RU204710U1 - CONSTRUCTION OF THE SHUNT FOR DIAGNOSTICS OF SUPPORT AND PIN INSULATORS OF AIR POWER LINE - Google Patents

Abstract

A shunt design is proposed for diagnostics of support and pin insulators of overhead power lines (OHL), which belongs to the electric power industry and is designed to monitor the leakage current under the load of OHTL, in order to detect damage to the support and pin insulators and prevent possible short circuits in the power system. A shunt structure, which is a resistance for the passage of an electric leakage current in an electrical circuit, containing a hollow cylinder made of a metal sheet not touching the crosshead, inside which a cylinder made of a resistive material is installed. In the upper part of the shunt structure, a metal cover with a bolt is fixed, on which an insulator is fixed. In the lower part of the cylinder made of resistive material, a bushing with an internal thread is inserted for attachment to the traverse, a diagnostic device with contacts for removing the potential difference is fixed to this traverse, one of its terminal contacts is connected with a wire to a hollow metal cylinder, and the second terminal contact is connected with a wire to the traverse. The proposed design of a shunt for diagnostics of support and pin insulators of overhead power lines allows measuring the leakage current under voltage, and, consequently, diagnosing insulators in order to determine the presence of defects at the initial stage, which will lead to its timely replacement. Thus, it prevents damage to the insulator with a short circuit in a grounded neutral system or a single phase earth fault in an isolated neutral system. 1 ill.

Description

A design of a shunt for diagnostics of support and pin insulators of an overhead power transmission line (OHL), which belongs to the electric power industry and is designed to monitor the leakage current under the load of an OHTL, in order to detect damage to the support and pin insulators and prevent possible short circuits in the power system, has been proposed.

In the electric power industry, a shunt is used to measure the current in a conductor flowing through it with a voltmeter (Demirchyan K.S., Neiman L.R., Korovkin N.V. Theoretical foundations of electrical engineering. Textbook for universities. 5th ed. - Publishing house "Peter", 2008. - T. 1. S. 142). However, such a system is not used to measure the leakage current of support and pin insulators of overhead transmission lines. A well-known shunt (from the English shunt -branch) - in measuring technology - a resistor or magnetic circuit connected in parallel with an electrical or magnetic measuring device to branch off a part of the electric current (magnetic flux) bypassing the device in cases where it is necessary to expand the measurement limits [Polytechnic dictionary / Redkol .: A.Yu. Ishlinsky (chief editor) and others - 3rd ed., Revised. and additional - M .: P50 "Great Russian Encyclopedia", 1998. - 656 p: ill. ISBN 5-85270-264-1].

The task of the proposed utility model is the design of a shunt for support and pin insulators on overhead transmission lines for the possibility of measuring the leakage current under voltage, and, consequently, diagnostics of support and pin insulators in order to determine the presence of defects at the initial stage, which will lead to its timely replacement. The proposed technical solution will eliminate damage to the support, pin insulator with the occurrence of a short circuit in a system with a grounded neutral or a single-phase earth fault in a system with an isolated neutral. At the same time, a feature of the shunt design is that it must have sufficient mechanical strength to withstand the static and dynamic load of wires and insulators of overhead transmission lines.

FIG. shows the design of a shunt for diagnostics of support and pin insulators of an overhead power line.

The design of the shunt 1 for diagnostics of the supporting and pin insulators of the overhead power transmission line, which is a resistance for the passage of an electric leakage current in an electrical circuit, containing a hollow cylinder 2 made of a metal sheet not touching the traverse for connecting the contact 3 of the diagnostic device. Inside the hollow metal cylinder 2, there is a cylinder 4 made of a resistive material. In the central upper part of the hollow cylinder 2, a metal cover 5 with a bolt 6 is fixed. In the lower part of the cylinder made of resistive material 4, a bushing 7 with an internal thread is inserted for attachment to the traverse.

The shunt design works as follows.

In normal mode, when the insulator is functional and has a high resistance, the leakage current is within the normal range. This current flows from the wire or the power line bus, through the insulator, through the shunt 1 to the grounded traverse. A voltage drop occurs across shunt 1 in accordance with Ohm's law, which is fed to the diagnostic device installed on the traverse. Since the leakage current is small, the diagnostic device does not work.

In the mode of deterioration of the state of the insulator, its resistance decreases. The leakage current increases and exceeds the critical value, and the voltage drop across shunt 1 increases in proportion to it, as a result of which the diagnostic device is triggered.

The proposed design of a shunt for diagnostics of support and pin insulators of an overhead power transmission line allows measuring the leakage current under voltage, and, consequently, diagnosing insulators in order to determine the presence of defects at the initial stage, which will lead to its timely replacement. Thus, it prevents damage to the insulator with a short circuit in a grounded neutral system or a single phase earth fault in an isolated neutral system.

Claims (1)

A shunt for diagnostics of support and pin insulators of an overhead power line, which is a resistance for the passage of an electric leakage current in an electrical circuit, characterized in that it consists of a hollow cylinder made of a metal sheet, not touching the crosshead, for connecting a contact of a diagnostic device, inside a hollow metal of the cylinder is a cylinder made of a resistive material, in the central upper part of which a cover with a bolt for attaching an insulator is attached; in the lower part of the cylinder made of a resistive material, a bushing with an internal thread is inserted for attaching to a traverse.

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