JP2001215246A - Electronic watt-hour meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic watt-hour meter with a good characteristic of unbalanced load, realizing a small size, a low price, and low power consumption, and capable of employing measurement items corresponding to various charge systems. SOLUTION: The outputs of voltage detectors 109 to 111 are multiplied by the outputs of current detectors 112 to 114, respectively, by using multiplying circuits 201 to 203, added up and integrated by an adding circuit 204, and displayed on an active watt-hour display 205. Reactive watt-hour is computed from outputs obtained by 90 deg. shifting the phases of the outputs of the detectors 109 to 111 by using voltage phase shifters 206 to 208 and from the outputs of the detectors 112 to 114, and displayed on a reactive watt-hour display 213. A power factor computed by a power factor computing circuit 214 is displayed on a power factor display 215. This electronic watt-hour meter with a small size, a low price, and low power consumption, can be realized by this configuration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic watt-hour meter applicable to the measurement of watt-hour in a V-connection three-phase four-wire system of different capacity (that is, a three-phase four-wire system for a △ circuit).

[0002]

2. Description of the Related Art Conventionally, as a watt-hour meter of this type, FIG.
And a configuration as shown in FIG. 7 are known. That is, the current coil 601 and the voltage coil 604 shown in FIG.
The electric energy is measured by the current coil 602 and the voltage coil 605, and the current coil 603 and the voltage coil 606, respectively, as an inductive watt-hour meter. As shown in FIG. The moving magnetic flux is created by synthesizing the magnetic flux generated by the coil 607 (corresponding to each of the current coils 601 to 603) and the voltage coil 608 (corresponding to each of the voltage coils 604 to 606), thereby rotating the rotating disk 609. Electricity is being measured.

[0003]

However, when a multi-element wattmeter is constructed in this manner, a plurality of elements are
When placed in two housings, the effect of magnetic flux interference between the elements is large,
It is difficult to reduce the error in the unbalanced load with respect to the balanced load, and, even when a plurality of elements are appropriately separated from each other so as not to cause mutual interference, the adjustment process becomes complicated, It is not suitable for measuring an unbalanced load such as V-connection of different capacity.

In the case of a multi-element device, the burden on each element increases, and the power consumption increases. Furthermore, when measuring the reactive power, or when measuring the three-phase load and the single-phase load individually, it is necessary to combine a large number of watt-hour meters. there were.

[0005] The present invention has been made in view of the above,
The purpose is to achieve good unbalanced load characteristics, small size, low price, and low power consumption by the electronic measuring method.
An object of the present invention is to provide an electronic watt-hour meter capable of adopting measurement items corresponding to various fee systems.

[0006]

To solve the above-mentioned problems, an electronic watt-hour meter according to the present invention according to claim 1 is provided.
A four-element input terminal connected to a power supply by three-phase four-wire distribution, a four-element output terminal connected to a three-phase three-wire load and a single-phase three-wire load collectively, and first to fourth elements of the four-element input terminal First to fourth electric wires from the four input elements to the first to fourth output elements of the four element output terminals, and the first to third electric currents respectively detecting the currents flowing through the first to third electric wires. A current detector; first to third voltage detectors for detecting voltages of the first to third wires with respect to a fourth wire; outputs of the first to third current detectors and first to third voltages; A multiplying circuit for multiplying the output of the third voltage detector, and an adding circuit for adding and integrating outputs of the first to third multiplying circuits to calculate an active power amount. Is the gist.

In the first aspect of the present invention, since the voltage detector and the current detector are not influenced by each other,
It is easy to realize constant characteristics irrespective of a balanced load or an unbalanced load, the adjustment process can be simplified, and a different-capacity V-connection three-phase four-wire wattmeter can be provided at low cost. Further, the current consumption of the voltage detector and the current detector is almost negligible as compared with the voltage coil and the current coil, so that a watt hour meter with low power consumption can be realized.

According to a second aspect of the present invention, there is provided the electronic watt-hour meter according to the first aspect, wherein the first to third voltage detectors each change the phase of the output of the first to third voltage detectors by 90 degrees.
A first to third reactive power multiplier circuits for multiplying the outputs of the first to third voltage phase shifters by the outputs of the first to third current detectors, respectively; The gist of the invention is to provide a reactive power addition circuit for adding and integrating outputs of the first to third reactive power multiplier circuits to calculate a reactive power amount.

According to the second aspect of the present invention, since the reactive power can be calculated by adding a voltage phase shifter, both the active power and the reactive power can be measured. The watt hour meter can be provided without being enlarged.

According to a third aspect of the present invention, in the electronic watt-hour meter according to the second aspect, the power factor is calculated from the output of the addition circuit for calculating the active power and the output of the addition circuit for the reactive power. The gist of the present invention is that a power factor calculation circuit is provided.

According to the third aspect of the present invention, the calculation of the power factor from the active power amount and the reactive power amount can be easily realized by calculation because of the electronic type.

According to a fourth aspect of the present invention, there is provided an electronic watt-hour meter according to the present invention, which includes a four-element input terminal connected to a three-phase four-wire power supply, a three-phase three-wire load, and a single-phase three-wire load. And the first to third of the four-element input terminal connected to the
The first to third wires from the input element to the first to third output elements of the six-element output terminal, respectively, and the second to fourth input elements of the four-element input terminal to the fourth output element to the six-element output terminal
Fourth to sixth electric wires respectively reaching the first to sixth output elements, first to fifth current detectors for detecting currents flowing through the first to fifth electric wires, respectively, and first to third electric wires A first to a third voltage detector for detecting a voltage between the first and third electric wires, and an output of the first to third current detectors and an output of the first to third voltage detectors. First to third multiplying circuits for multiplying, respectively, fourth and fifth multiplying circuits for multiplying outputs of the fourth and fifth current detectors and outputs of the second and third voltage detectors, respectively. A three-phase three-wire load-side addition circuit that adds and integrates the outputs of the first to third multiplication circuits to calculate an active power amount in the three-phase three-wire load;
Adding and integrating the outputs of the fourth and fifth multiplication circuits;
The gist of the present invention is to include a single-phase three-wire load-side adder circuit for calculating an active power amount in a single-phase three-wire load.

According to the fourth aspect of the present invention, the different capacitance V
In the connection and distribution, it is possible to provide a watt hour meter capable of separately measuring a three-phase three-wire side load and a single-phase three-wire side load with one watt-hour meter.

According to a fifth aspect of the present invention, in the electronic watt-hour meter according to the fourth aspect, the output of the three-phase three-wire load-side addition circuit and the output of the single-phase three-wire load-side addition circuit are added. The gist is to provide a three-phase / single-phase addition circuit.

According to the present invention, the three-phase three-wire load and the single-phase three-wire load can be measured separately and simultaneously.

According to a sixth aspect of the present invention, there is provided the electronic watt-hour meter according to the fourth aspect, wherein the outputs of the first to third voltage detectors are respectively changed in phase by 90 degrees.
And a first to third three-phase three-wire-side reactive power multiplying the outputs of the first to third voltage phase shifters and the first to third current detectors, respectively. A multiplication circuit, a three-phase three-wire-side reactive power addition circuit for adding and integrating outputs of the first to third three-phase three-wire-side reactive multiplication circuits to calculate a reactive power amount in the three-phase three-wire load; A fourth and fifth single-phase three-wire-side reactive power multipliers for multiplying the outputs of the second and third voltage phase shifters and the outputs of the fourth and fifth current detectors, respectively; And a single-phase three-wire reactive power adder circuit for adding and integrating outputs of the fifth single-phase three-wire reactive multiplying circuit and calculating a reactive power amount at the single-phase three-wire load. And

According to the present invention, it is possible to separately measure the amount of reactive power on the three-phase three-wire load side and the single-phase three-wire load side.

According to a seventh aspect of the present invention, in the electronic watt-hour meter according to the sixth aspect, the output of the three-phase three-wire load side addition circuit and the output of the three-phase three-wire side reactive power addition circuit are provided. From the output of the single-phase three-wire load-side adder circuit and the output of the single-phase three-wire-side reactive power adder The present invention further includes a single-phase three-wire load-side power factor calculation circuit that calculates a single-phase three-wire load-side power factor.

According to the seventh aspect of the invention, it is possible to separately measure the power factor on the three-phase three-wire load side and the single-phase three-wire load side.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following drawings, the same symbols indicate the same or corresponding parts.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of an electronic type variable-capacity V-connection three-phase four-wire watt-hour meter according to the embodiment of FIG. 2, and FIG.

In FIG. 1, power supplied by different capacity V connection distribution is a four-element input terminal (1S) 101, a four-element input terminal (2S) 102, and a four-element input terminal of a three-phase four-wire wattmeter. (3S) 103 and a four-element input terminal (0
S) 104 is connected. Among the four element output terminals of the three-phase four-wire watt-hour meter, a four element output terminal (1L) 105, a four element output terminal (2L) 106, and a four element output terminal (3
L) 107 is connected to a three-phase three-wire load, and outputs four-element output terminal (2L) 106 and four-element output terminal (3).
L) 107 and a four-element output terminal (0L) 108 are connected to a single-phase three-wire load.

In FIG. 2, a voltage detector (V1) 109 to a voltage detector (V3) 11 provided individually for each element are shown.
1, and the current detector (I1) 112 to the current detector (I
3) The output result of 114 is multiplied for each element by the multiplication circuits (X1) 201 to (X3) 203, and the results are added and integrated by the addition circuit 204. The active electric energy is displayed on the active electric energy display 205 according to the output of the adding circuit 204.

The outputs of the voltage detector (V1) 109 to the voltage detector (V3) 111 are output from the voltage phase shifter (Φ1) 206 to
After the phase shift is changed by 90 degrees by the voltage phase shifter (Φ3) 208, the current detector (I1) 112 is supplied to the reactive power multiplier (X4) 209 to the reactive power multiplier (X6) 211.
と と も に is input together with the output of the current detector (I3) 114.

The outputs of the reactive power multiplier (X4) 209 to the reactive power multiplier (X6) 211 are input to the reactive power adder 212 and added and integrated. The output of the reactive power addition circuit 212 is displayed on a reactive power indicator 213.

The output of the adding circuit 204 and the output of the reactive power adding circuit 211 are input to a power factor calculating circuit 214. The power factor obtained by the power factor calculation circuit 214 is a power factor indicator 215
Will be displayed.

According to the first embodiment, the voltage detector (V1) 109 to the voltage detector (V3) 111, and the current detector (I1) 112 to the current detector (I3) 114
Are not affected by each other, it is easy to realize constant characteristics regardless of balanced load and unbalanced load, and the adjustment process can be simplified. V-connection three-phase four-wire watt-hour meter with different capacity Can be realized at a low price. Further, a voltage detector (V1) 10
9 to the voltage detector (V3) 111 and the current detector (I
1) The current consumption of the current detector (I3) 112 can be almost ignored as compared with the voltage coil and the current coil, and it is possible to realize a watt hour meter with low power consumption.

Also, since the reactive power can be calculated by using the voltage phase shifters (Φ1) 206 to the voltage phase shifter (Φ3) 208, the power that can measure both the active power and the reactive power can be calculated. This can be realized without increasing the size of the meter.

Further, the power factor can be easily calculated by the power factor calculation circuit 214 from the active power amount and the reactive power amount.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
FIG. 4 is a diagram showing a configuration of an electronic type variable capacity V-connection three-phase four-wire watt-hour meter according to the embodiment of the present invention, and FIG. 4 is a diagram showing a calculation part thereof and a display.

In FIG. 3, the power supplied by different capacity V connection distribution is a four-element input terminal (1S) 101, a four-element input terminal (2S) 102, and a four-element input terminal of a three-phase four-wire wattmeter. (3S) 103 and a four-element input terminal (0
S) 104 is connected. Among the six element output terminals of the three-phase four-wire watt-hour meter, the six element output terminal (1L) 301, the six element output terminal (2L) 302, and the six element output terminal (3
L) 303, a three-phase three-wire load is connected, and a six-element output terminal (2L ') 304 and a six-element output terminal (3L') 3
A single-phase three-wire load is connected to the 06 and 6 element output terminals (0L) 305.

In FIG. 4, the voltage detector (V1) 307 to the voltage detector (V3) 30 provided individually for each element are shown.
9, and the current detector (I1) 310 to the current detector (I
3) The output result of 312 is multiplied for each element by a multiplication circuit (X1) 401 to a multiplication circuit (X3) 403, and the result is added and integrated by a three-phase three-wire load-side addition circuit 406. The active power on the three-phase three-wire load side is displayed on the three-phase three-wire load side display 408 according to the output of the three-phase three-wire load side addition circuit 406.

The outputs of the voltage detector (V1) 307 to the voltage detector (V3) 309 are output from a voltage phase shifter (Φ1) 410 to
After the phase shift is changed by 90 degrees by the voltage phase shifter (Φ3) 412, the current detector (I1) 310 is supplied to the reactive power multiplier (X6) 413 to the reactive power multiplier (X8) 415.
と と も に is input together with the output of the current detector (I3) 312.

The outputs of the reactive power multiplier (X6) 413 to the reactive power multiplier (X8) 415 are input to the three-phase three-wire reactive power adder 418 and added and integrated. The output of the three-phase three-wire reactive power addition circuit 418 is displayed on the three-phase three-wire reactive power indicator 420.

The output of the three-phase three-wire load-side addition circuit 406 and the output of the three-phase three-wire reactive power addition circuit 418 are input to the three-phase three-wire load-side power factor calculation circuit 422. The power factor obtained by the three-phase three-wire load-side power factor calculation circuit 422 is displayed on the three-phase three-wire load-side power factor display 424.

The voltage detector (V2) 308, the voltage detector (V3) 309, and the current detector (I2 ') 313
The output of the current detector (I3 ′) 314 is multiplied for each element by a multiplier (X4) 404 and a multiplier (X5) 405, and the result is added and integrated by a single-phase three-wire load-side adder 407. Is done. The single-phase three-wire load-side active power amount is displayed on the single-phase three-wire load-side display 409 according to the output of the single-phase three-wire load-side addition circuit 407.

The outputs of the voltage phase shifter (Φ2) 411 and the voltage phase shifter (Φ3) 412 are supplied to the reactive power multiplier (X
9) 416 and reactive power multiplier (X10) 417
The current detector (I2 ′) 313 and the current detector (I2
3 ') The output is input together with the output of 314. The outputs of the reactive power multiplier circuit (X9) 416 and the reactive power multiplier circuit (X10) 417 are input to the single-phase three-wire-side reactive power adder circuit 419, where they are added and integrated. The output of the single-phase three-wire reactive power addition circuit 419 is displayed on the single-phase three-wire reactive power indicator 421.

The output of the single-phase three-wire load side adder 407 and the output of the single-phase three-wire reactive power adder 419 are input to a single-phase three-wire load-side power factor calculator 423. The power factor obtained by the single-phase three-wire load-side power factor calculation circuit 423) is displayed on the single-phase three-wire load-side power factor display 425.

According to the second embodiment, in the different capacity V connection distribution, the three-phase three-wire load and the single-phase three-wire load are set to one.
It is possible to realize a watt-hour meter that can be separately measured by two watt-hour meters. It is also possible to separately measure the amount of reactive power on the three-phase three-wire load side and the single-phase three-wire load side. Further, it is possible to separately measure the power factor on the three-phase three-wire load side and the power factor on the single-phase three-wire load side.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
It is a figure which shows the calculation part and display of the electronic different capacity V connection three-phase four-wire watt-hour meter which concerns on embodiment of FIG.

The output of the three-phase three-wire load-side addition circuit 406 and the output of the single-phase three-wire load-side addition circuit 407 are input to the three-phase / single-phase addition circuit 501, and the three-phase three-wire load side and the single-phase three-wire The power consumption of the load side is displayed on the three-phase single-phase display 502.

According to the third embodiment, a watt-hour meter capable of separately measuring a three-phase three-wire load and a single-phase three-wire load and simultaneously measuring the same in V-connection distribution with different capacities is provided. Can be realized.

[0043]

As described above, according to the present invention, the unbalanced load characteristic is excellent in the power supply equipment of the different capacity V-connection three-phase four-wire distribution system with many unbalanced load operations.
It is possible to realize an electronic watt-hour meter that is small in size, low in cost and low in power consumption, and that can employ measurement items corresponding to various fee structures.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a different-capacity V-connection three-phase four-wire electronic wattmeter according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a calculation part and a display of the different capacity V connection three-phase four-wire electronic watt-hour meter shown in FIG.

FIG. 3 is a diagram illustrating a configuration of a different-capacity V-connection three-phase four-wire electronic wattmeter according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a calculation part and a display of the different capacity V connection three-phase four-wire electronic watt-hour meter shown in FIG. 3;

FIG. 5 is a diagram showing a calculation part and a display of a different capacity V connection three-phase four-wire electronic watt-hour meter according to a third embodiment of the present invention.

FIG. 6 is a diagram showing the configuration of a conventional different-capacity V-connection three-phase four-wire watt-hour meter.

FIG. 7 is a diagram showing a structure of a conventional inductive watt-hour meter.

[Explanation of symbols]

101, 102, 103, 104 ... 4 element input terminals 105, 106, 107, 108 ... 4 element output terminals 109, 110, 111 ... voltage detectors 112, 113, 114 ... current detectors 201, 202, 203 ... multiplication circuits 204: Addition circuit 205, 206, 207: Voltage phase shifter 208, 209, 210: Reactive power multiplication circuit 211: Reactive power addition circuit 212: Power factor calculation circuit 213: Active power amount display 214: Reactive power amount Display 215 ... Power factor display 301, 302, 303, 304, 305, 306 ... 6
Element output terminals 307, 308, 309: voltage detectors 310, 311, 312, 313, 314: current detectors 401, 402, 403, 404, 405: multiplication circuit 406: three-phase three-wire load-side addition circuit 407: single Phase 3-wire load-side addition circuit 408: 3-phase 3-wire load-side display 409 ... Single-phase 3-wire load-side display 410, 411, 412 ... voltage phase shifter 413, 414, 415, 416, 417 ... for reactive power Multiplying circuit 418 ... Addition circuit for three-phase three-wire reactive power 419 ... Single-phase three-wire reactive power adding circuit 420 Three-phase three-wire reactive power indicator 421 ... Single-phase three-wire reactive power indicator 422 ... three-phase three-wire load-side power factor calculation circuit 423 ... single-phase three-wire load-side power factor calculation circuit 424 ... three-phase three-wire load-side power factor display 425 ... single-phase three-wire load-side power factor display 501 ... three Phase single-phase addition circuit 502 ... Three-phase single-phase display 601, 602, 603, 607 ... current coil 604, 605, 606, 608 ... voltage coil 609 ... rotating disk 610 ... braking magnet 611, 612 ... input terminal 613, 614 ... output terminal 615 ... upper bearing 616: Lower bearing 617: Indicator

Claims (7)

[Claims] 1. A four-element input terminal connected to a three-phase four-wire power supply, a four-element output terminal collectively connected to a three-phase three-wire load and a single-phase three-wire load, and the four-element input. The first to fourth electric wires from the first to fourth input elements of the terminals to the first to fourth output elements of the four-element output terminal, respectively, and the currents flowing through the first to third electric wires, respectively. First to third current detectors for detecting, and the first to third current detectors
First to third voltage detectors respectively detecting the voltage of the fourth electric wire with respect to the fourth electric wire, outputs of the first to third current detectors, and outputs of the first to third voltage detectors , And an addition circuit for adding and integrating outputs of the first to third multiplication circuits to calculate an active power amount. Watt hour meter. 2. An electronic watt-hour meter according to claim 1, wherein said outputs of said first to third voltage detectors are respectively 9
A first to third voltage phase shifter for changing the phase by 0 degree, and a first to multiply an output of each of the first to third voltage phase shifters by an output of each of the first to third current detectors. A third reactive power multiplying circuit; and a reactive power adding circuit for adding and integrating outputs of the first to third reactive power multipliers to calculate a reactive power amount. Electronic watt-hour meter. 3. An electronic watt-hour meter according to claim 2, further comprising a power factor calculating circuit for calculating a power factor from an output of said adding circuit for calculating said active power and an output of said adding circuit for reactive power. An electronic watt-hour meter comprising: 4. A four-element input terminal connected to a three-phase four-wire power supply, a six-element output terminal individually connected to a three-phase three-wire load and a single-phase three-wire load, and the four-element input terminal. First
First to third electric wires respectively extending from a third input element to a third output element of the six-element output terminal,
Fourth to sixth wires respectively extending from the second to fourth input devices of the four-element input terminal to fourth to sixth output devices of the six-element output terminal, and the first to fifth wires. A first to a fifth current detector for detecting a flowing current, and a first to a third voltage detector for detecting a voltage between the first to third wires and the sixth wire, respectively. ,
First to third multiplying circuits for multiplying outputs of the first to third current detectors and outputs of the first to third voltage detectors, respectively, and the fourth and fifth current detectors And the outputs of the first and third multiplier circuits are respectively multiplied by the outputs of the second and third voltage detectors. The outputs of the three-phase three-wire load-side addition circuit for calculating the active power under a line load and the outputs of the fourth and fifth multiplication circuits are added and integrated to calculate the active power under a single-phase three-wire load. Single phase 3
An electronic watt-hour meter comprising a line load-side addition circuit. 5. An electronic watt-hour meter according to claim 4, wherein the output of said three-phase three-wire load-side addition circuit and the output of said single-phase three-wire load-side addition circuit are added. An electronic watt-hour meter comprising: 6. An electronic watt-hour meter according to claim 4, wherein outputs of said first to third voltage detectors are respectively 9
A first to third voltage phase shifter for changing the phase by 0 degree, and a first to multiply an output of each of the first to third voltage phase shifters by an output of each of the first to third current detectors. To the third three-phase three-wire reactive power multiplying circuit and the outputs of the first to third three-phase three-wire reactive power multiplying circuits, and to add the reactive power to the three-phase three-wire load. A three-phase / three-wire-side reactive power addition circuit to be calculated; and fourth and fifth multiplying outputs of the second and third voltage phase shifters and outputs of the fourth and fifth current detectors, respectively. And the outputs of the fourth and fifth single-phase three-wire-side reactive multipliers are added and integrated to calculate a reactive power amount with a single-phase three-wire load. An electronic watt-hour meter comprising a phase three-wire-side reactive power addition circuit. 7. An electronic watt-hour meter according to claim 6, wherein a three-phase three-wire load is obtained from an output of said three-phase three-wire load side addition circuit and an output of said three-phase three-wire side reactive power addition circuit. -Phase three-wire load-side power factor calculation circuit for calculating the power factor on the side, and a single-phase three-wire system based on the output of the single-phase three-wire load-side addition circuit and the output of the single-phase three-wire-side reactive power addition circuit An electronic watt-hour meter comprising: a single-phase three-wire load-side power factor calculation circuit that calculates a load-side power factor.