GIS combined electrical appliances and power transformers are key core equipment of high-voltage substations, with complex internal structures and high insulation performance requirements. Once partial discharge defects occur, it will lead to serious equipment failures and large-scale power outages. Live-line partial discharge testing can realize early warning of internal defects of GIS and transformers without power failure, which is an important guarantee for the safe operation of high-voltage power grids.
Partial Discharge Features in GIS Equipment
GIS equipment is fully sealed and filled with SF6 insulating gas. Its internal partial discharge is mainly caused by metal foreign bodies, insulation defects, poor sealing and gas dampness. Different from open equipment, GIS discharge signals are hidden inside the metal shell, with no obvious surface discharge phenomena, and it is impossible to detect through traditional visual and ultrasonic simple detection. High-sensitivity professional detection methods are required for effective identification.
UHF Detection for GIS Partial Discharge
UHF ultra-high frequency detection is the most authoritative and effective method for GIS partial discharge testing. Internal PD defects will radiate ultra-high frequency electromagnetic signals through flange gaps and insulation windows. UHF sensors can accurately capture these weak high-frequency signals, effectively shielding external low-frequency electromagnetic interference, and realize accurate positioning and quantitative analysis of GIS internal discharge defects.
Partial Discharge Testing Solutions for Power Transformer
Power transformer partial discharge mainly occurs in winding insulation, iron core and grounding loops. For internal insulation discharge defects, UHF sensors are used to capture high-frequency electromagnetic signals; for grounding loop discharge and floating potential defects, HFCT high-frequency current sensors are clamped on the transformer grounding wire to collect pulse current signals. The combination of UHF and HFCT dual detection realizes full coverage of transformer PD defects.
Sensor Matching for Different Defect Types
For GIS metal foreign body discharge and insulation void discharge: prioritize UHF sensor detection; for transformer grounding loop abnormal discharge: use HFCT sensor; for transformer surface corona discharge and loose part vibration discharge: cooperate with AE ultrasonic sensor for auxiliary verification. Reasonable sensor matching can maximize detection accuracy and efficiency.
MOEORW‑Wi900PD supports external UHF, HFCT and AE sensors for GIS and transformer on‑site partial discharge measurement.
