RU201395U1 - CONSTRUCTION OF THE SHUNT FOR DIAGNOSTICS OF SUSPENDED INSULATORS OF AIR POWER LINE - Google Patents

Abstract

A design of a shunt is proposed, which is a resistance for the passage of an electric leakage current in an electric circuit, which is made in the form of a rod of semiconducting material, both ends of which pass into toroidal thickenings with metallized inserts, to which are fixed on one side - a traverse on which the diagnostic device is located , and on the other hand - an insulator, the contacts for removing the voltage drop from the leakage current of the insulator are the lower metallized insert of the toroidal thickening of the shunt, connected to the terminal contact of the diagnostic device using a wire, and the terminal contact, connected by a wire to the traverse. The design of the shunt is located on the support of the overhead power transmission line and is intended for diagnostics of overhead power transmission line insulators. The design of the shunt allows you to measure the leakage current under voltage, and, consequently, to diagnose 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 system with grounded neutral or a single-phase earth fault in a system with an isolated neutral. 2 ill.

Description

The device relates to the electric power industry, namely to diagnostics of insulators of overhead power lines (OHL) and is designed to monitor the leakage current under the load of OHTL, in order to detect damage to insulators and prevent possible short circuits in the power system.

In electrical engineering, 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). Known shunt - a device that allows an electric current (or magnetic flux) to flow bypassing any part of the circuit, usually a low-resistance resistor, coil or conductor. However, such a system is not used to measure the leakage current of overhead power transmission line insulators.

The objective of the present invention is to design a shunt for suspended insulators on overhead transmission lines for the possibility of measuring the leakage current under voltage, and, consequently, diagnostics of insulators in order to determine the presence of defects at the initial stage, which will lead to its timely replacement. Thus, it will prevent damage to the suspension insulator resulting in a short circuit in a grounded neutral system or a single phase earth fault in an isolated neutral system. 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.

Suspension insulators are used on overhead power lines with voltages above 1000 V. Thanks to metal fittings (cap, rod), they separate the power lines from the support.

FIG. 1 shows the construction of a shunt for diagnostics of overhead power line suspension insulators.

FIG. 2 shows a part of the overhead transmission line support with suspended insulators and shunts in each phase attached to the traverses on which diagnostic devices are installed.

A shunt design is proposed for monitoring the leakage current for suspended insulators, placed on an overhead power transmission line (OHL) support, having the shape of a rod 1 made of a semiconducting material, both ends of which pass into toroidal thickenings 2 with metallized inserts 3, to which they are fixed with one side - traverse 4, on which the diagnostic device 5 is located, and on the other side - the insulator 6, the contacts for removing the voltage drop from the leakage current of the insulator are the lower metallized insert of the shunt toroidal thickening connected to the terminal contact 7 (A) of the diagnostic device 5 when using wire 8 (A), and terminal contact 7 (B) connected by wire 8 (B) to crosshead 4.

The shunt design works as follows.

In normal mode, when the insulator 6 is serviceable and has a high resistance, the leakage current is within the normal range. This current flows from the power transmission line wire 9, through the insulator 6, through the shunt 10 to the grounded traverse 4. A voltage drop occurs on the shunt in accordance with Ohm's law, which goes to the diagnostic device 5 installed on the traverse 4. Since the leakage current is small, the diagnostic device 5 does not transmit a signal to the operator.

In the mode of damage to the insulator 6, its resistance decreases. The leakage current increases and reaches a critical value, and the voltage drop across the shunt 10 increases proportionally, which is controlled by the diagnostic device 5. Since the voltage on the shunt 10 corresponds to the alarm value, it will be recorded by the diagnostic device 5. The diagnostic device 5 is triggered and sends a signal to the operator ... This means that an unacceptably high voltage leak is diagnosed on the overhead power line, the insulator 6 is damaged and requires replacement.

The proposed design of the shunt for diagnostics of suspended 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 system with grounded neutral or a single-phase earth fault in a system with an isolated neutral.

Claims (1)

The design of a shunt for diagnostics of suspended insulators of an overhead power line, characterized in that it has the shape of a rod made of semiconducting material, both ends of which pass into toroidal thickenings with metallized inserts in the holes, to the toroidal thickenings are fixed on one side - a traverse, on the other - an insulator , and the contacts for removing the voltage drop from the leakage current of the insulator are the lower metallized insert of the toroidal thickening of the shunt, connected to one of the terminal contacts of the diagnostic device by means of a wire, and the second terminal contact, connected by a wire to the traverse, on which the diagnostic device that receives the signal is located.

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