-B.

  Further, in this embodiment, in relation to the determination unit 12, a rare short occurrence notification lamp that is turned on when it is determined that a short circuit between turns or a rare short has occurred in the winding of the transformer 1 as the display unit 13. 13A and the normal notification lamp 13B that is turned on when it is determined that there is no short-to-turn short circuit / rare short circuit or disconnection in the winding of the transformer 1, and the disconnection occurs in the winding of the transformer 1 A disconnection occurrence notification lamp 13C that is turned on when the determination is made is further provided.

  Moreover, the power supply circuit unit 15 of the transformer health diagnostic apparatus 10 of this embodiment is configured by connecting two 9V stacked batteries in series, and supplies power to each part of the apparatus. In the present embodiment, the supply destination of power from the power supply circuit unit 15 is switched between a configuration associated with the determination unit 12 and a configuration associated with the continuity test unit 18. . In addition, you may make it comprise the power supply circuit part 15 using a 9V laminated type battery.

  In this embodiment, the first threshold value, which is the value of the transfer function for determining whether or not the transformer winding is disconnected, is -5 [dB], and the transformer winding is short-circuited between turns. The second threshold, which is the value of the transfer function for determining whether or not a rare short has occurred, is -50 [dB]. By setting two thresholds in this way, it is possible to distinguish between occurrence of winding breakage and occurrence of rare short, etc., and actually determine the state where winding breakage has occurred. Incorrectly diagnosing a situation where a rare short has occurred, or in fact diagnosing a situation where a measurement terminal is poorly connected as a rare short, etc. It becomes possible to prevent.

  Furthermore, in this embodiment, the conduction threshold value, which is a resistance value for determining whether the transformer is conducting or not, is set to 30 [Ω].

  In this embodiment, first, with the primary winding of the transformer 1 to be diagnosed opened, the input / output via the connection terminal 16 and the lead 17 is set between the continuity test unit 18 and The resistance of the transformer 1 is measured through the connection terminal 16 and the lead 17, and the continuity test unit 18 compares the resistance value with the conduction threshold value to determine whether the transformer 1 is conductive. When the continuity test unit 18 determines that the continuity is poor, the device connection state is confirmed and then the process proceeds to the following process. On the other hand, when it is determined that the continuity is good, the process directly proceeds to the following process. If it is determined that there is a continuity failure, the continuity test may be performed again after confirming the device connection state, and then the following processing may be performed.

  Subsequently, in a state where the primary winding of the transformer 1 to be diagnosed is left open, input / output via the connection terminal 16 and the lead 17 is switched between the determination unit 12 and via the connection terminal 16. The input voltage is applied to the secondary winding of the transformer 1 and the output voltage from the secondary winding is detected, the transfer function calculation unit 12a calculates the value of the transfer function, and the disconnection presence / absence determination unit 12b transmits The function value is compared with the first threshold value to determine whether or not the winding is broken, and the short-circuit presence / absence determining unit 12c compares the transfer function value with the second threshold value to turn the winding. Determine whether there is a short circuit or rare short.

  Here, in this embodiment, the input voltage is applied and the output voltage is detected at any one of the measurement frequencies 200, 250, 300, 400, and 500 [Hz], and the value of the detected output voltage is detected. Is input to the transfer function calculation unit 12a, the value of the transfer function is calculated, the value of the transfer function is input to the disconnection presence / absence determination unit 12b, and the presence / absence of occurrence of the disconnection of the winding is determined and the presence / absence of a rare short Input to the determination unit 12c determines whether or not a short-to-turn short circuit / rare short circuit has occurred.

  According to the transformer health diagnostic apparatus 10 of the present embodiment, it is possible to determine the transformer health without taking time and effort to sweep the frequency over a certain range. It is possible to reduce the time and effort required for the processing and shorten the measurement time, and it is possible to perform two determination processes using only a general-purpose device, thereby improving the versatility as a soundness diagnosis technique.

  Also, according to the transformer health diagnostic apparatus 10 of the present embodiment, first, a continuity test is performed, and when it is confirmed that the continuity is good, occurrence of disconnection of the winding or rare short-circuit by the determination unit 12. On the other hand, if it is determined that the continuity is poor, the connection state is checked and corrected as necessary. In this case, the possibility of equipment connection failure can be eliminated in advance when the value of the transfer function is less than the first threshold value, so that the determination unit 12 interprets the determination result. It can be limited, and it becomes possible to avoid unnecessary troubles such as re-measurement and determination after confirming the device-like connection state.

  Further, according to the transformer health diagnostic apparatus 10 of this embodiment, when it is desired to determine only whether or not the winding is disconnected, input / output via the connection terminal 16 and the like is performed between the continuity test unit 18 and the like. It is possible to determine whether or not there is a break in the winding, and on the other hand, if it is desired to determine whether or not the winding is broken and whether there is a rare short, etc., input / output via the connection terminal 16 etc. To determine whether or not there is a break in the winding and whether or not there is a short circuit between turns or a rare short, and the procedure without unnecessary processing can be executed. It becomes possible to further improve versatility as a device.

  In addition, the transformer health diagnostic apparatus 10 of this embodiment is configured to have a size that can be held sufficiently with one hand because the power supply circuit unit 15 is formed of a dry battery.

DESCRIPTION OF SYMBOLS 10 Transformer health diagnostic apparatus 11 Transfer function measurement part 12 Determination part 12a Disconnection presence / absence determination part 12b Presence determination part, such as rare shorts

Claims (10)

  The transfer function of the secondary winding in the frequency band where the first resonance of the transfer function when the winding is normal appears as the input voltage applied to the secondary winding with the primary winding open. It is calculated from the output voltage, and when the value of the transfer function is less than the first threshold value, it is determined that a disconnection has occurred in the primary winding, and when it is greater than or equal to the second threshold value. It is determined that a short circuit between turns or a rare short has occurred in the primary winding, and in other cases, it is determined that the primary winding is normal. .   The frequency band in which the first resonance of the transfer function appears when the winding is normal is 10 to 1000 [Hz], and the transfer function of the secondary winding is calculated in the frequency band of 10 to 1000 [Hz]. The transformer soundness diagnostic method according to claim 1.   2. The transformer health diagnosis method according to claim 1, wherein the first threshold value is any value within a range of −50 to −40 [dB].   2. The transformer health diagnosis method according to claim 1, wherein the second threshold value is set to any value within a range of -5 to 0 [dB].   2. The transformer health diagnosis method according to claim 1, wherein the input voltage is set to 3.5 to 5 [V].   Means for applying an input voltage to the secondary winding and detecting an output voltage with the primary winding open, and the secondary in the frequency band where the first resonance of the transfer function appears when the winding is normal. A winding transfer function is calculated from the input voltage and the output voltage, and if the value of the transfer function is less than a first threshold, it is determined that a break has occurred in the primary winding. If it is equal to or greater than the second threshold value, it is determined that a short circuit between turns or a rare short has occurred in the primary winding, and in other cases, it is determined that the primary winding is normal. A transformer soundness diagnostic apparatus, characterized by comprising:   The frequency band in which the first resonance of the transfer function appears when the winding is normal is 10 to 1000 [Hz], and the transfer function of the secondary winding is calculated in the frequency band of 10 to 1000 [Hz]. The transformer soundness diagnostic apparatus according to claim 6, wherein:   The transformer health diagnostic apparatus according to claim 6, wherein the first threshold value is any value within a range of -50 to -40 [dB].   The transformer health diagnostic apparatus according to claim 6, wherein the second threshold value is any value within a range of −5 to 0 [dB].   7. The transformer health diagnostic apparatus according to claim 6, wherein the input voltage is 3.5 to 5 [V].

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