JP2002328148A - Method of measuring insulation characteristic at high temperature for insulation gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a convenient method for obtaining an insulation characteristic of insulation gas at a high temperature to allow equipment design based on a quantitative relation between the temperature and the insulation characteristic. SOLUTION: Plasma simulated with a high temperature gas condition is generated by a laser, a relation between a lapse time after the plasma is generated and a temperature is obtained, a change of dielectric strength accompanied to a change of the temperature of the generated plasma is obtained based on the lapse time after the plasma is generated and a change of the dielectric strength of the plasma, and the insulation characteristics, of the measuring- objective insulation gas, at a specified temperature is applied to the change of the dielectric strength accompanied to the change of the temperature of the generated plasma, so as to obtain the dielectric strength of the measuring- objective insulation gas at the high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for the evaluation of insulating properties in high-temperature insulating gas such as SF ₆ gas during arc interruption in the gas circuit breaker.

[0002]

2. Description of the Related Art SF ₆ gas is widely used as an insulating medium stop gas for gas insulated switchgear (GIS), gas insulated transmission line (GIL), etc. because of its excellent insulating properties and arc extinguishing performance. . Further, since SF ₆ gas is a greenhouse gas, it constitutes a main component of the atmosphere, and the use of a mixed gas with N ₂ gas which is basically unrelated to global warming is being studied.

[0003] When a short circuit occurs in a gas-insulated power device using such an insulating gas, a large current flows and the insulating gas is heated to a high temperature. When the gas insulated switch (circuit breaker) is opened, the insulating gas is heated by the generation of an arc. In such a high temperature state, the insulating gas is in a plasma state, and the conductivity increases. That is, the dielectric strength is "decreased", resulting in dielectric breakdown failure of the device. For this reason, it is necessary to take into account the insulating properties of such an insulating gas in a high temperature state when designing the equipment.

However, in the conventional device design, a method based on a try-and-error method has been adopted in which a mock-up model is created according to an empirical rule, and a current cutoff test is actually performed to check whether insulation breakdown occurs.

However, in such a design method based on trial and error, it is not possible to obtain the relationship between the dielectric strength of insulating gas and the temperature which is versatile in the obtained data.
Further, there is a problem that not only costs and time are required for manufacturing the mock-up model, but also that the reliability of the manufactured device is lacking.

[0006]

The problem to be solved by the present invention is to provide a simple method for knowing the insulating characteristics of an insulating gas at a high temperature, and to obtain a device based on a quantitative relationship between the temperature and the insulating characteristics. It is to enable design.

[0007]

SUMMARY OF THE INVENTION The present invention provides a method for measuring the insulating properties of an insulating gas at a high temperature. The method includes the steps of generating a plasma simulating a high-temperature gas state with a laser, knowing the relationship between the elapsed time after the plasma generation and the temperature, From the elapsed time after the plasma generation and the change in the dielectric strength of the plasma, the change in the dielectric strength with the change in the temperature of the generated plasma is known, and the insulation characteristics at a specific temperature of the insulating gas to be measured are measured. By applying the change in the dielectric strength accompanying the measurement, the dielectric strength at a high temperature of the insulating gas to be measured is known.

According to the present invention, a plasma can be generated with high reproducibility by using a laser, and plasma generation and voltage application can be accurately controlled by an electronic circuit, so that a high temperature state of an insulating gas can be simulated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a procedure for measuring characteristics of a generated plasma for simulating the high-temperature insulating characteristics of an insulating gas to be measured by simulating a high-temperature state of SF ₆ gas as an insulating gas. Is shown.

FIG. 1A shows an apparatus for generating a plasma for simulation by laser irradiation. As shown in the figure, a laser beam of a YAG laser was condensed on SF ₆ gas, and the gas in that portion was ionized to form a plasma having the characteristics of a high-temperature gas such as when an arc was generated.

On the other hand, a decrease in the temperature of the plasma generated by the apparatus shown in FIG. 1A with time was measured by an interferometer method using the apparatus shown in FIG. 1B. In the apparatus shown in FIG. 1B, the electron density and the neutral gas density in the plasma are obtained based on a two-wavelength interferometer method using two laser beams (L1 and L2 in the figure) having different wavelengths. The temperature is derived from the obtained values. By performing such a measurement while changing the time after plasma generation, the relationship between the passage of time and the temperature drop can be obtained. FIG.
FIG. 2 is a diagram showing a relationship between a time lapse and a temperature after generation of generated plasma obtained by the apparatus shown in FIG.

With respect to the plasma generated by the apparatus shown in FIG. 1A, the change of the insulation characteristics with time was measured by the apparatus shown in FIG. In this measurement, an impulse voltage is applied at a certain timing after plasma generation. At that time, the voltage value at which the dielectric breakdown occurs is obtained by changing the peak value of the applied voltage, whereby the dielectric breakdown voltage at that timing is determined. By performing this measurement method while changing the timing of voltage application, a change in insulation characteristics over time can be obtained. This measurement was performed by delaying the voltage application timing for measuring the insulation characteristics. FIG. 4 is a diagram showing the relationship between the time elapsed after plasma generation and the insulation characteristics obtained by the apparatus of FIG.

FIG. 5 shows the relationship between the time and temperature of the simulation plasma shown in FIG. 3 and the relationship between the temperature and the insulation characteristics obtained from the relationship between the time and the insulation characteristics shown in FIG. 4 (conceptual diagram). Is shown.

By applying the insulation characteristics at a certain temperature of the insulation gas to be actually measured from the relationship shown in FIG. 5, the relationship between the insulation characteristics of the insulation gas and the temperature can be known.

[0015]

According to the present invention, the relationship between the temperature of the insulating gas and the insulating characteristics can be relatively easily and accurately determined regardless of the type of gas.

Also, according to the present invention, SF₆Repel gas
SF that will be developed in the future₆ High temperature of alternative gas
The insulation characteristics of the
Excellent various gas insulation equipment can be designed. Therefore,
Insulation against transient recovery voltage when circuit breaker is opened (arc interruption)
Edge design support, insulation characteristics evaluation of new insulating medium gas at high temperature
(At the time of interruption / short circuit accident).

[0017]

[Brief description of the drawings]

[0018]

FIG. 1 shows a laser generator for simulating the high-temperature insulation properties of an insulating gas to be measured in a plasma, simulating a high-temperature state of SF ₆ gas as an insulating gas. FIG. 2B shows a procedure for measuring the relationship between the time elapsed after plasma generation and the plasma temperature.

[0019]

FIG. 2 shows how to measure the relationship between the time elapsed after plasma generation and the insulating properties of plasma.

[0020]

FIG. 3 shows a relationship between a lapse of time and a temperature after generation of generated plasma obtained in the manner of FIG. 1B.

[0021]

FIG. 4 shows the relationship between the time lapse after the generation of the generated plasma obtained in the manner of FIG. 2 and the insulation property.

[0022]

FIG. 5 shows a relationship (conceptual diagram) between the temperature and the insulation characteristics obtained from FIGS. 3 and 4.

[0023]

[Explanation of symbols]

 L1, L2: laser light

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H02B 13/055 H02B 13/06 J5G365 H02G 5/06 391 (72) Inventor Moo Zha Senshu, Tobata-ku, Kitakyushu-shi, Fukuoka 1-1, Kyushu Institute of Technology, Kyushu Institute of Technology No. 1-47 F-term in Kyushu Electric Power Co., Inc. Research Laboratory (Reference)

Claims (2)

[Claims] 1. A plasma simulating a high-temperature gas state is generated by a laser, a relationship between an elapsed time after the plasma is generated and a temperature is measured, and a change in an elapsed time after the plasma is generated and a change in a dielectric strength of the plasma are measured. From the relationship between the elapsed time and temperature after the generation of the plasma and the change in the dielectric strength of the plasma from the elapsed time after the generation of the plasma and the change in the dielectric strength of the plasma, the change in the dielectric strength with the change in the temperature of the generated plasma is known. A method for measuring the insulation properties at a high temperature of an insulating gas, wherein the insulation properties at a specific temperature are applied to the change in the dielectric strength attributable to the change in the temperature of the generated plasma to determine the insulation strength at a high temperature of the insulation gas to be measured. 2. The insulation characteristics of an insulating gas at a high temperature according to claim 1, wherein the elapsed time after the generation of the plasma and the change in the dielectric strength of the plasma are changed by shifting the timing of the voltage application time for measuring the dielectric strength. Measuring method.