Tham khảo tài liệu 'wind power impact on power system dynamic part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Wind Power Impact on Power System Dynamic Performance 403 Fig. 8. Diesel-Gas speed control system Af is the per unit frequency change fo 50Hz . Pm is the mechanical power of the diesel motor. R is the droop of the speed governor. b. Steam unit The block diagram of Fig. 9 represents the speed governor system considered for each steam unit. Fig. 9. Steam speed control system Af is the per unit frequency change fo 50Hz Pm is the mechanical power of the steam turbine. The transfer function for the governor includes speed relay and transient droop. The steam turbine is represented as single reheat type whose transfer function is Gt s l 1 Trh-S 8 FHP is the fraction of total turbine power generated. TRH is the time constant of reheater. For the simulation procedure an integrating control parallel to machine droop is added to the speed controllers of Fig. 8 and Fig. 9 as shown in next Fig. 10. Fig. 10. Addition of integrating control block c. Voltage regulator The standard DC1 model of IEEE is considered for the voltage regulator of each generator of the system. 404 Wind Power d. Asynchronous generator equations Wind generators are simulated mainly as induction machines with a sort-circuited double cage rotor. These induction machines are derived from synchronous machines with the excitation winding short-circuited. Besides this the machines are assumed to be perfectly symmetrical. The initial slip corresponds to the intersection of the electrical torque curve and the opposing mechanical torque as shown in Fig. 11. The mechanical power is a linear function of the asynchronous wind generator speed Pm 9 In steady state conditions and in case of a disturbance where the wind remains stable the mechanical power is assumed to be constant therefore 10 constant Fig. 11. Intersection of electrical and mechanical torque e. Load equations In general power system loads are composed of a variety of electrical devices. For resistive loads such as lighting and .
