RU2397595C1 - Control method of unsuccessful automatic repeated fault close-in, and further failure of shutoff of sectionalising circuit breaker in power transmission line - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: short circuit current surge is fixed, time is measured after it disappears prior to the second current surge and the switched on position of circuit breaker is controlled at the beginning of the line after the first short circuit current surge disappears, with further measurement of the second current surge value, and if it is higher than normal operating current but less than short circuit current, successful automatic reclosure is fixed, and it is equal or more than short circuit current, unsuccessful automatic reclosure is fixed. At that, there fixed is the moment when the first short circuit current surge appears at the beginning of power transmission line; that moment is saved, and count of total time equal to actuation time of protection and exposure time of automatic relcosure of sectionalising circuit breaker is begun; and when it is elapsed, the second short circuit current surge is expected, and when the fixing moment of the second short circuit current surge coincides with the terminal moment of the above count, there begun is count of actuation time of protection with acceleration of sectionalising circuit breaker, and if at the moment when it is finished, the second short circuit current surge is not switched off, then automatic reclosure and further failure of shut-off of sectionalising circuit breaker in power transmission line is considered unsuccessful.

EFFECT: enlarging functional capabilities of the method.

2 dwg

Description

The invention relates to the automation of electrical networks and is intended to control the unsuccessful automatic restart (AR) for a short circuit (short circuit) and the subsequent failure to disconnect the sectioning switch in the power line. Moreover, a sectional switch equipped with a single-acting reclosure device is installed in the line.

A known method of obtaining information about the result of the automatic restart of the sectioning apparatus, which consists in fixing the inrush current of the 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 of the short circuit, with the 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 current k. . - unsuccessful [Auth. St. No. 851644, Cl. H02J 13/00, 1981].

The disadvantage of this method is the impossibility of using it to control the unsuccessful reclosure on the short circuit and subsequent failure to disconnect the sectioning switch in the power line.

The task of the invention is to expand the functionality of the method by obtaining information about the unsuccessful reclosure on short circuit. and subsequent failure of disconnecting the sectioning switch in the power line.

According to the proposed method, the instant of occurrence of the first inrush short-circuit current is recorded. at the beginning of the power line. They memorize it and start counting the total time equal to the response time of the protection and the exposure time of the automatic reclosure sectioning switch. After the countdown of the total time, the appearance of a second inrush short-circuit current is expected With the coincidence of the moment of fixation of the second inrush short circuit and at the end of the countdown of the aforementioned time, the countdown time of the protection starts with the acceleration of the sectioning switch. And if at the end of the countdown of the response time of the protection with acceleration, the second short-circuit current fault does not turn off, then the fact of the unsuccessful reclosure on the short circuit is established. and subsequent failure to disconnect the sectioning switch in the power 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 with short circuit at point 17 (see figure 1).

The circuit (see Fig. 1) contains: a controlled sectional switch 1, a power transformer 2, an input bus switch 3, power lines W1, W2, W3, W4-4, a head power line switch W1 5, a current transformer (CT) 6, short circuit current sensor (DTKZ) 7, element MEMORY 8, element DELAY 9, element NOT 10, element BAN 11, element I 12, element DELAY 13, element REPEATER 14, element I 15, recording device (RU) 16, point to .z. 17, S1 and S2 are loads.

Diagrams of the signals at the outputs of the elements shown in figure 1 at short circuit at point 17 (see figure 1), have the form (see figure 2): 18 - at the output of element 6; 19 - at the output of element 7; 20 - at the output of element 8; 21 - at the output of element 9; 22 - at the output of element 10; 23 - at the output of element 11; 24 - at the output of element 12; 25 - at the output of element 13; 26 - at the output of element 14; 27 - at the output of element 15; 28 - the availability of information in element 16.

The method is as follows. In normal operation, section switch 1 is turned on. At the output of TT 6 there is a certain value of the output signal (figure 2, diagram 18), due to the operating current, but insufficient for tripping of DTKZ 7. There is an output signal from the element HE 10 at the prohibit input of the element BAN 11. The circuit does not start.

When short at point 17 (see Fig. 1), the value of the output signal of the TT 6 (Fig. 2, diagram 18) will be sufficient for the DTKZ 7 to operate, therefore, a signal appears at its output (Fig. 2, diagram 19), which will be fed to the inputs of the elements MEMORY 8, PROHIBITION 11 and AND 15 (see figure 1). The signal from DTKZ 7 is stored by the element MEMORY 8 (figure 2, diagram 20) and is fed to the input of the element DELAY 9, from the output of which the signal appears after the total time equal to the response time of the protection of the sectioning switch and the holding time of the automatic reclosure of the sectioning switch (figure 2, chart 21). From the output of the element BAN 11, the signal does not appear, because There is an output signal from the element NOT 10 at its inhibitory input. The presence of one signal at the input of element And 15 will not lead to its operation.

After counting the total time (see above) at the output of the DELAY element 9, a signal will appear (figure 2, diagram 21) and will be input to the elements AND 12 and NOT 10. The signal at the inhibitory input of the element BAN 11 will disappear (figure 2, diagram 23 ) If at this point in time after an uninterrupted pause of the automatic reclosure, the sectioning switch 1 is turned on and it can be turned on for a stable short circuit, then the output signal of the TT 6 (Fig. 2, diagram 18) will be sufficient to operate the DTKZ 7, therefore the output again appears a signal (figure 2, diagram 19), which will go to the inputs of the elements MEMORY 8, BAN 11 and AND 15 (see figure 1). At the same time, from the output of the element BAN 11, the signal will appear (figure 2, diagram 23), and the presence of one signal at the input of the element AND 15 will not lead to its operation. From the output of the element 11, the signal will go to the second input of the element And 12, it will work (figure 2, diagram 24). The signal at the output And 12 will go to the input of the DELAY 13 element and to RU 16. Information on the unsuccessful reclosure of the sectioning switch 1 will appear in RU 16 (Fig. 2, diagram 28). From the output of the DELAY 13 element, the signal will appear after the countdown of the protection operation with the acceleration of the sectioning switch 1 (Fig. 2, diagram 25) and will go to the input of the REPEATER 14. The element REPEATER 14 will give a signal with a specified duration, which will be input to the element And 15 and MEMORY element 8 will be reset. If at this time the sectionalizing switch for some reason does not turn off the second short-circuit current surge, then the presence of two signals on the waters of element I 15 from the DTKZ 7 and REPEATER 14 elements will cause it to trip (fi d.2, diagram 26). And at its output there will be a signal that will go to RU 16. At the same time, information will appear in RU 16 that the automatic reclosure of the sectioning circuit breaker on the short circuit has failed. and its subsequent shutdown failure, and the circuit will return to the initial state of control.

If, however, an unsuccessful reclosure of a sectioning switch to a stable short circuit occurs at point 17, but its failure to disconnect does not follow, then at the end of the countdown of the protection with acceleration, the signal from the REPEATER 14 element will “reset” the MEMORY 8 element, and the circuit will also return to the initial state of control. In this case, RU 16 will reflect information on the unsuccessful reclosure of the sectioning switch.

Thus, the method allows to obtain timely information about the unsuccessful reclosure of a sectioning circuit breaker on the short circuit and its subsequent failure to shut off the power line. 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 of monitoring an unsuccessful automatic restart (AR) for a short circuit (short circuit) and the subsequent failure to disconnect the sectionalizing circuit breaker in the power line, which consists in fixing the inrush current short circuit and in measuring the time between them, characterized in that they fix the instant of occurrence of the first inrush short-circuit current at the beginning of the power line, remember it and start counting down the total time equal to the response time of the protection and the holding time of the reclosure circuit breaker, after the countdown the total time, the appearance of a second inrush fault is expected, and when the moment of fixation of the second inrush break occurs. . and at the end of the countdown of the aforementioned time, the protection operation time starts counting down with the acceleration of the sectioning switch, and if at the end of the countdown of the protection operation time with acceleration the second short-circuit current fault does not trip, then the fact of the unsuccessful reclosure on the short circuit is established. and subsequent failure to disconnect the sectioning switch in the power line.

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