SU1334249A1 - Device for maximum current protection on sectionalized switches of substantions and mains - Google Patents

Abstract

The invention relates to electrical engineering and can be used for overcurrent protection at an alternating operational current at a standard), but open sectionalizing switches of the substation and networks. The purpose of the invention is to increase reliability by providing a time independent of current. The goal is achieved by introducing into the device of the crushing contacts of the relay 8 time with a delay for return. In this case, the time delay for the return is created by removing the voltage from the winding of the relay 8 time with a return delay by the contact of the switch 10 and the opening auxiliary contact 11 of the switch position. 1 il. with (L

Description

113

The invention relates to electrical engineering and can be used for overcurrent protection at an alternating operational current at normally open sectionalizing switches of substations and networks.

The purpose of the invention is to increase reliability by providing time-independent time.

Figure 1 shows a schematic diagram of a device for overcurrent protection on an alternating operational current on a normally open sectional switch with two intermediate relay-disconnecting relays, for example Pn-341i in figure 2 - current circuits in FIG. AC current types EV-215-EV-245

Device for maximum current

(The protection howl contains a sectioning switch 1 with a breaker auxiliary contact of the switch position and an AC drive, current transformers 2, to which direct current instantaneous relays, such as RTM, are used as electromagnets for 3 disconnections and connected according to a de-shunt circuit, and the primary windings of 4 current current transformers, the secondary winding 5 of each of which feeds the winding of the intermediate deshuntiing relays 6 with switching without opening the circuit by contact, Example through vtr mitel- ny bridge 7,

Relaying relays. 6 controlled

Relay 8 time delayed return. performed with two time delays, with the smaller of them acting on the triggering of the intermediate de-shunt relays 6, and most of the time removing protection from operation by shunting the secondary windings 5 of saturating transformers. The time-independent time delay is achieved by using tripped electromagnets 3 off and Relay 8 time delayed return with an independent g from the current response time, for example, electromechanical time relays with a clock mechanism of the EV and PB series, under Luciano to control shred, wherein the time delay when the return is generated by deprotection voltage relay coil 8 with a delay time on the return contact of the switch control circuit 10 and the NC contact 11 of the switch position 1.

The device works as follows.

If there are malfunctions in the operational circuits and voltage loss on the control slots (CW) of the time relay 8 with a delay for return and the turn-on electromagnet 9, they lose power, but unnecessary operation or failure of the automatically introduced protection during a short circuit in its area of operation is excluded since it is impossible to carry out the operation of switching on the switch 1 because of the open switching circuit. In the on and off positions of the switch 1 circuit of the electromagnet 9

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the time relay contacts 8 with the start-up Q and the winding relay .8 time-to-return, providing an automatic return delay is also open

tic input and output, as well as a current-independent characteristic of the protection time delay, the winding of which connects to the voltage transformer or to the own transformer via the control busbar (SC) parallel to the electromagnet 9 turn on.

The contact of the switch 10 of the control circuit, for example, three positions with the switching mechanism latching in the neutral position (with self-return) is connected in series with the break contact 11 of the position of the switch 1 and with the windings of the turn-on electromagnet 9 and the time delay 8 with the return delay connected in parallel.

0

Relay 8 time delayed return. performed with two time delays, with the smaller of them acting on the triggering of the intermediate de-shunt relays 6, and most of the time removing protection from operation by shunting the secondary windings 5 of saturating transformers. The time-independent time delay is achieved by using tripped electromagnets 3 off and Relay 8 time delayed return with an independent g from the current response time, for example, electromechanical time relays with a clock mechanism of the EV and PB series, under Luciano to control shred, wherein the time delay when the return is generated by deprotection voltage relay coil 8 with a delay time on the return contact of the switch control circuit 10 and the NC contact 11 of the switch position 1.

The device works as follows.

If there are malfunctions in the operational circuits and voltage loss on the control slots (CW) of the time relay 8 with a delay for return and the switching electromagnet 9, they lose power, but an excessive response or failure of the automatically introduced protection during a short circuit in its area of operation is excluded since it is impossible to carry out the operation of switching on the switch 1 because of the open switching circuit. In the on and off positions of the switch 1 circuit of the electromagnet 9

five

five

five

ABOUT

five

And the device for overcurrent protection is out of action,

In the on and off positions of the switch 1, the circuit of the electromagnet 9 is turned on and the winding of the relay 8 time with a return delay is open. This automatically removes the overcurrent protection device in the end positions of the switch 1, since the secondary circuits 5 are connected; the transformers are bridged by the time relay contacts 8 (Fig 2), and the electromagnets 3 are disconnected by the contacts of the intermediate de-shunt relays 6 (Fig. ).

When giving the command to turn on the switch 1 (Fig. 2), the start of the relay 8 of time with a delay for return occurs before and independently of the operation of the electromagnet 3 tripping. Relay 8 time delayed return is triggered instantly. The turn-on circuit is closed for a short time until the turn-on operation is completed. During this time, the time delayed relay 8 is timed to operate, since the on-time of the on switch 1 is longer than the time delayed by the return delay of the relay 8.

For example, the intrinsic switch-on time of a switch of the ВМПП-10 type with a drive should be no more than 0.2 g, and the response time of the EV-235 time switch when the voltage is applied is 0.02 s (according to experimental data), which ensures reliable operation of the circuit .

The opening contact 11 of the position of the switch 1 is opened at the end of the stroke of the switch and the after-voltage of the relay 8 time delayed to return returns with a delay time.

. The return of the relay of the relay 8 time delayed return does not depend on the state of the electromagnets 3 disconnect

This creates specific conditions for the operation of automatically introduced overcurrent protection in the event of a short circuit.

In normal operation, after switching on switch 1, time 8 relay with a return delay with less time latch closes the circuit of intermediate relay relays 6 and load current less than the overcurrent protection current setting, switch 1 does not turn off.

With a longer time delay, the relay 8 times with a return delay automatically deactivates the protection.

In emergency mode, after switching on the switch 1, a short time relay 8 with a delayed return delay with a shorter time delay closes the winding circuit of the intermediate relay 6 relays and with an increase in short circuit current above the overcurrent protection setting, the intermediate relay shunt relays 6, which electromagnet 3 trips are shunted, secondary short-circuit currents pass through them and they operate.

When used for starting intermediate de-shunt relays 6 impulses34249

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4 relays 8

Relay contacts and time delayed return the circuit of the winding of the intermediate relay 6 is open in the end positions of the switch 1 and therefore no shunting of the secondary winding 5 of the current transformers is required.

Thus, the proposed overcurrent protection at an alternating operational current at the sectioning switches selectively functions at phase-to-phase short-circuits and allows to increase the reliability of operation.

Claims (1)

Invention Formula is 20 thirty 40 45 35 A device for overcurrent protection at sectionalizing switches of substations and networks; containing a current transformer, the primary windings of which are included in the corresponding phases of the sectioning switches, the beginnings of the windings of the corresponding opening electromagnets are connected to the beginnings of their secondary windings, the beginnings and the ends of the windings of each of the opening electromagnets are connected to the respective fixed contacts of the corresponding intermediate disconnecting relays, to the terminals of the movable switching The contacts of each of the intermediate de-shunt relays are connected to the beginning of the primary windings. The fast current transformers, the ends of said windings are interconnected and connected to the ends of the secondary windings of current transformers, to the secondary winding of each of the fast converting current transformers connected through a rectifying bridge, the winding of the corresponding intermediate deshuntirovanie relay, parallel to the input of each rectifier bridge is disconnected time relay contact with return time delay, winding is The CQ time relay is connected in parallel to the winding of the turn-on electromagnet, which is connected to the control busbars via a series-connected break contact of the switch position and through the contact of the control circuit switch, characterized in that it ensures reliability from the current current time 55 51334249 In this case, it is additionally equipped with a series of which are connected in series with contacts with time lag with the winding of the corresponding process and the return of the time relay, each of the exact deshunter relay. fig 1 Fib.Z Re cactor I. Bandura Compiled by K.Shipan Tehred M.Dndyk Order 3972/51 Circulation 617 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Mosyva, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, ul, Proektna, 4 Proofreader A.T. sko