JP2678258B2 - Power system voltage / reactive power control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a voltage of a power system (hereinafter referred to as a system).
The present invention relates to a reactive power control method, and more particularly to a control method having a function of correcting a system characteristic constant suitable for improving control accuracy.

[Conventional technology]

Conventionally, voltage / reactive power control in grids is a device that automatically controls taps of transformers and phase-modulating equipment to maintain target values of bus voltage and bank passing reactive power in ultra-high voltage substations and step-up transformers in thermal power plants. By controlling the tap of the above, the voltage at the power transmission end and the reactive power output are maintained at the target values. Regarding the voltage and reactive power control, see Technical Report (Part II) of the Institute of Electrical Engineers of Japan.
No. 73 (1979), pages 36 to 70, are discussed.

[Problems to be solved by the invention]

According to the above-mentioned conventional method, the voltage / reactive power control devices are installed in a distributed manner, and when the number of devices is small, the devices can operate in a coordinated manner. Driving sometimes became difficult.

In addition, when controlling the system with a computer system, a model that simulates the system by connecting nodes and branches is used, but after the control calculated by calculation due to the error of the constant given to the model and the error at the time of calculation There was a problem in accuracy such as the estimated value and the actual measured value after control did not match.

An object of the present invention is to accurately adjust the voltage / reactive power at each point of the power system while coordinating the voltage / reactive power control device.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention relates to a voltage / reactive power control method of a power system, and a system characteristic constant indicating the influence of the operation of a voltage / reactive power control device on the voltage / reactive power of the power system. Predictive control operation of the voltage / reactive power control device based on the following, to obtain the actual voltage / reactive power value of the power system after this operation, the predictive control device and the actual voltage
It is characterized in that the system characteristic constant is corrected by the deviation from the reactive power value.

That is, in the present invention, the system characteristic constant used in performing the electric / reactive power control is an estimated value of the change that one operation of the control device gives to the voltage / reactive power at each point of the power system. Focusing on the fact that the error can be corrected by the actual measurement value obtained later, the correction is made to give the system characteristic constant a learning function to improve the control accuracy.

Here, the learning function of the system characteristic constant will be described below. In order to introduce the control of voltage / reactive power at each point in the system to the computer system, the system characteristic constants showing the effect of one operation of the control device in the system on the voltage / reactive power at each point in the system are calculated for the control amount. To use. This system characteristic constant is a constant given by a function of the impedance of the system only when considered approximately. For example, considering the two-machine system of FIG. Therefore, the voltage E and the reactive power Q are expressed as E = ₁ (P, n, y, E ₁ , E ₂ ) ... (3) Q = ₂ (P, n, y, E ₁ , E ₂ ) ... (4) Then Is obtained and expressed in the form of change, ΔE = A · Δn + B · Δy (7) ΔQ = C · Δn + D · Δy (8), and these A, B, C and D are system characteristic constants. A is the relationship of the change ΔE of the voltage E with respect to the tap operation amount Δn of the transformer, and C is the change Δ of the reactive power Q with respect to the tap operation amount Δn.
Indicates the relationship of Q. B is the relationship of the voltage change ΔE with respect to the manipulated variable Δy of the phase-modulating equipment y, and D is the manipulated variable Δy of the phase-modulating equipment y.
Is a constant representing the relationship of the change ΔQ of the reactive power with respect to. Since the influence of active power on these system characteristic constants A, B, C, D cannot be ignored in practice, the voltage E and reactive power Q can be calculated from equations (1) and (2). And each system characteristic constant is expressed as follows.

If E ₁ = E ₂ ≈1, n≈1, X ₁ X ₂ y ≈0 Becomes Similarly, Becomes The above is extended to the multi-machine system, and the system characteristic constant is obtained from the system impedance.

The control amount calculation is performed by using the system characteristic constant obtained by the above method. Considering now that the adjusting device i is operated in the direction of increasing by one unit (+), the voltage V _j ⁺ at the j-th point and the reactive power Q _k ⁺ at the k-th point in the system change as follows.

V _j ⁺ = V _j + D _ij (16) Q _k ⁺ = Q _k + B _ik (17) Here, the decision function for _keeping V and Q within the operation allowable range is Then, the decision function E ⁺ after the operation is Therefore, the change amount ΔE _i ⁺ of the decision function at this time is Becomes here Then, the change amount ΔE _i ⁺ of the determination function is ΔE ₁ ⁺ = α1-β _i (23). Similarly, the change amount ΔE _i ⁻ of the determination function when one unit is operated in the lowering direction (−) is ΔE _i ⁻ = α _i −β _i (24). β _i is an amount that does not change, but α _i changes depending on the control deviations ΔV and ΔQ. In order to minimize the decision function, ΔE _i ⁺ = −α _i −β _i … (25) ΔE _i ⁻ = α _i −β _i … (26) is calculated for all adjusting devices i, and that is the maximum. Choose a control device that The control device i selected here is the optimum control device. This calculation is repeated to obtain the combination of the control device and the control amount that minimizes the judgment function E.

The control is executed based on the control device and the operation amount selected and determined as described above. After the control is executed, it is monitored that the control target devices have the device values according to the control wholesale command, and the voltage and reactive power value at the time when all the devices have the device values according to the command are collected. In the system characteristic constant correction calculation, the operation characteristic voltage / reactive power predicted value calculated by the control amount calculation and the actual voltage / reactive power value after operation collected online are used to correct the system characteristic constant using the following formula.

This expression (27) realizes the learning effect of the system characteristic constant, which is the center of the present invention.

[Action]

According to the present invention, the voltage / reactive power deviating from the monitored value in the system is brought close to the target value by the control amount calculation, so that the most effective control device is selected and the control amount is calculated. . As a result, the coordination of the control devices in the system is maintained.

The system characteristic constant correction calculation collects the voltage / reactive power values that are the results of executing control in the actual system according to the selection of the control device calculated by the control amount calculation and the control amount, and after the control calculated by the control amount calculation. Calculate the error from the estimated value. Since the system characteristic constant, which is the basic data for the control amount calculation, is corrected based on this error, the accuracy of the next control amount calculation is improved.

〔Example〕

Next, an embodiment according to the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. This embodiment shows an example in which the power system is monitored and controlled by a computer system via a remote monitoring device.

Binary data indicating the connection status of devices input to the computer system through the remote monitoring device 200 and numerical data such as voltage value and reactive power value are monitored by the system monitoring program 301 for occurrence of state change and numerical monitoring violation. . When the state change of binary data occurs, the system monitoring program 301 activates the system characteristic constant calculation 308. The system characteristic constant calculation 308 reconstructs the model system using the latest binary data input through the remote monitoring device 200, then calculates the system characteristic constant and stores it in the system characteristic constant file 307.
When the system monitoring program 301 detects a monitoring violation in voltage / reactive power, it activates the control amount calculation 302. The control amount calculation 302 is the most effective for bringing the violation value close to the target value from the latest equipment value of the system (tapping value of transformer, number of input of phase adjusting equipment, etc.), voltage / reactive power value and system characteristic constant 307. The control device selection and control amount are calculated and stored in the control device / control amount file. At the same time, the voltage
The reactive power estimation value 305 is calculated and stored in the control estimation value file. The control amount calculation 302 starts the control execution program 304 after executing the above. The control execution program 304 sends a control signal to the remote monitoring device 200 based on the data of the control device / control amount file. After the control signal is transmitted, the system monitoring program 301 monitors that the device to be controlled has a device value as controlled. The voltage / reactive power value at the time when the device value is controlled is stored in the control result file, and the system characteristic constant correction calculation 306 is started. The system characteristic constant correction calculation 306 gives a learning effect by correcting the system characteristic constant in the system characteristic constant file from the post-control estimated value file and the control result file.

In this embodiment, the voltage of the high precision voltage
Reactive power control is possible. Further, regardless of the result of monitoring the voltage / reactive power value, the system characteristic constant coefficient 308 is performed when the state change of the binary data occurs, that is, when the system configuration changes. The calculation of system characteristic constants is not required, which has the effect of enabling quick control.

According to the above-described embodiment, the operation of the control device can be minimized in consideration of the state of the power system in a wide area, and the operation of the control device can be minimized. Therefore, the life of the control device can be extended and the economical efficiency can be improved. Has the effect of increasing

Further, even when the model system includes an error, the system characteristic constant including the error is corrected by the result of the actual control, so that there is an effect of improving the control accuracy.

In a typical local power station, there are several to a dozen or more control devices for controlling voltage and reactive power. To select the optimum adjustment device from these control devices and determine the control amount, Since a system operator's experience is required, training and experience have been accumulated in order to train the system operator. However, according to the present invention, even an inexperienced system operator can be experienced in system operation. It is possible to keep the error within a few percent of the target voltage / target reactive power by the same voltage / reactive power control as the user.

If the impedance includes an error when the initial value of the system configuration is given, an error occurs in the system constant calculated by the system characteristic constant calculation. This system constant causes an error in the control result, and in the vicinity of the point where the impedance including the error is given, a deviation of about 10% may occur between the post-control estimated value and the actual control result. is there. On the other hand, the present invention has a function of eliminating the error included in the system constant by the learning method. Therefore, the calculation and control are repeated regardless of the initial value of the given system configuration. Therefore, the control error can be suppressed within a few percent.

Next, FIG. 3 shows an example in which the two-machine system of FIG. 1 is brought closer to the actual system. The on / off state of the switches 1 to 12 of this system, the reactive power amount, the voltage, the tap value of the transformer 14 and the like are collected by the remote monitoring device of FIG. 1, and the on / off states of the switches 1 to 12 are Binary, other values are taken into the computer system as numerical values. In FIG. 3, the reactive power amount Q at the reactive power monitoring point A is Q = Q ₁ −Q ₂ + Q ₃ , but the reactive power amount Q at the monitoring point A when the load is disconnected by opening the switch 12. ′ Becomes Q ′ = Q ₁ −Q _{2 and} decreases by Q ₃ . The case where Q ′ deviates from the allowable range of the target value at the point A due to the decrease of Q ₃ minutes will be described below.

The information that the connection of the load is disconnected by opening the switch 12 is taken into the computer as binary information of the switch 12 by the remote monitoring device of FIG. From this binary information, the system monitoring program detects a change in the state of the switch 12, and starts system characteristic constant calculation assuming that the system configuration has changed. In the system characteristic constant calculation, the system characteristic constants are calculated by the formulas (12) to (15), stored in the system characteristic constant file, and the control amount calculation is started. The control amount calculation is shown in Fig. 4 of the phase adjusting capacitors SC1, SC2,
The effect of the reactive power at the monitoring point A on the connection or disconnection of the phase-shifting reactors SR1, SR2, SR3 is calculated using equations (21) to (26), and the flow chart in Fig. 5 is followed. Select the most suitable adjustment device. When the deviation between the target value of the reactive power amount monitoring point A and Q'is Qd, the amount by which the reactive power amount of the monitoring point A is increased by disconnecting SC1 which absorbs the reactive power from the grid is Qc, It is assumed that the increasing amount of the reactive power at the monitoring point A is Qr due to the connection of any one of the phase-shifting reactors SR1, SR2, and SR3 that generate the reactive power to the grid. At this time, if Qd−Qc> Qd−Qr target value tolerance range ≧ Qd−Qr, the phase-matching reactors SR1, SR2, and SR3 are judged as the optimum control devices, and the device with the number assigned to each device is selected. . Assuming that the phase-shifting reactor SR1 is selected as the control device, (6, OFF → ON) is stored in the control device / control amount file of FIG. 1 as a result of the control amount calculation. After calculating the control device and control amount, the control amount calculation is the reactive power Q at point A when the selected control device (phase modifying reactor) SR1 is connected.
After calculating e and storing it as the post-control estimated value in the post-control estimated value file, the control execution program is started. The control execution program extracts the control device and the control amount from the control device / control amount file, and sends them to the remote monitoring device (switch 6,
Information). The remote monitoring device changes the switch 6 of the actual system from the off state to the on state by the information of (switch 6, on) sent from the control execution program. After a certain time (10 to 30 seconds) has passed from the sending of the control information of the control execution program, the reactive power amount at the monitoring point A is stored in the control result file and the system characteristic constant correction calculation is started. When the impedance given as the initial value data of the system and the ideal value that does not include error in the control equipment are the same as the estimated value after control, the impedance and control given as the initial data of the system are generally used. Due to the error contained in the equipment, the control result and the estimated value after control do not match at a certain value. Based on this error, the system characteristic constant correction calculation is corrected according to the system characteristic constant (27) equation stored in the system characteristic constant file. In the next control amount calculation, the corrected system characteristic constant is used, so that the calculation accuracy is improved. This is the learning effect given by the system characteristic constant correction calculation.

Conventionally, in Fig. 4, SC1, SC2, SR1 and SR are used as adjustment devices when the target value of the reactive energy at monitoring point A deviates.
It was the system operator who decided which of 2 or SR3, and the decision method depended on the experience, so accurate control could not be expected. According to the present invention, the system operator is freed from the work of selecting the adjusting device, and there is an effect that highly accurate control by the computer can be obtained.

〔The invention's effect〕

As described above, according to the present invention, it is possible to accurately adjust the voltage / reactive power at each point of the power system while coordinating the voltage / reactive power control device in the power system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
Diagram showing an electric power system model consisting of the power source of the machine, FIG. 3 is a system diagram showing an example of an actual two-machine system model, FIG. 4 is a system diagram showing another two-machine system model example, and FIG. It is a flow chart showing a calculation flow. 100 ... power system, 200 ... remote monitoring device, 300 ... calculation system.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Morita 5-2-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Omika factory (72) Inventor Koichi Ishizuka 3-7, Ichibancho, Sendai-shi, Miyagi No. 1 Tohoku Electric Power Company (72) Inventor Yoshihiko Sato 3-7-1, Ichibancho, Sendai City, Miyagi Prefecture Tohoku Electric Power Co. (72) Inventor Tetsuji Ogawa 2 Iwatokita, Komae City, Tokyo 11-1 (56) Reference JP-A-60-241726 (JP, A)

Claims (1)

(57) [Claims] 1. A voltage / reactive power control method for controlling a voltage / reactive power of a power system to a target value by using a plurality of voltage / reactive power control devices dispersedly installed in a power system. Predictive control operation of the voltage / reactive power control device based on a system characteristic constant indicating the influence of the operation of the control device on the voltage / reactive power of the power system, and a predictive control value related to the predictive control operation, and its prediction The deviation between the actual voltage and the reactive power value of the power system after the control operation is obtained, and the system characteristic constant is corrected based on this deviation,
In the predictive control operation, the control result of the voltage / reactive power of the power system in the case of controlling by the predictive control value for each of the voltage / reactive power control equipment is estimated, and the estimated value obtained by this estimation and the target value are Of the deviation of each of the voltage / reactive power control equipment, select the voltage / reactive power control equipment having the smallest judgment function based on the deviation, using the selected voltage / reactive power control equipment,
A voltage / reactive power control method for a power system, wherein the predictive control operation is performed based on the predictive control value corresponding to the voltage / reactive power control device.