JP2007205785A - Voltage measuring device of power apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage measuring device of a power apparatus, which dispenses with a replacement work of a low-voltage side capacitor circuit and with a mounting work for capacitor addition. <P>SOLUTION: This voltage measuring device 20 is equipped with an adjustment circuit 60 including a plurality of adjustment capacitors for voltage adjustment. The adjustment circuit 60 is equipped with terminals for a jumper by which a composite capacitor comprising one or two or more combinations of the plurality of adjustment capacitors can be connected in parallel to the second capacitor circuit 25, and also is equipped with a jumper socket for connecting the terminals. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a voltage measuring device for power equipment.

  Conventionally, Patent Document 1 is known as a voltage measurement device that is mounted on a power device and detects a phase voltage of a distribution line. The voltage measuring device of Patent Document 1 is configured to measure voltage by a capacitor voltage dividing method, and specifically, a capacitor series circuit in which a high voltage side capacitor and a low voltage side capacitor are connected in series with each other is used. It has been. The phase voltage is input to both ends of this capacitor series circuit and divided according to the ratio of the capacitance of the high voltage side capacitor and the capacitance of the low voltage side capacitor. This is performed based on the divided voltage divided by the low voltage side capacitor.

  FIG. 1 shows a series circuit of a pair of capacitor circuits 100 and 200 included in a capacitor voltage dividing type voltage measuring apparatus. In FIG. 1, for convenience of explanation, only a circuit portion that performs voltage measurement for one phase is shown. Hereinafter, the capacitor circuit 100 is referred to as a high voltage side capacitor circuit, and the capacitor circuit 200 is referred to as a low voltage side capacitor circuit.

  In the figure, one terminal of both terminals of the series circuit is an input terminal T100 connected to the one-phase distribution line L, the other terminal is grounded, and the first output terminal T110. It is said that. The connection point between the high voltage side capacitor circuit 100 and the low voltage side capacitor circuit 200 is connected to the second output terminal T120.

If the voltage (phase voltage) of the distribution line L is Vin, the divided output Vout between the first output terminal T110 and the second output terminal T120 output terminal is
Vout = {Ca / (Ca + Cb)} Vin
It becomes. Ca is the capacitance of the high voltage side capacitor circuit 100, and Cb is the capacitance of the low voltage side capacitor circuit 200.

The partial pressure ratio is as follows.
Partial pressure ratio = Ca / (Ca + Cb)
Japanese Patent No. 3632920

By the way, in order to perform the voltage measurement with high accuracy, it is necessary to adjust the capacitance of the capacitor with high accuracy.
Conventionally, in order to set the divided output Vout as a target value, an operator actually attaches a series circuit including a high-voltage side capacitor circuit 100 and a low-voltage side capacitor circuit 200 to a power device such as a switch, The partial pressure output Vout is measured. If the measured value does not reach the target value, the operator replaces the low voltage side capacitor circuit 200 so that the measured value becomes the target value, or replaces the capacitor with a small capacitance with the low voltage side capacitor circuit. It can be attached to 200 in parallel. It is necessary to replace the low voltage side capacitor circuit 200 or attach a capacitor having a small capacitance.

  As described above, the reason why the measured value does not reach the target value is that the low voltage side capacitor circuit 200 is often mounted on the circuit board, and the lead wire connecting the high voltage side capacitor circuit 100 and the low voltage side capacitor circuit 200. This is because the device-specific capacitance such as the capacitance of the circuit board or the capacitance of the circuit board is connected in parallel with the low-voltage side capacitor circuit 200. For this reason, there is a slight deviation in the actual voltage division ratio with respect to the target voltage division ratio.

  As described above, conventionally, in order to eliminate the deviation of the voltage division ratio, the replacement of the low voltage side capacitor circuit 200 or the work of mounting a capacitor having a small capacitance in parallel to the low voltage side capacitor circuit 200 There was a problem that was necessary.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a voltage measuring device for power equipment that does not require replacement work for a low-voltage side capacitor circuit or mounting work for adding a capacitor. Is to provide.

  According to the first aspect of the present invention, there is provided a voltage measuring device for a power device in which a pair of capacitor circuits are connected in series and a phase voltage can be measured by a divided output of one capacitor circuit. The adjustment circuit includes a connection terminal that can be connected in parallel with the one capacitor circuit, and a connection terminal is connected between the connection terminals. A gist of a voltage measuring apparatus for electric power equipment, characterized in that it is provided with connecting means. Note that the combination of capacitors includes a parallel connection of capacitors and a series connection of capacitors.

According to a second aspect of the present invention, in the first aspect, the adjustment capacitor includes a temperature compensation capacitor.
According to a third aspect of the present invention, in the second aspect, the temperature compensating capacitor is a polyester film capacitor.

According to a fourth aspect of the present invention, in the first aspect, the adjustment capacitor is a ceramic capacitor.
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the connection means is a jumper socket capable of jumper connection.

  According to the first aspect of the present invention, since the composite capacitor comprising a combination of a plurality of adjustment capacitors has a terminal that can be connected in parallel with one capacitor circuit, the capacitor circuit that measures the phase voltage in the temporary connection. If the output voltage is compared with the reference voltage and does not match the reference voltage, the connection is changed, and the connection terminal at the reference voltage is connected. This makes it possible to accurately measure the phase voltage connected to the power device. Note that “being at the reference voltage” includes both cases where the reference voltage completely matches the reference voltage and within the allowable accuracy range. According to the first aspect of the present invention, there is an effect that the replacement work of the low voltage side capacitor circuit and the mounting work for adding the capacitor are not required.

  According to the second aspect of the invention, the temperature compensation capacitor is included in the adjustment capacitor, so that the rate of temperature change of the voltage division ratio can be reduced, thereby accurately measuring the phase voltage connected to the power equipment. it can.

According to the invention of claim 3, the effect of claim 2 can be easily realized by using a polyester film capacitor as the temperature compensation capacitor.
According to the invention of claim 4, the effect of claim 1 can be easily realized by using a ceramic capacitor as the adjustment capacitor.

  According to the invention of claim 5, by making the connecting means a jumper socket, the temporary connection and the main connection of the adjusting capacitor can be easily performed.

Hereinafter, an embodiment in which the present invention is embodied in a voltage measuring device for a switch as a power device will be described with reference to FIGS.
As shown in FIG. 3, the switch 10 is provided for each of the U, V, and W phases of the distribution line L and is capable of turning on and off the power transmission of the distribution line L of each phase, A voltage measuring device 20 that measures the voltage of the distribution line L is provided.

As shown in FIG. 4, the voltage measurement device 20 includes voltage detection circuits 21 to 23 for detecting voltages Vu, Vv, and Vw of the U-phase, V-phase, and W-phase distribution lines L.
A control device 30 is connected to the switch 10, and the control device 30 controls the opening and closing of the signal processing unit 26 that performs signal processing and the switching unit 10 a based on the voltage measurement result of the voltage measuring device 20. And a control unit 27.

Since the voltage detection circuits 21 to 23 have the same configuration, the configuration of the voltage detection circuit 21 will be representatively described below.
When the voltage detection circuit 21 detects the U-phase voltage Vu of the distribution line L, its input terminal T10 is connected to the U-phase line. The other input terminal T20 is grounded via a neutral wire (not shown), and the U-phase voltage Vu is input between the input terminals T10 and T20.

The same applies to the voltage detection circuits 22 and 23, and the V-phase and W-phase voltages Vv and Vw of the distribution line L can be input to the voltage detection circuits 22 and 23, respectively.
As shown in FIGS. 2 and 4, the voltage detection circuit 21 includes a first capacitor circuit 24, a series circuit of the second capacitor circuit 25, and an adjustment circuit 60 connected in parallel to the second capacitor circuit 25. In the present embodiment, the first capacitor circuit 24 corresponds to a high voltage side capacitor circuit, and the second capacitor circuit 25 corresponds to a low voltage side capacitor circuit. In the present embodiment, the first capacitor circuit 24 includes a single capacitor 51. As the capacitor 51, for example, a ceramic capacitor is used.

  The second capacitor circuit 25 includes a capacitor 52. In FIG. 4, the adjustment capacitor is denoted by reference numeral 53 and the terminals J1 to J3 are omitted for convenience of explanation. The capacitor 52 is composed of a single capacitor, for example, a ceramic capacitor. Further, the capacitance C52 of the capacitor 52 and the capacitance C51 of the capacitor 51 have a size relationship of C52 >> C51.

  The first capacitor circuit 24 and the second capacitor circuit 25 are connected in series with each other, that is, the capacitor 51 and the capacitor 52 are connected in series with each other. Both ends of the series circuit of the first and second capacitor circuits 24 and 25 are connected to the input terminals T10 and T20. That is, one end of the series circuit is connected to the input terminal T10, and the other end of the series circuit is connected to the other input terminal T20.

The connection point between the capacitor 51 and the capacitor 52 is connected to the output terminal T30. The output terminal T40 is connected to the other end of the series circuit together with the input terminal T20.
As shown in FIG. 2, each of the adjusting capacitors 53a, 53b, and 53c constituting the adjusting circuit 60 is independent from the capacitor 52 via jumper terminals J1 to J3, or any two of them are connected. They are provided in combination or all in parallel. That is, in each of the adjustment capacitors 53a, 53b, and 53c, jumper terminals J1 to J3 are provided on the terminal on the output terminal T40 side. Jumper terminals J1 to J3 correspond to connection terminals.

  In the present embodiment, the jumper terminals J1 to J3 are a pair of terminals provided with jumper pins, and can be short-circuited by a jumper socket JS provided detachably with respect to the terminals. The jumper socket JS corresponds to connection means.

  The adjustment capacitors 53a, 53b, and 53c are capacitors for voltage correction, and have different capacitances, and the capacitances C53a, C53b, and C53c are smaller than the capacitance C52 of the capacitor 52. It has a capacitance.

That is,
C52 >> C53a, C53b, C53c
It is.

  When any one of the jumper terminals J1 to J3 is short-circuited by the jumper socket JS, one adjustment capacitor is used for voltage adjustment. Further, any two or all of the jumper terminals J1 to J3 are short-circuited by the jumper socket JS, thereby forming a composite capacitor for voltage adjustment. As described above, the adjustment circuit 60 includes the adjustment capacitors 53a, 53b, and 53c and the jumper terminals J1 to J3, and the adjustment capacitors 53a, 53b, and 53c can form a parallel circuit with respect to the capacitor 52. It is considered as a circuit.

  2 and 4, Cx connected in parallel to the capacitor 52 includes the capacitance of a lead wire (not shown) connecting the capacitor 52 and the adjustment capacitor 53 and the various capacitors. The electrostatic capacitance peculiar to electric power equipment including the electrostatic capacitance etc. of the circuit board (not shown) to be shown is shown.

The output terminals T30 and T40 of the voltage detection circuit 21 are connected to the signal processing unit 26, and the voltage V1 between the output terminals T30 and T40 is supplied to the signal processing unit 26.
This voltage V1 is obtained based on the following voltage division ratio of the capacitor 51, the capacitor 52, the adjustment capacitor 53, and the electrostatic capacitance Cx unique to the power device. The electrostatic capacitance Cx inherent to the power equipment is the electrostatic capacitance caused by the circuit board, output connector, cable (ie, lead wire), etc. on which the various capacitors (including the adjustment capacitor) and various electric circuits are mounted. Capacity.

Voltage division ratio = {C51 / (C51 + C52 + C53 + Cx)} (1)
That is, the voltage V1 is a voltage obtained based on the following formula (2).
V1 = {C51 / (C51 + C52 + C53 + Cx)} Vu (2)
C53 is the capacitance of the adjustment capacitor 53 (including the capacitance of the single adjustment capacitor or the capacitance of the composite capacitor). In the adjustment capacitor 53, when none of the jumper terminals J1 to J3 is short-circuited, the capacitance C53 is zero.

  Similarly, the V-phase and W-phase voltages Vv and Vw of the distribution line L are applied to the other voltage detection circuits 22 and 23, and the voltage V2 which is a value detected according to the voltage detection circuits 22 and 23 is applied. , V3 are supplied to the signal processing unit 26. The signal processing unit 26 outputs a voltage detection signal to the control unit 27 based on the voltages V1 to V3 from the voltage detection circuits 21 to 23. The signal processing unit 26 is configured by an analog circuit, a digital circuit, or the like. The control unit 27 controls opening / closing of the opening / closing unit 10a based on the voltage detection signal.

Now, the operation of the voltage measuring device 20 configured as described above will be described.
In the voltage measuring device 20 of the switch 10, there is a deviation in the voltage division ratio between the first capacitor circuit 24 and the second capacitor circuit 25 because of the capacitance Cx inherent to the power device. This shift in the voltage division ratio is a smaller value than the output voltage value when there is no capacitance Cx.

For this purpose, the deviation of the voltage dividing ratio is corrected, that is, adjusted using the adjusting capacitors 53a, 53b, and 53c.
Specifically, first, the capacitor 52 is determined to have a capacitance that takes into account the capacitance Cx unique to the power device, and a combination (adjustment capacitors 53a, 53b) that results in the capacitance of the considered capacitance Cx. , 53c connected) is calculated and determined in consideration of the change rate of the output voltage. In the determined combination, jumper terminals J1 to J3 provided on the adjustment capacitors 53a, 53b, and 53c are short-circuited by a jumper socket JS. And the output voltage of output terminal T30, T40 is detected in the state which applied the same voltage as a phase voltage between input terminal T10, T20. And this output voltage is compared with the reference voltage which should be obtained in the state to which the said phase voltage was applied previously.

  If this output voltage does not match the reference voltage, the jumper socket JS of the adjustment capacitors 53a, 53b, 53c is removed or attached, and any two adjustment capacitors or any one adjustment capacitor is installed. The capacitor 52 is connected in parallel. By changing the jumper socket JS, the deviation of the voltage dividing ratio is corrected, and finally, the output voltage is repeatedly corrected so that it matches the reference voltage or the output voltage is within the allowable accuracy range.

Therefore, there is a possibility that all the adjusting capacitors 53a, 53b, and 53c are connected, or that no adjusting capacitor is connected.
When such adjustment is performed, the connection of the adjustment capacitors is changed so that the capacitance of the adjustment capacitors can be sequentially reduced by combining the adjustment capacitors or using the adjustment capacitors. An example of this is described in the examples below.

(Example)
In this embodiment, the values of the adjustment capacitors 53a, 53b, and 53c are 680 pF, 330 pF, and 180 pF, respectively, and the capacitance Cx specific to the power device is 250 pF. The capacitance of the capacitor 51 is 50 pF, the capacitance of the capacitor 52 is 49500 pF, and the applied voltage between the input terminals T10 and T20 is 3810V. The capacitance Cx is an assumed value and varies somewhat depending on the device.

  Table 1 shows that the output voltage between T30 and T40 when the adjusting capacitors 53a, 53b, and 53c are not used alone, in combination with any two, or when all are used is divided from the above equation (2). The pressure ratio is calculated, and the output value change rate is calculated based on the calculated value.

  Here, the change rate of the output value based on the center value is determined based on the output voltage when the parallel circuit combining the adjustment capacitors 53b and 53c is connected in parallel to the capacitor 52, with the output voltage as a reference and other values. This is a calculation of the output value change rate of the output voltage.

又、初期状態基準の出力値変化率は、調整コンデンサ５３ａ，５３ｂ，５３ｃを全て組み合わせた並列回路をコンデンサ５２に対して並列接続した場合の出力電圧を基準として、他の出力電圧の出力値変化率を算出したものである。

The output value change rate based on the initial state is the change in the output value of other output voltages with reference to the output voltage when a parallel circuit in which all the adjusting capacitors 53a, 53b, and 53c are connected in parallel to the capacitor 52. The rate is calculated.

  Table 1 shows the capacitance obtained by using the adjusting capacitors alone or in combination in order from the left to the largest. When the capacitance decreases in order, the output value change rate is 0.29 to It turns out that it becomes large in the range of 0.36%. That is, the adjustment capacitor of this embodiment can be divided even if the voltage dividing ratio of the capacitors 51 and 52 is shifted due to variations in the capacitance Cx inherent to the power device by changing the combination of the adjustment capacitors. The pressure ratio can be corrected.

  Moreover, when the capacitances obtained by using the adjusting capacitors alone or in combination are arranged in descending order as in this embodiment, the output value change rate is in the range of 0.29 to 0.36% in order. Since the voltage is increased, the output voltage can be finely adjusted by changing the connection of each adjustment capacitor.

  In general, the capacitance Cx inherent to the power device is not large, but it has a large influence on the output voltage, so it is preferable to eliminate the deviation of the voltage division ratio. In addition, the allowable accuracy is preferably small. In this embodiment, the allowable accuracy at room temperature is within ± 0.25%.

Now, according to the present embodiment, the following effects can be obtained.
(1) The voltage measurement apparatus 20 of the present embodiment includes the adjustment circuit 60 including a plurality of adjustment capacitors 53a, 53b, and 53c for voltage correction. The adjustment circuit 60 is a jumper terminal that can be connected in parallel with the second capacitor circuit 25 by a composite capacitor formed by one or a combination of two or more of the plurality of adjustment capacitors 53a, 53b, and 53c. J1 to J3 are provided, and a jumper socket JS for connecting the terminals J1 to J3 is provided.

  As a result, one of the adjustment capacitors is temporarily connected in parallel using the jumper socket JS, the output voltage of the capacitor circuit for measuring the phase voltage is measured and compared with the reference voltage, and does not match the reference voltage. If so, you can change that connection. Then, the terminals J1 to J3 that are at the reference voltage are fully connected by the jumper socket JS. This makes it possible to accurately measure the phase voltage connected to the power device.

  (2) Moreover, in this embodiment, since the adjustment capacitor | condenser is provided with two or more so that adjustment capacitor | condenser 53a, 53b, 53c can comprise a parallel circuit, the switch 10 can mass-produce the same thing.

  (3) Further, in the present embodiment, adjustment of the capacitor 52 constituting the second capacitor circuit 25 which is a low voltage side capacitor circuit for voltage measurement is also performed by simply changing one or more jumper sockets JS to J1 to J3. Just set it up.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG.
Since the configuration of the adjustment circuit 60 of the voltage measuring device 20 of the second embodiment is different and the other configurations are the same, the same configurations as those of the first embodiment are denoted by the same reference numerals and redundant description is given. Omitted.

  Specifically, the adjustment circuit 60 is provided such that, in addition to the adjustment capacitors 53a, 53b, and 53c, a temperature compensation capacitor 53d can be connected in parallel to the capacitor 52 via the jumper terminal J4 as the adjustment capacitor. It has been. The jumper terminal J4 corresponds to a connection terminal.

In this case, the temperature compensation capacitor 53d is connected according to the environmental temperature used by the power device.
The temperature compensation capacitor 53d is provided to suppress the change by connecting the temperature compensation capacitor 53d in parallel even if there is a temperature change with respect to the capacitance of the capacitor 52 and the adjustment capacitors 53a, 53b, and 53c. It is a thing. Therefore, a capacitor having a temperature coefficient opposite to that of the capacitor 52 and the adjusting capacitors 53a, 53b, and 53c is used as the temperature compensating capacitor 53d. In the present embodiment, the temperature compensating capacitor 53d is configured by a polyester film capacitor. The temperature compensating capacitor 53d is connected in parallel to the capacitor 52 by connecting a jumper socket JS to the terminal J4.

In the second embodiment, the capacitor 51 is a ceramic capacitor of NP0 (= temperature coefficient 0 ppm / ° C.).
Now, according to the present embodiment, the following effects can be obtained.

  (1) The voltage measuring apparatus 20 of the present embodiment includes a temperature compensation capacitor as an adjustment capacitor. As a result, when a temperature compensation capacitor is used, the temperature change rate of the voltage division ratio can be reduced (the temperature change rate can be suppressed), which enables accurate measurement of the phase voltage connected to the power equipment. it can.

That is, for example, when the capacitor 52 and the adjusting capacitors 53a, 53b, and 53c have a temperature coefficient that becomes smaller due to a change (increase) in the ambient temperature, the capacity of the temperature compensation capacitor 53d having the opposite temperature coefficient is Because it grows
Partial pressure ratio = {C51 / (C51 + C52 + C53 + Cx)}
The rate of temperature change can be suppressed.

C53 includes the capacity of the temperature compensation capacitor 53d.
Further, when the capacitor 52 and the adjusting capacitors 53a, 53b, and 53c have a temperature coefficient that increases their capacity due to the change (increase) in the ambient temperature, the capacity of the temperature compensating capacitor 53d having the opposite temperature coefficient is small. Therefore, the temperature change rate of the partial pressure ratio can be suppressed.

(2) In the present embodiment, the temperature compensation capacitor 53d is constituted by a polyester film capacitor. As a result, the effect (1) of the present embodiment can be easily realized.
In addition, you may implement the said embodiment as follows.

  In the above embodiment, the capacitor 52 is composed of a ceramic capacitor, but a polystyrene film capacitor or a polypropylene film capacitor may be used.

  In the above embodiment, the jumper terminals J1 to J3 are jumper pins, but in addition to this configuration, metal terminals such as pads and eyelets may be used. In this case, instead of the jumper socket, a short-circuit member such as a jumper wire or a metal plate may be used. In this case, the connection means is constituted by the metal terminal and the short-circuit member.

In the above embodiment, as the connection means, the jumper terminals J1 to J3 are configured by jumper pins and jumper sockets, but may be configured as follows.
When assembling the voltage measuring device, all the jumper terminals J1 to J3 are short-circuited in advance with jumper wires, that is, temporarily connected, and before the factory shipment, the reference voltage is connected between the input terminals T10 and T20. In the applied state, the output voltage between T30 and T40 is measured. In this state, if the output voltage is not the reference voltage, the jumper wire connected in accordance with a predetermined procedure is disconnected, and the output voltage matches the reference voltage, or the output voltage is set to an allowable accuracy. Be within the range. In this case, the terminal where the jumper line is not cut is short-circuited by the jumper line to make the main connection.

As a connection means, a dip switch that can be switched on and off may be used instead of the jumper terminal and the jumper socket.
In the above embodiment, on the customer side of the distribution line L provided with the switch 10, only one is provided so as to measure the voltage of the distribution line L of each phase, but the number is not limited to one. Absent. In the switch, one voltage measuring device 20 may be further provided so that the voltage of each phase of the distribution line L on the substation side can be measured.

In the voltage measuring device 20, the number of the voltage detection circuits 21 to 23 is not limited to three, and may be one or two, for example.
In the above embodiment, a switch is used as the power device. However, the power measuring device provided on the distribution line includes a transformer, a circuit breaker, and a disconnector, and may be provided in these devices.

In the embodiment, the plurality of adjustment capacitors 53a, 53b, and 53c have different capacitances, but may have the same capacitance.
In the second embodiment, the terminal J4 is provided as a connection terminal so that the temperature compensation capacitor 53d can be connected in parallel to the capacitor 52. However, as shown in FIG. 52 may be connected in parallel. In this case, as the temperature compensation capacitor 65, a capacitor having a temperature coefficient opposite to that of the capacitor 52 and the adjustment capacitors 53a, 53b, and 53c is used. In the present embodiment, the second capacitor circuit 25 includes a parallel circuit of a capacitor 52 and a temperature compensation capacitor 65.

  In each of the above embodiments, the first capacitor circuit 24 is composed of a single capacitor 51, but is not limited to a single capacitor, and may be composed of a series circuit of two or more capacitors, or two You may comprise by the parallel circuit of the above several capacitor | condenser.

In each of the above embodiments, the second capacitor circuit 25 is composed of a single capacitor 52. However, the second capacitor circuit 25 is not limited to a single capacitor, and may be composed of a series circuit of two or more capacitors, or two or more. A parallel circuit of a plurality of capacitors may be used.
The output voltage can be finely adjusted by making the values of the adjustment capacitors 53a, 53b, and 53c smaller than those of the above embodiments, such as 100 pF, 200 pF, and 390 pF.
O The adjustment range can be further expanded by increasing the number of adjustment capacitors 53a, 53b, and 53c.
In each of the embodiments described above, one connection terminal is provided for each of the adjustment capacitors 53a, 53b, and 53c. For example, as shown in the example of FIG. 7, the adjustment capacitor is connected between the power supply side, the ground side, and each adjustment capacitor connection. By providing the connection terminal J to which the jumper socket JS can be connected, 13 adjustment circuits 60 having different electrostatic capacities can be obtained. Further, as shown in the example of FIG. 8, 17 adjustment circuits 60 having different capacitances can be obtained by connecting connection of the adjustment capacitors in a complicated manner and providing a connection terminal J to which the jumper socket JS can be connected. Can do.
In each of the above embodiments, the combination of the adjusting capacitors 53a, 53b, and 53c and the rate of change of the output voltage are calculated in consideration of the assumed capacitance Cx, and the combination is determined. The jumper terminals between the determined combinations are short-circuited, and the same voltage as the phase voltage is applied between the input terminals T10 and T20 to detect the output voltages of the output terminals T30 and T40. The output voltage is adjusted to match the reference voltage or the output voltage is within the allowable accuracy range by changing the jumper terminal in comparison with the reference voltage. It may be configured.

  First, the same voltage as the phase voltage is applied between the input terminals T10 and T20, and the output voltages of the output terminals T30 and T40 are detected. The output voltage and the reference voltage are compared to calculate a deviation, and the combination of the adjustment capacitors 53a, 53b, and 53c is determined. The terminals between the determined combinations may be short-circuited, and the output voltage may be adjusted to match the reference voltage by changing the terminals while checking the output voltage, or the output voltage may be adjusted to be within the allowable accuracy range.

  First, all the jumper terminals provided in all the adjusting capacitors 53a, 53b, and 53c are short-circuited, and the same voltage as the phase voltage is applied between the input terminals T10 and T20, so that the output terminals T30 and T40 are connected. Detect the output voltage. Then, by comparing the output voltage with the reference voltage, the output voltage may be matched with the reference voltage by changing the terminal, or the output voltage may be adjusted to be within the allowable accuracy range.

Next, the technical idea that can be grasped from the above-described embodiment in addition to the claims will be described below.
(1) In a voltage measurement method for a power device in which a pair of capacitor circuits (C1, C2) are connected in series and the voltage of each phase can be measured by voltage division, adjustment for voltage compensation is performed in parallel with one capacitor circuit. A method for measuring a voltage of a power device, wherein a capacitor is temporarily connected and one or more adjustment capacitors of the adjustment capacitors can be fully connected so as to match a reference voltage during voltage compensation adjustment. In this way, when using a temperature compensation capacitor, the temperature change rate of the voltage division ratio can be reduced (the temperature change rate can be suppressed), thereby measuring the phase voltage connected to the power equipment. Can be measured accurately.

Explanatory drawing of the series circuit of the conventional capacitor circuit. Explanatory drawing of the series circuit of the capacitor circuit of embodiment. The block diagram which shows the outline of the switch. FIG. 2 is a block diagram showing an outline of a voltage measuring device 20. Explanatory drawing of the adjustment circuit 60 of other embodiment. Explanatory drawing of the adjustment circuit 60 of other embodiment. Explanatory drawing of the adjustment circuit 60 of other embodiment. Explanatory drawing of the adjustment circuit 60 of other embodiment.

Explanation of symbols

24 ... 1st capacitor circuit (capacitor circuit),
25 ... second capacitor circuit (capacitor circuit), 60 ... adjustment circuit,
J1 to J3 ... Terminal (connection terminal), S ... Jumper socket (connection means)

Claims (5)

In a voltage measuring device for a power device in which a pair of capacitor circuits are connected in series and the phase voltage can be measured by the divided output of one capacitor circuit,
It has an adjustment circuit that includes multiple adjustment capacitors for voltage compensation,
The adjustment circuit includes a connection capacitor that is connected to the one capacitor circuit in parallel, and a connection unit that connects between the connection terminals, and a synthetic capacitor including a combination of the plurality of adjustment capacitors. A voltage measuring device for power equipment.   2. The voltage measuring apparatus for a power device according to claim 1, wherein the adjustment capacitor includes a temperature compensation capacitor.   The voltage measuring device for a power device according to claim 2, wherein the temperature compensation capacitor is a polyester film capacitor.   The voltage measuring apparatus for a power device according to claim 1, wherein the adjustment capacitor is a ceramic capacitor.   The voltage measuring device for a power device according to any one of claims 1 to 4, wherein the connecting means is a jumper socket capable of jumper connection.

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