What’s theCauses of Partial Discharge Faults in Tap Changers？

Local discharge faults in tap changers can be caused by various factors, typically related to the deterioration of insulation performance, external overvoltages, and material quality issues. The following are some common causes:

Reason

●Deterioration of Insulation Performance:

The insulation performance of a tap changer is fundamental to its normal operation. A decline in insulation performance can lead tolocal discharge phenomena. This deterioration is often due to prolonged use, environmental factors, aging, or inherent defects in the insulation material itself. As insulation performance deteriorates, local discharges increase, potentially leading to flashover. Flashover refers to electrical discharges forming arcs in insulation materials or air, which can cause localized overheating and, in severe cases, damage the tap changer.

●Lightning Overvoltages or Switching Overvoltages:

Lightning overvoltages and switching overvoltages are common external voltage anomalies. These overvoltages can exceed the insulation design capacity of the tap changer, resulting inlocal discharges orinsulation breakdown. Lightning overvoltages are typically caused by transient high voltages from lightning activity, while switching overvoltages may occur due to power system operations, such as switching sources or sudden load changes.

●Mechanical Forces:

Tap changers may be subjected to mechanical forces, such asvibrations,impacts, orimproper installation. These forces can cause deformation or damage to the insulation materials, increasing the risk of discharge.

●Quality Issues with Insulation Materials:

Insulation materials within the tap changer, if of substandard quality, may deform or degrade after repeated operations. For instance, the insulation materials in the tap selector or switch may deteriorate due to material defects or prolonged use, leading to reduced insulation resistance and subsequent local discharges.

●Internal Structural Issues:

Poor contact between the stationary and moving contacts within the tap changer or design and manufacturing defects can also lead to local discharges. Such issues may cause excessive DC resistance in the windings, creating an unstable electrical environment that further triggers discharge phenomena.

Measures

To prevent and mitigate local discharge faults in tap changers, measures to enhance insulation levels are necessary. The following methods can improve insulation performance:

●Regular Maintenance and Inspection:Periodically inspect the insulation condition of the tap changer and promptly replace aging or damaged insulation materials.

●Enhanced Overvoltage Protection:Install appropriate overvoltage protection devices, such as lightning arresters and voltage protectors, to mitigate the effects of lightning and switching overvoltages on the tap changer.

●Improved Design and Manufacturing Processes:Ensure that the design and manufacturing of tap changers meet high-quality standards, using high-quality insulation materials and avoiding structural defects.

●Enhanced Operational Practices:Follow standard operating procedures for the tap changer to prevent overvoltage issues caused by improper operation.

By implementing these measures, local discharge faults in tap changers can be effectively reduced, thereby enhancing their reliability and service life.

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LuShan, est.1975, is a Chinese professional manufacturer specializing in power transformers and reactors for 49 years. Leading products are single phase and three phase isolation transformers, electrical transformer, distribution transformer, step down and step up transformer, low voltage transformer, high voltage transformer, control transformer, toroidal transformer, R-core transformer; DC inductors, AC reactors, line and load reactor, chokes, filtering reactor, and intermediate, high-frequency products. Our power transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering(furnace), central air conditioning.

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