JPH08122385A - Space charge measuring apparatus - Google Patents

Abstract

PURPOSE: To obtain a space charge measuring apparatus for measuring the space charge of a sample under high temperature. CONSTITUTION: The space charge measuring apparatus comprises a tubular cell 1 made of a heat resistant resin being fixed to the upper surface side of a sample S, and one electrode 2 being set on the sample S in the tubular cell 1. The space charge measuring apparatus further comprises the other electrode 3 being set on the sample S on the opposite side to the one electrode 2, a piezoelectric element 4 fixed to the other electrode 3, an insulation oil 5 filled in the tubular cell 1, and a heating means 6 disposed on the outer circumference of the tubular cell 1. The sample S can be heated up to a predetermined temperature by the heating means 6 disposed on the outer circumference of the tubular cell 1 and the space charge of the sample S can be measured under the high temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a space charge measuring device capable of measuring the space charge of a sample to be measured at high temperature.

[0002]

2. Description of the Related Art Conventionally, polyethylene sheet (film)
In many cases, the space charge in an insulator such as the above is usually measured at room temperature (room temperature = about 25 ° C.).

[0003]

However, insulation sheets such as polyethylene sheets used for electric wires and cables can be used not only at room temperature but also at high temperatures (above room temperature to about 120 ° C.). There are times when I want to know if such a space charge can be obtained. For example,
This is because it becomes possible to more accurately grasp the behavior of the space charge at high temperature of the polyethylene sheet that is the insulating material of the laid electric wire.

In such a case, in the conventional measuring device, since the measurement is usually performed at room temperature as described above, it is structurally impossible to cope with the measurement at high temperature.
Particularly, in the conventional measuring device, since the cylindrical cell attached to the upper surface side of the sample to be measured is made of acrylic resin or the like, it cannot withstand high temperature, and an appropriate heating means for heating the sample to be measured. There was no such thing.

The present invention has been made in view of such a conventional situation, and the sample to be measured is heated to make a predetermined high temperature state, and the space charge under this is measured. It is intended to provide a space charge measuring device.

[0006]

The features of the present invention are that a cylindrical cell made of a heat-resistant resin attached to the upper surface side of a sample to be measured and the sample to be measured in the cylindrical cell. One electrode installed on the other side, the other electrode installed on the opposite side of the one electrode of the sample to be measured, the piezoelectric element attached to the other electrode, and filled in the tubular cell. One electrode, which consists of insulating oil and heating means provided on the outer periphery of the cylindrical cell, or, if necessary, one of the electrodes installed in the cylindrical cell has a disc-shaped main body, and the disc-shaped main body In the space charge measuring device, an electrolytic relaxation portion having a curved surface is provided on the outer circumference of the.

[0007]

In the present invention, the sample to be measured can be heated to a predetermined temperature by the heating means provided on the outer periphery of the cylindrical cell made of heat-resistant resin, and under this high temperature, the sample to be measured can be heated. The space charge of the sample can be measured.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the space charge measuring apparatus according to the present invention. In the figure, reference numeral 1 denotes a heat-resistant resin, such as polycarbonate, which is attached to the upper surface side of the sample S to be measured such as a polyethylene sheet.
A cylindrical cell which is preferably transparent or translucent, 2 is one electrode (in-cell electrode) installed on the sample S to be measured in the cylindrical cell 1, and 3 is the above cell of the sample S to be measured. The other electrode (external electrode) made of a metal plate such as copper, which is installed on the opposite side of the internal electrode 2, 4 is a piezoelectric element attached to the external electrode 3, and 5 is silicon oil filled in the tubular cell 1 or the like. Of the insulating oil, 6 is a heating means provided on the outer periphery of the cylindrical cell 1, preferably a lower part, which is composed of a band heater or a mantle heater, and 7 is a base plate for supporting the piezoelectric element 4.

Further, the in-cell electrode 2 is made of a substantially button-shaped metal conductor, and has a disk-shaped main body 2a at its lower end.
While the protruding portion 2b for connecting the electrode wire is provided, the electrolytic relaxation portion 2 formed of a curved surface (semi-circular surface) is provided on the outer periphery of the disk-shaped main body portion 2a.
c is provided.

In this measuring apparatus, first, the heating means 6 is energized prior to the measurement of the space charge of the sample S to be measured. This energization causes the heating means 6 to generate heat, so that the sample S to be measured itself is gradually heated from around the lower end of the cylindrical cell 1 via the in-cell electrode 2 and the like, and reaches a predetermined temperature (room temperature or higher to 120 ° C.). To the extent). Hmm,
The control of the set temperature is performed by installing a temperature sensor such as a thermocouple around the sample S to be measured.

In this way, when the sample S to be measured reaches a predetermined temperature, a measurement voltage (pulse voltage) is applied to the electrodes 2 and 3. By applying this voltage, the piezoelectric element 4
, A change corresponding to the space charge in the sample S to be measured appears. Therefore, if this change is captured by, for example, an oscilloscope, the state of the space charge in the sample S to be measured at high temperature can be measured. it can.

At the time of this measurement, since the tubular cell 1 is made of a heat resistant resin such as polycarbonate, even if the heating means 6 is driven, the tubular cell 1 is not thermally deformed. Further, since the cylindrical cell 1 is filled with the insulating oil 5, a high creeping voltage can be obtained. Further, the in-cell electrode 2 is made of the above-mentioned button-shaped metal conductor, and the electrolytic relaxation portion 2c is formed on the outer periphery of the disk-shaped body portion 2a at the lower end.
A good discharge preventing function can be obtained by using the one provided with.

By measuring the space charge at such a high temperature, for example, in an insulating sheet such as a polyethylene sheet used for electric wires and cables, the electric wires and cables in a laid state are heated for some reason. In this case, the behavior of the insulating material can be understood more accurately.

[0014]

As is apparent from the above description, according to the space charge measuring apparatus of the present invention, it is possible to measure space charge at high temperature in an insulating sheet such as a polyethylene sheet used for electric wires and cables. It is possible to measure easily and stably. As a result, for example, it is possible to more accurately grasp the behavior of the insulating material in the installed electric wire or cable when it is overheated.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a space charge measuring device according to the present invention.

[Explanation of symbols]

 1 Cylindrical Cell 2 One Electrode (Intra-Cell Electrode) 2a Disk-shaped Main Body 2c Electrolytic Relaxation Part 3 Other Electrode (External Electrode) 4 Piezoelectric Element 5 Insulating Oil 6 Heating Means 7 Base Bed S Measurement Sample (Insulation) Sheet)

Claims (2)

[Claims] 1. A cylindrical cell made of a heat-resistant resin, which is attached to the upper surface side of a sample to be measured, one electrode installed on the sample to be measured in the cylindrical cell, and the sample to be measured. The other electrode placed on the opposite side of the one electrode of the sample, the piezoelectric element attached to the other electrode, the insulating oil filled in the tubular cell, and the outer periphery of the tubular cell were provided. A space charge measuring device comprising a heating means. 2. The one electrode installed in the cylindrical cell has a disc-shaped main body, and an electrolytic relaxation portion having a curved surface is provided on the outer periphery of the disc-shaped main body. 1. The space charge measuring device according to 1.