JPH0448083Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a grounding switchgear of a reduced type switchgear filled with an insulating medium such as SF ₆ gas.

2. Description of the Related Art In a reduced-sized switchgear, a main circuit is sealed in a metal container, and the main circuit is grounded by a grounding switchgear attached to the main body.
Although the original purpose of this grounding switchgear is to ground so-called main circuits such as non-voltage lines and busbar sections, the following performance may be required in addition to that. In other words, 1) the ability to switch on and off electromagnetic and electrostatic induced currents from adjacent operating circuits, 2) the ability to turn on live circuits in case of an emergency, and 3) the ability to switch on and off the ground for cable power transmission. For equipment,
The cable residual charge can be discharged by using a resistor input method. In switching the induced current, the grounding switch installed at the overhead wire entrance is responsible for switching the electromagnetic induction and electrostatic induction current brought about by the parallel installation of the power transmission system.

In addition, if a power transmission cable is directly grounded with residual charge, the sudden movement of charge will generate a reciprocating oscillatory surge in the cable core, and the core surge will be induced as a surge in the cable sheath. There is a risk of causing dielectric breakdown of the corrosion protection layer. As a measure to prevent such dielectric breakdown, there is a resistor injection method. This resistor input method discharges the cable residual charge to ground via a resistor.

A conventional resistance-connection type grounding switch will be explained with reference to FIG. 6. When the rotary lever 2 is rotated by the operating mechanism 1, the resistance grounding switch is connected to the upper end of the tall insulated operating rod 3a without going through the link 2a. Movable contact 3
contacts the resistive grounding fixed contact 5 attached to the bus bar 4, and most of the cable residual charge is discharged through the resistor 6. Thereafter, the direct grounding movable contact 7 at the upper end of the short insulated operating rod 7a comes into contact with the direct grounding fixed contact 8 attached to the bus bar 4, thereby grounding the bus bar 4. The bus bar 4, the movable contact for resistance grounding 3, the movable contact for direct grounding 7, and the resistor 6 are hermetically stored in a tank 9, and an insulating medium such as SF ₆ gas is sealed in the tank 9. ing. Reference numeral 10 denotes an operation unit sealed case.

Problems to be Solved by the Invention According to the above-mentioned conventional technology, the earthing switch has a resistance grounding movable contact 3 and a direct grounding movable contact 7 having a fixed distance and different heights. Since the earthing switch is constructed in such a way that these components are moved simultaneously, the grounding switchgear is large in size, has a large number of parts, is structurally complex, and has poor reliability.
In particular, since the reduced type switchgear is intended to be small and compact, it is desirable that the various devices to be housed in the tank 9 be as small and high-performance as possible. Further, the conventional grounding switch only has the function of discharging the cable residual charge, and does not have the function of switching on and off the induced current as described above.

Means and Effects for Solving the Problems In order to solve the problems of the prior art described above, the present invention provides a cable that is equipped with a resistive grounding contact, a resistor, and a puffer cylinder so that the residual charge of the cable can be discharged by a resistive grounding method. We provide a compact grounding switch that has the functions of both a grounding switch for power transmission lines and a grounding switch that can switch on and off electromagnetic induction current or electrostatic induction current from adjacent operating circuits (live lines). In a grounding switchgear that performs resistance grounding and direct grounding of the bus bar in stages in a closed container filled with an insulating medium, the first movable rod contact with a resistor connected to the ground conductor is connected. and a second movable bar contactor are arranged coaxially apart from each other, and a movable bar that is movable in the axial direction is brought into sliding contact with the pair of movable bar contactors, and the movable bar is inserted into the puffer cylinder. At the same time, the insulating medium compressed by the piston attached to the movable rod forms a nozzle and a communicating pipe section through which the insulating medium is spouted from a part of the movable rod. Therefore, it is configured so that it can freely come into contact with and separate from the second movable bar contactor.

According to this configuration, when one movable rod moves in its axial direction, the first movable rod contact first conducts with the bus bar and establishes resistance grounding, while the movable rod further moves. This enables step-by-step grounding in which the second movable rod contact conducts with the bus bar and directly grounds the ground. Further, when interrupting the induced current, the arc of the induced current is blown out by the insulating medium jetted from the nozzle, making it possible to interrupt the induced current.

Embodiment The present invention will be specifically explained below with reference to an illustrated embodiment.

Figures 1 to 4 are longitudinal side views, respectively; Figure 1 shows the resistive grounding state, Figure 2 shows the direct grounding state, Figure 3 shows the ungrounded state, and Figures 4 and 5 show the grounding state. Each figure shows the initial stage of ground release. In the figure, the 6th
The same reference numerals are used for parts that are the same as or common to the figures,
The redundant explanation will be omitted.

A pedestal 11 is fixed to the inner bottom of the tank 9 facing the operation unit sealed case 10, and a first movable rod contact 12 is fitted into the contact case 13 and fixed to the pedestal 11. contact case 13
One end of a puffer cylinder 14 made of an insulating material is fixed to the holder, and a contact case 16 in which a second movable rod contactor 15 is housed is fixed to the other end of the puffer cylinder 14. 17 is arc-resistant metal,
Second movable rod contactor 15 and puffer cylinder 14
It is interposed between. The pair of contact cases 13 and 16 each have a conductor 1.
8 and 19 are connected, and a resistor 6 is connected between these conductors. The conductor 19 is connected to a grounding wire 20, which penetrates the insulating seal 21, extends outside the tank 9, and is electrically connected to the ground.

On the other hand, a movable rod 22 passing through the first and second movable rod contacts 12 and 15 is provided so as to be movable forward and backward relative to the fixed contact 29 of the generatrix 4, and this movable rod 22 has a piston portion 23 in its approximate center. and a communication pipe portion 25 that communicates with the intake hole 24 opened directly below the piston portion 23 is bored in the axial center portion,
Further, the communication pipe portion 25 communicates with a nozzle 26 formed at the head end of the movable rod 22 and a nozzle 27 formed directly above the piston portion 23, respectively. Furthermore, the movable rod 22 is covered with an insulating cylinder 28 between the piston portion 23 and the head end. The insulating tube 28 is configured to have a withstand voltage between it and the ground potential parts such as the second movable rod contactor 15 and the contact case 16 even if the charging voltage of the bus bar 4 is reached when the movable rod 22 and the like are grounded by resistance. Ru. 30 is an arc-resistant metal insulating cylinder 2
It is interposed between the lower part of 8 and the movable rod 22. 3
Reference numerals 1 and 32 are arc-resistant metals that are stretched over the lower surface of the fixed contact 29 and the head end of the movable rod 22, respectively. Although not shown, the puffer cylinder 1
An intake/exhaust hole is provided at the upper end of the piston section 4 to allow an insulating medium to freely enter and exit the puffer cylinder 14 above the piston section 23.

Therefore, the operation of the above embodiment will be explained. When the grounding is released, as shown in FIG. 3, by rotating the insulated rotary lever 2 clockwise, the link 2a moves the movable rod 22 downward, and
The head end of is pulled into the contact case 16. Therefore, during the grounding operation, the rotary lever 2 rotates counterclockwise in the state shown in Fig. 3, and the link 2a
moves the movable rod 22 upwardly. Then, as shown in FIG. 1, the head end of the movable rod 22 comes into contact with the fixed contact 29. On the other hand, the movable rod 22
The second movable rod contact 12 is in contact with the second movable rod contact 15 through an insulating tube 28. Therefore, the charge remaining on the bus bar 4 is as follows: fixed contact 29 → movable rod 22 → first movable rod contact 12 → contact case 13 → conductor 18 → resistor 6
→ conductor 19 → ground wire 20 → (see solid line arrow in FIG. 1), and resistance grounding is achieved. When the rotary lever 2 further reaches its top dead center, the movable rod 2
As shown in FIG. 2, the movable rod 22 and the second movable rod contactor 15, which were in insulating contact, are electrically connected to each other at the head end of the second movable rod 22, as shown in FIG. Therefore, the bus bar 4 is connected to the fixed contact 2.
Direct grounding is achieved through the following route: 9→movable rod 22→second movable contactor 15→contact case 16→conductor 19→grounding wire 20 (see solid line arrow in FIG. 2).

Note that when the movable rod 22 is moving in the axial direction toward the fixed contact 29, the piston portion 23 moves up inside the puffer cylinder 14, so that the insulating medium present in the tank 9 flows from the nozzle 26 to the communication pipe portion 25.
and is sucked into the puffer cylinder 14 through the intake hole 24.

Next, when the ground is released from the state shown in FIG. 2, when the insulating tube 28 and the second movable rod contact 15 come into contact as shown in FIG. 4 after passing through the state shown in FIG. While an induced current arc 33 is generated between the arc-resistant metals 31 and 30, as shown in FIG. A current arc 34 occurs. However, when the movable rod 22 is pushed down, the puffer cylinder 14
The insulating medium at the bottom of the piston part 23 inside is compressed,
The air flows into the communication pipe section 25 from the intake hole 24 and is ejected from the nozzles 26 and 27. (See the dotted line arrows in Figures 4 and 5.) Therefore, the induced current arc 3
3 is blown out by the insulating medium ejected from the nozzle 27, and the arc 34 of the induced current is blown out by the nozzle 26.
They are each blown out in a short period of time by the insulating medium jetting out.

It is also possible to provide a small gear gap between the inner diameter of the puffer cylinder 14 and the outside of the piston portion 23, or to provide a sealing gasket on the outer periphery of the piston portion 23.

Effects of the invention According to the invention explained above, one movable rod 2
By moving 2 in the axial direction, resistance grounding and direct grounding are performed in stages, so the structure is simplified and reduced in size, and the reliability of operation is improved. Furthermore, the movable rod 22
While the puffer cylinder 14 is engaged with the movable rod 22, the piston portion 23, the intake hole 24 and the communication pipe portion 2
5 and nozzles 26, 27, the arcs 33, 34 of the induced current generated between the arc-proof metals 17, 30 and 31, 32 are blown out when the ground is released, so there is no contact with the ground potential, and the induced current is This has effects such as improved blocking ability. Therefore,
Since it is equipped with a closing resistor and the induced current can be switched on and off using the puffer cylinder, it becomes a grounding switchgear that has both the resistance closing function and the induced current switching function, making it ideal as a grounding switchgear for receiving power. Standardization of earthing switchgear is possible.

[Brief explanation of the drawing]

Figures 1 to 3 are longitudinal side views showing an embodiment of the present invention, with Figure 1 showing a resistive grounding state, Figure 2 showing a direct grounding state, and Figure 3 showing a grounding release state. , FIG. 4 and FIG. 5 are longitudinal sectional side views of essential parts showing the initial state of ground release, and FIG. 6 is a longitudinal sectional side view of a conventional example. 4... Bus bar, 6... Resistor, 9... Tank, 1
2...First movable bar contactor, 14...Puff cylinder, 15...Second movable bar contactor, 18,1
9...Conductor, 20...Grounding wire, 22...Movable rod,
23...Piston part, 24...Intake hole, 25...
Communication tube section, 26, 27... nozzle, 28... insulating tube, 29... fixed contact.

Claims (1)

[Scope of Utility Model Registration Claim] In a grounding switch that performs resistance grounding and direct grounding of a bus bar in stages in a closed container filled with an insulating medium, a piston part that slides inside a puffer cylinder made of an insulating material is connected to the puffer cylinder. is installed on a movable rod penetrating the movable rod in a slidable manner, an insulating cylinder is installed on the outer periphery of the movable rod at a predetermined position on the distal end side, and from a nozzle opened at the distal end of the movable rod, a position on the rear end side of the piston section is installed. A communicating tube portion is bored in the movable rod near the rear end of the insulating cylinder, and a nozzle is bored in the vicinity of the rear end of the insulating cylinder of the movable rod, and the nozzle is opened to the outside from the communicating tube portion. A first movable rod contactor that is electrically contacted with the movable rod and grounded through a resistor is installed at the rear end of the puffer cylinder, and a first movable rod contactor is installed at the tip of the puffer cylinder, and the insulating cylinder or the movable rod is installed at the tip of the puffer cylinder. A second movable rod contact is installed in electrical contact with the movable rod and is directly grounded, and a fixed contact for the movable rod is installed at the connection part of the busbar at the extension corresponding position of the movable rod. Reduced type earthing switchgear.