WO2014201791A1

WO2014201791A1 - Degaussing coil structure for three-main-column parallel transformer

Info

Publication number: WO2014201791A1
Application number: PCT/CN2013/086041
Authority: WO
Inventors: 冯争人; 刘东海; 韩凯
Original assignee: 山东电力设备有限公司
Priority date: 2013-06-20
Filing date: 2013-10-28
Publication date: 2014-12-24
Also published as: CN103337342A

Abstract

A degaussing coil structure for a three-main-column parallel transformer. The structure comprises a degaussing coil I (1) and a degaussing coil II (2) that are respectively wound on left and right side columns of the transformer, dotted ends of the degaussing coil I and the degaussing coil II being connected in parallel to form a degaussing coil group, and the two degaussing coils being wound in the same direction. The degaussing coil structure can achieve automatic tracking degaussing by means of output and input of an ampere-turn balanced current; for the two degaussing coils, the head ends are connected and the tails ends are connected, so that the induced electromotive forces in the transformer mutually counteract. The degaussing coil structure is of a simple structure, is easily implemented, can fully suppress the additional flux generated by a window-type current, and reduce the transformer loss.

Description

Degaussing coil structure applied to three main column parallel transformer

Technical field

The invention relates to the field of ultra-high voltage transformers, in particular to a degaussing coil structure applied on a three-column parallel transformer.

Background technique

In order to realize the transmission project of "Western Power East Transmission" and "Nortel Power Transmission" on a larger scale, the State Grid will inevitably require the power transformer manufacturing industry to further develop a 1000kV ultra-high voltage class, 1500MVA extra large-capacity single-phase autotransformer power transformer. . In view of the fact that the transmission end of the transmission project is mostly in the remote northwest and southwest regions or in the mountainous area, the transportation conditions are very poor. For the double-column parallel 1000kV/1000MVA UHV transformer, the transportation weight is 360t, and the transportation size is 9.1*4.6*5.0m. For the 1000kV/1500MVA UHV transformer, the transport weight is 480t and the transport size is 12.6*4.6*5.0m. Only the three-column parallel structure can reduce the transport height and ensure the 500t limit weight of China's transportation, 4.6m wide and 5.0m high. Extreme transport outer size.

Similarly, in the development of a single-phase auto-coupled UHV transformer, due to the insulation structure problem, it is necessary to design the high-voltage outlet on the high-voltage side, the medium-voltage and neutral-point outlets on the medium-low pressure side, resulting in a half-twisted line passing through the core window. The half-turned window through-window current excitation transformer iron yoke large frame will significantly increase the loss and noise of the transformer. Therefore, one of the difficulties in the famous manufacturing plants of several large transformers in China is to solve the technical problem of excitation of the half-turn line. When the high-voltage coil flows through the rated load current Ir, a half-turn through-window current bypasses the iron yoke and returns to the power supply side, and the half-twisted field ampoule formed by the high-voltage coil is equivalent to the no-load excitation amp, but cannot participate. The balance of the coils of the running coil is such that the excitation in the iron yoke produces "Φ half" (as shown in Figure 1). Since the transformer is hung on the power grid, the magnetic flux of the stem must conform to Faraday's law of electromagnetic induction E=4.44fWφ, so “φ half” cannot enter the stem, but only exists in the upper and lower iron yokes and the side pillars, forming a close in it. The circuit, and the cross section of the iron yoke is only 1/2 of the core column, which will seriously saturate the magnetic circuit of the iron yoke, thereby significantly increasing the load loss and noise of the transformer, causing the UHV transformer to fail to operate normally. The design of the UHV transformer And manufacturing can not be successful, it is impossible to have the successful operation of the UHV transmission project that is currently playing an active role in China.

Summary of the invention

In order to solve the above problems, the present invention provides a degaussing coil structure applied to a three-column parallel transformer according to the working magnetic flux of the transformer and the degaussing principle of the degaussing coil for the excitation of the half-turn line.

The degaussing coil structure applied to the three main column parallel transformer according to the present invention comprises a degaussing coil I and a degaussing coil II respectively wound on two left and right side columns of the transformer, and the degaussing coil I and the degaussing coil II are connected in parallel to form a degaussing In the coil group, the two degaussing coils are wound in the same direction. According to Faraday's law of electromagnetic induction, the core has a main magnetic flux generated by the high voltage winding and the low voltage winding, an additional magnetic flux generated by the windowing current in the half turn of the winding yoke, and an induced magnetic flux generated by the degaussing coil. . Since the additional magnetic flux generated by the windowing current cannot enter the main column, but only exists in the upper and lower iron yokes and the side column, a closed loop is formed therein, and the degaussing coil generates an induced magnetic flux according to the ampoule balance principle. Balanced, the induced magnetic flux and the additional magnetic flux are always opposite in the direction of the core, which can effectively suppress the additional magnetic flux generated by the windowing current and reduce the influence of the additional magnetic flux on the transformer.

For larger capacity power transformers, the additional magnetic flux generated by the half turn line will be larger. To further cancel the additional magnetic flux, it is necessary to increase the number of turns of the degaussing coil or increase the current of the degaussing coil to increase the induced magnetic flux. The overall size of the degaussing coil is too large. To reduce the size of the degaussing coil and reduce the current in each degaussing coil, it can be set in such a manner that the degaussing coil group has two sets, which are respectively disposed at the upper and lower ends of the core. And connected in parallel.

Preferably, the degaussing coil set is grounded to prevent a floating potential from being generated to avoid a discharge phenomenon.

When the invention is connected, the two degaussing coils of the same group are connected by the same name for the main magnetic flux of the transformer, and the short circuit is not formed for the main magnetic flux; and for the semi-twisted magnetic flux, two of the same group The degaussing coil will be transformed into a different name end connection, which will generate a short-circuit induced current, which will eliminate the magnetic flux of the half-turn line.

The degaussing coil structure of the invention can realize automatic tracking degaussing by using the ampere balance current one by one, the first end of the two degaussing coils is connected to the head end, and the tail end is connected to the tail end, so that the induced potentials in the transformer cancel each other out. The invention has simple structure and convenient implementation, and can sufficiently suppress the additional magnetic flux generated by the windowing current and reduce the transformer loss.

DRAWINGS

Figure 1 is a prior art excitation distribution diagram;

Figure 2 is a schematic structural view of Embodiment 1 of the present invention;

Figure 3 is a schematic structural view of Embodiment 2 of the present invention;

In the figure, 1, the degaussing coil I, 2, the degaussing coil II, 3, the main magnetic flux, 4, the additional magnetic flux, 5, the induced magnetic flux.

detailed description

Example 1

A degaussing coil structure applied on a three-column parallel transformer, as shown in FIG. 2, comprises a degaussing coil I1 and a degaussing coil II2 respectively wound on two side columns of the transformer, and the degaussing coil I1 is connected to the head end of the degaussing coil II2 The tail end of the degaussing coil I1 is connected to the tail end of the degaussing coil II2, and the two degaussing coils are connected in parallel to form a degaussing coil group, and the two degaussing coils are wound in the same direction. The degaussing coil set is grounded.

Example 2

A degaussing coil structure applied to a three-column parallel transformer, as shown in FIG. 3, comprises two degaussing coil sets respectively disposed at two ends of the core and connected in parallel. Each of the degaussing coil sets includes a degaussing coil I1 and a degaussing coil II2, and the two degaussing coils are respectively wound on the two side pillars, and the first end is connected to the head end, and the tail end is connected to the tail end. The two degaussing coils of the same group are wound in the same direction, and the two degaussing coil sets are grounded.

The high-voltage winding and the low-voltage winding of the core generate a main magnetic flux 3, and the window-through current in the half-turn line of the iron yoke generates an additional magnetic flux 4, the degaussing coil generates an induced magnetic flux 5, and the induced magnetic flux 5 and the additional magnetic flux 4 The direction of the core is always opposite, effectively suppressing the additional magnetic flux generated by the windowing current.

If the winding direction of the main winding coil is changed, the winding direction of the degaussing coil is also changed, thereby ensuring that the direction of the induced magnetic flux and the additional magnetic flux are always opposite.

Claims

1. A degaussing coil structure applied to a three-column parallel transformer, characterized in that it comprises a degaussing coil I(1) and a degaussing coil II(2) respectively wound on two left and right side columns of the transformer, and a degaussing coil I (1) A degaussing coil group is formed in parallel with the end of the same name of the degaussing coil II (2), and the two degaussing coils are wound in the same direction.

2. The degaussing coil structure applied to a three-column parallel transformer according to claim 1, wherein the degaussing coil group has two sets, which are respectively disposed at upper and lower ends of the core and connected in parallel.

3. A degaussing coil structure for use on a three-column parallel transformer according to claim 1 or 2, wherein said degaussing coil set is grounded.