Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electrical power distribution systems and devices
Reexamination Certificate
1999-08-02
2001-04-17
Thompson, Gregory (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electrical power distribution systems and devices
C361S618000, C361S620000
Reexamination Certificate
active
06219225
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a gas insulated switch gear, particularly, a gas insulated switch gear with a potential transformer suitable for improving reliability.
A gas insulated switch gear includes a combination of a plurality of components such as a breaker, disconnecting switches, grounding switches, a potential transformer, and others, and a power supply conductor for electrically connecting these components to each other in a closed enclosure charged with insulating gas.
The gas insulated switch gear is superior in size reduction, insulation performance, and safety and therefore, is widely used in electric plants such as substations. As shown in Japanese Laid-Open Patent Publications 10-75513(1998), 60-187217(1985) and 60-18390(1985), the conventional gas insulated switch gear having a potential transformer includes connection conductors, disconnectors connected to the conductors, cable sealing ends connected to the disconnectors, an arrestor, one end of which is connected to the disconnectors and the cable sealing ends; a single phase potential transformer, one terminal of which is connected between the disconnector and cable sealing end disposed in one phase of three phases.
The potential transformer is enclosed in an airtight chamber together with a plurality of other components of the line unit, and therefore, the potential transformer is exposed to air when assembled to the gas insulated switch gear. A problem of reduced the reliability is caused because water and dust are attached to the windings of the potential transformer in proportion to the exposure duration to the air.
Additionally, when current flows through a conductor mounted in the line unit, a magnetic field occurs. The induced voltage is generated at the secondary side of the potential transformer by causing the magnetic field to interlink with the core of the potential transformer. As a result, the output is distorted.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a gas insulated switch gear by which it is easy to assemble the potential transformer to the line unit.
Another object of the present invention is to provide a gas insulated switch gear which reduces influence to the secondary output of the potential transformer by the magnetic field caused by the current flowing through the conductor disposed in the line unit.
Another object of the present invention is to propose a method for assembling a gas insulated switch gear in which it is easy to assemble the potential transformer to the line unit.
To accomplish these and other objects a gas insulated switch gear according to the present invention comprises:
a main bus unit;
a circuit breaker unit hermetically coupled to said main bus unit;
a line unit hermetically coupled to said circuit breaker unit and having a top plate with a hole for inserting a potential transformer, and
an adapter cover or plate mounting the potential transformer inserted into said line unit through the hole and being connected hermetically on the top plate.
The outboard width of the adapter cover is larger than the inboard width of the hole and the outboard width of the potential transformer is smaller than the inboard width of the hole.
To further accomplish objects of the invention, a gas insulated switch gear according to the present invention comprises:
a main bus unit;
a circuit breaker unit hermetically coupled to said main bus unit;
a line unit hermetically coupled to said circuit breaker unit and having a top plate with a hole for inserting a potential transformer,
an adapter cover mounting the, potential transformer inserted into said line unit through the hole and being connected hermetically on the outside of the top plate, the outboard width of said adapter cover being larger than the inboard width of the hole, and the outboard width of the potential transformer being smaller than inboard width of the hole.
To further accomplish the objects of the invention, a method of assembling a gas insulated switch gear according to the present invention comprises steps of:
connecting hermetically a main bus unit, a circuit breaker unit and a line unit;
inserting a potential transformer mounted on an adapter plate and enclosed in a transporting tank into the line unit through a hole of the top plate of the line unit;
and connecting hermetically the adapter cover or plate on the top plate.
To further accomplish the objects of the invention, a gas insulated switch gear according to the present invention comprises:
a main bus unit;
a circuit breaker unit hermetically coupled to said main bus unit; and
a line unit hermetically coupled to said circuit breaker unit, wherein the arrangement direction of a conductor for connecting a conductor joint mounted on an insulating support connected to said line unit with a cable sealing end disposed in the line unit coincides with a layer direction of the core of the potential transformer, and the winding of the potential transformer is wounded so as to be perpendicular to the core layer direction of the transformer.
To further accomplish the objects of the invention, a gas insulated switch gear according to the present invention comprises:
a main bus unit;
a circuit breaker unit hermetically coupled to said main bus unit; and
a line unit hermetically coupled to said circuit breaker unit, wherein the layer direction of the core of the transformer in the line unit coincides with the direction of the magnetic field generated by the current flowing through a main circuit which connects a conductor joint mounted on an insulating support connected to said line unit with a cable sealing end disposed in the line unit.
REFERENCES:
patent: 5898565 (1999-04-01), Yamauchi et al.
patent: 60-18390 (1985-01-01), None
patent: 60-187217 (1985-09-01), None
patent: 10-75513 (1998-03-01), None
Kida Junzo
Takahashi Kazuhiko
Tsuzura Keiichi
Yabuki Minoru
Hitachi , Ltd.
Mattingly, Stanger & Malur
Thompson Gregory
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