Analysis And Adjustment Of Closed-loop Operation In Complex Distribution Network

In the power system, distribution network is connected directly to Power user,and Grid and user is very concern with its reliability. When distribution networkneed overhaul or have line fault, the closing loop operation can achieveuninterrupted transfer load, but the closing loop operation of distribution networkwill generate large steady-state current and surge current, which will directly affectsthe system safety and stability.This paper introduces the concepts and patterns of closing loop operation ofdistribution network, as well as the reasons of generating loop current, and explainsthe prerequisites when need to carry out the closing loop operation.Calculating the loop current is Prerequisites for the closing loop operation,therefore, the paper establish a reduced model of the closing loop operation throughnetwork equivalent, and acquire the expression for steady-state current and surgecurrent calculation. Based on the research, the paper analyzes the main factorswhich influence loop current by mathematical expressions. Meanwhile, we simulatethe closing loop operation of a Grid by PSASP, and verify the impact of voltageamplitude and phase angle difference to loop current. Moreover, the paper gives thejudgment conditions of the closing loop operation can safely execution. Furthermorethe paper proposes the adjustment measures to reduce the loop current, analysis itssensitivity and verify its practical effect by simulation.Finally, the paper analyzes the problem of loop current exceed the allottedamount at a Grid, and present the corresponding adjustment measures, which willhas a positive influence on economic and social benefit of the Grid.