Load sharing control between PV power plant and diesel generator to mitigate effect of PV fluctuation using PID algorithm

The Sumba smart microgrid project was built in 2012 as a research means to demonstrate PV power plant integration into utility grid that implemented modern control and information technology to reduce effects of intermittency PV output. It consists of PV, battery, diesel generator, and SCADA subsystem. Since battery subsystem had a problem in its PCS system then some changes in compensation algorithm are needed to maintain grid reliability. In this paper, PV-diesel load sharing algorithm was added to the diesel generators operation control to compensate fluctuation of PV output, with its main purpose is to deliver constant power to the grid. Load sharing control system receive the data of PV output and adjust the diesel power output by controlling governor and AVR (Automatic Voltage Regulator). In this research, the total power output from the system is limited to 150kW. For example, if PV produced 100kW, then diesel generator operation controller drove the diesel generators to produce 50kW. Digital power meters were installed on PV and generator to measure active power, voltage, frequency, and power factor. These data were used as input parameters for load sharing control. Settings up and down the diesel generator power output is done automatically by the PLC (programmable logic controller) module using PID (proportional integral derivative) algorithm. Testing is done by on or off the inverter to simulate the rise and fall of power from PV output. Testing results show that diesel can compensate PV power reduction relatively fast. The proposed method could be used to leveling PV output power fluctuation and reduce the frequency deviations and maintain resilience on the microgrid.