KR20080015667A - Insulation Monitoring System - Google Patents

Abstract

The present invention relates to an insulation monitoring system. More specifically, the present invention relates to an insulation monitoring system capable of distinguishing a phase in which an insulation state of an electric line including a load is the worst and an insulation state of the three phases of a three-phase electric line.

According to the present invention, it is possible to determine not only the leakage current or the insulation resistance value flowing between the earths of the cable line including the load, but also the information of the worst phase among the three phases (R, S, T) in the three-phase wire path. .

In addition, the alarm status and fault information can be displayed on the display unit or compared with the alarm level input from the input unit or the alarm level stored in the memory unit, or can communicate with or control a remote control device located at a remote location. Through the communication unit, it is possible to remotely monitor the various data detected by the remote site and the bad (or good) phase information or alarm status among the three phases.

Description

Insulation Monitoring System

1 is a circuit diagram of a conventional insulation monitoring system

2 is a circuit diagram of a first embodiment of an insulation monitoring system of the present invention.

Figure 3 is a circuit diagram of a second embodiment of the insulation monitoring system of the present invention.

Figure 4 is a circuit diagram of a third embodiment of the insulation monitoring system of the present invention.

5 is a circuit diagram of a fourth embodiment of an insulation monitoring system of the present invention.

6 is a circuit diagram of a fifth embodiment of an insulation monitoring system of the present invention.

7 is a block diagram of an embodiment of the insulation monitoring device used in FIGS.

8 is a detailed circuit diagram of an embodiment of the insulation monitoring device used in FIGS.

FIG. 9 is a detailed circuit diagram of a first embodiment of a voltage detecting means in an insulation monitoring apparatus used in FIGS. 7 to 8. FIG.

FIG. 10 is a detailed circuit diagram of a second embodiment of voltage detection means in an insulation monitoring apparatus used in FIGS. 7 to 8. FIG.

FIG. 11 is a detailed circuit diagram of a third embodiment of voltage detection means in an insulation monitoring apparatus used in FIGS. 7 to 8. FIG.

12 is a detailed circuit diagram of a fourth embodiment of a voltage detecting means in an insulation monitoring apparatus used in FIGS. 7 to 8. FIG.

FIG. 13 is a detailed circuit diagram of a fifth embodiment of voltage detection means in an insulation monitoring apparatus used in FIGS. 7 to 8. FIG.

14 is a detailed circuit diagram of another embodiment of the current detecting means in the insulation monitoring apparatus used in FIGS.

15 is a diagram illustrating phase difference detection according to the present invention.

16 is a flowchart illustrating operations of the embodiment of FIGS. 7 to 8.

<Explanation of symbols for the main parts of the drawings>

1: transformer 2: switchgear

3: wire 4: load

5: Ground Wire 6: Class 2 Ground

7: Class 3 Ground 8: Capacitance

9: insulation resistance 10: current transformer

12, 13, 14: voltage detection line 15, 30: insulation monitoring device

30: voltage detection means 31: voltage detection unit

32: phase selector 33: voltage filter

40: leakage current detection means 41: current / voltage conversion unit

42: amplifier 43: current filter

50: phase comparison means 51: voltage component waveform shaping unit

52: current component waveform shaping section 53: phase difference detection section

60: A / D conversion unit 70: operation control unit

80: input / output unit 82: input unit

84: display unit 86: storage unit

90: communication unit

311: 120 degrees or more 312: 240 degrees or more

The present invention relates to an insulation monitoring system. More specifically, the present invention relates to an insulation monitoring system capable of distinguishing a phase in which an insulation state of an electric line including a load is the worst and an insulation state of the three phases of a three-phase electric line.

The conventional method for monitoring an insulation state including a load on a cable line is to detect an image current component flowing through the ground line 5 in the grounded ground system on the secondary side of the transformer as shown in FIG. Detection methods have been used. In the present invention, "electric line" or "electric line" means not only a low voltage line including a load, but also a high voltage line.

The above conventional technique will be described in more detail.

As shown in FIG. 1, a commercial AC voltage is supplied to a load 4 through a transformer 1, a switch 2, and an electric wire 3 for converting a voltage.

In Fig. 1, the secondary side of the transformer 1 is wired (Y), the neutral point of the wire is grounded to the second type ground (6) through the ground wire (5), and between the wire path (3) and the ground The effective component current (Ir) due to the insulation resistance (9) component directly related to the insulation state and the capacitance, such as a noise filter, which is not directly related to the insulation state, but is long or has an input terminal of the load (4). The reactive component current Ic by the component (8) flows, and the image current I0 = Ir + Ic, which is the vector sum of the two components, flows through the ground line 5 of the transformer. A method of detecting an insulation state using the leakage current value detected on the secondary side of the image current transformer 10 by passing the image current 10 component in the middle of the ground line 6 of the transformer or the three phases of the wire path 3 collectively. This is commonly used a lot. Equipment using the above-described method of detecting the leakage current I0 includes an earth leakage breaker and an earth leakage alarm.

In the conventional method of detecting only the leakage current (I0) value as described above, it is not possible to distinguish among three-phase R, S, and T phases in which the insulation state is poor. If there is a time-consuming element to insulate all three phases R, S, and T with an insulation resistance meter such as mega, and if there is information on one poor phase among three phases R, S and T, It will be easier to identify the poor insulation point intensively.

Therefore, there has been a demand for an insulation monitoring system that can distinguish not only an insulation state such as a leakage current value, but also a phase having the worst insulation state among three-phase R, S, and T phases in a three-phase wire.

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to insulate the insulation of the cable line including the load in the three-phase cable line and the phase of the poorest insulation of the three-phase R, S, T phase It is to provide insulation system that can provide information.

Another object of the present invention is to provide an insulation monitoring system that can be remotely controlled through the display, alarm alarm output and communication unit by calculating the insulation resistance between the cable line and the ground.

Insulation monitoring system for monitoring the insulation state of the three-phase cable line of the present invention for achieving the object of the present invention comprises: a voltage detecting means for detecting the voltage component of the three-phase cable line and converting it into a constant magnitude; Image current transformer for detecting leakage current flowing between cable line and ground, and leakage current component which converts leakage current component detected in the image current transformer into voltage component to remove frequency component above a certain frequency or extract only component of commercial frequency band. Detection means; Phase comparing means for comparing the phase of the output value of the voltage detecting means with the output value of the leakage current detecting means; An analog / digital converter for converting the analog component of the output value of the leakage current detecting means into a digital component; An operation control unit for reading and outputting various data and having an operation and control function; And input and output means for inputting and displaying various data.

The voltage detecting means includes: a voltage detector for detecting a voltage component of each phase of the three-phase wire and converting the voltage component into a predetermined magnitude; and a phase selection unit for selecting one phase of each voltage component of the three phases converted by the voltage detector; And a voltage filter for removing a frequency component above a certain frequency from the output value component of the phase selector or extracting only a frequency component of a predetermined frequency band.

The leakage current detecting means includes a current / voltage converting unit for converting a leakage current component flowing between the wire path and the ground detected by the image current transformer into a voltage component, an amplifying unit for amplifying a component converted in the current / current converting unit; The current filter unit is configured to remove a frequency component above a certain frequency from the leakage current component amplified by the amplifier or to extract only a frequency component of a predetermined frequency band.

The phase comparing means includes a voltage component waveform shaping unit for waveform shaping the output value of the voltage detecting unit, a current component waveform shaping unit for waveform shaping the output value of the leakage current detecting unit, and an output value of the voltage component waveform shaping unit. And a phase difference detection unit for detecting a phase difference of the output value of the current component waveform shaping unit with respect to.

The voltage detection unit is composed of a series combination of a resistor or a capacitor, or a combination of a small capacity transformer and a resistor or a capacitor.

The input and output means includes an input unit having a function for inputting or selecting various data; A display unit for outputting to a display unit such as an LED or a buzzer; And a storage unit having a function capable of storing various data.

The input / output means may display not only a leakage current value or an insulation resistance value but also information on a bad or good phase.

In addition, the insulation monitoring system of the present invention preferably further comprises a communication unit for remote monitoring from the outside.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

2 is a circuit diagram of a second embodiment of the insulation monitoring system of the present invention, Figure 3 is a circuit diagram of a second embodiment of the insulation monitoring system of the present invention, Figure 4 is a circuit diagram of a third embodiment of the insulation monitoring system of the present invention. 5 is a circuit diagram of a fourth embodiment of the insulation monitoring system of the present invention, and FIG. 6 is a circuit diagram of a fifth embodiment of the insulation monitoring system of the present invention.

7 is a block diagram of an embodiment of the insulation monitoring device used in FIGS. 3 to 6, and FIG. 8 is a detailed circuit diagram of an embodiment of the insulation monitoring device used in FIGS. FIG. 9 is a detailed circuit diagram of a first embodiment of voltage detection means in the insulation monitoring apparatus used in FIGS. 7 to 8, and FIG. 10 is a second embodiment of voltage detection means in the insulation monitoring apparatus used in FIGS. 11 is a detailed circuit diagram of a third embodiment of the voltage detecting means in the insulation monitoring device used in FIGS. 7 to 8, and FIG. 12 is a detailed circuit diagram of the voltage detecting means in the insulation monitoring device used in FIGS. Fourth Embodiment A detailed circuit diagram, and FIG. 13 is a detailed circuit diagram of a fifth embodiment of the voltage detecting means in the insulation monitoring apparatus used in FIGS. FIG. 14 is a detailed circuit diagram of another embodiment of the current detecting means in the insulation monitoring device used in FIGS. 7 to 8. FIG. 15 is an explanatory diagram of phase difference detection according to the present invention, and FIG. 16 is a flowchart illustrating operations of the embodiment of FIGS. 7 to 8.

2 shows that the secondary connection of the transformer 1 is Y, the neutral point is grounded, and three voltage detection lines 12, 13, 14 for detecting the voltage component of the wire path 3 are used. 3 is an embodiment in which the phase voltage between grounds is detected, and FIG. 3 is an embodiment which is almost similar to that in FIG. 2, but the embodiment in which the secondary connection of the transformer 1 is delta Δ and the T phase is grounded once. FIG. 4 is an embodiment similar to that of FIG. 2, but using one voltage detection line 12 to detect voltage components between the earth lines of the cable line 3, and FIG. 5 is almost similar to FIG. 2. 2 is an embodiment in which the neutral phase (hereinafter referred to as N phase) is not installed up to the load side, so that the N phase does not pass through the image transformer 10, while FIG. 5 illustrates that the N phase is installed up to the load side and up to the N phase. The embodiment passed through 10) is intended to explain that the video current transformer 10 can be installed in the middle of the wire line 3 or in the middle of the ground wire 5. FIG. 6 shows that the secondary side connection of the transformer 1 is delta Δ, and is a non-grounding type implementation. Although the five embodiments are shown as shown in Figs. 2 to 6, the phase of the secondary connection of the transformer 1 and the three phases of the voltage detection means are detected or three phases are detected. There may be a method of converting or detecting two phases, although not shown in the drawings, and there may be an embodiment of a method of detecting line voltage, and the image current transformer 10 is not only in the middle of the wire line 3 but also in a switchgear. Various embodiments may be provided such that an embodiment may be provided between (2) and the transformer (1) or in the middle of the ground wire (5).

7 and 8 are detailed circuit diagrams of the insulation monitoring apparatus 20 of FIGS. 2 to 6. 9 to 13 are detailed circuit diagrams of the voltage detecting means 30 inside the insulation monitoring device 20 of FIGS. 7 and 8, and FIG. 14 is a leakage current inside the insulation monitoring device 20 of FIGS. 7 and 8. A detailed circuit diagram of another embodiment of the detecting means 40 is shown. FIG. 15 is an explanatory diagram illustrating a method of detecting a phase difference according to the present invention, and FIG. 16 is a view illustrating the operation of the insulation monitoring apparatus 20 of FIGS. It is a flowchart for doing so.

2, 7, and 8, which are embodiments of the present invention, will be described first.

In FIG. 2, 1 is a transformer for converting a voltage, and supplies electric power to the wire path 3 through the switch 92. FIG. 5 is a ground wire for connecting the neutral point of the transformer 1 to ground 6 for safety. The ground of the transformer is generally provided with two types of ground 6, and the load side is provided with three types of ground 7. In the future, there is a high possibility that it will be changed to the common ground without dividing the 2 types and 3 types of ground. On the other hand, insulation deterioration occurs in one of the three phases between the cable line 3 including the load 4 and the ground while power is supplied to the load 4 through the switchgear 2 and the three-phase wire path 3. When the lower surface of the insulation resistance 9 is lowered, the effective resistance leakage current Ir in phase with the voltage flows to the ground through the insulation resistance 9. In addition, the capacitance 8 is present between each of the three phases of the cable line 3 and the ground due to a long length of the three-phase cable line 3 or a component such as a noise filter present at the input of the load 4. . The capacitance 8 is not directly related to the insulation state, but the capacitance 8 is an inert component having a 90 degree phase difference from the voltage to the ground through the capacitance 8 because current flows in the AC component voltage. Leakage current Ic flows. In general, in a small wire system, the reactive leakage current (Ic) flowing to the three-phase integrated ground wire (5) because the capacitance (8) is balanced between the ground and the capacitance (8) is very small unbalanced state. This is a very small value. The effective leakage current Ir and the reactive leakage current Ic are the sum of the vectors (Ir + Ic = I0) and the ground wire 5, the transformer 1, the switchgear 2, and the wire path 3 through the earth. ), The leakage current flow circuit is formed, and when the image current (I0) component is detected, it is possible to know the insulation state between the grounds of the cable line 3 including the load 4, but any phase out of three phases is insulated. Since it is unknown, it is possible to distinguish an insulation deteriorated phase by knowing which phase of the image leakage current I0 is close to the phase voltage and phase between the grounds of the three phases.

An image current transformer 10 such as ZCT is used to detect the image leakage current I0 component, and voltage detection lines 12, 13, and 14 are used to detect the ground-to-earth voltage of the cable line 3. use. The voltage detection lines 12, 13 and 14 are connected to the voltage detection means 3 of the insulation monitoring apparatus 20 shown in detail in FIG. 7, and the secondary side of the image current transformer 10 is shown in FIG. It is connected to the leakage current detection means 40 of the insulation monitoring device 20 of 7.

FIG. 7 is a block diagram of an embodiment of the insulation monitoring apparatus 20 used in FIGS. 2 to 6.

Insulation monitoring device 20 of the present invention includes a voltage detecting means 30 for detecting the phase voltage between the ground of each of the three phases of the wire line (3) and converts it into a constant magnitude; The leakage current component of the secondary side of the current transformer 10 for detecting the image leakage current I0 flowing to the ground of the wire line 3 including the load is converted into a voltage component to remove a frequency component above a predetermined frequency or a commercial frequency. Leakage current detecting means (40) for extracting only components in the band; Phase comparison means (50) for comparing the phase of the output value of the voltage detection means (30) with the output value of the leakage current detection means (40); An analog / digital converter (60) for converting the analog component of the leakage current detecting means (50) into a digital component; an arithmetic controller (70) for reading and outputting various data and having arithmetic and control functions; Input and output means 80 for inputting and displaying data, and a communication unit 90 for remote monitoring from the outside.

According to FIG. 8, the voltage detecting means 30 for detecting the voltage component of the wire line 3 includes a voltage detecting part for converting the voltage component detected by the voltage detecting lines 12, 13, and 14 into a constant magnitude. 31) and a phase selector 32 for selecting the voltage component of each phase by the RST control signal controlled by the arithmetic and control unit 70 on the voltage component of each phase converted by the voltage detector 31; And a voltage filter unit 33 for removing a frequency component above a predetermined frequency or extracting only a component of a commercial frequency band from the voltage component of the phase selected by the phase selector 32, wherein the leakage current detecting means 40 is A current / voltage converter 41 for converting the leakage current component flowing between the wire path 3 and the ground detected by the secondary side of the image transformer 10 into a voltage component, and the current / voltage converter 41; An amplifier 42 for amplifying the leakage current component converted by The leakage current component amplified by the amplification unit 42 is composed of a current filter unit 43 for removing a frequency component of a predetermined frequency or more or only a component of a commercial frequency band, the phase comparison means 50 is Waveform shaping is performed on the voltage component waveform shaping section 51 for waveform shaping the voltage component of the wire line 3 detected by the voltage detecting means 30, and the leakage current component detected by the leakage current detecting means 40 described above. The waveform of the current component waveform shaping portion 52 and the above-described current component waveform shaping portion 52 for the voltage component of the wire path 3 waveform-shaped by the voltage component waveform shaping portion 51 And a phase difference detector 53 for detecting the phase difference of the leakage current component. The input / output means 80 includes an input unit 82 having a function of inputting or selecting various data, and display means such as an LED or a buzzer. Output to And a storage section 86 having a function of storing various data.

8 is a detailed circuit diagram of an embodiment of the insulation monitoring device 20 to be described below, and FIG. 16 is a flowchart of an operation of the insulation monitoring device 20. 9 to 13 will be described first.

Fig. 9 is a detailed circuit diagram of the first embodiment of the voltage detecting means 30 described above, each using three voltage detecting lines 12, 13, 14 to detect the earth-to-earth phase voltage of the cable line 3, respectively. In this embodiment, the resistance of the insulation monitoring device 20 is reduced by using two resistors, that is, six resistors per phase. Assuming that the phase voltage of the cable line 3 is 220V, since 220V is too high to be used in the insulation monitoring device 20, it can be read by the voltage filter unit 33 of the insulation monitoring device 20 and insulated. Since the voltage lower than the power supply voltage of the monitoring device 20 is preferably lowered, the R phase voltage is distributed by R1r and R2r so that the voltage applied to R2r becomes the phase voltage component of the R phase detected by the insulation monitoring device 20, The S phase voltage is divided by R1s and R2s so that the voltage applied to R2s becomes the phase voltage component of the S phase detected by the insulation monitoring device 20, and the T phase voltage is distributed by R1t and R2t to insulate the voltage applied to R2t. And a voltage detector 31 for causing a phase voltage component of the T phase detected by the monitoring device 20, wherein a point at which the phase voltage component of the R phase of the voltage detector 31 appears and a phase voltage component of the S phase appear. Recall c point where b point and T phase phase component appear Select point a to detect the R phase voltage by the RST control signal controlled by the arithmetic and control unit 70, point b to detect the S phase voltage, and point c to detect the T phase voltage. A voltage filter unit for removing a frequency component above a predetermined frequency or extracting only a frequency of a commercial frequency band by the voltage filter unit 33 of the voltage component Va of the phase selected by the phase selector 32 having a function capable of The voltage component Vf is extracted through (33).

Fig. 10 is a detailed circuit diagram of the second embodiment of the voltage detecting means 30 described above, each using three voltage detecting lines 12, 13 and 14 to detect the phase-to-earth phase voltage of the cable line 3, respectively. In this embodiment, one resistor, that is, three resistors in common with three resistors per phase, is used to reduce the voltage to be used in the insulation monitoring apparatus 20. In Fig. 9, which is the first embodiment of the voltage detecting means 30, the phase voltages of the phases corresponding to points a, b, and c are shown. In Fig. 10, sw1 of the phase selector 32 is selected. The difference is that only the voltage of the losing phase appears in the R2 resistance.

Fig. 11 is a detailed circuit diagram of the third embodiment of the voltage detecting means 30, which uses three voltage detecting lines 12, 13 and 14 to lower the phase-to-ground phase voltage of the cable line 3 to a constant voltage. A small-capacity transformer TR is used in the detection unit 31 in place of the three resistors R1r, R1s, and R1t in FIG. 9, which differs from the first embodiment, and the rest are similar to the first embodiment. .

FIG. 12 is a detailed circuit diagram of the fourth embodiment of the voltage detecting means 30. In contrast to the case where six resistors are used in FIG. 9, the first embodiment, six capacitors C1r, The difference is that the phase voltage of each phase is detected using C1s, C1t, C2r, C2s, C2t), and the remaining phase selector 32 and the voltage filter 33 are different from those of the first embodiment. same.

FIG. 13 is a detailed circuit diagram of the fifth embodiment of the voltage detecting means 30. In FIG. 9 to FIG. 11, the voltage detecting unit lowers the phase voltage of each of the three phases to a voltage value of a predetermined size by using three voltage detecting lines. On the other hand, in FIG. 13 according to the present embodiment, one voltage detection line 12 is used to lower the voltage to a predetermined size with two resistors R1 and R2, and the voltage components on the remaining phase are 120 degrees or more ( 311) shifts the phase of the voltage component represented by R2 by 120 degrees, and the voltage component of the other phases shifts the phase of the voltage component represented by R2 by 240 degrees or more by 312 degrees or more. The phase voltage component of each of the three phases is represented at point c. The remaining phase selector 32 and the voltage filter 33 are the same as in the first embodiment.

 For reference, in FIG. 13, the voltage detection line 12 is used to detect the voltage of the R phase, the voltage of the S phase is detected by using the 120 degree or more portion 311, and the voltage of the T phase is used by using the 240 degree or more portion 312. Is detected, there may be an embodiment using the voltage detection line 13, there may be an embodiment using the voltage detection line (14).

Then, the embodiment in which the configuration of the voltage detecting unit 31 of the voltage detecting unit 30 is replaced by three capacitors instead of the three resistors R2r, R2s, and R2t in FIG. 11 or only one resistor or one capacitor is used. There may be an embodiment of the present invention, and among the six capacitors of FIG. 12, an example in which three resistors (C2r, C2s, and C2t) are replaced by three resistors or one capacitor or one resistor may be used. There may be an embodiment in which two capacitors are substituted for the two resistors in FIG. 13, and there may also be an embodiment in which one resistor and one capacitor are used. Instead of (312), there may be an embodiment of shifting the 120 degree or more portion 311 and the phase by -120 degrees, or there may be an embodiment in which two 120 degree or more portions 311 are used.

Hereinafter, FIG. 8, which is an embodiment of the insulation monitoring device 20, and FIG. 16, which is an operation flowchart of the insulation monitoring device 20, will be described in detail.

As shown in FIG. 8, various data used in the insulation monitoring device 20, such as a keypad or a switch, in a main flow stored in the storage unit 86 of the insulation monitoring device 20. When the monitoring device 20 is installed, various data from the input unit 82 having a function of setting data such as a number address, an alarm set value, and an amplification factor for each component, for each insulation monitoring device 20 are provided. The setting 100 is executed. Next, the various data set by the input unit 82 or the various data previously stored in the storage unit 86 or the various data read-outs 110 which read various data input through the communication unit 90 from an external remote location. The operation is executed, and the electric wire path 3 is formed by the leakage current I0 and the voltage detection lines 12, 13, and 14 detected by the image current transformer 10 of the embodiment of the insulation monitoring system of Figs. When the voltage component Vf, If, θ read & store 120 is executed while the voltage component of each of the three phases of the phase is being input to the insulation monitoring device 20, the voltage detection lines 12, 13, and 14 described above. The voltage component of each of the three phases inputted by the insulation monitoring device 20 in the voltage detection unit 31 is the same as in the first embodiment (Fig. 9) to the fifth embodiment (Fig. 13) of the voltage detection means 31 described above. In the state where the voltage is divided into usable voltages, select sw1 of the phase selector 32 in the operation control unit 70 at point a. Sending a control signal RST, the voltage of the sw1 of the selector 32 is connected to ground as a point corresponding to the R component (Va) is input to a voltage filter portion 33 of the.

Since the voltage component Va of the R phase input to the voltage filter unit 33 is a component in which various frequencies are mixed, a component having a frequency higher than a predetermined frequency (for example, a commercial frequency) in the voltage filter unit 33 is used. The voltage component Vf, which is removed or extracted only a component of a predetermined frequency band (for example, a commercial frequency band), is output to the voltage component waveform shaping unit 51 and the analog / digital conversion unit 60.

As described above, the leakage current component I0 inputted to the leakage current detecting means 40 through the image current transformer 10 is the voltage component Ia in the current / voltage conversion section 41 that converts current into voltage. A voltage component corresponding to the leakage current amplified by the amplifying unit 42 and amplified by the amplifying unit 42 is converted to a predetermined frequency in the current filter unit 43. For example, the voltage component (If) corresponding to the leakage current from which the frequency component higher than the commercial frequency) or only the component of the predetermined frequency band (for example, the commercial frequency) is extracted is converted into the current component waveform shaping unit 52 and the analog / digital digital signal. Output to the converter 60.

The voltage component (Vf) input to the analog / digital converter 60 and the voltage component (If) corresponding to the leakage current are converted into digital values, read by the operation controller 70, and the Vf value is a Vf_R value. If values are stored in the storage unit 86 as If_R values.

Meanwhile, the voltage component Vf inputted to the voltage component waveform shaping unit 51 and the voltage component If corresponding to the leakage current input to the current component waveform shaping unit 52 are respectively shown in FIG. 15. The voltage component waveform shaping unit 51 compares the zero points of the voltage components Vf corresponding to the phase voltages of the R phases, and converts the digital values into high digital values when the value is greater than the zero point, and converts them into low digital values when the value is less than the zero point. The value voltage component V1 is output to the phase difference detector 53, and the current component waveform shaping unit 52 compares the zero point of the voltage component If corresponding to the leakage current to a digital value of High when the value is greater than zero. If less than zero, the digital value leakage current component I1 converted to the low digital value is output to the phase difference detection unit 53. The digital value voltage component V1 and the digital value leakage current component I1 outputted to the phase difference detection unit 53 are the digital value voltages corresponding to the voltage components of the R phase as shown in FIG. 15 in the phase difference detection unit 53. Digital value leakage based on the time when the component V1 changes from low to high Digital leakage based on the time when the current component I1 changes from low to high or when the digital value voltage component V1 changes from high to low The phase difference θ corresponding to the time when the current component I1 changes from high to low is detected and output to the arithmetic and control unit 70.

The phase difference θ of the R phase input to the arithmetic control unit 70 is read by the arithmetic control unit 70 and stored in the storage unit 86 as a θ_R value.

Next, when the Vf, If, &thetas; read &amp; store 130 of S phase in Fig. 16 is executed, the RST control signal to connect and select sw1 of the phase selector 32 as point b in the arithmetic and control unit 70 above. When sw1 of the phase selector 32 is changed to the point b and connected, the voltage component Va corresponding to the S phase is input to the voltage filter 33.

Since the voltage component Va of the S phase input to the voltage filter unit 33 is a mixed component of various frequencies, the voltage filter unit 33 has a component having a frequency higher than a predetermined frequency (for example, a commercial frequency). The voltage component Vf, which is removed or extracted only a component of a predetermined frequency band (for example, a commercial frequency band), is output to the voltage component waveform shaping unit 51 and the analog / digital conversion unit 60.

As described above, the leakage current component I0 inputted to the leakage current detecting means 40 through the image current transformer 10 is the voltage component Ia in the current / voltage conversion section 41 that converts current into voltage. A voltage component corresponding to the leakage current amplified by the amplifying unit 42 and amplified by the amplifying unit 42 is converted to a predetermined frequency in the current filter unit 43. For example, the voltage component (If) corresponding to the leakage current from which the frequency component higher than the commercial frequency) or only the component of the predetermined frequency band (for example, the commercial frequency) is extracted is converted into the current component waveform shaping unit 52 and the analog / digital digital signal. Output to the converter 60.

The voltage component (Vf) input to the analog / digital converter 60 and the voltage component (If) corresponding to the leakage current are converted into digital values and read by the operation controller 70, and the Vf value is Vf_S. If values are stored in the storage unit 86 as If_S values.

Meanwhile, the voltage component Vf inputted to the voltage component waveform shaping unit 51 and the voltage component If corresponding to the leakage current input to the current component waveform shaping unit 52 are respectively shown in FIG. 15. The voltage component waveform shaping unit 51 compares the zero point of the voltage component Vf corresponding to the phase voltage of the S phase, and converts it into a digital value of High if it is larger than the zero point and a digital value of Low if it is smaller than the zero point. The value voltage component V1 is output to the phase difference detector 53, and the current component waveform shaping unit 52 compares the zero point of the voltage component If corresponding to the leakage current to a digital value of High when the value is greater than zero. If less than zero, the digital value leakage current component I1 converted to the low digital value is output to the phase difference detection unit 53. The digital value voltage component V1 and the digital value leakage current component I1 outputted to the phase difference detection unit 53 are the digital value voltages corresponding to the voltage components of the S phase as shown in FIG. 15 in the phase difference detection unit 53. Digital value leakage based on the time when the component V1 changes from low to high Digital leakage based on the time when the current component I1 changes from low to high or when the digital value voltage component V1 changes from high to low The phase difference θ corresponding to the time when the current component I1 changes from high to low is detected and output to the arithmetic and control unit 70.

The phase difference θ of the S phase input to the arithmetic and control unit 70 is read by the arithmetic and control unit 70 and stored in the storage unit 86 as a θ_S value.

Next, when Vf, If, &thetas; reading &amp; storing 140 on T in Fig. 16 is executed, the RST control signal for connecting and selecting sw1 of the phase selection section 32 to point c in the arithmetic control section 70 above. When sw1 of the phase selector 32 is changed to point c and connected, the voltage component Va corresponding to the T phase is input to the voltage filter unit 33.

Since the voltage component Va of the T phase input to the voltage filter unit 33 is a component in which various frequencies are mixed, the component of the frequency higher than a predetermined frequency (for example, a commercial frequency) in the voltage filter unit 33 is used. The voltage component Vf that is removed or extracted only a component of a predetermined frequency band (for example, a commercial frequency band) is output to the voltage component waveform shaping unit 51 and the analog / digital conversion unit 60.

As described above, the leakage current component I0 inputted to the leakage current detecting means 40 through the image current transformer 10 is the voltage component Ia in the current / voltage conversion section 41 that converts current into voltage. A voltage component corresponding to the leakage current amplified by the amplifying unit 42 and amplified by the amplifying unit 42 is converted to a predetermined frequency in the current filter unit 43. For example, the voltage component (If) corresponding to the leakage current from which the frequency component higher than the commercial frequency) or only the component of the predetermined frequency band (for example, the commercial frequency) is extracted is converted into the current component waveform shaping unit 52 and the analog / digital digital signal. Output to the converter 60.

The voltage component (Vf) input to the analog / digital converter 60 and the voltage component (If) corresponding to the leakage current are converted into digital values and read by the operation controller 70, and the Vf value is a Vf_T value. If values are stored in the storage unit 86 as If_T values.

Meanwhile, the voltage component Vf inputted to the voltage component waveform shaping unit 51 and the voltage component If corresponding to the leakage current input to the current component waveform shaping unit 52 are respectively shown in FIG. 15. The voltage component waveform shaping unit 51 compares the zero points of the voltage components Vf corresponding to the phase voltages of the T phases, and converts them into digital values of high when the value is greater than zero and to digital values of low when the value is less than zero. The value voltage component V1 is output to the phase difference detector 53, and the current component waveform shaping unit 52 compares the zero point of the voltage component If corresponding to the leakage current to a digital value of High when the value is greater than zero. If less than zero, the digital value leakage current component I1 converted to the low digital value is output to the phase difference detection unit 53. The digital value voltage component V1 and the digital value leakage current component I1 outputted to the phase difference detection unit 53 are the digital value voltages corresponding to the voltage components of the T phase as shown in FIG. 15 in the phase difference detection unit 53. Digital value leakage based on the time when the component V1 changes from low to high Digital leakage based on the time when the current component I1 changes from low to high or when the digital value voltage component V1 changes from high to low The phase difference θ corresponding to the time when the current component I1 changes from high to low is detected and output to the arithmetic and control unit 70.

The phase difference θ of the T phase input to the arithmetic control unit 70 is read by the arithmetic control unit 70 and stored in the storage unit 86 as a θ_T value.

Next, when the phase difference comparison determination 150 shown in FIG. 16 is executed, the arithmetic and control unit 70 compares the smallest value among the phase difference values θ_R, θ_S, θ_T stored in the storage unit 86 as described above. The phase having the smallest phase difference among the T phases is determined to be a poorly insulating phase, and information of the most poorly insulating phase is stored in the storage unit 86. When the phase difference is determined in the order of the largest phase, the insulation is determined in the order of the best phase. It may be.

Next, when the calculation & output 160 of FIG. 16 is executed, the definition of the amplification factor or gain to be calculated as follows and used in the next calculation is as follows, and these values are set in the input unit 82 above. Or values stored in the storage unit 86 in advance.

A1: Amplification-related coefficients of the voltage detector 31

A2: Amplification-related coefficients of the voltage filter unit 32

B1: Amplification-related coefficients related to the primary / secondary winding ratio of the image transformer 10

B2: Amplification-related coefficients of the current / voltage converter 41

B3: Amplification-related coefficients of the amplifier 42

B4: Amplification-related coefficients of the current filter unit 43

I0: Leakage current flowing to the ground of the line 3 including the load

V60: Phase voltage at commercial frequency (50 Hz or 60 Hz)

In addition, the conversion-related amplification coefficient of the analog-to-digital converter 60 is set to one.

  However, If = (If_R + If_S + If_T) / 3

  However, Vf = (Vf_R + Vf_S + Vf_T) / 3

Using the leakage current and the phase voltage calculated in Equations 1 and 2 above, the value of the insulation resistance 9 between the cable line 3 and the ground can be calculated as in Equation 3 below.

Insulation resistance (R) with respect to the commercial current of the leakage current (I0) or the cable line (3) corresponding to the insulation state between the line (3) including the load (4) and the ground as shown in equations (1) to (3) above Display unit for displaying not only the value but also the most insulated (or good) phase information determined by the phase difference comparison determination 150 above on a display means such as FND or LCD, or on a display means such as an LED or a buzzer ( 84 may indicate not only the insulation state but also the information of the poorest insulation (or good) phase.

In addition, by using an input unit 82 having a function of inputting or selecting various data by means of a kind of a switch or a keypad, the leakage current component and the insulation resistance value are selectively displayed on the display unit 84, or If it is greater than the alarm level (leakage current) or less (insulation resistance) through the method of comparing with the alarm level input from the input unit 82 of the input unit 82 or the alarm level stored in the storage unit 86, the display unit 84 The alarm state can be displayed, or the communication unit 90 can output the various data calculated above and the information or alarm alarm with the most poor insulation (or good).

Next, Fig. 14, which is another embodiment of the leakage current detecting means 40, will be described.

In FIG. 8, the leakage current component detected through the current transformer 10 is converted into a voltage component by the current / voltage converter 41, and then amplified by the amplifier 42 and filtered by the current filter 43. On the contrary, in FIG. 14, the leakage current component detected through the image current transformer 10 is converted into a voltage component by the current / voltage converter 41 and first filtered by the current filter 43. There is a difference configured in the order of amplification in the amplification section 42 after.

In addition, in the embodiment of the present invention, the current / voltage converter 41 has an internal configuration of the insulation monitoring device 20 to detect leakage current. However, an electronic component such as a resistor is provided on the secondary side of the image current transformer 10. Direct connection may be an embodiment of the component having the function of the current / voltage conversion unit 41 of the insulation monitoring device 20 to the outside of the insulation monitoring device 20, the current / voltage conversion unit 41 There may also be an embodiment constituting the amplifier 42 having a function of. As described above with respect to the embodiment of the voltage detection means 30 for detecting the voltage component, there may be embodiments of various embodiments, and in the embodiment of the present invention, the voltage detection means 30 may be connected to the insulation monitoring apparatus 20. Although it is composed of the internal configuration of), there may be an embodiment of the whole or part of the portion having the function of the voltage detecting means 30 to the outside of the insulation monitoring device 20, without using a phase selector three phase three It is obvious that a person skilled in the present invention can be easily applied to various aspects within the scope of the present invention without departing from the gist of the present invention, such as there may be an embodiment constituting the voltage filter unit and the three voltage component waveform shaping units. .

In the three-phase cable line according to the present invention, the worst-case (or good) phase information among the three-phase (R, S, T) as well as accurately detecting leakage current or insulation resistance flowing between the grounds of the wire including the load. It can be determined until.

In addition, the alarm status and fault information can be displayed on the display unit or compared with the alarm level input from the input unit or the alarm level stored in the memory unit, or can communicate with or control a remote control device located at a remote location. It can remotely monitor the information or alarm status of the various data and the bad (or good) of the three phases detected remotely through a communication unit having a.

Claims (8)

In the insulation monitoring system for monitoring the insulation state of the three-phase wire, Voltage detecting means for detecting a voltage component of a three-phase wire and converting the same into a predetermined magnitude; Image current transformer for detecting leakage current flowing between cable line and ground, and leakage current component which converts leakage current component detected in the image current transformer into voltage component to remove frequency component above a certain frequency or extract only component of commercial frequency band. Detection means; Phase comparing means for comparing the phase of the output value of the voltage detecting means with the output value of the leakage current detecting means; An analog / digital converter for converting the analog component of the output value of the leakage current detecting means into a digital component; An operation control unit for reading and outputting various data and having an operation and control function; Insulation monitoring system, characterized in that it comprises an input and output unit for inputting and displaying various data 2. The voltage detecting unit of claim 1, wherein the voltage detecting unit detects a voltage component of each phase of the three-phase wire and converts the voltage component into a predetermined size, and selects one phase of each voltage component of the three phases converted by the voltage detecting unit. Insulation monitoring system comprising: a phase selector for removing a frequency component above a certain frequency or extracting only a frequency component of a predetermined frequency band from a component of an output value of the phase selector 3. The insulation monitoring system according to claim 2, wherein the voltage detector comprises a series combination of a resistor or a capacitor or a combination of a small capacity transformer and a resistor or a capacitor. The method of claim 1, wherein the leakage current detecting means comprises: a current / voltage conversion unit for converting a leakage current component flowing between the wire path and the ground detected by the image current transformer into a voltage component, and a component converted by the current / current conversion unit. And an amplifying unit configured to amplify a current filter unit for removing a frequency component above a predetermined frequency or extracting only a frequency component of a predetermined frequency band from the leakage current component amplified by the amplifying unit. 2. The apparatus of claim 1, wherein the phase comparing means includes: a voltage component waveform shaping unit for waveform shaping the output value of the voltage detecting unit; a current component waveform shaping unit for waveform shaping the output value of the leakage current detecting unit; And a phase difference detecting unit for detecting a phase difference between the output value of the current component waveform shaping unit and the output value of the current component waveform shaping unit. The apparatus of claim 1, wherein the input / output unit comprises: an input unit having a function of inputting or selecting various data; A display unit for outputting to a display unit such as an LED or a buzzer; And a storage unit having a function of storing various data. The insulation monitoring system according to claim 1, wherein the input / output unit displays a leakage current value or an insulation resistance value flowing between an electric wire path and the ground, and information on a phase in which insulation is poor or good. According to claim 1, Insulation monitoring system further comprises a communication unit for remote monitoring from the outside

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