Frequency Model of Generator Considering Thermal Constraint and AGC Regulation

In this paper, a novel equivalent model considering the thermal constraint and AGC regulation is proposed for analyzing the frequency of thermal units. The UHVDC converter station blocking is very sensitive to frequency fluctuations in a bulk power system, so an accurate and easy-to-use model is much desired for the operation decision and control design. Firstly, actual output characteristics of the thermal unit are presented. Secondly, the structure of an equivalent frequency model is put forward to describe these characteristics. Thirdly, the scheme of estimating model parameters is offered to ensure to make the responses fit with the measured data. Fourthly, CEPRI-36 system is adopted to verify the proposed model. Finally, simulation precise is manifested by an actual case in East China Power Grid. The proposed model shows significant advantages on high accuracy and clear mechanism. In addition, the main feature of governor and generator is reserved, which is sufficient for analyzing the impacts of system disturbances on the frequency. Considering the increasing installation of UHVDC in power systems, this novel model is extremely beneficial to situational awareness and control decision in operation rooms.