SU421083A1 - DEVICE FOR SELECTIVE PROTECTION AGAINST GROUNDS ON THE GROUND IN THE WINDING OF THE STATOR GENERATOR - Google Patents

Description

one

The invention is based on devices for selective zash, ity from earth faults in the stator winding of generators working in ukruiennyh blocks with direct connection to generator generating voltage.

A device containing a reference current source connected in series with an arcing coil is known, a zero-sequence current filter which is connected through the brake unit to the input of the logic unit. This device is not reliable enough.

The proposed device is equipped with a start-up body, one of the inputs of which is connected to the secondary winding of the arcing coil, the other to the source of control current, and a selective authority, one of whose inputs is gender, connected to the same source, the other to the filter of current zero and succession, and the outputs of these bodies are included in the logical block. This embodiment of the device increases its reliability.

The drawing shows a schematic diagram of the device.

The device consists of a control current source 1 connected in series with the arc-suppressing coil 2 of the generator 3 of the filter 4 of the zero-sequence current, the start-up body 5, the electoral body 6, the braking unit 7 and the logic unit 8.

A control current with a frequency below industrial, for example 25 Hz, is superimposed on the nervous values of the generators, and the phase of the auxiliary frequency of the arc coil 2 and the comparison of the phase of the current of the same frequency on the outputs of the generator 3 are measured.

with the phase of source voltage of the control current.

The starting body 5 of the generator is connected to the secondary winding of the arcing coil 2 and to the measuring winding of the control current source 1. The electoral body is connected to a three-transformer filter 4 of zero-sequence currents installed on the generator 3 terminals and to the measuring winding of the source of the control current.

The brake unit 7 is connected to the filter 4 current zero-sequence. The outputs of the bodies 5, 6 and block 7 are connected to the logical block 8.

When new ground closures are imparted at one point of the stator of the generator 3 of the enlarged unit, start-up bodies 5 of all generators of the block are triggered by measuring the phase with a frequency of 25 Hz in the voltage of the measuring winding of the arc coil relative to the reference current source. At the same time, the electoral body of the generator on which the closure has been closed is triggered.

The election authority compares the phase of the current of the zero sequence with a frequency of 25 Hz

on the generator leads in relation to the on-voltage voltage.

The outputs of the starting and electoral authorities are connected to a logical block containing the scheme “I.

The logical block of the generator, in which the start and electoral bodies worked, is triggered. The braking unit provides protection for external phase-to-phase short-circuits and double circuits to the ground, but an increase in the unbalance current of the zero-sequence current filter.

Subject invention

A device for selective protection against earth faults in the generator stator winding, containing a control current source connected in series with an arcing coil, zero sequence current filter, which is connected through the brake unit to the input of a logic unit, characterized in that it is equipped with a starting body, one of the inputs of which is connected to the secondary winding of the arcing coil, the other to the source of the control current, and a selective authority, one of whose inputs is connected It is also to the same source, the second is to the zero-sequence current filter, and the outputs of these organs are connected to the logic unit.

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