Wind Power Impact on Power System Dynamic Performance

Abstract

It is well known that wind power is one of the major sources of renewable energy with a remarkable contribution to the installed capacity of electrical power systems. In this chapter, the impact of large scale wind power generation on the dynamic performance especially of weak and/or islands power systems are presented. Weak or Autonomous power systems, like the ones operating in idiomorphic areas or in islands, face increased problems related to their operation and control, [Hatziargyriou, N. & Papadopoulos, M. (1997)]. In most of these systems, the real cost of electricity production is much higher than in interconnected systems due to the high operating costs of their thermal generating units, mainly diesel and gas turbines, and the import and transportation costs of the fuel used. Security is also a major concern, since mismatches in generation and load and/or unstable system frequency control might lead to system failures, easier than in interconnected systems, [Hatziargyriou, N. et al. (1997)]. Although under ongoing energy policies wind power exploitation appear particularly attractive, the integration of a substantial amount of wind power in isolated electrical systems needs careful consideration, so as to maintain a high degree of reliability and security of the system operation. The main problems identified concern operational scheduling (mainly unit commitment) due to high production forecasting uncertainties, as well as steady state and dynamic operation disorder, [Dialynas, E. et al. (1998)]. These problems may considerably limit the amount of wind generation that can be connected to the power systems, increasing the complexity of their operation. Thus, next to the more common angle and voltage stability concerns, frequency stability must be ensured, [Hatziargyriou, N. et al. (1998)]. This depends on the ability of the system to restore balance between generation and load in case of a severe system upset with minimum loss of load. Dynamic simulation studies are the first step in determining the level of wind power penetration in power systems. Analytical studies are required in order to derive security rules and guidelines for the optimal operation of each system [Arrilaga, J. & Arnold, C.P. (1993)]. Simulations of a power system dynamic performance mainly cover voltage and frequency calculations under several abnormal operating conditions, start-up or sudden disconnection of wind generation, wind fluctuations and short circuits on the transmission and distribution network. In order to ensure the maximum exploitation of the available renewable power sources and to operate systems with increased wind power penetration in