The building electricity power supply is fed through Pencawang Elektrik No. 9 (PE09) which houses circuit breakers, step-down Cast Resin transformers and Low Voltage Switch Board. The power supply is also back up by a stand-by generator set. As the building M&E equimpent and services are almost ready to be tested and commissioned, its electrical infrastructure contractor is also busy completing the installation. The pre-testing and commissioning of sub-station equipment are being carried out by the Electrical Service Contractor engaged by the electrical contractor who was awarded the job via an open tender system.
All the 11-kV system for the building which comprises of 11-kV power cables, vacuum circuit breakers (VCB), 2 x 750 KVA 11/0.433-kV transformers must be fully tested before putting them into service. The operation of the VCBs can be carried out via Remote Control Panel (RCP) and the transformers are protected by Digital Temperature Relays. The VCBs are also equipped with Schneider SEPAM 1000+ OC/EF relays.
The following Basic Site Tests are being carried out on the high voltage equipment BEFORE they are put into service :
A. 11-kV Underground Cable - Insulation, phasing & Pressure Test (AC - VLF);
B. VCB - Insulation(1), Vacuum Check, Pressure Test, Insulation Test(2). Check on limit switches, tripping coil, heaters, meters, indicators, etc.
C. Transformer - Insulation and Ratio Test, Temperature Relay tests (Alarm & Trip)
D. RCP - Operation and status of VCB and Earth Switch.
E. Earthing/Grounding Test - ensure low Earth Impedance on Main Earth Bar and Transformer Star Point earth;
F. Protection Relays - CT Tests and SCIT Tripping Test;
G. Safety Clearances of all HT cables, transformer housing, terminations, etc.
H. DC Supply System - battery voltage, charger and capacity.
I. Others : Rubber mat, as-built drawing, Danger sign, No-Entry sign, CPR Chart, No Smoking sign, vermin-proof netting, cable trenches, trrench covers.
Once the Service Engineer has verified that all equipment tested are safe to be energised (via Form H), the HT equipment (all initially in OFF state) will be energised to receive electricity supply in the following Switching Sequence :
1. Switch ON supply from existing sub-station to the Incomer VCB (OFF position);
2. Verify 11-kV Voltage
3. Switch ON Incomer VCB (VCB 9B);
4. Verify voltage on busbar
5. Switch ON VCB 9C
6. Verify outgoing cable is energised;
7. Switch ON supply to Transformer No. 1 (VCB 9A)
8. Verify Voltage and Phase Rotation at LV Board;
9. Switch ON supply to Transformer No. 2 (VCB 9D)
10.Verify Voltage and Phase Rotation at LV Board.
11. Subsequent switching on LV Board will then be carried out.