JPH03172771A - High voltage measuring device - Google Patents

Abstract

PURPOSE:To make an adjustment of device easy and to measure a high voltage with high accuracy by providing a movable electrode plate held movably by receiving an electrostatically attracting force and a fixed electrode plate held so as to oppositely face the movable electrode plate. CONSTITUTION:The movable electrode plate 4 is assumed to be placed in the position same as the side wall of a gas tank 1. The movable electrode plate 4 is pulled toward the direction of high voltage terminal 2 by an electrostatically attracting force exerted between the side wall of gas tank 1 and the high voltage terminal 2. As the result, the electrostatic capacitance formed between the movable electrode plate 4 and the fixed electrode plate 5 is decreased. A resonance circuit 9 is formed by this electrostatic capacitance, and the resonance frequency is varied in accordance with the decrease of electrostatic capacitance. Then, the high voltage is measured by means of detecting the change of resonance frequency in the resonance circuit 9 by a frequency detecting circuit 10. By this procedure, the accurate voltage measurement is attained without requiring specially a precision resistor, etc.

Description

[Detailed description of the invention] [Industrial application field]

This invention applies to extremely high DC high voltages (for example, 200 KV to 200 KV) used in bump graphs, pelletrons, etc.
The present invention relates to a high voltage measuring device suitable for measuring 1 MV).

[Conventional technology]

As DC high voltage measuring devices, electrostatic voltmeters, rotary voltmeters, vibrating voltmeters, and devices that use high resistance as multipliers or voltage dividers are conventionally known. ” Maki Shoten, 2306-315).

[Problem to be solved by the invention]

However, among conventional high voltage measurement devices, electrostatic voltmeters, rotary voltmeters, vibration voltmeters, etc. all have mechanically movable structures, so they have problems with adjustment and lifespan.
It requires a larger installation space. In addition, in devices that use high resistance as a multiplier or voltage divider,
It is easily affected by leakage current and corona discharge and has accuracy problems. An object of the present invention is to provide a high voltage measuring device that has a simple structure, is free from problems in terms of adjustment and service life, and can measure high voltage with high accuracy.

[Means to solve the problem]

In order to achieve the above object, the high voltage measuring device according to the present invention includes a movable electrode plate that is held so as to be moved by receiving electrostatic attraction from a portion to which a high voltage is applied; A resonant circuit that includes a fixed electrode plate held to face each other, a capacitance formed between the movable electrode plate and the fixed electrode plate, and a circuit that detects changes in the resonant frequency of the resonant circuit. are provided.

[For production]

Generally, when a voltage V is applied between two opposing conductors, an electrostatic attractive force proportional to the square of the voltage ■ acts between the conductors. Therefore, the movable electrode plate is placed so that this electrostatic attraction force acts, the movable electrode plate is held so that it moves by the electrostatic attraction force, and the movable electrode plate is held so that it is opposed to this movable electrode plate. Hold the fixed electrode plate. Then, when the movable electrode plate moves due to the action of electrostatic attraction, the capacitance formed between the movable electrode plate and the fixed electrode plate changes. As a result, since this capacitance forms a resonant circuit, it appears as a change in the resonant frequency, and by detecting the change in the resonant frequency, the above-mentioned applied voltage (2) can be determined.

【Example】

Next, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a cylindrical gas tank 1 is filled with gas having a large dielectric strength, and a cylindrical high voltage terminal 2 is concentrically arranged in the center thereof. A housing 3 for holding electrodes is attached to the side wall of the gas tank 1. In this housing 3, a movable electrode plate 4 is movably held by a suitable elastic holding member, such as the bellows 6 shown. A fixed electrode plate 5 is fixed by a terminal bar 7 so as to face the movable electrode plate 4. This terminal bar 7 is attached to the rear part of the housing 3 via an insulating plate 8. As described above, the movable electrode plate 4 is held by the bellows 6 so as to be movable in the horizontal direction in the figure, that is, in the direction toward and away from the high voltage terminal 2 located at the center of the gas tank 1. It is maintained at the same potential as the side wall of the gas tank 1 via the housing 3. Therefore, the movable electrode plate 4 receives electrostatic attraction force due to the high voltage applied to the high voltage terminal 2 and moves in the above direction. Assume now that the movable electrode plate 4 is in the same position as the side wall of the gas tank 1. The electrostatic attractive force F acting between the side wall of the gas tank 1 and the high voltage terminal 2 is expressed as follows: If the outer diameter of the high voltage terminal 2 is rl and the inner diameter of the gas tank l is rl, then the distance t between them is t=r2-rl. , and if the voltage between these is V, the electric field strength E is
When t<rl, rl, it is a good approximation and E=V/l, so F=(εoE2)/2 = (t oV2) / (2t '') [N/m2
1, and this force F acts on the movable electrode plate 4 and tries to move it. That is, with this force F, the movable electrode plate 4
is attracted towards the two high voltage terminals. As a result, the capacitance C formed between the movable electrode plate 4 and the fixed electrode plate 5 decreases. This capacitance JiC forms a resonant circuit 9, and the resonant frequency changes as C decreases. For example, when forming an LC resonant circuit, its resonant frequency f is f=1/(2πrrτ), so between the change ΔC in C and the change Δf in f, Δf/f=<-172> (ΔC/C) holds true. Further, if the distance between the electrode plates 4.5 is b and the effective area of the electrode plates 4.5 is S, then C=εs/b ΔC=−(εs/b2)Δb. Therefore, from these equations, ΔfccΔCocFccV2 is established, and from this it can be seen that the high voltage ■ can be measured from fτ. Therefore, in this embodiment, the high voltage is measured by detecting the change in the resonant frequency f of the resonant circuit 9 using the frequency detection circuit 10, as shown in FIG. Note that this frequency detection circuit 10 may be, for example, a frequency detection circuit. In this way, since the electrostatic attraction force F, which is proportional to the square of the high voltage ■, is taken as a change in the capacitance C, highly accurate voltage measurement is possible without the need for a particularly precise resistor. . Furthermore, by increasing the Q (sharpness) of the resonant circuit 9, changes in the resonant frequency f can be detected more acutely.

【Effect of the invention】

According to the high voltage measuring device of the present invention, it has a very simple configuration and has few moving parts, so maintenance is easy and does not take up much installation space, and high voltage can be measured with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention. 1... Gas tank, 2... High voltage terminal, 3...
... Electrode holding housing, 4... Movable electrode plate 1.5
... Fixed electrode plate, 6... Bellows, 7... Terminal bar, 8... Insulating plate, 9... Resonance circuit, 10... Frequency detection circuit.

Claims (1)

[Claims] (1) A movable electrode plate held so as to be moved by electrostatic attraction from a portion to which a high voltage is applied, a fixed electrode plate held so as to face the movable electrode plate, and this movable electrode A high voltage measurement device comprising: a resonant circuit including a capacitance formed between a plate and a fixed electrode plate; and a circuit for detecting a change in the resonant frequency of the resonant circuit.