Some developing countries like South Africa and India face extended hours of load shedding and complete blackouts. And even Western countries like the USA face the same predicaments as seen in last year’s Texas blackout or California fires.
Many companies have started installing solar installations to increase local production and reduce their dependency on backup diesel generators to address this problem. They try to ensure continuous power supply on-site through the use of solar panels in addition to the backup diesel generators.
In this case, they need to design a solution that makes the solar panels work in parallel with the diesel generators to meet power demand in the most optimized manner.
Solar Diesel Hybrid power systems can not work correctly without a controller. It is necessary to use a Solar Diesel (SD) controller to supply power, especially during a blackout. It allows the parallel operation of solar panels and a backup diesel generator.
In the case of microgrids, it is also imperative that only one energy source be grid forming. It means that this component sets the voltage and frequency of the whole grid. When multiple energy sources are tied together, several protective components are placed in the network to avoid problems such as low frequency, distorted current flow, and reverse power flow. The SD controller is essential in such scenarios as it detects which source of energy is behaving as grid forming (Grid or Diesel Backup generators).
In case of a blackout, the SD controller will curtail the PV production to ensure minimum generator set loading (around 30% of nominal power) and prevent the risk of reverse power.
When solar generation capacity is added to reduce fuel consumption without adding a storage battery, the output power of the PV inverters should be controlled to allow for optimal operation with generators while avoiding the reversal of power from the solar to the generators.