JPS6182411A - Gas insulated potential transformer - Google Patents

Abstract

PURPOSE:To enhance iron resonance suppressing effect and to remove an excess space by mounting a saturable reactor as an iron resonance suppressor on a low voltage lead bushing seat, and connecting a low voltage coil with the lead bushing of the coil. CONSTITUTION:A saturable reactor is mounted to surround a low voltage lead bushing seat inside a tank of the low voltage lead bushing seat. Insulating plates 16 having a plenty of electric insulation are disposed at both ends of a saturable reactor 15 inside a tank 8 of the low voltage lead bushing seat 14, a plurality of clamping parts 18 are disposed on the outer periphery of a metal retainer 17 and the reactor 15, and mounted on the seat 14. Thus, the lead of the reactor 15 can be extremely shortened as compared with the conventional one. Therefore, the resistance value of the reactor 15 including the leads decreases to increase the resistance loss when the reactor 15 operates as an iron resonance suppressor increases, thereby enhancing the suppressing effect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas-insulated voltage transformer with improved mounting of a saturable reactor to suppress fero-resonance.

[Technical background of the invention and its problems]

An electromagnetic GIS (7!/s insulated switchgear) direct-coupled gas-insulated instrument transformer consisting of an iron core, a low-voltage coil wound around it, and a high-voltage coil coaxially wound outside the low-voltage coil. is, if the values of the ground capacitance of the GIS, the capacitance between the poles of the GIS interrupter C1, the primary converted resistance R of the potential transformer itself, the -order converted nonlinear inductance L, etc. satisfy certain conditions. Even if the high-voltage circuit is cut off by a circuit breaker due to ferroresonance, a voltage may be generated for a long time in the low-voltage circuit of the potential transformer connected to this high-voltage circuit. .

It is already well known that when this iron resonance occurs, an accident may occur in which relays and the like housed in the control panel are burnt out.

Conventional methods for preventing this iron resonance include: 1. Significantly reducing the magnetic flux density of the core at rated voltage, 2. Inserting a resistor in parallel with the load in the low-voltage circuit, 2. Inserting a saturable reactor in parallel with the load in the low-voltage circuit. Means such as insertion are adopted.

However, among the means to suppress these fero-resonances, ■
In order to reduce the core magnetic flux density, it is necessary to increase the core cross-sectional area, which increases the core weight, increases the number of parts supporting the core, and increases the size of the coil, tank, and overall voltage transformer. There are disadvantages such as increased space, installation space, and weight.

The method (2) of inserting a resistor in parallel with the load in the low voltage circuit is the same as connecting a high load to the low voltage circuit of a potential transformer, and has the disadvantage of worsening error characteristics.

Therefore, in order to make the voltage transformer more compact and lightweight, the method (2) of inserting a saturable reactor into the low voltage circuit is generally adopted.

However, since this saturable reactor is generally installed in the control panel or relay terminal box, it is necessary to secure space for installing the saturable reactor in the control panel or relay terminal box, and it is necessary to separate the saturable reactor from the voltage transformer. The resistance value including the lead wire up to the saturable reactor is large, and the resistance loss (V2/R) when the saturable reactor operates as a ferroresonance suppressor is small, resulting in a sufficient ferroresonance suppressing effect. There were disadvantages such as not being able to obtain

[Purpose of the invention]

The present invention eliminates the above-mentioned drawbacks, and its object is to provide a gas-insulated voltage transformer that can enhance the fero-resonance suppression effect and eliminate unnecessary space.

[Summary of the invention]

In order to achieve the above object, the present invention provides a gas-insulated instrument transformer of the GIS direct connection type, which comprises a low-voltage coil and an iron core wound with a high-voltage coil, housed in a metal case together with an electrically insulating gas. Finally, a saturable reactor as a ferro-resonance suppressor is placed inside or outside the low-pressure outlet bushing seat and connected to the low-voltage coil in the low-pressure outlet bushing box by the outlet bushing of the low-voltage coil.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a gas insulated voltage transformer according to an embodiment of the present invention. In a gas-insulated instrument transformer, a low-voltage coil 3 and a high-voltage coil 4 are coaxially wound around an iron core 2 formed in a closed circuit so as to interlink with the iron core 2 from the inside, and a high-voltage shield is placed around the outer periphery of the high-voltage coil 4. 5 is installed, and a grounding shield 6 is placed on the grounding part opposite to this high voltage shield 5. It is mechanically fixed using fastening parts such as bolts.

The transformer was held airtight from the outside air by a tank 8 made of gold PA, an insulating spacer 9 and a gasket (not shown), and one end of the high voltage coil 4 was airtightly attached to the insulating spacer 9. It is electrically connected to a high voltage terminal 10, and the high voltage terminal 10 is electrically connected to a bus bar of a GIS (not shown).

On the other hand, the other end of the high-voltage coil 4 is led out of the tank 8 through a grounding bushing (not shown) that is airtightly attached to the tank 8 and is grounded.

Further, the outlet wires Ja and Jb of the low voltage coil 3 are connected to a low pressure outlet bushing 11a provided on the side wall of the tank 8.

Electrically connected to JJb, low pressure outlet bushing box 12
It is drawn into the control panel or relay terminal box through the

On the other hand, in the space surrounded by the pace 7, the tank 8, and the insulating spacer 9, an insulating gas 13 with high electrical insulation properties such as sulfur hexafluoride (5F6) gas is filled at a specified pressure to transform the gas insulated instrument. The vessel is configured.

FIG. 2 is an enlarged view of the low pressure outlet bushing shown in FIG. 1, and is a sectional view of an embodiment in which a saturable reactor is installed inside the tank of the low pressure outlet bushing seat so as to surround the low pressure outlet bushing. .

In FIG. 2, the low pressure outlet bushing 11a.

11b airtightly passes through a low-pressure outlet pusher and seat 14 attached to the tank 8.

On the other hand, on the inside of the tank 8 of the low-pressure outlet bushing seat 14, insulating plates 16 with high electrical insulation properties are arranged at both ends of the saturable reactor 15. Fastening parts (bolts, etc.) 18
is placed on the low pressure outlet gashing seat J4. The lead wires of the saturable reactor 15 are electrically connected to the outlet wires 3IL and 3b of the low voltage coil 3 inside the tank 8 of the low pressure outlet bushings 11g and llb, respectively.

FIG. 3 shows an enlarged view of the low-pressure outlet bushing shown in FIG. 1, and shows an embodiment in which a saturable reactor is mounted outside the tank on the low-pressure outlet bushing seat so as to surround the low-pressure outlet bushing.

In FIG. 3, the low pressure outlet bushing lla.

11b airtightly penetrates the low pressure outlet bushing seat 14 attached to the tank 8, and the low pressure outlet bushing 11a,
llb are lead wires 3h and 3b of the low voltage coil 3, respectively.
are electrically connected.

On the other hand, on the outside of the tank 8 of the low-pressure outlet bushing seat 14, a saturable reactor 15 with a moisture-proof layer provided on the outermost periphery is provided with an electrically insulating rubber sheet 18 with a small spring constant on both sides of the low-pressure outlet bushing box. 12 is watertightly attached to the low-pressure outlet bushing seat 14 via a gasket 19, thereby firmly mounting the saturable reactor 15 and covering the outside thereof. The lead wires of the saturable reactor 15 are electrically connected to the low pressure outlet bushings lla and llb on the outside of the tank 8, respectively.

The above configuration has the following advantages.

The first advantage is that the lead wire of the saturable reactor 15 is extremely shortened compared to the conventional one, so the resistance value of the saturable reactor 15 including the IJ-do wire is reduced, and the saturable reactor 15 suppresses fero-resonance. Since the resistance loss (v/R) increases when the device is operating, the suppressing effect can be enhanced.

The second advantage is that the saturable reactor 15 is attached to the conventional low pressure outlet bushing seat 14.
There is no need to install a separate mounting seat, and there is no need to increase the number of parts.

On the other hand, in the structure shown in the embodiment of FIG. 2, since the saturable reactor 15 is installed in a sealed gas, there is no need to change the attack method due to external environmental factors, and the saturable reactor 15 It can also have a great effect on standardizing the system.

In addition, in the embodiment shown in FIG. 3, the saturable reactor 15 is attached to the outside of the tank 8, so maintenance and inspection can be easily performed, and gas processing is also possible when attaching the saturable reactor 15 to an already delivered product. It also has the effect of being easy to install, even though it is not necessary.

In the above embodiment, the saturable reactor was installed on the inside of the tank or on the outside of the tank on the low pressure bushing seat, but even if it is installed inside the low pressure bushing box with a watertight structure, the saturable reactor, including the lead wires, Needless to say, the resistance value can be reduced and the same effect as shown in FIG. 3 can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the saturable reactor is attached to the low-voltage outlet bushing and connected to the low-voltage coil by the outlet bushing, so the resistance value including the lead wire can be reduced. Therefore, it is possible to obtain a gas-insulated instrument transformer which has a large fero-resonance suppressing effect and eliminates unnecessary space.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of a gas-insulated instrument transformer according to the present invention, FIG. 2 is an enlarged cross-sectional view of the low-pressure outlet bushing portion of FIG. 1, and FIG. FIG. 2 is an enlarged cross-sectional view of the low pressure outlet bushing portion of FIG. 1 according to an embodiment of the present invention; 1...Gas insulated instrument transformer, 2...Iron core, 3...
・Low voltage coil, 4... High voltage coil, 5... High voltage shield, 6... Ground shield, 7... Pace, 8...
-Tank, 9...Insulating spacer, 10-...High voltage terminal, 11a. 11b...Low pressure outlet bushing, 12...Low pressure outlet bushing box, 13...Insulating gas, 14...Low pressure outlet bushing, sing seat, 15...Saturable reactor, 16.
... Insulating plate, 17... Holding plate, J8... Rubber sheet, 19... Gasket, J a, 3 b...
Low voltage coil lead wire. Applicant's representative Patent attorney Takeshi Suzue Syllable 1 Figure $2a, 3゜

Claims (3)

[Claims] (1) A transformer in which a low-voltage coil and a high-voltage coil are coaxially wound around an iron core is housed in a metal tank along with insulating gas,
In a gas-insulated instrument transformer in which a low-voltage coil is drawn out through a low-pressure outlet bushing provided on a low-pressure outlet bushing seat provided in a metal tank, a saturable reactor is attached to the low-pressure outlet bushing seat, and the low-voltage A gas-insulated instrument transformer characterized by being connected to a low-voltage coil with an outlet bushing. (2) The gas-insulated instrument transformer according to claim 1, wherein the saturable reactor is attached to the low-pressure outlet bushing seat inside the metal tank. (3) A gas-insulated instrument according to claim 1, characterized in that the saturable reactor is attached to a low-pressure outlet bushing seat on the outside of the metal tank, and the outside thereof is covered with a low-pressure outlet bushing box. transformer.