| With the goal of "carbon peaking" and "carbon neutral",the proportion of renewable energy power installed in China’s power system will continue to increase.Meanwhile,the increasing capacity of Ultra-high voltage AC/DC transmission not only increases the risk of frequency disturbance,but also significantly reduces the frequency stability of the system after the disturbance.To this end,this paper proposes a primary frequency regulation reserve optimization method for power systems considering the active regulation characteristics of heterogeneous power sources,aiming to improve the frequency stability of renewable energy high percentage power grids in extreme events,with the following main work:(1)A renewable energy power system frequency time domain analytical model considering the active regulation characteristics is proposed:based on the classical SFR model framework,the system frequency time domain analytical model considering multi-damping is proposed from the perspective of analytical derivation;on the basis of the multi-damping model,two linear expressions are made for the nonlinear link of the governor,and the analytical derivation is carried out by the non-zero initial state analysis method to obtain the system frequency time domain analytical model considering the dead zone of the governor,the frequency time domain analytical model of the system considering the dead zone and limiting amplitude.Finally,the accuracy and necessity of the proposed model are verified through design experiments and simulations,and the sensitivity of the nonlinear link of the governor to the disturbance power is discussed.(2)A(primary frequency regulation,PFR)reserve procurement model for renewable energy power system considering the governor characteristics is proposed:based on the system frequency time domain analytical model considering the governor limit,its frequency nadir expression is transformed into a frequency nadir constraint,and then a hyperplane fitting linearization method of frequency reserve constraint is proposed to transform the frequency nadir constraint into a linear expression of key PFR parameters.Then a PFR reserve procurement model of the renewable energy power system is established with the objective of minimizing the system operation cost and the constraint of steady-state operation of the power system.The model ensures the frequency stability of the system under extreme disturbances and reduces the conservativeness of the forced governor being in a linear state compared to the existing work.(3)A robust optimization method for PFR reserve of renewable energy power system considering the uncertainty of scenic power generation is proposed:starting from the PFR reserve procurement model of renewable energy power system considering the limiting characteristics of the governor,the impact of the uncertainty of scenic power generation on PFR reserve is considered,and the problem is further divided into the PFR reserve procurement main problem and the PFR reserve adequacy check subproblem,and the C&CG algorithm to solve the constructed model.Finally,the experiments are designed to show that the PFR reserve solved by the proposed model is still sufficient to ensure the frequency stability of the system in extreme events under the extreme scenarios of wind power generation.To sum up,this paper proposes a primary frequency regulation standby optimization method for power systems considering the active regulation characteristics of heterogeneous power sources,which provides a general method in the analytical calculation of frequency response of renewable energy power system,linearization of frequency stability constraint,primary frequency standby adjustment,etc.,and also provides new ideas in the subsequent consideration of the impact of uncertainty of scenic power generation on the frequency standby,which is conducive to improving the response capability of power system to extreme events and improving the frequency stability of the system. |
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