JPS582623B2 - Partial discharge quantity detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating and measuring various quantities of partial discharge in electrical insulators, a composite electrode for detection thereof, and a detection device used in combination with the composite electrode device. The object of the present invention is to provide a detection device that can independently measure various amounts of partial discharges generated in different air gaps between an electrode and an electrical insulator.

Conventionally, in partial discharge deterioration tests of electrical insulators, needle-shaped, rod-shaped, spherical, etc. electrodes are used as the upper electrode, and flat electrodes are used as the lower electrode, and high voltage is applied to the upper and lower electrodes. Various amounts of partial discharge are measured using a detection circuit connected in series between the electrodes.

However, since the lower electrode is a continuous flat plate, the measured values of various amounts of partial discharge can only be obtained in correlation with the total amount of partial discharge that occurs on the surface or inside the electrical insulator.
In particular, it is impossible to separate and measure only the partial discharge near the breakdown point of electrical insulation, and various quantities such as the amount of partial discharge and discharge waveform at that point can be estimated from the correlation coefficient value of the total amount of partial discharge. However, it has the disadvantage that such estimation is extremely difficult.

Note that there is also a method such as Japanese Patent Publication No. 46-2308, which measures the non-uniformity of resistance within a characteristic element. Since there is no air gap between the characteristic elements of the object and the electrode, there is no structure in which partial discharge occurs.

Therefore, it has certain drawbacks, such as not being able to be used for the purpose of measuring various amounts of partial discharge generated in the air gap above the test object.

However, in the present invention, the lower electrode is a composite electrode in which electrodes are arranged concentrically, and each electrode part can independently measure various amounts of partial discharge. It enables the creepage measurement of various discharge quantities such as discharge amount and discharge waveform of adjacent parts, and is an excellent method for determining whether an electrical insulator is an industrially effective insulator. It has a certain effect.

Reference will now be made in detail to the accompanying drawings, which illustrate embodiments of the invention.

1 is a needle-shaped L part electrode that is usually used, 2, 3
, 4, 5 and 6 are composite lower electrodes corresponding to conventional flat plate electrodes. The electrodes 2 are arranged concentrically with electrode holding insulating plates 8 interposed between and around the outer periphery of the electrodes 2 in the horizontal direction, and constitute the electrode section a.

That is, the composite electrode according to the present invention is characterized by being composed of a plurality of electrodes.

7 is an electrical insulator which is a test sample, and the needle-shaped upper electrode 1
The concentric lower electrode 2 is not in contact with or is in partial contact with the concentric lower electrode 2.
, 3, 4, 5, and 6.

2', 3', 4', 5' and 6' are pulse transformers connected to the lower surfaces of the composite lower electrodes 2, 3, 4, 5.6 and their input terminals, respectively. ',4
The other input terminals of ', 5', and 6' are connected to the upper electrode 1 through a power supply part b, which is made up of a high voltage generator 9 and a coupling capacitor 15 connected in parallel, and the partial discharge components are transferred to the power supply part b. It is detected separately from the current component, and is used as an element for detecting various quantities of partial discharge.

10, 11, 12, 13 and 14 are the output terminals of the pulse transformers 2', 3', 4', 5' and 6', respectively, and are compatible with currently commercially available partial discharge quantity measuring devices such as voltmeters and oscilloscopes. It connects pulse transformers 2', 3',
4', 5', and 6' are used as detection parts C for detecting various amounts of partial discharge from the lower electrodes 2, 3, 4, 5, and 6 separately for each electrode.

These detection pulse transformers 2', 3', 4', 5'
The input impedances of 6' and 6' are all the same value, which is very small compared to the impedance between each electrode of the composite electrode (for example, between electrode 2 and electrode 3), and each detection pulse transformer Since the electrodes are grounded in common, the various quantities of partial discharge of each electrode can be measured without being affected by each other.

Furthermore, by using a detection part C that can easily convert the input impedance on the input side and the output impedance on the output side like a pulse transformer, a part of the output of the detection part C (for example, through the electrode 2 and the detection pulse transformer 2' It is characterized in that it is not affected by the detection impedance between the electrodes on the input side of the detection section even if a partial discharge quantity measuring device is connected to the detected partial discharge output (output of the detected partial discharge).

16 is a broken line indicating the generation path of partial discharge in the air gap, and the partial discharge is generated radially in the horizontal direction from near the tip of the needle electrode 1.

For example, suppose that a partial discharge deterioration test is performed by placing an electrical insulator between a conventional needle-like electrode and a flat plate-like electrode and applying a high voltage.

In this case, it is known that the breakdown point of the electrical insulator is near the vertical bottom of the needle electrode.

When a similar partial discharge deterioration test is conducted in the circuit shown in FIG. 3 as in the present invention by placing an electrical insulator between the needle electrode 1 and the composite electrodes 2, 3, 4, 5, and 6, the breakdown location is near the upper surface of the electrode 2 which is vertically below the needle electrode 1.

Therefore, from the various amounts of partial discharge detected at the electrode 2, only the various amounts of partial discharge that are considered to be directly caused by the breakdown can be measured.

As is clear from the above explanation, it is possible to detect various amounts of partial discharges that can accurately determine only the deterioration process of electrical insulators due to partial discharges, which is extremely effective in practical use.

In addition, when implementing the present invention, the implementation conditions are Frequency: 5KHz, Gap: O (mm) Sample: PET Test atmosphere: two atmospheres Applied voltage: 3, 4, 5KV The test results are shown in Figure 4.

[Brief explanation of the drawing]

The accompanying drawings show embodiments of the present invention, in which Fig. 1 is a side sectional view, Fig. 2 is a plan view of a concentric lower electrode, Fig. 3 is an explanatory diagram of a method for detecting various quantities of partial discharge, and Fig. FIG. 4 shows the results of measuring partial discharge pulses using the circuit shown in FIG. 3. 1... needle-like upper electrode, 2, 3, 4, 5, 6...
...Composite lower electrode, 2', 3', 4', 5', 6'
...Pulse transformer for detecting various quantities of partial discharge, 7
...Electric insulator, 8... Electrode holding insulating plate, 9... High voltage generator, 10, 11, 12
, 13, 14... Output terminal, 10, 11, 12
, 13, 14... Output terminal, 15...
Coupling capacitor, 16... Partial discharge generation path in the air gap.

Claims (1)

[Claims] 1. When measuring various amounts of partial discharge in electrical insulators, a needle-shaped, spherical, rod-shaped, etc. electrode is provided as the upper electrode, and an electrode holding insulating plate is interposed on the outer periphery and between the electrodes at a position facing the upper electrode. At least a composite lower electrode arranged concentrically is provided,
One input terminal of a pulse transformer is connected to each of the composite electrodes, the other input terminal of the pulse transformer and the upper electrode are connected via a power supply section, and an electrical insulator serving as a test sample is placed on the composite lower electrode. A device for detecting various amounts of partial discharge, characterized in that a known partial discharge amount measuring device is connected to the output terminal of the pulse transformer.