JPH06101900B2 - Power system simulation method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power system simulation system applied to a training device for maintaining and improving system operation techniques and skills of 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 data file, 3 is an SV-like variable data file, and such a simulation system will be described later. ,
In the training preparation stage, the transient stability calculation step is executed, and in the training execution stage, the frequency / power flow calculation step is executed. Here, the SV state change data is data indicating the state change of the operation relay and the circuit breaker, and specifically,
It is made up of data representing the changed state and the time when the change occurred.

Next, the operation will be described.

First, in the training preparation stage, the trainer shows on the CRT screen 1 a failure occurrence time in the power system, a failure point, a failure type, and an operation relay such as a main protection relay or a backup protection relay that is considered to operate due to these system failures, Various data related to the trip operation and the circuit breaker (CB) are set by the operation relay using a light pen. The set data is stored in the accident sequence data file 2, and the data relating to each of the operation relays and the circuit breaker (CB) is also stored in the SV-like variable data file 4.

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

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

Next, at the training execution stage, while extracting the state changes of the SV-like data file 3 from the SV-like data file 3 in chronological order,
Execute power flow calculation and frequency calculation program (step), and then overload relay, frequency drop relay or voltage
By simulating the operation of the reactive power control device, real-time simulation of the power system is performed. The details of this real-time simulation will be described below with reference to the flowchart of FIG. As the overall operation of this real-time simulation, the frequency calculation and the power flow calculation are performed every T seconds, and the frequency calculation is continuously performed n (= T / ΔT) times in steps of ΔT seconds.

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

The detailed operation is as follows: First, the SV-like data file 3 at that time.
From the SV-like data, determine whether there is a change in the switch state (step), and if there is a change, execute system separation calculation, determine the separated system, correct the system admittance matrix, and separate the system. Calculate the grid capacity and total inertial capacity of the grid (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 step, check whether there is a discontinuous change in the active power of the bus due to load or disconnection (step), and if there is no change, the same as the end of the power flow calculation. Then, the system frequency calculation for each separated system is executed (step), and the operation of the relay that responds to the system frequency is simulated (step).
Repeat (T / ΔT) times. If it is determined that there is a discontinuous change in the step, the step process is executed.

Next, when the above process is repeated, the power flow calculation at that point is executed (step), and the operation simulation of the overload relay or the voltage / reactive power control device that responds to the system voltage, power flow of the transmission line, etc. is executed. (Step), finally 1
A real-time synchronization process (delay) for synchronization of T seconds is executed (step), and the simulation for T seconds is completed. Then enter the simulation of the next cycle.

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

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

[Problems to be solved by the invention]

Since the conventional power system simulation is 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 breaker is turned on, the system may be broken again and the operation of the main protection / reserve protection relay cannot be simulated.

The present invention has been made in order to solve the above problems, and automatically processes the operation simulation of the main protection / reserve protection relay when a system failure occurs and automatically determines the disconnection state. At the same time, it is an object of the present invention to obtain a power system simulation system that can simulate the movement of the power system in the same way as the actual system even when a system failure occurs again due to an erroneous operation of the trainee.

[Means for solving problems]

The simulation system of the power system according to the present invention simulates the operation of the main protection / reserve protection relay based on the stability calculation, reflects the calculation result in the frequency / power flow calculation, and realizes the real-time simulation. It was realized.

[Action]

The simulation system of the power system in the present invention is
Based on the stability calculation, the operation simulation of the main protection / reserve protection relay is automatically processed, eliminating the need for manual setting in the training preparation stage of the trainee, and re-operation based on the erroneous operation by the trainer during the training. To be able to perform training in case of failure just like in the real system.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a CRT device, 2 is an accident sequence data file, and 3 is an SV-like data file. Even in the simulation system of the present invention, the step of transient stability calculation and the step of power flow / frequency calculation are executed. To do.

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.

Next, the operation of the above embodiment will be specifically described with reference to the flow charts of FIGS. 3 (a) and 3 (b).

First, in the training preparation stage, the trainer displays the time of failure occurrence, failure point in the power system on the screen of the CRT device 1,
The failure type is set using a light pen. The set data is stored in the accident sequence data file 2. Next, the operation judgment of the main protection / reserve protection relay, including the step-out relay, is performed by executing the transient stability calculation program with the accident sequence data file 2 as the input data, and the judgment result is judged. It is used as a main protection / reserve protection operation relay including a control relay and each state of the breaker (CB) is stored in the SV-like variable 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
The transient stability calculation including the operation simulation of the backup protection relay and the power flow / frequency calculation, which is the simulation of the power system, are executed in parallel (step, ). Also, as shown in FIG. 2, from the start of the training execution stage until T seconds, the operation judgment of the main protection / reserve protection relay is performed by the transient stability calculation (step) at the training preparation stage. Stability calculation is not executed, but power flow calculation and frequency calculation are executed (step).

In the simulation step thereafter, the transient stability calculation and the tidal current / frequency calculation are processed in parallel.

However, the transient stability calculation is not executed unless there is a failure in the cycle.

Further, the transient stability calculation is processed as shown in the flow charts of FIGS. 3 (a) and 3 (b), but the accident sequence file 2
The failure occurrence time, failure point, and failure type data are extracted from the data. If a failure occurs within T seconds after the time, the transient stability calculation is executed to simulate the operation of the main protection / reserve protection relay. The operation relay and the data of the breaker (CB) are added to the time and stored in the SV-like variable data file 3. In other words, the trainer does not simulate the operation of the main protection / reserve protection relay as in the conventional case, but simulates the operation by the transient stability calculation and stores it in the SV data file 3.

Next, the flow of processing will be described. First, it is determined whether or not a failure has occurred in the relevant cycle (step),
If no failure occurs, the calculation ends. On the other hand, if there is a failure, the result of power flow calculation 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 load bus voltage, active power and reactive power (step). .

Next, the admittance matrix of the positive-phase or 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. On the other hand, when there is a failure, the failure equivalent impedance added to the positive phase circuit is calculated based on the admittance matrix of the negative phase and zero phase circuits according to the type of failure (step).

Next, it is determined whether or not the fault has been removed (step), and if there is no fault, the process moves to changing the admittance matrix, and if there is, a process of treating the fault impedance as infinite is performed (step). Then, 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, the electric output of the generator is obtained using the voltage and current obtained in the step (step), and the internal phase angle of the generator is calculated by the equation of motion. Solve for (step).

Based on the above, the voltage and current of the network and the internal phase angle of the generator can be obtained.
Simulate the operation of a backup protection relay (step). Then, the presence or absence of the relay operation is determined by simulating the operation of the step (step), and if there is no relay operation, the process proceeds to the calculation end time determination process. On the other hand, if there is a relay operation, tripping or breaking (CB) occurs due to the relay operation.
To save the data in the SV-like variable data file 3 (step), and then determine whether the calculation time has reached T seconds (step). If it has not reached, the time is updated by Δt, and the processing from step is repeated.

On the other hand, the simulation of the power system executes the power flow calculation and the frequency calculation program while taking out the state change data of the SV-like variable data file 3 from the SV-like variable data file 3 in chronological order as shown in FIG. Real-time simulation of the electric power system is performed by simulating the operation of an overload relay, a frequency reduction relay, or a power / reactive power control device. The details of this real-time simulation will be described below with reference to the flowchart of FIG.

As an overall operation, frequency calculation and power flow calculation are combined every T seconds, and frequency calculation is performed in steps of ΔT seconds.
Calculate continuously (= T / ΔT) times.

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

The detailed operation is as follows: First, the SV-like data file 3 at that time.
If there is a change in the switch status, it is judged whether there is a change in the switch state (step). If there is a change, a system separation calculation is executed to determine whether there is a re-fault due to a malfunction of the trainee. The data is saved in the SV-like variable data file 3, and the isolated system is determined, the admittance matrix of the system is modified, and the system capacity and total inertial capacity of the separated system are calculated (step). Subsequently, after the completion of this system separation calculation, the power flow calculation is executed (step). On the other hand, if it is determined that there is no change in step, check whether there is a discontinuous change in the active power of the bus due to load or disconnection (step), and if there is no change, the same as the end of the power flow calculation. Then, the system frequency calculation for each separated system is executed (step), the operation of the relay that responds to the system frequency is simulated (step), and these processes are performed n times (T / Δ
T) Repeat. If it is determined that there is a discontinuous change in the step, the step process is executed.

When the above process is repeated n times in this way, 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, power flow of the transmission line, etc. is executed. (Step), and finally, real-time synchronization processing (delay) for synchronization of one cycle T seconds is executed (step), and the simulation for T seconds is completed. Then, enter the simulation of the next cycle. The system operation data from the trainer is input to the SV-like variable data file 3 as a program separate from the simulation. Further, T seconds are usually 3 to 5 seconds and ΔT is about 0.25 seconds.

In the power system simulation method according to the present invention, when the system scale is small, the real-time simulation can be realized even if the transient stability calculation and the power flow / frequency calculation are executed in series. Calculation and frequency calculation are shared by different computers, and for transient stability calculation, real-time simulation is realized by using a high-speed arithmetic processor such as an array processor.

〔The invention's effect〕

As described above, according to the present invention, the operation simulation of the main protection / reserve protection relay is realized based on the transient stability calculation. The effect of being able to simulate the movement of the system as well as the system of and improving the training effect.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of processing 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 processing flowchart of the transient stability calculation, FIG. 4 is a processing conceptual diagram of a 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, and 3 is an SV-like 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 with various data relating to a failure of a power system as input data,
The result of this execution is to save the SV condition data showing the status change of the main protection / repair relay and circuit breaker in the SV condition data file, and the main protection / repair relay and circuit breaker output by this SV condition data file. In the power system simulation method that simulates the operation of the power system by executing the power flow / frequency calculation program based on the SV change data, the operation simulation of the main protection / reserve protection relay is based on the transient stability calculation. The power system simulation method is characterized in that the power flow / frequency calculation program is executed based on the transient stability calculation result.