How to Specify GIS High-Voltage Test Equipment
Define test voltage, waveform, specimen capacitance, measurement background, space and safety interfaces before requesting a test-system design.
Selection note: use this guide to compare technical requirements. Confirm catalog ranges, typical values and standard clauses against the model, edition and agreed test conditions; project acceptance follows the approved drawings and technical agreement.
On this page
- 01Why do GIS factories choose Gas-Insulated Metal-Clad Test Transformers (GTTS) over open-air systems?
- 02How does a Metal-Clad Lightning Impulse Generator (MIG) fire clean 1.2/50 us waves up to 4200 kV?
- 03What is the best system for on-site GIS commissioning withstand and SF6 micro-leakage diagnostics?
- 04How are continuous current temperature-rise tests performed on GIS busbars and bushings?
- 05Frequently asked questions
- 06Standards & sources
In short
Compare test sources by the specimen, waveform, capacitance, connections and measurement background; verify the offered laboratory and report scope separately.
- A metal-clad test transformer may integrate the source, coupling capacitor and divider; request measured background PD and a layout comparison for the offered configuration.
- Metal-clad lightning impulse generators (MIG, 900 kV to 4200 kV, up to 315 kJ) achieve < 1.5 uH/stage inductance so standard 1.2/50 us waves can be fired into high-capacitance GIS bays.
- Hermetic SF6 spark gaps with laser-triggered automation make impulse firing independent of room dust, humidity and high altitude.
- Variable-frequency series resonance (GRDS, 20 to 300 Hz, 300 to 1250 kV) enables mobile on-site GIS handover testing with pure sine waves (<= 1.0% THD).
- Open-type power-frequency (PFTS), open impulse (OIG) and high-current temperature-rise systems (HCTS) complete the factory type-test suite.
Start with the test object, capacitance, waveform, voltage, measurement background and connection layout; request a configuration-specific proposal.
01Why do GIS factories choose Gas-Insulated Metal-Clad Test Transformers (GTTS) over open-air systems?
A metal-clad system can connect directly to a GIS test port and contain high-voltage parts in an earthed enclosure. Compare room dimensions, background PD, access and cost for the offered configuration.
The catalogue lists GTTS capacity options from 200 kVA to 2000 kVA and short-circuit impedance at or below 5% for specified configurations. Confirm the offered model, test-bushing interface and source requirements against the intended IEC 60507 procedure; request customer references separately.
02How does a Metal-Clad Lightning Impulse Generator (MIG) fire clean 1.2/50 us waves up to 4200 kV?
The impulse waveform depends on the generator circuit and the capacitance of the test object. Ask for the offered MIG circuit, load range and measured waveforms at the required voltage.
A metal enclosure changes clearance and environmental exposure; verify the GIS connection, switching arrangement and shielding on the proposed layout.
- Standard waveforms: 1.2/50 us lightning full wave, chopped wave, and 250/2500 us switching impulse wave.
- MIG vs OIG choice: choose metal-clad MIG for direct GIS docking and compact shielded halls; choose Open-Type Impulse Generators (OIG, 300 kV to 4200 kV) for outdoor insulator strings and air-insulated apparatus.
| System Code & Name | Output Rating | Key Performance Metric | Primary Application |
|---|---|---|---|
| GTTS Metal-Clad Test Transformer | 200 kV to 1250 kV (200 to 2000 kVA) | Confirm measured background PD and room dimensions by configuration | Direct-docked GIS & bushing PD routine test |
| MIG Metal-Clad Impulse Generator | 900 kV to 4200 kV (45 to 315 kJ) | Inductance < 1.5 uH/stage; laser gap | 1.2/50 us & 250/2500 us GIS impulse testing |
| GRDS On-Site Resonance & Diagnostic | 300 kV to 1250 kV (20 to 300 Hz) | 1 pC UHF PD + 0.01 ppm SF6 leak sensor | Substation handover test & live diagnostics |
| PFTS Power-Frequency Withstand | 300 kV to 1250 kV | Low impedance for dry/wet/pollution test | Insulator, bushing & apparatus AC withstand |
| OIG Open-Type Impulse Generator | 300 kV to 4200 kV | Automated optical-fiber PLC console | Air-insulated HV laboratory impulse testing |
| HCTS High-Current Test System | Low-voltage high-current AC loop | Multi-point thermal equilibrium logging | GIS busbar, breaker & bushing thermal test |
03What is the best system for on-site GIS commissioning withstand and SF6 micro-leakage diagnostics?
Use a resonance source sized to the GIS capacitance for withstand testing, then specify separate PD and gas-leak measurement channels and their acceptance plan.
At resonance, the reactor and GIS capacitance exchange reactive power, which can reduce the external supply required for a specified test. Compare the proposed source, test duration and measured waveform; where UHF PD channels are included, review sensor placement and recorded signals before diagnosing a defect.
“Buyer check: define specimen capacitance, test voltage, waveform, background noise and room layout before comparing systems.”
04How are continuous current temperature-rise tests performed on GIS busbars and bushings?
Pass the specified current through the complete busbar or bushing test loop, record temperatures at agreed contact and conductor points, and assess the stabilized rise against the project test clause.
For an HCTS quotation, specify the current range, conductor and contact geometry, sensor positions, ambient correction and test duration. Laboratory accreditation, if required, must be checked separately for the named testing facility and its scope.
Applicable EONOVA Equipment
Conclusion
Select test sources by object capacitance, required waveform and duty; verify measurement background, connections and calibration for the offered configuration.
Talk to an EONOVA engineerFrequently Asked Questions
How should laboratory space be compared for metal-clad and open-air test systems?
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Compare the complete equipment and specimen layout: high-voltage clearance, GIS docking, ceiling height, service access and shielding. Request dimensioned plans for both options.
Why is low stage inductance (< 1.5 uH/stage) critical when impulse testing GIS switchgear?
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Loop inductance and test-object capacitance affect impulse-wave overshoot and front time. For the proposed MIG and GIS bay, ask for the specified load capacitance, circuit data and measured waveform under the agreed test conditions; a stage-inductance figure alone does not prove compliance.
Can the GRDS on-site system locate both partial discharge defects and SF6 gas micro-leaks during one visit?
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Yes. The GRDS trailer/container integrates a 20 Hz to 300 Hz series resonance HV power supply with multi-channel UHF and ultrasonic PD sensors (1 pC sensitivity) to triangulate internal insulation defects during withstand testing, plus a 0.01 ppm laser photoacoustic/NDIR SF6 analyzer to pinpoint seal micro-leaks.
Standards & Sources
- [1]IEC 60060-1 & -2: High-voltage test techniques: General definitions, test requirements and measuring systems
International Electrotechnical Commission (TC 42)
Supports: AC withstand, 1.2/50 us lightning impulse and 250/2500 us switching impulse tolerances and divider calibration.
- [2]IEC 60270: High-voltage test techniques: Partial discharge measurements
International Electrotechnical Commission (TC 42)
Supports: Shielding, coupling capacitor and <= 0.3 to 0.5 pC background noise requirements.
- [3]IEC 62271-203: Gas-insulated metal-enclosed switchgear for rated voltages above 52 kV
International Electrotechnical Commission (TC 17)
Supports: Factory routine dielectric tests, on-site commissioning voltage levels and SF6 leakage limits.
- [4]IEC 62271-1: High-voltage switchgear and controlgear: Common specifications for alternating current switchgear
International Electrotechnical Commission (TC 17)
Supports: Continuous current temperature-rise test procedures and hot-spot limits verified by HCTS.
Selection guidance for buyers. Confirm specifications and test evidence for the quoted model and supplying entity.
