RU2247438C2 - High-voltage current transformer - Google Patents

Abstract

FIELD: electrical and power engineering; high power flow transmission and distribution.

SUBSTANCE: proposed current transformer has grounded housing accommodating winding-and-core assembly incorporating magnetic core carrying secondary windings disposed around one of primary winding conductors and secured on grounded housing. Two high-voltage bushing conductors are coaxially disposed. Primary winding conductors are coaxially arranged within grounded housing and interconnected by means of conducting disk. Magnetic cores and secondary windings are disposed around internal primary winding conductor and secured to grounded housing. Vibration dampers made of insulating material are installed in high-voltage bushing between coaxial conductors.

EFFECT: enhanced reliability and dynamic resistance to short-circuit currents.

1 cl, 1 dwg

Description

The invention relates to the field of electrical engineering and energy in terms of transmission and distribution of electricity with a large flow of power and can be used to reduce the overall dimensions of the current transformer and improve operational reliability.

The known design of the current transformer type TFZM [1], made in the form of a tank structure with a U-shaped primary winding. The primary winding consists of one or more parallel aluminum or copper U-shaped conductors and is made as an input with capacitor plates.

The base of the transformer is a tank in which the cores with secondary windings are located. The insulator mounted on the lid of the tank is a high-strength porcelain tire. To ensure the operation of the main insulation of a current transformer of the TFZM type, which is subject to aging, it is necessary to invest additional expensive insulating materials in the design of the main insulation and strictly monitor the condition and level of transformer oil. In the process of manufacturing a current transformer, impregnation under high vacuum is necessary to eliminate moisture in the insulation and guarantee high dielectric characteristics. In addition, the transformer is fire and explosion hazard.

The closest technical solution to the proposed one is a current transformer [2], in which there is a grounded case with an active part containing magnetic cores with secondary windings located around one of the current conductors and mounted on a grounded case. The primary winding is made in the form of a loop. In the high-voltage input are two conductors located coaxially relative to each other. The presence in the earthed housing of the primary winding in the form of a conductor loop requires several insulators fastening the primary winding to provide dynamic resistance to short-circuit currents, which reduces the reliability of the structure and increases its size.

The aim of the invention is to increase the reliability, dynamic resistance to short circuit currents.

This goal is achieved by the fact that in a current transformer containing a grounded housing with an active part, including magnetic cores with secondary windings located around one of the primary conductors of the primary winding and mounted on a grounded housing and a high voltage input with two conductors located coaxially in the grounded housing, the primary conductors the windings are coaxial and interconnected by a conductive disk, while the magnetic cores and secondary windings are located around the inside primary conductors of the primary winding and are mounted directly to the grounded case, and in the high-voltage input between the coaxially located conductors are installed vibration dampers of insulating material.

The proposed device of the current transformer is shown in the drawing.

The high-voltage input consists of a sealed housing 1, which is under high potential, an insulator 2, coaxially arranged relative to each other conductors 3, insulating rings 4. In a grounded housing 5 are located coaxially to each other the conductors of the primary winding 6, which are interconnected by a conductive disk 7. The active part of the current transformer is installed around the internal conductor on the fastening elements 8: magnetic cores and secondary windings 9. Connection of input conductors with current conductors The primary windings of the current transformer located in the grounded casing are provided by the contact connector 10. In the grounded casing, an insulator 11 is used for attaching the conductors.

The operation of the current transformer is ensured by the passage of the primary current I ₁ through the conductors 3 and 6 and the disk 7 connecting them. The primary current creates an electromagnetic field in the magnetic circuit of electrical steel (or an alloy with high magnetic permeability). This field induces an electromotive force in the turns of the secondary winding 9. When 9 loads (ammeters, electric meters, relays, etc.) are connected to the terminals of the windings, a secondary current I ₂ flows in them.

Since the conductors of the primary winding of the current transformer are coaxial and interconnected by a conductive disk, the dynamic forces on these conductors during the passage of the short circuit current will be negligible. This allows you to minimize the number of fixing insulating elements. Together, these features of the proposed solution reduce the risk of damage during short circuit current and reduce the likelihood of damage to solid insulation as a result of partial discharges and electrochemical aging processes.

Sources of information

1. VVAfanasyev, N.M. Adoniev, VVKibel and others. Current transformers. Energoatomizdat, Leningrad, 1989, p. 262.

2. Japan Application No. 63310105, cl. H 01 F 40/06, publ. 12/19/1988 (prototype)

Claims (1)

A high voltage current transformer comprising a grounded case with an active part including magnetic cores with secondary windings located around one of the primary winding conductors and mounted on a grounded case, and a high voltage input with two current conductors arranged coaxially, characterized in that the primary conductors are in a grounded case windings are located coaxially and are interconnected by a conductive disk, while the magnetic cores and secondary windings are located around the morning conductor of the primary winding and are attached to a grounded case, and in the high-voltage input between the coaxially located conductors are installed vibration dampers of insulating material.