SU1480005A1 - Device for protecting synchronous generator against asynchronous operation - Google Patents

Abstract

The invention relates to the field of electrical engineering, namely, to relay protection and automation, and is intended to protect a synchronous generator from asynchronous operation. The purpose of the invention is to increase the selectivity and speed of the device in the asynchronous mode with the loss of excitation. For this purpose, an additional channel consisting of memory blocks and delays is introduced into the device, the elements BAN and AND, the combined action of which with the resistance measuring body, which has a special response characteristic, provides selective and fast action when the excitation is lost, accompanied by fast and intense oscillations. mi 2 Il.

Description

one

The invention relates to electrical engineering, in particular, to relay protection and automation, and is intended for use in protection devices for synchronous generators.

The purpose of the invention is to improve the reliability of the device by increasing the selectivity and speed in the asynchronous mode with the loss of excitation.

FIG. 1 shows a block diagram of the device; in fig. 2 shows the response characteristics of a measuring unit of resistance and hodographs of resistance in various modes.

At the output of the measuring unit 1, the first unit 2 of the operation delay and the execution unit 3 are connected in series.

The output of the measuring unit 1 also has a return delay unit 4, a second response delay unit 5, a BAN 6 element with two inputs, and an element 7. The resistance measuring unit 1 has a specific response area in the third and fourth quadrants of the complex resistance plane ( I and II in Fig. 2).

The device works as follows.

If the excitation is lost without significant oscillations, the resistance vector falls into region I and the device unloads the generator or shuts down with a delay of the first block 2 of the response delay. With this extra channel,

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The element consisting of elements 4–7 does not form an output signal, since the input signal arriving at the second (prohibiting) input of block 6 from the output of block 1 arrives earlier than the input signal coming to the first (enabling) input of block 6 from the output block 5, so that the output of block 6 has a blocking signal and element 7 does not work.

With synchronous oscillations (see curve 8 in Fig. 2), which have arisen, for example, due to the appearance of a disconnection, a short hodograph of the resistance can periodically fall into regions I and II (Fig. 2). However, the device does not work, since the time delay of the block 2 is chosen longer than the time of the hodograph of the resistance in the area of operation of the resistance block 1, and the additional subsequent closure (2 ".)

Thus, the additional channel from blocks 4–7 does not work when the first (point A) entry of a resistance hodograph in a given resistance region in the fourth quadrant of the complex resistance plane than

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The cable consisting of elements 4–7 also does not work, since with synchronous oscillations, the resistance oscillates slowly, and unit 4 during the absence of the response signal of the resistance measuring unit returns to its original state — JQ provides a detuning from the deep

which ensures the return of block 5. Therefore, with synchronous swings, block 6 retains a permanent blocking signal, and element 7 does not work.

When the excitation is lost, accompanied by significant and intense fluctuations of the resistance (see curve 9 in Fig. 2), the device does not have time to gain the required delay of the first block 2 of the response delay, but this ensures the operation of the device via the additional channel 4-7. When the resistance hodograph is first entered into the region of response of the organ of resistance at point A, block 4 remembers the trigger pulse for a specified time. Block 5 slows down the passage of this signal to the permissive input of block 6 and when the resistance block is triggered for the first time, block 6 prohibits channel operation. At the moment of time B, the hodograph of the resistance leaves the area of operation I, the resistance unit returns to its initial state, and at the moment of time C it is repeated to operate. Block 4 time delay

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synchronous swings. With synchronous oscillations, the resistance vector oscillations occur relatively slowly (see curve 8 in Fig. 2), and with possible repeated occurrences of the resistance hodograph in the region of operation, the device also does not work, since during the locus of the locus of the resistance outside region I or II block 4, the return delay has time to return to its original state. With fast and intense oscillations of the resistance hodograph in the fourth quadrant of the complex resistance plane, the device is rapidly acting to unload the generator, which increases the detuning of the device and its speed, as a result of which the set goal is achieved.

Claims (1)

Claims An apparatus for protecting a synchronous generator from an asynchronous stroke, comprising a resistance measuring unit, the current measuring inputs and voltage of which are intended for connecting respectively to current transformers and voltage the return delay is chosen longer than the pause time of the impulse response at the output of the resistance body from the moment B to C, equal to no more than 0.25 s, therefore the continuous working signal is present at the output of block 4. The time delay of block 5 is significantly less than the time delay of block 2, so by the time point B, an output signal appears at the output of block 5, which puts block 6 into a working state, since the signal at its second (prohibitory) input is disappears. Work signal output unit 6 is fed to the first input of element 7. At the time point C, the resistance body triggers again, the working signal appears at the second 0 input element And 7, the latter is triggered and through the execution unit 3 produces the unloading of the generator or its shutdown. Thus, the additional channel from blocks 4–7 does not work when the first (point A) entry of a resistance hodograph in a given resistance region in the fourth quadrant of the complex resistance plane than five Q provides detuning from deep five 0 five 0 five synchronous swings. With synchronous oscillations, the resistance vector oscillates relatively slowly (see curve 8 in Fig. 2), and with possible repeated occurrences of the resistance locus in the response region, the device also does not work, because during the locus of the locus the resistance is outside region I or II block 4 return delay time returns to its original state. With fast and intense oscillations of the resistance hodograph in the fourth quadrant of the complex resistance plane, the device is rapidly acting to unload the generator, which increases the detuning of the device and its speed, as a result of which the set goal is achieved. Claims An apparatus for protecting a synchronous generator from an asynchronous stroke, comprising a resistance measuring unit, the current measuring inputs and voltage of which are intended for connecting respectively to current transformers and voltage the stator of the generator, and the output of the measuring resistance unit through the first response delay unit is connected to the first input of the execution unit, which is different from the fact that, in order to increase the reliability of operation by increasing the selectivity and speed in asynchronous mode with loss of excitation, a delay return, the second block of the operation delay, the element BAN and the element AND, the input of the block for the return support is integrated with the blocking input of the element ZAPRGL and the first input of the element AND, and is connected to the output of the measuring resistance unit, the output of the support for return, through the successively connected second response delay unit, is connected to the 10 permitting input of the BANNER element whose output to the second input of the element I, and the output of the last to the second input of the said execution unit. ffa / x. I T VcT qjuv.i eight “F z 2