Smart microgrid grid power quality improvement and reduction of fuel consumption by application of adjustable speed generation system

Paper presents power conditioning system that is applied to smart microgrid supplied from renewable energy sources (RES). Usually the microgrid is equipped in Diesel driven synchronous generator that operates with fixed speed and provides demanded power and stabilizes output voltage. However, when the power of the RES is rising the Diesel engine specific fuel consumption is also rising and then Diesel engine efficiency drops. So such a system consumes a lot of fuel what reduces efficiency of the microgrid. Therefore, instead of fixed speed generation set, an adjustable speed generation system is applied. So the topology of the adjustable speed generation system is developed. Paper delivers principle of Diesel engine variable operation that speed is adjusted to demand of power and controlled load torque follows the areas of low specific fuel consumption and then save a lot of fuel in comparison to fixed speed. An example of calculation of fuel consumption by generation units operating with fixed and adjustable speed based on brake specific fuel consumption maps has been made. The calculation confirms that the application of adjustable speed generation systems results in significant fuel savings.