RU50713U1 - VOLTAGE TRANSFORMER - Google Patents

Abstract

The utility model relates to the field of electrical equipment, and specifically to voltage transformers designed to generate a measurement information signal for measuring devices in metering, protection and signaling circuits in 6-10 kV AC networks of industrial frequency with an isolated neutral or grounded through an arcing reactor. On the first magnetic circuit 1, the power windings of 2 measuring instruments are mounted. On the second magnetic circuit 3, windings 4 are installed for measuring and - protection. Magnetic cores 1, 3 are connected in a two-tier block, mounted on the cover 5, and are located inside the tank 8. To connect the transformer windings, contacts with insulators 9 installed on the cover 5 are used.

Description

The utility model relates to the field of electrical equipment, and specifically to voltage transformers designed to generate a measurement information signal for measuring devices in metering, protection and signaling circuits in 6-10 kV AC networks of industrial frequency with an isolated neutral or grounded through an arcing reactor.

Known three-phase three-winding voltage transformer with natural oil cooling. The transformer contains an oil-filled tank with a lid. The magnetic core with windings is mounted on the lid and immersed in oil. Insulators for connecting windings are mounted on the lid (see Petrov VN, Use of voltage transformers to connect dispatch control equipment to rural distribution networks, dissertation materials for the degree of candidate of technical sciences, Moscow, 1972, pp. 39-50).

The known transformer does not provide a protection circuit against resonant overvoltages in the case of single-phase faults and in the event of ferroresonance. Accordingly, the design of the transformer does not provide any means to provide protective functions.

The objective of the utility model is to develop the design of a voltage transformer, which allows to protect the transformer with single-phase faults and in the event of ferroresonance.

Mentioned protection can be implemented according to the scheme described in the USSR Author's Certificate No. 1319158, IPC 4 N 02 N 9/04, publ. 06/23/87.

This circuit provides for the electrical connection of two transformers to protect against resonant overvoltages of a voltage transformer in a network with isolated neutral.

The problem is solved by combining two transformers into a single structural unit.

The first three-phase three-winding transformer: the primary and main secondary windings are connected in a star circuit, the additional secondary windings are an open triangle. The transformer is designed to power the circuits of measuring instruments for accounting electric energy, for protection circuits and insulation control.

The second transformer of the zero sequence, two-winding, the primary winding of which is included in the neutral of the first transformer and is grounded. The secondary winding is displayed on the tank cap. This transformer is designed to protect the first from damage during single-phase faults and ferroresonance.

The protected design of the transformer provides for two magnetic circuit dialed from the plates, each of which is made of a double-rod armored type. On the first magnetic circuit, windings of two phases are mounted to power the measuring instruments, and on the second, windings of the third phase and windings for protection.

Magnetic cores are mounted in a two-tier block, which is located inside the tank and is mounted on the lid. Also on the cover are insulators with contacts for connecting the windings.

As an option, corners are fixed to connect the magnetic cores and the cover to them. Magnetic cores are connected to each other and to the cover by connecting corners mated by parallel protrusions in which holes are made for a threaded connection. The tank is filled with coolant, which is usually transformer oil.

An example of a specific implementation of the utility model is illustrated by drawings:

- figure 1 shows a General view of a voltage transformer, which conventionally shows a block of magnetic cores installed inside the tank;

- figure 2 shows the block of magnetic circuits, mounted on the cover on which the insulators are installed;

- figure 3 shows the connection of the magnetic cores between themselves and with the lid corners.

On the first magnetic circuit 1, the power windings of 2 measuring instruments are mounted. On the second magnetic circuit 3, windings 4 are installed for measurement and protection.

The corners 6 are fixed on the magnetic cores 1, 3 and on the cover 5. The magnetic cores 1, 3 and the cover 5 are connected to each other by connecting the corners 6, mated by parallel protrusions, in which holes for the threaded connection 7 are made.

The magnetic circuit block 1, 3 fixed on the cover 5 is located inside the tank 8, which is filled with transformer oil. To connect the transformer windings, contacts are used with insulators 9 mounted on the cover 5. The windings are wound with PETV wire 2. The windings for connecting the phases have a layered sectional design. Protective windings have a layered cylindrical design.

Claims (3)

1. A voltage transformer containing an oil-filled tank with a lid, two dialed magnetic circuit plates, each of which is made of a two-rod armored type, the windings of the two supply phases of measuring instruments are mounted on the first magnetic circuit, and the windings of the third phase are mounted on the second and for protection, the magnetic circuits are mounted in a two-tier block, located inside the tank and mounted on the lid, while insulators with contacts for connecting the windings are also installed on the lid. 2. The transformer according to claim 1, characterized in that the corners are fixed on the magnetic cores and on the cover, while the magnetic cores are connected to each other and to the cover by connecting the corners mated by parallel protrusions in which holes are made for a threaded connection. 3. The transformer according to claim 1, characterized in that the tank is filled with transformer oil.