JPS5923163B2 - Voltage detection device for gas insulated switchgear - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage detection device applicable to gas-insulated switchgear.

Generally, in a composite gas insulated switchgear, as shown in FIG. 1, for example, the busbar side and the line side are connected to overhead lines, so a bushing A is installed.

For safety of opening and closing operations, these switching devices are provided with an electrical interlock circuit between the insulation switch B, the disconnector C, and the grounding device D. For example, if the circuit breaker B is closed, the disconnector C cannot be opened or closed, and if the circuit breaker B is closed, the grounding device D cannot be closed.
For example, if the disconnector B is turned on, the disconnector B cannot be turned on. Furthermore, an indication (for example, a lamp display or a meter display) of whether the entire switchgear is energized is also necessary for safety reasons. Note that E is a gas cap for protecting the opening/closing device. These interlocks 15
The circuits and power indications require grid voltage as their power source. Therefore, it is necessary to install voltage measuring devices such as PT and PD. However, the conventional P-T can be used as a power source only for the inter-head knock circuit and power supply display.
, the use of PD leads to a cost 20 toup. Bushing PD, which is a conventional technique, can be considered as a solution to this problem. However, this bushing PD can only be used if the capacitance between the center conductor and the PD tap is several hundred PF or more, such as a bushing with an oil-impregnated paper structure.
It is difficult to detect voltage within a class 3 error range. Now, it is assumed that the gas bushing shown in FIG. 2 is used for the bushing A of the connection part with the overhead line of the composite gas insulated switchgear shown in FIG. 1. When using a gas bushing, for example, as shown in Fig. 2, the ground shield electrode 2 and voltage detection (P-D) tap shield electrode 3 provided around the center conductor 1 are covered with epoxy resin 4. Even if we consider a molded and integrated bushing with a voltage detection (P-D) tap 5, the capacitance on the high voltage side will be small unless the opposing area of the center conductor 135 and the ground shield electrode 2 is made extremely large. It will be less than IOPE. With this value of capacitance, it is difficult to use a resonant type PD, and an amplifier type PD must be used, which increases costs.

On the other hand, although the use of gas bushings in gas-insulated switchgear has advantages over oil-immersed bushings in terms of cost reduction, maintenance, and handling, it currently has a drawback in voltage detection.

The present invention has been made in view of the above points, and provides a voltage detection device for a gas insulated switchgear that uses a cylindrical epoxy capacitor for voltage detection and also serves as a gas cap.

The present invention will be explained below with reference to the drawings. In FIG. 3, F is a voltage sensing device consisting of an epoxy capacitor connected in parallel to an SF6 gas gap that protects the switchgear from lightning surges. The details of its structure are shown in FIG. The SF6 gas gap consists of a high voltage side electrode part H inserted and fixed into one open end of the metal body 6, and a ground side main electrode part 1.
It consists of

The high voltage side main electrode part H includes a cylindrical discharge electrode 8 at the tip of a hollow conical insulating spacer 7, and this discharge electrode 8.
Insert the hemispherical rod-shaped arc electrode 9 placed inside into one open end of the metal body 6, and insert the insulating spacer 7 into the metal body 6 so that the tip of the insulating spacer is located on the outside. It is constructed by fixing. Further, a plug-shaped external connection terminal 10 is formed integrally with the discharge electrode 8 and the arc electrode 9. The ground side main electrode part 1 is a hemispherical bar-shaped arc electrode 1 fixed to the inside of a metal plate 11 that closes the other opening of the metal body 6.
2 and an insulator 13 attached to the inside of the metal plate 11
It consists of a dead electrode 15 attached to an epoxy capacitor 14 which is fixed via a epoxy capacitor 14. This epoxy capacitor 14 is formed by molding opposing electrode plates 14a and 14b with a molding material 14c. Further, a trigger electrode 16 is provided on the outer periphery of the ground side arc electrode 12.
is fixed. In the circuit diagram shown in FIG. 5, the high voltage side capacitor used as a voltage detection device is a cylindrical epoxy capacitor 14, while one end of the PD tap 17 that connects the low voltage side capacitor is fixedly connected to the metal plate 11. and is insulated from the metal plate 11.

The interior of the main body, which is sealed by the metal body 6, the insulating spacer 7 for supporting the high voltage side main electrode portion H, and the metal plate 11, is filled with SF6 gas having excellent arc extinguishing ability and dielectric strength. Next, the effects of the present invention will be explained.

The voltage detection device F of FIG. 3 according to the present invention also serves as a protective gap device.

In addition, the epoxy capacitor 14 has a ground side discharge electrode 15.
It also plays the role of voltage sharing that determines the residual voltage between the electrode 12 and the arc electrode 12. Now, as shown in FIG. 5, a low voltage capacitor 18 is connected to the low voltage side drawn out from the voltage detection tap 17.
and load 2 through reactor 19 and transformer 20.
1 is connected. This low voltage circuit is equipped with an arrester 22 to protect against intrusion surges due to discharge of the protective gap.
is installed. Since the epoxy capacitor 14 on the high voltage side can be manufactured with a value of several hundred PF, voltage detection by resonance type is possible. In addition, as mentioned above, the voltage required for discharging the ground side discharge electrode 15 and the trigger electrode 16 can be made to withstand high voltage by using the low voltage side capacitor 18 and the transformer 20 that have a somewhat higher rated voltage. By doing so, it is possible to share a predetermined voltage. According to the present invention described above, there are the following effects.

(1) Since voltage can be detected using a cylindrical epoxy capacitor with a large capacitance, it is also possible to use a resonant PD, reducing costs and simplifying maintenance and handling. (
2) Since the protective gap is connected and arranged in parallel within the epoxy capacitor, the capacitor storage tank can be omitted and the device can be made more compact.

(3) By using an epoxy capacitor in SF6 gas, a predetermined capacitance can be obtained in a compact manner.

[Brief explanation of the drawing]

Fig. 1 is an electrical wiring diagram of a conventional composite gas insulated switchgear, Fig. 2 is a sectional view showing an example of gas bushing, and Fig. 3 is a sectional view showing an example of gas bushing.
4 is a front sectional view showing an embodiment of the invention, and FIG. 5 is a circuit diagram of the voltage detection device. A...Butsuing, B...Shiya disconnection,
C...Disconnector, D...Grounding device, E.
... Gas gap, F ... Voltage detection device, H ... High voltage side main electrode section, I ... Ground side main electrode section, 1 ......・Center conductor, 2...
Ground shield electrode, 3... Shield electrode for voltage detection tap, 4... Epoxy mold, 5...
...Voltage detection (PD) tap, 6...Metal body, 7...Insulation spacer, 8...Discharge electrode, 9...Arc Electrode, 10...
External connection terminal, 11...Metal plate, 12...
...Arc electrode, 13...Insulator, 14...
... Epoxy capacitor, 15 ... Discharge electrode, 16 ... Triker electrode, 17 ... Voltage detection tap, 18 ... Low voltage side capacitor, 1
9...Reactor, 20...Transformer,
21...Load, 22...Arrestor.

Claims (1)

[Claims] 1. In a gas-insulated switchgear connected to a voltage detection device and a protective gap, a cylindrical molded capacitor formed by molding opposing electrode plates is placed in a metal cylinder filled with insulating gas, and the capacitor is One plate is connected to the high voltage side energized conductor, the other plate is led out from the metal cylinder through an insulator, and inside the molded capacitor,
Voltage detection of a gas insulated switchgear in which a high voltage side discharge electrode connected to a high voltage side energized conductor and a low voltage side discharge electrode connected to the other electrode plate are arranged so that a gap is formed between the opposing electrodes. Device.