Voltage breakdown tester for insulator laminated materials

Voltage breakdown tester for insulator laminated materials

The test sample current sensing element should be located at the front end of the step-up transformer. Calibrate the current detection scale according to the test sample current.

6.1.8 The current control response should be carefully set. If the control is set too high, there will be no response when breakdown occurs. If set too low, it will respond to leakage current, capacitor current, or partial discharge current (corona), or respond to magnetization current when the detection element is located at the front end.

6.2 Voltage Measurement - Equipped with a voltmeter to determine the effective value of the test voltage. A voltmeter capable of reading peak values should be used, and dividing the reading by is the effective value. The overall error of the voltage measurement circuit cannot exceed 5% of the measured value. In addition, regardless of the speed used, the hysteresis rate of the voltmeter response time shall not exceed 1% of the entire process.

6.2.1 Measure voltage by connecting a voltmeter or potential transformer to the test sample electrode, or to a separate voltmeter coil on the transformer. The latter connection method will not affect the load of the step-up transformer.

6.2.2 requires the maximum readable voltage of the voltmeter to be greater than the breakdown voltage, in order to accurately read and record the breakdown voltage.

6.3 Electrode - For a given test sample structure, the breakdown voltage will still vary significantly due to the geometric shape and installation position of the test electrode. For this reason, it is important to specify the electrodes used in this testing method and provide an explanation in the report.

6.3.1 The document referring to this testing method provides a detailed explanation of the electrodes listed in Table 1. If there are no specified electrodes, suitable electrodes should be selected from Table 1, or in cases where standard electrodes cannot be used due to the properties or structure of the tested material, other electrodes recognized by both parties should be used. Some examples of special electrodes can be found in Appendix X2. In any case, the electrodes used should be explained in the report.

The entire plane of electrodes 1 to 4 and type 6 in Table 1 should be in contact with the test sample.

6.3.3 The test sample using a Type 7 electrode should be placed inside the electrode during testing, with a distance of no less than 15mm from the edge of the electrode. In most cases, when using a Type 7 electrode for testing, the electrode surface should be in a vertical position. The testing of horizontally placed electrodes cannot be directly compared with the testing of vertically placed electrodes, especially for testing in liquid phase environment media.

6.3.4 Keep the electrode surface clean and smooth, and remove any debris left by previous tests. If the electrode surface is rough, the electrode should be replaced in a timely manner.

6.3.5 It is very important to maintain the specific structure and smoothness of the electrode during the initial production and subsequent surface repair of the electrode. The flatness and surface smoothness of the electrode surface should ensure that the entire area of the electrode can be in close contact with the test sample. When testing very thin materials, surface smoothness will be particularly important, as inappropriate electrode surfaces can cause physical damage to the test material. When repairing the surface, the transition between the electrode surface and a specific edge radius cannot be changed.

6.3.6 Regardless of the difference in size or shape, the electrode located at the stress concentration point, usually the larger one with the largest radius, should have a ground potential.

6.3.7 In some specific liquid-phase metal electrodes, electrode foils, metal balls, water or conductive coated electrodes will be used. It should be recognized that this results in significant differences between the obtained results and those obtained with other types of electrodes.

6.3.8 Due to the influence of electrodes on test results, additional information is often obtained, requiring testing of multiple electrodes to understand the insulation performance of a material (or a group of materials). This is particularly valuable for research testing.

6.4 Environmental media - Documents related to this testing method should specify the environmental media and testing temperature. In order to avoid flashover and minimize the impact of partial discharge before breakdown, even for rapid testing, it is more inclined or even necessary to conduct the test in insulating liquid (see 6.4.1). The breakdown value obtained in insulating liquid cannot be compared with the value obtained in air. The properties of the insulating liquid and the degree of previous use can also affect the test results. In some cases, testing in air requires a large number of test samples or may cause severe surface discharge and erosion before breakdown. Some electrode systems tested in air should be wrapped with pressure pads around the electrodes to prevent flashover. The material of the gasket or seal around the electrode will affect the breakdown voltage value.

6.4.1 If testing is conducted in insulating oil, an appropriately sized oil tank should be provided. (Note - It is not recommended to use glass containers when testing voltages above 10kV, as the energy released by breakdown is sufficient to shatter the container.). And the metal pool must be grounded.

Voltage breakdown tester for insulator laminated materials

1. The experiment is conducted in the test box, and when the door of the test box is opened, the power supply cannot be applied to the input terminal of the high-voltage transformer, that is, there is no voltage on the high-voltage side. The nearest distance between the high-voltage electrode of the 100KV testing equipment and the test box wall is greater than 270mm, and the nearest distance between the high-voltage electrode of the 50KV testing equipment and the test box wall is greater than 250mm. Even if people come into contact with the box wall during the test, there will be no danger.

2. The equipment needs to be equipped with a separate protective grounding wire. Grounding protection is mainly used to reduce the strong electromagnetic interference caused by the breakdown of the sample to the surrounding area. It can also prevent the computer from losing control.

3. The circuit of the experimental equipment is equipped with multiple protection measures, mainly including overcurrent protection, overvoltage protection, leakage protection, short circuit protection, DC test discharge alarm, electromagnetic discharge, etc.

4. DC test discharge alarm function: When the device completes the DC test, the device will automatically alarm when the test door is opened, and the alarm will be automatically cancelled after the discharge device on the device is used for discharge (Note: Failure to discharge electricity after DC testing can pose a danger to human safety, and the electrode cannot be directly taken to remind users to discharge to avoid injury).

5. Experimental discharge device, automatic discharge placement of electromagnet. meet the standard

GB1408.1-2016 "Test Methods for Electrical Strength of Insulation Materials Part *"; Test under Power Frequency, Part 2
GBT13542.1-2009 Thin Films for Electrical Insulation Part *

GB/T1695-2005 "Determination method for power frequency breakdown voltage strength and withstand voltage of vulcanized rubber"
GB/T 3333-1999 "Test Method for Power Frequency Breakdown Voltage of Cable Paper" Scope 1

This part of GB/T 13542 specifies the definition, general requirements, dimensions, inspection rules, marking, packaging, and transportation of thin films for electrical insulation

Transportation and storage.

This section applies to thin films for electrical insulation,

2 Normative References

The clauses in the following documents are referred to as clauses in this section of GB/T 13542. Any citation with a date

All subsequent modification orders (excluding errata) or revised versions are not applicable to this section. However, it is encouraged to reach an agreement based on this section

The parties to the agreement are studying whether the latest versions of these documents can be used. The latest version of any referenced document without a date shall apply to this document

part

GB/T 13542.2-2009 Thin Films for Electrical Insulation Part 2: Test Methods (IEC60674-2:1988, MOD)

3 Terms and definitions

The following terms and definitions apply to this section.

3.1

Windability of winding

The winding performance of the film is used to evaluate the deformation of the rolled film, which can be measured by two aspects: offset/curvature and indentation.

3.1.1

Offset/Arc Bias Camber

When the film is opened flat, its edges do not form a straight line (offset or arc)

3.1.2

depression

sag

When a section of film is supported by two parallel rollers in a horizontal position and subjected to a certain tension, some of the film will be lower than the total

The horizontal plane. Special requirements for joint heat resistance or solvent resistance should be negotiated between the supply and demand parties.

4.4 Tube core

The film should be wound on a circular core, and the core should not shed chips, collapse, or twist under winding tension, nor should it damage the film or reduce its performance

Low. All performance and dimensions of the die, as well as their deviations, shall be negotiated between the supply and demand parties. The preferred inner diameters of the die are 76 mm and 152 mm, and the die can be

Extend the end of the film roll or align it with the end.