Study On Flexible Power Flow Of Power System Containing HVDC And FACTS

Power flow calculation is a basic content of power system analysis. Conventional power flow needs to classify the nodes and its calculation procedure and results are not very consistent with the actual power system engineering. Flexible power flow can readily overcome these shortcomings. Power flow calculation of hybrid power system containing HVDC and FACTS has the same shortcomings. And therefore it is necessary that flexible power flow should be extended to hybrid power system.This thesis is mainly devoted to the establishment of flexible power flow model of hybrid power system containing HVDC and FACTS, the deduction of the correction equations of unified iterative method and equivalent power method for flexible power flow and example verification. Major achievements are as follows.Considering the static characteristics of the generators and loads, combined with the steady state models of HVDC, SVC and STATCOM, the flexible power flow equations of hybrid power system containing HVDC and FACTS are built. In the flexible flow equations, the static characteristics of SVC and STATCOM are taken into account. In this way, the voltages of the high voltage buses controlled by SVC and STATCOM also participate in the iterations and their values are not constant values during power flow calculation. This processing method is more congruous with the actual engineering.Solving AC power system and DC power system together, the fast decoupled correction equations of unified iterative method for flexible power flow of hybrid power system are deduced, and then the calculation process of the method is given. In order to simplify the correction equations and improve the computing efficiency of flexible power flow, based on the analytic solutions of the DC equations, DC power system variables are eliminated from the power flow equations and flexible power flow calculation of hybrid power system is transformed into flexible power flow calculation of AC power system with the same number of nodes to hybrid power system. The fast decoupled correction equations of equivalent power method for flexible power flow of hybrid power system are deduced, and then the calculation process of the method is given.Combined with the actual situation of frequency regulation and voltage regulation of power system, the secondary power flow algorithm of power system is given for the purpose of more realistic simulation of frequency regulation process and voltage regulation process. The unified iterative method and the equivalent power method are used to compute the New England 10-generator 39-node hybrid power system modified, respectively. The computing results validate the effectiveness of the proposed flexible power flow model and algorithm. The comparative analysis of the primary and quadratic power flow calculation results is given under these two methods. The results indicate that the secondary power flow has more advantages in flexible power flow calculation. The comprehensive performances of the unified iterative method and equivalent power method are compared. The results show that the equivalent power method has faster computing speed and has bigger advantages and wider application prospects.