1. Dust control
Foreign objects and dust are very important factors in causing partial discharge. The test results show that metal particles with a diameter of ф 1.5 μ m can generate discharges far greater than 500pC under the action of an electric field. Both metal and non-metal powders generate a concentrated electric field, which lowers the initial discharge voltage and breakdown voltage of the insulator. Therefore, it is very important to maintain environmental and body cleanliness during the manufacturing process of transformers, and strict control of dust must be implemented. Strictly control the extent to which products are affected by dust during the production process and establish sealed and dust-proof workshops.
2. Centralized processing of insulation components
It contains metal dust, which is very important because once the insulation sheet adheres to the metal dust, it is difficult to completely remove it. Therefore, it is necessary to handle it centrally in the isolation workshop and set up an area that must be isolated from other dust producing areas.
3. Strictly control the machining burrs of silicon steel plates!
The transformer core components are formed by longitudinal and transverse cutting. These cutting cuts have varying degrees of burrs. Burrs not only cause short circuits between chips, but also increase losses and the thickness of the iron core. More importantly, when the iron core is inserted into the magnetic yoke or subjected to vibration during operation, burrs may fall onto the body and discharge may occur. Even if burrs fall to the bottom of the box, they can be arranged in an orderly manner under the influence of an electric field, causing ground potential discharge. Therefore, the burrs on the core should be as small as possible. The burrs on the core part of 110KV products should not exceed 0.03mm
4. Lead wire, cold pressed terminal
The use of lead cold pressed terminals is an effective measure to reduce partial discharge. When using phosphor copper welding, a large amount of spatter welding slag will be formed, which is easy to spread to the body and insulation parts. In addition, the source boundary area must be separated by submerged asbestos wires so that water can enter the insulation layer. If the moisture in the insulated winding is not completely removed, it will increase the partial discharge of the transformer.
5. Edge of rounded corner component
The purpose of rounding the edge of the component is to improve the field power distribution and increase the discharge starting voltage. Therefore, metal structural components such as clips, pull plates, pads and support edges, pressure plates and outlet edges, walls of the box riser, and magnetic shielding covers on the inside of the box wall in the iron core must be rounded. Prevent friction from producing iron filings. For example, the contact part between the hanging hole of the clamp and the hanging rope or hook should be circular.
6. Product environment and body coating during the final assembly process
After vacuum drying, the hull should be classified before packaging. The larger the product, the more complex the structure, and the longer the completion time. When the valve stem is compressed and tightened, it is exposed to air, during which moisture absorption and dust dispersion occur. Therefore, the vehicle body should be cleaned in dust-proof areas such as when completed (or exposed to the air). If the time exceeds 8 hours, it must be dried again. After the completion of the hull, the vacuum pumping and fuel tank filling phase begins. Due to the fact that the stem insulation material absorbs moisture during the stem trimming stage, it is necessary to dehumidify the stem. This is an important measure to ensure the insulation strength of high-voltage products. The method of use is to evacuate the product. Determine the vacuuming time based on the body
7. Vacuum lubrication
The purpose of vacuum oil injection is to inject transformer oil into the vacuum, eliminate dead corners in the insulation structure of the product by vacuuming the transformer, completely evacuate the air, and then completely absorb the transformer body. After oil injection, wait for at least 72 hours before testing the transformer, as the degree of penetration of the insulation material is related to the thickness of the insulation material, the temperature of the insulation oil, and the immersion time. The higher the degree of penetration, the less likely ejaculation is, so please ensure that sufficient absorption time has passed.
8. Sealing of fuel tanks and components
The quality of the sealing structure is directly related to the leakage of the transformer. If there is a leakage point, moisture will inevitably enter the interior of the transformer, causing the transformer oil and other insulation components to absorb moisture, which is one of the factors of partial discharge. Therefore, it must meet reasonable sealing values.
The ZC-254 four channel partial discharge detector is suitable for AC and DC partial discharge detection and positioning of transformers, reactors, generators, transformers, bushings, GIS, lightning arresters, high-voltage switches, switchgear, and other high-voltage electrical equipment. Widely used in high-voltage electrical equipment manufacturers, power electronics high-tech enterprises, power supply companies across the country, and power science research institutes and other units.
Kvtester Electronics Technology Co.,Ltd. is a high-tech enterprise specializing in power testing, testing, research and development, production, and sales of testing equipment. It has been engaged in the electrical testing industry for many years, and its products are of high quality. We welcome customers to come and purchase. Service hotline: 0086-27-81778799, to learn more, visit the official website: www.kvtester.com
