RU2414038C1 - Hold time shortening method of activation of switch of automatic load transfer (alt) at two-phase short circuit in one of sections of backup line - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: in the proposed method there controlled are all linear voltages in backup line, loss of one linear voltage in backup line is fixed, and the conclusion is made that two-phase short circuit occurred in backup line; then, loss of all linear voltages in backup line is recorded; after that, maximum hold time of actuation of network automatic reclosure is started to be reckoned. At the same time, the repeated occurrence of two linear voltages is controlled, which is determined with unsuccessful actuation of automatic reclosure to two-phase short circuit; the conclusion is made that two-phase short circuit occurred in backup line and ALT actuation signal is supplied without waiting for maximum hold time of network automatic reclosure.

EFFECT: improving accuracy of the method and simplifying its implementation owing to using only linear voltages as controlled parametre.

2 dwg

Description

The invention relates to the automation of electrical networks and is intended to reduce the time delay when transferring the consumer to a backup power source.

There is a method of reducing the time delay when transferring a consumer to a backup power source, in which the line voltage in the redundant line is monitored, as well as the voltage of the negative sequence in it, the disappearance of one linear voltage is detected, at the same time the appearance of the negative sequence voltage in the redundant line is recorded, after which concludes that on one of the sections of the reserved line a two-phase short circuit occurred (short circuit), then the disappearance of all lines 's stress in a redundant line, and then begin counting down the response time to a maximum soaking network autorecloser (APV) at the same time control the re-occurrence of the negative sequence voltage to a redundant line unsuccessful due to two-phase actuation reclosure sc one of the sectionalizing circuit breakers installed in the redundant line, record its appearance and after its disappearance conclude that as a result of an unsuccessful reclosure on a two-phase short circuit that occurred in one of the sections of the redundant line, one of the sectionalizing circuit breakers installed in the redundant the line in this case also sends a signal for the operation of the network ABP, without waiting for the maximum delay of its operation. [Patent RU 2292105 C1, IPC Н02J 9/06, published January 20, 2007, Bull. No. 2]

The disadvantage of this method is the lack of reliability of the method, the complexity of its implementation.

The objective of the proposed method is to increase the reliability of the method and simplify its implementation by using only linear voltages as a controlled parameter.

To solve this problem, in the proposed method, all line voltages in the redundant line are monitored, the disappearance of one line voltage in the redundant line is detected, a conclusion is drawn that a two-phase short circuit in the redundant line occurs, then the disappearance of all linear voltages in the redundant line is recorded, and then the count maximum exposure time of the automatic reclosure. At the same time, the re-occurrence of two line voltages due to the unsuccessful operation of the automatic reclosure for a two-phase short circuit is controlled, it is concluded that a two-phase short circuit has occurred in the redundant line and, without waiting for the maximum exposure time of the network automatic reclosure, they signal the operation of the ATS.

The essence of the invention is illustrated by drawings.

Figure 1 presents the structural diagram that implements the method.

Figure 2 presents a diagram at the outputs of the elements with a short circuit at point 23.

The circuit (see Fig. 1) contains automatic reclosure switches Q1, Q2, Q3, a switch for automatically switching on the reserve Q4, a line voltage sensor DLN5, a line voltage sensor DLN6, a line voltage sensor DLN16, element OR 8, element HE9, element DELAY 10, element MEMORY 11, OR112 element, MEMORY 13 element, OR14 element, I15 element, HE16 element, I17 element, FI18 element, MEMORY 19 element, I20 element, MEMORY 21 element, I22 element, short circuit point 23.

In case of a short circuit at point 23 (see Fig. 1), the output diagrams shown in Fig. 2 have the form: 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 - at the output of element 14; 36 - at the output of element 15; 37 - at the output of element 16; 38 - at the output of element 17; 39 - at the output of element 18; 40 - at the output of element 19; 41 - at the output of element 20; 42 - at the output of element 21.43 - at the output of element 22, 44 - at the output of element 12, 45 - at the output of element 13.

The scheme works as follows.

In normal mode, the operating current flows in the redundant line, all linear voltages are present, therefore, there are signals from the outputs of the DLN5, DLN6, DLN7 elements, respectively, there are signals from the outputs of the OR8, OR14, I15 elements, there is no signal from the HE9 element and, accordingly, from the DELAY 10 elements, OR 12, HE16 there is also no signal from the I17 element and, accordingly, there is no signal from the elements FI 18, I20, I22. Since all linear voltages are present, accordingly, there is a signal from the And15 element. The signal from the I15 element is sent to the reset of the MEMORY 11, MEMORY 13, MEMORY 19, MEMORY 21 elements.

The circuit does not start.

The operation of the ATS with maximum time delay when the voltage disappears in the redundant line is provided as follows.

At the time of the occurrence of a two-phase short circuit at point 19, one line voltage disappears, which leads to the disappearance of the signal from the output of the DLN5 element (figure 2, diagram 26), and accordingly the signal from the element And 15 disappears (figure 2, diagram 36). Thus, the reset signal disappears from the MEMORY elements 11, 13, 19, 21. Since two other line voltages are present in the reserved line at this moment, there is a signal at the input of the OR8 element (Fig. 2, diagram 29). After disconnecting the short circuit by the switch Q2, the signal from the OR element 8 disappears (Fig. 2 diagram 29), a signal appears on the element NOT 9 and is fed to the input of the DELAY 10 element, at the input of which the signal appears after a time equal to the maximum delay time of the automatic reclosure .

This time takes into account the longest dead time of automatic reclosure, sectionalizing circuit breakers installed in the redundant line. The signal from the output of the DELAY element 10 is fed to the input of the MEMORY element 11, the signal arriving at the input of the OR element 12 will appear at its output (Fig. 2, diagram 32). The signal from the OR12 element is fed to the input of the MEMORY 13 element (FIG. 2 diagram 33), a signal appears on the input of this element, which turns on the network ABP (FIG. 2 diagram 34).

If during the time specified in the DELAY 10 element a successful automatic reclosure of one of the switches occurs, then all the line voltages in the redundant line will be restored, accordingly a signal will appear from the And 15 element, which will be sent to reset the MEMORY 11 and 13 elements, as a result why the inclusion of ATS will not happen.

Reducing the response time of the network ABP is as follows.

At the moment of a two-phase short circuit at point 19, one line voltage disappears, which leads to the disappearance of the signal from the output of the DLN element 5 (figure 2, diagram 26), and accordingly the signal from the element And 15 disappears (figure 2, diagram 36), respectively the signal on the element is NOT 16 (figure 2 diagram 37). Thus, the reset signal disappears from the MEMORY elements 11, 13, 19, 21. Since at this moment two other line voltages are present in the reserved line, there is a signal at the input of the OR14 element (Fig. 2, diagram 35). This signal is fed to one of the outputs of the And 17 element, the signal is supplied to the other output from the HE 16 element, and accordingly, a signal appears at the input of the And17 element, which is fed to the FI18 element (Fig. 2, diagram 38). The FI18 element generates a signal when the signal disappears at its input, that is, at the output of the FI18 element, the signal (Fig. 2 diagram 39) appears at the moment the signal disappears from the OR14 element. This occurs when one of the sectional switches Q1 or Q2 is turned off due to a short circuit at point 19. The signal from the output of the FI18 element is stored by the MEMORY 19 element and fed to one of the inputs of the I20 element (Fig. 2 diagram 40) at this time on the other input of the element And 20 signal is absent, since there is no signal from the element OR14. After a certain dead time, the reclosure of one of the sectioning switches occurs, as a result of which, if a two-phase short circuit is stable, one line voltage will disappear again in the redundant line. There will be signals on the elements OR 14 and AND 17. The signal from the elements OR 14 and NOT 16 is fed to the input of the element And 20. At the output of the element And 20 a signal will appear (figure 2 diagram 41), which is stored by the element MEMORY 21 and fed to one of the inputs of the element And 22, at the second input of which a signal appears from the element NOT 9 when the voltage in the redundant line disappears after one of the sectional switches is turned off. At the output of the AND element 22, a signal appears (Fig. 2, diagram 43), which arrives at the input of the OR element 12 earlier than the other output receives a signal from the MEMORY element 11. The signal from the OR element 12 is fed to the memory element MEMORY 13 (Fig. 2 diagram 44), at the input of this element a signal appears (figure 2 diagram 45), which includes a network ATS. In this case, the network ABP is turned on earlier than during the operation of the circuit with the maximum delay of its operation, as follows from diagrams 34 and 45 of FIG. 2.

If the two-phase short circuit at point 19 is unstable and resolves itself during a current-free pause, in this case, the automatic reclosure of one of the sectionalizing switches will occur. In this case, all linear voltages in the redundant line will be restored, accordingly, a signal will appear from the output of the And 15 element, which will work to reset the MEMORY 11, 13, 19, 21 elements, respectively, the signal will not be sent, as a result of which the ATS will not turn on.

Thus, the reliability and simplicity of the implementation of the method is increased, due to this, the response time of the network ABP during a two-phase short circuit in one of the sections of the redundant line is reduced, which increases the efficiency of power supply to consumers by reducing the time of interruptions in their supply of electric energy.

Claims (1)

A method of reducing the shutdown time of the automatic transfer switch (ATS) switch during a two-phase short circuit in one of the sections of the redundant line, which consists in monitoring the voltages in the redundant line, characterized in that the linear voltages in the redundant line are controlled, the disappearance of one linear voltage is detected, and the conclusion is made that in one of the sections of the redundant line a two-phase short circuit occurred, after which the time delay of the operation of the network ATS starts, at At the same time, the repeated occurrence of line voltages in the redundant line is controlled due to the automatic re-activation (AR) of one of the sectionalizing circuit breakers installed in the redundant line, they detect the absence of one line voltage and conclude that as a result of the unsuccessful operation of the automatic reclosure on a two-phase short circuit, occurred on one of the sections of the redundant line, one of the sectionalizing switches installed in the redundant line was disconnected, in which case give a signal to actuate the ATS network, without waiting for the countdown maximum exposure time of its operation.

Images