Research Of Power Grid Voltage Control Based On STATCOM

With economic development,various power loadwhich will causeincreasesof powergridlossand the reactive power losses, and the fluctuationof powergrid voltage swarm intomarket.At the same time, when transformer whichcontains impedance itselfproduce pressuredrop with thechanging of demand-side load,a wide range of voltage will be generatedat the time of continuous transmission of systempower. when the problems of voltage fluctuationsare resolved,the use of reactivepower compensation on the spotcan reduce powerlossduring transmission and reactive power compensation, which is rightandproper,is particularly important for power transmission.Becausestatic synchronous compensator reactive which is the core of flexible Ac transmission system have more advantages than other compensation deviceon control voltage stability, it is widely applied to power systems for reactive power compensation.In this paper combining research purposes and theoretical research of static synchronous compensator of works, themathematicalmodel of three-phase static ABC coordinate transformation and two-phase rotating DQ coordinate system are built and a control system used two-phase rotating dq coordinate mathematical model as a research focus is designed.The control system structure adoptsa formof negative feedback controlbased on the use of voltage and current. After achieving a feedforward compensation decoupling control and the designof control parameters combined with engineering design methods which is based on a thinking of vector control,a control scheme is applied to improve the grid voltage stabilityfor system uncertainty.In engineering practice,conventional PID control method which is used widely, setthe initial value of the PID parameterbefore the system work is ran,but when it cannot adjust the PID parameters in real time with the external system changes.Therefore,in this paper, the fuzzy control theory methodbased on the conventional PI controlis introduced to command the STATCOM for the three-phase short circuit of grid. Through the control strategy it can issue reactive power or absorb reactive powerreal-time to controlpublic node voltage stability of system in the vicinity of a given value. Additionally simulation model was constructed based MATLAB simulation softwareand a new fuzzy PID controller which notonly has the accuracy of the conventional PID control performance,also hasstrong robustness and flexibility of fuzzy control. In this issue aiming at the mutationof system structure,The system of public node voltage at the fuzzy PI control can be stable and fast to stay in the vicinity of a given value Finally, use MATLAB/Simulink to simulation system. And draw the waveform of reactive power compensation and the waveform of shock load node voltage. And compare the performance of the system using fuzzy PI controllers and traditional PI controller.The validation of correctness of mathematical models and simulation models, control strategies and controlparameters design,is completedthrough simulation studies.The controller based on fuzzy PI can modify PI parameters of dynamical and online, and make the PI of the final valuechangeWith the change of external system, so it can stabilizevoltage of system common node.Additionally,combined with simulation results,power system voltage stability is improved by the reactive compensation devices...