SU1134082A1 - Method of standby protection of line with tapped transformers - Google Patents

Abstract

A DEVICE FOR A BACKUP PROTECTION OF A LINE WITH EMPTY TRANSFORMERS, containing transformers and voltages connected to a current filter protection unit, the output of which is connected to a disconnecting unit consisting of a time relay, which is connected to the output contacts of the unit, which is connected, and the drives are connected, and the drives are connected, and the drives are connected, and the drives are connected to the outgoing contacts of the unit, which are connected, and the drives are connected, and the drives are connected, and the drives are connected. The time contacts of the time relay are included in a circuit breaker trip circuit, characterized in that, in order to increase the sensitivity to three-phase short circuits, switching from two-phase circuits, phase-sensitive blocks are inserted in the active and reactive components respectively of the tbka line, two delay blocks, two comparison blocks, maximum and minimum relays, the inputs of the phase-sensitive blocks connected to current and voltage transformers, the output of the phase-sensitive block separating the reactive component of the current connected to the inputs of the first the comparator unit directly and through the first delay unit, the output of the phase-sensitive active component component of the current component is connected to the inputs of the second unit In the comparison, directly and through the second delay unit, the outputs of the first and second comparison units are connected respectively to the maximum and minimum relays whose outputs are connected to the disconnecting unit, and in the disconnecting unit in parallel to the first time relay contacts connected to the time relay connected second closed with time delay time relay contacts, short circuit contacts of the minimum relay and the closing contacts of the maximum relay, while parallel but the contacts of the relay included in the time relay coil circuit connected zamykayuschies without time: the time the contacts time relay and time relay winding shunted about. chain of successively connected third ones; contact with time relay contact time relay and expanding output contacts TOB protection block.

Description

The invention relates to electrical engineering, in particular, to devices for back-up protection of transmission lines with branches to transformer substations.

A device for protecting transmission lines with bogging transformers is known, comprising current and voltage transformers, a filter start-up unit, a manipulation unit and a phase comparison unit, a viewer, a frequency transceiver, a shutdown unit.

The closest to the described by the technical essence and the achieved result is a device for protection of the transmission line with tapping transformers, containing current and voltage transformers, a filter current protection unit and a disconnecting unit.

The aim of the invention is to increase the sensitivity with symmetrical short-circuiting transitions from two-phase ones.

The goal is achieved by the fact that the device for backup protection of the line with tapping transformers contains current and voltage transformers connected to a current filter protection unit, the output of which is connected to the disconnecting unit consisting of a time relay whose winding is connected to the output contacts of the unit protection, and the first timed out contacts with time relays are included in the circuit breaker tripping circuit, phase-sensitive release units are added respectively active and reactive oh current line components, two delay blocks, two comparison blocks, maximum and minimum relays, with the inputs of phase-sensitive blocks connected to current and voltage transformers, the output of the phase-sensitive block of reactive current component connecting to the input of the first comparison block directly and through the first block delay, the code of the phase-sensitive active component component of the current is connected to the inputs of the second comparison unit directly and through the second delay unit, the outputs of the first and second blocks Comparison terminals are connected respectively to the maximum and minimum relays, whose outputs are connected to the disconnecting unit, and in the disconnecting unit in parallel the first time relay contact with a time delay is connected to a chain of successively connected second time relay with a minimum time relay contact, the closing contacts of the maximum relay, while parallel to the contacts of the protection unit, included in the time relay winding circuit, are connected the closing vderzhki time without contacts time relay and time relay winding shunted by a chain of successively sredinennyh third zamykayuschihs delayed time relay and razmykayuschihs output contacts of the relay.

FIG. 1 shows a block diagram of the device; in fig. 2 is a circuit block diagram in principle.

The device is connected to current transformers 1, installed on the protected line 2 with a power transformer 3 on the branch, and voltage transformer 4. The phase-sensitive block 5 of the reactive component of the current line 2 is connected to the phase A of the current circuits and the sun voltage circuits, the phase-sensitive block 6 of the active component of the current line 2 is connected to the phase A of the current and the AO voltage. A delay-capacitance block 7 is connected to the output of the block 5 which, together with the output of block 5, is connected to the input of block 8 of comparison with the maximum relay 9 connected to it. The output of block 6 is connected to an active capacitance block 10 of delay, the output of which, together with the output of block 6, is connected to the input of block 11 of comparison, with mini connected to it Relay 12.

The current filter protection unit 13 connected to the current and voltage transformers is connected to the shutdown unit 14, the output of which acts to turn off the switch 15.

The shutdown unit 14 contains (cMi, phi1, 2) time relays 16, the winding of which through the resistor 17 is controlled by the output, contacts 18 of the protection unit 13, is bridged by time 19 contacts of the time relay contacts 16,

The first timed out contacts 20 of the time relays are connected to the tripping circuit,

Parallel to contacts 20 there is a chain of successively connected second, short-circuiting, time-slipping contacts 21 of time relay 16, disconnecting contacts 22 of minimal relay 12 and closing contacts 23 of maximum relay 9. Time windings of relay 16 are bridged by a chain of third-connected third short circuits the time delay of the slipping contacts 24 and the opening contacts 25 of the protection unit 13. The phase-sensitive unit 5 supplies power from the transformer 4 and the transformer 1 to the current of the line 2 according to the nine-degree scheme, which reveals the reactive component of the current relative to the reference voltage when using, for example, an annular phase-sensitive scheme. The voltage from the output of the annular phase-sensitive circuit of block 5 is proportional to the reactive component of the line 2 current and is fed to the comparison block 8 directly and through the active-capacitive block 7 of the transmission delay of the magnitude of this component. Block 7 is an active-capacitive circuit with a constant time, longer than the time of operation of contacts 20 of relay 16 of block 13. The voltage of the capacitor of block 7 changes with a delay, which by the moment of actuation of the relay 16 from block 13 of protection to turn off the circuit breaker 15 2, the value corresponding to the mode before the occurrence of a short-circuit on the transformer 3, therefore, after block 8 comparing the voltage of the current moment and the moment to 1Y, the relay 9 receives a voltage proportional to the increment of the reactive component of the line 2 current. If the capacitor 7 charge resistance of the block 7, its discharge circuit with a similar delay both reduces the voltage on the capacitor while reducing the reactive component of line 2. The phase-sensitive block 6 switches on the current and voltage phases, which is similar to the principle of the power circuit Relay 12 through block 11 and block 10 provides control of the change in the active component of the current of line 2. 826 Since the resistance of transformer 3 is mainly reactive in nature, to detect the increment of current in line 2 by tive component of short-circuit current behind transformer 3, relay 9 is built to operate from reactive current, and relay 12 - to fall off, in the absence of an active component, a change in current of line 2. To unambiguously detect an increment of the reactive component of current in line 2 proportional to the additional short-circuit current behind transformer 3, relay 9 triggers only at a positive value of the current difference of the current moment and the preceding mode with the choice of the setpoint component of this current taking into account the possible operating modes of the line 2. Device works as follows. In case of a short circuit behind the transformer 3 of the branch line 2, the protection unit 13 trips, contacts 18 of which close the relay coil circuit 16. If the short circuit is asymmetrical, the contacts of protection 18 remain closed until the relay 20 contacts the maximum disconnecting switch of line 2.. If the short circuit changes from asymmetrical to symmetric, the three-phase protection contacts 18 of the unit 13 are opened, however, the relay 16 is self-holding at the contacts 19. I The first-time contact slipping off the contact You 21, whose setting is longer than the protection time of the transformer 2, prepare the tripping circuit only if there is an increment of the reactive component of the current in the line, which is determined by the closure of the contacts 23 of the relay 9 and the absence of an increment of the active component of the line current, which is determined by the closed state contacts 22 of the relay 12. If the short circuit was liquidated by the action of protection of the surge transformer 3, the circuit from the series-connected contacts 21–23 will be broken and the slip will be broken; , pins 24, setpoint for more than the first, zashun 71134082 8

time of winding. relay 16 time and the proposed device can ensure the readiness of the circuit to repeat. It is widely used for protection of spraying, lines with branches

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Claims (1)

DEVICE FOR RESERVE PROTECTION OF A LINE WITH STRAIN TRANSFORMERS, containing current and voltage transformers connected to a current filter protection unit, the output of which is connected to a trip unit, consisting of a time relay, the winding of which is connected to the output contacts of the zitsita block, and the first are closed with a second time time relays are included in the circuit breaker circuit, characterized in that, in order to increase the sensitivity to three-phase short circuits passing from two-phase ones, phase-sensitive blocks for separating the active and reactive components of the line current, two delay blocks, two comparison blocks, the maximum and minimum relays are connected, the inputs of the phase-sensitive blocks connected to current and voltage transformers, the output of the phase-sensitive block for separating the reactive current component connected to the inputs of the first block comparison directly and through the first delay unit, the output of the phase-sensitive unit for separating the active component of the current is connected to the inputs of the second comparison unit directly through the second delay unit, the outputs of the first and second comparison units are connected respectively to the maximum and minimum relays, the outputs of which are connected to the trip unit, and in the trip unit, in parallel with the first time-closing contacts of the time relay, a chain of series-connected second closing contacts with a delay is connected the time of the contacts of the time relay, the opening contacts of the minimum relay and the closing contacts of the maximum relay, while parallel to the contacts of the unit Protecting included in the time relay coil circuit connected closes without delay contacts time relay and time relay winding shunted by a chain of series-connected third ': Breaking time-delay relay contacts vre. change and expanding output contacts of the protection unit.