As a core device in the power system, transformers play a decisive role in ensuring stable power supply. Affected by complex operating environments such as temperature fluctuations, humidity changes and long-term load pressure, transformers are prone to various faults. Mastering scientific fault diagnosis and handling methods, and conducting regular preventive tests are essential to extend the service life of transformers and ensure the safety of the power grid. This guide focuses on practical technologies, with special emphasis on the application of these methods in 33kv transformer and 315kva transformer.
JINSHANMEN TECHNOLOGY CO., LTD is a professional manufacturer of power transmission and distribution equipment. The company mainly produces oil immersed power transformers, dry-type power transformers, oil immersed three-dimensional coiled power transformers, dry-type three-dimensional coiled power transformers, mining explosion-proof dry-type transformers, mining explosion-proof mobile substations, amorphous alloy power transformers, on load capacity regulating power transformers, locomotive dry-type transformers, as well as prefabricated substations, modular substations, wind energy box type substations, high and low voltage switchgear and other transmission and distribution equipment. With rich production experience and technical accumulation, the company provides reliable equipment support for global power projects, including 33kv transformer and 315kva transformer with high efficiency and stability.
1. Preventive Test Methods and Principles
Preventive tests are the first line of defense to avoid transformer faults. For different types of transformers such as 33kv transformer and 315kva transformer, the test standards and key points are basically consistent, but need to be adjusted according to voltage level and capacity characteristics.
1.1 Insulation Resistance Measurement
Use an insulation resistance tester to apply a certain DC voltage to the transformer windings and measure the leakage current to calculate the insulation resistance value. This method can effectively detect insulation aging, moisture and other problems. For 33kv transformer, due to its high voltage level, a 2500V megohmmeter should be used for testing, and the insulation resistance value should be converted according to the temperature to ensure compliance with the standard. For 315kva transformer used in industrial and commercial scenarios, regular insulation resistance testing can avoid sudden insulation breakdown caused by harsh operating environments.
1.2 Winding Series Impedance Measurement
Adopt series resonance method or eddy current method to measure the winding impedance. The change of impedance value can reflect faults such as winding short circuit and open circuit. When testing the 33kv transformer, special attention should be paid to the influence of short-circuit impedance on the operation stability, and the test data should be compared with the factory parameters. For the 315kva transformer, this test can effectively find the winding deformation caused by overload, ensuring the safe operation of the equipment.
1.3 Transformation Ratio Measurement
Use a tap changer tester to measure the transformation ratio of the transformer, so as to ensure that the output voltage meets the design requirements. Abnormal transformation ratio is often caused by inter-turn short circuit of windings or poor contact of tap changers. For 33kv transformer with no-load tap changer, the transformation ratio test should be carried out at each tap position. For 315kva transformer in distribution system, stable transformation ratio is the key to ensure the normal operation of terminal equipment.
1.4 DC Withstand Voltage Test & Partial Discharge Test
The DC withstand voltage test applies high DC voltage higher than the working voltage to test the insulation strength of the transformer, which is particularly important for 33kv transformer. The partial discharge test detects partial discharge signals through ultrasonic and electromagnetic wave technology, and finds insulation defects such as bubbles and cracks without damaging the insulation performance. These two tests are indispensable for ensuring the long-term safe operation of 33kv transformer and 315kva transformer.
2. Common Fault Analysis and Solutions
2.1 Winding Faults
Common faults include inter-turn short circuit, winding grounding and phase-to-phase short circuit, which are mostly caused by insulation damage during manufacturing and maintenance, or insulation aging due to poor heat dissipation. For 33kv transformer, once a winding fault is found, the damaged winding should be replaced in time and the insulation should be repaired. For 315kva transformer, strengthening daily load monitoring can reduce the occurrence of winding faults caused by long-term overload.
2.2 Bushing Faults
It is mainly manifested in explosion, flashover and oil leakage, which are related to poor sealing, moisture deterioration of insulation and improper configuration of respirators. The solution is to replace the damaged bushing and repair the sealing structure. For 33kv transformer bushings, regular cleaning and insulation detection should be carried out to avoid flashover accidents. For 315kva transformer, checking the sealing performance of the bushing root can effectively prevent oil leakage.
2.3 Other Faults
Core faults are mostly caused by insulation damage between silicon steel sheets, which need to be repaired or replaced. Gas protection faults should be distinguished: if there is an internal fault, the transformer should be shut down for inspection; if it is a secondary circuit fault, the circuit should be repaired. Overload faults should first put into the standby transformer, then check the cause, and strengthen load management to avoid overloading. These handling methods are universally applicable to 33kv transformer and 315kva transformer.
3. Summary
Preventive tests are the key to ensuring the safe operation of transformers. For 33kv transformer and 315kva transformer which are widely used in power grid and industrial distribution, regular preventive tests and scientific fault handling can not only find potential problems in time, but also provide a basis for equipment maintenance. JINSHANMEN TECHNOLOGY CO., LTD is committed to providing high-quality transformers and supporting technical services, helping users reduce fault rates and ensure the stability of the power system through professional technology and reliable products.