JP4495030B2 - Closed phase control device for switchgear - Google Patents

Description

  In the present invention, when power is turned on to a phase-advanced load circuit (corresponding to a capacitor bank with a neutral point grounded or an unloaded transmission line) connected to a power supply side circuit via a three-phase switchgear. The present invention relates to a closing phase control device for a switchgear that controls the closing phase so as to minimize the generation of transient voltage and current associated with the closing operation.

  Conventionally, when power is supplied to this phase-advancing load circuit, the power supply voltage of each phase is measured, the power supply voltage zero point for each phase is detected, and the circuit breaker for each phase is set near the power supply voltage zero point. There has been a phase control switchgear that suppresses generation of transient voltage and current to a minimum by individually turning on (see, for example, Patent Document 1).

International Publication No. W000 / 04564 (Embodiment 13, FIG. 1, FIG. 2, FIG. 3, etc.)

  In general, it is difficult to measure DC voltage due to residual charges remaining on capacitors and transmission lines when the phase advance load circuit is cut off. Therefore, in conventional phase control switchgear, power is supplied to this phase advance load circuit. In doing so, the circuit breaker closing phase is controlled by paying attention only to the power supply voltage of each phase. For this reason, considering the dielectric strength characteristics between the circuit breaker poles during the circuit breaker closing process, even if the circuit breaker is closed at the zero point of the power supply voltage, if the charge remains on the capacitor or the transmission line at the time of the circuit break, In addition to the power supply voltage, a DC voltage due to residual charge is superimposed between the circuit poles, so depending on the polarity of the power supply voltage zero point that closes the circuit breaker, the circuit breaker is electrically connected with a high phase voltage. In some cases, overvoltage and overcurrent could not be sufficiently suppressed.

  The present invention has been made to solve the above-described problems, and is a switchgear that can always suppress the generation of a transient voltage and current accompanying the closing operation of a phase-advancing load circuit to a minimum. An object of the present invention is to provide a closed phase control apparatus.

A closing phase control device for a switchgear according to the present invention is a power supply side voltage measuring unit that measures each phase voltage of a power supply side circuit and detects a cycle of a voltage zero point of each phase voltage, and starts opening operation of a three-phase switchgear. Residual voltage polarity estimation means that estimates and holds the polarity of each phase residual voltage of the phase-advancing load circuit from the circuit information measurement value until the completion of the post-opening operation, and operates based on the closing command of the three-phase switchgear, voltage zero point A closed phase control unit that controls the closed phase of each phase so that the voltage polarity is closed at the voltage zero point that reverses the polarity of the residual voltage held at the zero point to the opposite polarity. is there.

As described above, each phase is closed at the voltage zero point that reverses the polarity of the residual voltage of the phase-advanced load circuit estimated from the circuit information measurement value from the start of the opening operation until the completion of the opening operation to the opposite polarity. Since it has a closed phase control unit that controls the closed phase, even if it is electrically turned on before the mechanical closing time due to the inter-electrode insulation characteristics of the switchgear, it is always turned on with a low voltage between the contacts. As a result, the generation of transient voltage and current can be reliably suppressed to a minimum.

Embodiment 1 FIG.
1 is a block diagram showing a configuration of a closing phase control device of a switchgear according to Embodiment 1 of the present invention. Note that FIG. 1 illustrates all the components necessary for each embodiment, as can be referred to in the description of Embodiments 2 and 3 described later.
In FIG. 1, a circuit breaker 10 includes a phase advance load 1R, 1S, 1T corresponding to a capacitor bank with a neutral point grounded or an unloaded transmission line shown on the left side of the figure, and a power supply side circuit on the right side of the figure. Connected between and. The circuit breaker 10 includes operation devices 12R, 12S, and 12T that are independent of each other so that the contacts in the arc extinguishing chambers 11R, 11S, and 11T can be opened and closed independently.

  On the power source side of the circuit breaker 10, voltage measuring units 13R, 13S, and 13T that measure the power source side voltage of each phase, which are used in any of the embodiments, are provided. Further, on the load side of the circuit breaker 10, voltage measuring units 14R, 14S, and 14T that are used in the first embodiment and that measure the load side voltage of each phase are provided. Furthermore, current measuring units 15R, 15S, and 15T that measure each phase current of the circuit breaker 10 used in the second embodiment to be described later are provided.

  The phase control opening / closing arithmetic processing unit 20 is configured by a computer or the like and performs arithmetic processing including closing phase control. The phase control opening / closing arithmetic processing unit 20 operates based on outputs from the voltage measuring units 13R, 13S, and 13T, and a voltage A load voltage detection unit 22 that operates based on outputs from the measurement units 14R, 14S, and 14T, a current detection unit 23 that operates based on outputs from the current measurement units 15R, 15S, and 15T, and the detection units 21, 22, 23 And an arithmetic / operation control unit 24 that operates based on the output from the open / close pole signal 30. The calculation / operation control unit 24 includes a residual voltage polarity estimation unit 25 and a closing phase control unit 26 as functions.

The operation of the closing phase control device for the switchgear according to Embodiment 1 of the present invention will be described below. First, the operation of the residual voltage polarity estimation means 25 for estimating the polarity of the residual voltage due to the interruption of the phase-advancing load will be described with reference to FIG. That is, the phase advance load remains even after the voltage at the time of interruption is interrupted due to the presence of the capacitance. Prior to the closing operation of the circuit breaker 10, the present invention estimates the residual voltage polarity of each phase at the time of previous interruption, and based on the residual voltage polarity, the transient voltage and current can be suppressed. The polar phase is obtained by calculation.
2 is created in consideration of the description in Embodiments 2 and 3 to be described later, as in FIG.

  FIG. 2A shows the power supply side voltage of each phase output from the voltage measuring units 13R, 13S, and 13T. This output is transmitted to the reference phase detector 21, and the voltage phase of each phase is detected. This point will be described in more detail at the closing phase controller 26 described later. FIG. 2B shows the load side voltage of each phase output from the voltage measuring units 14R, 14S, and 14T. FIG. 2C shows the gradient of the load side voltage obtained by time differentiation (dv / dt) of the load side voltage taken in via the load voltage detection unit 22 by the residual voltage polarity estimation means 25. Then, the residual voltage polarity estimation means 25 detects a point in time when the slope of the load side voltage of each phase becomes equal to or less than a predetermined threshold, and reads and holds the load side voltage at the detection point ((b) in the figure). . The residual voltage polarity can be easily estimated from the polarity of the load side voltage.

  In the example of FIG. 2, in the R phase, the slope of the voltage is less than or equal to the threshold value near the point indicated as the R phase cutoff point, and the residual voltage in the R phase is negative due to the polarity of the load side voltage at that point. It is determined that there is. Similarly, in the S phase, the slope of the voltage is less than or equal to the threshold value near the time point indicated as the latest S phase cutoff point, and the residual voltage of the S phase is negative due to the polarity of the load side voltage at that time. It is determined. In the T phase, the slope of the voltage is below the threshold value near the time point indicated as the T phase cutoff point, and the residual voltage of the T phase is determined to be positive from the polarity of the load side voltage at that time point.

  In addition, FIG.2 (d) shows each phase voltage which appears between the poles after circuit breaker 10 interruption | blocking for reference. FIG. 2E shows each phase current at the time of interruption, and is referred to in the second and third embodiments.

Next, the operation of the closing phase control unit 26 that obtains the closing phase using the data of the residual voltage polarity of each phase after the opening operation obtained as described above will be described.
In the present invention, among the voltage zero points of the power supply side voltage, the voltage polarity is set as a target phase that closes the phase of the voltage zero point at which the polarity of the residual voltage is reversed to the reverse polarity at the voltage zero point. First, the operation principle will be described with reference to FIG.
FIG. 3 illustrates, for example, the operation at the time of closing when the R phase in FIG. 2 is taken as an object. In particular, since both the poles of the circuit breaker are in mechanical contact (in the figure, the points T1 and T2 correspond) and the dielectric strength between the poles is finite, the poles are usually in mechanical contact. A closing point where both poles are electrically energized before the closing point is indicated (points A and B correspond in the figure).

  In FIG. 3, the load-side voltage at the lower end is the R-phase, and thus negative-polarity residual voltage in this example. The power supply side voltage shows a sinusoidal waveform with the voltage zero as the baseline, and there are two types of voltage zeros. That is, the voltage polarity is the phase T2 point of the voltage zero point that reverses from the polarity of the residual voltage (here negative polarity) to the opposite polarity (here positive polarity) at the voltage zero point, and the voltage zero point not corresponding to the above, There is a voltage zero point T1 at which the voltage polarity reverses from the opposite polarity (positive polarity here) to the residual voltage polarity (negative polarity here) at the voltage zero point.

In FIG. 3, the sine wave waveform at the upper end indicates the breaker pole voltage obtained by subtracting the load side voltage from the power source side voltage. The dotted lines extending from the points T1 and T2 to the upper left are dielectric strength curves between the poles in the circuit breaker closing process. When the circuit breaker is operated to mechanically close at the points T1 and T2, respectively. It shows the dielectric strength between electrodes (RDDS). Therefore, the intersection of this breaker pole-to-pole voltage curve and the dielectric strength-to-pole curve is the electrical input point when operated at each closed phase (points A and B in the figure correspond), The position on the horizontal axis of both points is the input phase, and the position on the vertical axis of both points is the magnitude of the inter-electrode applied voltage when the inter-electrode insulation is broken. Since this breakdown voltage is an initial value of a transient phenomenon that is started by turning on, the larger the breakdown voltage, the greater the influence on the power system and the like.
As is clear from FIG. 3, by setting a voltage zero point (in FIG. 3, the point T2 corresponds) that reverses the polarity of the residual voltage due to the opening to the opposite polarity as the closing phase, the electrical input Is performed at the point B where the voltage between the electrodes becomes a lower voltage, so that the generation of transient voltage and current due to the input is always suppressed to the minimum.

Next, a specific control operation for setting a voltage zero point that reverses the polarity of the residual voltage due to opening to the opposite polarity for each phase will be described with reference to FIG.
FIG. 4 is a timing chart showing the closing control operation in the R phase. Although the specific closing timing for the other S phases and T phases is different from that for the R phase, the procedure for the closing control operation is exactly the same, and the other phases are not shown.
(A), (b), and (c) are respectively the R-phase power supply side voltage, the R-phase load side voltage, and the residual voltage and the power supply side voltage at the time of opening determined by the residual voltage polarity estimation means 25 previously. The R-phase electrode voltage obtained from The reference phase detection unit 21 detects the cycle of the voltage zero point from the voltage value measured by the voltage measurement unit 13R. This corresponds to Tori, Tori + 1, Tori + 2,... In FIG.

  When an input command is received ((g) in the figure), the R phase voltage zero point that first appears after the elapse of time tcal required for the following series of calculation operations is set as the reference point TRstandard (a). The closing phase control unit 26 separately obtains measurement data of the ambient temperature, operation pressure, and control voltage of the operation devices 12R, 12S, and 12T, and calculates the R-phase closing operation time trclose of the circuit breaker 10 predicted from these data. calculate. Then, after the lapse of the R-phase closing operation time trclose from the reference point TRstandard, a voltage zero that first appears and reverses from the polarity of the residual voltage to the opposite polarity is detected, and the voltage zero is set as the R-phase closing target point TRtarget.

Then, an operation synchronization time trcont is calculated by subtracting the R phase closing operation time trclose from the R phase closing target point TRtarget so that the closing operation is actually performed at the R phase closing target point TRtarget (f). .
Based on the above calculation results, the closing phase control unit 26 sends a closing signal to the controller device 12R after the operation synchronization time trcont has elapsed from the reference point TRstandard. This ensures that the closing operation is performed at the timing of the R-phase closing target point TRtarget. FIG. 4E shows the operation of the drive mechanism in the arc extinguishing chamber 11R. In this case, due to the inter-electrode dielectric strength characteristics, the electric charging is performed at a timing before the leading arc time trprearc from the timing of the R-phase closing target point TRtarget ((d) in the figure). As described in FIG. 3, the input voltage is lower and the transient voltage and current are sufficiently suppressed.
As described above, since the closing operation of the other phases S and T is performed in exactly the same manner as the R phase, the description will be omitted. The transient voltage and current are sufficiently suppressed.

Embodiment 2. FIG.
Since only the operation of the residual voltage polarity estimation means 25 is different from the first embodiment, only this part will be described below.
In the residual voltage polarity estimation means 25 of the second embodiment, the information on the power supply side voltage (FIG. 2 (a)) that is input through the reference phase detection unit 21 and the output of the voltage measurement units 13R, 13S, and 13T, and the current measurement The residual voltage polarities of the respective phases accompanying the opening operation are estimated based on the information on the circuit breaker current (FIG. 2 (e)) inputted from the outputs of the units 15R, 15S, and 15T through the current detection unit 23.
That is, after the circuit breaker 10 receives the opening command, the voltage polarity of each phase power supply side voltage measurement value at the time when each phase circuit breaker current measurement value becomes a predetermined threshold value or less is estimated as the residual voltage polarity as it is. Can do.

  Referring to the example of FIG. 2, the current value of the R phase becomes equal to or less than the threshold when it is marked as the R phase cutoff point, and the residual voltage of the R phase is determined to be negative from the polarity of the power supply side voltage at that time. Is done. Similarly, the current value of the S phase becomes equal to or less than the threshold when it is marked as the latest S phase cutoff point, and the residual voltage of the S phase is determined to be negative from the polarity of the power supply side voltage at that time. The In addition, the current value of the T phase becomes equal to or less than the threshold when it is marked as the T phase cutoff point, and the T phase residual voltage is determined to be positive from the polarity of the power supply side voltage at that time.

  Since the operation of the closing phase control unit 26 that controls the closing phase based on the residual voltage polarity of each phase estimated by the residual voltage polarity estimation means 25 is the same as that in the first embodiment, the description thereof is omitted. However, even in the second embodiment, the generation of transient voltage and current accompanying the closing operation can be surely suppressed to the minimum.

Embodiment 3 FIG.
Since only the operation of the residual voltage polarity estimation means 25 is different from the first and second embodiments, only this part will be described below.
The residual voltage polarity estimation means 25 of the third embodiment includes an opening phase control unit that controls the opening phase when the circuit breaker 10 receives an opening command, and regulates the residual voltage polarity associated with opening. Thus, the residual voltage polarity data is obtained.

The reference phase detection unit 21 detects the cycle of the voltage zero point from the voltage values measured by the voltage measurement units 13R, 13S, and 13T. When the circuit breaker 10 receives an opening command, the opening phase control unit of the residual voltage polarity estimation means 25 considers the interruption time of each phase, and each of the arc extinguishing chambers 11R, 11S, 11T Each contactor performs an opening operation at a predetermined electrical angle, and gives an opening signal to each phase operating device 12R, 12S, 12T so that the current is interrupted at the positive or negative wave crest of the voltage of each phase. Control timing.
For example, as shown in FIG. 2, the opening signal to be supplied to each phase operating device 12R, 12S, 12T so as to cut off the current at the negative wave crest point of the R phase voltage as the arbitrarily set first breaking phase. When the timing is controlled and each contact in each of the arc extinguishing chambers 11R, 11S, and 11T performs the opening operation at a predetermined electrical angle and the current is cut off, the current is cut off at the negative wave height of the voltage. The controlled residual voltage of the R phase is negative. Since the second interrupted phase and the third interrupted phase are interrupted at the zero current point that reaches the electrical angle interval of 60 ° after the first phase is interrupted, the current is interrupted by the positive polarity of the T phase, which is the second interrupted phase. Therefore, the residual voltage of the T phase is positive. The S phase that is the third cutoff phase is negative in voltage and current is interrupted, so the residual voltage in the S phase is negative.

In this way, by controlling the opening phase of the circuit breaker 10 to cut off the current, the three phases including the other two phases are determined from the polarity of the voltage crest point at which the current is cut off in the arbitrarily set first breaking phase. The polarity of all residual voltages is predictable.
If phase control for setting the cutoff phase to the voltage peak point is performed for all three phases, the control becomes complicated, but the residual voltage polarity can be estimated with higher accuracy.

  Since the operation of the closing phase control unit 26 that controls the closing phase based on the residual voltage polarity of each phase estimated by the residual voltage polarity estimation means 25 is the same as that in the first embodiment, the description thereof is omitted. However, also in the third embodiment, the generation of transient voltage and current accompanying the closing operation can be surely suppressed to the minimum.

  The closing phase control device of the switchgear according to the present invention can be widely applied to various switchgears that open and close a phase-advancing load, and reliably suppress the generation of transient voltage and current accompanying the closing operation. can do.

It is a block diagram which shows the structure of the closing phase control apparatus of the switchgear in this invention. It is a figure for demonstrating operation | movement of the residual voltage polarity estimation means 25 in this invention, and shows each voltage and current waveform at the time of phase-advanced load circuit interruption | blocking. It is a figure for demonstrating the principle of operation of the closing phase control part 26 in this invention. 4 is a timing chart showing a specific control operation of the closing phase control unit 26 in the present invention.

Explanation of symbols

1R, 1S, 1T phase advance load, 10 circuit breaker,
13R, 13S, 13T voltage measurement unit, 14R, 14S, 14T voltage measurement unit,
15R, 15S, 15T current measurement unit, 20 phase control opening / closing operation processing unit,
21 reference phase detector, 22 load voltage detector, 23 current detector,
24 arithmetic / operation control unit, 25 residual voltage polarity estimation means, 26 closing phase control unit.

Claims (4)

In the closing phase control device of the switching device that controls the closing phase of the three-phase switching device connected between the power supply side circuit and the phase-advancing load circuit,
A power supply side voltage measurement unit that measures each phase voltage of the power supply side circuit and detects a cycle of the voltage zero point of each phase voltage, and circuit information measurement values from the start of the opening operation of the three-phase switchgear to the completion of the opening operation From the residual voltage polarity estimation means for estimating and holding the polarity of each phase residual voltage of the phase advance load circuit, and the closing command of the three-phase switchgear, and the voltage polarity of the voltage zero point is What is claimed is: 1. A switchgear comprising a closing phase control unit for controlling a closing phase of each of the phases so as to be closed at a voltage zero point that reverses the polarity of the residual voltage held at the zero point to a reverse polarity thereof. Closed phase control device. The residual voltage polarity estimation means includes a load-side voltage measurement unit that measures each phase voltage of the phase-advancing load circuit, and after the three-phase switchgear receives an opening command, each phase load-side voltage measurement value 2. The closing phase of the switchgear according to claim 1, wherein the voltage polarity of each phase load side voltage measurement value at the time when the time differential value of the phase becomes equal to or less than a predetermined value is estimated as the phase residual voltage polarity. Control device. The residual voltage polarity estimation means includes a current measuring unit that measures each phase current flowing through the three-phase switchgear, and after the three-phase switchgear receives an opening command, each phase current measurement value is a predetermined value. 2. The closing phase control device for a switchgear according to claim 1, wherein a voltage polarity of each phase power supply side voltage measurement value at a time point below becomes estimated as each phase residual voltage polarity. When the three-phase switchgear receives an opening command, the residual voltage polarity estimation means is configured to open the phase of each phase so as to cut off the current at the positive or negative wave crest of the power supply side voltage measurement value. 2. The switchgear according to claim 1, further comprising: an opening phase control unit configured to control a voltage polarity of each phase power supply side voltage measurement value at the time of current interruption as the phase residual voltage polarity. Closed phase control device.

Images