RU2521968C1 - Damaged section determination method for sectionalised line of ring network - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: since tripping of a short-circuit current surge in a line of the main power supply unit the countdown is started, which is equal to the operation delay time of an automatic transfer switch (ATS). Availability of the operating current is monitored in this line, and when it is equal to zero, and at the moment of the countdown completion the operating current surge occurs in the line of the main power supply unit with the value defined by a load of this line section adjacent to the ATS point, then conclusion is made about a damage of the master section in this line, and if the operating current is not equal to zero and defined by the load connected to the master section in the line of the main power supply unit and at the moment of the countdown completion the short-circuit current surge occurs in the line of the main power supply unit, then conclusion is made about a damaged section in the line of the main power supply unit adjacent to the ATS point.

EFFECT: simplifying implementation of the method and enlarging its functional capabilities.

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Description

The invention relates to the automation of electrical networks and is intended to identify a damaged area in a sectioned line of a ring network.

There is a method for detecting selective or non-selective disconnection of a damaged section of a line, which consists in the fact that at the time of the occurrence of a short circuit current (short circuit), a probe pulse is sent to the beginning of the line, the transit time of this pulse to point KZ and vice versa is measured, and the distance from the beginning of the line to the point is calculated short circuit and determine the sectioning switch, which should be turned off, then from the moment the short circuit disappears, the short pulse is sent again, the second distance is determined, this distance is compared with the distance holes to which the sectional switches are removed from the beginning of the line, and if the second measured distance is equal to the distance to the sectioning switch that should be disconnected, then the fact of selective disconnection of the damaged section of the line is established, and if the second measured distance is equal to the distance to one of the sectional switches located before the sectioning switch, which should be turned off, the fact of non-selective disconnection of the damaged section of the line is established [patent RU No. 2402138, cl. H02J 13/00, publ. 10/20/2010, bull. No. 29].

The disadvantage of this method is the need to determine the distance to the point of damage during the passage of the inrush current by sending a probe pulse to the line.

The objective of the invention is to simplify the implementation and expand the functionality of the method by identifying a damaged area in a sectioned line of a ring network without sending probe pulses.

According to the proposed method, from the moment of the inrush current short-circuit occurring in the main power supply line, a countdown equal to the automatic standby (ABP) holding time is started, while the presence of the operating current in this line is controlled and, if it is zero, and at the time the end of the countdown in the line of the backup power source there is a surge in operating current value determined by the load of the section of the line of the main power source adjacent to paragraph ABP, then conclude that the head section of this lines, and if the operating current is not equal to zero and is determined by the load connected to the head section of the main power supply line, and at the time the countdown ends, an inrush current appears in the backup power supply line, then a conclusion is made about the damage to the section of the main power supply line adjacent to with paragraph ABP.

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 25 (see figure 1);

figure 3 - diagrams of the signals at the outputs of the elements shown in figure 1 with short circuit at point 26 (see figure 1).

The circuit (see Fig. 1) contains: a power main transformer 1 transformer, a power backup power transformer 2, busbar breakers 3 and 4, a sectional substation circuit breaker 5, a main circuit breaker of the main power supply line 6, a main circuit breaker of the backup power supply line 7, a sectioning switch of the main power supply line 8, a sectioning switch of the backup power supply line 9, a switch of the network point ABP 10, current transformers (TT) 11 and 19, a short-circuit current sensor (DTKZ) 12 and 21, Occupancy operating current (DRT) 13 and 20, 14 and NOT element 15, element MEMORY 16, delay element 17, a monostable multivibrator 18, AND gates 22 and 23, recording unit (RU) 24, points 25 and 26 kOe.

The diagrams of the signals at the outputs of the elements in case of damage to the head portion in the partitioned line of the main power source of the ring network have the form (see figure 2): 27 - at the output of element 11; 28 - at the output of element 12; 29 - at the output of element 13; 30 - at the output of element 14; 31 - at the output of element 15; 32 - at the output of element 16; 33 - at the output of element 17; 34 - at the output of element 18; 35 - at the output of element 19; 36 - at the output of element 20; 37 - at the output of element 21; 38 - at the output of element 22; 39 - at the output of element 23; 40 - in RU 24.

The diagrams of the signals at the outputs of the elements in case of damage to the line section of the main power source of the ring network adjacent to the ABP point have the form (see Fig. 3): 41 - at the output of the element 11; 42 - at the output of element 12; 43 - at the output of element 13; 44 - at the output of element 14; 45 - at the output of element 15; 46 - at the output of element 16; 47 - at the output of element 17; 48 - at the output of element 18; 49 - at the output of element 19; 50 - at the output of element 20; 51 - at the output of element 21; 52 - at the output of element 22; 53 - at the output of element 23; 54 - in RU 24.

The method is as follows.

In normal operation of the ring network, switches 3, 4,6, 7, 8, and 9 are turned on, and switches 5 and 10 are turned off. At the outputs of TT 11 and 19 there is a certain value of the output signals (Figs. 2, 3, diagrams 27, 35, 41, 49), due to operating currents, but insufficient for tripping of DTKZ 12 and DTKZ 21. From the output of the DRT 13, which only works when there is no signal when the operating current falls by a value determined by the load of the main power supply line 1 connected after the sectioning switch 8. There is no signal from the output of the DRT 20, which is triggered only when the operating current increases by a value determined by the load of the main power supply line 1 connected after the sectioning switch 8, and the circuit is in a monitoring state.

When a stable fault occurs at point 25, a signal will appear at the output of the DTKZ 12 (Fig. 2, diagram 28, time t ₁ ). This signal will go to the input of the element NOT 14 and the previously existing signal at its output will disappear (figure 2, chart 30). The short-circuit current will activate the protection of the head switch 6, and after the time delay for the operation of its protection, it will turn off and disconnect the short-circuit current. With the DRT 13, which is triggered when the operating current drops by a value determined by the load of the line connected after the sectioning switch 8, the output signal will not appear (Fig. 2, diagram 29), therefore, the output signal at the input of the And 22 element from the NOT 15 element (Fig. 2, diagram 31) does not disappear. At the time of disconnection of the inrush current KZ, the signal will appear again at the output of the element NOT 14 (Fig. 2, diagram 30, time t ₂ ). This signal will go to the input of the MEMORY 16 element, it will be remembered by it (Fig. 2, diagram 32) and will go to the input of the DELAY element 17. From the output of this element, the signal will appear after the shutter speed of the on-off switch 10 of the ABP network item and will go to the input of the SINGLE-SELECTOR 18. It will produce one oscillation (figure 2, diagram 34, time t ₃ ), this signal will “discard” the memory from element 16 and will go to the first input of the elements And 22 and And 23. At the same time, the switch 10 will turn on (previously protecting the minimum voltage of the sectioning breaker 8 disconnect t its disappearance due to voltage thereon after the head switch 6 off), and connect the core portion of the power supply 1 to the backup power supply line 2 (see FIG. 1). At the same time, at the output of the DRT 20, a signal will appear (Fig. 2, diagram 36), which will go to the third input of the And 22. element. The presence of all input signals will trigger the And 22 element (Fig. 2, diagram 38), the output signal of which will arrive in RU 24. Element I 23 will not work, because there are no input signals from the elements of the DRT 13 (figure 2, diagram 29, time t ₃ ) and DTKZ 21 (figure 2, diagram 37, time t ₃ ), therefore, information on damage to the head portion in the sectioned line will appear in RU 24 The main power source of the ring network.

When a stable fault occurs at point 26, a signal will appear at the output of the DTKZ 12 (Fig. 3, diagram 42, time t ₁ ). This signal will go to the input of the element NOT 14 and the previously existing signal at its output will disappear (Fig. 3, diagram 44). The short-circuit current will activate the protection of the sectionalizing switch 8 (see Fig. 1), and after the time for which the protection has tripped, it will turn off and disconnect the short-circuit current. At the output of the DRT 13, an output signal will appear (Fig. 3, diagram 43), which will be supplied to the second input of the And 23 element, and the output signal at the input of the And 22 element from the NOT element 15 (Fig. 3, diagram 45) will disappear. At the moment of disconnection of the inrush current KZ, the signal will appear again at the output of the element NOT 14 (Fig. 3, diagram 44, time t ₂ ). This signal will go to the input of the MEMORY 16 element, it will be remembered by it (Fig. 3, diagram 46) and will go to the input of the DELAY element 17. From the output of this element, the signal will appear after the shutter speed of the on-off switch 10 of the ABP network item (Fig. 3, diagram 47, moment of time t ₃ ) and will go to the input of the SINGLE-VIBRATOR 18. It will produce one oscillation (Fig. 3, diagram 48) and with this signal it will “discard” the memory from element 16 (Fig. 3, diagram 46) and will go to the first input of AND 22 elements and AND 23. At the same time, the switch 10 will turn on and connect the section of the main source line power supply 1 with a stable short circuit to the line of the backup power supply 2 (see figure 1). At the same time, the signal does not appear at the output of the DRT 20 (Fig. 3, diagram 50). And at the output of the DTKZ 21 signal will appear (figure 3, diagram 51, time t ₃ ). This signal will go to the third input of the And 23 element. The presence of all input signals will trigger the And 23 element (Fig. 3, diagram 53), therefore, a signal will be sent to the RU 24 and information will appear on it about damage to the section of the main power supply line adjacent to paragraph ABP (figure 3, diagram 54, time t ₃ ). Element And 22 will not work, because there are no input signals from elements NOT 15 (Fig. 3, diagram 45, time t ₃ ) and DRT 20 (Fig. 3, diagram 50, time t ₃ ). The short-circuit current will activate the protection of the circuit breaker 10 of the ABP network point and, after the delay time of the operation of its protection with acceleration, it will turn off and turn off the short-circuit current (Fig. 3, diagram 51, time t ₄ ).

Thus, the proposed method allows to identify the damaged area in the partitioned line of the ring network without sending probe pulses.

Claims (1)

A method for detecting a damaged section 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 of the short circuit (short circuit) that occurs in the main power supply line is turned off, the time starts to be counted, equal to time shutter speed automatic shutdown (ATS), while controlling the presence of a working current in this line and, if it is zero, and at the time the countdown ends, a surge appears in the line of the backup power source the operating current with a value determined by the load of the line section of the main power source adjacent to the ABP point, then conclude that the head section of this line is damaged, and if the operating current is not zero and is determined by the load connected to the head section of the main power line line, and at the moment the end of the countdown in the line of the backup power source, an inrush current appears, then they conclude that the section of the line of the main power source adjacent to the ABP point is damaged.

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