RU1814137C - Device for protection of electric power lines - Google Patents

Abstract

The invention makes it possible to provide long-term redundancy of the backup and primary protection of power lines with high-frequency blocking for any types of short circuit on the branch. Usage: an increase in speed and sensitivity is achieved by starting the reverse sequence from the current relay and self-holding the time relay and starting the transceiver on each side of the power transmission line. 2 ill.

Description

The invention relates to electrical engineering, to devices for high-frequency (including) protection of power lines for redundant protection of connected branches.

The purpose of the invention is to increase the speed of the main protection and the sensitivity of the backup line protection when equipped with RF protection for the universality of their operation.

Figure 1 shows a structural diagram of a half-set of protection of power lines with a branch; figure 2 is a diagram of the operational circuits of the backup protection of power lines with high-frequency lock.

The device for protecting the power line contains, on each side of the line, a main rf unit 1. protection, consisting of measuring and logic elements connected at the input to current transformers 2 of line 3 with branch 4 and to voltage transformers 5 of substation 6, to which line 3 is connected via switch 7, to the disconnection circuit of which the output of unit 1 is connected. K line 3 connected organ 8 v.h. - processing, which is connected to the transceiver 9, the start-up circuit of which is connected from the output of unit 1, as well as from the output of the power relay 10 connected to the measuring transformers 2 and 5, together with the time relay 11, the start-up circuit of which is connected to the reverse sequence current relay 12, connected to current transformers 2 of line 3. A reacting organ 13 is connected to the output of transceiver 9, the output of which is included in the circuit of block 1 and in the self-holding circuit of time relay 11, the output of which is included in the disconnection circuit of switch 7 of line 3 (Fig. 1).

Between the positive and negative output terminals of the operational circuits. The protection is connected to the coil 14 of the time relay 11 through the NO contacts 15 of the relay. Reverse sequence current 12. The disconnection circuit of the switch 7 is connected to the positive terminal through the first NO contacts 16 of the timer 11,

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and its temporarily closing contacts 17 together with the closing contacts 18 of the power direction switch 10 are included in the start-up circuit of the transceiver 9. The self-pick-up circuit of the time relay 11 is connected through its own instantaneous closing contact 19 and the resistor 20, as well as through the relay switching contact 21 with time delay time 11 with separately connected opening contact 22 and closing contact 23 of the reacting organ 1.3 of the transceiver 9. In parallel to the coil 14 of the time relay 11, a capacitor 24 is connected, as well as a circuit from the second closing with a time delay of contact 25 of the time relay 11 and the breaking contact 26 of the reverse sequence current relay 12 (FIG. 2).

The device operates as follows.

With an external short circuit of the outflow in line 3 through the current transformer 2, the reverse sequence current relay 12 is activated with the contacts 15 of the power supply circuit of the coil 14 of the time relay 11 closed and disappears after the short circuit current is stopped, because its self-retention does not occur due to the open state of the contacts 22 of the reacting organ 13 of the transceiver 9, which receives the RF signal through the RF processing organ 8 from the transmitter of one or three sides of the protected power transmission line. . .

Contact time-switching contact 21 has a setting tn more at the selectivity level Atci with respect to the duration of the protection of the backup transformer 4 tp3,

those. Atci

The self-holding circuit through the instantaneous make contact 19 and the resistor 20 is maintained only if the power flow from both sides of the line is directed from the buses b to line 3 and after the specified setting tp3, i.e. when short circuit is stored behind branch transformer 4 due to failure of its protection.

Together with the transfer of contacts 21 of the time relay 11, contacts 17 of the same relay are closed on the first side of the line, 3 with the start of the transceiver 9 when the contacts 18 of the power direction switch 10 from the current of the current transformer 2 and the voltage of the voltage transformer 5 are closed due to the power flow to the line 3 with time. The closed contact interval of the contacts 17 is set higher than the error of the relay equipment,

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5

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5

0

5

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5

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5

those. Ati tnorp. The closure of the contacts 17c of the opposite side of the power transmission line is established with the time Ati, and the interval of their closed state is chosen similarly, i.e. At2 Ati.

As a result, the transmitter is first launched on the first side of the power transmission line, and then on the opposite side, provided that there are power flows on the line from the buses of both reference substations when the short circuit is not disconnected on the branch of the protected power line. The contact 23 is closed from receiving the RF signal first from the transmitter of its side, and then from the opposite side of the power transmission line, thereby maintaining the self-locking of the time relay, which before switching contacts 21 occurred due to the closed state of the contacts 22 due to the absence of -no Power lines of RF signals until the moment of switching the self-pickup circuit during short circuit in the protection zone of power lines. The duration of switching contacts 21 is set within the interval equal to twice the value of the closing time of the transmitter starts, i.e. At2, In this case, the capacitor1 24 provides a delay for the falling off of the time relay with an error in the counting of the settings of the relay of the self-holding circuit, i.e. TV 1Go, TV Ati. With the subsequent selectivity step Atc2 tnorp, the contacts 16 of the time relay 11 are closed to turn off the switch 7 with the general setting toro tp3 + A tc + + Atn + Ate-After the switch is turned off by the contacts 25, the time relay 11 removes the self-pickup, because the contacts 26 of the reverse sequence current relay 12 are already in a closed state, due to which the circuit returns to its original position with a time of 1 return 1 off + At1.

The described sequence of operation of the equipment of the power transmission line protection circuit corresponds to the most frequent occurrence of interphase short circuit branches on the transformer with its subsequent transition to a symmetric three-phase short circuit. While maintaining an asymmetrical phase-to-phase short circuit, the need for a self-pickup circuit disappears and the time relay 11 remains in the raised position from the contacts 15 of the reverse sequence relay 12, which are constantly closed during short circuit.

The disconnection of the switch 7 without time delay occurs when a fault on line 3 from the operation of block 1 of the main r.h. protect power lines.

As a result, due to the mutual control of the power flow on the power transmission line, both immediate short-circuiting of the short circuit on the protected line and its operation as a backup for any type of short-circuit on the branch in the event of failure of the protection of the transformer of the branch are ensured, which significantly increases the reliability of the network and connected to it transformer substations due to the universality of the applied power line protection.

Claims (1)

SUMMARY OF THE INVENTION A device for protecting a power line, comprising, on each side, a main high-frequency protection unit, including a measuring-organ connected in series, a transceiver with a reacting organ, and a high-frequency processing organ, the input terminals of the measuring organ are connected to the sensors current and voltage of the line, output terminals are intended to be connected to the trip circuit of the corresponding line switch, the second terminal of the high-frequency processing organ and is intended to be connected to the line wire, and a backup protection unit made in the form of a reverse sequence current relay connected to the line current sensor, the closing contact of which is connected in series with the time relay winding between the positive and negative terminals of the power supply of the operational protection circuits, relays of time has an instantaneous make contact and the first make contact with time delay, one terminal of the latter is connected to the positive terminal of the power supply of the operational protection circuits, and d The other terminal is intended for connection to the circuit breaker circuit breakers, characterized in that, in order to improve performance and of sensitivity, the redundant protection unit is additionally connected to the current and voltage sensors of the power direction switch line with a closing contact, a time-delay switching, a time-closing and a second time-closing contact of a time relay, a closing and opening contact of a transceiver reacting organ, a breaking contact of a relay reverse sequence current, a resistor and a capacitor connected in series, while between the terminals of the power supply of the operational protection circuits The fixed output and the closing output of the switching contact of the time relay, the making contact of the reacting organ of the transceiver, the instantaneous making contact of the time relay, the resistor and capacitor, the opening output of the switching contact of the time relay through the opening contact of the reacting organ of the transceiver are connected to the first output of the instantaneous making contact time relay, sequentially connected second contact with time delay contact time relay and NC contacting the negative sequence current relay winding connected in parallel time switches and a capacitor to the positive terminal of power supply for operating circuits connected serially connected protection make contact power relay directing and temporarily closing contact time switch, the second terminal of the latter is intended for connection in the starter circuit of the transceiver. Dk /; Qfat.