JP3319616B2 - Substation having operation support function and support method and apparatus therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substation equipped with voltage regulating equipment (tap switching transformer under load), and automatically controls a tap switching transformer by a lifting command so as to maintain a system voltage at a predetermined voltage. More particularly, the present invention relates to a system voltage control device that applies fuzzy inference to tap switching control and a method of supporting the operation.

[0002]

2. Description of the Related Art The voltage of a system is greatly affected by reactive power, such as an increase in power transmission loss due to reactive power of a load when the voltage is constant at a power transmission end.

[0003] Therefore, the conventional device uses reactive power control,
Tap control of a transformer (sometimes abbreviated as LR);
In some cases, power capacitors or shunt reactors installed in substations are connected to or disconnected from the system by turning on and off circuit breakers. This control principle is based on a prediction based on a voltage / reactive power flow pattern determined based on a certain prediction. The deviation from the actual is determined by a transformer tap (sometimes abbreviated as LRT) and a power capacitor for phase adjustment. (Sometimes abbreviated as SC)
The voltage and the reactive power are controlled by correcting by adjusting control of the shunt reactor (sometimes abbreviated as shR).

An example of voltage / reactive power control is shown below. (1) If the voltage is high and the reactive power is large, lower the LRT. (2) If the voltage is high and the reactive power is low, release SC or turn on shR. (3) When the voltage is low and the reactive power is small, LRT
Raise. (4) When the voltage is low and the reactive power is large, the SC is turned on or the shR is released.

[0005] As related to this conventional technology, there is known a proceedings of the National Conference of the Institute of Electrical Engineers of Japan (No. 1002-1
003 pages 9-100 to 9-101).

[0006] As a system voltage control device of this type, although not a known example, there is a voltage adjustment relay as described in Japanese Patent Application No. 3-230723. This device is
A fuzzy controller for inferring a transformation ratio switching control amount, and a device for automatically switching a load tap switching transformer based on a transformation ratio switching control amount signal provided from the fuzzy controller. The fuzzy controller is configured to maintain the system voltage at a voltage specified in advance, based on the detected voltage value on the secondary side of the transformer and the detected current value on the secondary side, and a deviation between the target voltage value and the deviation. A plurality of fuzzy rules using the time integral value as the antecedent variable and the control ratio switching control of the transformer as the consequent variable, and each antecedent variable and consequent variable assigned to each fuzzy label Is used to infer the control ratio for controlling the transformation ratio based on the membership function.

[0007]

In the control of the system voltage, the ideal voltage control means that the average voltage (average error of the system voltage with respect to the target voltage) for a certain time (for example, 30 minutes) is always the reference voltage management. Within a width (for example, ± 2%) and the tap switching frequency is a specified value (for example, 5
0 times / day). The former is a system voltage control target, and the latter is a problem concerning the life of the tap switching mechanism. However, in an actual voltage control device, if the dead zone setting of the device (minimum value of the deviation [system voltage-target voltage] at which the device can operate) and the integration time setting are inappropriate, the control target cannot be achieved, The number of times of switching is extremely increased.

In the above-mentioned prior art, in the voltage / reactive power control device, if the dead zone setting is not appropriate, hunting that repeats the control operation occurs. Therefore, it is necessary to set the dead band width to some extent large with respect to the changing amount of the changing voltage or the reactive power by one control, and an optimum setting value cannot be obtained.

In addition, the voltage regulating relay is provided with a fuzzy control rule for achieving both the system voltage target value and the life target of the tap switching mechanism, and executes fuzzy inference to automatically control the inside of the device. The tap switching control amount is determined. However, in order to determine the membership function assigned to each of the fuzzy rules and the fuzzy labels, it is necessary to repeat trial and error. Japanese Patent Application No. 3-230723 does not refer to a method for determining a control amount.

Further, the substations where the voltage adjustment relays are installed are different for each substation due to the characteristics of the load, and optimal voltage control cannot be performed with one type of fuzzy control rule and membership function. There is a problem that fuzzy control rules and membership functions must be set according to the substation.

[0011] In addition, for a user who operates a substation, for each substation, individual operations such as load characteristics in the area, etc., which are adapted to the individual circumstances of the substation, for example, to emphasize the quality of voltage, It is preferable that the operation can be performed in consideration of individual circumstances, such as a desire to extend the life of the equipment or to intermediate the equipment. However, in practice, such individual operation is difficult, and there is a problem that it is not possible to cope with the demand.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stable supply of electric power, quality improvement, high reliability and long life of equipment, and a unique operation of a user operating a substation. It is an object of the present invention to provide a system voltage control device and a support method for supporting individual operation of a power system.

[0013]

According to the present invention, there is provided, in accordance with the present invention, an on-load tap for maintaining a system voltage at a predetermined voltage in a substation having an on-load tap switching transformer. A voltage control device for controlling the tap switching operation of the switching transformer, and an operation support device for supporting the operation while satisfying individual requirements when operating the voltage control device; The control device is
A control operation unit for performing a voltage control operation for determining a tap switching operation of the on-load tap-changing transformer based on a state of the power system, and an evaluation amount of the state of the power system, and a member corresponding to the evaluation amount A sensitivity correction unit for determining the tap switching operation in the control operation unit by fuzzy inference using the ship function, and sending the sensitivity correction amount to the control operation unit; and the operation support device operates the substation. Request input means for receiving a request from an operator to perform, and for the accumulated system voltage data, in order to optimally determine a tap switching operation in accordance with a preset target voltage and a request from the operator. From the optimal control calculation unit that performs optimal control simulation and the simulation results,
A substation that includes an adjustment amount determining unit that obtains an adjustment amount for adjusting the membership function.

Further, according to the present invention, in a substation including a load tap change transformer, a tap change operation of the load tap change transformer is controlled to maintain the system voltage at a predetermined voltage. Voltage control device,
When operating the voltage control device, the voltage control device includes an operation support device that supports performing the operation while satisfying individual requirements.The voltage control device is configured to control the on-load tap switching transformer based on the state of the power system. A control operation unit that performs a voltage control operation for determining a tap switching operation, and an evaluation amount of a state of a power system, and a tap in the control operation unit by fuzzy inference using a membership function corresponding to the evaluation amount. A sensitivity correction unit for determining the amount of sensitivity correction for determining the switching operation and sending the sensitivity correction amount to the control calculation unit; the operation support device includes: a request input unit that receives a request from an operator who operates the substation; Control simulation for optimally determining the tap switching operation in accordance with the target voltage set in advance and the request from the operator for the voltage data of the And optimal control calculation unit for performing, from the simulation results, the voltage control device, characterized in that it comprises an adjustment amount determining unit for determining an adjustment amount for adjusting the membership function is provided.

Further, according to the present invention, the on-load tap-changing transformer installed in the substation performs a tap-changing operation for maintaining the system voltage at a predetermined voltage by using a fuzzy membership function. An operation support device that supports the operation of a voltage control device that is determined based on the state of the power system with the sensitivity specified by the sensitivity correction amount obtained by inference, and that operates the substation. Request input means for receiving a request from a user, means for creating and storing system voltage data before the current tap switching operation is performed, and setting of a preset target voltage and operation for the stored system voltage data. The optimal control calculation unit that performs the optimal control simulation for optimally determining the tap switching operation in accordance with the request from the user, And an adjustment amount determining unit for determining an adjustment amount for adjusting a membership function, operation support apparatus is provided, wherein the configuring them in the computer.

Further, according to the present invention, for a tap change transformer at load installed in a substation, a tap change operation for maintaining a system voltage at a predetermined voltage is performed by a fuzzy operation using a membership function. Operation to operate a substation when performing control to maintain the system voltage at a specified voltage based on the state of the power system with the sensitivity specified by the sensitivity correction amount obtained by inference. A request from the operator, for the accumulated system voltage data, in accordance with a preset target voltage and a request from the operator, perform an optimal control simulation for optimally determining a tap switching operation, A power system operation support method is provided, wherein an adjustment amount for adjusting the membership function is obtained from a simulation result.

According to another aspect of the present invention, means for collecting and storing system voltage data, user interface means for inputting a user's request value, and a simulation for performing an optimal simulation according to the user's request Means, and means for adjusting membership functions corresponding to fuzzy control rules and fuzzy labels, comprising a general-purpose computer, and provided adjacent to a system voltage control device for maintaining a voltage specified in advance, An electric power system operation support device for transmitting from a general-purpose computer to a system voltage control device is provided.

[0018]

In the power system individualization operation support method having the above-described configuration, first, a request from a user who operates a substation is input. On the other hand, the system voltage is collected, and a non-control system voltage in the case where the on-load tap switching transformer (LRT) tap switching is not performed is created.

Based on this value and the operation results, an optimum value for optimizing a value requested by a user (for example, a peak value of a 30-minute average voltage) from a target voltage determined for each system and for each time. Perform calculations (optimal simulations) online or offline.

In the simulation method, for example, the peak value of the average voltage for 30 minutes is detected, and the most effective tap switching time for reducing the peak value is calculated. This calculation is repeated for the number of times requested by the user.

From the above simulation results, for example,
The peak value of the error is set at the inflection point of the membership function of the fuzzy label of the fuzzy control rule, and the set value is transmitted to the system voltage controller.

Further, the voltage control method equipped with the power system individualization operation support function according to the present invention provides a plurality of fuzzy control rules created in consideration of the voltage fluctuation pattern of the system in accordance with a user's request. A fuzzy label membership function is set so as to obtain characteristics, a fuzzy inference rule is inferred, and a sensitivity coefficient defining a determination value for determining whether or not to switch LRT taps is set by the fuzzy control. Correct with the rule inference result.

As described above, according to the present invention, optimal voltage control can be performed in accordance with the operation style of the user (operator) who operates the power system, and more flexible and individual operation can be performed.

Furthermore, even when the power system is operated, the performance of the voltage control device can be easily changed, and a user-friendly system can be constructed.

[0025]

An embodiment of the present invention will be described below.

FIG. 1 shows an example of the configuration of a substation to which an embodiment of the individualization operation support device and the system voltage control device (voltage / reactive power control device) of the present invention is applied.

In the present invention, the system voltage control device (voltage / reactive power control device) supplies power from the substation to a substation of a low voltage class, and in particular, performs stable voltage control. It is to be. Further, in the present invention, the individualization operation support device supports the voltage control so that the individual operation can be performed in consideration of the situation of the substation.

First, an outline of the overall configuration will be described.

As shown in FIG. 1, a substation to which the present embodiment is applied is disposed between a transmission line 1 and a transmission line 2 and performs an on-load tap change transformer (LRT) 1d for performing voltage adjustment.
And a power capacitor (SC) and a shunt reactor (s
hR), switches SW1 and SW2 for turning on and off the SC and shR, respectively, and a voltage transformer PT on the transmission line 1 side.
1 and a current transformer CT1, a voltage transformer PT2 on the transmission line 2 side on the system secondary side, and the system voltage controller 1 of the present embodiment.
a and an individualization operation support device 1e.

In FIG. 1, the system voltage control device 1a
Voltage transformer PT1 and current transformer CT1 on transmission line 1
, And the output voltage V2 of the voltage transformer PT2 on the side of the transmission line 2 on the secondary side of the system.
By switching the tap ratio of the load tap change transformer (LRT) 1d and turning on / off the switch SW1 or SW2,
Reactive power control is performed by connecting or disconnecting the corresponding power capacitor (SC) or shunt reactor (shR) to or from the system.

This control principle is based on a voltage / reactive power flow pattern determined based on a certain prediction, and the deviation from the actual is determined by using a transformer tap (LRT), a power capacitor (SC) for phase adjustment, and a shunt. The voltage and the reactive power are controlled by performing correction by adjusting the reactor (shR).

An example of the voltage / reactive power control will be described below. (1) When the voltage is high and the reactive power is large, a command to lower the tap of the LRT is issued from the command signal line s1 to lower the tap of the LRT. (2) When the voltage is high and the reactive power is small, a command to turn off SW2 is issued from the command signal line s3 to release the SC, or a command to turn on SW1 is issued from the command signal line s2 and shR is input. (3) When the voltage is low and the reactive power is small, a LRT tap-up command is issued from the command signal line s1 and the LRT is increased.
Raise tap. (4) When the voltage is low and the reactive power is large, an ON command for SW2 is issued from the command signal line s3, SC is turned on, or an OFF command for SW1 is issued from the command signal line s2,
Release shR.

Next, the system voltage controller 1a shown in FIG.
Will be described with reference to FIG. FIG. 2 shows an example of a functional block configuration of the system voltage control device 1a.

In FIG. 2, the system voltage control device 1a comprises:
The control unit 20 includes a control calculation unit 20 that performs a voltage / reactive power control calculation, and a sensitivity correction unit 30 that evaluates the state of the power system and corrects the sensitivity of the tap switching operation of the LRT 1d. These can be specifically realized by a computer system. Although not shown, the computer system includes a central processing unit, a memory, an external storage device, an input device, an output device, and the like. The external storage device is
For example, a fixed disk or a magneto-optical disk is used as a storage medium. The external storage device includes programs, data, membership functions,
Rules and the like are stored. The memory is loaded with necessary programs, data, and the like. The central processing unit realizes various functions by executing a program. Further, the control operation unit 20 and the sensitivity correction unit 30 may be realized by the same computer system or may be realized by different systems.

The control operation unit 20 includes a voltage V1 and a current I
Reactive power detector 21 for detecting reactive power by taking in 1
And target value setting unit 2 for setting target values Qo and Vref
2, an A / D converter 23 for A / D converting the voltage V2 to a digital amount Vrms, a deviation calculator 24 for calculating a deviation between the detected reactive power and the target value Qo, and a detected system. A deviation calculator 25 for calculating a deviation between the voltage Vrms and the target value Vref; a voltage / reactive power control calculator (VQ control calculator) 26 for integrating these deviations to perform a voltage / reactive power control calculation; According to the result, the phase adjustment operation (S
C, input and disconnection of shR) and LRT tap switching operation.

The control operation unit 20 operates as follows.
First, the target value setting unit 22 sets the target values Qo and Vref in advance. This target value is set as a digital value. On the other hand, the reactive power detector 21 detects the voltage V1 and the current of the transmission line 1 at a predetermined sampling cycle.
I1 is taken in, converted into a digital value, and the reactive power is calculated. Further, the A / D converter 23 takes in the voltage V2 of the transmission line 2 at a predetermined sampling cycle, A / D converts the voltage V2 into a digital amount Vrms, and outputs it.

The deviation calculator 24 takes in the detected reactive power and the target value Qo to determine a deviation, and calculates the deviation as V
Output to the Q control operation unit 26. The deviation calculator 25 takes in the detected system voltage Vrms and the target value Vref to obtain a deviation, and outputs the deviation to the VQ control calculator 26.
The VQ control calculator 26 performs a voltage control calculation and a reactive power control calculation based on the deviation. This calculation result is sent to the control sequence unit 27. The control sequence unit 27 performs the phase adjustment operation (SC, shR
Of the LRT 1d).

The sensitivity correction section 30 has a state evaluation section 31 for evaluating the state of the voltage of the power system, and a fuzzy inference execution section 32 for executing fuzzy inference according to the state evaluation. The fuzzy inference execution unit 32 includes a preset fuzzy control rule storage unit 321, a membership function storage unit 322 corresponding to a fuzzy label, and an inference unit 320. The inference unit 320 has an antecedent unit 323, a consequent unit 324, and a synthesis unit 325, executes fuzzy inference, and outputs the inference result kf as a sensitivity correction value. The actual fuzzy inference method will be described later.

The personalization operation support apparatus 1e shown in FIG. 1 has a user interface section 1c for inputting various instructions such as requests from an operator, displaying simulation results, and the like, and a simulation section 1b. Simulation unit 1
b adjusts a fuzzy rule and a membership function corresponding to a fuzzy label to satisfy the performance of individualization. That is, the simulation unit 1b includes, as will be described in detail later, a specification required by the operator, a signal Vrms obtained by quantizing a voltage V2 of the power system taken from the transmission line 2 into a digital value, and command signals s1, s2, and s3. And a target voltage Vref, and an optimal control simulation is performed to set the adjustment amount k1 of the membership function corresponding to the fuzzy rule and the fuzzy label, and transmit the adjustment amount k1 to the voltage / reactive power control device 1a. is there.

The individualization operation support apparatus 1e is constituted by a computer system, for example, as shown in FIG. In FIG. 13, the voltage adjustment relay 12h
An example is shown in which the voltage adjustment relay is replaced with the system voltage control device 1a. In FIG. 13, a simulation unit 1b includes a digital input / output interface 13a for taking in a system voltage and a tap elevating / lowering command and outputting an adjustment value, and an external storage for storing information using a magnetic disk and a recording medium for struggling with light. Device 13b and a central processing unit (C
PU) 131 and a computer body 13C having a memory 132. The user interface unit 1c includes a display 13d and a keyboard 13e.
Having.

Next, adjustment of membership functions corresponding to fuzzy rules and fuzzy labels used by the fuzzy inference executing unit 32 by the simulation unit 1b will be described with reference to FIGS.

The simulation section 1b calculates voltage data (non-control voltage data) of the system before tap switching is performed, and stores the calculated voltage data.
1 and an optimal control operation unit 42 that performs an optimal voltage control operation (simulation) according to the target voltage Vref and the user's required specifications shown in FIG. 4 using the non-control voltage data.
And an adjustment amount determining unit 43 that adjusts a membership function corresponding to a fuzzy control rule and a fuzzy label based on a simulation result and determines an adjustment amount.

The non-control data generator 41 takes in the effective voltage Vrms of the system and the LRT tap switching command, and generates and stores non-control voltage data indicating that if there is no tap switching, the voltage of the system will be like this. . The storage requires a huge amount of data, so the external storage device 13
Use b. The optimum control calculation unit 42 performs the optimum voltage control calculation in accordance with the target voltage Vref and the specification required by the user shown in FIG. Actually, the optimum control calculation unit 42 performs control (for example, determination of an optimum LRT tap switching time) according to a user request by performing an optimum control simulation. 14 and 15 show the procedure of the simulation of the optimal control operation unit 42. This procedure will be described later. The adjustment amount determination unit 43 determines a result of the simulation (for example, 30
The adjustment of the membership function corresponding to the fuzzy control rule and the fuzzy label is performed based on the error of the minute average voltage), and the adjustment amount is transmitted to the system voltage control device 1a.

The user's request is as shown in FIG.
Depending on the substation where the voltage control device is installed, it varies widely. For example, as shown in Case 1 in FIG. 4, "the location of the substation is a factory zone, and there are many loads affected by voltage fluctuations. , The peak value of the error of the instantaneous value with respect to the target voltage should be as small as possible, and as shown in Case 2, the substation is located in a suburban depopulated area and is affected by voltage fluctuations. Since there is almost no load, the error may be slightly large, but the number of switching of the LRT tap should be reduced as much as possible to extend the life. "

Next, the operation of the fuzzy inference executing unit will be described in detail with reference to FIGS. 5, 6 and 7. Here, ae in FIG. 5 indicate time zones.
FIG. 6 shows an example of a rule applied to each time zone. FIG. 7 shows an example of a membership function applied when the rule shown in FIG. 6 is executed.

(1) The rule for the time zone a shown in FIG. 5 is executed in the midnight time zone. In the late-night time zone, since there is generally no large load fluctuation, a rule is provided that focuses only on the magnitude of the error (V30) of the 30-minute average voltage, which is one of the evaluation items. That is, "If V30 is
If it is larger on the positive side or the negative side, the sensitivity coefficient Kf is made smaller (higher sensitivity). "" If V30 is small, the sensitivity coefficient Kf becomes large (low sensitivity). "By applying these rules, the former facilitates tap switching and improves the quality of the voltage.
Tap switching is difficult to perform, unnecessary tap switching is suppressed, and control is performed to extend the life of the LRT.

(2) The rule of time zone b shown in FIG. 5 is executed in the time zone in which the target voltage in the morning is changed (voltage increase). In this time zone, a load for startup during operation is applied, and the voltage drops rapidly, so that early tap switching is required. In this case, V30 and its gradient △ V
30 is provided. That is, "If,
If V30 is larger on the positive or negative side, the sensitivity coefficient Kf
Is smaller (higher sensitivity). "" If V30 is small, make the sensitivity coefficient medium. "By applying these rules, the former facilitates tap switching and improves the quality of the voltage, while the latter makes the sensitivity equal to the conventional one.

Also, "if ΔV30 is small or large on the positive side, the sensitivity coefficient is medium.""If ΔV30 is large on the negative side, the sensitivity coefficient is small (high sensitivity In the former, the sensitivity is set to the same level as in the past according to this rule. On the other hand, in the latter, since the voltage effective value changes in the direction opposite to the target voltage and the error increases, control is performed so as to increase sensitivity, facilitate tap switching, and improve voltage quality. That is, the control is performed by predicting the fluctuation of the load to some extent.

(3) The rule of the time zone c shown in FIG. 5 is executed in the time zone where the target voltage in the morning and afternoon is set higher. This time zone is the daytime working hours and is the time zone where the power demand is highest, so that one of the evaluation items, V
A rule focusing on only 30 is provided. That is, "if V30 is large on the positive side or negative side, sensitivity coefficient Kf is reduced (high sensitivity).""If V30 is small, sensitivity coefficient Kf is medium." By applying the above rule, the former facilitates tap switching and improves the voltage quality. On the other hand, the latter
The sensitivity is controlled to be equal to the conventional one. Also,
The control rule for this time zone does not increase the sensitivity coefficient even if the sensitivity coefficient decreases. This is intended to emphasize voltage quality.

(4) The rule for the time period d shown in FIG. 5 is executed during the lunch break time period. A general feature of the load fluctuation in this time zone is that the load fluctuation is very large within a short time (about one hour). Therefore, attention is paid to the magnitude V5 of the error of the average voltage for 5 minutes as well as the content of the rule of the time zone b. That is, "if V30 is large on the positive side or negative side, sensitivity coefficient Kf is reduced (high sensitivity).""If V30 is small, sensitivity coefficient is medium." By applying the rule, the former facilitates tap switching, and improves the quality of voltage. On the other hand, in the latter case, the sensitivity is controlled so as to be equal to the conventional one.

"If V5 is large on the positive side or the negative side, the sensitivity coefficient Kf is reduced (high sensitivity).""If V5 is small, the sensitivity coefficient is made medium. "By applying these rules,
The former facilitates tap switching and improves voltage quality. On the other hand, in the latter case, the sensitivity is controlled so as to be equal to the conventional one.

(5) The rule of the time zone e shown in FIG. 5 is executed from the evening to the night. In this time zone, the load is gradually cut off, the load becomes lighter, and the voltage becomes higher. Therefore, a rule focusing on V30 is provided. That is,
"If V30 is larger on the positive or negative side, the sensitivity coefficient Kf is made smaller (higher sensitivity)."
Is small, the sensitivity coefficient Kf is set to a medium value. "
By applying these rules, the former facilitates tap switching and improves voltage quality. On the other hand, in the latter case, the sensitivity is controlled so as to be equal to the conventional one.

As described above, by switching and executing the rule group according to the target voltage and the load variation, more effective voltage control can be performed, and the rule group itself can be simplified, so that the amount of arithmetic processing is reduced. it can.

Next, a method of determining a sensitivity coefficient by fuzzy inference will be described with reference to FIG. Fuzzy theory is a theory based on fuzzy set theory that deals with ambiguity caused by human subjectivity. Note that a fuzzy set is a set of elements whose boundaries are ambiguous and the degree of belonging to the set is represented by a membership function. This membership function takes a value from 0 to 1 and calls the value a degree (grade; fitness) belonging to the set. The expression was blurred by associating this grade with the degree of ambiguity (when 1 is completely applicable, when 0 is not completely applicable, between 0 and 1 is applicable according to the value). Expression becomes possible.

As described above, a major feature of the fuzzy theory is that ambiguity of words is quantified by a membership function. As a result, knowledge such as intuition and experience of human beings can be handled in a manner that is easy to understand, and comprehensive judgment by leveling according to the situation of many knowledge and analogical judgment using information on deviation from knowledge can be performed It is.

The membership function and inference execution example of the antecedent part and the consequent part shown in FIG. 7 are examples of rule execution in the time period c shown in FIG. That is, "If V30 is large on the positive side, the sensitivity coefficient Kf decreases (increases sensitivity).""If V30 increases on the negative side, sensitivity coefficient Kf decreases (increases sensitivity). "If V30 is small, the sensitivity coefficient is medium." First, the degree of conformity to each individual control rule is determined. In general, max-min
Method.

Next, the fitness of the consequent part of each rule is synthesized, and a weighted average value shown by the following equation is obtained (defuzzification).
Thus, the sensitivity coefficient Kf is determined.

Kf = (Σgi · zi) / Σgi (1) gi: the conformity of the rule zi: the center of gravity of the rule In order to determine the membership function corresponding to the fuzzy label described above. At present, humans evaluate and evaluate evaluation index values (such as the magnitude of the error of the 30-minute average voltage). Therefore, it is necessary to evaluate and determine the evaluation index value while changing the form of the membership function.
The decision takes a great deal of time.

Here, the optimum control operation unit 42b shown in FIG.
Will be described in detail with reference to FIG. 8, FIG. 9 and FIG.

FIG. 8 is a diagram for explaining an operation for minimizing the peak value of the 30-minute average voltage error by switching the number of times set by the user as an example of the optimal control. These are summarized below.

(A) Uncontrolled voltage data (for one day [0:
00 to 24:00]) and input 30 to the target voltage.
The peak value of the error of the minute average voltage is detected, and the time is detected. (B) A zero-cross point that is before the time of the peak value detected in (a) and that is closest to the peak value is detected, and the time is detected. This time is determined as the optimum time for tap switching. (C) The processing shown in (a) is performed again from 0:00,
At this time, when the time detected in the processing shown in (b) has come, a tap switching operation is performed. Therefore, the system voltage at this time can be said to be a voltage resulting from performing the tap switching operation once at an optimal time in order to minimize the peak value of the error of the 30-minute average voltage. (D) The processes shown in the above (a) to (c) are repeatedly executed for the number of switching times set by the user.

FIG. 9 shows another example of the optimal control in which the number of times set by the user is switched to minimize the accumulation of errors in the 30-minute average voltage in one day (that is, the area of the errors). FIG. These are summarized below.

(A ′) Uncontrolled voltage data (1 day [0:00 to 24:00]) is input, and the area of each area from the zero-cross point to the zero-cross point of the 30-minute average voltage error with respect to the target voltage is input. Find the maximum point.

(B ') The zero cross point of the area detected in (a') is detected, and the time is detected. This time is determined as the optimum time for tap switching.

(C ') The processing shown in (a') is performed again from 0:00. At this time, if the time detected in the processing shown in (b ') comes, the tap switching operation is performed. I do. Therefore, the system voltage at this time can be said to be a voltage resulting from performing the tap switching operation once at an optimal time in order to minimize the area value of the error of the 30-minute average voltage.

(D ') The processing shown in the above (a') to (c ') is repeatedly executed for the number of switching times set by the user.

FIG. 10 shows an example of the result of switching the number of times set by the user shown in FIG. 8 and controlling the peak value of the error of the average voltage for 30 minutes to the minimum. FIG. 10A shows the effective voltage value, and FIG. 10B shows the error of the 30-minute average voltage. FIG. 10 also shows a tap switching command indicating a point in time when the tap switching operation is performed.

Next, the adjustment amount determining section 43 shown in FIG. 3 will be described with reference to FIG.

FIG. 11A shows the error of the 30-minute average voltage with respect to the target voltage of the voltage optimally controlled in accordance with the user's request in the optimal control operation unit 43 shown in FIG.
Here, first of all, during the rule's effective time,
The peak value ε of the error of the average voltage for 30 minutes is detected. This ε
Corresponds to the adjustment amount K1.

Next, the fuzzy labels (NB, ZO, and NB) in the magnitude of the error of the 30-minute average voltage shown in FIG.
The positions of the inflection points x1, x2, x3, and x4 of the membership function of PB) are changed on both the positive side and the negative side according to the detected error peak value ε, and the inflection points x1 ′, x
They are set at the positions 2 ', x3' and x4 '. That is, when the peak value of the error is large (low sensitivity),
When the slope of the membership function shown in FIG. 11B is small and the peak value of the error is small (high sensitivity)
Can optimize the membership function such that the slope of the membership function shown in FIG.

The above description is for a request to reduce the peak value of the 30-minute average voltage error. Similarly, the peak value of the 5-minute average voltage error and the 30-minute average voltage error are similarly described. It goes without saying that the present invention can be applied to a request for reducing the area of the error.

Next, another embodiment of the present invention will be described. This embodiment is an example in which the present invention is applied to a voltage adjustment relay (voltage adjustment relay).

FIG. 12 shows a block configuration when the present invention is applied to a voltage adjusting relay (voltage adjusting relay).

In FIG. 12, the voltage adjusting relay according to the present embodiment includes a voltage transformer 12a, an execution value detecting unit 12b for detecting an effective value Vrms of the system voltage from the output voltage of the voltage transformer 12a, A target voltage setting unit 12f for setting the voltage Vref, and an addition unit 12c for calculating a deviation dV between the target voltage Vref set by the target voltage setting unit 12f and the effective value Vrms of the system voltage detected by the execution value detection unit 12b. A deviation integrator 12d that constantly integrates the deviation dV for a predetermined period of time, a switching determining unit 12e that performs tap switching switching determination, a setting unit 12g that sets a set value K, and switching of tap switching by the determining unit 12e. A sensitivity correction unit 30 for calculating a sensitivity coefficient Kf for performing the determination. The voltage adjustment relay 12h is, for example, excluding the voltage transformer 12a and some other elements,
It can be configured by a computer system using a microcomputer or the like.

The execution value detection unit 12b includes a voltage transformer 12a
Has a function of converting the output voltage of the above to a digital value. The switching determination unit 12e includes an output signal of the deviation integration unit 12d and an output signal Kf of the sensitivity correction unit (sensitivity coefficient calculation unit) 30.
The switching determination of tap switching is performed by comparing the magnitude with a value K · Kf multiplied by a setting value K set by the setting unit 12g. The sensitivity correction unit 30 has the same configuration as that shown in FIG. 2, takes in the state quantity of the power system shown in FIG. The sensitivity coefficient Kf for performing the switching determination of is calculated.

The voltage adjusting relay 12h of this embodiment controls tap switching of the tap switching transformer 12i. The load 12j is connected to the tap switching transformer 12i via the distribution line 12.

Further, the individualization operation support device 1e is connected to the voltage adjustment relay 12h. As described above, by adding the individualization operation support device 1e to the voltage adjustment relay 12h, voltage adjustment (voltage control) suited to the individuality of the operator is performed.
It can be performed.

That is, since the voltage adjustment relay 12h is installed at the substation closest to the load (demand side) as a substation, the number of installed voltage adjustment relays is extremely large, and the operation thereof is individually entrusted to the operator. I have. Therefore, according to the present embodiment, the membership function corresponding to the fuzzy rule and the fuzzy label can be easily adjusted, so that the operator can also save labor.

FIG. 13 shows an example of the hardware configuration of the individualization operation support apparatus 1e used in this embodiment. This hardware configuration is common to that used in the embodiment shown in FIG. 1 and has already been described, and will not be repeated here.

Next, the operation of the individualized operation support apparatus shown in FIG. 13 will be described with reference to the flowchart shown in FIG. This operation can be similarly applied to the individualized operation support device in the embodiment shown in FIG. 1, except that the target is the system voltage control device.

In FIG. 14, first, at step 14a
Then, an initial process for clearing the memory 132 and the like of the computer main body 13 is performed. Next, in step 14b, the system voltage data and LR are input from the digital input / output unit 13a.
Capture a T tap operation command signal. The sampling cycle of the input data at that time is the same as the voltage adjustment relay 12h in FIG.
Is set to 100 ms, which is the same as the calculation cycle of. Thereafter, in step 14c, non-control voltage data when no LRT tap operation is performed is created, and the data is stored in the external storage device 13b. Since the external storage device 13b needs to store an extremely large amount of data, a device having a large storage capacity such as a fixed disk device or a magneto-optical disk device is used. In step 14d, it is determined whether or not data necessary for the optimal control simulation has been prepared. When the data is completed, the process proceeds to a process for performing an optimal control simulation. If the data is not available, the process returns to the data input block and performs data input.

The time for collecting the data is, for example, about one to two weeks so that data on weekdays and holidays can be sufficiently collected.

Next, the process proceeds to the optimal control simulation based on the collected data. First, step 14
At e, the specification required by the input operator from the keyboard 13e is accepted. As described above, this required specification is operated, for example, as follows: "The peak value of the error of the 30-minute average voltage is set to 1.0% or less, and the number of times of tap switching is set to about 30 times." Set according to the individual's personality. next,
In step 14f, non-control data is read from the external storage device 13b, and in step 14g, an optimal control simulation is performed so as to meet the above-mentioned requirement. Step 14
At h, it is determined whether the optimal control simulation has been completed the required number of times. If not, repeat step 14
The processing from f is executed until the optimal control simulation ends. When the processing is completed, the data is displayed on the display 13d in a step 14i.

Next, in step 14j, the adjustment amount K1 of the membership function corresponding to the fuzzy rule and the fuzzy label is calculated. The adjustment amount K1 is obtained, for example, by detecting the maximum value of the 30-minute moving average value of the error with respect to the target voltage when the above-described optimal control simulation ends. In step 14k, the adjustment value is transmitted to the voltage adjustment relay 12h and set. The voltage adjustment relay 12h is used by storing the adjustment value in a nonvolatile memory (EEPROM) or the like in which the adjustment value is incorporated. The adjustment of the membership function by the adjustment amount K1 can be performed, for example, as shown in FIG.

Here, the algorithm of the optimal control simulation in step 14g will be described in detail with reference to FIG.

The setting of the number of tap changes per day is received from the keyboard 13e (step 1501).
The contents of the memory 132 and the counter (not shown) are initialized (step 1502).
The ideal switching time of the transformer tap, which is obtained every time it is repeated every day, is not initialized. The non-control voltage data when there is no tap switching stored in the external storage device 13b is read (step 1503).

Here, it is determined whether or not the time of the read data matches the tap switching time (step 1).
504). Note that the tap switching time here is obtained in step 1511 described below.
If the determination result is a match, the voltage for one tap is added to or subtracted from the read no-control voltage data (step 1505).

Next, if the time of the read data does not coincide with the tap switching time, or
When the calculation of step 5 is completed, an error with respect to the target voltage is obtained (step 1506). A 30-minute moving average of the error is obtained (step 1507). A zero crossing point at which the 30-minute moving average of the obtained error changes from the positive side or the negative side to the negative side or the positive side is obtained, and the data of the time indicating the point is stored in the memory 1.
32 (step 1508). Then, it is determined whether data for one day has been read (step 150).
9). If the data for one day has not been read, the processing from step 1503 is repeated until the data has been read.

After reading the data for one day, 3
The maximum value of the 0-minute moving average is detected, and the time is obtained (step 1510). Then, the time of the zero cross point closest to the time before the time obtained in step 1510 is obtained (step 1511). In other words, the time of this zero cross point is an ideal tap switching time, and is a time when an operation for switching the maximum value of the 30-minute moving average voltage of the error in a direction approaching zero is performed. Here, it is determined whether or not the number of times of tap switching has reached the set value (step 1512). If the number of switching has reached the set value,
If the processing has been completed and the count has not been reached, the processing from step 1502 is repeated until the switching count reaches the set value.

In this way, the individualization operation support device is installed adjacent to the voltage adjustment relay installed in the substation,
Can be operated online. Alternatively, only the data may be collected, an optimal control simulation may be performed on the data off-line, and the execution result may be directly set by the operator in the voltage adjustment relay.

Further, if the computer in the voltage adjustment relay has a sufficient processing capability, it is needless to say that the optimal control simulation can be executed in the voltage adjustment relay and the operator can be personalized.

Next, based on the simulation result,
FIG. 1 shows another embodiment for changing the membership function.
This will be described with reference to FIG.

First, 3 based on the optimal simulation results
The maximum value ε of the 0-minute average voltage error is detected, and the adjustment amount a is
It is calculated according to the following equation.

A = (maximum value of error ε) / α (2) where α is a normalization constant. Adjust the membership function in the consequent.

Membership function after adjustment = membership function before adjustment * a (3) In this example, the consequent part is a membership function of a singleton format. That is, in this example, the value of the membership function is adjusted.

As described above, the sensitivity coefficient Kf is obtained by combining the membership functions of the respective consequent parts, performing weighted averaging processing and defuzzifying as shown in equation (1). .

As described above, the effect of adjusting the membership function of the consequent part is the same as the effect of adjusting the membership function of the antecedent part described above. However, the method of adjusting the membership function of the consequent has an additional effect that the operation can be simplified.

In the above embodiment, the system voltage controller (VQ
Control device) and an example of performing LRT tap control of the voltage adjustment relay have been described, but the present invention is not limited to this. The present invention is characterized by providing a simulation means for optimizing an operator's request and a means for adjusting a membership function for a fuzzy label based on a result of the simulation. It is also applicable to the device. For example, the present invention is also applicable to reactive power control using SC and shR in a VQ control device. The reactive power control is described in, for example, Electric Cooperative Research Vol. 47, No. 1 (July 1991).

[0099]

As described above, according to the present invention,
Optimal voltage control according to the operation style of the user (operator) who operates the power system can be performed, and more flexible and individual operation can be performed.

Further, it is not necessary to determine the membership function corresponding to the fuzzy rule or the fuzzy label by trial and error, and the membership function corresponding to the fuzzy rule or the fuzzy label can be easily set in a short time.

Further, even when the power system is operated, the performance of the voltage control device can be easily changed, and a user-friendly voltage control system can be constructed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a substation including a system voltage control device that performs system voltage control using an individualization operation support device of the present invention.

FIG. 2 is a block diagram illustrating an example of a configuration of a system voltage control device (voltage / reactive power control device) used in the embodiment.

FIG. 3 is a block diagram showing a functional configuration of a simulation unit of the individualization operation support device used in the embodiment.

FIG. 4 is an explanatory diagram showing an example of a specification required by an operator.

FIG. 5 is an explanatory diagram showing a relationship between a target voltage of the voltage / reactive power control device and a time zone to which fuzzy inference is applied.

FIG. 6 is an explanatory diagram showing one embodiment of a fuzzy rule used in fuzzy inference performed in the system voltage control device.

FIG. 7 is an explanatory diagram showing a method of determining a sensitivity coefficient by fuzzy inference.

FIGS. 8A and 8B are explanatory diagrams for explaining a method for determining an optimum LRT tap switching position according to the present invention, wherein FIG. 8A is a waveform diagram showing a state in which the switching position is obtained, and FIG. It is a waveform diagram which shows the state which calculates the tap switching process in the position calculated | required in (A).

FIG. 9 is an explanatory diagram for explaining another method for determining an optimum LRT tap switching position according to the present invention;
FIG. 7B is a waveform diagram showing a state in which a switching position is obtained, and FIG. 7B is a waveform diagram showing a state in which recalculation is performed and a tap switching process is calculated at the position obtained in the above (A).

FIG. 10 is a waveform chart showing an example of an error between a voltage effective value and a 30-minute average voltage according to the present invention, wherein (a) shows a voltage execution value and (b) shows an error%.

FIG. 11 is an explanatory diagram showing one method of adjusting a membership function corresponding to a fuzzy label according to the present invention.

FIG. 12 is a block diagram showing an example of a configuration of an example in which the present invention is applied to a voltage adjustment relay that performs system voltage control using the individualization operation support device of the present invention.

FIG. 13 is a diagram showing an example of hardware of the individualization operation support device of the present invention.

FIG. 14 is a flowchart illustrating an example of a processing procedure of the individualization operation support device of the present invention.

FIG. 15 is a flowchart showing an algorithm of an optimal simulation performed in the present invention.

FIG. 16 is an explanatory diagram showing another method of adjusting a membership function corresponding to a fuzzy label according to the present invention.

Continuation of the front page (56) References JP-A-3-230723 (JP, A) JP-A-4-275026 (JP, A) JP-A-52-5438 (JP, A) JP-A-4-251525 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02J 3/00-5/00

Claims (6)

(57) [Claims] 1. A substation having a load tap change transformer, a voltage control device for controlling tap change operation of a load tap change transformer to maintain a system voltage at a predetermined voltage, An operation support device for supporting the operation of the voltage control device while satisfying individual requirements, the voltage control device comprising: a load tap switching transformer based on a state of a power system. A control operation unit for performing a voltage control operation for determining the tap switching operation of the control system, and an evaluation amount of the state of the power system, and a fuzzy inference using a membership function corresponding to the evaluation amount, the control operation unit A sensitivity correction unit for determining the amount of sensitivity correction for determining the tap switching operation and sending the sensitivity correction amount to the control calculation unit. Request input means for receiving an input and an optimal control simulation for optimally determining a tap switching operation in accordance with a preset target voltage and a request from an operator with respect to accumulated system voltage data. A control operation unit,
A substation comprising: an adjustment amount determining unit that obtains an adjustment amount for adjusting the membership function from a simulation result. 2. A voltage control device for controlling a tap change operation of a load tap change transformer to maintain a system voltage at a predetermined voltage in a substation provided with a load change tap change transformer. An operation support device for supporting the operation of the voltage control device while satisfying individual requirements.The voltage control device is configured to perform on-load tap switching transformer based on the state of the power system. A control operation unit for performing a voltage control operation for determining a tap switching operation of the heater, and an evaluation amount of a state of a power system, and the control operation unit is determined by fuzzy inference using a membership function corresponding to the evaluation amount. And a sensitivity correction unit for determining the amount of sensitivity correction for the determination of the tap switching operation in step (a) and sending the sensitivity correction amount to the control operation unit. Request control means for receiving a request, and for the accumulated system voltage data, perform an optimal control simulation for optimally determining a tap switching operation in accordance with a preset target voltage and a request from an operator. An optimal control operation unit,
A voltage control device comprising: an adjustment amount determining unit that obtains an adjustment amount for adjusting the membership function from a simulation result. 3. A sensitivity obtained by a fuzzy inference using a membership function for a tap switching operation for maintaining a system voltage at a predetermined voltage with respect to a load tap switching transformer installed in a substation. An operation support device that supports the operation of a voltage control device that is determined based on the state of the power system with the sensitivity specified by the correction amount, and accepts requests from operators operating substations. Request input means, means for creating and accumulating system voltage data before the current tap switching operation is performed, and, for the accumulated system voltage data, a preset target voltage and a request from the operator. In addition, an optimal control operation unit that performs an optimal control simulation for optimally determining a tap switching operation, and adjusts the membership function from a simulation result. An operation support apparatus, comprising: an adjustment amount determining unit that obtains an adjustment amount for adjustment; and configuring them with a computer. 4. An on-load tap change transformer installed in a substation.
Maintain system voltage at a pre-designated voltage
Tap switching operation using a membership function.
Specified by the sensitivity correction amount obtained by fuzzy inference
And make decisions based on the state of the power system.
When performing control to maintain the voltage at the specified voltage
Requests from the operators of the substations
Target voltage set in advance for the voltage data of the
According to the a request from the operator and, determine the tap switching operation
Perform optimal control simulations to perform optimal
From the simulation results, the above membership function
Determining an adjustment amount for adjusting the power
System operation support method. 5. The method according to claim 4, wherein the request is from an operator.
For the time required to be accepted
Tolerance of target voltage for average voltage and number of tap switching
How to support the operation of a power system that includes at least
Law. 6. The stored system voltage according to claim 5,
Data is stored in the grid power before the tap change operation is performed.
Voltage data that is created and stored
Operation support method.