Switchgear apparatus prophylaxis (medium voltage prefabricated subtations)
Specialized engineering services for medium voltage prefabricated substations in operation
NOVA INDUSTRIAL S.A. experts evaluate the technical state of the switchgear apparatus in service based on the analyze of the history data (concerning construction, factory tests, tests for putting into service or for preventive maintenance, incidents in operation, etc.), in addition to tests and measurements specific to each type of switchgear.
Tests and measurements specific to MEDIUM VOLTAGE PREFABRICATED SUBSTATIONS:
- verification of the construction and the electrical equipment;
- verification of the tightness;
- operation tests (locally and from distance) for the following components: circuit-breaker, bus-bar and line switches/disconnectors, earthing switches;
- verification of the interlocks (from the control cubicle), respectively of the signalizations of the SF6 gas pressure decrease (on the metering panel), for the SF6 gas insulated equipment;
- verification of the current transformers: terminal markings, polarity, ratio error, volt-ampere characteristic;
- verification of the voltage transformers: terminal markings, ratio error, off-load current;
- verification of the motion characteristics of the built-in switchgear apparatus;
- measurement of the ohmic resistance of the current path;
- insulation test made at the power frequency or direct voltage of the main and secondary path of current ;
- dew point determination for the SF6 gas (for the equipment insulated with the SF6 gas).
The tests characteristic to the off-line defectoscopy methods are done using NOVA TEST, the specialized equipment designed and manufactured by experts from NOVA INDUSTRIAL S.A.