SU477499A1 - Device for relay protection of parallel power lines - Google Patents

Description

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Body diodes 28 with blocking inputs 3 and 4 transmitters 5.

The election authority 25 compares the absolute values of the currents of the reverse parallel lines. With external short-circuits, the x currents in parallel lines are almost insignificantly different from each other. In the event of a short circuit on one of the lines, the reverse sequence current at least at one of the ends of this line exceeds the current in the intact line.

The electoral authority has two outputs, and in the event of a short circuit on a particular line, a signal appears on one of them, corresponding to a damaged line. In case of a short circuit at the beginning of the line, the selective authority of the protection kit installed at the opposite end does not work, since the currents in the lines at this end are almost the same. Therefore, the proposed device provides for the use of separate permitting and blocking high-frequency signals for each line.

In the case of an asymmetrical short circuit, the triggering unit 1 of the protection device is triggered on one of the parallel lines, and signals appear on its tripping outputs. If the magnitude of the fault current is insignificant, then the signal can occur only at the sensitive disconnecting output (either in one or in both semi-sets). At the same time, the comparator 25 is triggered at the output of its corresponding to the damaged line, a signal appears that goes to one of the blocking inputs, for example, to input 3, of the transmitter 5, ensuring the start of the blocking high-frequency signal corresponding to the intact line. In addition, the signal from the output of the body 25 is supplied to the additional disconnecting input 26 of the block 6 of the damaged line and to the prohibiting input 27 of the block 7 of the intact line. Since the blocking signal from output 12, corresponding to the damaged line, is absent, a signal appears at the shutdown output of block 6, which is fed to the actuator 19.

At the prohibitory input 27 of block 6, the signal from the output of the organ 25 is absent, therefore it passes the signal from the sensitive disconnecting output of the starting unit 1 to the start of the enabling high-frequency signal 17 corresponding to the damaged line and to disconnecting the line through the circuit controlling the availability of the enable signal on the opposite end of the line.

At the same time the signal from the output of the body 25 is fed to the prohibiting input 27 of the block 7 of the intact line. The signal from the sensitive output of the starting block 1 does not pass to the start of the enabling signal 18,

corresponding to this line, and to disconnect the line along the circuit, which controls the presence of an enabling signal from the other half-set.

If, at a short circuit at the beginning of the line, the comparison unit 25 of the protection half-set does not work, then the correct action of the protection is ensured by the fact that the protection half set closest to

to the place of damage, does not send a permitting signal corresponding to the intact line, and disconnection of the line through the circuit controlling the absence of the blocking signal is possible only when triggered to the appropriate side of the reference organ.

In case of external short circuits, one of the half-sets sends blocking signals for both lines and does not send enabling signals, which ensures blocking of protection.

The triggering of one or another blocking signal when a reference element is triggered is necessary to prevent the intact line from shutting down during a short circuit to

another line in its one-way mode.

The action of protection in case of short circuits on one of the lines in the mode of its one-sided connection is provided by the body 22 of the one-sided turn on of the line, body 21

monitor the presence of line voltage and

by starting the blocking signal when turned on

lines.

Prevent false job protection for

The counting of the time-consuming switching phases of the switch when the line is turned on is provided by slowing it down with the help of a signal from bodies 21 and 22 to the inhibit inputs of blocks 6 and 7, respectively.

The reverse sequence power unit 24 is required to block protection in the event of short circuits on the lines, if the ratios of the quantities being compared may correspond to a short circuit on the line.

With symmetrical short circuits, the protection must respond to the appearance of transient asymmetry.

Subject invention

A device for relay protection of parallel transmission lines, made in the form of semi-sets installed at the ends of the line and connected by a high-frequency channel, each of which consists of a starting unit, blocking the output of which through dividing diodes is connected to two blocking inputs of the transmitter, and two

control units of the transmitter and the formation of a tripping signal, the corresponding inputs of which are connected to the tripping outputs of the starting unit and the outputs of the receiver, and the corresponding outputs to

the inputs of the transmitter and the executive body, characterized in that, in order to increase reliability and sensitivity, all semi-komplekty contain an organ comparing the absolute values of the negative sequence of currents of parallel lines with two outputs, each of which

connected to the additional disconnecting input of one control unit and to the additional inhibitory input of another control unit, as well as through an isolation diode with a corresponding blocking input of the transmitter.

/ 2U7 Needles, 1111