SU824366A1 - Method of preservation of power system stability - Google Patents

Description

The invention relates to electrical engineering, in particular, to methods and devices for maintaining the stability of power systems by affecting the excitation system and at the time of the driving motor of the synchronous generator. In the event of oscillation modes occurring along power lines and intersystem communications, the preservation of stability of the power systems can be achieved by acting on the automatic excitation controller (RRW) and at the time of the drive motor of the generator. Exposure of ARV generators and an increase in voltage in the power systems reduces the relative angles between the EMF vectors of the generators, which helps to eliminate the oscillations that have occurred. However, there are cases that are mainly associated with the circuit-mode features of the energy system, where it is not possible to eliminate the oscillatory regimes by increasing the voltage level. In this case, either a self-oscillation mode occurs, or a self-rebound, leading to a disturbance. stability. The effect to eliminate oscillatory instability on the unloading of the drive motor of the generator allows in all cases to achieve a positive result, however, under the conditions of reliable power generation, the use of fast unloading of turbines without extreme necessity is undesirable. The use of both of these methods together does not limit the amount of turbine unloading and can lead to unnecessary undesirable effects on the turbines. The closest in technical essence to the invention is the method according to which the deviation of the mode parameter is measured, compared with the setpoint and, if the measured deviation exceeds the setpoint, increase the set-up value of the APR l disadvantage with: the stability of the power systems and the device implementing this method is that the effect on changing the setpoint of an ARV generator in a number of cases may not be sufficiently effective and may not ensure the conversion of oscillatory modes into energy theme. It is also known a device for maintaining the stability of power systems, comprising a mode deviation sensor, an input and output comparison circuitry, a controllable key / extreme value detection unit, a memory unit, a time sensor and a voltage setting change unit ARV. At the same time, the output of the deviation sensor of the mode parameter is connected to the input of the first and second comparison circuits, and the setpoint signal is given to the input of the storage unit and through the contacting keys of the controllable key to the input of the unit to reveal an extreme value, and the output this comparison circuit. is connected to the control input of the key, the output of the block you are in-. of the extreme value is connected to the input of the time sensor, to the control input of the memory unit and to the blocking input of the output comparison circuit, the output of the time sensor is connected to the control input of the extreme value detection unit, the output of the memory block is connected to the second input of the output comparison circuit which is connected to the input of the unit for changing the setting of the automatic excitation controller (ARV) for the voltage Gz. The purpose of the invention is to increase the reliability of the power systems in the conditions of the occurrence of oscillatory modes. This goal is achieved by the fact that according to the method of maintaining the stability of power systems by measuring the deviation of the mode parameter, comparing it with the setpoint and, when the measured deviation exceeds the setpoint, increasing the setpoint of the ARV over time, after a predetermined setpoint of the APB, the deviation of the mode parameter, fix the extreme value of the deviation of the mode parameter from its average value exceeding the preset setpoint, and perform unloading of the prime mover l ronnogo generatoraJ if those chenie predetermined time f deviation amount exceeds modal pas Rs1metra fixed zna chenie. With the same purpose, a device for maintaining the stability of power systems containing a sensor for deviating a mode parameter, the output of which is connected to the inputs of the input and output comparison circuits, to the analog input of the storage unit and through the contacts of the controlled key to the input of the extreme value detection unit the comparator is connected to the control input of the control key, the output of the extremal value detection unit is connected to the blocking input of the output comparison circuit, to the input of the time sensor whose output It is connected to the control input of the extremal value detection unit, to the control input of the storage unit, the output of which is connected to the input of the output comparison circuit, the output of which is connected to the input of the voltage change setting block of the APB, is provided with an additional time sensor , the unit of formation. The signal to unload the primary engine of the generator, and the time sensor and input circuit cara-. They are controlled with blocking inputs, the input of the signal generator block for generator unloading through the closing contacts of the first additional control keys, as well as the input of the additional time sensor and the blocking inputs of the time sensor and the input comparison circuit are connected to the output of the second additional control key comparison, the output of an additional sensor time. It is not connected to the control inputs of the additional control keys. The figure shows the block diagram of the proposed device. The device contains a sensor 1 deviation of the resolved parameter, an input comparison circuit 2, an output circuit 3 of operation, an extremal value detection unit 4, a storage unit 5, time sensors 6 and 7, a voltage change setting unit 8 for ARV voltage, control signal 9-11 and a block 12 for forcing the signal to the generator load by active power. In the initial state, the comparison circuit 3 is locked, the comparison circuit 2 and the time sensors 6 and 7 are unlocked, the control keys 9 and 10 are open, the key 11 is closed. The device works as follows. From the output of sensor 1, the deviation signal of the mode parameter DP is fed to the input of the comparison circuit 2, to the second input of which a setpoint signal is applied. When the deviation signal of the mode parameter exceeds the setpoint at the output of the comparison circuit, a signal arrives at the control input of the key 9. The key 9 closes, 5 as a result of which the dp signal arrives at the input of the extreme value detection unit 4. When the signal P reaches an extreme value of P at the output of the block, a signal is generated, which is fed to the control input of the storage unit 5, to the input of the time sensor 6 and to the blocking input of the comparison circuit 3. Under the influence of this signal. La starts the time sensor 6 and. . the lock is removed from the comparison circuit 3. In addition, under the action of this signal, in block 5, the current value of the deviation of the 1-mode parameter, which at this moment of time is fed to the analog input of the storage unit 5, is memorized. The value of the DP, recorded in block 5, corresponds to the extreme value of the deviation of the mode parameter l P.

The analog inputs of the comparison circuit 3 receive a signal from the output of block 1, which is proportional to the deviation of the operational parameter of the PD, and from the output of block 5, a signal proportional to the extreme value, the deviation of this parameter l P. After the lock is removed in the comparison circuit 3, a comparison is made d PD with the current h value of DP.

When the signal dp is exceeded, the value of LPS at the output of comparison unit 3 a signal appears, which is fed to the input of block 8, which changes the setpoint of the generator's automatic voltage generator and triggers it, causing the setpoint of the automatic switching device to increase.

The output signal of the comparison circuit 3 through the disconnecting contacts of the control key 11 is also fed to the input of the time sensor 7, its start, and to the blocking inputs of the time sensor 6 and the input comparison circuit 2. The signal, popping on the blocking input of the sensor 6 time, causes the stop and the subsequent reset of the time sensor. Stopping the time sensor leads to the appearance of a signal at its output, which, arriving at the control input of the unit 4 for detecting an extreme value, causes the signal to be removed at its output. The disappearance of the signal at the output of block 4 leads to the deletion of the value of the DP in the block 5 of memory, the signal at the output of block 5 becomes equal to zero. Simultaneously with the disappearance at the output of block 4, the comparison circuit 3 is blocked.

After the time C, specified by the time sensor 7 and selected based on the decay condition of the transient process caused by a change in the voltage-controlled setting of the APB, the signal from the output of sensor 7 entering the control inputs of keys 10 and 11 removes the lock from the comparison circuits The contacts of the key 10 commute the input of the signal generation unit 12 to the generator unloading, with the output of the unit 3.

After the completion of the above operations, all the blocks of the device, with the exception of the keys 10 and 11 and block 8, are in the initial state and the device is again ready for detection of oscillatory processes.

If the voltage fluctuations in the power system continue after the increase in the ARV voltage setting, the device re-detects (block 4) and stores (block 5) the new extreme value of the deviation of the mode parameter. At the same time, the time sensor B is started and the output comparison circuit 3 is unlocked. After removing the block in comparison circuit 3, a comparison is made of the current value of the deviation of the mode parameter d P with a recorded extremum d 3.

If during the time period Td specified by the sensor 6, the condition AP D Pe is satisfied (fluctuations in the power system are damped), the topo after a specified period of time stops and then resets the sensor 6 to time. When the time sensor is stopped, the blocks 3, 4 and 5 return to the initial state. If the power system occurs

0 if it is self-extracting (dp becomes greater than A dd), then at the output of the comparison circuit 3 a signal appears that through. The closed contacts of the key 10 are supplied to the input of the block 12 by a signal to unload. When applying a signal to the input of unit 12, a signal is formed at its output, in accordance with which the turbine is unloaded.

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The present invention makes it possible to promptly detect the occurrence of continuous oscillations in the power system and stop them due to the effect on the excitation system and in some cases at the time of the drive engine of the generator. This minimizes the number of impacts and emergency turbine unloading.

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Claims (1)

1. A method for maintaining stability 5 of the power systems by measuring the deviation of the mode parameter, comparing it with the setpoint and, when the measured deviation of the setpoint is exceeded, increase the setpoint of the two-rule ARV generator excitation controller 0 by voltage, from the power supply and from the fact that, in order to increase the reliability of operation of the power system in the conditions of oscillation regimes, after a given interval 5 times t after increasing the setpoint of APB, the deviation of the mode parameter is re-measured, and the extreme value of the deviation is fixed. parameter from its average value, 0 is greater than the specified setpoint, and the primary engine of the generator is unloaded if, for a given time C, the deviation of the mode parameter exceeds the fixed value.