Analysis of Small Signal Stability on Wind Power Integration to Integrated Nepal Power System

Abstract

In power system, the wind energy and its technology integration begins to significantly influence the power system structure and parameters. Wind energy system has diverged generator technologies than the hydro power plants which are conventional. The power system stability, steady-state, transient dynamics and small-signal dynamics will be affected considerably. When the power system dynamics is connected with the wind energy system its stability are more concerned in practical way. The wind turbines are incorporated with doubly-fed induction generator (DFIG) in modern era and, therefore, the simplified model of the DFIG incorporated with wind turbine is modelled and presented by differential algebraic relations. The model is validated against literature and references and then with the system characteristics. The power system is non-linear and therefore, it is linearized with state space relations and then incorporated with the DFIG locations and differential size. Eigen value analysis is used to identify the stability of the DFIG and voltage limits are checked whether it is under limit or not. In technical analysis, the IEEE standard test system is chosen for validation and then the paradigm is used to analyze the INPS system incorporated with wind energy system at different locations. The small signal stability, effect on voltage and power flow, and operating point variations are observed. In financial analysis, project life is considered 20 year and wind energy production variation is considered in a range which is under Betz limit of generation. Different scenario for subsidy on total cost of the system is considered during financial analysis. The wind power system is feasible only if majority is financed under subsidy. The payback period of the project is attractive under high subsidy scheme only.