SU1628130A1 - Automatic device for compensating current and voltage losses due to single-phase ground - Google Patents

Description

I

(21) 4339689/07

(22) 10/01/87

(46) 02.15.91. Bul N 6

(71) Siberian State Institute for Designing Metallurgical Plants

(72) I.F.Antonov, O.V.Ulzituev, L.L.Genael and P.T. Yunnikov

(53) 621.316.761.2 (088.8)

(56) USSR author's certificate

No. 559325, cl. H 02 H 9/08, 1977.

(54) DEVICE FOR AUTOMATIC CURRENT AND CURRENT SINGLE-PHASE GROUND VOLTAGE

(57) The invention relates to electrical engineering, in particular to automatic devices for earth fault current compensation, and is intended for use in high-voltage cable networks of industrial enterprises. The purpose of the invention is to simplify by unifying the use of

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ore This is achieved by using a three-core magnetic core transformer as a compensating transformer 2. In order to expand the functionality in networks with large earth fault currents, an arcing reactor 3 is used in the device. In order to increase reliability, the device is equipped with a measurement and protection unit 6, and the purpose is to reduce the resistance

The invention relates to electrical engineering, in particular to automatic devices for compensating the earth fault current, and is intended for use in high-voltage cable networks of industrial enterprises.

The purpose of the invention is to simplify by unifying the use of equipment.

The drawing shows a diagram of the proposed device.

The device for automatic compensation of current and voltage of a single-phase ground fault consists of an adapter transformer 1, a compensating transformer 2, an arcing reactor 3, a voltage transformer 4, an automatic compensation control unit 5, a measuring unit and protection 6, and a switching unit 7,

A connecting transformer 1 which is connected to the network 8, has a primary winding 9 and two secondary windings 10, 11 and is manufactured by partially upgrading a downstream transformer of the required power, commercially available by the electro-industry. The primary winding of 9 g of connecting transformer 1, connected in a star, is connected to

network 8.

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The neutral of the primary winding 9 is connected to earth through a parallel-connected arcing reactor 3 and the primary windings 12, 13 of the compensating transformer 2.

The secondary winding 10 of the connecting transformer 1 is connected by a triangle to reduce the zero-sequence resistance, the secondary winding 11 is connected to

In the zero sequence, the connecting transformer 1 is provided with a second secondary winding 10 connected by a delta. The proposed device is switched on both automatically in a single-phase short circuit to earth and by personnel by acting on the automatic compensation control unit. 3 hp f-ly, 1 ill.

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The secondary windings 14, 15 of the compensating transformer 2 are connected to the star and to its neutral. The single-phase compensating transformer 2 is manufactured by partially upgrading a downstream transformer produced by the electroindustrial industry, in which the windings 12, 13 and 14, 15 located on the outermost cores of the magnetic circuit are connected according to a back-to-back connection scheme, to avoid voltage being applied to the windings 16, 17 located on the middle core of the magnetic circuit, which are disconnected from the output terminals, first The winding 18 of the voltage transformer 4 is connected to the network 8, to the first secondary winding 19 of the voltage transformer 4 connected according to the star with the derived neutral, and another secondary winding 20 connected according to the open triangle is connected to the automatic compensation control unit 5, the output of which is connected to the switching unit, the measuring and protection unit is switched on in the secondary windings 13 of the compensating transformer 2.

The transformation ratios of the connecting transformer 1 and the compensating transformer 2 are assumed to be the same, and the power of each of the secondary windings 10, 11 of the connecting transformer 1 is 50% of the rated power of the primary winding 9.

In the case of single-phase short circuit to earth (for example, phase A), the equality of the three-phase system voltage and the signals from the secondary

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Transformer coil 14, 20, voltage HHVI A, is fed to automatic compensation control unit 5, which determines the critical phase, and switches on switching unit 7, thus supplying the necessary secondary voltage from winding 11 of connecting transformer 1 to windings 12, 15 of the compensating transfer transformer 2. Since the transformation ratios of the compensating transformer 2 and the connecting transformer 1 are the same, the voltage transformed in the windings 12, 13 of the compensating transformer 2 is equal to an off voltage network 8 and the network is applied between the neutral point and ground. Due to this, the voltage (potential) of the damaged phase relative to the earth becomes very small. If the earth fault is cleared (the grounding arc has gone out), then only the mains source is disconnected from the neutral, and the potential compensation source is maintained through the compensating transformer, therefore the voltage of the damaged phase relative to the earth is kept at a low level at which arc re-ignitions are avoided. In this mode, the device operates until the time expires, which is preset on the delay element of the automatic compensation control unit 5, after which the switching unit 7 turns off c and the potential compensation voltage is removed from the network neutral. If the network isolation has been restored, the switching unit 7 is no longer turned on, and the automatic compensation control unit 5 is placed in a state of waiting for a new ground fault. If the earth fault has not been cleared, the automatic compensation control unit 5 re-automatically switches the switching unit on after a time delay and the compensating voltage is switched on again between the neutral of the network and the ground and the cycles are repeated until the insulation of the network is restored.

If during the operation of the automatic compensation device in the electrical network 8 there is a short circuit to earth of another phase, then a current flows in the compensation circuit, exceeding the setting of the response of the measurement and protection unit 6, and at the same time

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thematic compensation control 5 and the switching unit 7, the compensating transformer 2 is disconnected from the winding 11 and the voltage from the neutral winding 9 is removed.

Claims (3)

1. Device for automatic compensation of current and voltage of a single-phase earth-fault, containing a connecting transformer, and its source is connected to the star and neutralized is the secondary winding of the compensating transformer. , and a voltage transformer connected to the leads for connection to the network, to the outputs of which the fixing unit is connected to the ground and select the damaged phase, the output of which is connected to the i. -hil switch on (.About the head - it is obvious: see that, for the purpose of yni-seni by unifying the use of equipment, the transformer with a three-rod magnetic conductor, the primary windings of which, located on the extreme cores of the magnetic circuit, are connected in parallel and included in the the neutral of the primary winding of the connecting transformer, the secondary windings of the compensating transformer located on the extreme cores of the magnetic circuit are connected in parallel opposite and connected to one output ohm to the neutral of the secondary winding of the connecting transformer connected in a star, and the other output - to the switching unit. 1 16281308 2. W (according to clause I, of the measures and protection included in 1 h in s with so that, for the purpose of one of the conclusions of the secondary expansion of the functional possibilities of the compensating transformer-n networks with large currents for-5 Pa and the switching-off input of the commutation unit to earth, arc-tation. extinguishing reactor included in the primary neutral winds of the attachment-4. A device according to claim 1, about a tl of a transformer between which, in order to dami the primary winding, compensate-JQ for reducing the resistance of the zero primary transformer, 3. The device according to claim 1, of which the transformer is equipped with a second secondary PI PI with the fact that. With the purpose of a winding connected by a triangular reliability, it is equipped with a block.