Before putting a compact substation into service (after installation or repair), perform the following inspections and tests:
Surface & cleanliness – Check for paint peeling and ensure the unit is clean inside.
Operating mechanism – Verify smooth operation; no sticking or excessive force required.
Main electrical contacts – Confirm reliable and accurate make/break action.
Auxiliary contacts – Check for correct and reliable operation.
Instrumentation & CTs – Verify correct ratios, wiring, and polarity.
Fasteners – Ensure all electrical mounting nuts are tightened.
Busbar connections – Check for good contact; inspect support insulators, clamps, and accessories for secure fastening.
Relay settings & fuses – Confirm settings meet requirements and fuse ratings are correct.
Primary & auxiliary circuit contacts – Verify alignment with the electrical schematic diagram.
Grounding & protection – Measure protective earth resistance (must be <0.1 Ω); verify meter and relay accuracy.
Insulation resistance (low-voltage & secondary circuits) – Use a 500 V insulation resistance tester; value must be ≥2 MΩ.
Transformer temperature control – Ensure the device is set to the specified operating temperature.
Capacitor & distribution system – Check capacitor enclosure grounding and overall system reliability.
Follow these steps to safely energize the compact substation:
Pre-commissioning tests – Conduct necessary tests on HV/LV distribution equipment, transformer, and metering devices. Proceed only after all tests pass.
Prepare the unit – Close the transformer mesh guard and all accessible doors. Ensure all switches are in the OFF (open) position.
Energize HV side – Close the 10 kV power supply according to operating procedures. Observe HV compartment indicators – if normal, the transformer can be put into service.
Energize LV side – Close the low-voltage main breaker. Check LV panel indications. If normal, close individual feeder breakers. The compact substation is now in normal operation.
Xinhong Electrical compact substations are designed for unattended operation, integrating reception, transformation, and distribution. Regular inspections and upkeep are essential to prevent failures.
Routine – Perform periodic visual checks, cleaning, and maintenance.
Corrosion protection – For the metal enclosure, touch up any rust spots found during inspection.
Mechanical parts – Tighten removable components; check hinges and door locks for smooth operation; apply lubricating oil as needed. Ensure internal lighting is functional.
Ventilation & cooling – Check that ventilation openings are not blocked. Verify automatic exhaust fans operate correctly. Monitor internal temperature rise – if abnormal, de-energize and troubleshoot.
Periodic testing – Follow DL/T 596 Preventive Test Code for Electric Power Equipment for scheduled tests.
Oil-immersed transformers – If the substation uses an oil-immersed transformer, perform an annual oil sample analysis.
HV load-break switches – After 20 full-load operations or 2000 no-load open/close cycles, inspect contacts, arc-quenching device wear, and mechanical performance. Repair or replace if abnormal.
LV circuit breakers – After automatic tripping, investigate the cause. Only re-energize after the fault is cleared.
Surge arresters – Conduct a preventive test each year before the rainy season.
Safety during HV maintenance – Before servicing HV load-break switches or surge arresters, always disconnect the incoming power supply to the compact substation. When inspecting the transformer, do not open the inner mesh door.
