GIS Partial Discharge Detection for Southeast Asian Utilities
Gas-insulated switchgear (GIS) is the technology of choice for high-density substations across Southeast Asia — from Singapore’s urban grid to new transmission projects in Vietnam and the Philippines. The same sealed design that makes GIS compact also makes internal faults invisible: once a defect discharges inside an SF6 compartment, the first sign can be a full outage. This is why GIS partial discharge detection with UHF and acoustic methods has become standard practice for the region’s utilities.
Why UHF Is the Primary Method for GIS
Partial discharge inside GIS radiates electromagnetic waves in the UHF band (300 MHz–3 GHz), which travel through the metal enclosure and exit at dielectric apertures such as insulators and inspection ports. UHF sensors mounted at these apertures detect the signal with high sensitivity, inside or outside the gas compartment, with no outage required.
UHF vs Acoustic Detection
| Feature | UHF | Acoustic (AE) |
|---|---|---|
| Signal origin | Electromagnetic wave | Structure-borne vibration |
| Sensitivity | Very high, detects pC-level activity | Moderate, best for location |
| Installation | At apertures, inside or outside | On enclosure surface |
| Online monitoring | Excellent | Good |
| Best role | Detection and trending | Confirmation and location |
The strongest programs use both: UHF for sensitive detection and trending, acoustic for confirming and localizing the source before outage planning.
Sensor Placement in Southeast Asian GIS Substations
- Busbar compartments: sensors at each busbar section for complete coverage
- Disconnector and breaker compartments: highest historical defect rates
- Cable terminations and bushing ends: transition points between GIS and cables
- Inspection ports: retrofit-friendly positions for existing substations
HUWOR’s built-in UHF partial discharge sensor is designed for permanent installation at standard GIS apertures, with output compatible with both our handheld detectors and online monitoring systems.
Deploying a GIS PD Monitoring Program
Phase 1 — Baseline
Survey the substation with portable UHF and acoustic instruments during commissioning or routine access, and record reference levels for each bay.
Phase 2 — Permanent Monitoring
Install UHF sensors on critical bays and connect them to the monitoring platform. Set alarms based on the baseline plus a safety margin, not on generic thresholds.
Phase 3 — Trend Review
Review phase-resolved patterns and trends monthly. Rising discharge activity, especially synchronized with load or switching, justifies planned inspection before failure.
Standards and Best Practice
Measurement practice follows IEC 60270 principles and CIGRE guidance for UHF-based GIS monitoring. For a deeper technical reference, download the HUWOR partial discharge white paper. To discuss sensor configuration for your substations, contact our export team or see the Southeast Asia solutions overview.