How is the testing of transformer oil conducted? The dielectric strength test of transformer oil is conducted using a 500mm³ standard oil cup in a 60kV AC frequency oil tester. The brass electrodes of the oil cup have a diameter of 25mm, and the surface cleanliness is as shown in Figure 92—6, with an electrode
How is the measurement of insulation resistance and absorption ratio conducted? Insulation resistance, denoted as R, is typically determined by applying a voltage of 2500V for 60 seconds and measuring the resulting value using a megohmmeter with a maximum range of 10000 MQ. Due to variations in the stability of insulation resistance arising from differences
How is the measurement of winding resistance conducted? When measuring winding resistance, both the bridge method and voltage drop method are employed. For resistance values exceeding 100, a single-arm bridge is utilized, while for values below 102, a double-arm bridge is employed. In the voltage drop method, a power source consisting of a 2-12V battery
What are the common electrical tests for transformers? Conventional electrical tests for transformers are designed to identify internal faults and primarily include the following: (1) Voltage Ratio Test: Used to verify the voltage ratio and determine if there are short circuits between turns or layers, or if switch leads are connected incorrectly. (2) Winding Resistance
How to conduct a pump test for oil-immersed transformers? Performing a pump test for oil-immersed transformers is an essential step in the production and maintenance processes. For transformers that have completed the assembly, especially those with a capacity of 8000kVA, voltage of 35kV and below, and equipped with an oil storage tank, a pump test
How to perform oil leak repair? To achieve oil welding repair, the following measures can be taken: (1) Selection of Welding Method for Oil Leak Repair： Considering the characteristic of rapid heat dissipation in oil leak repair, arc welding should be used for repairs instead of gas welding. (2) Pre-treatment and Welding Measures for Different
Can transformers be welded with oil for repair? The repair of oil leakage in transformer welding lines is a crucial task for operating personnel. If welding repairs are conducted during a power outage with oil drainage, the transformer body remains inside the oil tank. As the insulation on the transformer body is already impregnated with
Why is it necessary to fill nitrogen and dismantle components such as casings during transportation? And why is it required to remove the oil storage tank and safety duct during vacuum oil injection? When the transport weight of a large transformer exceeds the carrying capacity of the transport vehicle, it is necessary to release the
What are the characteristics of the three commonly used winding configurations in transformers? (1) Y-shaped winding characteristics: The Y-shaped winding has a winding current equal to the line current, with a larger wire cross-section, providing excellent mechanical strength. The winding voltage is equal to 1/√3 times the line voltage, resulting in fewer turns and insulation
What should be noted during the welding of leads for transformers with a voltage of 60kV and above? When welding leads for transformers with a voltage of 60kV and above, the following precautions should be taken: Before welding the leads, it is essential to wrap the base of the leads to be welded with wet
