Governor tuning and digital deflector control of Pelton turbine with multiple needles for power system studies
In this study, a Pelton turbine and governor system dynamic model with deflector control was developed. The Pelton turbine established reasonable parameters for the deflector control model to effectively restrain unit frequency rise, which played the role of a similar thermal power overspeed protection. Since a Pelton turbine typically contains multiple needles, the concept of average needle opening was employed in the model. An improved orthogonal learning biogeography-based optimisation (IOLBBO) algorithm, which adopted good point set to initialise habitat, elites to maintain the tactics, and an orthogonal learning strategy to improve global search capabilities, was developed. The parameters were identified with the IOLBBO algorithm based on measured data. To develop the model in this study, various types of Pelton turbine and governor system models with different refinement degrees were analysed. Large fluctuations, like a load rejection process, verified the validity of the established deflector control model. Additionally, digital deflector control characteristics were achieved by computer programming. The non-linear Pelton turbine and water diversion system model with an elastic water hammer model that considered a non-linear relationship between the average needle opening and mechanical power developed in this study demonstrated superior simulation results in power system stability analysis.