RU2433498C2 - Power transformer - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: transformer contains an active part, namely a magnetic circuit and windings. The active part is integrated in a tank filled with transformer oil. Integral current transformer or a group of current transformers are built in the tank on taps of one or more windings of the active part. The transformer comprises secondary electrical pathways. Each of the secondary electrical pathways is passed through a window of the related current transformer or the group of current transformers. The ends of each secondary electrical pathway are brought out on an external surface of the tank and isolated, e.g. by an bushing insulators. Only one end of each electrical pathway can be brought out on the external surface of the tank, while the second one is electrically connected to the tank on its internal surface.

EFFECT: simplified process of current transformer check and reduced check cost.

2 cl, 2 dwg

Description

The invention relates to power transformers designed to convert alternating current of one voltage into alternating current of another voltage of the same frequency in electrical networks.

A known power transformer containing an active part, namely a magnetic circuit and windings, is placed in a transformer tank filled with transformer oil, on the bends of the windings of which inside the tank there are built-in current transformers designed to control the loads and power of the relay protection of the transformer (1).

The disadvantage of this design of the power transformer is the complex and time-consuming process of checking built-in current transformers, associated with high economic costs.

The closest in technical essence is a power oil transformer containing the active part, namely the magnetic circuit and windings, placed in a transformer tank filled with transformer oil, on the outlets of the windings of which inside the tank are installed built-in current transformers or groups of current transformers (2). It is also characterized by a complex and time-consuming process of checking current transformers, associated with high economic costs. Verification is carried out on current transformers removed from the power transformer, and therefore the verification process includes draining part of the transformer oil from the transformer tank, dismantling the taps and current transformers. After checking current transformers, installation of current transformers, taps and adding transformer oil to the transformer tank is necessary. At the same time, during the service life of the power transformer, current transformers must be checked several times with a frequency of once every four years.

The aim of the present invention is to simplify the process of calibration of current transformers, reduce the economic costs of its implementation and simplify the design of the power transformer.

This goal is achieved by the construction of the known power transformer of additional current conductors, each of which is passed through the window of the corresponding current transformer or group of current transformers, and the ends of each of the additional current conductors are displayed on the outer surface of the tank of the power transformer and isolated from it, for example, through bushing .

This allows the verification of current transformers without removing them from the power transformer, and therefore, significantly simplify the verification process and reduce the economic costs of its implementation.

Simplification of verification of current transformers consists in the fact that labor-intensive operations such as draining part of transformer oil from the tank of the power transformer, dismantling the bends of the windings of the active part of the transformer and dismantling the current transformers, as well as installing current transformers, mounting the bends of the windings of the active part of the transformer are excluded from the verification process and adding transformer oil to the transformer tank after checking current transformers.

The current transformers are verified according to the claimed technical solution without removing them from the transformer by passing current from the power source through an additional current path that serves as the primary winding of the current transformer or group of current transformers by connecting the power source to the ends of the additional current path located on the outer surface of the power transformer tank.

The design of the power transformer is greatly simplified by the electrical connection of one of the ends of each additional current lead to the tank of the power transformer on the inner surface of the tank. In this case, only one of the ends of the additional current lead is output to the outer surface of the tank of the power transformer. At the same time, the calibration of the built-in current transformers is carried out by connecting the power source to the tank of the power transformer and to the end of the additional current lead located on the outer surface of the tank of the power transformer.

Comparative analysis with the prototype showed that the claimed power transformer is distinguished by the presence of new features, namely, its design contains additional current conductors, each of which is passed through the window of the corresponding current transformer or group of current transformers, and the ends of each of the additional current conductors are displayed on the outer surface of the power transformer tank and isolated from it, for example, through bushing, and one end of each additional conductors can be union of electrically to a power transformer on the inner surface of the tank vessel, and the other displayed on the outer surface of the tank.

Thus, the claimed power transformer meets the criteria of the invention of "novelty."

In the study of other well-known technical solutions in this field, technical features that distinguish the claimed object from the prototype were not identified, which ensures the claimed object meets the criterion of "significant differences".

Figure 1 and figure 2 shows schematically the taps of the winding of a power transformer with a group of built-in current transformers, cuts.

In Fig. 1, the power transformer contains a branch 1, a group of two built-in current transformers 2 and an additional current lead 3. The ends 4 and 5 of the additional current lead 3 are brought to the outer surface of the tank 6 of the power transformer filled with transformer oil 7, and are isolated from the tank 6 by means of passage insulators 8 and 9. To the ends 4 and 5 of the additional current lead 3 is connected to a current source 10.

In Fig.2, the power transformer contains a branch 1, a group of two built-in current transformers 2 and an additional current lead 3. The end 4 of the additional current lead 3 is brought to the outer surface of the tank 6 of the power transformer filled with transformer oil 7, and is isolated from the tank 6 by means of a bushing 8 The other end 5 of the additional conductor 3 is electrically connected to the tank 6 on the inner surface of the tank. At the end of 4 and tank 6, a current source 10 is connected.

An electric current is passed from a current source through an exemplary current transformer through an additional current lead 3, which serves as the primary winding of a group of current transformers 2, and the terminals of the secondary windings of current transformers are connected to a comparison device.

Verification of current transformers of power transformers in operation showed that the use of the claimed design of a power transformer can significantly simplify the process of verification of current transformers and obtain an economic effect of at least 150 ÷ 200 thousand rubles per power transformer.

Information sources.

1. GOST 12965-85 “Transformers power oil general purpose voltage classes 110-115 kV. Technical conditions. "

2. Antonov M.V., Gerasimova L.S. Technology for the production of electrical machines. Textbook for universities. - M.: Energoizdat, 1982, 512 p., P. 483, Fig. 31.9.

Claims (2)

1. A power transformer containing an active part, namely a magnetic circuit and windings, placed in a transformer tank filled with transformer oil, inside of which on-leads of one or more windings are installed built-in current transformers, characterized in that it contains additional current conductors, each of which is passed through the window of the corresponding current transformer or group of current transformers, and the ends of each of the additional conductors are brought to the outer surface of the tank of the power transformer and from insulated from it, for example, through bushings. 2. A power transformer containing an active part, namely a magnetic circuit and windings, placed in a transformer tank filled with transformer oil, inside of which are installed built-in current transformers at the taps of one or several windings, characterized in that it contains additional current conductors, each of which is passed through a window of the corresponding current transformer or group of current transformers, with one end of each additional current lead brought to the outer surface of the power transformer tank RA and is isolated from it, for example, through a bushing, and the other is electrically connected to the tank of the power transformer on the inner surface of the tank.

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