SU879517A1 - Device for checking high voltage three phase electric machine insulation - Google Patents

Description

The invention relates to an emergency control system and is intended for use in high-voltage electrical networks with water when disconnected. It is also known to provide a protective disconnection of a three-phase electrical installation containing a switch, a switch contact terminal connected through a measuring unit to a high-voltage rectifier unit, a source of operating current and actuator l. In this device, the measuring unit immediately connects the auxiliary contact to the power circuit when the switch is disconnected, which is completely unacceptable for high-voltage networks, when the voltage in them after the switch is disconnected relatively slowly decreases due to charging of powerful synchronous motors, condensers, etc. The aim of the invention is to improve the reliability of high-voltage three-phase electrical installations. The goal is achieved by the fact that a switch, a switch contact connected through a measuring unit to a high voltage rectifier unit, a source of operating current and an executive element connected to the measuring unit, a delay element and a high-voltage single-pole switch unit are inserted into the device for controlling the isolation of a high-voltage three-phase electrical installation. , with the corresponding inputs of the delay element connected to the first and second inputs of the measuring unit, and the output of the delay element connected to the control input of the high-voltage single-pole breaker unit, the first inlet of which is connected to the output of the operating current source and the third output of the measuring unit, and the second output of the high-voltage single-pole breaker unit is connected to the output of the high-voltage rectifier block. The drawing shows a block diagram of the proposed device. The device contains a switch 1, an actuating element 2, a block 3 of a high-voltage rectifier, a block 4 of a high-voltage single-pole switch, a measuring block 5, a delay element 6, a source 7 of a control current, a block-contact 8.

The device works as follows.

In the initial state, the contacts of the switch 1 are closed, the controlled line is under voltage, the block ™ contact 8 of the switch 1 is open. Unit 5 is de-energized and disconnected from the monitored line. When the line is disconnected by the switch 1, its blocking contact .8 closes, the voltage is applied to. .block 5 and element b. After a period of time due to the element 6, the switch 4 is closed, and the block 5 is connected via a block 3 of the high-voltage rectifier to a de-energized line, the resistance of which is monitored. Unit 3 high-voltage rectifier, skip operational (measuring) current, almost isolates the phases from one another. If the insulation resistance is satisfactory, element 2 switches on switch 1. If the insulation resistance is below the set level, block 5 outputs a signal to. blocking of element 2, and the inclusion of lini-nii does not occur.

The isolation control device prevents the connection of block 5 to the high-voltage line until it has eliminated high residual voltage.

This makes it possible to increase the reliability of operation of both the insulation control device itself and the monitored electrical network and makes it possible to use it to control the isolation of a high-voltage network with water when it is disconnected. The economic effect is achieved by increasing the duration

services to control the level of insulation and reduce the damage caused to consumers during interruptions in power supply.

Claims (1)

1. USSR author's certificate No. 371646, cl. H 02 h 7/00, 1971 (prototype).