Research On Optimal Configuration Of FACTS Components In Power System

The power grid in our country is being constructed and developed into a large-scale,long-distance,large-capacity and interconnected system.This trend contributes to the enhanced interconnection compactness of the regional sub-systems,also makes the transmission network structures more complex and the system operation conditions more complicated.Under the existing transmission network condition,the Flexible AC Transmission System(FACTS)can improve the reliability and stability of the power system operation by the flexible and rapid control actions.The research on FACTS has become much more popular in recent years.For the large hybrid AC/DC power grid,the effects and performances of FACTS are determined by the specific device type,the installation location,and the installed capacity.To avoid the waste of resources,it is important to study the optimal configuration of the FACTS devices.At first,it introduces the classification,structures and operating principles of the FACTS devices.The work is focused on the parallel SVC and STATCOM,the series TCSC and the hybrid series-parallel UPFC which all have been widely installed.The functional characteristics and mathematical models of these devices are analyzed respectively.Among these FACTS devices,SVC and STATCOM can improve the node voltage stability obviously,while TCSC contributes to the increased power transfer capability of transmission lines.UPFC is able to achieve these two effects simultaneously.And then,it proposes an optimization model for the optimal UPFC configuration considering the transmission loss.The proposed model is aiming at improving the security and stability of the power system,with the power flow transfer after contingency happened taken into consideration.The artificial algae algorithm is deployed to solve the optimization problem so that the installed locations and control parameters of the UPFC device are determined.In the case studies,the effectiveness of the proposed model isdemonstrated by the IEEE 14-bus system and a regional power system.It can provide a reference for the practical application of UPFC in the power system.Finally,in view of the problems faced by the Hubei power grid operation,the effects of FACTS on improving the power system voltage stability and transient stability are analyzed.The installation location,capacity and pattern(centralized or decentralized)of STATCOM are studied to examine its effect on improving the system voltage stability.The limiting point sensitivity index is proposed as the installation guidance for STATCOM,which has better performance in practice.The simulation results suggest that both STATCOM and TCSC work in improving power system stability.