UHF-PD-Measurement Systems on GIS with Adjustable Frequency Ranges

The commissioning, regular checks, and monitoring of Gas-Insulated Switchgear (GIS) require highly sensitive and resilient Partial Discharge (PD) measurements. The most sensitive method involves employing low-noise broadband amplifiers near PD sensors and a preprocess to filter and display the signals. Various Ultra-High Frequency (UHF) measurement systems have been developed to address the specific challenges of PD measurements in GIS, including narrowband, wideband, and medium-band approaches. Narrowband systems use tuned narrow-band filters with variable center frequencies to extract PD signals at precise frequencies within the UHF range, ensuring high signal-to-noise ratios (SNR). Wideband systems, in contrast, capture PD signals across a broad frequency spectrum, offering a comprehensive view of PD activity. Medium-band systems strike a balance between these methods by employing tuned band-pass filters with a bandwidth of 80 MHz, tailored to the resonant frequencies of PD sensors and setups. Combining wideband and medium-band approaches extends measurement coverage, particularly in monitoring applications where redundancy and reliability are crucial. In summary, the advancement of UHF measurement methods and the deployment of reliable monitoring and alarming systems have significantly improved the reliability and effectiveness of PD detection in GIS. These developments play a critical role in safeguarding the integrity and operational safety of high voltage insulation systems.