The generator sets are installed to operate under one or combination of the following operation modes as specified in the Bill of Quantities and/or Drawings. The operation modes described in general hereinafter shall conform to those described in Section 14.0 – Generator Set Control Board and Generator Set Controllers.
(1) Continuous operation mode;
(2) Standby operation mode;
(3) Parallel operation mode
17.1 CONTINUOUS OPERATION MODE
The generator set is started by pressing push-button START. This push-button has to be pressed until the start-up speed is reached. By pressing push-button STOP, the generator is stopped immediately. The STOP command remains active throughout the stopping time. In OFF mode the generator set cannot be started.
17.2 STANDBY OPERATION MODE
In AUTO mode, when the mains supply from Licensee or Supply Authority fails or when the mains supply voltage falls below 15% of the rated voltage, the voltage sensing control relays shall operate to start the generator set automatically in 5 seconds (timer t1). After the speed and voltage of the generator set are within the normal limits, the main contacts of the automatic transfer switching equipment (ATSE) shall be closed after a time delay of 10 seconds (timer t2). When the normal mains supply is restored, the ATSE shall change over to the normal mains supply position after a time delay of 3 minutes (timer t3). After the changeover has taken place the generator set shall continue to run for 5 minutes (timer t4) before it shuts down automatically. Unless otherwise specified, the timers t1, t2, t3 and t4 shall be set as stated above. In all events the generator set supply shall not be allowed to run in parallel with supply from the Licensee and/or Supply Authority.
17.3 PARALLEL OPERATION MODE
The generator sets shall provide for automatic duty cyclic operation. In continuous operation mode, the pre-selected lead generator set shall start manually and then follow by the second generator set automatically. In the standby operation mode, the pre-selected lead generator set is started automatically. Then generator sets are synchronised to run in parallel, automatically or manually as predetermined with the closing of the generator set circuit breakers. When the generator sets are running in stable conditions, the main generator set supply circuit breaker is then closed, automatically or manually as predetermined, to provide electrical supply to the main switch board.
After the loads are connected to the generator sets, the active and reactive load shall be shared automatically between the two generator sets. At pre-set loading conditions, automatic load transfer shall take place where full load shall be transferred to the selected lead generator set. After the full load is transferred to the selected lead generator set and the lead generator set is running in stable conditions, the other generator set shall automatically shut down after the predetermined time. In the event the load increases and reaches the pre-set value, the second generator set shall start-up, synchronise and share the load automatically. For a pre-set condition, the lead generator set is allowed to run continuously for a set time (after 8 hours operation). Thereafter, the second generator set shall automatically start up, synchronise with the lead generator set and share the load. Full load shall then be transferred to the second generator set. The lead generator set shall automatically stop at predetermined time. Vice versa operation shall take place after a set cycle time.
In the case of continuous operation mode, when STOP command is activated, the generator set circuit breakers shall open and the generator sets shall shut-down insequence automatically. In standby operation mode, the generator sets shall shut-downin sequence automatically after load connection to the mains on restoration of the supplyfrom the Licensee or Supply Authority.Generator set can also be selected to operate singly in the event the othergenerator set is out of service.