RU2143762C1 - Liquid-filled transformer for rolling stock of high-speed railways - Google Patents

Abstract

FIELD: transformers mounted in under-car space. SUBSTANCE: transformer has main tank holding winding-and-core assembly 1, tank cover 2 with gas collection space 3, pipeline 4 connected to gas-filling compartment 5, and conservator 6. Pipelines are arranged between transformer tank and conservator and gas relay is mounted above tank cover elevation. In case gas escapes due to fault during transformer operation, it is accumulated in gas collection space 3. Persistent gas escape raises pressure within tank and compresses gas in space 3 so that it is forced to pipeline 4. Amount of gas in gas-filling compartment 5 is monitored by means of special instruments. EFFECT: reduced height of transformer. 1 dwg

Description

 The invention relates to the field of electrical engineering, namely to transformers placed in the car space, as a result of which a minimum height requirement is imposed on them. A known transformer containing a corrugated tank with a liquid dielectric, which can change its volume with temperature fluctuations [1]. Such transformers do not have an expansion tank, made in the form of one structural unit and located, as a rule, above the tank with the active part and therefore their size in height is minimal. However, transformers with corrugated tanks can only be used in stationary installations due to the relatively low rigidity of the tank walls.

 Also known are transformers sealed with a gas cushion, for example nitrogen [2], which acts as a compensator for changes in the volume of a liquid dielectric. Structurally, the volume that is filled with gas has dimensions in width and length equal to the dimensions of the transformer tank cap, and therefore the size of the transformer in height due to the gas cushion increases slightly; however, this solution is not acceptable for rolling stock transformers, as with accelerations that can reach 4q, it is possible to shift the liquid dielectric to one side of the tank. In this case, individual nodes of the active part and taps that are under the potential may be outside the liquid dielectric, which will lead to a breakdown of the transformer insulation and its failure.

 Closest to the claimed one is a transformer [3], filled with a liquid dielectric, containing a main tank with an active part and a lid, an expansion tank, a pipeline connecting the main tank with an expansion tank, a gas filling compartment connected to the pipeline, with the beginning of the pipeline at the top of the cap, the expansion tank is located above the main tank, and the pipeline connecting the two tanks comes directly from the cap of the main tank. The described transformer without any limitation solves the problem of compensating for changes in the volume of liquid dielectric in the main tank. However, the height of the transformer in this case is at least determined by the sum of the heights of the main tank, part of the pipeline and the gas relay. For rolling stock of high-speed railways, electrical equipment placed in the car space must be made with minimum height, and the traditional layout described above does not allow the design of a transformer taking into account the requirements.

 The aim of the present invention is to provide a transformer with a liquid dielectric with the lowest possible height.

 This goal is achieved by the fact that in a transformer with a liquid dielectric containing a main tank with a lid, an expansion tank, a pipeline connecting the main tank with an expansion tank, a gas filling compartment connected to the pipeline, the beginning of the pipeline being in the upper part of the lid, it is proposed in the lid the main tank to fill the gas collection cavity, place the beginning of the pipeline inside the tank in the upper part of the gas collection cavity, withdraw the pipeline from the tank through its side wall, gas filling compartment with one with the pipeline after the pipeline is output from the tank wall.

 The need and sufficiency of these distinguishing features to achieve the goal is confirmed by the following. In transformers [3], a gas collection cavity is located in the pipeline. To ensure the passage of gases into the cavity, the orientation of the pipeline is upward, towards the expansion tank, which increases the size of the transformer in height.

 In the proposed transformer, the gas collection cavity is located in the cover of the main tank, the beginning of the pipeline connecting the tank with the active part with the expansion tank is placed inside the tank, the gas filling compartment is connected to the pipeline after it exits the tank wall and is within the height of the main tank . Thus, there are no structures above the cover of the main tank that could increase the height of the transformer.

 In the developed transformer with a capacity of 2000 kVA for rolling stock of high-speed railways, the permissible height size is 650 mm. If a part of the pipeline and a gas relay are placed on the tank lid, then the height of the transformer will increase by at least 250 mm, i.e. by 35%. In addition, this arrangement does not have access to service the gas relay, necessary during the operation of the transformer.

 In the inventive transformer, gas evolution is controlled using a gas collection cavity located in the tank cover and a gas filling compartment connected to the pipeline after it exits the tank wall.

 The drawing shows a diagram of the inventive transformer.

 The transformer contains a main tank with an active part 1, a tank cover 2 with a gas collection cavity 3, a pipe 4 connected to a gas filling compartment 5 and an expansion tank 6.

 During the operation of the transformer, in the event of gas evolution due to a malfunction, gas accumulates under the cover 2 and enters the cavity for collecting gas 3. In this case, the upper end of the pipeline 4 is in the gaseous medium. An increase in the temperature of the liquid dielectric or the continued evolution of gases increases the pressure in the tank, compresses the gas in the cavity 3, the gas is squeezed out into the pipeline 4 and is delayed in the gas filling compartment 5 in order to control its presence using appropriate devices.

 The proposed layout of the transformer allows to obtain a minimum size in height with the provision of gas evolution control.

Claims (1)

 A liquid dielectric transformer comprising a main tank with a lid, an expansion tank, a pipeline connecting the main tank to the expansion tank, a gas filling compartment connected to the pipeline, the beginning of the pipeline being in the upper part of the lid, characterized in that the main tank lid has a cavity for gas collection, the beginning of the pipeline is located inside the tank in the upper part of the gas collection cavity, the pipeline is withdrawn from the tank through its side wall, the gas filling compartment is connected to the pipeline after exiting and piping from the tank wall.