JP2009284611A - Device and method for system stabilization - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize isolated operation of a generator after a system separating accident involving voltage drop occurs and system separation takes place. <P>SOLUTION: A reference stabilization control amount is computed from load flow balance data obtained through a load-flow calculation. The reference stabilization control amount is a stabilization control amount required in a system separating accident that does not involve voltage drop. The computed reference stabilization control amount is corrected using a correction coefficient for reactive power transient variation obtained through transient stability calculation. The corrected stabilization control amount is tabulated using residual voltage as a parameter to generate a stabilization control amount table. A controlled object is selected according to preset priorities. Based on the contents of the stabilization control amount table, stabilization control preset values including the controlled object and a control amount are tabulated using residual voltage as a parameter to generate a stabilization control preset table. If system separation takes place, a stabilization control preset value corresponding to a measurement value of residual voltage is selected and stabilization control is instantaneously carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power system that supplies power to a load facility by connecting a power system of a demand facility configured with a power generation facility and a load facility and a power system network of an electric power company, etc. The present invention relates to a system stabilization device and a system stabilization method in an isolated system for performing isolated operation with a power generation facility in the isolated system and supplying load power stably when a system separation accident occurs due to a system accident, etc. Is.

  FIG. 7 is a configuration diagram of a system stabilizing device in a conventional single separation system as disclosed in Patent Documents 1 to 5. In FIG. 7, 1 is a substation bus of the main system, 2 is a transmission line for connection between the main system and the separation system, 3 is a circuit breaker of the substation of the main system, and 1A to 1C are in the separation system 2B to 2C are transmission lines in the separation system, 3A to 3D are circuit breakers, 4A to 4D are sensors for detecting and detecting the transmission line current (current transformer), and 5A is a detection and detection of the bus voltage. Sensors (transformers) 6A to 6D are input cables for taking in currents and voltages, 7A to 7D are input of switching information of the circuit breakers 3A to 3D, power limit (power cutoff) and load limit ( An input / output cable for outputting a command signal (load cutoff), 8 is a generator in the separated system, and 9a to 9c are loads (load facilities) in the separated system.

  10 is for maintaining the frequency and voltage in the separated system by cutting off the generator 8 or the loads 9a to 9c when the separated system is separated from the main system due to a system separation failure in the transmission line 2 or the bus 1 It is a system stabilization device. 11 is a phase adjusting facility for adjusting the voltage of the bus 1A, and 12B to 12C are transformers for converting the voltage in the separation system.

  The system stabilizing device 10 obtains values such as bus voltage, load amount, power generation amount, interconnection current flow, phase adjustment amount, etc. in the separated system from the input cables 6A to 6D, and performs the power flow calculation for a certain period of time. Perform every time. When the power transmission line 2 is interrupted and system separation occurs in the separated system, the system stabilizing device 10 recognizes that the power transmission line 2 is interrupted and system separation has occurred, for example, from a signal obtained through the input cable 6A. Then, the system stabilizing device 10 performs power flow calculation in the separated system based on various information before the system separation occurs, and calculates the frequency and voltage of the single separated system after the system separation occurs.

  When the values of the frequency and voltage of the isolated system after the system separation occur deviate from the operation allowable value, the system stabilizing device 10 sets the stabilization control amount so that the system can be operated within the operation allowable value. The control command is output to the generator 8 and the loads 9a to 9c through the input / output cables 7B and 7C.

  In such a conventional system stabilizing device, the necessity of control is determined from the frequency and voltage fluctuation range of the isolated system and the operation allowable value. If control is necessary, either the generator 8 or the load 9 is determined. The frequency and voltage of the single isolated system are controlled by shutting off the power supply and / or controlling the phase.

Japanese Patent Laid-Open No. 7-241035 JP 2001-359241 A JP 2004-72882 A JP 2004-72883 A JP 2004-72884 A

  The conventional system stabilization device as described above performs steady power flow calculation before and after system isolation based on system information such as the power flow, voltage, and circuit breaker switching status before the occurrence of a system isolation accident. Then, the control amount (load limiting amount, power source limiting amount, phase adjustment control amount) corresponding to the unbalanced amount of the tidal current obtained as a result is calculated and controlled.

  On the other hand, in load equipment with constant power characteristics such as an induction motor, the current value increases when the system voltage decreases, and therefore the amount of reactive power consumed in the line reactance (for example, the transformer 12C in FIG. 7) in the system increases. There is a characteristic to do. In addition, phase adjusting equipment such as a power capacitor has a characteristic that the amount of phase adjustment (the amount of reactive power supplied) decreases when the system voltage decreases. For this reason, in the actual factory distribution system that is a complex of these devices, when a system separation accident with a voltage drop occurs, the unbalance amount of reactive power immediately after system separation becomes a characteristic that increases transiently. .

  From the above, when a conventional system stabilization device is applied to a factory distribution system with the above characteristics, a "system separation accident with a significant voltage drop" occurs due to a short circuit accident or a ground fault. For example, there is a problem that the phase control amount calculated by the system stabilizing device is insufficient with respect to the phase control amount actually required. Furthermore, when the shortage of this phase adjustment control is large, not only the system voltage recovery control by the generator that operates alone is delayed, but the generator overcurrent continues for a long time. Automatic stop by protective action. In other words, there was a possibility that the single operation of the generator would fail.

  In view of the above-described problems of the prior art, the present invention can be applied to a power supply system in which inductive loads and capacitive loads having constant power characteristics coexist, even when a system separation accident with a voltage drop occurs. An object of the present invention is to provide a system stabilization device and a system stabilization method capable of ensuring the independent operation of a generator after system separation.

In the occurrence of a system separation accident in the power system, the system stabilization device of the present invention is configured to connect a busbar in the separation system connected to the main system via a connection line, a circuit breaker, and each transmission line in the separation system. In the separation system in the separation system including the first sensor for detecting the current, the second sensor for detecting the voltage of the bus in the separation system, the generator, the load facility, and the phase adjusting facility A system stabilization device for stabilizing an isolated operation by a generator of the system, wherein the system configuration detection detects a system configuration in the separated system at a predetermined cycle based on a signal indicating an open / close state from the circuit breaker Voltage for each facility including a transmission line, a load facility, a generator, and a phase adjusting facility in the separation system based on the means, the current signal from the first sensor, and the voltage signal from the second sensor. , Frequency, current, active power, and nothing Based on a power flow information detecting means for detecting power flow information including power and a voltage signal from the second sensor, a voltage of a bus in the separated system is detected at a speed higher than the predetermined period, and the system System voltage detection means for detecting a transient fluctuation value of the bus voltage in the separated system when a separation accident occurs, online system information including the system configuration and the power flow information, and transient characteristics of the load equipment Based on the data, the voltage characteristic data of the phase adjusting equipment, and the transient characteristic data including the overexcitation protection operation characteristic of the generator, the transient stability is calculated, and based on the result of the calculation, Transient stability analysis means for calculating a correction coefficient for the reactive power transient fluctuation amount immediately after the occurrence of the system separation accident, and the residual voltage of the bus in the separated system immediately before the occurrence of the system separation accident are parameterized. A stabilization control preset value indicating a control amount for stabilizing and controlling a control target in the separated system when a system separation accident accompanied by a drop in the voltage of the bus in the separated system occurs. System stabilization control preset table generating means for generating a control control preset table using a result of power flow calculation based on the online system information and a correction coefficient of the reactive power transient fluctuation amount, and a breaker of the interconnection line Using the system separation signal indicating the system separation detected from the open / closed state of the trigger as a trigger, the stabilization control preset value is selected from the stabilization control preset table based on the transient fluctuation value of the bus voltage in the separated system Stabilization control execution means for instantaneously executing stabilization processing, and a stabilization control command based on the selected stabilization control preset value to the device to be controlled A stabilization processing output means for outputting, and compensating for an imbalance of reactive power when a system separation accident accompanied by a transient voltage drop of a bus in the separated system occurred, and a system separation accident occurred It is characterized by stabilizing the single operation by the generator in the separated system later.
In another embodiment of the present invention, there is provided a system stabilizing device for stabilizing an isolated operation by a generator in a separated system separated from a main system by the occurrence of a system separation accident in the power system, A tidal current calculation execution means for executing tidal current calculation using tidal current information in the equipment in the separated system and configuration information in the separated system; and when the voltage of the bus in the separated system is reduced due to the system separation accident Reactive power in the separated system is obtained by calculating transient stability, and using the obtained reactive power, a correction coefficient for estimating a transient fluctuation amount of the reactive power when the system separation accident occurs is calculated. A stabilization control amount obtained by using the transient stability analysis means and the result of the power flow calculation, and a reference stabilization control amount required at the time of a system separation accident without a voltage drop is calculated using the correction coefficient. Stabilized control amount table generating means for generating a stabilized control amount table in which the corrected and stabilized reference stabilization control amount is stored with the residual voltage of the bus in the separated system as a parameter when the system separation accident occurs And selecting a control target in the separated system according to a preset priority, and a control amount for stabilizing the selected controlled object when a system separation accident accompanied by a decrease in the voltage of the bus occurs. A stabilization control preset table is generated by using the stabilization control amount table, which stores the stabilization control preset value shown as a parameter with the remaining voltage of the bus in the separated system accompanying the occurrence of the system separation accident. When the system separation accident occurs, the stable control preset table generating means generates the stable based on the transient fluctuation value of the bus voltage in the separated system. Select control preset value, and having a stabilization control execution means for executing the control of the controlled object according to the selected stabilizing control preset value.

  In the system stabilization method of the present invention, in the event of a system separation accident in the power system, the bus in the separation system connected to the main system via the interconnection line, the circuit breaker, and each transmission line in the separation system In the separation system in the separation system including the first sensor for detecting the current, the second sensor for detecting the voltage of the bus in the separation system, the generator, the load facility, and the phase adjusting facility A system stabilization method for stabilizing an isolated operation by a generator of a load, comprising: a dynamic characteristic of a load group including the load facility having a constant power characteristic; and a line reactance between the load group and the generator group And calculating the transient stability in consideration of the dynamic characteristics of the generator group including the reactive power limiting control operation and the dynamic characteristics of the phase adjusting equipment, and based on the calculated results, To estimate the amount of transient fluctuation of reactive power when it occurs Generating a reactive power transient fluctuation correction coefficient as a parameter of a residual voltage of a bus in the separation system immediately before the occurrence of the system separation accident, a system configuration in the separation system, and the inside of the separation system Stabilized control amount calculated from data on tidal current balance obtained from tidal current calculation based on on-line grid information including tidal current information on other facilities, and is necessary for system separation accidents without voltage drop The stabilization control amount is corrected by the correction coefficient of the reactive power transient fluctuation amount, and the corrected reference stabilization control amount is stored as a parameter of the residual voltage of the bus in the separated system immediately before the system separation accident occurs. Generating a stabilized control amount table, selecting a control target in the separation system according to a preset priority order, and generating a bus line in the separation system. The stabilization control preset value indicating the control amount for stabilizing control of the selected control object when a system separation accident with a decrease in pressure occurs is the value in the separated system immediately before the system separation accident occurs. A step of generating a stabilization control preset table stored using the remaining voltage of the bus of the system as a parameter using the stabilization control amount table, and a voltage of the bus in the separated system when the system separation accident occurs A step of selecting the stabilization control preset value from the stabilization control preset table on the basis of the transient fluctuation value and executing the stabilization control instantaneously. Compensation of the reactive power imbalance when a system separation accident accompanied by a voltage drop occurs, and the independent operation by the generator in the separation system after the system separation accident occurs It is characterized by stabilizing the rotation.

  According to the present invention, even if there is a system separation accident accompanied by a voltage drop, power generation due to a shortage of reactive power supply, etc. is compensated as soon as possible by compensating transient transient power imbalance after system separation. The failure of the independent operation of the machine is avoided as much as possible, and stable power supply is possible even after system separation.

The form for implementing the system | strain stabilization apparatus of this invention is demonstrated in detail with reference to drawings. In each figure, devices, parts, etc. having the same function are denoted by the same reference numerals.
<First Embodiment>
(Configuration of system stabilization device)
FIG. 2 is a schematic diagram of the system stabilization device of the present embodiment and a power system (system configuration) incorporating the system stabilization apparatus.
In FIG. 2, 1 is a substation bus of the main system, 2 is a power transmission line (connection line) for connecting the main system and the separated system, 3 is a circuit breaker of the substation of the main system, 1A to 1C is each bus in the separated system, 2B to 2E are power transmission lines in the separated system, 3A to 3E are circuit breakers, 4A to 4F are each bus 1A to 1C in the separated system, each power transmission line 2B to 2D, each The first sensors (current transformers) 5A to 5C that are taken in to measure the value of the current flowing through the circuit breakers 3A to 3D and the like are used to measure the value of the bus voltage of each bus 1A to 1C in the separation system. It is the 2nd sensor (transformer) to take in.

  6A to 6F are input cables for inputting the current from each of the first sensors 4A to 4F and the bus voltage from each of the second sensors 5A to 5C to the system stabilizing device 10. 7A to 7D are input of switching information of each circuit breaker 3A, 3B, 3E, 3D, power limitation (power cutoff), load limitation (load cutoff), and adjustment from the system stabilizing device 10 to the circuit breaker 3B, etc. It is an input / output cable for outputting at least one command signal for phase control. Reference numeral 8 denotes a generator in the separation system, and 9a to 9c denote loads (load facilities) in the separation system.

  10 shuts off the generator 8 or the loads 9a to 9c or controls the amount of phase adjustment in the phase adjusting equipment 11 when the separation system is separated from the main system due to a separation failure in the power transmission line 2 or the bus 1. Thus, there is a system stabilization device for maintaining the frequency and voltage in the separation system. 11 is a phase-adjusting facility for adjusting the voltage of the bus 1A in the separated system to be the operating voltage (for example, rated voltage), and 12B to 12C are the operating voltage (for example, the rated voltage) for adjusting the voltage in the separated system. It is a transformer for converting to.

  The system stabilization device 10 of the present embodiment includes the first sensors (current transformers) 4A to 4F and the second sensors (transformers) 5A to 5C in the separated systems connected as described above. The signals of each transmission line current and each bus voltage in the separation system are taken in through the input cables 6A to 6F, and the load amount, the power generation amount, the interconnection current, and the adjustment of the input are made from these current signals and voltage signals. Each is converted into a signal of information such as phase amount. Based on this information, the system stabilizing device 10 calculates each tidal current in the separated system after the system separation at regular intervals, for example, every 1 second or less. And the control amount necessary for system stabilization control, that is, the power cutoff amount, the load cutoff amount, and the phase adjustment control to keep the frequency and voltage in the separated system after the system separation occurs within the operation allowable value. Calculate the amount.

  In FIG. 2, for example, when a grid fault such as a short-circuit fault occurs in the interconnection transmission line 2, a protection device (not shown) such as a transmission line protection device provided as a protection device for a substation causes a grid fault. The circuit breaker 3A is cut off based on a command signal from the protection device, and the substation bus 1 of the main system and the substation bus 1A of the separated system are separated from each other, resulting in a system separation accident. In this case, the system stabilization device 10 recognizes that system separation has occurred by taking in the interruption information of the circuit breaker 3A through the input cable 6A, and performs system stabilization control (load control or load interruption, power supply restriction). Or power off and phase adjustment control).

FIG. 1 is a schematic diagram of the internal configuration of the system stabilizing device 10 of the present embodiment. The system stabilizing device 10 according to the present embodiment can be realized by using, for example, a personal computer having various input / output interfaces.
In FIG. 1, 10-1 is a system | strain structure detection means which detects the switching state of each circuit breaker 3A-3E etc. for grasping | ascertaining the system | strain structure in a isolation | separation system | strain. The system configuration detection means 10-1 is for grasping the system configuration (the connection states of the buses 1A to 1C, the generator 8, the load facilities 9a to 9c, and the phase adjusting facility 11) in the separation system that changes every moment. In addition, an auxiliary contact signal indicating the open / closed state of the circuit breakers 3A to 3E is sent from the circuit breakers 3A to 3E in the separation system at a predetermined (constant) period (for example, every 1 second or less) Capture through 7A-7D. The auxiliary contact signals indicating the opened / closed states of the taken circuit breakers 3A to 3E are transmitted to the online data input / output means 10-4 in the form of digital signals.

  10-2 is a tidal current information detecting means for detecting tidal current information of the interconnection line 2, the buses 1A to 1C, the load facilities 9a to 9c, the generator 8, the phase adjusting facility 11, and the like. The tidal current information detecting means 10-2 includes various tidal current information (interconnection line 2, buses 1A to 1C, generator 8, load equipment 9a to 9c, phase adjusting equipment 11 etc.) In order to grasp the frequency F, current I, active power P, reactive power Q, etc., each transmission line (bus 1A-1C, transmission line) detected by the first sensors (current transformers) 4A-4F in the separation system Signals of currents flowing through the electric wires 2, 2B to 2E, etc., and signals of voltages of the buses 1A to 1C detected by the second sensors (transformers) 5A to 5C are taken in through the input cables 6A to 6F. The signal taken into the tidal current information detection means 10-2 is converted into various electric quantities such as voltage V, frequency F, current I, active power P, reactive power Q, etc. using various electric quantity converters such as transducers. Is done. The current information of the interconnection line 2, the buses 1A to 1C, the generator 8, the load facilities 9a to 9c, the phase adjusting facility 11 and the like obtained in this way is the online data input / output means 10-4 in the form of analog signals. Is transmitted to.

  10-3 is a system voltage detecting means for detecting a main system voltage in the separated system. The system voltage detecting means 10-3 is for detecting a transient fluctuation value (transient fluctuation value) of the bus voltage when a system separation accident occurs. The system voltage detecting means 10-3 is connected to the main bus 1A in the separated system in FIG. The voltage signal detected by the installed second sensor (transformer) 5A is, for example, faster than the cycle in which the system configuration detection means 10-1 takes in auxiliary contact signals indicating the open / closed states of the circuit breakers 3A to 3E. Processing is performed to detect a drop in the bus voltage in the separated system, that is, a residual voltage Vp of the bus 1A. The detected residual voltage Vp is supplied to the online data input / output means 10-4 as a continuous analog signal converted by a voltage converter having a fast response or a digital signal converted into a discrete band value by a combination of voltage relays. Communicated. The digital signal converted into a discrete band value is, for example, when the residual voltage Vp is 0 to 10% (0 ≦ Vp ≦ 10% or less), the digital signal Vp1 is turned ON, and the residual voltage Vp is 10 to 20 % Is a digital signal output by a method in which the digital signal Vp2 is turned ON, and similarly, the digital signal VpN is turned ON / OFF in 10% steps. For example, when the residual voltage Vp is 0 to 10% (10% to 20%), 0 to 10% (10% to 20%) of the bus voltage when no drop in the bus voltage in the separation system occurs. %).

  10-4 is an input signal of online system information from the system configuration detecting means 10-1, power flow information detecting means 10-2, system voltage detecting means 10-3, and system separation detecting means 10-8 described later, Online data input / output means for performing input / output processing of an output signal of stabilization processing from a stabilization control execution means 10-9 described later. The online data input / output means 10-4 receives an input signal of online system information that changes from time to time, such as the open / close state of each of the circuit breakers 3A to 3E, each power flow information, each bus voltage, each bus frequency, etc. Input from each detection means 1-10-3 and 10-8 periodically (for example, several hundred milliseconds or less), and the input data is sampled. The signed data (online system information) is transmitted to a power flow calculation execution means 10-5, a transient stability analysis means 10-6, and a stabilization control execution means 10-9, which will be described later, and the stabilization control execution means 10-9. The output signal of the stabilization process from is transmitted to the stabilization process output means 10-10 described later.

  10-5 is a tidal current calculation execution means for performing tidal current calculation in the separated system after system separation and tidal current calculation after performing the stabilization control by the system stabilizing device 10 based on the input online system information. is there. That is, the power flow calculation execution means 10-5 takes in the online system information of the open / closed states of the circuit breakers 3A to 3E into preset system configuration information (power system diagram etc.), thereby changing the system configuration that changes every moment. To figure out. In this state, the tidal current calculation execution means 10-5 estimates the unbalance amount of the supply and demand of the active power P and the reactive power Q in the separated system when the system separation occurs. Moreover, the tidal current calculation execution means 10-5 estimates the voltage and frequency in the separated system after the stabilization control by the system stabilization device 10 is executed. Furthermore, the power flow calculation execution means 10-5 determines that the estimated voltage and frequency are within the operation allowable values set in advance by input, and calculates the stabilization control amount.

  10-6 is transient stability analysis means, which includes online system information including system configuration and power flow information, “transient characteristic data of load facilities 9a to 9c, voltage of phase adjusting equipment 11 set in advance” Based on the characteristic data and the transient characteristic data including the overexcitation protection operation characteristic of the generator 8, the transient stability is calculated at regular intervals, and the reactive power transient fluctuation amount immediately before or after the occurrence of the system separation is calculated. The correction coefficient Kv is calculated. Transient stability means that when the synchronous machine (generator and synchronous motor) is operating in the power system and is subject to system disturbance (transient fluctuation) due to a short-circuit fault, etc. This is the degree to which stable operation can be continued without causing out-of-synchronization (step-out). The transient stability analysis means 10-6 includes various information for transient stability analysis (system configuration, transient characteristic data of the load facilities 9a to 9c, voltage characteristic data of the phase adjusting equipment 11, and transient characteristics of the generator 8). "Simulator for performing transient stability calculation" with preset data etc. is incorporated. As this simulator, since a technique of a known technique can be used, detailed description is omitted here. The transient stability analysis means 10-6 assigns each online system information to the variables of this simulator and executes the calculation of transient stability.

  Then, the transient stability analysis means 10-6 calculates the reactive power transient fluctuation from the “calculated value of the reactive power in the entire separated system when the voltage of the bus in the separated system decreases” obtained by the transient stability calculation. The correction coefficient Kv is calculated. The calculated value of reactive power depends on the residual voltage Vp immediately before (or immediately after) the occurrence of system separation. Therefore, the transient stability analysis means 10-6 calculates the reactive power transient fluctuation correction coefficient Kv when the residual voltage Vp is 100% and when the residual voltage Vp is at least two cases other than that. Then, the correction coefficient Kv of the reactive power transient fluctuation is obtained as a function having the residual voltage Vp as a variable. The reactive power transient correction coefficient Kv does not change so much as to hinder actual operation unless the system configuration and the operating state of the load facilities 9a to 9c change significantly. For this reason, for example, there is no problem even if the calculation of the correction coefficient Kv for the reactive power transient fluctuation is executed by a cycle in minutes or hours, or by manual operation of the operator when changing the system operation. The obtained reactive power transient fluctuation correction coefficient Kv is transmitted to the system stabilization control preset table generating means 10-7.

  The grid stabilization control preset table generation means 10-7 uses the result of the power flow calculation by the power flow calculation execution means 10-5 and the correction coefficient Kv of the reactive power transient fluctuation obtained by the transient stability analysis means 10-6. Thus, a stabilization control preset table using the remaining voltage Vp immediately before (or immediately after) occurrence of system separation as a parameter is generated. Here, the stabilization control preset table is calculated in advance for each control amount and control target for the system stabilization device 10 to perform stabilization control, and the residual voltage Vp immediately before (or just after) the system separation occurs. They are tabulated as parameters. For example, in the case where the balance of the active power P after system separation is in an excessive load state, it is necessary to interrupt the load in accordance with the unbalance amount of the active power P in order to stabilize the frequency. In order to select a load facility 9 to be blocked (controlled) in an amount corresponding to the load cutoff amount (load control amount), a priority order is set in advance for the load facility 9 that can be shut off. In order from the highest load facility 9, one or a plurality of load facilities 9 to be blocked (controlled) are selected. As described above, the selection state of the control object of the stabilization control becomes the stabilization control preset value. Further, as described above, since the load control amount (load cutoff amount) depends on the value of the remaining voltage Vp, the stabilization control preset value (load control amount (load cutoff amount)) corresponding to the value of the residual voltage Vp. Is calculated using the correction coefficient Kv of reactive power transient fluctuation. For example, a stabilization control preset value when the residual voltage Vp is 0 to 10% (0 ≦ Vp ≦ 10%), and a stabilization control preset value when the residual voltage Vp is 10 to 20% (10% <Vp ≦ 20%). Thus, the stabilization control preset value is calculated at a 10% pitch, and a stabilization control preset table is generated. The generated stabilization control preset table is transmitted to the stabilization control execution means 10-9 and temporarily stored. These stabilization control preset values are updated at the timing when the tidal current calculation is performed, and the latest values when a system separation accident occurs are actually used.

  The system separation detection means 10-8 is a means for detecting system separation from the open / closed state of the circuit breaker 3A of the interconnection line 2. In the system separation detection means 10-8, for example, when the circuit breaker 3A of the interconnection line 2 in FIG. 2 is cut off and the system separation occurs, the auxiliary contact signal indicating the open / closed state of the circuit breaker 3A (the state of the circuit breaker 3A) Signal) through the input / output cable 7A. If the interconnection line 2 is received by two parallel lines, the system separation detection means 10-8 takes in signals for two lines, and the breaker 3A of the interconnection line 2 is cut off for both lines. Is detected by the logic circuit, the occurrence of system separation is detected, and a system separation signal indicating this is output as online system information. The system separation signal is transmitted to the stabilization control execution means 10-9 via the online data input / output means 10-4.

  The stabilization control execution means 10-9 selects a stabilization control preset value corresponding to the remaining voltage Vp at this time from the stabilization control preset table using the system separation signal of the system separation detection means 10-8 as a trigger, The stabilization control process is executed. When the system separation signal is transmitted from the system separation detection unit 10-8 to the stabilization control execution unit 10-9, the stabilization control execution unit 10-9 reads the stabilization control preset table stored therein primarily. Then, a stabilization control preset value corresponding to the actual residual voltage Vp is selected. Since the selected stabilization control preset value includes the control target and the control amount, the stabilization control execution means 10-9 calculates the control amount for the control target based on the selected stabilization control preset value. An instructing stabilization control command signal can be output. That is, in the case of load cutoff control, a cutoff signal is output to the load equipment 9 (to be blocked) included in the selected stabilization control preset value. In the case of power control, a stop signal is output to the generator 8 (to be controlled) included in the selected stabilization control preset value. In the case of phase control, a closing signal or a cutoff signal is output to the phase adjusting equipment 11 (to be controlled) included in the selected stabilization control preset value.

  The stabilization process output means 10-10 outputs the stabilization control command signal selected by the stabilization control execution means 10-9 to each control device. For example, if the stabilization control command signal indicates the load cutoff control, the stabilization processing output means 10-10 receives the stabilization control command signal indicating the load cutoff control from the system stabilizing device 10 in a stable manner. Is output to each circuit breaker 3E indicated by the control command signal through the input / output cable 7C. At this time, it is necessary to output a stabilization control command signal after conversion to a signal that matches the specifications of each circuit breaker 3E. For this reason, the stabilization processing output means 10-10 converts the stabilization control command signal selected by the stabilization control execution means 10-9 into a signal that matches the specification of the circuit breaker 3E that is the output destination. Output. The stabilization processing output means 10-10 may be constituted by an auxiliary relay, for example.

(flowchart)
FIG. 3 is a diagram for explaining an example of the flow of the processing operation of the system stabilization control executed by each means of the system stabilization apparatus 10 in the present embodiment.
The system stabilizing device 10 (online data input / output means 10-4) is used for the tidal current calculation "the interconnection line 2, the generator group (for example, the generator 8) in the separated system, and the control target in the separated system. Data of online system information such as a power flow value of a load group (for example, load facilities 9a to 9c), an open / close state of a circuit breaker (for example, circuit breakers 3A to 3E), and a bus voltage in a separated system is sampled (step S1).
Next, the tidal current calculation execution means 10-5 calculates the tidal current after the system separation occurs based on this sampling data (for example, the active power and reactive power of the whole separated system, and the control target in the separated system ( For example, individual active power and reactive power of the load facilities 9a to 9c) are performed (step S2). At this time, when there are a generator group and a load group that are determined to be shut off in advance together with system separation, the tidal current calculation execution unit 10-5 performs tidal current calculation in a state where each is shut off. From the result of the power flow calculation, the power flow calculation execution means 10-5 determines whether the frequency and voltage in the separated system after the system separation are within the operation allowable values (step S3).

As a result of this determination, when it is determined that the frequency and voltage in the separated system after the system separation are within the allowable operating values, the system stabilizing device (the power flow calculation executing means 10-5) selects no control. (Step S21), the process proceeds to Step S11 described later.
On the other hand, when it is determined that the frequency and voltage in the separated system after the system separation are not within the operation allowable values, the tidal current calculation execution means 10-5 determines the load from the unbalanced amount of the active power P in the separated system. At least one of a control amount (load cutoff amount) and a power control amount (power generation cutoff amount or power generation output suppression amount) is calculated (step S4).
Next, the tidal current calculation execution means 10-5 performs tidal current calculation after controlling the active power P in the separated system for the purpose of stabilizing the frequency (step S5). Then, the power flow calculation executing means 10-5 determines whether or not the voltage and frequency in the separated system after the system separation are within the operation allowable value from the result of the power flow calculation (step S6).

As a result of this determination, when it is determined that the voltage in the separated system after the system separation is within the operation allowable value, the system stabilizing device 10 (the power flow calculation executing means 10-5) performs the frequency stabilization control. Select (step S22), the process proceeds to step S11 to be described later.
On the other hand, when it is determined that the voltage in the separated system after the system separation is not an allowable operation value, the power flow calculation executing means 10-5 requests the phase adjustment control amount from the unbalance amount of the reactive power Q in the separated system. A value is calculated (step S7).

Next, the power flow calculation execution unit 10-5 determines whether the calculated required value of the phase adjustment control amount (control request value of the phase adjustment control) is within the control range of the phase adjustment equipment 11 (step S8). . As a result of this determination, if it is determined that the required value of the phase adjustment control amount is within the control range of the phase adjusting equipment 11, the system stabilizing device 10 (the power flow calculation executing means 10-5) stabilizes the frequency and voltage. Control is selected (step S23), and the process proceeds to step S11 described later.
On the other hand, when it is determined that the required value of the phase adjustment control amount is not within the control range of the phase adjustment equipment 11, the tidal current calculation execution means 10-5 balances the reactive power Q corresponding to the insufficient amount of phase adjustment control. The load control amount (load cutoff amount) is additionally corrected so as to be controlled (step S9). That is, the power flow calculation execution unit 10-5 adds a control amount corresponding to the shortage amount of the phase control to the load control amount (load cutoff amount).
Next, the tidal current calculation execution means 10-5 performs tidal current calculation when both the phase control and the load control that compensates for the shortage of the phase control for the purpose of voltage stabilization. The process proceeds to step S10) and step S11.

  In step S11, the power flow calculation execution unit 10-5 sets the reference stabilization control amount (load control amount, power supply control amount, phase adjustment control amount) of the control mode finally selected in the above-described processing. . This reference stabilization control amount means a stabilization control amount that is necessary at the time of a system separation accident that is not accompanied by a voltage drop.

When setting the reference stabilization control amount, the tidal current calculation execution means 10-5 determines the tidal current (for example, active power / reactive power in the entire separated system and in the separated system from the result of the tidal current calculation based on the online system information. The data indicating the balance of the individual active power and reactive power) to be controlled is derived, and the reference stabilization control amount is set using this data.
If no control is selected in step S21, the reference stabilization control amount is 0 (zero). When the frequency and voltage stabilization control is selected in step S23, the reference stabilization control amount is set by further using the phase adjustment control amount calculated in step S7. Further, when the load control amount (load cutoff amount) is additionally corrected in step S9, the phase control amount calculated in step S7 and the additionally corrected load control amount (load cutoff amount) are further used. To set the reference stabilization control amount. By doing so, the reference stabilization control amount becomes as appropriate as possible.

  In addition, the transient stability analysis means 10-6 inputs the online system information and the input in advance at an arbitrary timing after the online system information data is sampled in the above-described step S1 until step S12 described later starts. Based on the transient characteristics data set in this way, the transient stability is calculated at regular intervals, and the reactive power transient fluctuation amount immediately before or immediately after system separation is corrected based on the calculated result. The coefficient Kv is calculated (step S31). As described above, the reactive power transient fluctuation correction coefficient Kv is a function having the residual voltage Vp as a parameter.

  Next, the system stabilization control preset table generation means 10-7 uses the residual voltage Vp immediately before the occurrence of the system separation in order to take into account the amount of transient reactive power fluctuation at the time of the system separation accident accompanied by the voltage drop. Using the correction coefficient Kv of reactive power transient fluctuation as a parameter, the reference stabilization control amount is corrected, and a stabilization control amount table is generated in which the corrected reference stabilization control amount is stored using the remaining voltage Vp as a parameter ( Step S12).

Next, the system stabilization control preset table generation means 10-7 stores the contents of the control (load control, power supply control and phase adjustment control) necessary in the case of a system isolation accident accompanied by a drop in the bus voltage in the isolated system. The control control preset table is generated. That is, the system stabilization control preset table generation unit 10-7 selects a control target according to a preset priority order, and the system control accident table ("system separation accident without voltage drop calculated for each remaining voltage Vp"). The control amount for the selected control object is obtained for each residual voltage Vp from the control amount data “) necessary for the stabilization control at the time”. Then, a “stabilized control preset table for load control, power supply control, and phase adjustment control” in which the stabilization control preset value including the control object and the control amount is stored as a parameter is generated (step) S13).
Next, the system separation detection means 10-8 determines the presence or absence of a system separation accident from the open / closed state of the circuit breaker 3A of the interconnection line 2 (step S14). If the result of this determination is that a system separation accident has not occurred, the process returns to step S1, and the above control loop is repeated to update the stabilization control preset table in the latest system state.
On the other hand, when a system separation accident occurs, the stabilization control execution means 10-9 selects a stabilization control preset value corresponding to the remaining voltage Vp of the bus 1a immediately before or after the system separation accident occurs. Then, a stabilization control command signal based on the selected stabilization control preset value is transmitted to each control device through the stabilization process output means 10-10, and the stabilization control process is performed (step S15).

(Specific signal processing)
Next, a reactive power transient fluctuation correction coefficient using the remaining voltage Vp immediately before (or immediately after) the occurrence of system separation as a parameter, in order to take into account the amount of transient reactive power fluctuation at the time of a system separation accident involving a voltage drop Kv will be described.

  FIG. 4 is an example showing a temporal change of the bus voltage V of the main bus 1a in the separated system when a system separation accident with a voltage drop occurs in the main system and the system is separated. In this example, since a short-circuit accident has occurred in the main system, a sudden voltage drop occurs in the main bus 1a in the separation system, and the bus voltage V Shows the process of returning. The bus voltage V is the lowest voltage immediately before (or immediately after) the occurrence of the fault point or system separation, and the balance of the reactive power Q of the system changes transiently depending on the magnitude of the residual voltage Vp.

  FIG. 5 is an example showing the relationship between the residual voltage Vp and various characteristics (active power P, reactive power Q, power factor Pf, current I) of a load group having constant power load characteristics. The effective power P of the terminal load facilities 9a to 9c is substantially constant without being relatively affected by the voltage drop. However, since the current value increases as the bus voltage V decreases (remaining voltage Vp decreases), the consumption of reactive power Q in the line reactance increases. For this reason, the reactive power Q seen from the power source side is an example of increasing rapidly as the residual voltage Vp decreases.

  Power generation including dynamic characteristics of load groups having such constant power characteristics, line reactance between load groups and generator groups (step-up transformers in power plants and distribution transformers in substations), and reactive power Q limiting control operations Example of correction coefficient Kv for reactive power transient fluctuation using residual voltage Vp as a parameter, calculated by performing transient stability calculation in consideration of the dynamic characteristics of the machine group and the dynamic characteristics of the phase adjusting equipment at regular intervals. Is shown in FIG. Kv is a function of the residual voltage Vp and is expressed by the following equation (1).

  Kv = f (Vp) (1)

The reactive power transient fluctuation correction coefficient Kv varies depending on the characteristics of individual devices constituting the system, but can be approximated by the following approximate expression (2), for example.
Kv = 1 + (1-Vp) α (2)
Here, α is a variable of the approximate expression, and the unit of Vp is a unity value [pu]. Note that the value of α can be approximated within a range of 1.5 to 2, for example.

  The system stabilization control preset table generation means 10-7 corrects the reference stabilization control amount using the reactive power transient fluctuation correction coefficient Kv. For example, the system stabilization control preset table generation unit 10-7 corrects the consumption amount of the reactive power Q of the load group viewed from the power source after the system separation, and the load control amount from the unbalanced amount of the reactive power Q after the correction. Correct. Since the balance of the active power P is also unbalanced due to the correction of the load control amount, the system stabilization control preset table generating means 10-7 simultaneously corrects the power control amount from the unbalance amount of the active power P. Then, a final stabilization control amount table is generated.

  In the system stabilization control flow of FIG. 3, the transient stability calculation for calculating the correction coefficient Kv of the reactive power transient fluctuation is performed for each control cycle. When the change of the load characteristic is small, it is not always necessary to carry out every control cycle. For example, there is no problem in accuracy even if it is carried out in units of minutes or hours. Further, the processing for calculating the correction coefficient Kv of the reactive power transient fluctuation does not necessarily have to be performed by the system stabilizing device 10, but is obtained by offline analysis, and the system stabilizing device 10 communicates and acquires the result. It may be realized. Further, a discrete value set for each range of the residual voltage Vp may be used as the reactive power transient fluctuation correction coefficient Kv.

<Second Embodiment>
An example of a specific system configuration for realizing the system stabilization apparatus of the present invention in the system stabilization apparatus 10 shown in FIG. 1 will be described.
In this embodiment, the system configuration detection means 10-1 is an auxiliary relay, the power flow information detection means 10-2 is a transducer, the system voltage detection means 10-3 is a high response transducer or voltage relay, and the system separation detection means 10-8 is an auxiliary. The relay, relay circuit, and stabilization processing output means 10-10 are constituted by an auxiliary relay circuit. If each installation place is the same place, each is stored in the same interface board. On the other hand, if each installation location is different, each is housed in an independent interface board, and signals are exchanged with the online data input / output means 10-4 using an interface cable or a communication cable using a remote I / O board. To do. Online data input / output means 10-4, power flow calculation execution means 10-5, system stabilization control preset table generation means 10-7, and stabilization control execution means 10-9 correspond to the main controller of the system stabilization apparatus 10, It is composed of the same digital control device (generally called DCS device) or programming controller (generally called PLC). Each function is constructed by software embedded in the master controller. The transient stability analysis means 10-6 can be incorporated in the above master controller, but in order to prevent a reduction in calculation processing speed in the master controller, it is incorporated in an independent industrial personal computer. It is desirable to have a configuration for transmitting data by communication with the control device.

  The configuration of the system stabilizing device 10 described above is an example, and it is obvious that elements, devices, and the like used for the configuration may be configured by alternative parts and devices well known to those skilled in the art. In addition, in the signal processing and data processing performed by each means, whether to use an analog signal or a digital signal may be properly used depending on the installation environment.

  If the system stabilizing device 10 is configured as described above, the reactive power Q can be supplied by instantaneously compensating for the transient unbalance of the reactive power Q after the system separation, even in a system separation accident involving a voltage drop. The failure of the independent operation of the power generation facility (generator 8) in the separated system due to shortage or the like can be avoided, and stable power supply can be performed even after the system is separated.

Each embodiment of the present invention described above can be realized by a computer executing a program. Further, a means for supplying the program to the computer, for example, a computer-readable recording medium such as a CD-ROM recording such a program, or a transmission medium for transmitting such a program may be applied as an embodiment of the present invention. it can. A program product such as a computer-readable recording medium in which the program is recorded can also be applied as an embodiment of the present invention. The above programs, computer-readable recording media, transmission media, and program products are included in the scope of the present invention.
The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

1 shows an embodiment of the present invention and is a configuration diagram of a system stabilizing device. FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of an electric power system (system | strain structure) which shows embodiment of this invention and incorporates it. It is a flowchart which shows embodiment of this invention and demonstrates the processing operation of system | strain stabilization control. It is a figure which showed the embodiment of this invention and demonstrated the aspect of the residual voltage when the system isolation | separation accident with a voltage drop occurred. It is a figure showing an example of various characteristics to a residual voltage of a load group which shows an embodiment of the invention and has a constant power characteristic. It is a figure showing an embodiment of the present invention and showing an example of a correction coefficient of reactive power transient fluctuation. It is a block diagram of the conventional system | strain stabilization apparatus.

Explanation of symbols

1 Main system substation bus 1A Separation system substation bus 1B Power station bus 1C Load facility bus 2 Transmission lines 2B to 2E for interconnection with the main system Transmission lines 3A to 3D Breaker 4A in the separation system -4F sensor (current transformer)
5A-5C sensor (transformer)
6A to 6F Input cables 7A to 7D Input / output cable 8 Generators 9a to 9c Load 10 System stabilizing device 11 Phase adjusting equipment 12B, 12C Transformer 10-1 System configuration detecting means 10-2 Power flow information detecting means 10-3 System Voltage detection means 10-4 Online data input / output means 10-5 Power flow calculation execution means 10-6 Transient stability analysis means 10-7 System stabilization control preset table generation means 10-8 System separation detection means 10-9 Stabilization control Execution means 10-10 Stabilization processing output means

Claims (4)

Upon occurrence of a system separation accident in the power system, a first line for detecting the current of each bus line in the separated system, the circuit breaker, and each transmission line in the separated system connected to the main system via the interconnection line Stabilization of single operation by the generator in the separation system in the separation system including the sensor, the second sensor for detecting the voltage of the bus in the separation system, the generator, the load facility, and the phase adjusting facility A system stabilizing device for
Based on a signal indicating the open / close state from the circuit breaker, system configuration detection means for detecting the system configuration in the separated system at a predetermined cycle;
Based on the current signal from the first sensor and the voltage signal from the second sensor, for each facility including the transmission line, load facility, generator, and phase adjusting facility in the separation system, the voltage, frequency, Tidal current information detecting means for detecting tidal current information including current, active power, and reactive power;
Based on the voltage signal from the second sensor, the bus voltage in the separation system is detected when the voltage of the bus in the separation system is detected at a speed higher than the predetermined period and the system separation accident occurs. System voltage detection means for detecting a transient fluctuation value of the voltage of
Based on online system information including the system configuration and the power flow information, transient characteristic data of the load equipment, voltage characteristic data of the phase adjusting equipment, and transient characteristic data including overexcitation protection operation characteristics of the generator. In addition, a transient stability analysis means for calculating the transient stability and calculating a correction coefficient for the reactive power transient variation immediately after the occurrence of the system separation accident based on the result of the executed calculation;
The control object in the separated system when a system separation accident occurs with a decrease in the voltage of the bus in the separated system, with the residual voltage of the bus in the separated system as a parameter immediately before the occurrence of the system separated accident A stabilization control preset table storing a stabilization control preset value indicating a control amount for stabilizing control, a result of power flow calculation based on the online system information, and a correction coefficient for the reactive power transient fluctuation amount. A system stabilization control preset table generating means to be generated using,
The stabilization from the stabilization control preset table based on the transient fluctuation value of the voltage of the bus in the separation system, triggered by a system separation signal indicating the system separation detected from the open / close state of the circuit breaker of the interconnection line Stabilization control execution means for selecting a control preset value and executing the stabilization process instantaneously;
A stabilization process output means for outputting a stabilization control command based on the selected stabilization control preset value to a device to be controlled,
Compensation for reactive power imbalance when a system separation accident involving a transient voltage drop of the bus in the separated system occurs, and the islanding operation by the generator in the separated system after the system separation accident occurs A system stabilizing device characterized by stabilizing the system. Upon occurrence of a system separation accident in the power system, a first line for detecting a current of each bus line in the separation system, the circuit breaker, and each transmission line in the separation system connected to the main system via the interconnection line Stabilization of single operation by the generator in the separation system in the separation system including the sensor, the second sensor for detecting the voltage of the bus in the separation system, the generator, the load facility, and the phase adjusting facility A system stabilization method for
Dynamic characteristics of the load group including the load facility having constant power characteristics, line reactance between the load group and the generator group, dynamic characteristics of the generator group including a reactive power limit control operation, Reactive power transient fluctuation to calculate the transient fluctuation amount of the reactive power when the system separation accident occurs based on the calculated transient stability considering the dynamic characteristics of the phased equipment Generating an amount of correction coefficient as a parameter of a residual voltage of a bus in the separated system immediately before the occurrence of the system separation accident;
A stabilization control amount calculated from data relating to tidal current balance obtained from tidal current calculation based on online system information including tidal current information about the system configuration in the segregated system and equipment in the segregated system, The reference stabilization control amount required at the time of system separation accident without voltage drop is corrected with the correction coefficient of the reactive power transient fluctuation amount, and the corrected reference stabilization control amount is immediately before the occurrence of the system separation accident. Generating a stabilization control amount table storing the residual voltage of the bus in the separation system as a parameter;
Control for selecting a control target in the separated system according to a preset priority, and stabilizing control of the selected control target when a system separation accident accompanied by a drop in the voltage of the bus in the separated system occurs The stabilization control preset table in which the stabilization control preset value indicating the amount is stored with the remaining voltage of the bus in the separated system immediately before the occurrence of the system separation accident as a parameter is used as the stabilization control amount table. Generating steps,
When the system separation accident occurs, the stabilization control preset value is selected from the stabilization control preset table based on the transient fluctuation value of the voltage of the bus in the separation system, and the stabilization control is instantaneously performed. Performing the steps of:
Compensation for reactive power imbalance when a system separation accident involving a transient voltage drop of the bus in the separated system occurs, and the islanding operation by the generator in the separated system after the system separation accident occurs The system stabilization method characterized by stabilizing. Determining whether a control request value for phase control in the phase adjusting equipment is within a control range of the phase adjusting equipment; and
When it is determined that the control request value of the phase control is not within the control range of the phase control equipment, the load control amount is set to control the reactive power balance amount corresponding to the shortage amount of the phase control. The system stabilization method according to claim 2, further comprising a step of performing additional correction to set the reference stabilization control amount to an appropriate value. A system stabilization device for stabilizing an isolated operation by a generator in a separated system separated from a main system by the occurrence of a system separation accident in the power system,
Tidal current calculation execution means for performing tidal current calculation using the tidal current information in the equipment in the separated system and the configuration information in the separated system;
Reactive power in the separated system when the voltage of the bus in the separated system is reduced due to the system separation accident is obtained by calculation of transient stability, and the system separation accident occurs using the obtained reactive power. A transient stability analysis means for calculating a correction coefficient for estimating the transient fluctuation amount of the reactive power at the time,
The stabilization control amount obtained using the result of the power flow calculation, which is necessary for a system separation accident not accompanied by a voltage drop, is corrected using the correction coefficient, and is corrected. A stabilization control amount table generating means for generating a stabilization control amount table in which a control voltage is stored as a parameter with a residual voltage of a bus in the separation system accompanying the occurrence of the system separation accident;
A stability indicating a control amount for stabilizing the selected control target when a control target in the isolated system is selected according to a predetermined priority order and a system separation accident accompanied by a decrease in the voltage of the bus occurs. Stabilization control for generating a stabilization control preset table using the stabilization control amount table as a parameter for storing a control control preset value as a parameter of a residual voltage of a bus in the separation system when the system separation accident occurs Preset table generation means;
When the system separation accident occurs, the stabilization control preset value is selected based on a transient fluctuation value of the voltage of the bus in the separation system, and the control target is controlled according to the selected stabilization control preset value. A system stabilization apparatus comprising: stabilization control execution means.

Images