CN220710099U - Single-phase three-winding 220kV gas-insulated transformer - Google Patents

Abstract

The utility model relates to a single-phase three-winding 220kV gas-insulated transformer which comprises a transformer main body and a transformer coil structure arranged in the transformer main body, wherein the transformer coil structure comprises a single-phase iron core and three-winding transformer coils fixed on the single-phase iron core, and the three-winding transformer coils are coaxially sleeved outside the iron core in sequence from inside to outside. The single-phase three-winding 220kV gas-insulated transformer has large capacity and high voltage, and improves the reliability and safety of products on the premise that main performance indexes meet the national relevant standard requirements.

Description

Single-phase three-winding 220kV gas-insulated transformer

Technical Field

The utility model relates to the technical field of transformers, in particular to a single-phase three-winding 220kV gas-insulated transformer.

Background

SF6 gas is adopted for insulation and cooling of the SF6 gas, the product structure is basically the same as that of an oil immersed transformer, and the SF6 gas insulated transformer is an explosion-proof transformer with fire prevention, safety and high electricity reliability, and is very suitable for places with high requirements on fire protection and reliability and good environmental compatibility. The following advantages over mineral oil transformers are achieved:

1. flame and explosion protection performance

SF6 gas insulation transformer adopts SF6 gas as insulation and cooling medium, and SF6 gas is non-combustible gas, even if the inside of the transformer breaks down, decomposed substances are gas, the pressure in the box body can not rise sharply, and combustion explosion can not be generated.

2. Convenient installation and flexible layout

The gas-insulated transformer is completely assembled when leaving a factory, SF6 gas is injected into the gas-insulated transformer, vacuumizing is not needed at an installation site, and the SF6 gas is directly input into the transformation tank from the gas tank, so that no tools are basically needed, and the gas-insulated transformer is clean and rapid in charging. Meanwhile, the density of SF6 gas is only 1/60 of the density of insulating oil, and the viscosity is low, so that the pressure drop in the cooling pipe is small, and the cooler can be horizontally installed or vertically installed without a transformer, so that the layout of the cooler is quite flexible. The gas-insulated transformer does not need a conservator and pressure release equipment and does not need a partition wall, and meanwhile, SF6 gas density is higher than that of transformer oil, so that the gas-insulated transformer is concise and light.

3. Easy maintenance and inspection

Under the same environment, SF6 gas consumes much slower than the oil of the oil immersed transformer. The gas-insulated transformer does not need to use an on-line oil filtering device of an on-load voltage regulating switch, and meanwhile, does not need to be provided with an oil storage cabinet and pressure release equipment, thereby bringing convenience to maintenance and inspection.

4. Small occupied area

The gas-insulated transformer has simple and light structure, reduced height, reduced roof of the corresponding underground substation, no need of partition wall, small installation occupation area, full utilization of the whole space and reduced construction cost of the substation. These advantages are even more pronounced, especially when the gas-insulated transformer is used in combination with a gas-insulated switchgear.

5. Low noise

SF6 gas density is less than transformer oil density, and sound transmission is slower, and the sound that the middle iron core sent can transmit the jar body very little, and thus, the noise that gas insulation transformer produced is less than oil immersed transformer.

The existing SF6 gas-insulated transformer generally adopts double-winding arrangement with the capacity of three-phase 63MVA and below, the voltage combination is generally 110kV on the high-voltage side and 10.5kV or 35kV on the low-voltage side, and the main defect is that the transformer cannot realize the 'large-capacity' power transformation requirement and cannot realize one power input and two voltage outputs.

Disclosure of Invention

Aiming at the defects in the prior art, the utility model provides a single-phase three-winding 220kV gas-insulated transformer which has large capacity, high voltage, small occupied area and convenient transportation.

The utility model is realized by the following technical scheme:

the utility model provides a single-phase three-winding 220kV gas-insulated transformer, includes the transformer main part and sets up the transformer coil structure in the transformer main part, the transformer coil structure includes single-phase iron core and is fixed in the three-winding transformer coil on the single-phase iron core, three-winding transformer coil is from inside to outside coaxial sleeve locates outside the iron core in proper order.

In order to facilitate installation, the single-phase iron core is of a single-phase double-frame three-column structure, and the three-winding transformer coil is coaxially sleeved on a middle column of the single-phase double-frame three-column structure.

Preferably, the three-winding transformer coil comprises a low-voltage winding, a medium-voltage winding and a high-voltage winding which are coaxially arranged from inside to outside.

In order to ensure the insulativity among the windings, the low-voltage winding, the medium-voltage winding and the high-voltage winding are separated by a surrounding screen and a stay.

Furthermore, in order to improve the voltage distribution condition under the lightning impulse voltage, the high-voltage winding adopts a middle incoming line and is connected in parallel up and down.

In order to improve the heat dissipation effect, the single-phase three-winding 220kV gas-insulated transformer further comprises a cooling system, and the cooling system is connected with the inner cavity of the transformer main body.

The beneficial effects of the utility model are as follows:

the single-phase three-winding 220kV gas-insulated transformer has large capacity and high voltage, and improves the reliability and safety of products on the premise that main performance indexes meet the national relevant standard requirements:

the iron core adopts a single-phase double-frame three-column structure, the yoke part adopts a 53% proportion section, the transportation height is reduced, and meanwhile, the section of the yoke part is increased, so that the purpose of reducing magnetic density and further reducing the iron core loss is achieved;

the high-voltage winding adopts a middle incoming line and an up-down parallel connection, wherein the head end of the high voltage adopts a 2-section shielding structure, so that the voltage distribution condition under lightning impulse voltage is improved;

by introducing the design technical principle of the cooling system, the temperature rising performance of the product is ensured;

by adopting a stay, a purse screen, a cushion block and the like with low compression ratio, the line cake is prevented from loosening due to shrinkage of the cushion block after being vibrated by electromagnetic force; after the winding is pre-tensioned by adopting a hydraulic device, an insulation pressing block with adjustable thickness is additionally arranged at the weak part of the winding in the iron core window, so that the periphery of the winding is uniformly pressed, the stop pin can prevent the pressing block from displacement and falling off after being stressed, the whole running period of the device body can be effectively ensured not to be loosened, and the short circuit resistance bearing capacity of the winding is improved;

the E-class material is adopted for the insulating part contacted with the coil, so that the insulating heat aging process is delayed, and the service life of the transformer is prolonged.

Drawings

Fig. 1 is a schematic perspective view of a single-phase three-winding 220kV gas-insulated transformer according to the present utility model;

fig. 2 is a schematic structural view of a transformer body and a transformer coil structure according to the present utility model;

fig. 3 is a cross-sectional view of a transformer coil structure of the present utility model.

Detailed Description

The preferred embodiments of the present utility model will be described in detail below with reference to the attached drawings so that the advantages and features of the present utility model can be more easily understood by those skilled in the art, thereby making clear and defining the scope of the present utility model. The directional terms referred to in the present utility model, such as "up", "down", "front", "back", "left", "right", "top", "bottom", etc., refer only to the directions of the attached drawings. Accordingly, directional terminology is used to describe and understand the utility model and is not limiting of the utility model.

The single-phase three-winding 220kV gas-insulated transformer shown in fig. 1 comprises a transformer main body 1, a transformer coil structure arranged in the transformer main body 1 and a cooling system connected with an inner cavity of the transformer main body 1.

Specifically, as shown in fig. 2, the transformer coil structure includes a single-phase iron core 3 and a three-winding transformer coil 4 fixed on the single-phase iron core 3, the single-phase iron core 3 is a single-phase double-frame three-column structure, the yoke portion adopts 53% proportion section, the transportation height is reduced, the section of the yoke portion is increased at the same time, the purpose of reducing magnetic density and further reducing iron core loss is achieved, and the three-winding transformer coil 4 is coaxially sleeved on a middle column of the single-phase double-frame three-column structure.

Specifically, as shown in fig. 3, the three-winding transformer coil includes a low-voltage winding 401, a medium-voltage winding 402, and a high-voltage winding 403 coaxially disposed from inside to outside, where the low-voltage winding 401, the medium-voltage winding 402, and the high-voltage winding 403 are separated by a screen 406 and a stay 407, the screen 406 is provided with multiple layers, an inner insulating paper tube 404 is disposed at the inner side of the low-voltage winding 401, an outer insulating paper tube 405 is disposed at the outer side of the high-voltage winding 403, the high-voltage winding adopts a middle incoming line and an upper and lower parallel connection, and a high-voltage head end adopts a 2-section shielding structure, so as to improve the voltage distribution condition under lightning impulse voltage, and meanwhile, the upper and lower ends of the low-voltage winding 401, the medium-voltage winding 402, and the high-voltage winding 403 are sealed by an electrostatic ring made of E-stage aramid crepe paper, and the above structures are all made of E-stage materials, so as to delay the insulating heat aging process, thereby prolonging the service life of the transformer.

The single-phase three-winding 220kV gas-insulated transformer fills the blank of a high-capacity, high-voltage and nonflammable and explosion-proof transformer, and provides a new thought for the design of large-scale urban substations with dense population in China;

the single-phase 80MVA/220kV gas transformer has the capacity reaching 240MVA after three-phase combination, the voltage combination is 220kV on the high-voltage side, 110kV on the medium-voltage side and 10.5kV on the low-voltage side, and the functions of gas transformation of large capacity and two-way transformation are realized;

the high-voltage 220kV winding and the shielding wire are made of PET (polyethylene terephthalate) films, and a 2-section shielding structure is adopted at the head end, so that the voltage distribution under the action of lightning impulse voltage is improved;

the upper end part and the lower end part of the high-voltage 220kV winding are electrostatic rings made of E-class aramid crepe paper, so that the service life of an insulation system is effectively prolonged, and the service life of a transformer is prolonged;

the utility model relates to a three-winding transformer, wherein independent air passage designs are designed for each winding in an insulating structure, and the air passage sections are distributed and designed according to calculation results such as heating value, gas loss ratio and the like;

low-loss design of the voltage regulating winding: in order to realize on-load voltage regulation and reduce the minimum tapping heat, a coarse-fine regulation mode is adopted, a coarse regulation winding of the coarse-fine regulation transformer is split from a high-voltage winding, the sum of load losses of the high-voltage winding and a coarse regulation winding of the coarse-fine regulation transformer is basically equal to the load loss of the high-voltage winding of the positive-negative regulation transformer, so that when in negative tapping operation, the load loss of the coarse-fine regulation transformer is smaller than the load loss of the positive-negative regulation transformer due to the fact that one coarse regulation winding is omitted, the load loss of the coarse-fine regulation transformer is reduced by about 7% compared with the load loss of the positive-negative regulation mode of the oil-immersed power transformer, the product temperature rise design is greatly facilitated, meanwhile, about 5% of heat radiator is saved, and the product performance is improved and meanwhile the cost is saved;

the temperature rise distribution in the winding is calculated by the technical means, and the difference is made between the positions with larger heating value and the positions with lower heating value, and different insulating part models are used at different positions of the winding, so that the service life is prolonged, and the aims of reducing the cost and enhancing the efficiency are fulfilled;

it should be noted that, the present utility model is not related to the part that is the same as or can be implemented by the prior art.

In addition, in the description of embodiments of the present utility model, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "configured," "provided," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

The above examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model.

Claims (6)

1. The utility model provides a single-phase three winding 220kV gas insulated transformer, includes the transformer main part and sets up in the transformer coil structure in the transformer main part, its characterized in that: the transformer coil structure comprises a single-phase iron core and a three-winding transformer coil fixed on the single-phase iron core, and the three-winding transformer coil is coaxially sleeved outside the iron core in sequence from inside to outside.

2. The single-phase three-winding 220kV gas-insulated transformer according to claim 1, wherein: the single-phase iron core is of a single-phase double-frame three-column structure, and the three-winding transformer coil is coaxially sleeved on a middle column of the single-phase double-frame three-column structure.

3. The single-phase three-winding 220kV gas-insulated transformer according to claim 2, wherein: the three-winding transformer coil comprises a low-voltage winding, a medium-voltage winding and a high-voltage winding which are coaxially arranged from inside to outside.

4. A single-phase three-winding 220kV gas-insulated transformer according to claim 3, characterized by: the low-voltage winding, the medium-voltage winding and the high-voltage winding are separated by a screen and a stay.

5. The single-phase three-winding 220kV gas-insulated transformer of claim 4, wherein: the high-voltage winding adopts a middle incoming line and is connected in parallel up and down.

6. The single-phase three-winding 220kV gas-insulated transformer according to any of claims 1-5, wherein: the cooling system is connected with the inner cavity of the transformer main body.