Power Grid Reliability Evaluation Incorporating Facts And Optimal Allocation Model Research

This dissertation is supported by National Natural Science Foundation ofChina(50977094).By means of regulating power grid parameters flexibly, FACTS devices provide anew method for optimizing grid tide distribution in additional to unit rescheduling andnetwork topology change, bring about a new opportunity for the full mining existingtransmission equipment potential and reduce the power network operation risk. Based oncomposite generation and transmission system reliability assessment, after discussing thereliability improve effect of FACTS devices adequately, a heuristic FACTS optimalallocation algorithm is presented in this paper, the details are as following:1) According to power flow calculation incorporating FACTS regulating functionneed to change system node admittance matrix elements, even produce variable elementsin the matrix, the contribution of control parameters of FACTS branch to grid tide isequivalent to power injection of the corresponding branch. Thus, power flow calculationand optimal power flow calculation can be executed conveniently without modify theoriginal node admittance matrix.2) Based on the power injection model of FACTS, influence of FACTS regulatingon power flow equation, branch power flow and optimal load shedding is analyzedexhaustively, then an universal optimal load shedding and composite generation andtransmission system reliability assessment model considering FACTS are constructed.Using the state enumeration method, composite generation and transmission systemreliability assessment is executed on RBTS and IEEE-RTS79systems. In order toproviding beneficial reference information for optimize allocation of FACTS, influenceof a series of factors, such as FACTS installation position，installed capacity, systeminstalled capacity， system load level, transmission line reliability parameters，FACTSreliability parameters, on FACTS devices’ system reliability improve effect is analyzed.3) Considering the computational complexity of generation and transmission systemreliability assessment, a heuristic FACTS optimal allocation algorithm based on thecapacity of sensitivity is presented. In this algorithm, utilizing the physical meaning ofLagrange multipliers of control parameters in the inequality constraints of FACTS, thefirst order sensitivity of EENS with respect to the capacity of FACTS is deduced,according to the sorting of the sensitivity indices a method to determine the optimal installation site of FACTS is proposed; considering the investment cost and customerinterruption cost, the optimal installation capacity of FACTS is determined by means ofincreasing the installed capacity continuously. Simulation result of RBTS andIEEE-RTS79systems show the algorithm has good convergence and strong general, cannot only greatly reduce the overall amount of calculation of configuration but alsoguiding engineering practice.