What are the requirements of the Cummins diesel generator set as an emergency (standby) power station

Cummins Diesel Generator Set is mainly used as Emergency (Standby) Power Station.

The power supply system of emergency power station is generally not allowed to operate in parallel with the municipal power grid.Therefore, electrical and mechanical interlocking devices should be installed between the main circuit breaker of emergency generator set and the circuit breaker of municipal power supply to prevent misparallel connection between emergency power station and municipal power grid.Emergency units only automatically supply power to emergency loads (i.e. first-class engineering loads) when power failure occurs in the city.

When the city's power grid fails and the emergency diesel generator starts up and runs, the emergency load should not be greater than the rated output capacity of the diesel generator set.The emergency load of the first batch of automatic operators should not exceed 70% of the rated capacity of generators, which is the secondary load originally supplied by the municipal power grid.When the power is cut off automatically, the other part of the emergency load should be connected manually to avoid overload after the emergency diesel generator starts running. Generator distribution system should be equipped with special distribution buses for emergency load. Radial distribution system is generally used.

Emergency power supply and municipal power supply should set up automatic switching switch at the power supply end. For some important loads which must ensure power supply, double power supply and double circuit should be used to switch automatically at the load side (at the last level of load distribution box) when line failure occurs. In the national standard GB50045 "Code for Fire Protection of High-rise Civil Architectural Design", it is stipulated that two power supply or two circuit lines of fire-fighting electrical equipment should be switched automatically at the last level of distribution box. Self-starting devices shall be provided for self-contained power generation equipment.

The power supply system of two municipal power supply transformers and one emergency diesel generator unit is divided into three sections of buses, and the third section of buses is emergency buses. Contactors 114 M and 2KM are equipped with electrical and mechanical interlocking devices.

Under normal conditions, the emergency load is supplied by one or two buses, and the emergency buses are standby. When the power supply in both cities is cut off, the emergency diesel generator set starts automatically and supplies power to the emergency load.

There are many substations in the large-scale project, and only one power supply system diagram of two diesel generator emergency power stations is set up. Emergency power stations lay special distribution lines to each substation. Under normal circumstances, emergency load is supplied by each substation, and emergency power stations do not work. 

When the city power grid of a substation is out of power for some reason, the units of the emergency power station start up and supply power to the emergency load of the power station. The city power grid and the emergency power station implement electrical and mechanical interlocking at the load side.