Assessment Of Primary Frequency Control Performance For Thermal Power Generation Units

The performance of primary frequency control(PFC)in power generation units is paramount important for power grids to suppress frequency fluctuations and preserve load-generation balance.Mastering the performance of PFC for thermal power units is a major demand for the rapid development of the grid which can improve the dynamic adjustment ability and ensure the safe and stable operations.However,which results the traditional method based on the unit step response test cannot be satisfied.This paper conducts a study to evaluate the performance of primary frequency control from the daily operation data of thermal power units,it includes the selection method of PFC data segments,the estimation method of primary frequency control deadband and the evaluation method of primary frequency control performance based on trend extraction.It mainly includes the following contents:1.The selection method of PFC data segments:according to the characteristics of primary frequency control response for thermal power generation units,it is determined whether the data segment contains a complete primary frequency control process through the state,duration and size of turbine speed before the change.The primary frequency control data segments are obtained from the daily operation data,as the basis to evaluate the primary frequency control performance.2.Deadband assessment method of PFC based on static characteristics:First,the steam turbine speed difference and the actual power difference are reordered according to the frequency modulation static characteristic relationship to obtain the correlation sequence.Then,each group of correlation sequences are combined to obtain the correlation domain,and the correlation domain is constructed into a scatter domain.Finally,the deadband of primary frequency control is estimated from the static characteristic curve.3.Performance assessment method of PFC based on trend extraction:The proposed method is composed by three steps.In the first step,the data segments containing primary frequency control responses are found according three required characteristics.In the second step,PLRs are obtained for the selected segments of generated active power.In the third step,the response stage is formulated based on the Piece-wise linear representation(PLR)results,and the primary frequency control performance of each data segments is estimated according to its definition.Numerical and industrial examples are provided to prove the correctness of the proposed methods.Industrial examples include the step response test examples and the actual response examples in daily operation of PFC for power generation units.The results show that methods proposed in this paper can correctly evaluate the performance of primary frequency control for thermal power units and verify the effectiveness of the proposed methods.