RU2337453C1 - Method of control of disconnection and successful automatic reclosure of sectionalising circuit breaker in ring line - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: method consists in the fact that from the moment of appearance of the first short-circuit current inrush (sc) in busbars of transformer that supplies the line, time count is started equal to time of sectionalising circuit breaker protection actuation, at that moment of disconnection of the first short-circuit current inrush is controlled, and if the moment of time count completion coincides with the moment of disconnection of the first short-circuit current inrush, then fact of sectionalising circuit breaker disconnection is established, at that from the moment of disconnection of the first short-circuit current inrush time delay of automatic reclosure is started, at that appearance of the second current inrush is controlled, and if in the moment of automatic reclosure time delay count completion there appears current inrush with value of more than normal operating value, but less than short-circuit current, then after that fact of disconnection and successful automatic reclosure of sectionalizing circuit breaker installed in ring line.

EFFECT: expansion of functional resources of sectionalising circuit breakers.

2 dwg

Description

The invention relates to the automation of electrical networks and is intended to control the tripping and successful automatic restart (reclosure) 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.

A known method of controlling the tripping and unsuccessful automatic restart of the sectionalizing circuit breaker in the line of the ring network, which consists in the fact that since 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 the second short-circuit current surge, and if after its appearance, at the end of the counting of the total time, the second short-circuit current break ., then establish the fact of unsuccessful reclosure of a sectioning switch installed in the line of the ring network [Patent No. 2304338, Cl. H02J 13/00, 2006].

The disadvantage of this method is the impossibility of using it to control the successful automatic reclosure of a sectionalizing circuit breaker in a ring network powered by two-transformer substation buses, after the fact of switching off a sectioning circuit breaker has been established.

The objective of the invention is to expand the functionality of the method by obtaining information about the successful reclosure of a sectionalizing circuit breaker in a ring network line powered by two-transformer substation buses, after establishing the fact of switching off a sectioning circuit breaker.

According to the proposed method, a fixed inrush current short circuit on the tires of the transformer supplying the ring network line. From the moment of 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 establish the fact of switching off the sectioning switch. And then from the moment of switching off the first inrush short-circuit start the countdown of the reclosure time, while controlling the appearance of the second inrush current, and if at the end of the countdown of the reclosure time the current surge appears with a value greater than the normal operating current, but less than the short-circuit current, then the fact of tripping and successful reclosure of the sectioning switch is established installed in a ring network line.

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, when short 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, item NOT 7, one-shot 8, item AND 9, the element MEMORY 10, the element DELAY 11, the one-shot 12, the element 13, the recording device (RU) 14, the power transformer 15, the power transformer 16, the sectional substation switch 17, the head switch of the first line of the ring network 18, the head switch of the second line ring network 19, sectional off switch of the first line of the ring network 20, switch of the point of automatic inclusion of the reserve 21, point short-circuit 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, the monitored section switch 1 is turned on. At the output of the TT 2 there is a certain value of the output signal (Fig. 2, diagram 23), due to the operating current, but insufficient for the operation of the DTKZ 3 and the single-shot 8, so the presence of the output signal from the element HE 7 at the first input of the circuit element And 9 is not enough for it triggering (see figure 1). The circuit does not start.

When short at point 22 (see Fig. 1), the value of the output signal of current transformer 2 (Fig. 2, diagram 23) will be sufficient for tripping of DTKZ 3, therefore a signal appears at its output (Fig. 2, diagram 24), which will be input element MEMORY 4 and element NOT 7 (see figure 1). From the output of the element NOT 7, the signal disappears (Fig. 2, diagram 28), which arrived at the first input of the And element 9. The signal from DTKZ 3 is stored by the MEMORY element 4 (Fig. 2, diagram 25) and goes to the input of the element DELAY 5 whose signal will appear after a time equal to the response time of the protection of the sectioning switch (figure 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 impulse (figure 2, diagram 27), which will "reset" the element MEMORY 4 and go to the second input of element And 9. If at the same time under the influence of the maximum current protection controlled sectioning switch 1 (see figure 1) will turn off the short-circuit current, then with DTKZ 3 the output signal will disappear (see figure 2, diagram 24). There will be an output signal from the element NOT 7 (see figure 2, diagram 29), which will go to the first input of the element And 9. The simultaneous presence of two input signals at the input of the element And 9 leads to the appearance of its output signal (figure 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 remembered 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 will appear after a time equal to the exposure time of the automatic reclosure sectioning switch (Fig. 2, diagram 32). The signal from element 11 will go to the input of a 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 first input of the element And 13 (see figure 1). After the exposure time of the reclosure, the switch 1 (see figure 1) will turn on. Moreover, if the inclusion is successful (short-circuit unstable), then at the output of the current transformer 2 a signal appears (figure 2, diagram 23), insufficient for tripping of DTKZ 3 (figure 2, diagram 24), but sufficient for operation of the element single vibrator 8 (figure 2, diagram 29). The output signal from the single-shot 8 will go to the second input of the element 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, chart 34), which will be received in RU 14 (see figure 1) and ensure that there is information that a successful reclosure of a sectioning switch installed in the ring network line has occurred.

Thus, the method allows to obtain timely information about the tripping and successful automatic reclosure of the sectionalizing circuit breaker in the ring network line powered by the buses of a two-transformer substation.

Claims (1)

A method for controlling the tripping and successful automatic restart (AR) of a sectionalizing circuit breaker in a ring network line powered by two-transformer substation buses, which consists in the fact that from the moment of the first inrush of short circuit current (short circuit) on the busbars of the transformer supplying the line, start the countdown of time equal to the response time of the protection of the sectionalizing circuit breaker, while controlling the moment of disconnection of the first inrush short-circuit current, and if the end time of the countdown coincides with the moment off cheniya first throw short-circuit current, the set fact partitioned off switch, characterized in that further since the tripping fault current the first roll start the countdown of the reclosure time, while controlling the appearance of the second inrush current and if at the end of the countdown of the reclosure time the current surge appears with a value greater than the normal operating current, but less than the short-circuit current, then the fact of tripping and successful reclosure of the sectioning switch is established, installed in a ring network line.

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