JP2008140580A - Inrush current suppression device for three-phase transformer - Google Patents

Abstract

By reducing a difference between a steady magnetic flux and a residual magnetic flux, an exciting inrush current is suppressed when a three-phase transformer is turned on simultaneously for all phases.
A magnetizing inrush current suppressing device includes voltage measuring means (11U, 11V, 11W, 13), a residual magnetic flux calculating means (15), a making phase control means (21) and a making command output means (22). The closing phase control means 21 determines the output timing of the closing command for closing the circuit breaker 2 at the target phase, and controls the closing command output means 22. The closing command output means 22 outputs a closing command signal 25 to the circuit breaker operating mechanism 2X. The difference between the steady magnetic flux and the residual magnetic flux is small when both polarities are equal. When the difference between the steady magnetic flux and the residual magnetic flux is small for each of the U phase, the V phase, and the W phase, the transformer as a whole. The difference between the two becomes smaller. The closing phase control means sets the phase range 54 in which the polarities of the steady magnetic flux and the residual magnetic flux of each phase are the same as the target closing phase range of the circuit breaker.
[Selection] Figure 1

Description

  The present invention relates to a device for suppressing an inrush current generated when a circuit breaker is inserted into a three-phase transformer, and particularly suppresses an inrush current without adding an input resistance to the circuit breaker. It is related to the technology.

  When exciting a no-load transformer with a circuit breaker in a state where there is residual magnetic flux in the transformer core, a large excitation inrush current flows, and its magnitude is generally several times the rated load current of the transformer. It is known (for example, refer nonpatent literature 1).

  When such a large magnetizing inrush current flows when the no-load transformer is turned on, problems such as a reduction in power quality due to fluctuations in the system voltage, a reduction in the life of the transformer, and a malfunction of the protection relay may occur.

  In order to suppress this inrush current, there has been conventionally known a method in which a closing resistor is first input using a circuit breaker in which a contact connected in series with a closing resistor is added in parallel with the main contact (for example, a patent) Since the reference resistor and the contact for the input resistor are added to a normal circuit breaker, the circuit breaker cannot be enlarged.

  On the other hand, a method of suppressing excitation inrush current when a direct-grounded three-phase transformer is turned on using three single-phase circuit breakers has already been studied. In that case, it is known that the excitation inrush current can be suppressed by first turning on a one-phase circuit breaker and then turning on the remaining two-phase circuit breakers (see, for example, Patent Documents 2 to 4).

IEEE Transactions on Power Delivery, Vol.16, No.2, April 2001 "Elimination of Transformer Inrush Currents by Controlled Switching-Part I: Theoretical Considerations" JP 2002-75145 A Japanese Patent No. 3804606 JP 2006-40566 A JP 2004-208394 A

  However, as a circuit breaker, there is a three-phase collective operation type circuit breaker in which the operation / opening operation of the three-phase circuit breaker is simultaneously operated by one operation mechanism. When turning on a three-phase transformer using such a three-phase batch operation type circuit breaker, all the phases are turned on at the same time, so apply the magnetizing inrush current suppression device of Patent Documents 2 to 4 above. I can't.

  In the present invention, even when a three-phase transformer is turned on by a three-phase batch operation type circuit breaker, or when all phases are turned on simultaneously by three single-phase type circuit breakers, excitation inrush is performed without adding a closing resistance to the circuit breaker. It aims at providing the apparatus which suppresses an electric current.

  In order to achieve the above object, the present invention provides a magnetizing inrush current suppressing device for controlling a circuit breaker installed between a three-phase transformer and a power source, the voltage of the transformer winding and the transformer. Voltage measuring means for measuring the power supply voltage to be applied; residual magnetic flux calculating means for calculating the magnetic flux of the transformer core by integrating the measured voltage of the transformer winding by the voltage measuring means; and the power supply voltage by the voltage measuring means. Input phase control means for controlling the output timing of the input command to input and input the circuit breaker at the target phase, the residual magnetic flux calculating means, when disconnecting the circuit breaker and disconnecting the transformer from the power source, Based on the measured voltage, the polarity and magnitude of the residual magnetic flux of each phase of the transformer are calculated. When the closing phase control means energizes the transformer by turning on the circuit breaker, the three-phase AC voltage is applied to the transformer. When applied in steady state The phase range in which the phase range where the phase of the steady magnetic flux of the phase and the phase of the residual magnetic flux of each phase of the transformer calculated by the residual magnetic flux calculation means are the same for all three phases is set as the target input phase, and all phases of the circuit breaker Are simultaneously introduced.

  In addition, voltage measurement means for measuring the power supply voltage to be applied to the transformer, interruption phase control means for controlling the output timing of the interruption command to interrupt the breaker at the target phase, and input to introduce the breaker at the target phase A closing phase control means for controlling the output timing of the command, wherein the breaking phase control means shuts off the specific one phase of the transformer when shutting off the breaker and disconnecting the transformer from the power source. The phase control means controls the phase so that the residual magnetic flux of the phase always becomes a constant value. When the circuit breaker is turned on to excite the transformer, the steady magnetic flux of the specific phase of the transformer remains. It is also an aspect of the present invention that all phases of the circuit breaker are turned on at the same time using the voltage phase that intersects the magnetic flux as the target application phase.

  Furthermore, voltage measuring means for measuring the phase voltage or line voltage of the power supply side terminal of the circuit breaker, residual magnetic flux calculating means for calculating the magnetic flux of the transformer core based on the measured voltage by the voltage measuring means, and the voltage measurement And a closing phase control means for controlling the output timing of the closing command to input the circuit breaker at the target phase by inputting the power supply voltage by the means, the residual magnetic flux calculating means powering the transformer by breaking the breaker When disconnecting from the transformer, the polarity and magnitude of the residual magnetic flux of each phase of the transformer is calculated based on the measured voltage, and the closing phase control means turns on the transformer when exciting the transformer by turning on the circuit breaker. The phase range in which the polarity of the steady magnetic flux of each phase when a three-phase AC voltage is applied in a steady state and the polarity of the residual magnetic flux of each phase of the transformer calculated by the residual magnetic flux calculating means is three-phase Overlapping phase range As the target closing phase, also be introduced all phases of the circuit breaker at the same time, which is another aspect of the present invention.

  According to the present invention, it is possible to reduce the difference between the steady magnetic flux and the residual magnetic flux of the transformer as a whole by appropriately selecting the target input phase. Even if they are simultaneously applied, the magnetizing inrush current can be minimized.

(1) First Embodiment (1-1) Configuration of First Embodiment FIG. 1 is a diagram showing a configuration of a magnetizing inrush current suppressing device according to a first embodiment of the present invention.

  The magnetizing inrush current suppressing device 1 of the present embodiment is a device for controlling a three-phase collective operation type circuit breaker 2 installed between a three-phase transformer 3 and a power source 4. The contacts 2U, 2V, 2W of the circuit breaker 2 are all turned on and off simultaneously by the circuit breaker operating mechanism 2X.

  In order to measure the voltages of the U-phase winding 3U, the V-phase winding 3V, and the W-phase winding 3W of the three-phase transformer 3, instrument transformers 5U, 5V, and 5W are connected, respectively. The power source 4 is provided with an instrument transformer 7 for measuring the V-phase voltage.

  The magnetizing inrush current suppression device 1 includes voltage measuring means 11U, 11V, 11W, 13, a residual magnetic flux calculating means 15, a making phase control means 21, and a making command output means 22. The voltage measuring means 11U, 11V, and 11W are connected to instrument transformers 5U, 5V, and 5W, respectively, and a transformer U-phase voltage signal 31U, a transformer V-phase voltage signal 31V, and a transformer W-phase voltage signal 31W, respectively. Is transmitted to the residual magnetic flux calculating means 15.

  The voltage measuring means 13 is connected to the instrument transformer 7 that measures the V-phase voltage of the power supply 4, and transmits the power supply V-phase voltage signal 33 V to the input phase control means 21. The residual magnetic flux calculating means 15 integrates the transformer U-phase voltage signal 31U, the transformer V-phase voltage signal 31V, and the transformer W-phase voltage signal 31W, respectively, so that the U-phase 3U, V-phase 3V, The polarity and magnitude of the residual magnetic flux of each iron core of the W phase 3W are calculated and transmitted to the closing phase control means 21.

  The closing phase control means 21 determines the output timing of the closing command for closing the circuit breaker 2 at the target phase, and controls the closing command output means 22. The closing command output means 22 is composed of a high-speed switch, for example, a semiconductor switch, and outputs a closing command signal 25 to the circuit breaker operating mechanism 2X.

  Here, the transformer U-phase voltage signal 31U, the transformer V-phase voltage signal 31V, and the transformer W-phase voltage signal 31W may be digital signals (sampling data strings) or analog signals. . The residual magnetic flux calculation means 15 applies integration by digital calculation when the signal is a digital signal, and applies an integration circuit when the signal is an analog signal.

(1-2) Operation of the First Embodiment Next, the operation of the magnetizing inrush current suppressing device having the above configuration will be described.

  When the circuit breaker 2 is shut off and the three-phase transformer 3 is disconnected from the power source 4, the transformer U-phase voltage signal 31U, the transformer V-phase voltage signal 31V, and the transformer respectively measured by the voltage measuring means 11U, 11V, and 11W. The W-phase voltage signal 31W is integrated by the residual magnetic flux calculating means 15 to calculate the polarity and magnitude of the residual magnetic flux of each phase iron core of the three-phase transformer.

  The operation of the closing phase control means 21 when the circuit breaker is turned on to excite the three-phase transformer will be described with reference to FIG. FIG. 2 shows an example of the relationship between the power supply phase voltage, the transformer steady-state magnetic flux, and the residual magnetic flux based on the voltage phase of the power supply V-phase.

  The input phase control means 21 first calculates a power U phase voltage signal 33U and a power W phase voltage signal 33W based on the power V phase voltage signal 33V. Since the power supply voltage is normally three-phase balanced, this is achieved by shifting the power supply V-phase voltage signal 33V by 120 ° according to the phase sequence.

  Next, the magnetic flux when the power supply voltage is applied to the three-phase transformer in a steady state, that is, the steady magnetic flux, is integrated with each of the voltage signals 33U, 33V, and 33W, respectively. The calculation is made like a V-phase steady magnetic flux 51V and a transformer W-phase steady magnetic flux 51W. Alternatively, each of the voltage signals 33U, 33V, 33W is usually a sine wave fundamental wave that hardly includes harmonic components and transient waveforms, and may be calculated by simply delaying the phase by 90 °.

  The phase range in which the polarities of the transformer U-phase steady magnetic flux 51U calculated in this way and the residual magnetic flux 52U of the U-phase core shown by the solid line on the + side in the lower graph in FIG. It becomes. Similarly, the phase range in which the polarities are the same for the V phase is 53 V, and the W phase is 53 W.

  That is, the difference between the steady magnetic flux and the residual magnetic flux is small when the polarities of the two are equal. When the difference between the steady magnetic flux and the residual magnetic flux is small for each of the U phase, V phase, and W phase, the transformer The difference between the two as a whole is reduced. Therefore, in the present invention, the closing phase control means sets the phase range 54 where 53U, 53V, 53W all overlap as the target closing phase range of the circuit breaker, thereby obtaining the difference between the steady magnetic flux and the residual magnetic flux as the whole transformer. It is small.

  Here, when a closing command is received from a host control system (not shown), the closing phase control means 21 turns on the breaker contact in the target closing phase range 54 in consideration of the closing operation time and pre-arc time of the breaker. Thus, the input command output means 22 is controlled. The input command output means 22 outputs a cutoff command signal 25 to the circuit breaker operating mechanism 2X.

The above operation will be further described with reference to the timing chart of FIG. The closing phase control means first determines the target closing phase (electrical connection phase) t _make of the circuit breaker so as to match the phase range 54. Next, when the input command from the host control system is received at the timing of t _command , it waits for the timing t _zero of the zero cross point (phase 0 °) of the next power supply V-phase voltage.

Based on this zero cross point timing t _{zero, the} making phase control means calculates the synchronous closing delay time T _delay and transmits it to the making command output means. The closing command output means outputs a closing command signal 25 that is synchronously controlled after the delay time, that is, at the timing of t _control , and drives the closing coil of the circuit breaker operating mechanism 2X.

As a result, the circuit breaker 2 starts the closing operation, and the contacts of the respective contacts 2U, 2V, 2W are mechanically contacted after the closing operation time T _closing , that is, at the timing of t _close . However, the electrical input timing is input at the timing of t _make prior to t _close by the _pre-arc time T _pre-arcing .

Here, ideally, the synchronous closing delay time T _delay includes the time T _target from the zero cross point to the target closing phase, the _pre-arcing time T _pre-arcing corresponding to the target closing phase, and the closing operation time T of the circuit breaker. It is obtained by the following formula using _closing .

T _delay = T _freq + (T _target + T _pre-arcing − (T _closing % T _freq ))
(Where 0 ≦ T _delay <2 · T _freq )
However, (T _closing % T _freq ) represents the remainder of T _closing / T _freq .

The closing operation time T _closing of the circuit breaker varies depending on the control voltage, operation pressure, ambient temperature, operation history, or the like of the circuit breaker. By measuring these factors by means not shown here, it is possible to correct the delay time in the closing phase control means. In such a case, the circuit breaker is more reliably operated in the target closing phase range. Can be inserted. Further, the closing control operation described above is an example, and other control methods for closing the circuit breaker within the phase range 54 of FIG. 2 can be used.

(1-3) Effect of First Embodiment The larger the difference between the steady magnetic flux and the residual magnetic flux when the circuit breaker is turned on, the larger the transformer excitation inrush current. If the peak value of the steady magnetic flux is 1 p.u. and the closing phase of the circuit breaker is not controlled, even if the residual magnetic flux is 0, the maximum difference between the steady magnetic flux and the residual magnetic flux is 1 p.u. It becomes. Theoretically, it is conceivable that the difference reaches a maximum of 2 p.u.

  On the other hand, according to the magnetizing inrush current suppressing device of the present invention, since the transformer is turned on by the above-described operation, the difference between the steady magnetic flux and the residual magnetic flux is smaller than 1 p.u. for each of the U phase, the V phase, and the W phase. Become. Therefore, it can be suppressed to be smaller than the maximum exciting inrush current in the residual magnetic flux 0.

In this embodiment, the winding voltage of each phase of the transformer is measured and the residual magnetic flux is calculated. However, it is also possible to measure the winding voltage for two phases and obtain the remainder by calculation.
On the contrary, when the power supply voltage is not balanced, the accuracy of the phase control can be improved by actually measuring the power supply voltage signals 33U and 33W by 120 ° phase shift instead of obtaining them.

(1-4) Modified Example of First Embodiment In FIG. 1, when a circuit breaker is turned on to excite a three-phase transformer, it is turned on at the voltage zero point of the phase where the residual magnetic flux of the transformer is maximum. Thus, the making phase control means 21 can also be configured.

  This operation will be specifically described with reference to FIG. When the magnitudes of residual magnetic fluxes 52U, 52V, and 52W are compared, the magnitude of the U-phase residual magnetic flux 52U is the largest. When the circuit breaker is turned on, the making phase control means 21 controls the making command output means 22 so that it is turned on at the voltage zero point of the U-phase power supply voltage 33U according to the result. In the case of FIG. 2, since the direction of the residual magnetic flux of 52U is positive, control is performed so that the U-phase power supply voltage 33U is turned on at the zero point (phase 60 ° in FIG. 2) from positive to negative. To do.

  In this case as well, the circuit breaker target application phase enters the phase range 54, and the difference between the residual magnetic flux and the steady magnetic flux is 1 p. It can be made smaller than u. Therefore, the same effect as the first embodiment can be obtained.

(2) Second Embodiment (2-1) Configuration of Second Embodiment FIG. 3 is a diagram showing a configuration of a magnetizing inrush current suppressing device according to a second embodiment of the present invention.

  In the second embodiment, the magnetizing inrush current suppressing device 1 includes a voltage measuring unit 13, a closing phase control unit 21, a closing command output unit 22, a cutoff phase control unit 23, a closing command output unit 24, and a closing phase setting unit 27. Composed.

In the following, different points from the first embodiment will be described.
The voltage measuring unit 13 transmits the power source V-phase voltage signal 33V to the on-phase control unit 21 and the cutoff phase control unit 23. The cutoff phase setting means 27 receives the input of the target cutoff phase of the circuit breaker from the outside and transmits the target cutoff phase to the cutoff phase control means 23.

  The interruption phase control means 23 determines the output timing of an interruption command for breaking the breaker at the target interruption phase, and controls the interruption command output means 24. The break command output means 24 outputs a break command signal 26 to the breaker operating mechanism 2X.

(2-2) Operation of the Second Embodiment Next, the operation of the magnetizing inrush current suppressing device having the above configuration will be described.

  When the circuit breaker is shut off and the three-phase transformer is disconnected from the power source, the shut-off phase control means 23 refers to the power source V-phase voltage signal 33V and makes a target break that maximizes the residual magnetic flux of the transformer V-phase iron core. The shutoff command output means 24 is controlled to shut off at the phase. This target cutoff phase is set in advance by the cutoff phase setting means 27.

  In normal operation, the no-load transformer is shut off, so the circuit conditions at the time of shut-off are always constant. Therefore, the residual magnetic flux of each phase iron core with respect to the power supply voltage phase at the time of interruption is obtained in advance, for example, as shown in FIG. FIG. 4 is a calculation result example of each phase core residual magnetic flux with respect to the cutoff phase with the power source V-phase voltage signal 33V as a phase reference. At this time, the residual magnetic flux 52V of the transformer V-phase iron core can be maximized by setting the cut-off phase setting means 27 so that the power V-phase voltage signal 33V is cut off at a phase of 180 °.

  When the circuit breaker is turned on to excite the three-phase transformer, the making phase control means 21 refers to the power supply V-phase voltage signal 33V so that the circuit breaker is turned on with the voltage phase of 180 ° as the target making phase. The input command output means 22 is controlled. Here, if the transformer winding connected to the circuit breaker is Δ-connected, the point at the phase of 180 ° in the line voltage is set as the target input phase.

(2-3) Effects of the Second Embodiment As described above, to turn on the transformer with a voltage phase that maximizes the residual magnetic flux of the transformer V-phase core at the time of interruption and maximizes the V-phase steady magnetic flux at the time of turning on. The phase where the polarity of the residual magnetic flux of each phase of the transformer is the same is input in a phase range where all three phases overlap.

  In this case, if the V-phase residual magnetic flux is a positive maximum, the U-phase and W-phase residual magnetic fluxes are negative. If the V-phase steady magnetic flux is a positive maximum, the U-phase and W-phase steady magnetic fluxes are negative. Therefore, the same effect as the first embodiment can be obtained.

(2-4) Modified Example of Second Embodiment In FIG. 3, the shutoff command output means 24 can be controlled so as to shut off at a target shutoff phase such that the residual magnetic flux of the transformer V-phase core becomes zero. In the example of FIG. 4, the residual magnetic flux 52V of the transformer V-phase iron core can be substantially zero if it is set to be cut off at the phase 270 ° of the power source V-phase voltage signal.

  In this case, when the circuit breaker is turned on, the making phase control means 21 controls the making command output means 22 so that the circuit breaker is turned on with the voltage phase 270 ° as the target breaking phase.

  As described above, since the residual magnetic flux of the transformer V-phase iron core is almost zero at the time of interruption and the transformer is powered on at a voltage phase where the V-phase steady magnetic flux is almost zero at the time of turning on, each phase of the transformer is also in this case. The phase where the polarities of the residual magnetic fluxes are the same is input in a phase range where all three phases overlap. Therefore, the same effect as the first embodiment can be obtained.

(3) Third Embodiment (3-1) Configuration of Third Embodiment FIG. 5 is a diagram showing a configuration of a magnetizing inrush current suppressing device according to a third embodiment of the present invention.

  In the third embodiment, the magnetizing inrush current suppressing device 1 includes a voltage measuring means 13, a residual magnetic flux calculating means 15, a making phase control means 21, a making command output means 22, and a contact input means 14.

In the following, different points from the first embodiment will be described.
The voltage measuring means 13 transmits the power source V-phase voltage signal 33V to the closing phase control means 21 and the residual magnetic flux calculating means 15. The contact input means 14 is connected to the circuit breaker auxiliary contact 2 </ b> Y and transmits the opening / closing timing of the auxiliary contact to the residual magnetic flux calculation means 15. The residual magnetic flux calculating means 15 calculates the polarity and magnitude of the residual magnetic flux of each phase iron core of the three-phase transformer based on the power source V-phase voltage signal 33V and the auxiliary contact signal 34, and transmits it to the closing phase control means 21. .

(3-2) Operation of Third Embodiment Next, the operation of the magnetizing inrush current suppressing device having the above-described configuration will be described.

  When the circuit breaker is shut off and the three-phase transformer is disconnected from the power source, the power source V-phase voltage signal 33V measured by the voltage measuring means 13 and the remaining phase voltage estimated therefrom are integrated by the residual magnetic flux calculating means 15. The residual magnetic flux of each phase iron core is calculated. The integration period at this time is until the circuit breaker main contact is electrically disconnected and the excitation of the transformer is stopped, and is determined by the time when the circuit breaker auxiliary contact 2Y input by the contact input means 14 is opened. .

  When the circuit breaker is turned on and the three-phase transformer is excited, the turning-on phase control means 21 has a phase range in which the steady-state magnetic flux and the residual magnetic flux have the same polarity in all three phases, as in the first embodiment. Breaker target application phase range.

(3-3) Effect of Third Embodiment With the above operation, the difference between the steady magnetic flux and the residual magnetic flux is smaller than 1 p.u. for each of the U phase, the V phase, and the W phase. Therefore, the magnetizing inrush current can be suppressed to be smaller than the maximum magnetizing inrush current in the residual magnetic flux 0, and the same effect as in the first embodiment can be obtained.

(4) Fourth Embodiment (4-1) Configuration of the Fourth Embodiment FIG. 6 is a diagram showing the configuration of the magnetizing inrush current suppressing device according to the fourth embodiment of the present invention.

  The magnetizing inrush current suppressing device 1 includes a current measuring means 12, a voltage measuring means 13, a residual magnetic flux calculating means 15, a making phase control means 21, and a making command output means 22.

In the following, portions different from the third embodiment will be described.
The current measuring means 12 is connected to the instrument current transformer 6 and transmits the transformer V-phase current to the residual magnetic flux calculating means 15. The residual magnetic flux calculating means 15 calculates the polarity and magnitude of the residual magnetic flux of each phase iron core of the three-phase transformer based on the power source V-phase voltage signal 33V and the transformer V-phase current signal 32V, and the input phase control means Tell to 21.

(4-2) Operation of the Fourth Embodiment Next, the operation of the magnetizing inrush current suppressing device having the above configuration will be described.
When the circuit breaker is shut off and the three-phase transformer is disconnected from the power source, the power source V-phase voltage signal 33V measured by the voltage measuring means 13 and the remaining phase voltage estimated therefrom are integrated by the residual magnetic flux calculating means 15. The residual magnetic flux of each phase iron core is calculated. The integration period at this time is until the circuit breaker main contact is electrically interrupted to stop the excitation of the transformer, and depends on the time when the transformer V-phase current signal 32V measured by the current measuring means 12 becomes zero. judge.

  When the circuit breaker is turned on and the three-phase transformer is excited, the turning-on phase control means 21 has a phase range in which the steady-state magnetic flux and the residual magnetic flux have the same polarity in all three phases, as in the first embodiment. Breaker target application phase range.

(4-3) Effects of Fourth Embodiment With the above operation, the difference between the steady magnetic flux and the residual magnetic flux is smaller than 1 p.u. for each of the U phase, the V phase, and the W phase. Therefore, it can be suppressed smaller than the maximum magnetizing inrush current in the residual magnetic flux 0, and the same effect as the first embodiment can be obtained.

(5) Fifth Embodiment (5-1) Configuration of Fifth Embodiment FIG. 7 is a diagram showing a configuration of a magnetizing inrush current suppressing device according to a fifth embodiment of the present invention.

  The magnetizing inrush current suppressing device 1 includes voltage measuring means 11 and 13, current measuring means 12, residual magnetic flux calculating means 15, making phase control means 21, making command output means 22, and recording means 16.

Hereinafter, a different part from 4th Embodiment is demonstrated.
If a voltage measuring device such as an instrument transformer is not installed at the primary, secondary, or tertiary winding terminal of the transformer to be opened or closed, the portable instrument transformer 8 should be Temporarily connect to the wire terminal.

  The voltage measuring means 11 is connected to the portable instrument transformer 8 and transmits the transformer voltage signal 31 to the residual magnetic flux calculating means 15. The residual magnetic flux calculating means 15 integrates the transformer voltage signal 31 to calculate the polarity and magnitude of the residual magnetic flux in the transformer core, and transmits it to the recording means 16. The recording means 16 can record the value of the residual magnetic flux of the transformer core together with the V-phase voltage phase at the time of interruption. The recorded contents can also be read from the residual magnetic flux calculating means 15.

(5-2) Operation of Fifth Embodiment Next, the operation of the magnetizing inrush current suppressing device having the above-described configuration will be described.
Before operating the transformer, connect the portable instrument transformer 8 to the U phase, shut off the circuit breaker several times, and measure the relationship of the residual magnetic flux of the transformer U phase to the V phase voltage phase at the time of the interruption. To do. The V-phase voltage phase at the time of interruption is determined by the phase at the time when the transformer V-phase current measured by the current measuring means 12 becomes zero. Next, the portable instrument transformer 8 is sequentially connected to the V phase and the W phase, and the same measurement is performed. The relationship between the cutoff phase and the residual magnetic flux thus obtained is recorded in the recording means 16.

Thereafter, the temporarily connected portable instrument transformer 8 is removed, and the operation of the transformer is started.
When operating the transformer, when the circuit breaker is shut off and the three-phase transformer is disconnected from the power source, the residual magnetic flux calculating means 15 uses the V-phase voltage at the time of shut-off from the power source V-phase voltage signal 33V and the transformer V-phase current signal 32V. The voltage phase is obtained, and the value of the residual magnetic flux of each phase of the transformer corresponding to the phase is read from the recording means 16 and transmitted to the closing phase control means 21.

  When the circuit breaker is turned on and the three-phase transformer is excited, the turning-on phase control means 21 has a phase range in which the steady-state magnetic flux and the residual magnetic flux have the same polarity in all three phases, as in the first embodiment. Breaker target application phase range.

(5-3) Effects of Fifth Embodiment By using the relationship recorded in the recording means 16, the polarity of the residual magnetic flux of each phase of the transformer even when the voltage measuring device is not installed at the transformer side terminal during operation And the size can be calculated, and the same effect as the first embodiment can be obtained.

(5-4) Modification of Fifth Embodiment In the fifth embodiment, instead of measuring the transformer winding voltage by a portable instrument transformer, the interruption phase and residual magnetic flux separately calculated by computer simulation or the like are used. The relationship can also be recorded in advance in the recording means 16. Alternatively, a portable instrument transformer may be connected to another device to measure the transformer winding voltage, and the relationship between the circuit breaker phase and the residual magnetic flux obtained therefrom may be recorded in the recording means 16 in advance. it can.

  Even in these cases, the same effect as that of the fifth embodiment can be obtained by using the relationship recorded in the recording unit 16, and the voltage measuring unit 11 in FIG. 7 is not necessary.

(5-5) Another Modification of Fifth Embodiment FIG. 8 is a diagram showing a modification of the fifth embodiment of the present invention. The difference from FIG. 7 is that voltage measuring means for connecting a portable instrument transformer is provided with three circuits of 11U, 11V, and 11W.

  In this embodiment, three portable instrument transformers 8U, 8V, 8W are connected simultaneously, and the circuit breaker is cut off several times, so that the transformer U phase, V phase, The relationship of the residual magnetic flux of W phase is measured simultaneously. As a result, the relationship between the interruption phase and the residual magnetic flux of each phase iron core can be obtained at one time without sequentially changing the connection of the portable instrument transformer.

(5-6) Another Modification of Fifth Embodiment FIG. 9 is a diagram showing a modification of the fifth embodiment of the present invention. The difference from FIG. 7 is that the transformer winding directly connected to the controlled circuit breaker is Δ-connected, and the portable instrument transformer 8 is between the U-V phase, the V-W phase, and the W-U phase. To be connected sequentially.

  In this embodiment, the portable instrument transformer 8 is sequentially connected between the U-V phase, the V-W phase, and the W-U phase of the transformer, and the circuit breaker is shut off several times, so that the V The relationship of the residual magnetic fluxes of the transformer U phase, V phase, and W phase with respect to the phase voltage phase is measured. As a result, when the power supply side winding of the transformer 3 is Δ-connected, the residual magnetic flux can be accurately calculated by directly measuring the winding voltage of each phase with the interphase voltage.

(6) Sixth Embodiment FIG. 10 is a diagram showing a configuration of a magnetizing inrush current suppressing device according to a sixth embodiment of the present invention. In this embodiment, the magnetizing inrush current suppressing device 1 includes a current measuring unit 12, a voltage measuring unit 13, a residual magnetic flux calculating unit 15, a closing phase control unit 21, a closing command output unit 22, and a phase adjusting unit 17. .

  Hereinafter, a different part from 4th Embodiment is demonstrated. The three-phase transformer winding directly connected to the circuit breaker 2 is Δ-connected. The phase adjusting unit 17 shifts the phase of the power source V-phase voltage signal 33V by 30 ° and transmits the phase to the residual magnetic flux measuring unit 15.

  According to the above configuration, the voltage measuring unit 13 directly measures the ground voltage of the power source V phase, but is converted into a V-W phase voltage signal by the phase adjusting unit 17. The residual magnetic flux calculation means 15 obtains the residual magnetic flux of each phase iron core by integrating the voltage signal and the remaining line voltage estimated from the voltage signal until the breaker main contact is electrically interrupted. Therefore, according to this embodiment, the same effect as that of the fourth embodiment can be obtained.

The block diagram of the magnetizing inrush current suppression apparatus of 1st Embodiment of this invention. The figure which shows the circuit breaker target closing phase calculation method of the magnetizing inrush current suppression apparatus of 1st Embodiment of this invention. The block diagram of the magnetizing inrush current suppression apparatus of 2nd Embodiment of this invention. The figure which shows the example of a calculation result of the interruption | blocking phase when a transformer is interrupted | blocked with a circuit breaker, and the residual magnetic flux of each phase. The block diagram of the magnetizing inrush current suppression apparatus of 3rd Embodiment of this invention. The block diagram of the magnetizing inrush current suppression apparatus of 4th Embodiment of this invention. The block diagram of the magnetizing inrush current suppression apparatus of 5th Embodiment of this invention. The figure which shows another structural example of the magnetizing inrush current suppression apparatus of 5th Embodiment of this invention. The figure which shows another structural example of the magnetizing inrush current suppression apparatus of 5th Embodiment of this invention. The block diagram of the magnetizing inrush current suppression apparatus of 6th Embodiment of this invention. The timing chart which shows operation | movement of 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Excitation inrush current suppression apparatus 2 ... 3 phase collective operation type circuit breaker 2U ... Circuit breaker main contact U phase 2V ... Circuit breaker main contact V phase 2W ... Circuit breaker main contact W phase 2X ... Circuit breaker operation mechanism 2Y ... Circuit breaker Auxiliary contact 3 ... 3 phase transformer 3U ... Transformer U phase 3V ... Transformer V phase 3W ... Transformer W phase 4 ... Power supply 5 ... Instrument transformer (for measuring transformer voltage)
6 ... Current transformer for instrument (for measuring transformer current)
7 ... Instrument transformer (for power supply voltage measurement)
8 ... Transportable instrument transformer 8U ... Portable instrument transformer U phase 8V ... Portable instrument transformer V phase 8W ... Portable instrument transformer W phase 11 ... Voltage measuring means (for measuring transformer voltage)
11U ... Voltage measurement means (for measuring transformer voltage U phase)
11V ... Voltage measurement means (for transformer voltage V-phase measurement)
11W ... Voltage measurement means (for transformer voltage W-phase measurement)
12 ... Current measuring means (for measuring transformer current)
13 ... Voltage measuring means (for power supply voltage measurement)
14 ... contact input means 15 ... residual magnetic flux calculation means 16 ... recording means 21 ... making phase control means 22 ... making command output means 23 ... breaking phase control means 24 ... breaking command output means 25 ... making command signal 26 ... breaking command signal 31 ... Transformer voltage signal 31U ... Transformer voltage signal U phase 31V ... Transformer voltage signal V phase 31W ... Transformer voltage signal W phase 32 ... Transformer current signal 33 ... Power supply voltage signal 34 ... Auxiliary contact signal 51U ... Power supply phase voltage U phase 51V ... power supply phase voltage V phase 51W ... power supply phase voltage W phase 52U ... transformer U phase steady magnetic flux 52V ... transformer V phase steady flux 52W ... transformer W phase steady flux 53U ... transformer U phase iron core Residual magnetic flux 53V ... Residual magnetic flux 53W of transformer V-phase iron core ... Residual magnetic flux 54U of transformer W-phase iron core ... Range 54V where the U-phase residual magnetic flux matches the polarity of the steady magnetic flux 54V ... V-phase residual magnetic flux and stationary magnetic flux very Range 55 ... breaker target closing phase range but the polarity of the residual magnetic flux and the steady-state flux of matching range 54W ... W-phase matches

Claims (12)

An inrush current suppression device for controlling a circuit breaker installed between a three-phase transformer and a power source,
Voltage measuring means for measuring the voltage of the transformer winding and the power supply voltage to be applied to the transformer, and residual magnetic flux calculating means for calculating the magnetic flux of the transformer core by integrating the measured voltage of the transformer winding by the voltage measuring means And a closing phase control means for controlling the output timing of the closing command to input the power supply voltage by the voltage measuring means and to turn on the circuit breaker at the target phase,
The residual magnetic flux calculating means calculates the polarity and magnitude of the residual magnetic flux of each phase of the transformer based on the measured voltage when the circuit breaker is disconnected and the transformer is disconnected from the power source.
The turning-on phase control means is configured such that when a circuit breaker is turned on and a transformer is excited, a three-phase AC voltage is applied to the transformer in a steady state, and the residual magnetic flux of each phase The phase range in which the phase ranges in which the residual magnetic flux of each phase of the transformer calculated by the calculation means is the same is a phase range in which all three phases overlap, and all phases of the circuit breaker are simultaneously input. Inrush current suppression device for phase transformer. An inrush current suppression device for controlling a circuit breaker installed between a three-phase transformer and a power source,
Voltage measuring means for measuring the voltage of the transformer winding and the power supply voltage to be applied to the transformer, and residual magnetic flux calculating means for calculating the magnetic flux of the transformer core by integrating the measured voltage of the transformer winding by the voltage measuring means And a closing phase control means for controlling the output timing of the closing command to input the power supply voltage by the voltage measuring means and to turn on the circuit breaker at the target phase,
The residual magnetic flux calculating means calculates the polarity and magnitude of the residual magnetic flux of each phase of the transformer based on the measured voltage when the circuit breaker is disconnected and the transformer is disconnected from the power source.
When the circuit breaker is turned on to excite the transformer, the closing phase control means simultaneously turns on all phases of the circuit breaker with the voltage zero point of the phase having the maximum residual magnetic flux as the target closing phase. A three-phase transformer excitation inrush current suppression device characterized by the above. An inrush current suppression device for controlling a circuit breaker installed between a three-phase transformer and a power source,
Voltage measuring means for measuring the power supply voltage to be applied to the transformer, interruption phase control means for controlling the output timing of the interruption command for breaking the breaker at the target phase, and an input instruction for turning on the breaker at the target phase And a closing phase control means for controlling the output timing,
When the circuit breaker is disconnected and the transformer is disconnected from the power source, the specific phase of the transformer is interrupted at a specific voltage phase so that the residual magnetic flux of the phase always has a substantially constant value. Control
The closing phase control means sets the voltage phase at which the specific one-phase steady-state magnetic flux of the transformer substantially intersects the residual flux when the transformer is excited by turning on the breaker as a target closing phase. An inrush current suppression device for exciting a three-phase transformer, wherein the phases are input simultaneously. The breaking phase control means breaks the breaker at a voltage phase at which the magnitude of the residual magnetic flux is maximum for a specific phase of the transformer,
4. The excitation inrush current suppressing device for a three-phase transformer according to claim 3, wherein the closing phase control means sets the voltage zero point of the specific one phase of the transformer as a target closing phase. The breaking phase control means breaks the breaker at a voltage phase at which the magnitude of the residual magnetic flux is minimized for a specific phase of the transformer,
4. The excitation inrush of the three-phase transformer according to claim 3, wherein the input phase control means sets a voltage phase at which the steady magnetic flux of the specific one phase of the transformer substantially intersects with the residual magnetic flux as a target input phase. Current suppression device.   The phase voltage or the line voltage of the transformer winding is measured only in two quantities, and the polarity and magnitude of the residual magnetic flux or steady magnetic flux of each phase of the transformer are calculated based on the voltage. 3. A magnetizing inrush current suppressing device for a three-phase transformer according to claim 1 or 2. An inrush current suppression device for controlling a circuit breaker installed between a three-phase transformer and a power source,
Residual magnetic flux calculating means for calculating the magnetic flux of the transformer core based on the phase of the voltage at which the breaker breaks, and the output timing of the closing command for inputting the power supply voltage by the voltage measuring means and turning on the breaker at the target phase And a closing phase control means for controlling
The residual magnetic flux calculating means calculates the polarity and magnitude of the residual magnetic flux of each phase of the transformer based on the measured voltage when the circuit breaker is disconnected and the transformer is disconnected from the power source.
The turning-on phase control means is configured such that when a circuit breaker is turned on and a transformer is excited, a three-phase AC voltage is applied to the transformer in a steady state, and the residual magnetic flux of each phase The phase range in which the phase ranges in which the residual magnetic flux of each phase of the transformer calculated by the calculation means is the same is a phase range in which all three phases overlap, and all phases of the circuit breaker are simultaneously input. Inrush current suppression device for phase transformer.   8. The inrush of a three-phase transformer according to claim 7, wherein the circuit breaker disconnects the transformer from the power source and determines when the voltage application to the transformer stops based on the auxiliary contact input of the circuit breaker. Current suppression device.   The inrush of the three-phase transformer according to claim 7, wherein the circuit breaker disconnects the transformer from the power source and determines when the voltage application to the transformer stops based on the phase current measurement of the transformer. Current suppression device. Voltage measuring means for measuring both the power supply side terminal voltage and the transformer side terminal voltage of the circuit breaker,
When the circuit breaker is shut off and the transformer is disconnected from the power supply, the relationship between the interruption phase measured by the power supply terminal voltage and the polarity and magnitude of the residual magnetic flux obtained by integrating the transformer terminal voltage waveform Comprising recording means for recording,
The polarity and the magnitude of the residual magnetic flux of each phase of the transformer are calculated using the relationship recorded in the recording means, even when the transformer side terminal voltage is not measured. The excitation inrush current suppression device for a three-phase transformer according to any one of the above. A recording means for inputting and recording the relationship between the phase at the time of disconnection when the circuit breaker is disconnected and the transformer is disconnected from the power source, and the polarity and magnitude of the residual magnetic flux of the transformer from the outside of the device,
The residual magnetic flux calculating means calculates the polarity and magnitude of the residual magnetic flux of each phase of the transformer without measuring the transformer side terminal voltage, using the relationship recorded in the recording means. The apparatus for exciting inrush current of a three-phase transformer according to any one of claims 7 to 9. The transformer winding cut off by the circuit breaker is a Δ connection, and the transformer side terminal voltage or the power supply side terminal voltage to be measured is a phase voltage, and phase adjustment means for this phase voltage-line voltage conversion With
The said residual magnetic flux calculation means calculates the polarity and magnitude | size of the residual magnetic flux of each phase of a transformer based on the voltage after the phase adjustment by the said phase adjustment means, The Claim 1, Claim 2 or Claim characterized by the above-mentioned. 7. A magnetizing inrush current suppressing device for a three-phase transformer according to item 7.

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