What are the modes of operation for a diesel generator? How are they different?
A diesel generator has a range of operating modes depending on the application it needs to supply power to. These operating modes can be broadly defined, but it is also possible to have scenarios that are hybrids of these modes.
Diesel generator in Island or Standalone Mode
A diesel generator running island mode or standalone refers to a system where the generators is the sole source of power. No mains power is available. In this instance the generator is often the only source of power. It may be used to charge alternative power sources such as battery banks, in order to reduce the overall running time and fuel consumption.
Diesel generator In Standby Mode
A diesel generator standby mode works as a backup to a mains supply. When the mains fails, the generator will start running and an automatic transfer panel (ATS) will change the supply to the load from the mains to the generator. This usually involves a short period without power, unless short term backup is available, such as a UPS system.
Diesel generator in parallel with the mains
A diesel generator in parallel with the mains can be used to supply additional power when the incoming supply from the mains is insufficient to meet the load demand. It can also be used to export power to the mains to support the grid. Generators in this mode are often also used for standby in the even of a mains failure.
How do do the different operation modes effect the design?
Diesel generators with different operating modes may have different system designs. For example, a generator running in parallel with the mains will require synchronizing equipment, such as a advanced control module and a fully automatic circuit breaker.
Generators running in standby normally require a load switching system, such as an manual or automatic transfer switch, ensuring that the power from the generator is safely isolated from the mains supply. Generators running in standby are often ESP rated, but other generator ISO ratings can also be used.
Generators running in island mode are often the most basic and can run with little additional equipment. Common extra include bulk fuel tanks to allow for long periods of unattended running. These generators are often COP rated or PRP rated, depending on the load requirements.