Research On Secondary Voltage Control Of Power System With Wind Power Integration

The hierarchical voltage control proposed by EDF in France has been applied in many countries,and achieved satisfactory voltage control effect.With the development of power system,the connections among the power supply areas become closer,which leads to a larger voltage control scale and increases the control complexity.At the same time,the large-scale integration of renewable energy such as wind power make the system state fluctuate frequently,which brings grim challenges to the implement of the traditional hierarchical voltage control and makes the control effect of the traditional one difficult to meet the requirements.The decomposition and coordination mechanism of partitioning control and pilot nodes control in traditional hierarchical voltage control mode is still an effective technique to solve the voltage control problems in the new situation.Partitioning control is consistent with the electrical characteristics of that reactive power is suitable for the nearest balance,and it can reduce the control scale availably.Meanwhile,pilot nodes can restrict the voltage control dimension efficaciously.However,with the new situation of wind power large-scale integration,it is necessary to seek the new models to implement and new methods to accomplish voltage control partition and pilot nodes selection to adapt to the changing opeartional state.For this purpose,this paper studies the problems of voltage control partitioning and pilot nodes selection in large power system with large scale integration of wind power,and finally proposes a modified voltage control mode and the corresponding control strategy to improve voltage control effect in large power system under the new situation.This paper gives emphasis to study the method of voltage control partitioning and pilot nodes selection for large power system under the new situation.Aiming at the problem of partitioning,firstly,a new electrical distance definition method is proposed to consider the influence of wind power integration,and then the partition of PQ nodes in whole network can be completed based on the advanced clustering algorithms introduced which can determine the number of partitions objectively.Secondly,partition of PV nodes can be accomplished through the definition of PV nodes' area voltage control sensitivity.And finally,according to the requirements of reactive power voltage control partition define the evaluation index respectively to quantify the partition resulted in all aspect.Contraposing the problem of pilot nodes selection in new situation,this paper considers adopting pilot nodes dynamic updating to cope with the influence of wind power integration.Toward this end,the proposed method use each partition resulted as the pilot nodes selection domain to obtain the pilot nodes from the perspective of clustering,which can break the computation limitations of traditional large-scale optimization based on a newer fast clustering algorithm introduced,in addition,the clustering eigenvector can be quickly formed through sensitivity calculation.Those measures proposed above can reduce the pilot nodes selection time positively to realize the quick selection of the pilot nodes.Based on the voltage control partition and pilot nodes quick selection method proposed,this paper modifies voltage control mode.The pilot nodes dynamic adjustment at the start of the the tertiary voltage control period will be implemented,the objective function and coresponding constraint condition in the period should be updated dynamicly,which can make the voltage control target follow the change of system operatitional state and ensuring a real-time better voltage control effect.The proposed method of partitioning and pilot nodes qucik selection can effectively solve the influence of wind power large-scale integration,the modified hierarchical voltage control mode designed based on this can improve the voltage control effect observably to decrease the power system loss,which can be a provide a supplementary reference for the voltage control of large power system in the new situation.