Research On Security Evaluation Of Plant Power System In Start-up Of Pumped Storage Unit

With the rapid development of power industry,the pumped storage power station plays an irreplaceable and important role in the power system due to its advantages of peak regulation,frequency modulation and emergency reserve,its development is closely linked with the national economy.The security of power system in pumped storage power station is related to the safe and reliable operation of the unit and the whole power station.However,from the operating experience,especially in the start-up process of pumped storage unit,the power system internal anomalies and failures occur occasionally.Security evaluation of plant power system is different from the traditional power grid.At present,there is no comprehensive optimization scheme and usually no effective security evaluation for plant power system in start-up process of unit.Therefore,it is of great significance to study the security evaluation method for plant power system in start-up of unit.In this paper,the principle of the typical starting mode of the pumped storage power station and its influence on the plant power system are analyzed in detail.Through the theoretical research and simulation analysis,it is put forward that the power quality index of plant power system based on voltage drop and harmonic content of main power bus in the process of the unit starting.Through the relevant analysis and research on the field of security evaluation,this paper proposes a method suitable for plant power system during the unit starting process,which is gray clustering evaluation method based on the central point triangle whitening weight function.This evaluation method puts forward the concept of safety level of the plant power system,taking the unit different starting sequence as the objects of evaluation,taking the power quality of the power supply system bus in the unit starting process as evaluation index,finally forming a set of security evaluation scheme for the plant power system with universal applicability.In this paper,taking bailianhe pumped storage power station as an example,the safety level of its plant power system is analyzed qualitatively at first.Then,according to the security evaluation scheme for the plant power system,the evaluation of the power quality level of its power system main power bus is carried out.The evaluation results are in line with the actual safety level,which proves the accuracy and practicability of the security evaluation scheme.Through the analysis of the evaluation results,we can get the regular conclusion and the root cause of the different security of its plant power system under different wiring modes.Finally,aiming at the power quality problems of plant power system in start-up of unit,combined with the evaluation results of the bailianhe plant power system,the three measures of harmonic control,plant power distribution and starting mode innovation are put forward to improve the safety and reliability of power system in pumped storage power station.Among them,asynchronous starting method based on dynamic reactive power compensation can effectively improve the power quality of the plant power system,and play the regulating role of pumped storage station on the power system.