JPS6086812A - Current transformer - Google Patents

Abstract

PURPOSE:To reduce leakage inductance, to facilitate support and to eliminate the change of magnetic characteristics by mounting a shielding vessel, which consists of a nonmagnetic good conductor approximately covering the whole circumference of a core and is connected to a current transformer supporter, between a secondary winding and the core. CONSTITUTION:A shielding vessel 8 constituted by copper, aluminum, etc. as a good conductor and a nonmagnetic material is fitted to the outer surface of an insulating tape 5 wound on a core 4. A slit 8a is formed extending over the whole circumference of the shielding vessel 8 so that induced currents are not generated by magnetic flux in the core 4. According to such constitution, the leakage flux PHI of a secondary winding can be reduced to a small value because it cannot penetrate the vessel 8 and does not pass through the core 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a current transformer used for detecting voltage and current in power transmission and distribution equipment.

[Prior art]

FIG. 1 is a side view of a conventional current transformer attached to a gas insulated bus bar, and FIG. 2 is a sectional view taken along the line 1--2 of FIG.

In these figures, il+ is a tank filled with insulating gas, a bus bar (2) is provided in the center of the tank (l), and a current transformer (3) is provided on the inner surface of the tank.

The current transformer (3) mainly consists of an iron core (4) installed around the bus bar (-order conductor) (2), an insulating tape (5) wrapped around the other side of the iron core (4), and a wire of the bus #jt +21. It is mainly composed of a secondary winding (6) that is divided and wound in the circumferential direction.

(la) The housing provided on the inner surface of the H tank is a plate, and this housing is a plate (la). Place the Ic current transformer (3), and support plate (7) for the entire tank fil K bolts ( 7a)
The current transformer (3) is fixed in the tank +11 by fixing the Ic L and tightening the insulating tape (6) between the secondary windings and the bolt (7b).

In such a configuration, the leakage magnetic flux (φ) passing through the iron core (4)
occurs as shown by the broken line in FIG. 1, and the leakage inductance exhibits a large value. Therefore, it was necessary to increase the cross-sectional area of the core to obtain the required magnetic flux. In addition, the iron core (4
) is held down to support it through the mechanically weak insulating tape (61), so the iron core (4) is strained due to the machining of the plate (la), which deteriorates the magnetic properties. , there were drawbacks such as poor accuracy of the current transformer.

[Departure] Overview]

This invention was made in view of VC, and -
It is advantageous to provide a shielding container made of a non-magnetic good conductor that engages with the current transformer support between the iron core provided around the secondary conductor and the secondary winding wound around this iron core, and leakage inductance. The purpose of the present invention is to provide a current transformer which can be easily installed, can be supported without changing its excitation characteristics due to external force, and has a small amount of current.

[Embodiments of the invention]

The third factor is a side view showing one embodiment of the present invention, and FIG.
The ff-IV sectional view of the cause is shown. In these figures, +8
The outer surface of the insulating teeth' (51) wound around the 1H iron core (4) is a shielding container (8) that is a good conductor and is made of non-magnetic material such as copper or aluminum. Shield container + to prevent magnetic flux KL and induced current from occurring.
81 K H A slit (8a) is provided over the entire circumference. Also, between the secondary windings (6) there is a plate (
8b) is provided. A storage plate (1a) is also provided on the inner circumferential surface of the tank (1), but if multiple current transformers (3) are installed, they should be staggered in the circumferential direction and the bolts (
7b) Easy installation of VcL.

In addition, since the Ktd shield container (8) is provided between the iron core (4) and the secondary winding (6), the leakage magnetic flux (φ) of the secondary winding is as shown by the broken line in Fig. 3. Since it cannot penetrate the shield container (8) and the iron core (41) does not completely pass through, it has a small value. Therefore, the leakage inductance is reduced.Then, the cross-sectional area of the iron core through which the required magnetic flux passes can be reduced.

On the other hand, since the iron core (4) is made entirely of mechanically strong metal, it will not be distorted by forces during and after assembly. Therefore, there is no deterioration of magnetic properties, there is no need to have a core cross-sectional area with a margin in advance, and variations in accuracy are reduced.

FIG. 5 is a side view showing another embodiment of the present invention in which a high voltage is applied to the bus bar, and FIG. 6 is a sectional view taken along the line 1--2 in FIG. In these figures, it is a ttIu tank, and a flange (3A) is provided at the end of this tank +I+, and a support cylinder (1O) for a current transformer is provided between the flanges (1m) (la). This is a support plate that fully supports the current transformer attached to the outer periphery of the Hol t6 support cylinder (10), and is disposed between the support plate 1111fl secondary winding +61 and +61.

+121 H This is a bolt that defines the current transformer, and the support plate (11) is attached to the support plate 04, which is
1 is screwed on. (When multiple current transformers are installed, 151 is a gap fixing rod that is installed between the current transformers to determine the current transformer spacing, and one end is screwed to one shield container +81 K. In addition, in order to reduce the induced current due to the magnetic flux of the bus bar (2), the support plate [111K] is disposed close to the support plate [111K].

(8a) is a slit provided on the inner circumferential surface of the shield container (8) and engages with the support plate (Ill
Rotation of the current transformer is prevented by engagement with the current transformer.

With such a structure, the current transformer can be fixed without applying strain to the iron core (4), and leakage inductance can also be reduced.

〔Effect of the invention〕

As explained above, this invention is provided with a shield container between the secondary winding and the iron core, which is made of a non-magnetic good conductor that covers almost the entire circumference of the iron core and engages with the current transformer support, thereby reducing leakage inductance. Moreover, it is easy to support because it is not subjected to distortion due to external force from a supporting member, etc., and there is no change in magnetic properties, eliminating the need for a core cross-sectional area with a margin in advance.

[Brief explanation of drawings]

Figure 1 is a side view of a conventional current transformer, and Figure 2 is the ■- of Figure 1.
■Cross-sectional view, FIG. 3 is a side view showing one embodiment of the present invention, FIG. 4 is a cross-sectional view taken along the line IV-mV in FIG. 3, and FIG. FIG. 6 is a sectional view taken along line Vl-vi in FIG. In the figure, f411! Iron core, (6) is secondary winding, (8
) is a shielded container. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa "I-'l Figure 2

Claims (1)

[Claims] In a current transformer in which a secondary winding is divided and wound around an iron core provided around a primary conductor, a non-woven fabric covering almost the entire circumference of the iron core is placed between the secondary winding and the iron core. A current transformer comprising a shield container made of a magnetic good conductor and engaged with a current transformer support.