RU2304338C1 - Method for checking sectionalizing circuit breaker for disconnection and automatic reclosure failure in ring-network line - Google Patents

Abstract

FIELD: automatic control of electrical networks.

SUBSTANCE: proposed method depending on reception of information about disconnection or automatic reclosure failure of sectionalizing circuit breaker in ring-network line supplied with power from buses of double-transformer substation includes readout of time interval starting from first short-circuit inrush current in buses of line feeding transformer equal to operating time of sectionalizing circuit breaker protective gear; in the process disconnection of first short-circuit inrush current is checked and if end-of-time-reading moment coincides with moment of disconnection of first short-circuit inrush current, fact of sectionalizing circuit breaker disconnection is established and then total time equal to automatic reclosure period of this circuit breaker and operating time of accelerated protective gear of the latter is read out from the moment of disconnection of first short-circuit inrush current; in the process occurrence of second short-circuit inrush current is checked and in case of disconnection of this second inrush current at the moment of total time reading completion, fact of automatic reclosure failure of sectionalizing circuit breaker installed in ring-network line is established.

EFFECT: enlarged functional capabilities.

1 cl, 2 dwg

Description

The invention relates to the automation of electrical networks and is intended to control the tripping and unsuccessful automatic restart (AR) of the sectionalizing circuit breaker in the line of the ring network, powered by buses of a two-transformer substation. Moreover, a sectional switch equipped with a single-acting reclosure device is installed in the line.

There is a method of obtaining information about the result of the automatic restarting of the sectioning apparatus, which consists in fixing the inrush current of the short circuit (short circuit), measuring the time after it disappears before the appearance of the second inrush current and monitoring the on position of the switch at the beginning of the line after the disappearance of the first inrush current .z. with subsequent measurement of the magnitude of the second inrush, and if it is greater than the normal operating current, but less than the short-circuit current, a successful automatic restart is detected, and if it is equal to or greater than the short-circuit current - unsuccessful [Auth. St. No. 851644. Cl. H02J 13/00, 1981].

The disadvantage of this method is the impossibility of using it to control the shutdown and the unsuccessful automatic reclosure of the sectionalizing line circuit breaker in the ring network powered by the buses of a two-transformer substation.

The objective of the invention is to expand the functionality of the method by obtaining information about the tripping and unsuccessful reclosure of a sectionalizing circuit breaker in a ring network line powered by buses of a two-transformer substation.

According to the proposed method, the occurrence of inrush currents is detected. on the tires of a transformer called short-circuit in line powered by this transformer. When the first inrush short circuit occurs start the countdown of time equal to the response time of the protection of the sectioning switch, while controlling the moment of disconnection of the first inrush current If the end time of the operation time of the protection of the sectionalizing circuit breaker coincides with the moment of switching off the first inrush short-circuit current, then the fact of tripping the sectioning circuit breaker is established. And then, from the moment of switching off the first short-circuit current surge, the countdown of the total time equal to the reclosure time of this switch and the response time of its protection with acceleration is started, while the appearance of the second short-circuit current surge is controlled. And if, after its appearance, at the end of the countdown of the total time, the second short-circuit current surge is disconnected, then after that the fact of the unsuccessful reclosure of the sectioning switch installed in the ring network line is established.

The essence of the invention is illustrated by drawings, where

figure 1 presents a structural diagram containing elements for implementing the method;

figure 2 - diagrams of the signals at the outputs of the elements shown in figure 1 with short circuit at point 22 (see figure 1).

The circuit (see Fig. 1) contains: a controlled sectional switch 1, current transformer (CT) 2, short-circuit current sensor (DTKZ) 3, element MEMORY 4, element DELAY 5, one-shot 6, element OR 7, element NOT 8, element And 9, element MEMORY 10, element DELAY 11, one-shot 12, element And 13, recording device (RU) 14, power transformer 15, power transformer 16, sectional substation switch 17, head switch of the first line of the ring network 18, head switch of the second ring network lines 19, sectional off ring network ents the first line 20, the switch point automatic transfer switch 21, a short-circuit point 22.

The signal diagrams at the outputs of the elements shown in figure 1 with a short circuit at point 22 (see figure 1) have the form (see figure 2): 23 - at the output of element 2; 24 - at the output of element 3; 25 - at the output of element 4; 26 - at the output of element 5; 27 - at the output of element 6; 28 - at the output of element 7; 29 - at the output of element 8; 30 - at the output of element 9; 31 - at the output of element 10; 32 - at the output of element 11; 33 - at the output of element 12; 34 - at the output of element 13; 35 - the availability of information in element 14.

The method is as follows. In normal operation, section switch 1 is turned on. At the output of TT 2 there is a certain value of the output signal (figure 2, diagram 23), due to the operating current, but insufficient for tripping of DTKZ 3, therefore, the presence of the output signal from the element HE 8 at one of the inputs of the circuit elements And 9 and And 13 is not enough their triggering. The circuit does not start.

When short at point 22 (see Fig. 1), the output signal of TT 2 (Fig. 2, diagram 23) will be sufficient for triggering DTKZ 3, therefore, a signal appears in its output (Fig. 2, diagram 24), which will be received at the input of MEMORY 4 and the element is NOT 8 (see figure 1). From the output of the element NOT 8, the signal will disappear (Fig. 2, diagram 29). The signal from DTKZ 3 is stored by the element MEMORY 4 (Fig. 2, diagram 25) and is fed to the input of the element DELAY 5, from the output of which the signal will appear after a time equal to the response time of the protection of the sectioning switch (Fig. 2, diagram 26). From the output of element 5, the signal will go to the input of one-shot 6, this element will give a single pulse (figure 2 diagram 27), which will be fed to the input of element OR 7 and the input of element And 9. A signal will appear at the output of element OR 7 (figure 2 diagram 28 ), which will “reset” the MEMORY element 4. If at the same moment under the influence of the overcurrent protection the controlled sectionalizing switch 1 (see Fig. 1) disconnects the short-circuit current, then the output signal will disappear from DTKZ 3 (see Fig. 2 chart 24). When this occurs, the output signal from the element NOT 8 (Fig. 2, diagram 29), which will be supplied to the inputs of the elements And 9 and I 13. The presence of two input signals at the input of the And 9 element leads to the appearance of its output signal (Fig. 2, diagram 30) , which will go to the input of the element MEMORY 10 and in RU 14 (see Fig. 1). At the same time, information will appear in RU 14 that a sectioning switch is disconnected in the ring network line. The signal from the element And 9 is stored by the element MEMORY 10 (Fig. 2, diagram 31) and is fed to the input of the element DELAY 11, from the output of which the signal appears after the total time equal to the reclosure time of the sectioning switch and the response time of its protection with acceleration (Fig. 2 diagram 32). The signal from element 11 will go to the input of the single-shot 12, this element will give a single pulse (figure 2 diagram 33), which will "reset" the element MEMORY 10 and will go to the input of the element And 13 and the element OR 7 (see figure 1). After the time delay of the automatic reclosure of the sectioning switch, its circuit breaker 1 (see Fig. 1) will turn on and there may be a case of its inclusion on a stable short circuit Since the value of the output signal of TT 2 (FIG. 2, diagram 23) is sufficient for triggering of DTKZ 3, the signal again appears at its output (FIG. 2 diagram 24), which will be received at the input of MEMORY 4 and NOT 8 (see figure 1). From the output of the element NOT 8, the signal will disappear (Fig. 2, diagram 29), received at one of the inputs of the elements And 9 and And 13. After the automatic reclosure of the controlled sectioning switch 1 to a stable short circuit it will turn off with acceleration and it will turn off the second inrush short-circuit current (figure 2 diagram 23). In this case, with the DTKZ 3, the output signal will disappear (see Fig. 2, diagram 24). There will be an output signal from the element NOT 8 (see figure 2, diagram 29), which will go to the inputs of the elements And 9 and And 13. The presence of two input signals at the input of the element And 13 will lead to the appearance of its output signal (figure 2 diagram 34) , which will go to RU 14 (see FIG. 1) and ensure that there is information that there was an unsuccessful reclosure of a sectioning switch installed in the ring network line.

Because at the second inrush short-circuit the signal from DTKZ 3 will again be remembered by the element MEMORY 4, and then the DELAY 5 element may trigger, the signal from the output of which will go to the input of the one-shot 6, and from it to the input of the And 9 element (see Fig. 1). In this case, the signal will appear after a time equal to the response time of the protection of the controlled sectionalizing switch 1 (Fig. 2, diagram 26), and if the automatic reclosure is unsuccessful, the controlled sectionalizing switch 1 (see Fig. 1) will turn off with acceleration, and the signal from the element NOT 8 will appear on input element And 9 in time earlier than when you turn off the first inrush short circuit Therefore, to prevent repeated operation of the And 9 element, when the second short-circuit current is disconnected, the signal from the one-shot 12 (see Fig. 2, diagram 33) will be input to the OR element 7 and will lead to the appearance of a signal at its output (see Fig. .2 diagram 28). In this case, the signal from the output of the element OR 7 "reset" the element MEMORY 4 (see figure 1). Therefore, at the input of the element And 9, after turning off the second inrush current short circuit, there will be only one input signal coming from the element NOT 8, and therefore there will be no signal at its output (figure 2 diagram 30). Therefore, in RU 14 there will be information that at first the controlled sectionalizing circuit breaker tripped, and then its unsuccessful reclosure.

Thus, the method allows to obtain timely information about tripping and unsuccessful automatic restarting of the sectioning switch in the line of the ring network, powered by the buses of the two-transformer substation. This will lead to an increase in the reliability of power supply to consumers through the adoption of necessary decisions based on the information received by operational personnel.

Claims (1)

A method for controlling the tripping and unsuccessful automatic restart (AR) of a sectionalizing circuit breaker in a ring network line powered by two-transformer substation buses, which consists in fixing the inrush currents of a short circuit (short circuit) and measuring the time between them, characterized in that from the moment the appearance of the first inrush short-circuit on the tires of the transformer supplying the line, a countdown starts, equal to the response time of the protection of the sectionalizing circuit breaker, and the moment of switching off the first inrush short-circuit current is monitored, and if the end time of the countdown coincides with the moment of disconnection of the first inrush short-circuit current, then first establish the fact of disconnecting the sectioning switch, and then from the moment of disconnection of the first inrush short-circuit start the countdown of the total time equal to the reclosure time of this switch and the response time of its protection with acceleration, while controlling the appearance of a second inrush current short circuit and, if after its occurrence, at the end of the countdown of the total time, the second short-circuit current surge trips, then after that the fact of the unsuccessful reclosure of the sectioning switch installed in the ring network line is established.

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