SU1614063A1 - Device for charging capacitors from current transformers - Google Patents

Abstract

The invention relates to relay protection and is intended for charging storage capacitors that supply relay protection and automation systems for substations without a constant operating current. The purpose of the invention is to reduce the error of current transformers by reducing the internal resistance of the capacitor charge device while saturating the current transformer magnetic core. This goal is achieved by the fact that a third full-wave rectifier is additionally introduced into the device for charging capacitors from current transformers, which is connected to a partitioned secondary working winding of an intermediate current transformer. 1 il.

Description

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(21) 4370956 / 24-07 (22) 14.12.87 (46) 15.12.90. Bul N; 46

(71) Novocherkassk Polytechnic Institute. Sergo Ordzhonikidze

(72) N.I. Tsygulev and V.G.Shul to (53) 621.316.925 (088.8)

(56) USSR Copyright Certificate No. 736247, cl. H 02 H 3/28, 1970.

USSR Author's Certificate Ns 1317536, cl. H 02 H 3/08, 1987 (54) DEVICE FOR CHARGING CONDEN SATORS FROM CURRENT TRANSFORMERS

(57) The invention relates to relay protection and is intended for charging accumulative

capacitors supplying relay protection and automation networks of substations without a constant operating current. The purpose of the invention is to reduce the error of current transformers by reducing the internal resistance of the capacitor charge device while saturating the current transformer magnetic core. This goal is achieved by adding a third full-wave rectifier to the device for charging capacitors from current transformers, which is connected to a partitioned secondary operating winding of an intermediate current transformer. 1 il.

The invention relates to electric power industry and is intended for charging the storage capacitors of relay protection of substations without a constant operating current.

The purpose of the invention is to reduce the error of the current transformer by reducing the internal resistance of the capacitor charge device when the current transformer magnetic field is saturated.

The drawing shows a diagram of the proposed device.

A device connected to current transformer-1 contains an intermediate transformer 2 with primary 3, working 4 and control B windings, a two half-time rectifier 6 with a key thyristor 7 in the diagonal, a second two-half-rectifier 8, a zener diode 9, three-phase full-wave high voltage 10, shunt thyristor 11

with a zener diode 12 in the control circuit, a separation diode 13 and a storage capacitor 14.

In the absence of a charge on the storage capacitor 14, the key Thyristor 7 is closed, therefore, only the upper half of the operating winding 4 is connected to the rectifier 10,

The device works as follows.

When current appears in the secondary winding of the current transformer 1, the charge of the storage capacitor 14 starts across the upper half winding of the working winding 4 through the rectifier 10. The voltage on the capacitor 14 increases in proportion to the current transformer 1, causing the voltage on the working winding to increase 4. Since the control winding 5 is magnetically coupled to the working winding 4, then. the voltage on it grows at the same rate. When you reach the manager about h

ABOUT

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The voltage 5 of the breakdown of the Zener diode 9 n | oojedo opens the opening of the key thyristor 7. The current in the middle tap of the working winding 4 becomes equal to zero and the further operation of the storage capacitor 14 is carried out using the entire working winding 4 through the key thyriser 7 and the extreme branches of the rectifier 10. In this case, the reduction of the internal resistance is proportional to the change in the cradle of the transformation ratio of the intermediate transformer 2. As a result, the charge current decreases.

I When the voltage on the storage capacitor 14 reaches a predetermined level, the opening of the shunt thyristor 11 occurs, which maintains the predetermined level on the storage capacitor 14. This is ensured by closing the thyristor when the tank goes through the zero value and turns it off. on it is given a voltage level.

Claims (1)

Claims An apparatus for charging capacitors from current transformers comprising an intermediate current transformer, the primary winding of which is intended to Connections to the output terminals of the current transformer, to the output terminals the operating winding of the intermediate current transformer is connected to the first full-wave rectifier, to the output of which is connected a shunt thyristor, the cathode of which is intended to be connected to the first plate of the storage capacitor, the control electrode is connected through the first zener diode to its anode for connection to the second plate of the storage capacitor, a second two-pole is connected to the output terminals of the control winding of the intermediate current transformer An upstream rectifier, to the first output of which the cathode of the second Zener diode is connected, is a key thyristor, which, in order to reduce the error of the current transformer by reducing the internal resistance of the charge device of the capacitors during saturation of the current transformer magnetic conductor, the third full-wave rectifier, with the first input of the first full-wave rectifier connected to the beginning of the working winding, the second input to its midpoint, the third input to the end of the working winding The coils are through a third full-wave rectifier, the diagonal of which includes a key thyristor, the control electrode of which is connected to the anode of the second zener diode, and the cathode to the second output of the second full-wave rectifier. Z /four