JP2007292483A - Instrument transformer for two-way metering and two-way electric power metering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instrument transformer for two-way metering and a two-way electric power metering system for solving a problem that large installation space is taken up for a CT and a VT in terms of safety and withstand voltage when they are used for high tension or extra high tension. <P>SOLUTION: This instrument transformer 100 for two-way metering used to two-way meter electric energy/reactive energy as to three-phase transmission wires, is equipped with first and second instrument current transformation parts 10 and 20 connected to a first-phase transmission wire of the three-phase transmission wires, third and fourth instrument current transformation parts 30 and 40 connected to a second-phase transmission wire of the three-phase transmission wires, and an interphase voltage transformation means 50 transforming an interphase voltage between the third-phase and first-phase transmission wires of the three-phase transmission wires so that it can be measured between the first and second instrument current transformation parts on electric circuits while transforming an interphase voltage between the third-phase and second-phase transmission wires so that it can be measured between the third and fourth instrument current transformation parts on the electric circuits. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transformer for bidirectional metering and a bidirectional power metering system, and more particularly to one used for a high-voltage bidirectional power system having a high voltage exceeding 600 V and a high voltage of 7 KV or less and exceeding 7 KV.

  In recent years, electric power sales for business establishments have been liberalized, and a demand form in which electric power consumers having private power generation facilities among electric power consumers sell surplus power to electric power companies has begun to be implemented. In such a case, it is necessary to measure the amount of electric power, the amount of reactive power, etc. in the bidirectional power flow for receiving and transmitting power. Conventionally, in such a case, a measurement circuit is configured by two instrument current transformers (CT) and two instrument transformers (VT) as shown in FIG. When measuring the electric energy, reactive electric energy, etc., two sets of measuring circuits as shown in FIG.

As a conventional related technique, a bidirectional power metering apparatus that measures active power and reactive power in the forward direction and the reverse direction by pulses has been proposed (see Reference 1).
Japanese Patent No. 3544466

  However, when used at a high voltage or extra high voltage, it is necessary to make the installation space for CT and VT larger from the viewpoint of withstand voltage for safety. Therefore, as described above, there are problems such that the two sets of these devices cannot be accommodated in a cubicle prepared on the premise of the conventional one direction, and further sites are required for facilities.

  In addition, there are often cases where the difference between the amount of power generated by the customer and the amount of power received is large. When the amount of power generated by the customer is small, it is sometimes difficult to select a low-power measuring instrument and CT or VT. Furthermore, since the VT is on the CT load side on the reverse power flow side, there is a problem that the power loss of the VT is theoretically measured.

  It is an object of the present invention to provide a bidirectional metering transformer and a bidirectional power metering system that solve these problems.

  The present inventors have found that it is appropriate to place VT in the middle of CT on an electric circuit, and have completed the following present invention.

  (1) A bidirectional measuring instrument transformer used for measuring bidirectional electric energy and reactive electric energy in a three-phase transmission line, and connected to the first-phase transmission line of the three-phase transmission line A first instrument current transformer and a second instrument current transformer, and a third instrument current transformer and a fourth instrument transformer connected to the second phase transmission line of the three-phase transmission line. The interphase voltage between the flow section and the third-phase transmission line of the three-phase transmission line and the first-phase transmission line is converted into the first instrument current transformer section and the second instrument transformer section on the electric circuit. The voltage between the third phase power transmission line and the second phase power transmission line is converted into a voltage that can be measured between the third current transmission section and the third current transmission section on the electric circuit. A bidirectional measuring instrument transformer comprising: an inter-phase voltage transforming means for transforming so as to be measured between the four instrument current transformers.

  The transformer for bidirectional measuring instrument of the invention of (1) is connected to the first phase transmission line of the three-phase transmission line on the electric circuit, and is used for the first instrument current transformer and the second instrument. A current transformer is provided. A third instrument current transformer and a fourth instrument current transformer are provided on the electric circuit connected to the second-phase power transmission line.

  Furthermore, the bidirectional measuring instrument transformer according to the invention of (1) is configured such that the interphase voltage between the third-phase transmission line and the first-phase transmission line of the three-phase transmission line is expressed as the first on the electric circuit. The voltage is transformed so that it can be measured between the second current transformer and the second current transformer, and the interphase voltage between the third phase power line and the second phase power line is An interphase voltage transforming means for transforming the circuit so as to be measured between the third instrument current transformer and the fourth instrument current transformer is provided.

  By connecting such a bidirectional measuring instrument transformer of the invention of (1) to a three-phase power transmission line, compared to the case where two sets of interphase voltage transformers are required as in the prior art, 1 You can do it as a set. Therefore, installation space and cost can be saved. Further, the interphase voltage transformation means is provided between the third phase and the first instrument current transformer and the second instrument current transformer on the third phase and the electric circuit, and between the third instrument current transformer and the fourth instrument. Since it is arranged to measure the voltage between the current transformer and the VT is on the CT load side on the reverse power flow side, the problem of theoretically measuring the power loss of the VT can also be solved. .

  Note that the third instrument current transformer is arranged in a direction opposite to the traveling direction of power to be measured on the electric circuit from the first instrument current transformer. Further, it is desirable that the fourth instrument current transformer is arranged in a direction opposite to the traveling direction of the electric power to be measured on the electric circuit from the second instrument current transformer.

  (2) The bidirectional measuring instrument transformer according to (1), wherein the first instrument current transformer, the second instrument current transformer, and the third instrument current transformer. And the fourth instrument current transformer has a settling means for individually setting in accordance with a measured current to be measured.

  According to the invention of (2), the magnitude of the power to be measured when measuring the bidirectional power is often greatly different. Electricity providers regularly calibrate the meter for electric energy, and calibrate the transformation ratio of the transformer and the multiplication factor of the meter. Normally, when the width of the power to be measured is increased, the range in which the transformer is linear is limited, so that the error increases and it is difficult to measure an accurate value. According to the invention of (2), it is possible to select a metamorphic section having an appropriate metamorphosis ratio with an individual instrument depending on the direction of power flow. Therefore, measurement errors can be reduced in both directions.

  (3) A bidirectional power metering system for bidirectional power and reactive power in a three-phase transmission line, wherein the first current transformer is connected to the first-phase transmission line of the three-phase transmission line And the second instrument current transformer, the third instrument current transformer and the fourth instrument current transformer connected to the second phase power transmission line of the three-phase power transmission line, and the three-phase power transformer An interphase voltage between the third-phase power transmission line and the first-phase power transmission line is transmitted between the first instrument current transformer and the second instrument current transformer on the electric circuit. Transform so that it can be measured, and the interphase voltage between the third-phase power transmission line and the second-phase power transmission line is converted into the third instrument current transformer and the fourth instrument current transformer on the electric circuit. A bidirectional power metering system, comprising:

  The invention of (3) is an invention of a bidirectional power metering system. (1) The invention includes a separate measuring instrument current transformer having the same function as the bidirectional measuring instrument transformer and an interphase voltage transforming means. By arranging and connecting in the same manner on the circuit, the same effect as the invention of (1) can be obtained. In addition, since the current transformer part for an instrument comprises an individual system, it can be replaced with the current transformer for an instrument.

  (4) A bidirectional measuring instrument transformer used for measuring bidirectional electric energy and reactive electric energy in a three-phase four-wire transmission line, wherein the first phase of the three-phase four-wire transmission line A first instrument current transformer and a second instrument current transformer connected to the transmission line, and a third instrument transformer connected to the second phase power transmission line of the three-phase four-wire transmission line. And a fifth instrument current transformer and a sixth instrument current transformer connected to the third phase power transmission line of the three-phase four-wire transmission line. Between the neutral line of the three-phase four-wire transmission line and the first-phase transmission line between the first instrument current transformer and the second instrument current transformer on the electric circuit. And the voltage between the neutral wire and the second phase power transmission line between the third instrument current transformer and the fourth instrument current transformer on the electrical circuit, and 5th instrument on neutral wire and electrical circuit Voltage measuring means for transforming the voltage between the third phase transmission line between the current transformer and the sixth instrument current transformer so as to measure the bidirectional metering instrument Transformer.

  The invention of (4) relates to a transmission line of a three-phase four-wire transmission line. The three-phase four-wire power transmission method is suitable for supplying to regions and customers where medium-capacity single-phase and three-phase loads are mixed. Since there is a neutral line and it is necessary to measure the electric energy and reactive electric energy for a single phase, the configuration is as described above, but the effect is the same as in the invention of (1).

  (5) A bidirectional power metering system used for metering bidirectional power and reactive energy in a three-phase four-wire transmission line, wherein the first-phase transmission line of the three-phase four-wire transmission line A first instrument current transformer and a second instrument current transformer connected, a third instrument current transformer connected to the second phase power transmission line of the three-phase four-wire transmission line; and A fourth instrument current transformer, a fifth instrument current transformer and a sixth instrument current transformer connected to the third phase transmission line of the three-phase four-wire transmission line, and the 3 A voltage between a neutral line of a phase 4-wire transmission line and the first phase transmission line between the first instrument current transformer and the second instrument current transformer on the electric circuit; A voltage between the neutral wire and the second phase power transmission line between the third instrument current transformer and the fourth instrument current transformer on the electrical circuit, and the neutral wire. And for the fifth instrument on the electrical circuit A bi-directional power metering system comprising voltage transforming means for transforming the voltage between the flow section and the third phase power transmission line between the sixth instrument current transformer section so that the voltage can be measured .

  The invention of (5) is an invention of a bidirectional power metering system for a three-phase four-wire transmission line. The same effect as the invention of (4) can be obtained. As in the case of the invention of (3), the current transformer for the instrument can be replaced with a current transformer for the instrument.

  According to the present invention, it is possible to save installation space as well as cost. When measuring bidirectional power consumption, VT is on the CT power supply side in both directions, so that the VT power loss is measured. The problem can be solved.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. This is merely an example, and the technical scope of the present invention is not limited to this.

[First embodiment]
FIG. 1 is a block diagram of a bidirectional measuring instrument transformer according to the present invention and an example of connection to a three-phase transmission line. FIG. 2 is a diagram illustrating the principle of the current transformer for the instrument. FIG. 3 is a diagram showing the principle of the instrument transformer. FIG. 4 is a diagram illustrating the principle of a capacitor-type instrument transformer. Hereinafter, description will be made with reference to these drawings.

  As shown in FIG. 1, the bidirectional measuring instrument transformer 100 of the present invention is a first instrument current transformer connected to a first-phase transmission line (a U-phase in FIG. 1) of a three-phase transmission line. Unit 10 and second instrument current transformer 20 and third instrument current transformer 30 and fourth instrument connected to the second phase power transmission line (V phase in FIG. 1) of the three-phase power transmission line The interphase voltage of the current transformer 40, the third-phase transmission line of the three-phase transmission line (W-phase in FIG. 1), and the first-phase transmission line or the second-phase transmission line can be measured. And an interphase voltage transforming means 50 for transforming.

  As shown in FIG. 1, each of these current transformers and interphase voltage transforming means 50 is used to measure power 1 and reactive power of meter 1 (70) that measures power and reactive power of power 1. It is connected to the measuring instrument 2 (80).

  FIG. 2 is a diagram showing the principle of the current transformers 10, 20, 30, 40 for instruments. The electricity consumption of high voltage and large current loads cannot be directly measured with an electric meter. For this purpose, the current transformer for an instrument is used together with an electric instrument, and serves to accurately reduce a large current to a level that can be handled by the electric instrument. The current transformer for an instrument includes an iron core 15 having a primary winding 12 having a small number of turns through which a large load current flows and a secondary winding 14 having a large number of turns capable of obtaining a current converted as small as can be measured by an electric meter. It is a structure wound around. The current transformer for the instrument accurately transforms the load current to a fraction of the current transformation ratio.

  A value obtained by dividing the number of turns of the secondary winding by the number of turns of the primary winding is called a turns ratio. In an ideal instrument current transformer, the current ratio is almost the same as the turns ratio. However, in an actual current transformer for an instrument, an error occurs because the winding impedance, the excitation current, and the burden on the secondary side (current circuit of the connecting conductor and the electric instrument) cannot be ignored.

  As shown in FIG. 1, the primary winding 12 of the first instrument current transformer 10 is connected to the first-phase transmission line (the U-phase in FIG. 1) of the three-phase transmission line, and the secondary winding 14. Is connected to the current measurement terminal of the meter 1 (70). Similarly, the primary winding 22 of the second instrument current transformer 20 is connected to the first-phase transmission line (the U-phase in FIG. 1) of the three-phase transmission line, and the secondary winding 24 is connected to the instrument 2 ( 80) current measurement terminal. The primary winding 32 of the third instrument current transformer 30 is connected to the second-phase transmission line of the three-phase transmission line (W-phase in FIG. 1), and the secondary winding 34 is connected to the instrument 1 (70 ) Is connected to the current measurement terminal. Further, the primary winding 42 of the fourth instrument current transformer 40 is connected to the second phase transmission line (W phase in FIG. 1) of the three-phase transmission line, and the secondary winding 44 is connected to the instrument 2 (80 ) Is connected to the current measurement terminal.

  FIG. 3 is a diagram showing the principle of an electromagnetic instrument transformer. High voltage exceeding 600V and below 7KV, and special high voltage exceeding 7KV cannot be measured directly with an electric meter. For this reason, the instrument transformer is used together with an electric meter to accurately lower the high voltage and extra high voltage to a level that can be handled by the electric meter. In the embodiment of the present invention shown in FIG. 1, the interphase voltage transforming means 50 is depicted as an electromagnetic type.

  The interphase voltage transformer 50 includes an instrument transformer 51 and an instrument transformer 55. The electromagnetic-type instrument transformer 51 includes a primary winding 52 for applying a load voltage (primary voltage) and a secondary winding 53 having a small number of turns that can obtain a voltage converted to be small enough to be measured by an electric meter. 54. The instrument transformer transforms the load voltage accurately to a ratio of the transformation ratio.

  A value obtained by dividing the number of turns of the secondary winding by the number of turns of the primary winding is called a turns ratio. In an ideal instrument transformer, the transformation ratio is almost the same as the inverse of the turns ratio. However, in an actual instrument transformer, an error occurs because the winding impedance, the excitation current, and the burden on the secondary side (current circuit of the connecting conductor and the electric instrument) cannot be ignored.

  As shown in FIG. 1, as described above, the interphase voltage transforming means 50 includes the instrument transformer 51 and the instrument transformer 55, and the primary winding 52 of the instrument transformer 51 is a third-phase transmission line ( 1 is connected between the V-phase) and the first-phase power transmission line (U-phase in FIG. 1). The secondary winding 53 of the instrument transformer 51 is connected to the voltage measurement terminals of the instrument 1 (60) and the instrument 2 (70) as shown.

  The primary winding 56 of the instrument transformer 55 is connected between a third phase transmission line (V phase in FIG. 1) and a second phase transmission line (W phase in FIG. 1). The secondary winding 58 of the instrument transformer 51 is connected to the voltage measurement terminals of the instrument 1 (60) and the instrument 2 (70) as shown. As shown in FIG. 1, the interphase voltage transforming means 50 is disposed between the first instrument current transformer 10 and the second instrument current transformer 20.

  By using the bidirectional measuring instrument transformer 100 connected as described above, this corresponds to the setting of two wattmeters in accordance with the flow of electric power (see Electrical Engineering Handbook, New Edition P310). 1), the power in the direction of tidal current 1 shown in FIG. 1 can be measured by meter 1 (60), and the power in the direction of tidal current 2 can be measured by meter 2 (70).

  By using the bidirectional measuring instrument transformer 100 having such a configuration, the number of measuring transformers can be reduced by one set compared to the conventional one. In this connection, particularly in the case of an extra high voltage, it is possible to save an insulator for special insulation or the like for connection to the extra high voltage. Therefore, cost and installation space can be saved. Further, since the interphase voltage transforming means 50 is disposed in the middle of the current transformer for the meter, the interphase voltage transforming means 50 is disposed upstream of the current transformer for measuring the current with respect to the flow of power to be measured. It is in. Therefore, in both directions, the measurement can be performed without including the loss generated in the interphase voltage transformer 50.

  FIG. 4 is a diagram illustrating the principle of a capacitor-type instrument transformer. As shown in FIG. 4, the capacitor-type instrument transformer has a structure in which two capacitors having capacitances C1 and C2 are connected in series using the action of a capacitance divider. The capacitor-type instrument transformer can accurately transform the load voltage to one voltage ratio by using the capacitance of the capacitor.

  The interphase voltage transforming means 50 may be a capacitor-type instrument transformer, instead of the electromagnetic instrument transformer described above.

  Further, as shown in FIG. 1, the current transformer for the instrument is provided in accordance with the flow direction of the tidal current, so that the instrument and the current transformation ratio can be set in accordance with the actually flowing current. That is, it has a settling means adapted to the current. In particular, as described above, in an actual instrument current transformer, the winding impedance, the excitation current, and the burden on the secondary side (current circuit of the connecting conductor and the electric instrument) cannot be ignored, and errors occur, so there are few errors. Setting up is meaningful.

[Second Embodiment]
The second embodiment relates to the bidirectional power metering system of the present invention. Whereas the bidirectional measuring instrument transformer 100 described in the first embodiment is integrally configured, individual instrument current transformers and instrument transformer parts are separately prepared and shown in FIG. By performing the same connection as shown in 1, the same effect can be realized.

  In this case, since the current transformer part for an instrument and the transformer part for an instrument are prepared separately, it may be a current transformer for an instrument and a transformer for an instrument. In this case, the same effect can be expected.

[Third embodiment]
The third embodiment relates to a bidirectional measuring instrument transformer used for a transmission line of a three-phase four-wire transmission line. The three-phase four-wire power transmission method is suitable for supplying to regions and customers where medium-capacity single-phase and three-phase loads are mixed. Since there is a neutral wire and it is necessary to measure the amount of electric power and reactive power for a single phase, the above configuration is obtained.

  FIG. 5 is a block diagram of a bidirectional measuring instrument transformer for a three-phase four-wire transmission line according to the present invention and an example of connection to the three-phase four-wire transmission line. As shown in FIG. 5, the three-phase four-wire transmission line bidirectional measuring instrument transformer 200 is connected to the first-phase transmission line (U phase in FIG. 5) of the three-phase four-wire transmission line. The first instrument current transformer 210 and the second instrument current transformer 220 are connected to the second phase power transmission line (phase V in FIG. 5) of the three-phase four-wire transmission line. The fifth current transformer 230 connected to the third current transmission line (W phase in FIG. 5) of the current transformer 230 and the fourth current transformer 240 and the three-phase four-wire transmission line. 6 instrument current transformers including a part 250 and a sixth instrument current transformer 260.

  Further, the neutral phase (N in FIG. 5) of the three-phase four-wire transmission line and the first phase between the first instrument current transformer 210 and the second instrument current transformer 220 on the electric circuit. The voltage between the transmission line (the U phase in FIG. 5), the neutral line (N in FIG. 5), and the third instrument current transformer 230 and the fourth instrument current transformer 240 on the electric circuit. Between the second phase power transmission line (phase V in FIG. 5), the neutral line (N in FIG. 5), the fifth instrument current transformer 250 and the sixth instrument on the electric circuit Voltage transformation means 270 is provided for transforming the voltage between the third phase power transmission line (the W phase in FIG. 5) between the current transformation section (260) and the voltage transformation means so as to be measured.

  In this way, there are many elements compared to the case of three phases. In the case of a three-phase four-wire transmission line, the load includes those used in a single phase. This is because it is necessary to measure the voltage and current.

  However, in the case of a three-phase four-wire transmission line, the conventional method requires one more set corresponding to the voltage transformation means 270 of FIG. Therefore, by connecting as shown in FIG. 5, the same effects as described in the first embodiment can be obtained.

[Fourth embodiment]
The fourth embodiment relates to a bidirectional power metering system used for a transmission line of a three-phase four-wire transmission line.
Whereas the two-way measuring instrument transformer 200 used in the transmission line of the three-phase four-wire transmission line described in the third embodiment is configured integrally, each current transformer part for an instrument The same operation and effect can be realized by separately preparing the instrument transformer and connecting it in the same manner as shown in FIG.

  In this case, since the current transformer part for an instrument and the transformer part for an instrument are prepared separately, it may be a current transformer for an instrument and a transformer for an instrument. In this case, the same effect can be expected.

  As mentioned above, although demonstrated using embodiment of this invention, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention. For example, as described above, the instrument current transformer and the instrument transformer can be realized in the same manner by using an instrument current transformer and an instrument transformer having the same performance.

It is a figure which shows the example connected to the block diagram of the bidirectional | two-way measuring instrument transformer of this invention, and a three-phase power transmission line. It is a figure which shows the principle of the electromagnetic type current transformation part for instruments. It is a figure which shows the principle of the electromagnetic type transformer part for instruments. It is a figure which shows the principle of the capacitor | condenser type instrument transformer part. It is a figure which shows the example connected to the block diagram of the bidirectional | two-way measuring instrument transformer for three-phase four-wire type transmission lines of this invention, and a three-phase four-wire type transmission line. It is a figure which shows the measuring methods, such as the conventional electric energy and reactive electric energy.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st instrument current transformation part 20 2nd instrument current transformation part 30 3rd instrument current transformation part 40 4th instrument current transformation part 50 Interphase voltage transformation means 100 Bidirectional measuring instrument transformer 200 Two-way measuring instrument transformer for three-phase four-wire transmission line 210 First instrument current transformer 220 Second instrument current transformer 230 Third instrument current transformer 240 Fourth instrument Current Transformer 250 Fifth Instrument Current Transformer 260 Sixth Instrument Current Transformer 270 Voltage Transformer

Claims (5)

A bidirectional measuring instrument transformer used for measuring bidirectional and reactive energy in a three-phase transmission line,
A first instrument current transformer and a second instrument current transformer connected to the first phase power transmission line of the three-phase power transmission line;
A third instrument current transformer and a fourth instrument current transformer connected to the second phase power transmission line of the three-phase power transmission line;
The interphase voltage between the third-phase transmission line and the first-phase transmission line of the three-phase transmission line is determined by the electric circuit between the first instrument current transformer and the second instrument current transformer. The voltage is transformed so that it can be measured in between, and the interphase voltage between the third-phase power transmission line and the second-phase power transmission line is measured on the electric circuit for the third instrument current transformer and the fourth instrument. An interphase voltage transforming means for transforming so as to be able to measure between the current transformer and
Transformer for two-way measuring instrument equipped with. The bidirectional measuring instrument transformer according to claim 1,
The first instrument current transformer, the second instrument current transformer, the third instrument current transformer, and the fourth instrument current transformer are individually adapted to the measurement current to be measured. A bidirectional measuring instrument transformer characterized by comprising settling means for setting. A bi-directional power metering system for bidirectional and reactive power in a three-phase transmission line,
A first instrument current transformer and a second instrument current transformer connected to the first phase power transmission line of the three-phase power transmission line;
A third instrument current transformer and a fourth instrument current transformer connected to the second phase power transmission line of the three-phase power transmission line;
The interphase voltage between the third-phase transmission line and the first-phase transmission line of the three-phase transmission line is determined by the electric circuit between the first instrument current transformer and the second instrument current transformer. The voltage is transformed so that it can be measured in between, and the interphase voltage between the third-phase power transmission line and the second-phase power transmission line is measured on the electric circuit for the third instrument current transformer and the fourth instrument. An interphase voltage transforming means for transforming so as to be able to measure between the current transformer and
Two-way power metering system with A bidirectional measuring instrument transformer used for measuring bidirectional power and reactive power in a three-phase four-wire transmission line,
A first instrument current transformer and a second instrument current transformer connected to the first phase power transmission line of the three-phase four-wire power transmission line;
A third instrument current transformer and a fourth instrument current transformer connected to the second phase power transmission line of the three-phase four-wire power transmission line;
A fifth instrument current transformer and a sixth instrument current transformer connected to the third phase power transmission line of the three-phase four-wire power transmission line;
Between the neutral line of the three-phase four-wire transmission line and the first-phase transmission line between the first instrument current transformer and the second instrument current transformer on the electric circuit. A voltage, a voltage between the neutral line and the second phase transmission line between the third instrument current transformer and the fourth instrument current transformer on the electrical circuit, and the medium And a voltage to transform the voltage between the third phase power transmission line between the fifth instrument current transformer and the sixth instrument current transformer on the electrical line and the electric circuit so that the voltage can be measured. Transforming means;
Transformer for two-way measuring instrument equipped with. A bidirectional power metering system used for metering bidirectional power and reactive power in a three-phase four-wire transmission line,
A first instrument current transformer and a second instrument current transformer connected to the first phase power transmission line of the three-phase four-wire power transmission line;
A third instrument current transformer and a fourth instrument current transformer connected to the second phase power transmission line of the three-phase four-wire power transmission line;
A fifth instrument current transformer and a sixth instrument current transformer connected to the third phase power transmission line of the three-phase four-wire power transmission line;
Between the neutral line of the three-phase four-wire transmission line and the first-phase transmission line between the first instrument current transformer and the second instrument current transformer on the electric circuit. A voltage, a voltage between the neutral line and the second phase transmission line between the third instrument current transformer and the fourth instrument current transformer on the electrical circuit, and the medium And the voltage between the third phase power transmission line between the fifth instrument current transformer and the sixth instrument current transformer on the electrical line and the electric circuit so that they can be measured. Voltage transformation means;
Two-way power metering system with

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