JPH06101901B2 - Power system simulation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a power system simulation method applied to a training device for maintaining and improving a system operation technique / skill of a control staff.

[Conventional technology]

FIG. 4 is a conceptual diagram of processing of a conventional power system simulation method. In the figure, 1 is a CRT device, 2 is an accident sequence file, and 3 is an SV-like variable data file. The transient stability calculation step is executed in the training preparation stage, and the frequency / power flow calculation step is executed in the training execution stage.

Next, the operation will be described.

First, in the training preparation stage, the trainer uses the CRT screen 1 to display the failure occurrence time in the power system, the failure point, the failure type, and the operation relays such as the main protection relay or the backup protection relay that are considered to operate due to these system failures ( Bus protection, transmission line protection, transformer protection relay, etc.)
And a circuit breaker CB that trips with its operation relay
Various data relating to and are set using the light pen 4. The set data is stored in the accident sequence file 2, and the data relating to each of the operation relays and the circuit breaker CB is also stored in the SV change data file 3.

Next, the operation of the step-out relay is judged, but it is difficult to set it correctly by the trainer, so the transient stability calculation program is executed using the accident sequence file 2 as input data (step), As the determination result, the state change of the operating SO relay and the trip CB is stored in the SV state change data file 3.

When the transient stability calculation reaches the cutoff time, the contents of the SV-like variable data file 3 are rearranged in chronological order according to an instruction from the trainer. This concludes the training preparation stage.

The SV state change data is the state change data of the trip breaker depending on the operation contents of the main protection / reserve protection relay and the system protection relay and the operation result.

Next, in the training execution stage, the power flow calculation and frequency calculation programs are executed (steps) while extracting the state changes of the operation relay and trip breaker CB from the SV state change data file 3 in chronological order (step), and the overload relay (OLR). ), A real-time simulation of the power system by simulating the operation of the frequency drop relay (UFR) or the voltage / reactive power control device.

Details of this real-time simulation will be described below with reference to the flowchart of FIG. The overall operation of this real-time simulation is to perform frequency calculation and tidal current calculation every T seconds, and frequency calculation is Δ
It is performed continuously for n (= T / ΔT) times in steps of T seconds.

That is, the frequency calculation is repeated n (= T / ΔT) times at intervals of ΔT seconds, the power flow calculation at that point is executed once, and all processing is performed in real time T seconds to realize a real-time simulation. . Note that, usually, the power flow calculation and the frequency calculation are shared by different computers to realize the real-time simulation.

For detailed operation, first, the SV state change data file 3 at that time
The trip CB data is extracted from the device, the presence or absence of the change in the switch condition is judged (step), and if there is a change, the system separation calculation is executed to judge the separated system, the admittance matrix of the system is corrected, and the separated system is separated. Calculate the system capacity and total inertial capacity of (step).

Subsequently, after the completion of the system separation calculation, the power flow calculation is executed (step). On the other hand, if it is determined that there is no change in the step, it is checked whether or not there is a discontinuous change in the active power of the bus bar due to load cutoff (step),
If there is no change, the system frequency calculation for each separated system is executed in the same way as the end of the power flow calculation (step), and then the operation of the frequency lowering relay and the frequency rising relay responding to the system frequency is simulated (step). , These processing n
Repeat (T / ΔT) times. If it is determined that there is a discontinuous change in the step, the process of the step is executed.

Next, when the above processing is repeated n times, the power flow calculation at that time is executed (step), and the operation simulation of the overload relay or the voltage / reactive power control device that responds to the system voltage, the power flow of the transmission line, etc. Is executed (step), and finally, real-time synchronization processing (delay) for achieving synchronization for one cycle T seconds is executed (step), and the simulation for T seconds is completed. Then, the simulation of the next cycle is started.

T seconds are usually about 3 to 5 seconds, and ΔT is about 0.25 seconds.

T seconds are determined from the information update cycle of the actual control center automation system, and a simulation that satisfies this performance is defined as a real-time simulation.

[Problems to be solved by the invention]

Since the conventional power system simulation is configured as described above, it is necessary to simulate the operation of the main protection / reserve protection relay in the form of trainer settings. , If the circuit breaker of the accident equipment is turned on, the system will again have a system failure, but since the trainer cannot predict these in advance at the training preparation stage, SV condition change data for the failure is not set, Therefore, although there is a failure in the system, the power system simulation method has a problem that the system is executed in the form of no failure, resulting in inconsistency, and subsequent training becomes meaningless. . In addition, there is a problem that the system parallel operation that requires the synchronization input cannot be performed because the phase angles of both bus bars cannot be calculated.

The present invention has been made to solve the above-mentioned problems, and automatically simulates the operation of the main protection / reserve protection relay in the event of a system failure and automatically determines the breaker trip. It is an object of the present invention to obtain a power system simulation method capable of simulating the movement of the power system in the same way as in the actual system even when the system failure occurs again due to an erroneous operation of the trainee and also in the system parallel operation.

[Means for solving problems]

The power system simulation method according to the present invention executes a program for transient stability calculation by using as input data a failure point related to a failure of the power system and a condition of a failure type, and uses the calculation result to perform a main protection / reserve protection relay and a system. Simulates the operation of the protection relay and the voltage / reactive power control device, and displays the operation information of these various protection relays and the voltage / reactive power control device and the status change of the trip breaker as the operation result.
In the power system simulation method that simulates the movement of the power system after the training preparation stage stored in the state change data file, in the training execution stage, the transient stability calculation is executed every calculation cycle, and the main protection / reserve protection relay is executed. The operation simulation of is executed if a system failure occurs during the calculation cycle, and the operation simulation of the system protection relay and the voltage / reactive power control device is executed in parallel with the transient stability calculation for each calculation cycle. In the transient stability calculation, the frequency / power flow calculation of the power system is executed every fixed calculation cycle, the initial value of the transient stability calculation is recalculated using the calculation result, and the calculation is repeated to accumulate the numerical integration error. This makes it possible to calculate transient stability over a long period of time.

[Action]

The simulation method of the power system in this invention is
By automatically processing the simulation of the operation of the main protection / reserve protection relay based on the transient stability calculation, the manual setting in the training preparation stage of the trainer becomes unnecessary, and it is based on the mistaken operation by the trainee during the training. , Training for re-faults and system parallel operation requiring synchronous input can be performed in the same way as for the actual system.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is a CRT device, 2 is an accident sequence file, and 3 is an SV state change data file, and the step of transient stability calculation and the step of power flow / frequency calculation are executed also in the simulation method of the present invention.

FIG. 2 is an explanatory diagram showing the presence / absence of a system fault, the operating conditions of transient stability calculation and power flow / frequency calculation.

FIG. 3 is a detailed flow chart of transient stability.

Next, the operation of the above embodiment will be specifically described with reference to the flowchart of FIG.

First, at the training preparation stage, the trainer uses the CRT screen 1
At, a failure occurrence time, a failure point, and a failure type in the power system are set using the light pen 4. The set data is stored in the accident sequence file 2. Next, the operation judgment of the main protection / reserve equipment protection relay is performed by executing the transient stability calculation program with the accident sequence file 2 as input data, and the operation result of the main protection / reserve equipment protection relay is cut off. The respective states of the container CB are stored in the SV state change data file 3 (step).

This transient stability calculation needs to be performed until the operation determination of the step-out relay is completed, but is performed until T seconds (normally 3 to 5 seconds) which is one cycle of the power flow / frequency calculation. Since the operation determination of the step-out relay is usually 1-2 seconds, the above-mentioned cutoff time is sufficient.

Next, at the training execution stage, as shown in Fig. 1, main protection and
Performs transient stability calculation including simulation of operation of backup protection relay and power flow / frequency calculation that is power system simulation in parallel Further, as shown in FIG. 2, from the start of the training execution stage to T seconds, the operation judgment of the main protection / reserve protection relay is
Since the transient stability calculation (step) at the training preparation stage is performed, the transient stability calculation is not executed, but the power flow calculation and the frequency calculation are executed (step).

In the subsequent simulation step, transient stability calculation is performed, and the tidal current / frequency calculation is processed every nT.

In addition, the transient stability calculation is processed according to the flow charts shown in FIGS. 3 (a) and 3 (b).
From the above, data of failure occurrence time, failure point, and failure type is extracted, and if there is a failure within T seconds after the time, the operation simulation of the main protection / reserve protection relay is simulated based on the transient stability calculation. And the frequency response relay and the operation of the power flow response relay and the voltage / reactive power control device are simulated, and the operation relay and the data of the trip breaker CB are added to the time, and the SV variation data file 3 is added. Remember.

In other words, instead of manually simulating the operation of the main protection / reserve protection relay and the shear breaker CB as in the past, the operation simulation of the main protection / reserve protection relay etc. is performed using the transient stability calculation result. Then, this is stored in the SV state change data file 3.

Next, the processing flow will be described with reference to FIGS. 3A and 3B. First, it is determined whether the power flow / frequency calculation is executed in the cycle (step), and if not, the process branches to step. .

On the other hand, when the power flow calculation is executed, the power flow calculation result one cycle before the current cycle is fetched (step).

Then, the initial values of the generator internal voltage and phase angle are calculated (step), and in order to treat the load as a constant impedance load, the load admittance is calculated from the bus voltage of the load, active power and reactive power (step). ).

Next, the admittance matrix of the positive phase, negative phase, or zero phase circuit is calculated according to the fault type (step). Next, it is judged whether or not there is a change in the connection state of the system (step), and if there is no change, the process branches to the circuit network calculation process.

On the other hand, if there is a change, it is subsequently determined whether or not a failure has occurred (step), and if there is no failure, the process proceeds to the determination processing of whether or not there is a failure removal. If there is a failure,
A fault equivalent impedance to be added to the positive-phase circuit according to the type of fault is calculated based on the admittance matrix of the negative-phase and zero-phase circuits (step).

Next, it is determined whether or not the fault has been removed (step), and if there is no fault, the process proceeds to change the admittance matrix, and if there is, a process of treating the fault impedance as infinite is performed (step). Subsequently, the admittance matrix of the positive-phase circuit is changed accordingly (step), and then the voltage and current of the circuit network are calculated (step).

Next, find the electrical output of the generator using the voltage and current obtained in the step (step), and further determine the internal phase angle of the generator. Solve for (step).

From the above, the voltage and current of the network and the internal phase angle of the generator can be obtained.
Operation simulation of backup protection relay (step-out relay, bus protection, transmission line protection relay, etc.) and system protection relay (eg UFR, O
The operation simulation of FR and OLR) and the control device (for example, voltage / reactive power control device) is performed (step). Then, by simulating the operation of the step, the presence or absence of the operation of the system protection relay or the control device is judged (step).
The process proceeds to the process of determining the calculation end time. The control device is a device such as a voltage / reactive power control device that operates using the power flow calculation result as input data.

On the other hand, when the system protection relay and the voltage / reactive power control device are operated, the breaker CB that trips due to the relay operation is selected and the data is stored in the SV-like variable data file 3 (step). Then, it is determined whether or not the calculation time has reached T seconds (step), the time when it has not reached T seconds is updated, and Δt is updated, and the processing from step to step is repeated (step). If the calculation time has ended, the distribution of active power and reactive power of each branch is obtained (step) and the calculation is ended.

For the transient stability calculation, a high-speed arithmetic processor such as an array processor is used to realize real-time simulation. If the number of numerical integration steps for transient stability calculation increases and the numerical calculation error increases, execute the tidal current calculation and frequency calculation before that.
The result is used to restart the transient stability calculation.

〔The invention's effect〕

As described above, according to the present invention, since the operation simulation of the main protection / reserve protection relay is executed based on the transient stability calculation, the breaker of the accident equipment is turned on by the wrong operation of the trainee during the training. Even if it does, it detects that a system fault has occurred and uses the transient stability calculation result,
Since the operation of the main protection / reserve protection relay is simulated, the movement of the system can be simulated in the same way as the actual system, and the effect of training can be increased.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a process of a power system simulation method according to an embodiment of the present invention, FIG. 2 is an operation explanatory diagram based on this conceptual diagram, and FIG. 3 is a detailed process flowchart of the transient stability calculation, FIG. 4 is a processing conceptual diagram of the conventional power system simulation method, and FIG. 5 is a processing flow diagram of the same power flow / frequency calculation. 1 is a CRT device, 2 is an accident sequence file, 3 is an SV change data file. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A program for transient stability calculation is executed by using as input data the condition of failure point and failure type related to power system failure, and the result of the calculation is used for main protection / reserve protection relay and system protection relay and voltage. After the training preparation stage, which simulates the operation of the reactive power control device and stores the operation information of these various protection relays and the voltage / reactive power control device and the state change of the trip breaker as the operation result in the SV change data file. In the power system simulation method for simulating the movement of the power system, the transient stability calculation is executed in each calculation cycle at the training execution stage, and the operation simulation of the main protection / reserve protection relay causes a system failure between calculation cycles. If there is, execute the system protection relay and voltage
The operation simulation of the reactive power control device is executed in parallel with the transient stability calculation for each calculation cycle, and the transient stability calculation executes the frequency / power flow calculation of the electric power system for every constant calculation cycle to obtain the calculation result. A power system simulation method characterized in that the initial value of the transient stability calculation is recalculated using the method and the accumulated integral of the numerical integration error is eliminated by re-executing it to enable the long-term transient stability calculation.