RU2649090C1 - Device for determination a place with damaged insulation of installation in networks - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering and is aimed at finding locations of damage to the insulation of installation in networks. Device includes an audio frequency generator installed between the "ground" and the wire with a reduced insulation resistance, electrical clamps connected to the selective receiver. In this case, the audio frequency generator contains a frequency and phase current converter, has a physical communication line, and the selective receiver includes a signal receiver transmitted via a physical link, phase distortion compensator, comparator, direction indicators.

EFFECT: technical result consists in the ability to determine the direction of the site with damaged insulation of installation in networks with a branched installation scheme, with looped power systems and in case of non-zero (up to 100 kΩ) insulation resistance visually.

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Description

The invention relates to electrical engineering and is directed to the search for places of damage to insulation of installation in networks.

Known patent RU 2310211, publ. November 10, 2007, in which a method for searching for an element with a reduced insulation resistance in a branched electric network of direct operating current is disclosed. The essence of the known method: the control alternating current and high-frequency current pulses are superimposed on the network, synchronized with the moment of transition through zero of the alternating voltage at the poles of the network. The duration of the high-frequency current pulses is equal to half the period of the control alternating current. The control alternating current and high-frequency current pulses in the current of the element under control are isolated. The active component of the alternating current is measured based on the calculation of the half-periods of the high-frequency current falling into the time interval between the moment when the alternating control current of the controlled element passes through zero and the moment the high-frequency current pulse disappears. Determine the decrease in insulation resistance in the controlled element upon the increase in the active component of the current.

The known method is applicable with significant limitations:

1. It cannot be used with a large number (loads) of consumers connected in parallel;

2. Plus and minus batteries for alternating current is the same electrical unit, that is, for alternating current, plus and minus batteries have the same potential. In this case, it is impossible to determine even the name of the battery pole with a short circuit to ground, not to mention the case with reduced insulation resistance.

The main ways to find places of insulation damage in networks up to 1 kV with isolated neutral is to turn off the supply lines at the substations one by one and apply an increased frequency current to the network. In this way, it is impossible to find a damaged section if it is supplied by parallel lines or insulation deterioration has occurred in several places of the network in one phase. In addition, it takes a lot of time to search for damage and it is also not possible to find a damaged line with short-circuit to ground.

The method of applying an increased frequency current to the network was used in a device for finding insulation damage in networks with isolated neutral developed by Soyuzkhimpromenergo (see http://forca.ru/knigi/arhivy/ustroystva-elektrobezopasnosti-6.html), which we selected the closest analogue. In this device, the voltage from the sound generator 0.8-1.2 kHz is supplied to the network. The damaged line is searched for by special electrical measuring clamps, sensitive only to currents with a frequency of 1 kHz. They are made on the basis of Ts-30 type electrical ticks.

A disadvantage of the known technical solution is that in this way it is possible to solve the problem only in simple power supply systems, with the system powered on the one hand, with a small number of wires in the bundles and the absence of duplication. Connecting an audio frequency generator between the “ground” and the wire with a reduced insulation resistance, moving along the wiring harness of the wires using current clamps connected to a selective receiver, in the direction of decreasing the signal level, does not always allow finding the path of the current flowing to the place with the reduced insulation resistance. This solution does not allow you to find a place of reduced mounting resistance in a complex looped wiring diagram.

It is especially difficult to determine the direction of movement to the desired point by reducing the signal level with a branched mounting scheme, with looped power systems and in the case of non-zero (up to 100 kOhm) insulation resistance does not allow unambiguously (and because of the signal frequency induced on adjacent wires). This makes search very difficult, and sometimes makes it impossible.

The technical result of the claimed invention is that it is possible to determine the direction of a place with damaged installation insulation in networks with a branched installation scheme, with looped power systems and in the case of non-zero (up to 100 kOhm) insulation resistance visually.

The claimed technical result is achieved as follows.

A frequency generator is connected between the ground and a wire with damaged insulation (0-100 kOhm) on a wire going from the generator to the power pole, put on the electrical measuring clamps of a selective receiver tuned to the signal frequency, according to the readings of the light indicators, determine the presence of the signal frequency in the bundle, and the color of these indicators determines the direction of the search for a place with damaged insulation.

A device for implementing the method includes an audio frequency generator connected between the “ground” and the wire with a reduced insulation resistance, electrical clamps connected to a selective receiver. The audio frequency generator contains: a frequency and current phase converter, has a channel (two wires), and the selective receiver further includes a signal transmitted through a communication line, a phase distortion compensator, a comparison device, direction indicators for finding a place with damaged insulation.

A communication line is a physical pair, for example, two copper wires in insulation or a coaxial cable.

The invention is illustrated by illustration.

In FIG. 1 shows a block diagram of the inventive device, where:

1 - sound frequency generator;

2 - “earth”;

3 - wire with reduced insulation resistance;

4 - connecting wire;

5 - frequency and phase current converter;

6 - transmitter;

7 - physical communication line - a physical pair, for example, two copper wires in insulation or a coaxial cable;

8 - electrical measuring pincers;

9 - receiver;

10 - direction indicators;

11 - mounting harness;

12 - selective amplifier;

13 is a comparison device;

14 - phase distortion compensator.

The proposed device for finding places of damage to the insulation of the installation of networks allows you to determine the direction of the search not by reducing the signal level, but visually.

The device operates as follows: the sound frequency generator 1 is turned on between the “ground” 2 and the wire with damaged insulation (0-100 kOhm) 3. The sound frequency generator 1 contains a frequency converter and current phases 5, a transmitter 6, and an electrical clamp meter 8. Before starting the search places with damaged insulation on the connecting wire 4, going from the sound frequency generator 1 to the wire with damaged insulation 3, put on the measuring clamps 8 of the selective receiver 9, tuned to the signal frequency. At the same time, the direction indicator 10, one of two colored LEDs, for example, in the direction “from the generator”, lights up on the case of the electrical measuring tongs 8 or on the device case. The signal from the electrical clamp meter 8, worn on the mounting cable 11, enters the receiver 9 and is then fed through a selective amplifier 12 to the first input of the comparison device 13. The signal generated by the frequency and current phase 5 in the sound generator 1 and transmitted by the transmitter 6 through the physical communication line 7, which is a physical pair (two copper wires in isolation or a coaxial cable), and then received by the receiver 9 through the phase distortion compensator 14, is fed to the other input of the device compared I'm 13.

When the frequency of the signals at both inputs coincides, the comparator 13 lights one of the direction indicators 10 depending on the coincidence of their phase.

Thus, according to the indication of the direction indicator 10, the presence and “direction” of leakage in the signal frequency mounting harness 11 are determined, which allows unmistakable movement towards a place with damaged insulation.

The algorithm for finding a place with damaged installation insulation is as follows: after connecting the frequency generator between the ground and a wire with damaged insulation (0-100 kOhm), the electrical measuring clamps of the selective receiver tuned to the signal frequency are put on the wire going from the generator to the power pole. At the same time, the direction arrow (or one of two colored LEDs) on the instrument housing lights up. Putting on the measuring pliers on the mounting harness, according to the indications of the light indicators - the ignition of the LEDs determines the presence of a signal frequency in the harness, and the color of the LEDs determines the direction of search - movement towards a place with damaged insulation (ground fault).

Claims (1)

A device for determining the location of insulation damage, including an audio frequency generator connected between the ground and a wire with a reduced insulation resistance, electrical clamps connected to a selective receiver, characterized in that the audio frequency generator contains a frequency and current phase converter, has a physical communication line and the selective receiver additionally includes a receiver of a signal transmitted through a physical communication line, a phase distortion compensator, a comparison device, indicators directions.

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