JPH065653B2 - Three-phase batch grounding type gas-insulated voltage transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a three-phase collective grounding type gas-insulated instrument transformer,
In particular, it relates to improvement of grounding means in a three-phase collective grounding type gas-insulated voltage transformer applied to a gas-insulated switchgear.

(Prior Art) A conventional three-phase collective grounding type gas-insulated instrument transformer (hereinafter abbreviated as three-phase gas PT) is a normal gas-insulated switchgear (hereinafter G
It is installed and connected to the IS (abbreviated as IS).
As shown in the horizontal cross-sectional view of the figure and the vertical cross-sectional view of FIG. 2, three-phase instrument transformer elements 4 in which a high-voltage winding 2 and a low-voltage winding 3 are coaxially wound around an iron core 1 and a metal container 5 The high voltage winding 2 is housed and enclosed together with an insulating gas 6 such as SF ₆ gas inside.
The conductors 7, 7a, 7b connected to one end of each of the three phases are connected to the respective lines 9, 10, 11 through the insulating spacer 8 and also connected to the other end of the high voltage winding 2. After the lead wires 12, 12a, 12b are collectively connected in the metal container 5, the lead wires 12, 12a, 12b are connected to the sealed structure terminal 13 electrically insulated from the metal container 5 and grounded together with the metal container 5 outside the metal container 5. Was.

(Problems to be Solved by the Invention) However, after the installation of the three-phase gas PT, if it becomes necessary to measure the insulation resistance between the phases in the GIS, the three-phase gas PT is once removed from the GIS, and the three-phase gas is removed from the GIS. The equipment is large because the high voltage circuit, such as disconnecting the collective grounding circuit or inserting a three-phase disconnector between the GIS and the pre-crisis GIS and opening this for measurement. However, the measurement of the insulation resistance is troublesome and causes a cost increase.

The present invention has been made in view of the above, and an object of the present invention is to integrally connect the ground side ends of the high-voltage windings of each phase to the outside of the metal container and ground them to provide insulation between the phases in the GIS. It is an object of the present invention to provide a three-phase collective grounding type gas insulation meter transformer capable of easily performing resistance measurement.

[Structure of Invention]

(Means for Solving the Problem) The ground side end of the high-voltage winding of the three-phase instrument transformer element housed in a metal container together with an insulating gas is electrically connected to the metal container and the ground side end of another phase. It is guided to the outside of the metal container through the electrically insulated sealed structure terminals of each phase, and the sealed structure terminals of each phase are connected to each other so that they can be connected to and disconnected from each other outside the metal container at the same time. Ground.

(Operation) The ground-side end of the high-voltage winding of each phase is electrically pulled out to the outside of the metal container through each sealed structure terminal, and the sealed structure terminals are connected together or the lead wires from the sealed structure terminals are connected together. And ground with a metal container.

When measuring the interphase insulation resistance of the GIS, disconnect the collective connection between the three phases at the sealed structure terminal portion outside the metal container.

Embodiment An embodiment of the present invention will be described with reference to the drawings. It should be noted that the same components as those of the above-described conventional technique are denoted by the same reference numerals and detailed description thereof will be omitted. In the cross sectional view of FIG.
A transformer element 4 for a three-phase instrument, which is formed by coaxially winding a high-voltage winding 2 and a low-voltage winding 3 on an iron core 1, is provided inside a metal container 5 with SF ₆
It is housed and enclosed together with an insulating gas 6 such as gas. One end of each of the high voltage windings 2 is connected to a bus conductor of a GIS (not shown) via the conductors 7, 7a, 7b. The other end of each of the high voltage windings 2 is separately drawn by the lead wires 12, 12a, 12b.
Then, a terminal plate 16 made of, for example, an insulating member is hermetically attached to the contact-side opening 15 formed in the metal container 5,
Further, the sealed structure terminals 13, 13a, 13b are attached to the terminal plate 16 in an airtight manner. The sealed structure terminals 13, 13a, 13b are electrically insulated from the metal container 5 and the lead wires 12, 12a, 12b of the other phase. The lead wires 12, 12a, 12b
Are separately connected to the sealed structure terminals 13, 13a, 13b and are electrically drawn out to the outside of the ground side opening 15, and on the outside, the sealed structure terminals 13, 13a, 13b are connected to each other so that they can be contacted and separated from each other. At the same time, it is connected to the grounding wire 17 so as to be able to come into contact with and separate from each other collectively, and the electric potential is set to the grounding potential together with the metal container 5. The ground-side opening 15 is covered with a lid 18 outside the sealed structure terminals 13, 13a, 13b.

Next, the operation of the above configuration will be described. When measuring the insulation resistance after installing the GIS directly connected to the three-phase gas PT between the GIS line and the ground, the sealed structure terminal 1 is provided outside the metal container 5.
It is sufficient to remove the grounding wire 17 that grounds 3, 13a and 13b together, and when carrying out between GIS phases,
The insulation resistance between the phases and between each line and ground can be measured by removing the connection between the sealed structure terminals 13, 13a and 13b.

〔The invention's effect〕

As described above, according to the present invention, in the verification test after the on-site installation of the GIS in which the three-phase gas PT is installed and connected, the three-phase gas P
By removing the connection between the ground terminals of the high voltage winding of T and between the grounds outside the metal container, there is an effect that the insulation resistance between the phases of GIS and the ground can be measured easily and economically.

[Brief description of drawings]

FIG. 1 is a horizontal cross-sectional view of a conventional three-phase collective grounding type gas-insulated instrument transformer, FIG. 2 is a longitudinal sectional view of the same, and FIG. 3 is a three-phase collective-grounded type gas-insulated instrument transformer of the present invention. FIG. 1 ... Iron core, 2 ... High voltage winding, 4 ... Transformer element for three-phase instrument, 5 ... Metal container, 6 ... Insulating gas, 7, 7a, 7b ... Conductor, 12, 12a, 12b ... Lead wire, 13, 13a , 13b ... Sealed structure terminal, 15 ... Ground side opening, 16 ... Terminal board, 17 ... Ground wire.

Claims (1)

[Claims] Claim: What is claimed is: 1. A transformer element for an instrument, which comprises an iron core for three phases and high-voltage and low-voltage windings wound around the iron core of each phase, is housed together with an insulating gas in the same metal container, and each of the phases is In the three-phase collective grounding type gas insulation instrument transformer in which one end of the high voltage winding of is connected to the line and the other end is grounded collectively, the ground side end of the high voltage winding of the iron core of each phase is It is guided to the outside of the metal container through the metal container and the sealed structure terminal of each phase electrically insulated from the ground side end of the other phase, and the sealed structure terminal of each phase is provided outside the metal container. A three-phase batch grounding type gas-insulated instrument transformer that is connected to each other so that it can be freely connected and disconnected, and is also grounded so that it can be connected and disconnected collectively.