JP2012039818A - Voltage reactive power control system - Google Patents

Abstract

The present invention provides a voltage reactive power control system in which a reactive power compensator can steadily bring an output close to the device capacity as close to zero as possible by a voltage reactive power control device.
An output to a power system of a reactive power compensator is measured, and when the fluctuation range is within a certain range and continues for a specified time, it is determined that steady output is being performed. Then, the phase adjusting equipment 4 (for example, a power capacitor or a shunt reactor) corresponding to the output is operated. Thereby, the steady output of the reactive power compensator 9 is canceled.
[Selection] Figure 1

Description

  The present invention relates to a voltage reactive power control system, and relates to cooperative control of a voltage reactive power control device and a reactive power compensation device installed in a substation.

  Generally, in a power system, the voltage and reactive power of the power system change depending on the state of the load. For this reason, when operating the power system, the voltage and reactive power are adjusted within the target values. The adjustment of voltage and reactive power is performed by controlling a voltage reactive power control device with a voltage reactive power control (hereinafter referred to as VQC) device. For example, a method described in Patent Document 1 is known.

  As the voltage reactive power control device, a phase adjusting facility such as a power capacitor (SC) or a shunt reactor (ShR) provided in the power system, or a tap of a transformer with a tap is used. The VQC device controls the tap position of the tapped transformer and the phase adjusting equipment based on the voltage and reactive power of the power system, the tap position of the transformer with tap and the operation information of the phase adjusting equipment, respectively, and the voltage and reactive power. Is adjusted to be within the target value.

JP 2003-259555 A

  When a high-speed response is required for substation voltage reactive power control, the response speed of the VQC device is slow, so a reactive power compensator may be separately installed. The reactive power compensator outputs at a high speed to maintain the power system fluctuation and voltage, but if the output is constantly close to the equipment capacity, the equipment capacity will be full with respect to the next power system fluctuation. And may not be able to fully function.

  The present invention is an invention for solving the above-described problem, and an object thereof is to provide a VQC system in which a steady output of a reactive power compensator can be made as close to zero as possible by a VQC device.

  In order to achieve the above object, the VQC system of the present invention measures the output of the reactive power compensator to the power system, and when the fluctuation range is within a certain range and continues for a specified time, it is steady. It is determined that a normal output is being performed, and a phase adjusting device (power capacitor or shunt reactor) corresponding to the output is operated. This cancels the steady output of the reactive power compensator.

  Although the VQC device normally performs integral control, control for operating the phase adjusting device based on the output value to the power system of the reactive power compensator is not performed based on the deviation from the command value. Will be output as However, controlling a large amount of phase adjusting equipment simultaneously only causes disturbance to the system, so the phase adjusting equipment is controlled one by one, and the control is continued until the required amount is reached. If the required amount is larger than the equipment to be controlled, the control is performed up to the point where all the equipment to be controlled is controlled. However, if cooperation with the adjacent substation is possible, the shortage capacity must be controlled at the adjacent substation. It is also possible to secure the required amount. In addition, although the VQC system is targeted, since the effect of tap control is small, it can be replaced with a phase control device without tap control.

  According to the present invention, the steady output of the reactive power compensator can be brought as close to zero as possible by the VQC device.

It is a block diagram which shows embodiment of the VQC system of this invention. It is explanatory drawing which shows the process of a VQC apparatus. It is explanatory drawing which shows the selection method of the control object of a control object selection part. It is a flowchart which shows the process of the output adjustment of the reactive power compensation apparatus by a VQC apparatus.

Hereinafter, the VQC system of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of the VQC system of the present invention. The VQC system of the present invention is installed in a substation where a reactive power compensator (for example, STATCOM (STATic synchronous compensator), SVC (Static Var Compensator)) is provided. As shown in FIG. 1, the VQC system includes a transformer 3 with a step-down voltage connected to a high-voltage bus 1 and a low-voltage bus 2 and a phase-adjusting facility connected to the tertiary side of the transformer 3 with a tap. 4, a reactive power compensator 9 connected to the low-voltage bus 2, and a VQC device 10. The phase adjusting equipment 4 includes a plurality of shunt reactors (ShR) and a power capacitor (SC).

  The primary side of the transformer 3 with a tap is connected to a current detection unit 7 (current detection unit), and the high voltage bus 1 and the low voltage bus 2 are connected to voltage detection units 5 and 6 (voltage detection unit), respectively. A current detector 8 (current detector) is connected to the low-voltage bus 2 side of the reactive power compensator 9, and the measured value is periodically taken into the VQC device 10.

  1 includes an effective value calculation unit 11, a target deviation detection unit 12, a control target selection unit 13, a control output unit 13a, an output switching unit 14, an integration control unit 15, a reactive power compensator output calculation unit. 16, the control number calculating part 17 and the control phase selection part 18 are comprised. The processing of each unit will be described later with reference to FIG.

  The relationship between the VQC system, the reactive power compensator 9 and the conventional VQC device will be described. In order to protect and stabilize the system, the reactive power compensator 9 such as STATCOM or SVC operates at high speed for high-speed system voltage fluctuation and absorbs the fluctuation. On the other hand, a conventional VQC device operates a circuit breaker of a phase adjusting facility such as SC or ShR so as to drive a steady voltage fluctuation (for example, fluctuation of about 1 minute) into a predetermined voltage range.

  When a system fault occurs, the reactive power compensator 9 operates normally after the accident period and after the accident is removed, and the VQC apparatus does not normally operate. The VQC device is equipped with a normal voltage drop detection relay and a no-voltage detection relay. When the voltage drop detection relay is operating, the addition in the integral calculation is locked, and when no voltage is detected, the integral calculation is reset. The output is not inadvertently output during the accident period.

Therefore, the reactive power compensator 9 that has been operated due to the influence of an accident often enters a steady state in a state where the reactive power is constantly output. The VQC device attempts to control the phase adjusting equipment 4 by integrating the deviation between the set value and the voltage value (integral time constant is about 30 seconds to 1 minute) with respect to the fluctuation of the voltage value after the accident removal. If the reactive power compensator 9 is provided side by side and sufficient capacity is secured even for steady fluctuations, voltage control in the VQC device becomes unnecessary. However, in reality, it is uneconomical to secure a capacity sufficient for steady voltage fluctuations (changes associated with daily load fluctuations) with the reactive power compensator, and the system is operated in combination with the phase adjusting equipment 4. .
Usually at each substation,
The actual situation is that the capacity of the reactive power compensator 9 <the total capacity of the phase adjusting equipment 4.

  In the VQC system of this embodiment, the reactive power compensator 9 responds to fluctuations of about several seconds such as at the time of an accident, and with respect to steady fluctuations, assuming that the VQC apparatus 10 performs control, steady fluctuations are only used. As a function of the VQC device that drives into a certain voltage range, it becomes invalid by adding a control that makes the steady output of the reactive power compensator 9 zero (in reality, the capacity of one unit of the phase adjusting equipment or less). The power compensation device 9 is intended to secure a capacity capable of responding to an accident without changing the power compensation device 9.

  FIG. 2 is an explanatory diagram showing processing steps of the VQC device. The VQC device 10 includes a voltage V1 (state quantity) of the high voltage bus 1 measured by the voltage detection unit 5, a voltage V2 (state quantity) of the low voltage bus 2 measured by the voltage detection unit 6, and a current detection unit 7. The measured primary side current I1 of the transformer with tap 3 and the output current Ic of the reactive power compensator 9 measured by the current detection unit 8 are periodically fetched.

  The effective value calculator 11 outputs the effective values of the voltages V1 and V2 and the current I1, and outputs the effective value of the primary passing reactive power Q1 of the transformer 3 with a tap. The effective value calculation unit 161 outputs an effective value of the output reactive power Qc of the reactive power compensator 9. Reactive power Q1 is calculated from voltage V1 and current I1, and reactive power Qc is calculated from voltage V2 and current Ic.

  Next, the target deviation detector 12 detects the deviation between the effective value of the voltages V1 and V2 and the reactive power Q1 obtained by the effective value calculator 11 and the target value. The target value is expressed as a reference voltage or a reference reactive current value ± dead band width, and may be stored in the VQC device 10 as a set value in advance, or a system monitoring device (not shown) may be collectively included in the vicinity of nearby substations. A value that minimizes the loss may be calculated by power flow calculation or the like, and may be sequentially transmitted to the VQC device 10.

  In the control target selection unit 13, from the result of the target deviation detection unit 12, the state information 20 indicating the operation state of the phase adjustment equipment 4 and the tap position state of the tap transformer 3, the phase adjustment equipment 4 and the tap transformer 3 Among them, the most suitable one for reducing the target deviation is selected as a control target. A method of selecting a control target will be described with reference to FIG.

  FIG. 3 is an explanatory diagram illustrating a method of selecting a control target by the control target selection unit. FIG. 3A shows a case where the voltages V1 and V2 are used as the control plane. The inside of the broken line is the dead band width, and the voltages V1 and V2 are adjusted within this range. In FIG. 3A, when both of the voltages V1 and V2 are higher than the target values, the voltages V1 and V2 are set depending on whether a part of the power capacitor of the phase adjusting equipment 4 is turned off or a part of the shunt reactor is turned on. It shows that it is within the target value. The same applies to other regions, and when the voltages V1 and V2 are both lower than the target values, the voltages V1 and V2 can be changed depending on whether a part of the power capacitor of the phase adjusting equipment 4 or a part of the shunt reactor is turned off. Within the target value. When the voltage V1 is lower than the target value and the voltage V2 is higher than the target value, the tap of the tapped transformer 3 is appropriately lowered, and when the voltage V1 is higher than the target value and the voltage V2 is lower than the target value, the tap By appropriately raising the tap of the attached transformer 3, the voltages V1 and V2 are kept within the target values. In this way, the control object and the control content are determined depending on where the voltages V1 and V2 are on the control plane. There are a number of methods for determining the boundary of each control content, but the VQC device 10 may be set so that the hunting phenomenon does not easily occur. FIG. 3B shows a case where the control plane is set to the voltage V2 and the reactive power Q1, and the main point is the same as FIG. 3A. The inside of the broken line is the dead band width, and the voltage and reactive power are adjusted within this range.

  The integration control unit 15 successively integrates the deviation amounts detected by the target deviation detection 12, and when the integration amount reaches an integration expiration level such as dead band width × integration time, an operation command is sent to the control output unit 13a. To do. The control output unit 13 a gives an output switching command to the output switching unit 14 with respect to the phase adjusting equipment 4 and the tapped transformer 3 selected by the control target selecting unit 13 by an operation command of the integration control unit 15.

  The reactive power compensator output calculation unit 16 calculates the difference between the effective value of the reactive power Qc output from the effective value calculation unit 161 and the average value calculated based on the reactive power Qc by the averaging calculation unit 162. When the steady state determination unit 163 determines that the deviation is within a change range determined in advance by setting or the like, and that the state has continued for a period longer than the confirmation time for recognizing the steady state, the correction control command is output. I do.

  The number-of-controls calculation unit 17 determines the number of control units that output a control command by adding the rated capacities of the respective phase adjusting facilities based on the phase adjusting capacity information 164 within a range not exceeding the reactive power Qc. If the rated capacities of the respective phase adjusting equipments are almost the same, the phase adjusting equipments may be controlled in a predetermined order so that the control does not concentrate on the specific phase adjusting equipment.

  The control phase selection unit 18 sets the integral value of the integral control to zero because there is a high possibility of hunting if the output of the integral control is executed until the control of the calculated number of controlled units is completed by the correction control command. Continue resetting. In addition, the control phase selection unit 18 selects a phase adjustment facility to be controlled based on the number of controlled units calculated by the control number calculation unit 17 and instructs the output switching unit 14 to operate the control output.

  FIG. 4 is a flowchart showing the output adjustment processing of the reactive power compensator by the VQC device. With reference to FIG. 4, the process shown in FIG. 2 will be described more specifically. The reactive power compensator output calculation unit 16 measures the output of the reactive power compensator 9 (step S31), and determines whether or not the measured value is in a steady state (step S32). When it is in a steady state (step S32, Yes), the process proceeds to step S33, and when it is not in a steady state (step S32, No), the process returns to step S31.

  In step S33, the reactive power compensator output calculation unit 16 determines whether or not the steady state has continued for the set period or longer. If the steady state has continued for the set period or longer (step S33, Yes), the process proceeds to step S34. If the steady state has not continued for the set period or longer (step S33, No), the process returns to step S31.

  In step S34, the control number calculation unit 17 determines whether or not the output of the reactive power compensator 9 is an output of one or more phase adjusting equipments. When it is the output of one or more phase adjusting equipment (step S34, Yes), it progresses to step S35, and when it is not the output of one or more phase adjusting equipment (step S34, No), it returns to step S31.

  In step S <b> 35, a lock command for conventional VQC control is commanded to the integral control unit 15 via the control phase selection unit 18. Then, the control phase selection unit 18 selects the phase adjustment equipment 4 to be controlled based on the number of controlled units calculated by the control number calculation unit 17 (step S36), and instructs the output switching unit 14 to output the control ( Step S37). The control phase selection unit 18 determines whether or not the circuit breaker pallet of the phase adjusting equipment is inverted (step S38). When the circuit breaker pallet is inverted (step S38, Yes), the process proceeds to step S39. When the pallet is not reversed (No at Step S38), the process returns to Step S38. The circuit breaker pallet means pallet information of pallet contacts that are turned on and off in accordance with the opening and closing of the circuit breaker.

  In step S39, the control phase selection unit 18 instructs the integration control unit 15 to unlock the conventional VQC control, and returns to step S31.

  In summary, in the present embodiment, the VQC device 10 integrates the deviation between the set value and the detected voltage value, and outputs a control output when the integrated value exceeds a certain value. Operate the circuit breaker (voltage capacitor (SC) or shunt reactor (ShR)). Therefore, if the circuit breaker of the phase adjusting equipment 4 is forcibly operated so as to take over the reactive power output by the reactive power compensator 9, it competes with the function of the conventional VQC device 10, and the phase adjusting equipment 4 The operation of the circuit breaker may be excessive due to hunting.

  Therefore, the VQC device 10 confirms that the output of the reactive power compensator 9 is a steady output (confirmed by staying within a certain fluctuation range for a set time or more), and the output is VQC. If the reactive power amount is one or more units of the phase adjusting equipment 4 that is controlled by the device 10, the output of the function of the conventional VQC device 10 is locked (realized by resetting the integration) and then the phase adjusting equipment. 4 circuit breaker is operated.

When there are multiple phase adjusting equipments 4
(1) Select a combination of the phase adjusting equipment 4 that is as close to the value output by the reactive power compensator 9 as much as possible. (2) If the equipment has the same capacity or a plurality of combinations have the same capacity, Use a phase breaker that requires fewer operations as a guideline.

  In principle, the number of circuit breakers in the phase adjusting equipment 4 is one by one, and the circuit breaker of the next phase adjusting equipment 4 is operated after a time until the fluctuation of the system voltage due to the introduction of the phase adjusting equipment 4 is reduced. If it is clear that operating the circuit breaker of the phase adjusting equipment 4 has little effect on the system, a setting that allows simultaneous operation of a plurality of units is provided in the VQC device 10 in advance, and a plurality of units are operated simultaneously. May be. In addition, the output lock by the function of the conventional VQC device 10 is continued until all of the pallet of the phase breaker controlled by the VQC device 10 are reversed.

  The voltage reactive power control system according to the present embodiment includes buses 1 and 2 having different power system voltage levels, a transformer 3 with a tap connected between them, and a state of a primary side and a secondary side of the transformer 3 with a tap. Phase adjusting equipment 4 for controlling quantities (for example, voltages V1, V2), voltage reactive power control apparatus 10 for monitoring state quantities, and reactive power compensator 9 for controlling reactive power connected to bus 2 In this system, the voltage reactive power control device 10 is based on the state quantity information, the tap position of the transformer 3 with taps, and the state information 20 which is operation information of the phase adjusting equipment 4. 3 is a voltage reactive power control system that outputs control commands to 3 and the phase adjusting equipment 4 to adjust the state quantity within a target value.

  The voltage reactive power control device 10 monitors the output of the reactive power compensation by the reactive power compensation device 9, the output of the reactive power compensation is in a steady state, and the capacity of one or more units of the phase adjusting equipment 4 is steadily increased. Is output so that the control command for controlling based on the deviation between the state quantity and the target value is not issued, and the reactive power compensation device 9 is configured to reduce the reactive power compensation output. The number of the phase adjusting equipment 4 to be controlled can be calculated from the output, and a control command can be sequentially output to the phase adjusting equipment 4 until the number of the phase adjusting equipment is satisfied.

  In the voltage reactive power control system, when the output of the reactive power compensator 9 in the steady state is equal to or greater than the capacity of the controllable target equipment, the capacity exceeds the adjacent substation after controlling all the controllable target equipment. It is advisable to request a certain amount of control.

  In the voltage reactive power control system, the phase adjusting capacity controlled by the voltage reactive power control apparatus 10 is transmitted to the reactive power compensator 9, and the phase adjusting capacity corresponding to the target value of the reactive power control of the reactive power compensator 9 is controlled. It is good to reduce it forcibly.

  According to this embodiment, the output of the reactive power compensator 9 can be reduced as close to zero as possible while minimizing the influence on the system, and the reactive power compensator 9 can be applied to the next power system fluctuation. Can fully function.

DESCRIPTION OF SYMBOLS 1 High voltage bus 2 Low voltage bus 3 Transformer with tap 4 Phase adjustment equipment 9 Reactive power compensation device 10 VQC device 11 RMS value calculation unit 12 Target deviation detection unit 13 Control object selection unit 14 Output switching unit 15 Integration control unit 16 Reactive power compensation Device output calculation unit 17 Control unit calculation unit 18 Control phase selection unit 20 Status information 161 RMS value calculation unit 162 Averaging calculation unit 163 Steady state determination unit 164 Phase modulation capacity information I1 Current Ic Output current Q1 Reactive power Qc Output reactive power V1, V2 voltage (state quantity)

Claims (3)

Power buses with different voltage levels of the power system, tapped transformers connected between them, phase adjusting equipment for controlling the primary and secondary state quantities of the tapped transformer, and the state quantities respectively In a system having a voltage reactive power control device to be monitored and a reactive power compensation device capable of controlling the reactive power connected to the bus, the voltage reactive power control device includes the state quantity information and the tapped transformer. A control command is output to the transformer with tap and the phase adjusting equipment to adjust the state quantity within a target value based on the tap position of the appliance and the state information which is the operation information of the phase adjusting equipment. A voltage reactive power control system,
The voltage reactive power control device monitors the output of the reactive power compensation by the reactive power compensation device, the output of the reactive power compensation is in a steady state, and the capacity of one or more units of the phase adjusting equipment in a steady state Is output so that the control command for controlling the state quantity is not based on the deviation between the state quantity and the target value, and in order to reduce the output of the reactive power compensation, A voltage reactive power control system, wherein the number of phase adjusting equipment to be controlled is calculated from the output of the reactive power compensator, and control commands are sequentially output to the phase adjusting equipment until the number of phase adjusting equipment is satisfied. The voltage reactive power control system according to claim 1,
If the output of the reactive power compensator in the steady state is equal to or greater than the capacity of the controllable target equipment, control all of the controllable target equipment, and then request control over the capacity to the adjacent substation. A voltage reactive power control system characterized by that. The voltage reactive power control system according to claim 1,
Transmitting the phase-adjusting capacity controlled by the voltage reactive power control device to the reactive power compensator, and forcibly reducing the phase-adjusting capacity for controlling the reactive power control target value of the reactive power compensator. Characteristic reactive power control system.

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