JP5399284B2 - Voltage stabilization device and voltage stabilization method - Google Patents

Description

  The present invention relates to a power stabilization device and a voltage stabilization method.

  For example, when a route disconnection accident or the like occurs in a power transmission line of the power system, the effective power of the power transmission line route from the generator to the load excluding the transmission line that has been disconnected is rapidly increased. As a result, the voltage of the bus connected to the load may decrease, and the voltage stability of the bus may not be maintained (see, for example, Patent Document 1).

  Therefore, when an accident or the like occurs, for example, the load is cut off in order to maintain the voltage stability of the bus.

Japanese Patent Laid-Open No. 02-206329

However, if the load is interrupted in order to maintain voltage stability, power is not supplied to the interrupted load, resulting in a power failure.
The present invention has been made in view of the above problems, and an object thereof is to provide a voltage stabilization device capable of maintaining voltage stability without interrupting a load.

In order to achieve the above object, a voltage stabilizer according to one aspect of the present invention includes a detector that detects an accident position of a transmission line disposed in a power system, and a plurality of transformers connected to the transmission line. A phase adjuster disposed on each of the buses, such as a station, for controlling the reactive power supplied to each of the buses, and when the detector detects an accident position of the power transmission line, the power system including the bus A plurality of generators for supplying power to the transmission line such that the voltage of the bus is higher than the voltage level when the active power of the load connected to the bus is maximized, in order to maintain the voltage stability of A control device that controls the shutoff or turning on of at least one of the phase adjusters, and the control device prioritizes the shutoff or turning on of the phase adjuster over the shutoff of the generator. It is characterized by.

  According to the present invention, it is possible to provide a voltage stabilizing device capable of maintaining voltage stability without interrupting a load.

It is a figure which shows the structural example of the voltage stabilization apparatus 10 which is one Embodiment of this invention. It is the figure which represented the system | strain of the power plant A and the substation B by the 1 machine 1 load model. It is an example of the PV curve of the load 220 (bus 151). It is an example of the PV curve in the load 220 (bus 151) when the inductor 210 increases. It is a figure which shows the 1 machine 1 load model containing the capacitor | condenser 230. FIG. It is an example of the PV curve in the load 220 (bus | bulb 151) when the capacitor | condenser 230 is thrown in. 5 is a flowchart showing an example of processing of a computing device 72. 3 is a flowchart for explaining the operation of the voltage stabilizing device 10;

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

  FIG. 1 is a diagram illustrating a configuration example of a voltage stabilizing device 10 according to an embodiment of the present invention. The power stabilization device 10 is provided in a power system including the power plant A and the substations B to D, and includes control devices 20 to 23, power capacitors (SC: Shunt Capacitors, 30 to 32), minutes. A road reactor (ShR: Shunt Reactor) 40 to 42 and an overall control device 50 are included.

  First, an outline of a power system in which the voltage stabilization device 10 is provided will be described. In the power system shown in FIG. 1, the electric power generated at the power plant A is transmitted to the substations B to D and the infinite bus 170.

  The power plant A and the substation B are connected by a power transmission line 100, and the power plant A and the substation D are connected by a power transmission line 101. Substation B and substation C are connected by power transmission line 102, and substation C and substation D are connected by power transmission line 103. Moreover, the circuit breaker (not shown) for interrupting | transmitting power transmission is provided in each both ends of the power transmission lines 100-103. Here, for example, the substation D and the power plant A are disconnected from each other. For this reason, the electric power generated at the power plant A is transmitted through a route of the power plant A, the substation B, the substation C, and the substation D. Note that each of the power transmission lines 100 to 103 includes, for example, three power transmission lines, but for the sake of convenience, it is illustrated with one line in FIG.

  The control device 20 controls on / off of the generator 110 of the power plant A based on an instruction from the overall control device 50. Electric power from the generators 110 and 111 is transmitted to the transmission lines 100 and 101 via the bus 150.

  The control device 21 controls turning on and off of the power capacitor 30, the branch reactor 40, and the transformer 170 connected to the bus 151 of the substation B based on an instruction from the overall control device 50. The bus 151 is connected between the power transmission line 100 and the power transmission line 102. The transformer 170 connected to the bus 151 transforms the voltage of the bus 151 and supplies it to various devices (not shown).

  The control device 22 controls the turning on and off of the power capacitor 31, the branch reactor 41, and the transformer 171 connected to the bus 152 of the substation C based on an instruction from the overall control device 50. The bus 152 is connected between the power transmission line 102 and the power transmission line 103. The transformer 171 connected to the bus 152 transforms the voltage of the bus 152 and supplies it to various devices (not shown).

  The control device 23 controls turning on and off of the power capacitor 32, the branch reactor 42, and the transformer 172 connected to the bus 153 of the substation D based on an instruction from the overall control device 50. The bus 153 is connected between the power transmission line 101 and the power transmission line 103. The transformer 172 connected to the bus 153 transforms the voltage of the bus 153 and supplies it to various devices (not shown). Bus 153 is linked to infinite bus 170.

  The power capacitor (SC) 30 is a phase adjuster that controls the reactive power of the bus 151 by being turned on or off. Although details will be described later, when the power capacitor 30 is turned on, the voltage of the bus 151 increases. Similarly to the power capacitor 30, each of the power capacitors 31 and 32 is a phase adjuster that controls the reactive power of the buses 152 and 153.

  The shunt reactor (ShR) 40 is a phase adjuster that controls the reactive power of the bus 151 by being turned on or off. Although details will be described later, when the branch reactor 40 is shut off, the voltage of the bus 151 increases. Each of the branch reactors 41 and 42 is a phase adjuster that controls the reactive power of the buses 152 and 153 in the same manner as the branch reactor 40.

  The overall control device 50 is provided at, for example, a power supply command station (not shown) of the power system, and is based on the system information of the input power system and the state of the protection relay (not shown) provided on the transmission lines 100 to 103. Then, the control devices 20 to 23 are controlled. The overall control device 50 includes an accident detection device 70, a system information collection device 71, a calculation device 72, a storage device 73, and a control device 74.

  The accident detection device 70 (detector) detects whether an accident has occurred in the power transmission lines 100 to 103 and the position of the accident based on the state of a protection relay (not shown) provided in the power transmission lines 100 to 103. . Further, when the accident detection device 70 detects that an accident has occurred, the accident detection device 70 generates accident information indicating the accident position and the aspect of the accident, and transmits the accident information to the control device 74.

  The system information collection device 71 is configured to output the voltages of the buses 150 to 153 and the transmission lines 100 to 103 based on outputs from, for example, current transformers for measurement and instrument transformers (not shown) distributed in the power system. , Operation information such as active power and reactive power of the buses 151 to 153 is collected. Further, the system information collecting device 71 collects device information such as whether the generators 110 and 111, the power capacitors 30 to 32, the branch reactors 40 to 42, and the transformers 170 to 172 are turned on or off.

  Based on the above-described system information (operation information and equipment information) collected by the system information collection device 71, the arithmetic device 72 is capable of voltage stability of the buses 151 to 153 when an accident occurs in the transmission lines 100 to 103. The information regarding the generators 110 and 111 to be controlled, the power capacitors 30 to 32, the branch reactors 40 to 42, and the transformers 170 to 171 is calculated. Specifically, the computing device 72 calculates control information, which is information regarding the calculated device to be controlled, in a shorter cycle than when the load connected to the transformer 170 or the like fluctuates. Then, the arithmetic device 72 sequentially stores and updates the control information calculated periodically in the storage circuit 73. Details of the voltage stability and the calculation device 72 will be described later.

  The storage device 73 stores the control information described above. Based on the accident information and the control information, the control device 74 controls the control devices 20 to 23 so that the voltage stability of the buses 151 to 153 is maintained.

== About voltage stability ==
First, voltage stability will be described by taking the bus 151 of the substation B as an example. FIG. 2 is a diagram showing a system of the power plant A and the substation B by a general one-machine one-load model. Here, it is assumed that the power capacitor 30 and the branch reactor 40 are both shut off, for example. In FIG. 2, the power source 200 corresponds to the generators 110 and 111, the inductor 210 corresponds to the power transmission line 100, and the load 220 corresponds to the transformer 170 and devices connected to the transformer 170. Further, assuming that the terminal voltage of the load 220, that is, the voltage of the bus 151 is the voltage Vr, and the active power of the load 220 is P, a PV curve showing the relationship between the voltage Vr and the active power P is as shown in FIG. . As shown in FIG. 3, when the load 220 is interrupted, for example, and the impedance is infinite, the current flowing through the load 220 is zero and the active power P is zero. At this time, the voltage Vr becomes maximum because no voltage drop occurs. When the load 220 is turned on and the impedance drops from infinity, current starts to flow through the load 220. For this reason, the active power P increases and the voltage Vr decreases. That is, an increase in the load 220 means a decrease in the impedance of the load 220.

  When the impedance of the load 220 is zero, for example, the voltage Vr of the load 220 is zero, so the active power P is also zero. Therefore, in the PV curve shown in FIG. 3, there is a point where the active power P of the load 220 is maximized. In a region where the voltage Vr is higher than the voltage at which the effective power P is maximum, the effective power P supplied to the load can be increased while the voltage Vr decreases as the load 220 increases. However, in a region where the voltage Vr is lower than the voltage at which the effective power P is maximum, the voltage Vr decreases as the load 220 increases, and the effective power P supplied to the load also decreases. The effective power P originally required cannot be supplied. Therefore, a region higher than the voltage at the point where the active power P is maximum is a stable region where the voltage Vr is stable, and a region lower than the voltage where the active power P is maximum is an unstable region where the voltage Vr is not stable. . That is, the voltage at the point where the active power P is maximum is the stability limit voltage, and the maximum value of the active power P is the stability limit power. In the present embodiment, the voltage stability being maintained means that, for example, the voltage at the operating point is in a range higher than the stability limit voltage by a predetermined level or more.

  By the way, for example, if one of the three lines of the transmission line 100 in the system model shown in FIG. 1 is disconnected due to an accident or the like, the transmission line 100 is equivalent in the system model shown in FIG. This corresponds to an increase in the impedance of the inductor 210 simulated by the above. As a result, the phase of the power supplied from the power source 200 is delayed, and the PV curve changes from a dotted line in FIG. 4 to a solid line. Therefore, for example, even when the operating point exists in a sufficiently stable region before the accident, when the accident occurs, the PV curve after the accident approaches the unstable region. In such a case, for example, when the state of the load 220 changes, the operating point may immediately enter an unstable region and power transmission may become impossible.

  Further, for example, in the system model shown in FIG. 1, when the power capacitor 30 is turned on, the system model shown in FIG. 2 becomes as shown in FIG. In FIG. 5, the capacitor 230 corresponds to the power capacitor 30. Capacitor 230 is connected to inductor 210 to advance the phase of power supplied from power supply 200. Therefore, the PV curve when the power capacitor 30 is turned on is as shown by the solid line in FIG. Therefore, for example, when the power capacitor 30 is turned on, the operating point moves to a region where the voltage stability becomes higher. Here, the change of the PV curve when the power capacitor 30 is turned on has been described. However, when the branch reactance 40 is turned off, the generator 110 is turned on. When cut off from the state, the PV curve changes as in FIG. In addition, when the generator 110 is shut off from the state where it is turned on, the power supplied from the power source 200 via the inductor 210 is reduced, and therefore, in the PV curve, it is equivalent to the reduction of the active power P. is there. That is, when the power capacitor 30 is turned on, the branch reactance 40 is shut off, or the generator 110 is shut off, the voltage stability is improved.

  As described above, when an accident occurs in the transmission lines 100 to 103, the voltage stability of the buses 151 to 153 deteriorates. However, if the generator 110, the power capacitors 30 to 32, and the branch reactors 40 to 42 are controlled, the voltage will be reduced. Stability is improved. Therefore, for example, when an accident occurs in the power transmission lines 100 to 103, it is possible to prevent deterioration of the voltage stability of the buses 151 to 153 by controlling the appropriate power capacitor 30 and the like.

== An example of processing executed by the computing device 72 ==
In FIG. 7, for example, when an accident occurs in a predetermined one of the three power transmission lines in the power transmission line 100, the arithmetic device 72 calculates control information for maintaining the voltage stability of the buses 151 to 153. It is an example of the process to perform. The computing device 72 selects devices such as the power capacitor 30 to be controlled in advance before a predetermined accident occurs by executing each process of the flowchart shown in FIG. Note that the computing device 72 is, for example, a computer, and performs each process of FIG. 7 by executing a program stored in the memory of the computer. FIG. 7 shows processing when an accident occurs in a predetermined one of the power transmission lines 100. The computing device 72 performs the same processing as that in FIG. It carries out also for each of the electric wires 101-103.

  First, the computing device 72 calculates a PV curve in the buses 151 to 153 when an assumed predetermined accident occurs based on the system information collected by the system information collecting device 71 (S100). Then, based on the calculated PV curve and the current operating point, the computing device 72 determines whether or not voltage stability can be maintained when an accident occurs (S101). Whether or not the voltage stability is maintained is determined based on, for example, whether or not the voltage at the current operating point is higher than the stability limit voltage by a predetermined level. If the voltage stability can be maintained (S101: YES), the computing device 72 stores information indicating that there is no need to change the current state of the device in the storage device 73 as control information (S106). . On the other hand, when the voltage stability cannot be maintained (S101: NO), that is, when the voltage stability of at least one of the buses 151 to 153 cannot be maintained, the arithmetic unit 72 includes the power capacitors 30 to 32, branching A PV curve when each of the reactances 40 to 42 is turned on or off is calculated for each bus (S102). In this embodiment, there are three power capacitors 30 to 32, three branch reactances 40 to 42, and six controllable phase adjusters. For this reason, the arithmetic unit 72 calculates 64 types of PV curves for each bus when each of the six phase adjusters is shut off and turned on. Then, the computing device 72 determines whether or not the voltage stability can be maintained for each bus based on the calculated 64 PV curves and the current operating point (S103). When the voltage stability can be maintained (S103: YES), that is, when all the voltage stability of the buses 151 to 153 can be maintained, the arithmetic device 72 stores information on the state of the device at that time as control information in the storage device 73. (S106). In the process 103, when there are a plurality of device states that can maintain the voltage stability, the arithmetic unit 72 selects one state that minimizes the number of devices to be changed from the current device state. Control information.

  On the other hand, if the voltage stability of the buses 151 to 153 cannot be maintained even if all of the 64 PV curves for which the current operating point has been calculated are applied (S103: NO), the arithmetic unit 72 causes the generator 110 to operate. A PV curve is calculated when the above six phase adjusters are controlled while shutting off (S104). That is, the arithmetic unit 72 calculates 64 PV curves for each of the buses 151 to 153 in the process 104 in the state where the generator 110 is shut off, as in the process 102. Then, the computing device 72 determines whether or not the voltage stability can be maintained based on the 64 PV curves for each bus newly calculated in the processing 104 and the current operating point (S105). . When there is a PV curve that can maintain the voltage stability among the 64 newly calculated PV curves (S105: YES), the arithmetic unit 72 uses the information on the state of the device at that time as control information. Is stored in the storage device 73 (S106). In the process 105 as well as the process 103, when there are a plurality of device states in which voltage stability can be maintained, the computing device 72 is in a state in which the number of devices to be changed is the smallest from the current device state. Is selected as control information. On the other hand, if the voltage stability of the buses 151 to 153 cannot be maintained even if the current operating point is applied to all of the 64 newly calculated PV curves (S105: NO), the arithmetic unit 72 Information instructing to shut off the transformers 171 to 173 connected to the buses 151 to 153 is stored in the storage device 73 as control information (S106). That is, in this embodiment, when the process 105 is “NO”, the load is cut off in order to maintain the voltage stability. Note that the computing device 72 of the present embodiment periodically executes the processing shown in FIG.

== Operation of Voltage Stabilizer 10 ==
Here, the operation of the voltage stabilizing device 10 will be described with reference to FIG. Here, it is assumed that control information corresponding to the accident position is stored in the storage device 73 in advance.

  First, the accident detection device 70 detects whether an accident has occurred in the power transmission lines 100 to 103 based on the state of a protection relay (not shown) (S200). When the accident detection device 70 detects the accident and the position of the accident (S200: YES), the accident information is output to the control device 74. The control device 74 reads control information corresponding to the accident position from the storage device 73 based on the accident information (S201). Then, the control device 74 controls the control devices 20 to 23 based on the read control information (S202). As a result, the generators 110 and 111, the power capacitors 30 to 32, the branch reactors 40 to 42, and the transformers 170 to 171 according to the control information are controlled, and the voltage stability is maintained.

  In the above, the voltage stabilization apparatus 10 of this embodiment was demonstrated. When the accident detection device 70 detects the accident position, the control devices 20 to 23 and 74 shut off the generator 110 and turn on the power capacitors 30 to 32 and the like so that the voltage of the buses 151 to 153 becomes higher than the stability limit voltage. To control. As described above, for example, when the branch reactance 40 is cut off, the voltage stability of the buses 151 to 153 is maintained. As a result, in this embodiment, the voltage stability of the buses 151 to 153 can be maintained without interrupting the transformers 170 to 172.

  In addition, when the accident detection device 70 detects the accident position, the control devices 20 to 23 and 74 of the present embodiment shut off the generator 110 so that the voltage of the buses 151 to 153 is increased by a predetermined level from the stability limit voltage. The power capacitors 30 to 32 are controlled to be turned on. For this reason, for example, even when the load connected to the transformers 170 to 172 fluctuates, the voltage of the buses 151 to 153 can be prevented from immediately moving to the unstable region.

  In addition, the storage device 73 of the voltage stabilization device 10 stores control information indicating the relationship between the accident position and the device to be controlled. Therefore, the control device 74 can acquire the control information of the storage device 73 as soon as an actual accident occurs, and can control the control devices 20 to 23 to maintain the voltage stability. That is, in the present embodiment, it is possible to execute the process for maintaining the voltage stability quickly in a short time.

  Moreover, the arithmetic unit 72 of this embodiment calculates control information based on the PV curve obtained by changing the accident position of the power transmission line 100 and the state of devices such as the power capacitors 30 to 32, for example. ing. As described above, the voltage stability of the buses 151 to 153 is determined based on the PV curve. Therefore, the voltage stability of the buses 151 to 153 can be reliably maintained by calculating and using the PV curve when the accident occurs as in the present embodiment.

  Generally, since the state of the load connected to the transformers 170 to 172 changes at any time, the operating points on the buses 151 to 153 also change. For this reason, in order to maintain voltage stability in the event of an accident, it is necessary to change the device to be controlled as the operating point changes. The arithmetic device 72 of this embodiment calculates control information for every predetermined period. For this reason, even if it is a case where the state of load changes, the apparatus required in order to maintain the voltage stability of bus-bus 151-153 can be calculated periodically.

  In the present embodiment, the control of the phase adjuster such as the power capacitor 30 is prioritized over the interruption of the generator 110. For this reason, voltage stability can be maintained while maintaining the power supply amount of the power system.

  Further, for example, as shown in FIG. 6, when the branch reactor to which the power capacitor 30 is inserted is cut off, the voltage stability is improved. For this reason, voltage stability can be easily improved by using a power capacitor or a branching reactor as a phase adjuster.

  Moreover, the voltage stability of the buses 151 to 153 can be maintained by using the voltage stabilization method.

  The above-described embodiment is intended to facilitate understanding of the present invention, and is not intended to limit the present invention. The present invention is changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

  The arithmetic unit 72 shuts off the generator 110 when the voltage stability of the buses 151 to 153 cannot be maintained even if all the 64 PV curves for which the current operating point is calculated are applied (S103: NO). However, the PV curve when the above six phase adjusters are controlled (S104) is not limited to this. For example, when the process 103 is “NO”, the arithmetic device 72 calculates the PV curve when the generator 110 is shut off instead of controlling the six phase adjusters, and calculates the calculated PV Based on the curve and the current operating point, it may be determined whether the voltage stability of the buses 151 to 153 can be maintained. In such a case, when the voltage stability can be maintained, the arithmetic device 72 stores information instructing the shutoff of the generator 110 in the storage device 73 as control information, and the bus 151 when the generator 110 is shut off. When the voltage stability of ˜153 cannot be maintained, the arithmetic unit 72 may execute the process 104.

DESCRIPTION OF SYMBOLS 10 Voltage stabilization apparatus 20-23,74 Control apparatus 30-32 Power capacitor 40-42 Branch reactance 50 General control apparatus 70 Accident detection apparatus 71 System information collection apparatus 72 Arithmetic apparatus 73 Storage apparatus 100-103 Transmission line 110,111 Generator 150-153 bus 170 Infinite bus 200 Power supply 210 Inductor 220 Load 230 Capacitor

Claims (7)

A detector for detecting an accident position of a transmission line arranged in the power system;
A phase adjuster that is disposed on each of buses such as a plurality of substations connected to the power transmission line, and controls reactive power supplied to each of the buses, and
When the detector detects the accident position of the transmission line, the active power of the load connected to the bus is maximized in order to maintain the voltage stability of the power system including the bus. A control device for controlling the shut-off or turning-on of at least any one of the plurality of generators and the phase adjuster for supplying power to the transmission line so that the voltage level is higher than
With
The control device prioritizes the shutoff or input of the phase adjuster over the shutoff of the generator,
A voltage stabilizer characterized by. The voltage stabilization device according to claim 1 ,
The control device includes:
When the detector detects the accident position of the transmission line, controlling the shutoff or turning on of the device so as to be higher by a predetermined level than the voltage level when the active power of the load is maximized,
A voltage stabilizer characterized by. The voltage stabilization device according to claim 1 or 2 , wherein
A storage device that stores in advance information indicating the relationship between the accident position of the power transmission line and the device to be shut off or turned on;
The control device includes:
When the detector detects the accident position of the power transmission line, referring to the information in the storage device, shutting off or turning on the device,
A voltage stabilizer characterized by. The voltage stabilization device according to claim 1 or 2 , wherein
A storage device;
Based on a curve indicating the relationship between the voltage of the bus and the active power obtained when the accident position of the power transmission line and the interruption or on-off of the device are changed, the accident position and the interruption or on-off of the power transmission line are performed. An arithmetic device that calculates information indicating the relationship with the device to be stored and stores the information in the storage device as control information;
Further comprising
The control device includes:
When the detector detects an accident position of the power transmission line, referring to the control information stored in the storage device, shutting off or turning on the device,
A voltage stabilizer characterized by. The voltage stabilization device according to claim 4 ,
The arithmetic unit is:
Calculating the information indicating the relationship between the accident position of the power transmission line and the device to be interrupted or turned on every predetermined cycle, and storing the calculated information in the storage device as the control information;
A voltage stabilizer characterized by. The voltage stabilization device according to any one of claims 1 to 5 ,
The phase adjuster is a power capacitor or a branching reactor,
The control device, when the detector detects an accident position of the power transmission line, to turn on the power capacitor or shut off the shunt reactor,
A voltage stabilizer characterized by. Detect the accident position of the transmission line installed in the power system,
When the detector detects the accident position of the transmission line, the active power of the load connected to the bus is maximized in order to maintain the voltage stability of the power system including the bus. Arranged at each of a plurality of generators for supplying power to the transmission line and a plurality of buses such as a plurality of substations connected to the transmission line so as to be higher than the voltage level at the time, and supplied to each of the bus lines Among the phase adjusters that control reactive power, controlling the shutoff or turning on of at least any one of the devices while giving priority to the shutoff or turning on of the phase shifter over the shutoff of the generator,
The voltage stabilization method characterized by the above-mentioned.

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