RU2551380C1 - Control method for successful and unsuccessful automatic reclosure of circuit breakers and determining type of short circuit in sectionalised line of ring network - Google Patents

Abstract

FIELD: electricity.SUBSTANCE: invention is intended to control successful and unsuccessful automatic reclosure of circuit breakers and determining type of short circuit in the sectionalised line of ring network supplied by different buses of the two-transformer substation. Since the moment of fault current surge at the substation busses the countdown time is started as a period equal to delay in actuation of each circuit breaker installed in the sectionalised line; at that availability of fault current and moment of its disappearance is monitored in all line phases and if fault current disappears at the moment of the above delay time ending and if it passed through two phases then the tripped circuit breaker is set for two double-phase fault, and if it passed through three phases then tripped circuit breaker is set for two three-phase fault; since the moment of fault current surge the second countdown time is started as a period equal to automatic reclosure of the tripped circuit breaker, at that occurrence of the second current surge is monitored, and if it appears at the moment of the second delay time ending with a value bigger than the rated operating current and less then fault current and fault current passed through two phases then successful automatic reclosure of the tripped circuit breaker upon self-cleared double-phase fault is stated or successful automatic reclosure of the tripped circuit breaker upon self-cleared three-phase fault is state if fault current passed through three phases; and if at the moment of the delay time ending for the tripped circuit breaker the second surge of fault current occurs and fault current passes through two phases and upon delay time with acceleration it trips then conclusion is made about unsuccessful automatic reclosure of the tripped circuit breaker at double-phase fault or if fault current appears and passes through three phases and the circuit breaker trips upon delay time with acceleration then conclusion is made about unsuccessful automatic reclosure of the tripped circuit breaker at three-phase fault.EFFECT: expanding functionality by receipt of information about successful and unsuccessful automatic reclosure of circuit breaker with determination of fault type in the sectionalised line of ring network.9 dwg

Description

The invention relates to the automation of electrical networks and is intended to control the successful and unsuccessful automatic restart (AR) of circuit breakers with determining the type of short circuit (SC) in a sectioned line of a ring network powered by different buses of a two-transformer substation. Moreover, the line circuit breakers are equipped with single-action reclosure devices and have different protections.

A known method of monitoring the successful and unsuccessful reclosure of circuit breakers in a sectioned line of a ring network powered by two-transformer substation buses is that from the moment of a surge current in the beginning of a sectioned line of a ring network, the time equal to the response time of the protection of each switch installed in a sectioned circuit is counted lines. At the same time, the time of the short circuit current inrush is controlled and, if the moment of the end of the countdown, the response time of the protection of one of the circuit breakers coincides with the moment of the short circuit current inrush is disconnected, the disconnected switch is determined. Further, from the moment of switching off the first inrush short-circuit current, a countdown starts equal to the AR time of the open circuit breaker, while the appearance of the second inrush current is controlled and if, when it appears at the end of the AR time of the open circuit breaker, it is greater than the normal operating current, but less than the current Short circuit, then I establish the fact of a successful reclosure of a tripped circuit breaker, and if it is greater than or equal to the short-circuit current of an unsuccessful reclosure of a circuit breaker installed in a partitioned line of a ring network [p Atent No. 2305356 C1, class H02J 13/00, publ. 08/27/2007, bull. No. 24].

The disadvantage of this method is the impossibility of using it to control the successful and unsuccessful reclosure of circuit breakers with determining the type of fault in the partitioned line of the ring network.

The objective of the invention is to expand the functionality of the method by obtaining information about the successful and unsuccessful reclosure of circuit breakers with determining the type of short circuit in the partitioned line of the ring network.

According to the proposed method, from the moment of the appearance of a short-circuit current surge on the substation tires, a countdown starts equal to the response time of the protection of each switch installed in the partitioned line, while the presence of the short-circuit current and the moment of its disappearance is monitored in all phases of the line and, if the short-circuit current disappears the end time of the response time of the protection of one of the switches and flowed in two phases, then set the disconnected switch when two-phase fault, and if the short-circuit current flowed in three phases, then in three phases Mr. Short circuit, from the moment of switching off the inrush current, the short circuit starts the second countdown equal to the holding time of the automatic reclosure circuit breaker, while controlling the appearance of the second inrush current and, if it appears at the end of the second counting time, is greater than the normal operating current, but less than the short circuit current and if the short-circuit current flowed through two phases, then the fact of a successful reclosure of a tripped circuit breaker after a self-resetting two-phase short circuit is established or the fact of a successful reclosure after a self-resetting three-phase short circuit is established if the short-circuit current flows through three phases m, and if at the end of the countdown of the automatic reclosure time of the tripped circuit breaker, a second short-circuit current surge occurs, flowing in two phases, and after the protection is tripped with acceleration, it turns off, then a conclusion is made about the automatic reclosure of the circuit breaker with a two-phase short circuit or if the short circuit current appears, proceeds in three phases, and after the time the protection is tripped with acceleration is turned off, they conclude that the automatic reclosure of the disconnected circuit breaker with a three-phase short circuit is unsuccessful.

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 a short circuit at point 5 and a successful automatic reclosure SV 4 (see figure 1);

- figure 3 diagrams of the signals at the outputs of the elements shown in figure 1 with a two-phase short circuit at point 5 and the unsuccessful reclosure SV 4 (see figure 1);

- figure 4 diagrams of the signals at the outputs of the elements shown in figure 1 with a three-phase short circuit at point 5 and a successful reclosure SV 4 (see figure 1);

- figure 5 diagrams of the signals at the outputs of the elements shown in figure 1 with a three-phase short circuit at point 5 and the unsuccessful reclosure SV 4 (see figure 1);

- figure 6 diagrams of the signals at the outputs of the elements shown in figure 1 with a two-phase short circuit at point 3 and a successful reclosure HW 2 (see figure 1);

- Fig.7 signal diagrams at the outputs of the elements shown in Fig.1 with a two-phase short circuit at point 3 and the unsuccessful reclosure HW 2 (see Fig.1);

- in Fig. 8, the signal diagrams at the outputs of the elements shown in Fig. 1 with a three-phase short circuit at point 3 and successful reclosure HW 2 (see Fig. 1);

- figure 9 diagrams of the signals at the outputs of the elements shown in figure 1 with a three-phase short circuit at point 3 and the unsuccessful reclosure HW 2 (see figure 1).

The circuit (see figure 1) contains: power transformers 1 and 10; head switches (GV) 2 and 8; KZ points 3 and 5; sectionalizing switches (CB) 4 and 7; switch 6 of the network point automatically turn on the reserve (ABP); sectional switch 9; short circuit current sensors (DTKZ) 11, 12 and 13; working current sensor (DRT) 14; SINGLE VIBRATORS 31 and 46; elements OR 15, 16, 32 and 49; elements 17, 19, 24, 28, 33, 34, 35, 36, 43, 45, 49, 50, 51, 52 and 53; elements NOT 18, 22 and 39; MEMORY elements 20, 37 and 47; elements FORBIDDEN 21, 26, 38 and 42; time delay units (BVV) 23, 25, 27, 30, 40, 41, 44 and 48; recording devices (RU) 54.

The signal diagrams of the elements shown in figure 1 have the form (see figure 2): 55 - at the output of element 11, 56 - at the output of element 12, 57 - at the output of element 13, 58 - at the output of element 14, 59 - the output of element 15, 60 - at the output of element 16, 61 - at the output of element 17, 62 - at the output of element 18, 63 - at the output of element 19, 64 - at the output of element 20, 65 - at the output of element 21, 66 - at the output element 22, 67 - at the output of element 23, 68 - at the output of element 24, 69 - at the output of element 25, 70 - at the output of element 26, 71 - at the output of element 27, 72 - at the output of element 28, 73 - at the output of the element 29, 74 - at the exit of the ele Enta 30, 75 - at the output of element 31, 76 - at the output of element 32, 77 - at the output of element 33, 78 - at the output of element 34, 79 - at the output of element 35, 80 - at the output of element 36, 81 - at the output of the element 37, 82 - at the output of element 38, 83 - at the output of element 39, 84 - at the output of element 40, 85 - at the output of element 41, 86 - at the output of element 42, 87 - at the output of element 43, 88 - at the output of element 44 , 89 - at the output of element 45, 90 - at the output of element 46, 91 - at the output of element 47, 92 - at the output of element 48, 93 - at the output of element 49, 94 - at the output of element 50, 95 - at the output of element 51, 96 - at the output of element 52, 97 - at the exit de element 53, 98 - in RU 54.

In addition to the diagrams of the output signals, FIGS. 2, 3, 4, 5, 6, 7, 8, and 9 also show: t ₁ - the instant of occurrence of the fault current, t ₂ - the instant of operation of the protection CB 4, t ₃ - the instant of operation protection of hot water supply 2, t ₄ - time instant of repeated switching on of CB 4, t ₅ - time instant of repeated switching off with acceleration of CB 4, t ₆ - time instant of repeated switching on of hot water 2, t ₇ - instant of time of repeated switching off with acceleration of hot water 2.

The method is as follows.

In normal operation of the ring network, switches 2, 4, 7, and 8 are turned on, and switches 6 and 9 are turned off. There are no signals at the outputs of the DTKZ 11, 12, and 13 (Fig. 2, diagram 55, 56, 57, time t ₀ ), therefore, the circuit is in control mode.

When a two-phase fault occurs, for example, at point 5, signals will appear at the outputs of the DTKZ 11 and 12 (Fig. 2, diagrams 55 and 56, time t ₁ ) they will go to the inputs of the OR elements 15 and 16, so the signals will appear at their outputs (Fig. 2, diag. 59 and 60), as well as the first and third inputs of the element And 17. In this case, the presence of only two input signals on the element And 17 and the absence of a third input signal will ensure the absence of a signal at the output of this element (Fig. 2 , Fig. 61) and will ensure the presence of an output signal already existing before that on the element NOT 18 (Fig. 2, Fig. 62) which As well as the output signals from the OR elements 15 and 16 will go to the inputs of the And 19 element, it will work, therefore, at the output of this element will appear its own signal (Fig. 2, Diagram 63), which will go to the input of the elements BAN 21, NOT 22 and the second inputs of the elements And 34 and 35, while the existing output signal from the element NOT 22 will disappear (figure 2, Fig.66). The signal from the element PROHIBIT 21 (Fig. 2, Diagram 65) will go to the inputs of the BVV 23 and 25, from the output of the BVV 23 the signal will appear after a time equal to the response time of the protection CB 4 (Fig. 2, Diagram 67), and BVV 25 output signal will appear after the exposure time of the protection of the GV 2 protection, which according to the selectivity condition is longer than the exposure time of the protection of CB 4. Therefore, the output signal of the BVV 25 (Fig. 2, Diagram 69) will go to the BAN 26 element, but at the output will not appear (figure 2, diag. 70) since at the prohibitory input of this element there will be a signal from the element MEMORY 29 (Fig. 2, Diagram 73). The signal from CB 4 will go to the first input of AND elements 24, to the input of the MEMORY 20 element, it will be remembered by it (Fig. 2, Diagram 64) and will go to the inhibitory input of element 21 and will prevent the signal from passing when the CB 4 is switched back on to short circuit. At the second input of element 24, the signal will come from element NOT 22, because at this moment in time (t _2, see Fig. 2), CB 4 will turn off, therefore, the signal will appear again at the output of NOT 22 (Fig. 2, Fig. 66). The presence of two input signals will ensure the appearance of the output signal on the element And 24 (figure 2, Fig. 68). This signal will go to the input of the BVV 30 and the input of the element MEMORY 29, where it will be remembered by it (Fig. 2, Diagram 73) and will go to the inhibitory input of the element 26. This will ensure that the signal will not pass from the element of the BVV 25. By this time, the signal will not exit from it, because the time delay of element 23 is less than that of element 25. From the output of the BVV 30, the signal will appear after a time equal to the exposure time of the automatic recycle gun CB 4 and will go to the first inputs of the elements And 33 and 34. At this point in time (t ₄ see figure 2) will occur Auto-reclosure SV 4. And if during the exposure time, automatic reclosure SV 4 KZ eliminates itself, then at the output of the DRT 14 a signal will appear (Fig. 2, diagram 58), which will go to the second input of the And 33 element and ensure that the signal appears at its output (Fig. 2, Fig. 77), which, having entered RU 54, will provide information on it about the successful automatic reclosure of SV 4 after a two-phase fault (Fig. 2, Fig. 98). Also, this signal will go to the input of the OR 32 element, and from its output to the MEMORY 20 element and “reset” it (Fig. 2, Diagram 64). And if during the exposure time of the automatic reclosure, the CB 4 short circuit did not settle down and turned out to be stable, then with the reclosure AR 4 the short-circuit current appears again and the output signal appears on the I 19 element (Fig. 3, Diagram 63), which will go to the input of the BAN 21 element, but it will not appear on its output, as at its prohibitory input there will be a signal (Fig. 3, Diagram 65), it will also go to the input of the element NOT 22, while its output signal will disappear again (Fig. 3, Diagram 68), and it will also go to the second input of the And element 34 and will ensure the appearance of its output signal (Fig. 3, Fig. 78). This signal will go to RU 54 and there will appear information about the unsuccessful reclosure of SV 4 with a two-phase short circuit (Fig. 3, Fig. 98). Also, the signal of the And 34 element will go to the input of the OR 32 element, and from its output (Fig. 3, Diagram 78) to the MEMORY 20 element and "reset" it (Fig. 3, Diagram 60). If at point 5 not three-phase, but three-phase short-circuit occurs, then at the outputs of DTKZ 11, 12 and 13 signals will appear (Fig. 4, diag. 55, 56 and 57). These signals will go to the inputs of the OR elements 15, 16 and the AND element 17. At the same time, all the outputs of these elements will receive signals (Fig. 4, Diagrams 59, 60, and 61) that will go to the first and second inputs of the And 19 element and to the input of the element is NOT 18. In this case, the signal will disappear from the output of this element (Fig. 4 diag. 62), therefore, the And 19 element will not work, because there will be only two signals at its input. However, the signal that appears at the output of the AND 17 element will go to the inputs of the BAND 38, NOT 39 elements and to the first inputs of the AND 51 and 52 elements. From the output of the BAN 38 element, the signal (Fig. 4, Diagram 82) will go to the input of the BVV 41 , and from the output of this element, the signal will appear after a time equal to the response time of the protection of CB 4 (Fig. 4, Diagram 85), and will go to the first input of the And 45 element. At this time, CB 4 will turn off and the output signal will appear again element NOT 39 (Fig. 4, Diagram 83). And 45 will work, its signal (Fig. 2, Diag. 89) will go to the input of the MEMORY element 47, will be remembered by it (Fig. 2, Diag. 91) and will go to the inhibitory input of element 42 and will prevent the signal from passing from element 40. Also, the signal from the And 45 element, it will go to the input of the BVV 48 element, it will be delayed in it for the duration of the automatic reclosure shutdown CB 4 and will go to the second inputs of the And 50 and 51 elements. At this point in time (t ₄ ), if the short circuit at point 5 is eliminated, then CB 4 successfully re-enable, while the output of the DRT 14 will receive a signal (figure 2, diagram 58). It will go to the first input of the And 50 element and it will work (Fig. 2, Diagram 94). The output signal of this element will go to the OR element 49, and from this element (Fig. 4, Diag. 93) it will go to the MEMORY element 37 and "reset" it (Fig. 4, Diagram 81). Also, the signal from the And 50 element will go to RU 54 and information on the successful automatic reclosure of SV 4 after a three-phase fault will appear in it (Fig. 4, Diagram 98). And if by the time t _{4 the} short circuit at point 5 does not resolve itself, then CB 4 will turn on the short circuit, the short circuit current will appear again (Fig. 5, diagram 55, 56, 57). The output signals will appear on the elements OR 15 and 16, AND 17 (Fig. 2, Diagrams 59, 60 and 61) and the signal from the element NOT 18 will disappear (Fig. 5, Diagram 62). The signal from the element And 17 will go to the first input of the element And 51 and it will work (figure 5, Fig. 95). Its signal will go to the OR element 49, and from its output (Fig. 5, Diagram 93) to the MEMORY 37 element and "reset" it (Fig. 5, Diagram 81). Also, this signal will go to RU 54 and there will appear information about the unsuccessful reclosure of SV 4 with a three-phase short circuit (Fig. 5, Diagram 98).

If a stable or unstable two-phase or three-phase short circuit occurs not at point 5, but at point 3, then the operation of the circuit will occur similarly to the work described above, while the output signal diagrams of the circuit elements during successful or unsuccessful reclosure of AR 2 when two-phase or three-phase short circuit will be have the form shown in Fig.6, 7, 8 and 9.

Thus, when using the proposed method, it is possible to obtain information about the successful or unsuccessful reclosure of circuit breakers with determining the type of fault in the partitioned line of the ring network.

Claims (1)

A method for monitoring successful and unsuccessful automatic restart (AR) of circuit breakers with determining the type of short circuit (SC) in a sectioned line of a ring network, which consists in fixing the inrush currents and in measuring the time between them, characterized in that from the moment the inrush current appears on the buses substations start a countdown equal to the response time of the protection of each circuit breaker installed in the partitioned line, while the presence of short-circuit current and the moment of its disappearance are monitored in all phases lines and, if the short-circuit current disappears at the end of the tripping time of the protection of one of the circuit breakers and flows in two phases, then the circuit-breaker is installed in case of a two-phase short circuit, and if the short-circuit current flows in three phases, then in a three-phase short circuit, from the moment the inrush trip short-circuit current starts the second countdown, equal to the AR time of the tripped circuit breaker, while controlling the appearance of the second inrush current and if it appears at the end of the second countdown the value is greater than the normal operating current, but more than the short-circuit current and the short-circuit current flowed in two phases, then establish the fact of a successful reclosure of a tripped circuit breaker after a self-resetting two-phase short circuit or the fact of a successful reclosure after a three-phase short circuit self-resetting, if a short-circuit current flowed in three phases, and if at the end of the countdown time of the reclosing circuit breaker a second short-circuit current surge occurs, flowing in two phases, and after the protection has tripped with acceleration, it turns off, then a conclusion is made about the unsuccessful reclosure of a tripped circuit breaker with a two-phase short circuit and whether if a short-circuit current appears, flows through three phases, and after a time of holding the protection trips with acceleration it turns off, then a conclusion is made about the unsuccessful reclosure of a tripped circuit breaker with a three-phase short-circuit.

Images