JPH0261971A - 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 at opposing positions on the side faces of opposing discharge electrodes. CONSTITUTION:The first and second electrodes 2 and 3 provided with discharge sections 2a and 3a forming a discharge gap respectively are provided face to face on both opening sections of the cylindrical spacer 4 of a dielectric porcelain, a current flows between the electrodes 2 and 3 even if a spark discharge occurs across the electrodes 2 and 3 when the high voltage is generated, the voltage rise is suppressed, and an electric equipment is protected from the overvoltage. Opposing projections 4a and 4b are provided on the inside faces of the spacer 4 on the side faces of the electrodes 2 and 3 respectively, partial discharges occur across the electrodes and projections 2 and 4a and across 3 and 4b when the wave-form rise of the instantaneous overvoltage is steep, and a discharge occurs across the electrodes 2 and 3 with no delay using them as a trigger. As a result, the rise of the lightning impulse discharge start voltage 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.

Prior Art Conventionally, this type of discharge gap has been constructed as shown in FIG. In FIG. 2, 1 is a cylindrical spacer made of dielectric ceramic. Reference numerals 2 and 3 denote electrodes, each having a discharge portion 2a and 3&. The electrodes 2 and 3 are attached to openings at both ends of the spacer 1 so that the respective discharge portions 22L and 31L face each other within the spacer 1.

Regarding the conventional discharge gap configured as above,
The operation will be explained below. Now, when an instantaneous overvoltage is applied between the electrodes 2 and 3, an instantaneous overvoltage is also applied between the discharge section 2a of the electrode 2 and the discharge section 3a of the electrode 3.

When the overvoltage exceeds a certain voltage, the electrode 2
A spark discharge occurs between the discharge part 21L of the electrode 3 and the discharge part 3& of the electrode 3, and a current flows between the electrode 2 and the electrode 3, suppressing the voltage rise and protecting the electric 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 gap in which the lightning impulse discharge starting voltage does not increase even in the case of a steep rising waveform.

Means for Solving the Problems In order to solve this problem, the present invention comprises a substantially cylindrical spacer made of dielectric porcelain, and a first electrode and a second electrode each having a discharge portion, the first electrode and the second electrode such that the discharge portions face each other within the spacer;
It is attached to the openings at both ends of the spacer, and the inner surface of the spacer is located at a position opposite to the side surface of the discharge section of the first electrode. ! A protrusion is provided at a position facing the side surface of the discharge section of the second electrode.

Effect: With this configuration, even if an overvoltage with a steep rising waveform is applied, partial discharge will not occur between the protrusion provided on the inner surface of the spacer and the discharge portion of the first electrode and/or the discharge portion of the second electrode. occurs, and this serves as a trigger to generate a spark discharge between the discharge portion of the first electrode and the discharge portion of the second electrode, so that an increase in the lightning impulse discharge starting voltage is 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 Figure 1, 2 is the first 7F pole,
2a is a discharge part of the first electrode 2.

3 is the second electrode, and 38Lil''j is the discharge part of the second electrode 3.These are the same as the conventional one.4 is a substantially cylindrical spacer made of dielectric ceramic, 42L.

4b is a protrusion 3 provided on the inner surface of the spacer 4.
The discharge portion 2a of the first electrode 2 and the discharge portion 3a of the second electrode 3 are attached to openings at both ends of the spacer 4 so as to face each other within the spacer 4. Further, the protruding portion 4N is provided at a position facing the side surface of the discharge portion 2a of the first electrode 2, and the protrusion portion 4b is provided at a position facing the side surface of the discharge portion 3a of the second electrode 3. The operation of the gap will be explained below. Now, the first electrode 2
When a momentary overvoltage is applied between the first electrode 3 and the second electrode 3, the first
A momentary overvoltage is also applied between the discharge portion 2a of the second electrode 2 and the discharge portion 3a of the second electrode 3. Then, when the overvoltage exceeds a certain voltage, a spark discharge occurs between the discharge part 21a of the first electrode 2 and the discharge part 3a of the second electrode 3, and the first electrode 2 and the second electrode 3 A current flows between them, suppressing the voltage rise and protecting 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 example,
A voltage of XV (V: overvoltage value) is applied between the side surface of the discharge portion 2& of the first electrode 2 and the protrusion 4& provided on the spacer 4, and the side surface of the discharge portion 2a of the first electrode 2 and the protrusion 4& are applied. Since the gap between portions 4& is narrow, partial discharge occurs here.

Similarly, a voltage of xv Q is applied between the side surface of the discharge portion 31L of the second electrode 3 and the protrusion 4b provided on the spacer 4, and a partial discharge occurs here as well. These partial discharges act as a trigger, and the discharge part 2 of the first electrode 2
Spark discharge occurs between a and the discharge portion 31L of the second electrode 3. 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, character B represents the characteristics of a conventional discharge gap, and character B represents the characteristics of an unconventional discharge gap. 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, protrusions are provided both on the inner surface of the spacer at a position opposite to the side surface of the discharge section of the first electrode and at the inner surface of the spacer at a position opposite to the side surface of the discharge section of the second electrode. However, the same effect can be obtained even when the protrusion is provided at only one of the two positions.

Effects of the Invention As described above, according to the present invention, there is provided a substantially cylindrical spacer made of dielectric porcelain, a first electrode having a discharge portion, and a second electrode.
the first electrode and the second electrode,
The first electrode is attached to openings at both ends of the spacer so that the discharge parts face each other within the spacer, and the first electrode is located on the inner surface of the spacer at a position opposite to the side surface of the discharge part and/or the second electrode By providing a protrusion at a position facing the side of the discharge part, it can withstand sudden overvoltage rises.
It is possible to realize a discharge gap 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 of 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. 2...First electrode, 21L...Discharge part of the first electrode, 3...Second electrode, 3a...
... discharge part of the second electrode, 4 ... spacer,
4N, 4b... Protrusion. Name of agent: Patent attorney Shigetaka Awano and 1 other person1
Figure 3 / 1 a 3 Figure 2 Discharge time

Claims (1)

[Claims] It consists of a substantially cylindrical spacer made of dielectric porcelain, and a first electrode and a second electrode each having a discharge portion, the first electrode and the second electrode having a discharge portion facing each other within the spacer. attached to the openings at both ends of the spacer so as to face the spacer,
A discharge gap, characterized in that a protrusion is provided on an inner surface of the spacer at a position opposite to a side surface of the discharge section of the first electrode and/or at a position opposite to a side surface of the discharge section of the second electrode.