JPS60207316A - Stationary induction electric apparatus - Google Patents

Abstract

PURPOSE:To facilitate construction, and to check overheating of a tank according to leakage magnetic flux at a stationary induction electric apparatus by a method wherein a magnetic shield consisting of a ferromagnetic material is arranged to the trunk part of a high voltage electrostatic shield, and fixed to electric potential of the high voltage electrostatic shield. CONSTITUTION:After an insulating film 31 is coated on the electrode 30 of a high voltage electrostatic shield 4, a magnetic shield 20 is arranged to the trunk part on the opposite side from the tank of the high voltage electrostatic shield 4, and an insulating film 32 is coated thereon. Accordingly, the magnetic shield 20 is formed in a cylindrical type, while it can be constructed easily when a narrow paper tablet type magnetic shield unit or an amorphous metal tape, etc. are used, and moreover because the magnetic shield is arranged at the place regarded as dead space usually, size is not changed. Moreover, because leakage magnetic flux passes through the magnetic shield 20, a tank wall 1 is not overheated locally. When a breaking part to separate the magnetic shield as not to form a turn is made to coincide with the opposite part from the core of the high voltage electrostatic shield, heating of the tank due to leakage magnetic flux generated therefrom does not occur.

Description

[Detailed description of the invention] [Technical field of invention] The present invention applies static induction power to transformers, reactors, etc.

[Technical background of the invention and its problems]

As the capacity of stationary induction electric appliances such as transformers and reactors increases, the leakage flux of the coil also increases. Therefore, the amount of leakage magnetic flux entering structural materials such as the transformer tank increases, leading to increased loss due to eddy currents or problems of overheating due to eddy currents. In particular, because one side of the tank is in contact with air, its cooling effect is lower than that of oil, making overheating an even bigger problem. Generally, in large-capacity transformers, the tank wall (
Attach a magnetic shield (5) made of a ferromagnetic material such as a silicon steel strip or an electromagnetic shield made of a good conductor such as aluminum to the opposing part of the coils (2, 3) on the inner surface of the coil (2, 3). Leakage magnetic flux (6) is on the tank wall (1)
It prevents the intrusion. In order to further enhance the effect, a plurality of magnetic shields (5) are arranged in parallel on the tank wall along the direction of leakage magnetic flux, with narrow shield unit plates. (4) is a high voltage electrostatic shield.

This structure has the disadvantage that if the tank has a complicated broken line or curved shape, the shield unit must be installed separately for each part, making the work complicated.

In addition, there are some parts of the tank wall (1) where it is not possible to attach a shield, such as the outlet (through hole) for the outlet lead wire of the transformer, which may cause local overheating of the tank near the through hole, causing thermal decomposition or deterioration of the insulating oil. This also had the disadvantage of lowering the electrical resistance and impairing the reliability of the insulation.

[Purpose of the invention]

An object of the present invention is to provide a stationary induction electric appliance that is easy to work with and has a magnetic shield that prevents the tank from overheating due to leakage magnetic flux.

[Summary of the Invention] In order to achieve the above objects, the present invention provides a magnetic shield made of a ferromagnetic material in one body portion of a substantially cylindrical high-voltage electrostatic shield provided around the outer periphery of the outer winding. It is characterized by being fixed at the potential of the Seiden shield.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be explained by taking the transformer shown in FIG. 2 as an example, and the same parts as in FIG. 1 are designated by the same reference numerals. Generally, the electric field at the end of the outer winding (3) is relaxed to improve insulation performance. This high-voltage electrostatic shield (4) has a bulge shape at the top and bottom ends for the purpose of relaxing the magnetic field, so in conventional transformers, the part indicated by (10) suffers from dead space tear.

In the present invention, a magnetic shield (a) made of a ferromagnetic material is placed in this dead space (20) so as not to form one turn with respect to the iron core. The details are as shown in Figure 3, after applying insulation coating to the electrode (to) of the high voltage electrostatic shield (4), the body part of the high voltage electrostatic shield (4) on the side facing the tank (outside) A magnetic shield (to) is placed on the top and an insulating coating cIz is applied.

In this way, according to the present invention, the magnetic shield is cylindrical, but it can be easily fabricated by using a strip-shaped magnetic shield unit or amorphous metal tape, and it can be placed in a place that was previously a dead space. Dimensions remain unchanged. Moreover, since the leaked magnetic flux passes through the magnetic shield (a), the tank wall (1) does not heat up at the M3 portion. If the prick part that separates the magnetic shield so that it does not form a turn is aligned with the core opposing part of the high-voltage electrostatic shield, the leakage magnetic flux from that part will not heat the tank.

Further, as shown in FIG. 4, if an electrode surface (4G) having the same potential as the high-voltage electrostatic shield (4) is placed outside the magnetic shield (7), the insulation performance is the same as that of a conventional transformer.

〔Effect of the invention〕

I can do that.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a conventional transformer, Fig. 2 is a cross-sectional view showing one embodiment of the present invention, Fig. 3 is an enlarged view of installation details of a magnetic shielding device, and Fig. 4 is a diagram showing another embodiment. It is a detailed enlarged view. (1)...tank (2,3)...winding (4)...
・High-voltage electrostatic shield (20)...Magnetic shield attorney Kensuke Chika (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 4 3θ 3/ 2/ 7r%-

Claims (2)

[Claims] (1) A magnetic shield made of ferromagnetic material on the outer surface of the body of the high-voltage electrostatic shield provided on the outermost side of the winding. (2) Approximately cylindrical iron on the outer surface of the magnetic shield (3)
Bridge that prevents the formation of one turn of magnetic shield