JPH01259797A - Simulation circuit of generator for analog simulator - Google Patents

Abstract

PURPOSE:To prevent a model from its unstable action due to a circuit delay by giving an instruction value to a sinusoidal wave generating circuit considering its delay and an amplifier in its delay. CONSTITUTION:First, terminal voltage of a generator and its current are read through an input device 3. Next being based on this read value, the generator calculates its internal voltage and current by a Park's equation or the like. While the equation of motion is solved. By these calculation, voltage amplitude, phase and a frequency of the generator in the next step are calculated and output to a sinusoidal wave generating circuit 4 through an output device 2. Here a preset circuit adds its delay to be output. By the method thus obtained, a simulation circuit eliminates its delay, even when a large disturbance is analyzed, unstable action is prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a generator simulation circuit for an analog simulator used for power system analysis, etc., and particularly to a high-performance generator simulation circuit that compensates for time delays and phase delays in the simulation circuit. Concerning generator simulation circuits.

[Conventional technology]

Analog simulators, which are miniature models of real power systems, have been used to develop power system control and protection devices and perform system analysis. However, when using equipment that is smaller than the actual system, there are problems such as large losses and the inability to faithfully simulate the constants of one equipment. Therefore, in order to match the losses of the actual system and the simulator, a simulation circuit with loss compensation is used as a simulation circuit for the equipment used, and in order to faithfully simulate the operation of the generator, various characteristics of the generator are calculated using a computer. A method is being considered that simulates a generator by calculating and converting the result into an analog three-phase sine wave.

[Problem to be solved by the invention]

According to such a method of simulating a generator, various constants and characteristics of the generator can be adjusted arbitrarily using computer software, so that a generator model that is almost equivalent to the actual system can be obtained. However, calculations using a computer calculate various characteristics based on sampled values, and it is necessary to convert the digital output calculated by the computer into a three-phase sine wave analog output and amplify it to the required level. A time delay and a phase delay occur between input and output. For this reason, when a large disturbance occurs in the grid, the generator model may operate unstablely during analysis.

An object of the present invention is to provide a high-performance generator simulation circuit that can always operate stably, while eliminating the drawbacks of the generator simulation circuit described above.

[Means to solve the problem]

The above object is achieved by giving a command value to a sine wave generation circuit that generates an analog three-phase sine wave, taking into account the input/output delay of the computer, the delay of the sine wave generation circuit, and the delay of the amplifier.

[Effect]

The generator simulation circuit includes a computer to calculate the characteristics, its input/output device, a sine wave generation circuit to generate a three-phase sine wave based on the calculation results, an amplifier and a generator to amplify the power of the sine wave. It consists of a detection circuit that detects the terminal voltage and current of each circuit, and the phase delay of each circuit with respect to time and commercial frequency (frequency of the system to be analyzed) can be known in advance. Therefore, if the phase angle command value of the sine wave generating circuit is given in consideration of this delay, the delay of the simulating circuit will be eliminated, and unstable operation will not occur even when analyzing a large disturbance.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. Figure 1 shows a simulated generator circuit.

1 is a calculator for calculating the internal voltage of the generator, 2 is an output device for taking out the calculation results, 3 is the generator current,
An input device for inputting the terminal voltage into the computer 1, 4 is a three-phase sine wave generating circuit that outputs a three-phase sine wave from the angular frequency ω, phase θ, and voltage amplitude ■ output from the computer; The waveform of the phase component is expressed by the following equation.

E=Vm sin ((11 to 10) −
(1) 51 to 53 are amplifiers that amplify the power of three-phase sine waves, 6 is a current detection circuit that detects the output current of the generator, 7 is a voltage detection circuit that detects terminal voltage, and 8 is connected to the generator Represents the load system. 9 represents an initial value setting device, the details of which are shown in FIG. In FIG. 2, reference numeral 91 represents an initial value setting circuit, which is set with the initial values (for example, frequency, phase, voltage amplitude, etc.) of the generator in the system that are calculated off-line by a computer using a power flow calculation program or the like. 92 is calculated by totaling the delay of the output device from the output command of the computer until the command value of frequency 1 phase and voltage amplitude reaches the three-phase sine wave generation circuit, the input/output delay of the sine wave generation circuit, and the delay of the amplifier. A circuit for setting a correction value for correcting the result output value; 93 is an input circuit for inputting the set value of 91.92 into the computer 1; FIG. 3 shows the flow of specific processing contents within the computer. Inside the computer, there is a program for calculating the characteristics of the generator, and in order to perform numerical calculations using this program, first, the terminal voltage and current of the generator are read through the input device 3. Next, based on this value, the internal voltage of the generator is calculated using Park's equation, etc.
Calculate the current. Also, solve the equation of motion. Based on these, the voltage amplitude, one phase, and frequency of the generator in the next step are calculated, and the output device 2 outputs these to the sine wave generating circuit 4 via the output device 2. At this time, a preset circuit delay is added and output. After that, time is advanced for the first step calculation, and the process of reading the terminal voltage and current again for the command value calculation in the next step is repeated. In this case, in order to synchronize the timing between the external analog signal (generator voltage) and the computer, a method is used in which the calculation process shown in FIG. 3 is synchronized with an external clock.

FIG. 4 shows an example of a power system with a 3 Ja generator. 801 to 803 are generators made of the generator model explained above, and assuming that 801 is the generator part in Figure 1, the load system in Figure 1 is the right side including the transformer 811 in Figure 4. represent (Similarly.) 811 to 813 are transformers,
822 to 82; 3 is a load, 831 and 832 are AC/DC converters for DC power transmission, 841 is a DC transmission line, and 842 and 843 are AC transmission lines.

When analyzing such a system, the voltage amplitude, phase, and frequency of the sine wave of each generator are calculated in advance according to the power flow conditions. Based on this result, each generator sets initial values, operates the generator at the start of operation (generator start command), and performs a current system analysis in the event that a ground fault occurs, for example at point F in the diagram. be able to.

According to the present invention, since an output can be obtained that takes into account the delay of the generator simulation circuit, unstable operation of the generator simulation circuit due to the delay of the simulation circuit can be prevented, and a high-performance generator model can be obtained.

FIG. 5 shows another embodiment of the invention. In the above, the circuit delay is considered in the frequency, phase angle, and voltage amplitude that are the calculation result outputs, but in this figure, the circuit delay is taken into account as the calculation step time. In other words, the current time. , the time of the next step is jn+1. If the delay time of 1-1 tar of the circuit is Δ, then t n"1"l'. +ΔL
...It is expressed as (2). The flow for this purpose is shown in FIG.

The difference from the flow shown in FIG. 2 is that the calculation results are output as they are without being corrected, and the 1-time step is corrected by Δt as shown in equation (2).

It is clear that this method also corrects the delay in the simulation circuit, and as described above, it is possible to prevent unstable operation of the generator simulation circuit due to delay in the simulation circuit.

The initial value setting circuit shown in Figure 2 is configured to be directly connected to a computer containing an initial value calculation program for the power system to be analyzed, which saves the trouble of setting initial values, making it an easier-to-use generator model. can be obtained.

In addition, to start the generator, use the initial value calculated in advance as the start command (obtained from the simulator's control panel).
This can be done by outputting to a three-phase sine wave generating circuit.

〔Effect of the invention〕

According to the present invention, a three-phase sine wave output that takes into account the delay of the generator simulating circuit can be easily obtained by changing the software, which has the effect of preventing unstable operation of the model due to one circuit delay.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a generator simulation circuit according to an embodiment of the present invention, Fig. 2 is a detailed block diagram of the initial value setting device in Fig. 1, and Fig. 3 is a processing of the computer shown in Fig. 1. Flow diagram, 4th
The figure is a power system diagram consisting of a three-machine system, and FIG. 5 is another processing flow diagram of the computer of the generator simulation circuit of the present invention. DESCRIPTION OF SYMBOLS 1... Computer, 2... Output device, 3... Input device, 4... Three-phase sine wave generation circuit, 6... Current detection circuit, 7... Voltage detection circuit, 8...・Load system, 9...
Initial value setting device, 51-53...Amplifier, 91...
Initial value setting circuit, Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] 1. A computer that calculates the characteristics of a generator, a sine wave generation circuit that outputs a sine wave voltage with an amplitude, phase, and frequency according to the calculation results, an amplifier that amplifies the voltage, and a power generator. In a generator simulation circuit for an analog simulator, which consists of a device for importing the terminal voltage and output current of the generator simulation circuit into a computer, calculations of voltage amplitude, phase, and frequency are performed to take into account delays inside the simulation circuit. A generator simulation circuit for an analog simulator, characterized in that a value obtained by adding a correction value to the result is used as a command value for the sine wave generating circuit. 2. In the analog simulator generator simulation circuit according to claim 1, the time step is corrected by the delay time in order to take into account the internal delay of the simulation circuit. Simulated circuit.