JP5484306B2 - Power measuring device - Google Patents

Description

  The present invention relates to a power measuring device, and more particularly to a power measuring device capable of improving reliability.

  The arithmetic processing unit in the generator monitoring control device as a conventional power measuring device operates as follows. That is, input signals are input from a current transformer attached to the output bus of the generator and a voltage transformer that detects the voltage of the output bus, and the generator current, generator active power, generator reactive power, and electric energy The data of the measurement items such as the power factor can be calculated by the calculation processing unit and displayed on the display unit if necessary (for example, see Patent Document 1).

JP 2004-15971 A (for example, paragraph numbers 0016 and 0017 and FIG. 1)

  The conventional generator monitoring and control system is configured as described above, and it is considered that no special consideration has been given to the power measurement when the instrument transformer cannot be used due to failure, etc., and power measurement is impossible. Therefore, improvement of reliability in the case of failure of an instrument transformer is required.

  The present invention has been made to solve the above problems, and continues power measurement even when any one of the voltage measuring means for measuring the three-phase interphase voltages is determined to be abnormal. An object of the present invention is to obtain a power measuring device that can improve reliability.

In the power measuring apparatus according to the present invention,
A power measurement device comprising a voltage measurement device, a current measurement device, a power conversion device, and an arithmetic device,
The voltage measuring device has voltage measuring means for measuring the interphase voltage of the three-phase AC generator,
The current measuring device has current measuring means for measuring the line current of the three-phase AC generator,
The power conversion device obtains a plurality of patterns of single-phase power based on the interphase voltage and the line current,
The arithmetic device has a voltage measurement means abnormality determination means and a three-phase power calculation means,
The voltage measurement unit abnormality determination unit is configured to determine whether or not the voltage measurement unit is abnormal based on a difference between the single-phase powers of the plurality of patterns.
The three-phase power calculation means obtains three-phase power based on the single-phase power of the plurality of patterns when the voltage measurement means abnormality determination means determines that the voltage measurement means is not abnormal, and the voltage measurement means When the voltage measuring means is determined to be abnormal by the abnormality determining means, two predetermined single-phase powers are selected from the plurality of patterns of single-phase power, and the three-phase power is obtained from the sum thereof.

The present invention is a power measurement device comprising a voltage measurement device, a current measurement device, a power conversion device, and an arithmetic device,
The voltage measuring device has voltage measuring means for measuring the interphase voltage of the three-phase AC generator,
The current measuring device has current measuring means for measuring the line current of the three-phase AC generator,
The power conversion device obtains a plurality of patterns of single-phase power based on the interphase voltage and the line current,
The arithmetic device has a voltage measurement means abnormality determination means and a three-phase power calculation means,
The voltage measurement unit abnormality determination unit is configured to determine whether or not the voltage measurement unit is abnormal based on a difference between the single-phase powers of the plurality of patterns.
The three-phase power calculation means obtains three-phase power based on the single-phase power of the plurality of patterns when the voltage measurement means abnormality determination means determines that the voltage measurement means is not abnormal, and the voltage measurement means When the abnormality determining means determines that the voltage measuring means is abnormal, the predetermined two single-phase powers are selected from the plurality of patterns of single-phase power, and the three-phase power is obtained from the sum thereof.
Even when the voltage measuring means is determined to be abnormal, the power measurement can be continued by calculating the three-phase power from the calculated values of the two predetermined single-phase powers, so that the reliability can be improved.

It is a block diagram which shows the structure of the electric power measurement apparatus which is Embodiment 1 of this invention. 3 is a flowchart for explaining the operation of the arithmetic device in FIG. 1. It is a block diagram which shows the structure of the electric power measurement apparatus which is Embodiment 2. FIG. 4 is a flowchart for explaining the operation of the arithmetic device in FIG. 3. FIG. 10 is a configuration diagram illustrating a configuration of a power measurement device according to a third embodiment. It is a flowchart for demonstrating operation | movement of the arithmetic unit of FIG. It is a block diagram which shows the structure of the electric power measurement apparatus which is Embodiment 4. FIG. It is a flowchart for demonstrating operation | movement of the arithmetic unit of FIG.

Embodiment 1 FIG.
FIG. 1 and FIG. 2 show Embodiment 1 for carrying out the present invention, FIG. 1 is a configuration diagram showing the configuration of a power measuring device, and FIG. 2 is a flowchart for explaining the operation of an arithmetic device. It is. In FIG. 1, a three-phase AC generator 2 is connected to a gas turbine 1 and driven. A voltage measuring device 3 and a current measuring device 4 are connected to the output lines a, b, c of the generator 2. The voltage measuring device 3 includes three single-phase VTs (single-phase instrument transformers) 3a, 3b, 3c as voltage detection means, each of which is between the output lines a, b, c of the generator 2. And the primary side is Δ-connected. In the current measuring device 4, three CTs (instrument current transformers) 4 a, 4 b and 4 c as current detection means are provided on the output lines a, b and c of the generator 2, respectively. Measure the line current of a, b, c. The outputs of the single-phase VTs 3a, 3b, 3c and CTs 4a, 4b, 4c are supplied to the power converters 5a, 5b, 5c of the power converter 5, respectively. The generator control device includes a calculation device 16 and a control device 18. The outputs of the power converters 5a, 5b, 5c are input to the arithmetic device 16. The arithmetic device 16 includes a VT abnormality determining unit 16a and a three-phase power calculating unit 16b as voltage measuring unit abnormality determining units. A control device 18 is connected to the arithmetic device 16.

Next, the operation will be described based on the flowchart of FIG. The interphase voltages Vab, Vbc, and Vca are measured by the single-phase VTs 3a to 3c in which the primary winding side is delta-connected. Further, the line currents Ia, Ib, and Ic of each phase are measured by CT4a to 4c (S11). From the combination of the interphase voltage and the line current by the power converters 5a to 5c, WA1 (Vab × Ia), WA2 (Vba × Ib), WB1 (Vbc × Ib), WB2 (Vcb × Ic), WC1 (Vca × Ic) and WC2 (Vac × Ia) of six patterns of single-phase power are obtained (S12). Assuming that the load of the generator 2 is in a three-phase equilibrium state, the difference between the six patterns of single-phase power is necessarily a measurement error ε (ε is single-phase VT3a, 3b, 3c, CT4a, 4b, 4c, power converter 5a, 5b, 5c, etc. Example: When the device accuracy is ± 5%, ε = 10%) or less, so the VT abnormality determination means 16a uses the line current as a reference for each single-phase power as follows: When the difference is taken and all are equal to or less than the measurement error ε, it is determined that all the single-phase VTs 3a to 3c are not abnormal.
εa = WA1-WC2 = Vab × Ia−Vac × Ia ≦ ε
εb = WA2−WB1 = Vba × Ib−Vbc × Ib ≦ ε
εc = WB2-WC1 = Vcb × Ic−Vca × Ic ≦ ε
Also,
When | εa |> ε and | εb |> ε, the single-phase VT3a is abnormal. | Εb |> ε and | εc |> ε, the single-phase VT3b is abnormal. | Εc |> ε and | εa |> In the case of ε, it is determined that the single-phase VT3c is abnormal (step S13).

In step S13, when it is determined that all of the single-phase VTs 3a to 3c are not abnormal, the three-phase power calculation unit 16b calculates the three-phase power from the sum of the two single-phase powers by any one of the following equations. (Step S14).
W1 = WA1 + WB2
W2 = WC1 + WA2
W3 = WC2 + WB1
Based on the calculated three-phase power, the control device 18 controls the generator 2 (step S16).

If it is determined in step S13 that the single-phase VT3a is abnormal, the following equation W3 = WC2 + WB1
To calculate the three-phase power,
When it is determined that the single-phase VT3b is abnormal, the following equation W2 = WC1 + WA2
To calculate the three-phase power,
When it is determined that the single-phase VT3c is abnormal, the following equation W1 = WA1 + WB2
To calculate the three-phase power (step S15).
Based on the calculated three-phase power, the control device 18 controls the generator 2 (step S16).
That is, based on the other single-phase power (calculated value) (hereinafter referred to as non-abnormal single-phase power) excluding the single-phase power (calculated value) related to the measured value by the single-phase VT determined to be abnormal. Phase power can be calculated. Then, based on the calculated three-phase power, the control device 18 can continue to control the generator 2.

  As a result, even when any one of the single-phase VTs 3a to 3c that measure the three-phase interphase voltage becomes abnormal for some reason and becomes unusable, the single-phase of the remaining two phases that are the predetermined single-phase power The power measurement can be continued by calculating the three-phase power from the calculated value of power by the two-watt meter method, the reliability of the power measuring device can be improved, and the control of the generator 2 is continued, that is, the operation is continued. Is possible.

Embodiment 2. FIG.
3 and 4 show the second embodiment, FIG. 3 is a configuration diagram showing the configuration of the power measuring device, and FIG. 4 is a flowchart for explaining the operation of the arithmetic device. In FIG. 3, the arithmetic unit 26 has alarm means 26a as abnormality alarm means. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted.

As shown in the flowchart of FIG. 4, when the single-phase VT 3 a to 3 c is determined to be abnormal by the VT abnormality determination unit 16 a in step S <b> 13, the arithmetic unit 26 issues a VT abnormality alarm in step S <b> 21 and goes to step S <b> 15. Three-phase power is calculated from single-phase power that is not abnormal. Other operations are the same as those in the flowchart of the first embodiment shown in FIG.
By issuing a warning notifying the abnormality of the single-phase VT based on the abnormality determination result of S13, specifically, for example, warning the operator of the abnormality of the single-phase VT by the generation of a buzzer sound, blinking of the abnormality lamp, etc. Can be aroused.

Embodiment 3 FIG.
5 and 6 show the third embodiment, FIG. 5 is a configuration diagram showing the configuration of the power measuring device, and FIG. 6 is a flowchart for explaining the operation of the arithmetic device. In FIG. 5, the arithmetic unit 36 has an average three-phase power calculation unit 36a as a three-phase power calculation unit. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted.

  In FIG. 7, when the arithmetic unit 36 determines in step S13 that there is no abnormality in the single-phase VT by the VT abnormality determination unit 16a, in step S31, the three-phase power is converted into three patterns of three-phase power (W1 = WA1 + WB2, W2 = WC1 + WA2, W3 = WC2 + WB1). Other operations are the same as those in the flowchart of the first embodiment shown in FIG. Thereby, the reliability of the calculated three-phase power can be improved.

Embodiment 4 FIG.
7 and 8 show the fourth embodiment, FIG. 7 is a configuration diagram showing the configuration of the power measuring device, and FIG. 8 is a flowchart for explaining the operation of the arithmetic device. In FIG. 7, the arithmetic unit 46 includes a VT abnormality determination unit 16a, an alarm unit 26a, and an average three-phase power calculation unit 36a. Since other configurations are the same as those in the third embodiment shown in FIG. 5, the corresponding components are denoted by the same reference numerals and description thereof is omitted.

As shown in the flowchart of FIG. 8, when the single-phase VT 3a to 3c is determined to be abnormal by the VT abnormality determination means 16a in step S13, the arithmetic unit 26 issues a VT abnormality alarm in step S21 and goes to step S15. The three-phase power is calculated based on the single-phase power that is not abnormal. Other operations are the same as those in the flowchart of the third embodiment shown in FIG.
By issuing a warning notifying the abnormality of the single-phase VT based on the abnormality determination result in step S13, the operator can be warned of the abnormality of the single-phase VT and alerted.
Note that the power measuring apparatus according to the present invention is not limited to the generator, and can be widely applied to general power measurement.

1 gas turbine, 2 generator, 3 voltage measuring device,
3a to 3c single-phase VT (instrument transformer), 4 current measuring device,
4a to 4c CT (instrument current transformer), 5 power converter, 5a to 5c power converter,
16, 26, 36, 46 arithmetic unit, 16a VT abnormality determination means,
16b Three-phase power calculation means, 26a Alarm means, 36a Average three-phase power calculation means.

Claims (4)

A power measurement device comprising a voltage measurement device, a current measurement device, a power conversion device, and an arithmetic device,
The voltage measuring device has voltage measuring means for measuring the interphase voltage of the three-phase AC generator,
The current measuring device has current measuring means for measuring the line current of the three-phase AC generator,
The power conversion device obtains a plurality of patterns of single-phase power based on the interphase voltage and the line current,
The arithmetic device has a voltage measurement means abnormality determination means and a three-phase power calculation means,
The voltage measurement unit abnormality determination unit is configured to determine whether or not the voltage measurement unit is abnormal based on a difference between the single-phase powers of the plurality of patterns.
The three-phase power calculation means obtains three-phase power based on the single-phase power of the plurality of patterns when the voltage measurement means abnormality determination means determines that the voltage measurement means is not abnormal, and the voltage measurement means When the abnormality measuring means determines that the voltage measuring means is abnormal, the power measurement is to obtain the three-phase power from the sum of the two selected single-phase powers among the single-phase powers of the plurality of patterns. apparatus. The three-phase power calculation means obtains three-phase power from an average value of the single-phase power of the plurality of patterns when the voltage measurement means abnormality determination means determines that the voltage measurement means is not abnormal, and measures the voltage When the voltage measuring means is determined to be abnormal by the means for determining abnormality, the predetermined two single-phase powers are selected from the plurality of patterns of single-phase power, and the three-phase power is obtained from the sum thereof. The power measuring device according to claim 1. The three-phase power calculation means is configured to calculate from the sum of any two single-phase powers of the plurality of patterns of single-phase power when the voltage measurement means abnormality determination means determines that the voltage measurement means is not abnormal. Three-phase power is obtained, and when the voltage measuring means is determined to be abnormal by the voltage measuring means abnormality determining means, two predetermined single-phase powers are selected from the plurality of patterns of single-phase power and the sum thereof is selected. The power measuring apparatus according to claim 1, wherein three-phase power is obtained. The arithmetic device has a warning means,
The power measuring device according to any one of claims 1 to 3, wherein the alarm means issues an alarm when the voltage measuring means is determined to be abnormal.

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