What s going on with the power frequency withstand voltage test?

1) Check the test wiring to ensure that it is correct, the tested transformer shell and non-pressurized winding should be reliably grounded, the gas protection should be put in, and the overcurrent and overvoltage protection in the test circuit should be set correctly and reliably.

2) When the AC withstand voltage test is carried out on the transformer, it must be carried out only after the insulating oil is in a stationary state and the bubbles have fully escaped. Otherwise, it will cause discharge during the withstand voltage test, which will make it difficult to judge. 3. The transformer oil of 10kV needs to be static for more than 5h, and the transformer oil of 110kv and below is stationary for 24h; 220kv transformer oil static for 48h; The 500kv transformer oil is stationary for 72h to avoid undue insulation breakdown caused by withstand voltage.

3) All parts that can be vented, such as the bushing and holes of the oil-immersed power transformer, should be fully vented to avoid the reduction of dielectric strength due to residual air, resulting in breakdown or discharge.

4) in the course of the test; The boost speed should be uniform When the voltage rises above 40 test voltage, it should keep 3 test voltage rise per second; The step-down should be rapid, but avoid abruptly cutting off the power supply above the 40 test voltage.

5) The AC power frequency withstand voltage test of the three-phase transformer does not have to be carried out in phase, but the three-phase lead wire end of the winding on the same side must be short-circuited before the test, otherwise the insulation of the transformer winding may be damaged.

6) The AC withstand voltage time is 1 min. In the event of a discharge or breakdown, the voltage should be immediately reduced and the power supply should be cut off.

7) During the pressurization period, pay close attention to the indication dynamics of the meter, observe and monitor the tested transformer, protect the sound and phenomenon of the ball gap, and analyze the relevant signs such as corona or discharge.

By: Sanxin Power

The power frequency withstand voltage test is to gradually increase the voltage with 50 Hz alternating current to test the withstand voltage level of the tested components.

Legal analysis: power frequency withstand voltage test device It is the basic test equipment for power stations, power supply and distribution systems and scientific research units, etc., which is used to test the dielectric strength of various electrical products, electrical components, insulating materials, etc. under the specified voltage, assess the insulation level of the product, find the insulation defects of the tested product, and measure the ability of overvoltage. Power frequency withstand voltage test of 6kv-500kv transformer.

Legal basis: Article 2 of the Standardization Law of the People's Republic of China The standards (including standard samples) mentioned in this law refer to the technical requirements that need to be unified in the fields of agriculture, industry, service industry and social undertakings. Standards include national standards, industry standards, local standards, group standards, and enterprise standards.

National standards are divided into mandatory standards and recommended standards, and industry standards and local standards are recommended standards. Mandatory standards must be enforced. The State encourages the adoption of recommended standards.

1. When conducting experiments, there should be checkers for operators in the control room; The test hall has the person in charge of the test and the guardians. The whole experimental process of the sample should be carried out under the unified command of the person in charge of the test. Anyone has the right to question the person in charge of the insecurity and refuse to enforce it.

2. Before the experiment, check whether the test transformer and related supporting equipment are in good condition and the grounding system is correct. Close the doors of the test hall, and irrelevant personnel are not allowed to enter.

3. Adjust the ball gap distance of the overvoltage protection device to meet the overvoltage protection requirements of the tested product, and verify its accuracy through no load.

4. Put the test sample on the sample rack, connect the ground wire and high-voltage lead, and confirm that it is correct, the test personnel leave the site, the test person in charge and the guardian leave the test area, and use the operation command or gesture to notify the operator that the operation can be carried out.

5. The operator checks that the switch of the control equipment should be in the disconnected position, and the position of the voltage regulator should be at the zero position, and after the checker is correct, the test hall personnel will be notified to "start the test", and the operation can only be carried out after hearing the obvious indication of the hall personnel.

6. The operator and the checker must stand on the insulated table mat, close the power switch and control switch, and the indicator light on the console should be on.

7. Start the high-voltage closing button, the red light of the indicator light of the console and the test hall should be on, and then press the boost button to slowly boost the voltage.

8. Carry out power frequency withstand voltage test on the product according to the experimental data specified in the product regulations. The test transformer shall not be overvoltage, and the continuous work shall not exceed half an hour.

9. If there is an abnormal phenomenon in the control room during the product test process, the operator and the checker shall stop the test according to the specific situation and notify the person in charge of the test. If there is any abnormality in the test hall, the person in charge of the test and the guardian shall notify the operator to stop the test.

10. After the product test is completed, all switches should be stopped, and the operator and checker should leave the control room, and the high-voltage part of the equipment can be disassembled and assembled after confirming that there is no electricity.

11. In the whole power frequency withstand voltage process, it is strictly forbidden for all personnel to walk around and make loud noises in the hall.

12. After the work is completed, the power must be turned off, the equipment and on-site sanitation must be cleaned up, and the equipment operation record and test record must be filled.

The power frequency withstand voltage test is to use the power frequency high voltage that exceeds a certain multiple of the rated voltage of the tested product to replace the internal overvoltage that the equipment can withstand during the actual operation, and test the insulation of the tested product for a certain time (usually 1 minute) according to the regulations. He can effectively detect the concentrated defects in the insulation, and assess the insulation level of the equipment.

As mentioned above, the insulation withstand voltage level of electrical equipment is determined according to the comprehensive comparison of the internal and external overvoltage values of the system. For equipment of 220 kV and below, it is not economical to limit the atmospheric overvoltage to a level lower than the internal overvoltage. Therefore, the test voltage should be mainly based on the internal overvoltage, and the role of external overvoltage and long-term working voltage should also be considered.

Power frequency withstand voltage test device It is the basic test equipment for power stations, power supply and distribution systems and scientific research units, etc., which is used to test the dielectric strength of various electrical products, electrical components, insulating materials, etc. under the specified voltage, assess the insulation level of the product, find the insulation defects of the tested product, and measure the ability of overvoltage.

Classification: KV-500KV High Voltage Cross-Linked Cable.

AC withstand voltage test.

2. Generator.

AC withstand voltage test.

3. GIS and SF6 switches.

AC withstand voltage test.

KV-500KV transformer.

Power frequency withstand voltage test.

5. AC withstand voltage test of other power high-voltage equipment such as busbar, casing and transformer.

The power frequency AC withstand voltage test is to apply a certain voltage to the tested product and hold it for a certain time to consider the ability of the tested product insulation to withstand various voltages, so as to ensure the safe operation of the equipment.

Although many insulation defects can be found in the insulation resistance and absorption ratio test, leakage current and DC withstand voltage test and dielectric loss angle measurement test, the test voltage of the gene is lower than the working voltage of the tested product, and some insulation defects can not be found in time, in order to further expose the equipment defects, check the insulation level of electrical equipment and ensure whether it can be put into operation, it is necessary to carry out AC withstand voltage test. It is the most effective and direct method to identify the dielectric strength of electrical equipment, and it is of decisive significance for judging whether electrical equipment can be put into operation.

The voltage, waveform, frequency and distribution of voltage inside the insulation of the tested product are in line with the actual operating conditions, so the AC withstand voltage can effectively find the more dangerous concentrated defects in electrical equipment. The higher the test voltage, the higher the effectiveness of the insulation defect found, but the greater the possibility of the test product being broken down.

For samples with good insulation, the AC withstand voltage will gradually weaken the dielectric strength, forming an accumulation effect of inferior quality inside the insulation. The value of insulation breakdown voltage is not only related to the applied voltage, but also related to the duration of pressurization, and its breakdown voltage gradually decreases with the increase of pressurization time. Therefore, it is necessary to correctly select the standard of the test voltage and the withstand voltage time.

The power frequency withstand voltage test device is used to test the insulation strength of various electrical products, electrical equipment, insulating materials, etc. under the specified voltage, assess the insulation level of the product, find the insulation defects of the tested product, and measure the ability to withstand overvoltage. It is the equipment of power supply enterprises, large factories, metallurgy, power plants, railways and other power maintenance departments. It is widely used in electrical manufacturing departments, power operation departments, scientific research units and colleges and universities.

Power Frequency Withstand Voltage Test Device Power frequency withstand voltage test equipment designed according to the latest national power industry standards. It is the rigorous, most straightforward method for identifying the dielectric strength of electrical equipment. It can check out which dangerous concentrated defects, to judge whether the power equipment can continue to participate in the operation has a decisive role, is to ensure the level of equipment insulation, to avoid insulation accidents of an important means.

It is used to conduct dielectric strength tests under specified voltages for various electrical products, electrical components, insulating materials, etc., to assess the insulation level of products, find insulation defects of tested products, and measure the ability of overvoltage.

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The power frequency withstand voltage tester adopts the withstand voltage of the series resonance withstand voltage test device (also known as the variable frequency series resonance device or series resonance withstand voltage test equipment), which is the latest generation of AC withstand voltage test equipment especially suitable for large-capacity capacitive test products (such as generators, cables, etc.). Very convenient for on-site use.

In the operation of power equipment, the insulation will gradually deteriorate under the action of electric field, temperature and mechanical vibration for a long time, including overall deterioration and partial deterioration, forming defects. Power frequency AC withstand voltage test is the most effective and direct method to identify the dielectric strength of power equipment, and it is an important part of preventive test. In addition, because the AC withstand voltage test voltage is generally higher than the operating voltage, so after passing the test, the equipment has a large safety margin, so the AC withstand voltage test is an important means to ensure the safe operation of power equipment.

Power frequency withstand voltage.

The test is to carry out DAO regulations for various electrical products, electrical components, ZHI insulation materials, etc.

The insulation strength test under pressure is used to assess the insulation level of the product, find the insulation defects of the tested product, and measure the ability of overvoltage.

Wugao Electric Measurement WDYD intelligent power frequency withstand voltage test device adopts advanced microcomputer technology that keeps pace with the times, digital measurement and control means combining software and hardware, and its sophisticated design and thoughtful and meticulous consideration implement the design concept of "all for the sake of users", so that you can use it easily and handy.

Full keyboard operation, full digital measurement and control, intelligent work process;

Four display windows simultaneously display high and low voltage voltage, current and withstand voltage time, as well as multiple status indicators;

High-precision measurement and data processing, display accuracy can be better;

Keyed automatic, manual working mode;

Automatic motor inertia judgment and compensation, approximate voltage regulation algorithm;

Automatically capture the peak voltage and current, which is convenient for breakdown test;

Arbitrarily set high-voltage voltage, high-voltage current, low-voltage current and withstand voltage time;

After reaching the set voltage, the automatic withstand voltage timer, the timing time will automatically step down to zero;

When the set current (any of the high and low voltage currents) is exceeded, the voltage output will be automatically cut off, the voltage will be automatically lowered back to zero, and an audible and visual alarm will be issued.

The test results can be viewed and printed, and have an automatic manual printing mode;

The sound of music is different, and the sound is different in different states;

Software and hardware anti-interference design, strong anti-interference ability;

Automatic error diagnosis for easy detection and problem solving.

Any incoming test product should be subjected to other insulation tests before the AC withstand self-pressure test, and then the withstand voltage should be carried out after it is qualified.

Trial. Insulation resistance should usually be measured before and after the hipot test. In addition, if the oil-filled equipment is filtered or transported, the test should be allowed to stand for a period of time before the pressure test to eliminate the air that may remain inside.

Connect the test product, turn on the power supply, and start the step-up test. During the boosting process, the high-voltage circuit should be closely monitored to listen for any abnormal sound of the test product. Rise to the test voltage and start the timer.

When the time is up, step down and then cut off the power. If there is no destructive discharge in the test, it is considered to have passed the withstand voltage test.

This series of control boxes.

The copy is composed of a contact voltage regulator and its control, protection, measurement and signal circuits. It is by connecting to the power frequency power supply and adjusting the voltage regulator (i.e., the input voltage of the test transformer) to obtain the required test high voltage value. The working principle is shown in Figure 1

Figure 1The working principle of GDYD-M series control box.

5. Description of panel structure.