Emergency Generator Panel — Container Vessel

We renewed the PLC of the emergency generator panel on a container vessel with a Siemens S7-1200. The program of the existing PLC had been lost and the automatic control of the generator was out of service. The panel combines the control of the 170 kW, AC450V 3-phase 60 Hz emergency generator, the feed-back from the emergency switchboard to the main switchboard (MSB) and the shore power connection in one section.

The existing PLC was removed and a Siemens S7-1200 CPU with an I/O module was mounted on the DIN rail. The fuse, relay and contactor infrastructure of the panel, as well as the overcurrent, short-circuit and undervoltage protection relays, were kept; the complete control logic moved to the new PLC.

The program was written from scratch in TIA Portal. All control functions run on the PLC: the automatic start sequence of the generator, ACB closing, feed-back to the MSB, bus-tie and shore power interlocks, the ENG START/STOP, ACB OPEN/CLOSE and BUS-TIE CLOSE commands in MANU mode, the indicator lamps and the alarm buzzer. In AUTO mode the generator starts automatically on a main bus blackout; once voltage and frequency are stable the ACB closes and the emergency switchboard is energised.

All commissioning tests were carried out in the presence of the surveyor: the automatic start sequence on load using the EG sequence test button on the panel, the blackout test and the feed-back scenarios to the MSB were verified on board.