JPH0197109A - Earth opening and closing device - Google Patents

Abstract

PURPOSE:To reduce the number of parts and miniaturize a vessel, by a method wherein an insulating belt is provided on a movable contact rod and a sliding piece is positioned on the insulating belt after discharging the accumulated charge of an electric apparatus to be earthed to open impedance for discharging from an earth circuit. CONSTITUTION:A movable contact rod 42' is provided with an insulating belt 47 at a position where a sliding piece 44 is contacting with the movable contact rod 42' when a contact piece 46 and a projection 42'T are at contacting position. When switches 2, 3 are opened and an earth opening and closing device 4' is operated, the movable contact rod 42' contacts with a fixed contact 41. In this condition, a discharge opening and closing device 6 is closed, respective phases are short-circuited and respective phases of power cables 1, connected to the fixed contacts 41, are earthed by an earth rod 9 at the outside of a metallic vessel 10 through a discharging resistor 5'. When the movable contact rod 42' is moved further, the sliding piece 44 is positioned on the insulating belt 47 of the movable contact rod 42', the discharging switch 6 is opened and the earth switch 7 is closed whereby the earthing of cables 1 may be finished.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a grounding switchgear for electrical equipment such as capacitors and power cables.

[Conventional technology]

When repairing or inspecting telecommunications or electrical equipment, the live parts must be disconnected from the grid and grounded.

In this case, if electrical equipment such as capacitors and cables that are highly affected by residual charges are grounded directly or with low impedance, the accumulated charges will be instantaneously discharged.
The discharge current becomes oscillatory and generates abnormal voltage, which threatens the insulation of electrical equipment.

For this reason, in order to avoid this danger when fishing on a boat, a method has been adopted in which the residual charge is pre-discharged through a discharge resistor in the grounding circuit and then directly grounded.

Figures 7 to 9 are diagrams for explaining a conventional grounding switchgear equipped with a mechanism for discharging residual charges caused by a discharge resistor and its operating status. Figure 7 shows the state before operation of the grounding switch, Figure 9 shows the state after the grounding has been completed, and Figure 8 shows the situation during the process. It shows.

In FIG. 7(a), 1 is a grounded electrical device, which in this example is a power cable. 2 and 6 are switches for disconnecting the power cable from the power source (not shown) and the load, and 4 is a grounding switch, which is composed of a discharge resistor 5, a discharge switch 6, and a ground switch 7, and is connected to each phase. The switches 6 and 7 are configured to interlock with each other, and the specific configuration is shown in Fig. 7 (
(b) Shown in (b). In the same figure (b), 41 is a fixed contact;
Although not shown, they are electrically connected to each phase of the power cable 1, respectively. Reference numeral 42 denotes a movable contact rod that makes sliding contact with the fixed contact, and six phases are fixed together by an insulating support rod 46. Reference numeral 44 denotes a sliding piece, and the sliding pieces of each phase are commonly supported on the insulating rod 45 so as to be in constant contact with the movable contact rod 42. Reference numeral 46 denotes a contact piece, which is supported and fixed by a support (not shown) so as to come into contact with a protrusion 42T provided at its base when the movable contact bar 42 and the fixed contact 41 are in the final contact position. Specifically, each phase is led out of the metal container 10 by a grounding wire 46L via a bushing 8, and all six phases are grounded by a grounding rod 9.

The discharge resistor 5 is electrically connected between the sliding piece 44 and the contact piece 46 for each phase.

As mentioned above, Fig. 7 shows the situation before the switch 2 and 6 are opened for inspection of one cable 1 and the grounding switch is operated. When the operating device is operated, the movable contact rod 42 comes into contact with the fixed contact 41, and changes to the state shown in FIG. 8(6)(b). In this state, as shown in Figure (0), the discharge resistor 5 whose one end is grounded is connected to the fixed contact 41 via the sliding piece 44 and the movable contact rod 42, as shown in Figure (A). Like discharge switch 6
is in a closed state, and the electric charge in the power cable 1 is discharged through the resistor 5.

From the state shown in FIG. 8, when the movable contact rod 42 further moves to the left and the grounding switchgear reaches the final closing state lζ, the welding piece 46 moves to the movable contact as shown in FIG. 9(b). Bar 42
The fixed contact 41 bypasses the resistor 5 and is directly grounded, and the power cable 1 is completely grounded by the grounding switch 7, as shown in FIG. Ru.

In FIGS. 8 and 9, the same reference numerals as in FIG. 7 indicate the same parts. Furthermore, in FIGS. 7 to 9, the configurations of each phase are completely the same, so although only one phase has been described, the other two phases are also the same.

[Problem that the invention seeks to solve]

This type of grounding switchgear is usually housed in a metal container, so in order to inspect the internal status of each phase from outside the container, it is necessary to lead out the ground terminal for each phase outside the container. .

On the other hand, the discharge resistor is also housed in a metal container, but as mentioned above, it is necessary to lead out the ground terminal for each phase outside the metal container, so one resistor is used as the discharge resistor 5. It cannot be used commonly for all phases, and separate discharge resistors must be provided for each phase.

Therefore, there were problems in that not only six resistors were required, but also the size of the metal container housing them was unavoidable.

[Means to solve the problem]

This invention relates to a fixed contact connected to a grounded electrical device, and a movable contact that makes sliding contact with the fixed contact, whose base is integrally fixed by an insulating support rod, and a part of which is provided with an insulating band. The six phases are fixed together by an insulating rod, and a grounded sliding piece is connected to the outside of the container via a common discharge impedance for each phase. The contact piece f contacts the movable contact rod when the piece is positioned on the insulating band of the movable contact rod, and is grounded outside the metal container separately for each phase. is positioned on the insulating band provided on the movable contact rod when the grounded electrical equipment is grounded, and in this state, the contact with the movable contact rod is cut off and the discharge impedance is separated from the grounding circuit. This is what I did.

[Effect]

In this invention, an insulating band is provided on the movable contact rod, and after the accumulated charge of the grounded electrical equipment is discharged, the sliding piece is positioned on this insulating band, and the discharging impedance is separated from the grounding circuit. 6, only when the accumulated charge is discharged.
In addition to phase short-circuiting, it is possible to discharge with one common discharge impedance, which reduces the number of parts and the size of the metal container. The sliding pieces forming the 6-phase short circuit are:
Since it is separated from the grounded electrical equipment, not only the grounded electrical equipment but also the grounding switchgear itself can be inspected separately for each phase from outside the metal container.

〔Example〕

The present invention will be explained in detail below based on the embodiments shown in FIGS. 1 to 6.

In FIGS. 1 to 6, the same reference numerals as in FIG. 7 indicate the same components as shown in FIG.

In FIG. 1 (6), when the discharge 1 switch 6 is closed, an electric circuit is formed to form a 6-phase short circuit, and the circuit is connected via the discharge resistor 5'. The circuit configuration is the same as that in Figure 7 (a) except that it is configured to be grounded. The specific structure of the grounding switchgear 4' is as shown in FIG. 5′
It is led out of the metal container 10 via a bushing 8' and grounded by a grounding rod 9'.

Further, the movable contact rod 42' includes a contact piece 46 and a protrusion 42'.
An insulating band 47 is provided at the position where the sliding piece 44 and the movable contact rod 42' are in contact when the T is in the contact position, and the rest is the same as the conventional example shown in FIG. 7(b). .

Now, in order to inspect the power cable 1, I am trying to open the switches 2 and 6. When the operating device (not shown) of the earthing switchgear 4' is operated, the movable contact rod 42' comes into contact with the fixed contact 41, and the state changes to the state shown in Fig. 2A) (→).

In this state, the discharge switch 6 is closed, each phase is short-circuited, and each phase of the power cable 1 connected to the fixed contact 41 has one common discharge resistor 5'. The metal container 10 is connected to the ground via a ground ring 9' on the outside of the metal container 10. At this time, the contact piece 46 is not yet in contact with the protrusion 42''r, so the earthing switch 7 is in an open state.

Next, the movable contact rod 42' moves further, and when the operation is completed, the state shown in Figure 3 (A) 6:I) is reached. In this state, the sliding piece 44 is located on the insulating band 47 of the movable contact bar 42', and the contact piece 46 is located on the protrusion 47 of the movable contact bar 42'.
'T, the discharge switch 6 is opened and closed, and the grounding switch 7 is closed, as shown in FIG.

In this completely grounded state, the grounding wires 46L of each phase are led out to the outside of the metal container 10 independently of each other.

4 to 6 show other embodiments. In this embodiment, the movable contact bar 42'' (there is no protrusion and the contact piece 46 is always in sliding contact with the movable contact bar 42'' together with the sliding piece 44, but the insulating band 47', The relative positions of the sliding piece 44 and the contact piece 46 are determined, and the fixed contact piece 4
1 and the movable contact rod 42'', the contact piece 46 is located on the insulating band 47, and in the final stroke position of the movable contact rod 42'', that is, in the fully grounded state of the grounded electrical equipment, the sliding piece 46 is located on the insulating band 47. 4
4 are located on the insulating strip 47', and each is fixed in a relative position such that the contact piece 46 is in electrical contact with the movable contact rod 42''.

The earthing switchgear 4'' configured in this manner also exhibits the same effect as the embodiments shown in FIGS. 1 to 6 above. In other words, FIG. The switching device 4'' is in a state before operation, its electric circuit is in exactly the same state as the first time, and the discharge switch 6 and the earthing switch 7 are both in an open state. Next, when the movable contact rod 42'' is activated and comes into contact with the movable contact 41,
As shown in FIG. 5, the contact piece 46 is located on the insulating band 47', and in this state, as shown in FIG. is in a discharge state through the discharge resistor 5'. At this time, earthing switch 7
As mentioned above, since it is located on the insulating band 4/', it is in an open state. Next, when the movable contact rod 42'' is in the final closing position, that is, in the grounded state of the grounded device 1, the sliding piece 44 is located on the insulating band 47' as shown in FIG.
6 comes into contact with the movable contact rod 42'', and as shown in FIG. 6(a), the discharge switch 6 is opened and the ground switch 7 is closed, and the electrical equipment to be grounded is completely grounded. Electrically, the operation and effects are exactly the same as those of the embodiments shown in FIGS. 1 to 6.

In the above explanation, the charge accumulated in the grounded electrical equipment is discharged through a discharge resistor, but instead of this discharge resistor, another suitable impedance, for example, Of course, the discharge can also be performed using the impedance of a voltage detection voltage transformer provided on the line side.

〔Effect of the invention〕

According to this invention, only one impedance such as a resistor for discharging is required in common for six phases, which makes it possible to reduce the number of parts and thereby downsize the metal container. Can be independently led out of the metal container,
Various inspections of grounded electrical equipment can be performed for each phase from outside the metal container.

[Brief explanation of the drawing]

In the drawings, which are divided into (a) and (b), (a) shows the electric circuit diagram, and (b) shows the specific machine groove diagram. 1 to 6 are open state diagrams, intermediate state diagrams, closed state diagrams, and FIGS.
The figures show similar views showing another embodiment of the present invention, and FIGS. 7 to 9 show similar views showing a conventional example. 1... Electric cable 2,5. ,, Switch 4'
, 4"...Earthing switchgear 5.5'...Resistor 6...
・Discharge switch 7...Earth switch 41...Fixed contacts 42, 42', 42"...Movable contact bar 44...
Sliding piece 46... Contact piece 47, 47'...
insulation band

Claims (1)

[Claims] A fixed contact connected to a grounded electrical device, and a movable contact that makes sliding contact with this fixed contact, whose base has three phases fixed to one body by an insulated support rod, and a part of which is provided with an insulated band. A contact bar, a sliding piece that slides on the movable contact bar, has three phases integrally fixed to an insulating rod, and is led out to the outside of the metal container and grounded through a discharge impedance common to each phase; This sliding piece contacts the movable contact bar when it is positioned on the insulating band of the movable contact bar, and the contact piece is grounded outside the metal container for each phase.