Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

Growing Requirements for Power Transformer Cooling Systems and the Function of CoolersWith the rapid development of power grids and the increase in transmission voltage, power grids and electricity users are demanding increasingly higher insulation reliability for large power transformers. Since partial discharge testing is non-destructive to insulation yet highly sensitive, effectively detecting inherent defects in transformer insulation or safety-threatening defects generated during transporta

Insulation degradation in power equipment is generally caused by multiple factors. During operation, insulation materials (such as epoxy resin and cable terminations) gradually deteriorate due to thermal, electrical, and mechanical stresses, leading to the formation of voids or cracks. Alternatively, contamination and moisture—such as dust or salt deposition or high-humidity environments—can increase surface conductivity, triggering corona discharge or surface tracking. Additionally, lightning s

1. Maintaining and Restoring the Factory Insulation ConditionWhen a transformer undergoes factory acceptance tests, its insulation condition is at its optimal state. Thereafter, the insulation condition tends to deteriorate, and the installation phase may be a critical period for sudden degradation. In extreme cases, the dielectric strength may drop to the point of failure, leading to coil burnout immediately upon energization. Under normal circumstances, poor installation quality leaves behind

As the title suggests, when performing live partial discharge (PD) testing on Siemens GIS using the UHF method—specifically by accessing the signal through the metal flange of the bushing insulator—you must not directly remove the metal cover on the bushing insulator.Why?You won’t realize the danger until you try. Once removed, the GIS will leak SF₆ gas while energized! Enough talk—let’s go straight to the diagrams.As shown in Figure 1, the small aluminum cover inside the red box is typically th