SU1653058A1 - Functional power supply for substation with precharged capacitors - Google Patents

Abstract

This invention relates to electrical engineering, in particular, to relay protection of electrical installations. The purpose of the invention is to expand the field of application of the charge and power device in the case of a series connection of groups of built-in current transformers. The goal is achieved by the current charge unit 8 being connected in series to the current circuits of the relay protection unit 7, the opening contacts 9 and 10 of which bypass the input of the unit 8 in short circuit modes. 3 il.

Description

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The invention relates to electrical engineering and is intended to create an operational power supply at substations by charging capacitors from a current charge unit.

The purpose of the invention is to expand the field of application of the charge and power device in the case of a series connection of groups of embedded current transformers.

Figure 1 shows the primary substation diagram; Fig. 2 is a circuit for switching on a current charge unit; FIG. 3 is a circuit for charging capacitors,

The primary circuit consists of a power transformer 1, a separator 2, a short-circuit 3, a switch on the low side 4 and measuring current transformers 5 connected on the high side,

The switching circuit of the current charge unit contains a group of current transformers 6 connected in pairs in each phase, a relay protection unit 7 and a current charging unit 8 shunted by disconnecting contacts 9 and 10 of the relay protection unit 7.

A circuit for charging capacitors is formed by a voltage charging unit 12 connected to the secondary winding of a transformer 11, a charging unit 8 for current, a connecting resistor 13, capacitors 14 and 15 with separation diodes and an output relay-repeater activated by disconnecting contacts the relay protection unit 19-21 through the threshold element 22 and the winding of the turn-on electromagnet 23, which is connected to the capacitor 15 by the contact 24 of the repeater 18. The threshold element 22 of the relay action can be implemented on Ore or a thyristor with a zener diode in a control circuit.

The device works as follows.

If the damage in the primary circuit of the substation occurs during the operation of the power transformer 1, then the capacitors 14 and 15 are charged from the charging unit 12 by the voltage and ensure that the short circuit 3 is turned on (winding 23). If the power transformer 1 is turned on for a short circuit when the capacitors 14 and 15 are uncharged, and after the power transformer 1 is turned on, the voltage at the input of the charging unit 12 is insufficient for charging the capacitors 14 and 15 to a value sufficient to operate the drive windings of the electromagnet of switching on the short-circuit 23, then until the relay protection unit 7 trips, the current charge unit 8 is shunted by disconnecting contacts 9 and 10 and does not load the current transformer5.

After the relay protection unit 7 (output relays) trips, the current charging unit 8 is de-charged and the capacitors 14 and 15 are charged from the unit

8 charge current.

The threshold element 22 is designed to prevent the capacitor 14 from being discharged onto the winding of the output repeater 18 until it is fully charged (to provide

reliable relay operation). After charging the capacitors 14 and 15, the output repeater relay 18 is triggered, then the electromagnet 23 turns on the short circuit 3.

Thus, the proposed device allows to expand the area of application of the charging and powering device in the absence of special current transformers at simplified substations.

switching on the current block in the relay protection circuit and applying the principle of de-shunting this block in short-circuit modes.

Claims (1)

Invention Formula A device for operational power supply at substations with precharged capacitors, containing a group of current transformers, to the secondary windings of which a relay protection unit is connected, a current charging unit, a voltage transformer, to which a secondary charging unit is by that in order to expand the field of application of the charge and power devices in case of series connection of the built-in current transformers, the current charge unit is connected in series with current circuits power supply of the relay protection unit, the opening contacts of which shunt the input of the current charging unit. 1