RU1818654C - Method for detection of line with deficient resistance of insulation - Google Patents

Abstract

Usage: can be used to identify lines with reduced insulation resistance to ground. SUMMARY OF THE INVENTION: the device comprises a measuring shunt included in the dissection of one phase of each outgoing line from the busbar section of the substation, a galvanometer connected to the shunt, and a device for continuously monitoring the insulation resistance, which allows to increase the current of the measuring circuit for the duration of the determination of the line with reduced insulation resistance tion. 1 ill.

Description

The invention relates to the field of electric power (power supply to industrial enterprises) and is intended to determine a line with a reduced insulation resistance relative to the earth when it is hundreds of kilo-ohms and below and is intended for networks with insulated neutral.

The aim of the invention is to increase the reliability and safety of electrical installations.

The goal is achieved in that a measuring shunt is installed in one of the phases of each outgoing line and a galvanometer is connected to the shunt with a current division value of at least A / division. In networks of 6-10 kV, the galvanometer should be high voltage (can be used conventional galvanometer installed on

self-powered insulating base and meeting the requirements).

A device for continuous monitoring of the insulation resistance is connected to the network, which makes it possible to increase the current of the measuring circuit during the detection of a line with a reduced insulation resistance.

In addition, the voltage of the measuring voltage source of the device should be not less than about 1000 V.

The drawing shows a schematic diagram of a device.

The device includes busbar sections 1 of the substation, outgoing lines 2, 3 from the bus section (two lines shown), measuring shunts 4, which are installed in the cells of each outgoing line of the busbar section of the substations, special galvanic00

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meters 5, connected to each measuring shunt, a device b for continuous monitoring of insulation resistance, which includes a voltage switch 7, diode 8, resistor 9, single-phase transformer 10, in the secondary winding of which is included a device 11 for visual monitoring of insulation resistance against earth .

The connections and relative positions of the elements of the device are as follows. An additional winding 12 of the rod transformer through the voltage regulator 15 is supplied with a reduced voltage and an EMF is induced on the primary winding 13 and a voltage is created that coincides in phase in three phases, through which diode 8, resistor 9, the primary winding a single-phase transformer 10 flows a rectified current la, in the event of a decrease in the insulation resistance at one of the outgoing lines (e.g., at point 16 of line 3), as shown in the drawing. This current then flows through the measuring shunt of the line, on which the insulation resistance decreases (in this case, on line 3), and to the winding 13 of the rod transformer. By deflecting the arrows of the galvanometer 5 (in this case, line 3), it is possible to determine a line with a reduced active insulation resistance relative to the ground. The galvanometer shows a constant component of the rectified current Is. Since the current Is is rectified, due to the periodic components in the secondary winding of the transformer 10, an EMF is induced and the device 11 visually shows a general decrease in the insulation resistance with a signal, and a galvanometer refines the line with a reduced insulation resistance. In order to indicate the galvanometer more and more efficiently, it is possible to determine a line with a low active insulation resistance, a switch 7 is provided, with which the voltage on the windings 12 and 13 increases, and the current increases, while searching for a line with a low insulation resistance la and its constant component, fixed by a galvanometer.

The device 6 is located in the independent cell (chamber) of the substation.

The device operates as follows. When the insulation resistance decreases relative to the ground on the outgoing line 3, for example, at point 16 (a piezistor connected between the float and the ground is shown), CONSTANT CONSTANT.

The rectified current from the device for continuous monitoring of the insulation resistance flows (shown by dashes) mainly through the place where the insulation resistance decreases (at point 16) of line 3. At point 16, the current branches out both through the measuring shunt 4 of line 3 and through the windings a receiver of electrical energy supplied from line 3 and further to a device for continuously monitoring the insulation resistance. Since the constant component of the rectified current flows from the device through the measuring shunt 4 of line 3, the galvanometer needle deviates from the zero position and it determines the line on which the insulation resistance decreased. Based on the reading of this galvanometer, it is possible to determine a line with a reduced active resistance of isolation if a decrease in isolation occurred at other phases of the indicated line.

To make the galvanometer read more and more efficiently, you can define

pour resistance line

isolation, it is necessary at the time of determining the line with a low insulation resistance switch 7. increase the voltage at the terminals of the open triangle of the device, respectively, increase the current Is and the DC component of the current that flows through the galvanometer line with a low insulation resistance

5 relative to the earth.

The fact that the insulation resistance has decreased on the discharge lines will signal the device for continuous monitoring of the insulation resistance, and specifically on which

0 lines, galvanometer will show.

Claims (1)

SUMMARY OF THE INVENTION A device for detecting a line with a low insulation resistance, comprising an NTMI voltage transformer of type 5, characterized in that, in order to increase the reliability and safety of electrical installations, measuring shunts are introduced, included in the cut-out of one phase, each departing from 0 substations of the line and a special galvanometer is connected to each shunt, the primary windings of the voltage transformer connected in the star circuit are connected to the busbar section of the substation, in 5 neutral of which a diode, a resistor, and a primary winding of a single-phase transformer are connected in series, the secondary winding of which is connected to a visual insulation kitrol device of insulation resistance OTNOOIT LKMS .1Ј ... i-pyni 4 the secondary three-phase windings of the voltage transformer is connected in a star circuit, the second group of secondary three-phase windings of the voltage transformer is connected in an open triangle circuit, in series with which a switch is connected, the fixed contact of which is connected to the common point of a single-phase autotransformer, and the switched contact to one of the solders of this autotransformer, the common autotransformer winding is connected between the phases of the secondary group of three-phase windings connected according to the star circuit.