JPH10201103A - Voltage reactive power controller for power system - Google Patents

Abstract

(57) [Problem] To provide a voltage reactive power control device capable of performing responsive voltage control without being affected by fluctuations in power demand. SOLUTION: A voltage maintenance calculation means 7 is started in a predetermined control cycle, and calculates a control amount to each control device based on a deviation between a bus voltage of a power system and a reference voltage set in a reference voltage setting means 8. calculate. Then, the control speed correction means 9 calculates the change speed of the load change of the power system as the system change speed, and changes the control cycle of the voltage maintenance calculation means 7 according to the calculated system change speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage reactive power control device which controls the voltage of a power system by adjusting reactive power.

[0002]

2. Description of the Related Art Generally, in a power system, a voltage at a predetermined monitoring point in the power system is maintained constant in order to stably supply high-quality power. The voltage adjustment in this case is performed by adjusting the reactive power.

FIG. 10 is a block diagram showing a case where such a voltage reactive power control device (VQC) is employed in a power system. The voltage reactive power control device 1 includes an electronic computer 2. That is, the computer 2 has a built-in VQC program for voltage reactive power control, and the voltage reactive power control device 1 is formed by executing and processing the VQC program in the computer 2.

[0004] A power system (PWN) 3 is provided with a control device 4 having a generator and a phase adjustment facility capable of adjusting the system voltage, and serves as a target when maintaining and controlling the bus voltage to the reference voltage. A monitoring point 5 is provided. Here, since a plurality of control devices 4 are provided, the control devices 4 are hereinafter expressed as control devices j (j = 1, 2,...)
Are also provided with a plurality of monitoring points, and are hereinafter expressed as monitoring points i (i = 1, 2,...).

[0005] The bus voltage Vi at the monitoring point i of the power system network 3 and the reactive power Qj adjusted by the control device j are supplied to the voltage reactive power control unit 1 of the voltage reactive power control device 1 via a cyclic digital telemeter (CDT) 6. 7 is input. The voltage maintenance calculation means 7 calculates the bus voltage based on the deviation between the bus voltage target value Vrefi which is the reference voltage of the bus set by the reference voltage setting means 8 of the voltage reactive power control device 1 and the bus voltage Vi at the monitoring point i. The voltage Vi is set to the bus voltage target value V
Command value Q to control device j required to maintain refi
Dj is created, and the command value QDj is output to the control device j via the cyclic digital telemeter 6.

Incidentally, the voltage reactive power control device 1 determines that the bus voltage Vi at the monitoring point i of the power grid 3 is equal to the bus voltage target value V
If refi deviates from the allowable value εi,
The value of the evaluation function E as shown in the following equation (2) is obtained, and the reactive power control amount of the control device j that reduces the value of the evaluation function E (hereinafter, referred to as the control amount Xj of the control device j). By outputting a command value based on the control amount Xj (the command value is the sum of the current reactive power Qj of the control device j and the control amount Xj) to the local control device j, the bus voltage Vi at the monitoring point i is obtained.
Is controlled within an allowable range.

FFi = | Vi−Vrefi | −εi (1)

[0008]

(Equation 1)

However, in the equation (1), | Vi−Vrefi | ≪
When εi, FFi = 0. Also, Vi is the bus voltage at the monitoring point i, Vrefi is the bus voltage target value at the monitoring point i, εi
Is the allowable value of the monitoring point i, and n is the number of monitoring points.

FIG. 11 is a flow chart showing the operation of the voltage maintenance calculation means 8. First, step S1
Then, the value of the evaluation function E in the initial state where no control is performed is calculated. The method of calculating the evaluation function E is based on the above equation (2).

Next, in step S2, the order of the control effects in the control device j is determined. That is, ∂E / ∂Xj obtained by differentiating the equation (2) by the control amount Xj is obtained by the following equation (3).

[0012]

(Equation 2)

Here, Aij is a sensitivity constant (∂Vi / ∂Xj) representing a change amount of the bus voltage Vi at the monitoring point i with respect to the control change amount of the control device j. Also, | ∂E / ∂Xj |
Has the following meaning: (A) The control device j having a large | ∂E / ∂Xj | is a control device having a large control effect in reducing the value of the evaluation function E. (B) The control device j with a small | ∂E / ∂Xj | is a control device with a small control effect in reducing the value of the evaluation function E. (C) The control device with | ∂E / ∂Xj | = 0 evaluates the evaluation function E
Is a control device that has no control effect in reducing the value of.

In accordance with the above relationship, in step S2, the order of the control devices j is determined in descending order of the control effect. That is, the order of the control devices j is determined in descending order of the value of | ∂E / ∂Xj |.

Next, in step 3, the control amount is increased (or decreased) by one unit operation amount ΔXj for the control device j having the greatest control effect obtained in step S2. That is, the control amount is updated as in the following equation (4).

[0016]

(Equation 3)

Next, at step S4, the control device j
The value of the evaluation function E based on one unit operation amount Δ × j is updated according to the following equations (5) and (6).

[0018]

(Equation 4)

However, when FFi≪Δij · ΔXj,
FFi = 0.

Next, in step S5, step S5
4. Compare the value of the evaluation function E updated in step 4 with the value before the update,
When the updated value increases, the control amount Xj of the control device j and the value of the evaluation function E after the update are returned to the original values in step S6, the control device j having the next effect is selected in step S7, and the step is performed again. Steps S3 to S5 are repeated.

If the value of the evaluation function E has decreased, it is determined in step S8 whether the number of repetitions has been exceeded. If not, the updated value of the evaluation function E and the monitoring point i
Based on the value of the voltage deviation, the process returns to step S2 again to calculate the control amount Xj. If the number of repetitions is over in step S8, the process moves to step S9. And each control device j
Is determined in step S9, a command value is obtained by the following equation (7).

QDj = Qj + Xj (7) where Qj is the current reactive power of the control device, QDj is the command value of the control device j, and Xj is the control amount of the control device j.

As described above, the voltage maintenance calculation means 7 obtains the command value to the control device j and performs the voltage reactive power control.

[0024]

However, in such a conventional apparatus, the control amount is calculated based on the calculated control amount in the morning hours when the load change rate is severe, or when the work starts immediately after lunch break when the load rises all at once. Even when the equipment was controlled, a voltage drop caused by a sudden increase in the load could affect the voltage value in an allowable range in some cases. For this reason, since voltage control is delayed, there is a problem such as erroneous control in the case of a device that performs control based on a voltage value.

It is an object of the present invention to provide a voltage reactive power control device capable of performing responsive voltage control without being affected by the magnitude of fluctuations in power demand.

[0026]

According to a first aspect of the present invention, there is provided a reference voltage setting means for setting a reference voltage of a bus of a power system, and a bus voltage and a reference voltage setting of the power system which are started at a predetermined control cycle. Voltage maintenance calculating means for calculating a control amount for each control device based on a deviation from a reference voltage set in the means, and a change rate of a load change of the power system is calculated as a change rate of the system, and the calculated change of the system is calculated. Control speed correction means for changing the control cycle of the voltage maintenance calculation means based on the speed.

According to the first aspect of the present invention, the voltage maintenance calculation means is started at a predetermined control cycle, and is supplied to each control device based on a deviation between the bus voltage of the power system and the reference voltage set in the reference voltage setting means. Is calculated. Then, the control speed correction means calculates the change speed of the load change of the power system as the system change speed, and changes the control cycle of the voltage maintenance calculation means according to the calculated system change speed.

According to a second aspect of the present invention, there is provided a reference voltage setting means for setting a reference voltage of a power system bus, and a reference voltage set in the power system bus voltage and the reference voltage setting means which is started at a predetermined control cycle. Voltage maintenance calculating means for calculating a control amount for each control device based on a deviation from voltage; and a control amount based on the calculated system change speed, calculating a change speed of a load change of the power system as a system change speed. And a control amount correcting means for calculating the correction coefficient of the above and correcting the control amount calculated by the voltage maintenance calculating means.

According to the second aspect of the present invention, the voltage maintenance calculating means is started at a predetermined control cycle, and sends to each control device based on a deviation between the bus voltage of the power system and the reference voltage set in the reference voltage setting means. Is calculated. The control amount correction means calculates the change speed of the load change of the power system as the system change speed, calculates a correction coefficient of the control amount based on the calculated system change speed, and calculates the control amount calculated by the voltage maintenance calculation means. Make corrections to

According to a third aspect of the present invention, there is provided a reference voltage setting means for setting a reference voltage of a power system bus, and a reference voltage set in the power system bus voltage and the reference voltage setting means which is started at a predetermined control cycle. Voltage maintenance calculating means for calculating a control amount for each control device based on a deviation from the voltage; and a voltage maintenance rate based on the calculated system variation rate, calculating a rate of change in load variation of the power system as a system variation rate. Control speed correction means for changing the control cycle of the calculation means, and a voltage maintenance calculation means for calculating a change rate of a load change of the power system as a system change speed, calculating a correction coefficient of a control amount based on the calculated system change speed, and voltage maintaining calculation means And a control amount correction means for correcting the control amount calculated in step (1).

According to the third aspect of the present invention, the voltage maintenance calculating means is started at a predetermined control cycle, and sends to each control device based on a deviation between the bus voltage of the power system and the reference voltage set in the reference voltage setting means. Is calculated. Then, the control speed correction means calculates the change speed of the load change of the power system as the system change speed, and changes the control cycle of the voltage maintenance calculation means based on the calculated system change speed. The control amount correction means calculates a change speed of the load change of the power system as a system change speed, calculates a correction coefficient of the control amount based on the calculated system change speed, and calculates the control amount calculated by the voltage maintenance calculation means. Make corrections to

According to a fourth aspect of the present invention, in the third aspect of the present invention, control data storage means for storing a control cycle and a control amount correction coefficient when the control result of the power system is good is additionally provided. When the control cycle at the same system change speed as the calculated system change speed is stored in the control data storage unit, the speed correction unit selects the control period. When the control amount correction coefficient at the same system change speed as the change speed is stored in the control data storage means, the control amount correction coefficient is selected.

According to a fourth aspect of the present invention, in addition to the operation of the third aspect of the invention, the control speed correction means stores the control cycle at the same system change speed as the calculated system change speed in the control data storage means. Select the control cycle when
If not, the control cycle is calculated based on the system change speed. Also, the control amount correction means selects the control amount correction coefficient when the control amount correction coefficient at the same system change speed as the calculated system change speed is stored in the control data storage unit, and when the control amount correction coefficient is not stored, Calculates the control amount correction coefficient based on the system change speed.

[0034]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing a first embodiment of the present invention. In the first embodiment, the change rate of the load change of the power system is calculated as a system change speed with respect to the conventional example shown in FIG. 11, and the control of the voltage maintenance calculating means 7 is performed based on the calculated system change speed. The control speed correcting means 9 for changing the cycle is additionally provided. The other configuration is the same as that of the conventional example shown in FIG. 11, and therefore, the same components are denoted by the same reference characters and description thereof is omitted.

FIG. 2 is a block diagram showing the calculation contents of the control speed correcting means 9. First, the control speed correction means 9
, Total demand forecast data 11 which is a total power demand forecast value for one day is set in advance by the total demand forecast setting means 10.
Then, the control speed correction means 9 calculates the change speed of the load change of the power system as the system change speed 12 based on the total demand forecast data 11 (S11), and calculates the voltage maintenance calculation means based on the calculated system change speed 12. 7 is determined (S12). The control cycle 13 determined by the control speed correction means 9 is input to the voltage maintenance calculation means 7, and the voltage maintenance calculation means 7 executes the voltage maintenance calculation in the control cycle 13 and calculates the command value QDj of the control device j. And outputs it to the control device j.

Next, FIG. 3 is an explanatory diagram of a method of determining the control cycle in the control speed correcting means 9. First, the load change amount of the total demand forecast data 11 every 30 minutes is checked, and the system change speed 12 which is the change speed of the load change of the power system is calculated. This system change speed 12 is represented as an expected total demand change amount. Next, this system change speed 12 (expected total demand change amount)
The control cycle is set based on. This control cycle is set in advance by setting a control cycle for a certain basic system change speed, and calculating and setting the control period based on the inverse ratio of the basic system change speed and the system change speed at that time. I do. Alternatively, a control cycle may be designated in advance for each range of the system change speed, and the control cycle may be selected and set. In any case, the control cycle is set to be short when the system change speed is high.

According to the first embodiment, when the load change is abrupt, the control cycle is advanced to execute the voltage maintenance calculating means 7, so that the voltage control with good responsiveness according to the system change speed is performed. It can be carried out.

Next, a second embodiment of the present invention will be described. FIG. 4 is a block diagram showing a second embodiment of the present invention. This second embodiment is similar to the first embodiment shown in FIG.
Instead of the control speed correcting means 9 of the embodiment, the change speed of the load change of the power system is calculated as the system change speed, and the correction coefficient of the control amount is calculated based on the calculated system change speed to calculate the voltage maintenance calculation. A control amount correcting means 14 for correcting the control amount calculated by the means 7 is provided. Other configurations are the same as those of the first embodiment shown in FIG. 1, and therefore, the same components are denoted by the same reference symbols and description thereof will be omitted.

FIG. 5 is a block diagram showing the calculation contents of the control amount correction means 14. First, the control amount correction means 14
, Total demand forecast data 11 which is a total power demand forecast value for one day is set in advance by the total demand forecast setting means 10.
Then, the control amount correction means 14 calculates the change speed of the load change of the power system as the system change speed 12 based on the total demand forecast data 11 (S21), and calculates the voltage maintenance calculation means based on the calculated system change speed 12. 7 control amount correction coefficient 15
Is determined (S22). The control amount correction coefficient 15 determined by the control amount correction unit 14 is input to the voltage maintenance calculation unit 7, and the voltage maintenance calculation unit 7 corrects the control amount by the control amount correction coefficient 15, and issues a command to the control device j. The value QDj is calculated and output to the control device j.

FIG. 6 is an explanatory diagram of a method of determining the control amount correction coefficient in the control amount correction means 14. First, the load change amount of the total demand forecast data 11 every 30 minutes is checked, and the system change speed 12 which is the change speed of the load change of the power system is calculated. This system change speed 12 is represented as an expected total demand change amount. Next, a control amount correction coefficient 15 is set based on the system change speed 12. A method of setting the control amount correction coefficient 15 is to set a control amount correction coefficient for a certain basic system change speed, and to control the control amount by the ratio of the basic system change speed to the system change speed at that time. Calculate and set the correction coefficient. Alternatively, each control amount correction coefficient is designated in advance for each range of the system change speed, and is selected and set. In any case, the control amount correction coefficient is set to be large when the system change speed is high.

According to the second embodiment, when the load change is abrupt, the control amount correction coefficient is increased and the voltage maintenance calculation means 7 calculates the control amount. Good voltage control can be performed.

Next, a third embodiment of the present invention will be described. FIG. 7 is a block diagram showing a third embodiment of the present invention. This third embodiment is different from the conventional example shown in FIG. 11 in that the control speed correction unit 9 in the first embodiment and the control amount correction unit 1 in the second embodiment are different from each other.
4 is added. That is, the control amount correction means 1 of the second embodiment is different from the first embodiment shown in FIG.
4 is additionally provided.

Thus, the control speed correction means 9 calculates the change speed of the load change of the power system as the system change speed, and changes the control cycle of the voltage maintenance calculation means 7 based on the calculated system change speed. Further, the control amount correction means 14 calculates the change speed of the load change of the power system as the system change speed, calculates a correction coefficient of the control amount based on the calculated system change speed, and calculates the control amount correction coefficient by the voltage maintenance calculation means 7. The control amount is corrected. Other configurations are the same as those of the first embodiment shown in FIG. 1, and therefore, the same components are denoted by the same reference symbols and description thereof will be omitted.

According to the third embodiment, when the load change is abrupt, the control period is advanced and the control amount correction coefficient is increased, so that the voltage maintenance calculation means 7 calculates the control amount. Voltage control with good responsiveness according to the system change speed can be performed.

Next, a fourth embodiment of the present invention will be described. FIG. 8 is a block diagram showing a fourth embodiment of the present invention. This fourth embodiment is different from the third embodiment shown in FIG. 7 in that control data storage means 16 stores a control cycle and a control amount correction coefficient when the control result of the power system is good. The control speed correction means 9 selects the control cycle when the control cycle at the same system change speed as the calculated system change speed is stored in the control data storage means 16. As described above, the control amount correction unit 14 selects the control amount correction coefficient when the control amount correction coefficient at the same system change speed as the calculated system change speed is stored in the control data storage unit 16. Things.

FIG. 9 is a flowchart showing the operation of the voltage reactive power control device 1 according to the fourth embodiment of the present invention. First, it is determined whether or not the control result of the voltage maintenance calculation of the previous day by the voltage maintenance calculation means 7 was good (S3).
1) If the control result of the voltage maintenance calculation is good, the system change speed, control cycle, and control amount correction coefficient of the previous day are stored in the control data storage unit 16 (S3).
2).

In this state, 30 of the total demand forecast data 11
The load change amount per minute is examined, the system change speed 12, which is the change speed of the load change of the power system, is calculated (S33), and compared with the system change speed stored in the control data storage unit 16 (S34). When the change speed having the same characteristic as the calculated system change speed is stored, the control cycle 13 and the control amount correction coefficient 15 are selected (S35).
The voltage maintenance calculation unit 7 performs the voltage maintenance calculation based on the selected good control cycle 13 and control amount correction coefficient 15 of the previous day (S37).

On the other hand, if the change speed having the same characteristic as the calculated system change speed is not stored, the control speed correction means 9 calculates the control cycle 13 corresponding to the system change speed, The control amount correction coefficient 1 by the correction means 14
5 is calculated (S36). Then, voltage maintenance calculation is performed based on the calculated control cycle 13 and control amount correction coefficient 15 (S37).

According to the fourth embodiment, the control data storing means stores a good control cycle and a control amount correction coefficient of the control result, and when there is a system change speed of the same characteristic, the control data storing means stores the control characteristic correction coefficient. Since the bus voltage Vi at the monitoring point i in the power system is appropriately maintained at the allowable value by using the control cycle and the control amount correction coefficient, the problem of the delay in voltage control due to the influence of the daily load can be solved.

[0050]

As described above, according to the present invention, the system change speed is calculated from the total demand forecast data, and the control period is changed or the control amount is corrected based on the system change speed. Since the correction coefficient is added, the bus voltage of the power system can be appropriately maintained at the reference voltage.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a calculation content of a control speed correction means according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a method of determining a control cycle in a control speed correction unit according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

FIG. 5 is a block diagram showing a calculation content of a control amount correcting means according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram of a method for determining a control amount correction coefficient by a control amount correction unit according to the second embodiment of the present invention.

FIG. 7 is a block diagram showing a third embodiment of the present invention.

FIG. 8 is a block diagram showing a fourth embodiment of the present invention.

FIG. 9 is a flowchart illustrating an operation of the voltage reactive power control device according to the fourth embodiment of the present invention.

FIG. 10 is a block diagram of a conventional example.

FIG. 11 is a flowchart showing the content of calculation by a voltage maintenance calculation unit in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 voltage reactive power control device 2 computer 3 power system network 4 control equipment 5 monitoring point 6 cyclic digital telemeter 7 voltage maintenance calculation means 8 reference voltage setting means 9 control speed correction means 10 total demand forecast setting means 11 total demand forecast data 12 System change speed 13 Control cycle 14 Control amount correction means 15 Control amount correction coefficient 16 Control data storage means

Claims (4)

[Claims] 1. A voltage reactive power control device for a power system, wherein a control device for supplying reactive power is controlled such that a bus voltage of the power system becomes the reference voltage. A reference voltage setting means for setting, and a control amount to each of the control devices based on a deviation between a bus voltage of the power system started at a predetermined control cycle and a reference voltage set in the reference voltage setting means. And a control speed correction unit that calculates the change speed of the load fluctuation of the power system as a system change speed and changes the control cycle of the voltage maintenance calculation unit based on the calculated system change speed. And a voltage reactive power control device for an electric power system. 2. A voltage reactive power control device for a power system, wherein a control device for supplying reactive power is controlled such that a bus voltage of the power system becomes the reference voltage. A reference voltage setting means for setting, and a control amount to each of the control devices based on a deviation between a bus voltage of the power system started at a predetermined control cycle and a reference voltage set in the reference voltage setting means. And a voltage maintenance calculation means for calculating the load change rate of the power system as a system change rate, calculating a correction coefficient of the control amount based on the calculated system change rate, and calculating by the voltage maintenance calculation means. And a control amount correction unit for correcting the control amount obtained. 3. A voltage reactive power control device for a power system, wherein a control device for supplying reactive power is controlled such that a bus voltage of the power system is equal to the reference voltage. A reference voltage setting means for setting, and a control amount to each of the control devices based on a deviation between a bus voltage of the power system started at a predetermined control cycle and a reference voltage set in the reference voltage setting means. And a control speed correction unit that calculates the change speed of the load fluctuation of the power system as a system change speed and changes the control cycle of the voltage maintenance calculation unit based on the calculated system change speed. And calculating a change rate of a load change of the power system as a system change speed, calculating a correction coefficient of the control amount based on the calculated system change speed, and And a control amount correction means for correcting the control amount calculated in the step. 4. A control data storage unit for storing the control cycle and a control amount correction coefficient when the control result of the power system is good is provided, wherein the control speed correction unit calculates the control speed. When the control cycle at the same system change speed as the system change speed is stored in the control data storage unit, the control period is selected, and the control amount correction unit is the same as the calculated system change speed. 4. The voltage reactive power of the power system according to claim 3, wherein when the control amount correction coefficient at the system change speed is stored in the control data storage unit, the control amount correction coefficient is selected. Control device.