JPH0227273A - Discharge apparatus - Google Patents

Abstract

PURPOSE:To promote discharge by generating corona discharge at the time of discharge after the finish of a test by allowing a discharge projection to protrude by providing the protrusible discharge projection to the outer surface of a hollow almost spherical high voltage charge part. CONSTITUTION:A plurality of conductive discharge needles 5 are mounted to a high voltage charge part 4 so as to be capable of protruding above the outer surface of a shield ring 4a. The discharge needles 5 are usually received in the hollow part 4b of the ring 4a as a whole and a drive member 6 such as a spring or a magnet is provided in the hollow part 4b so as to allow the discharge needles 5 to protrude by remote operation such as remote control or a timer. A DC withstand voltage test is finished to enter discharge operation but the drive member 6 is operated to allow the discharge needles 5 to protrude to the outside of the ring 4a as shown by a dotted line. The charge accumulated according to the electrostatic capacity of a power cable C reaches the charge part 4 through a protective resistor R. At this time, corona discharge is generated at the leading end parts of the discharge needles 5 to discharge the accumulated charge to the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a discharging device for discharging charges accumulated after a DC withstand voltage test of a power cable or the like is completed.

[Prior Art] When a DC withstand voltage test is performed by applying a DC high voltage to a power test object such as a power cable, electric charges are accumulated in the test object, so it is necessary to discharge the test object after the test is completed. but,
If this discharge occurs rapidly, an oscillating surge voltage is generated, which may damage the cable or other object under test. Therefore.

Conventionally, the power supply section is allowed to discharge naturally for a while, and after a certain amount of discharge has occurred, the power supply section is grounded through an electric resistance to perform the discharge. However, such a discharge method relies on spontaneous discharge.

When the voltage is as high as 200 to 300 KV, it takes more than an hour to complete the discharge, resulting in extremely poor work efficiency and safety issues.

[Object of the Invention] An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional examples and to provide a discharge device that can perform a discharge operation safely and in a short time.

[Summary of the Invention] The gist of the present invention to achieve the above-mentioned object is to install a high-voltage charging part formed into a hollow approximately spherical shape made of a conductive material on an insulating support member, and to provide a discharge protrusion made of the conductive material. The discharge device is characterized in that an object can be protruded from the outer surface of the high-voltage charging section by remote control.

[Embodiment J of the invention The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is an explanatory diagram of a discharge method using a discharge device according to the present invention, in which a discharge device 1 has an insulating support member 3 upright on a stand z, and a hollow approximately spherical shape formed by a conductive material on top of the insulating support member 3. It has a structure in which a high-voltage charging section 4 made of a formed shield ring 4a is attached. As shown in FIG. 2, the high voltage charging section 4 is provided with a plurality of electrically conductive discharge needles 5 that can protrude onto the outer surface of the shield ring 4a. These discharge needles 5 have a needle-like body whose base portion has a thickness on the order of mm, and the tip portion has a radius of curvature on the order of pm. The discharge needle 5 is normally housed entirely in the hollow part 4b of the shield ring 4a, and is made to protrude by a remote control or a timer using a driving member 6 such as a spring or magnet provided in the hollow part 4b. It is configured. Note that in order to project the discharge needle 5 by remote control, as shown in FIG. 2, the drive member 6 having a signal receiving section is surrounded by a shield ring 4a made of a conductive material to block electromagnetic waves that serve as command signals. Therefore, a plurality of through holes 4C are provided in the shield ring 4a so that electromagnetic waves can enter the hollow portion 4b. As shown in FIG. 3, the upper part of the shield ring 4a is provided with a plurality of inlet/outlet holes 4d for the discharge needles 5, and the areas around these inlet/outlet holes 4d are designed to prevent corona discharge from occurring from these areas. When the discharge needle 5 is bent inward at a predetermined curvature and protrudes to the outside, the peripheral portion of the inlet/outlet hole 4d comes into contact with the wooden part of the discharge needle 5.

The insulating support member 3 is grounded via a grounding wire G as shown in Fig. 1, but the insulation resistance value of the insulating support member 3 was determined to be so large that leakage current could be ignored during the DC withstand voltage test. For example, in the case of testing a cable of several 100 KV, insulation of several 1000 MΩ is required. On the other hand, the high voltage charging section 4 is connected to a power cable C, which is a test object, via a protective resistor R, and a shielding layer of the power cable C is grounded via a ground line G.

First, during the execution of the DC withstand voltage test, the discharge needle 5 is housed in the hollow part 4b of the shield ring 4a, as shown by the solid line of 2nd rM. If this is done, corona discharge will hardly occur from the shield ring 4a, and an accurate pressure test can be performed as in the conventional case.

Next, when the DC withstand voltage test is completed, the discharge operation begins, and the drive member 6 is actuated by a remote controller (not shown) to move the discharge needle 5 to the outside of the shield ring 4a as shown by the dotted line in FIGS. 1 and 2. make it stand out. Charges accumulated according to the capacitance of the power cable C reach the high voltage charging section 4 via the protective resistor R. At this time, since the shield ring 4a and the discharge needle 5 are in contact with each other, a corona discharge occurs at the tip of the discharge needle 5, and the accumulated charge is discharged to the atmosphere. When applied to a 3 mm discharge needle 5, a corona discharge of 1 to 2 mA is obtained. Therefore, whereas the method using natural discharge required more than an hour of work time, this method requires approximately 1/2 the working time.
Discharge can be completed in about 10 hours.

In the embodiment, a method of ejecting the discharge needle 5 by electric remote control has been shown, but it is also possible to eject the discharge needle 5 remotely using ultrasonic waves, air pressure, or the like. Further, in the illustrated embodiment, the number of discharge needles 5 is three, but this number can be selected arbitrarily, and the greater the number, the faster the discharge will be. Further, in order to store the discharge needle 5 which has first protruded into the shield ring 4a, it may be possible to use remote control, but it is convenient to push it in manually.

FIGS. 4(a) and 4(b) show an embodiment in which a conductive loop-shaped discharge member 7 is installed on the outer surface of the shield ring 4a instead of the discharge needle 5 as a discharge protrusion. The structure of the parts is the same as in FIGS. 1 and 2. The loop-shaped discharge member 7 is formed by forming a piano wire or the like having a diameter of about 2 mm into a loop shape, and is attached so that the wood part of the plate is in close contact with the entrance/exit hole 4d of the shield ring 4a.

During the withstand voltage test, the loop-shaped discharge member 7 is pushed down onto the shield ring 4a by the driving member 8, such as a magnet, as shown by the broken line in FIG. Sometimes, the loop-shaped discharge member 7 is made to stand upright as shown by the solid line in FIG. 4 by the drive member 8, and discharge is performed from the loop-shaped portion into the atmosphere.

The discharge projections installed on the shield ring 4a in this way can have various shapes.

In the above embodiment, the shield ring 4a is formed of a closed curved surface with no gaps.

Through hole 4 for allowing electromagnetic waves to enter for remote control
However, in the case of the shield ring 4a having countless gaps, it is not necessary to provide the through holes 4c. It is also possible to insert and remove the discharge protrusion using the .

[Effects of the Invention] As explained above, the discharge device according to the present invention is provided with a protrusion for discharging that can protrude on the outer surface of the hollow, approximately spherical high voltage charging part, so that the discharging protrusion that can protrude from the outer surface of the hollow approximately spherical high-voltage charging part prevents the cause of discharge from occurring during the DC withstand voltage test. The discharge protrusion is housed so that it does not occur, and when discharging after the test, the discharge protrusion is made to protrude to generate a corona discharge and accelerate the discharge, so the discharge time can be significantly shortened. It is possible. Further, since the projecting operation of the discharge protrusion is performed by remote control or a timer, safety can be easily ensured.

[Brief explanation of the drawing]

The drawings show an embodiment of a discharge device according to the present invention. Figure 1 is an explanatory diagram of the discharge method, Figure 2 is a partial sectional view of the device, Figure 3 is an explanatory diagram of the protruding operation of the discharge needle, and Figure 4 (a).
, (b) is a configuration diagram of another embodiment. Symbol l is a discharge device, 2 is a pedestal, 3 is an insulating support member, 4 is a high voltage charging part, 4a is a shield ring, 4b is a hollow part,
4d is an entrance/exit hole, and 5 is a discharge needle. 6.8 is a driving member, and 7 is a loop-shaped discharge member. Drawings Figure 1, Figure 4 (Q) Figure 2 (b) Procedural amendment (voluntary)

Claims (1)

[Claims] 1. A high-voltage charging part formed into a hollow, approximately spherical shape made of a conductive material is installed on an insulating support member, and a discharge protrusion made of a conductive material can be protruded from the outer surface of the high-voltage charging part by remote control. A discharge device characterized in that: