JPH0261972A - Discharge gap - Google Patents

Abstract

PURPOSE:To reduce the rise of the lightning impulse discharge start voltage against the steep rising overvoltage and improve the protective effect by providing projections on the side faces of opposing discharge electrodes respectively. CONSTITUTION:The first and second electrodes 4 and 5 forming a discharge gap are arranged face to face on both opening sections of the cylindrical spacer 1 of a dielectric porcelain, a lightning impulse discharge occurs across the electrodes 4 and 5 when the high voltage is generated, the voltage rise is suppressed, and an electric equipment is protected from the high voltage. Projections 4a and 5a are provided on side faces of the electrodes 4 and 5 respectively, and partial discharges occur across the projections 4a, 5a and inside faces of the spacer 1 when the wave-form rise of the instantaneous overvoltage is steep. These discharges serve as a trigger, and a discharge occurs across the electrodes 4 and 5 with no delay. As a result, the lightning impulse start voltage rise is suppressed against the steep rising overvoltage, and the protective effect is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a discharge gap for protecting various electrical equipment from momentary overvoltages.

BACKGROUND OF THE INVENTION Conventionally, this type of discharge gap has been constructed as shown in the second factor. In FIG. 2, 1 is a cylindrical spacer made of dielectric ceramic. Reference numerals 2 and 3 are electrodes, respectively having discharge portions 2N and 3a. The electrodes 2 and 3 are attached to the openings at both ends of the spacer 10 so that the respective discharge parts 2N and 3a face each other within the spacer 1.

Regarding the conventional discharge gap configured as above,
The six operations will be explained below. Now electrode 2 and electrode 3
When a momentary overvoltage is applied between
A momentary overvoltage is also applied between the discharge portion 3a of the electrode 3 and the discharge portion 3a of the electrode 3. When the overvoltage exceeds a certain voltage, a spark discharge occurs between the discharge part 2a of the electrode 2 and the discharge part 3a of the electrode 3, and a current flows between the electrodes 2 and 3, suppressing the voltage rise. , will protect electrical equipment from overvoltage.

Problems to be Solved by the Invention In such a conventional configuration, when the instantaneous overvoltage waveform shows a steep rise, the response of the spark discharge is delayed, and the voltage at which the discharge starts (referred to as the lightning impulse discharge start voltage) increases. There is a problem in that it becomes expensive and the equipment to be protected cannot be protected. As a countermeasure to this problem, it has been a challenge to realize a discharge ganop in which the lightning impulse discharge starting voltage does not increase even in the case of a steep rising waveform.

Means for Solving the Problem In order to solve this problem, the present invention comprises a cylindrical spacer made of dielectric porcelain, a first electrode and a second electrode each having a discharge portion, A protrusion is provided on a straight part of the first electrode and/or a side surface of a discharge part of the second electrode, and the first electrode and the second electrode are arranged such that the discharge part faces each other within the spacer. The spacer is attached to the openings at both ends of the spacer.

With this configuration, even when an overvoltage with a steep rising waveform is applied, the potential difference between the spacer and the protrusion provided at the discharge portion of the first electrode and/or the discharge portion of the second electrode prevents the protrusion from occurring. Partial discharge occurs between the first electrode and the spacer, and this triggers a spark discharge between the first electrode discharge part and the second electrode discharge part, resulting in an increase in the lightning impulse discharge starting voltage. This will be suppressed.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a front sectional view of a discharge gap in one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a cylindrical spacer made of dielectric ceramic, which is similar to the conventional one. 4 is a first electrode, and 4a is a discharge part of the first electrode 4. A protrusion 4b is provided on the side surface of the discharge portion 4a. 5 is a second electrode, and 6a is a discharge part of the second electrode 5. A protrusion 6b is provided on the side surface of the discharge portion 5a. The first electrode 42L and the second electrode 5a are attached to openings at both ends of the spacer 1 so that the respective discharge parts 4b and tsb face each other within the spacer 1.

The operation of the discharge gap configured as described above will be described below. Now, when a momentary overvoltage is applied between the first electrode 4 and the second electrode 6, an instantaneous overvoltage is also applied between the discharge part 4a of the first electrode 4 and the discharge part 5& of the second electrode 5. Overvoltage is applied. Then, when the overvoltage exceeds a certain voltage, the discharge part 4a of the first electrode 4 and the second electrode 6
A spark discharge occurs between the first electrode 4 and the first electrode 4.
A current flows between the electrode 6 and the second electrode 6, suppressing the voltage rise,
Protect electrical equipment from overvoltage. Generally, when the waveform of overvoltage shows a steep rise, spark discharge between discharge parts is less likely to occur. However, in this embodiment, the first
of the discharge part 4 of the electrode 4 of.

A voltage of ×v Cv: overvoltage value] O is applied between the protrusion 4b provided on the IHt+ surface and the inner surface of the spacer 1, and since the gap between the protrusion 4b and the spacer 1 is narrow, partial discharge occurs here. Similarly, the second electrode 6
A voltage of ×v O is applied between the projection sb provided on the side surface of the discharge portion 6a and the inner surface of the spacer 1, and a partial discharge occurs here as well. These partial discharges act as a trigger, and the discharge part 4 of the first electrode 4
Spark discharge occurs between a and the discharge portion 52L of the second electrode 6. Therefore, the lightning impulse discharge starting voltage does not increase even in the case of a steeply rising overvoltage, and the protection effect for the protected equipment is improved.

FIG. 3 shows the lightning impulse discharge starting voltage-time characteristics of the conventional discharge gap and the discharge gap of this embodiment. In FIG. 3, B is the characteristic of the conventional discharge gap, and B is the characteristic of the discharge gap of this embodiment. In the conventional discharge gap, when the discharge time is short, that is, when the overvoltage rises sharply, the lightning impulse discharge starting voltage becomes very high. On the other hand, the discharge gap in this example is
When the discharge time is shortened, that is, when an overvoltage rises sharply, the lightning impulse discharge starting voltage only increases slightly.

In this example, the projections are provided on both the discharge portion of the first electrode and the discharge portion of the second electrode. Similar effects can also be obtained when a protrusion is provided on only one of the two.

Effects of the Invention As described above, according to the present invention, the spacer is composed of a cylindrical spacer made of dielectric porcelain, and a first electrode and a second electrode having a discharge portion, and the discharge portion of the first electrode is and/or a protrusion is provided on the side surface of the discharge part of the second electrode, and the first electrode and the second electrode are arranged in openings at both ends of the spacer such that the discharge part faces each other within the spacer. By attaching it to the
It is possible to realize a discharge gearing with a small increase in the lightning impulse discharge starting voltage and a good protective effect, and its practical effects are outstanding.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a discharge gap according to an embodiment of the present invention, FIG. 2 is a front sectional view showing a conventional discharge gap, and FIG. 3 is a front sectional view showing a discharge gap according to the embodiment shown in FIG.
FIG. 3 is a diagram showing the lightning impulse discharge starting voltage-time characteristic of the conventional discharge gap shown in the figure. 1... Spacer, 4... First electrode,
4a・mountain...discharge part of the first electrode, 4b...protrusion provided on the discharge part of the first electrode, 6...
...Second electrode, 6a...Discharge part of the second electrode, 6b...Protrusion provided in the discharge part of the second electrode.

Claims (1)

[Claims] It consists of a cylindrical spacer made of dielectric porcelain, and a first electrode and a second electrode each having a discharge portion, the side surface of the discharge portion of the first electrode and/or the discharge portion of the second electrode. a discharge gap, wherein a protrusion is provided on a side surface of the spacer, and the first electrode and the second electrode are attached to openings at both ends of the spacer such that the discharge portions face each other within the spacer.