Voltage control capabilities of biogas plants in parallel operation - Technical and economical assessment

In this study, technical and economical investigations of different autonomous voltage control strategies are conducted for biogas plants with an electrical nominal power of some 100 kWel. For the assessments, a detailed model of a common biogas CHP plant with its usual electrical characteristics is deduced. Based on root mean square simulations in a real MV/LV grid with high local DG penetration in Germany, the dynamics, limitations and technical effectiveness of active and reactive power control strategies for voltage support purposes are assessed. In a second step it is shown that this voltage support by biogas plants is capable to further increase the DG hosting capacity of a real distribution grid. A cost-benefit analysis based on 12 month RMS simulations compares the economic efficiency for the different control strategies.