A New Method Of Single - Phase Adaptive Reclosing For EHV AC Transmission Line

Power system operating experience shows that EHV AC transmission line fault mostly as " transient" faults and single phase to ground fault type majority. To improve the stability and reliability of supply of power system operation, usually automatic reclosing technologies, and when single-phase ground fault occurs, disconnect only the faulty phase, single-phase automatic reclosing technologies. Existing automatic reclosing is blind coincidence, before closing does not judge the nature of the fault, which led to the possibility of coincidence to permanent failure. Once coincide to a permanent failure, the power system will inevitably cause secondary impact, leading to a short circuit or even more serious than the consequences, therefore, to avoid overlap to a permanent failure, the study of adaptive reclosure technology emerged.Adaptive Technology Research reclosing the most important issue and the key point is how to disconnect the circuit breaker after a fault phase to determine the nature of the fault before closing for the instantaneous fault permanent fault during this time. Principles and methods for determining the nature of the fault, in theory should take into account the criterion of reliability and rapidity, this paper on the following aspects in-depth study and exploration:First study EHV AC transmission line under transient faults and permanent faults transition from normal operation to the electromagnetic transient arc fault disappears, the dynamic characteristics of the arc from a secondary arc reignition dynamics and characteristics of secondary analysis start, build arc fault model and analyze the characteristics of arc current, recovery voltage characteristics. Research and analysis of the shunt reactors for System Recovery affect the voltage, using EMTDC/PSCAD built with shunt reactors and EHV transmission line model without a shunt reactor is simulated; research and analysis transient faults and single phase permanent fault conditions voltage characteristics disconnected phase ends, summarize existing mainstream transient faults and permanent faults voltage criterion formation theory, comparative analysis based criterion transient fault arc characteristics and voltage transient fault recovery based on each criterion the advantages and disadvantages; for the existence of lines, shunt reactors with a shunt reactors allows transmission line transient faults exist beat disappears after recovery voltage phase. Beat frequency voltage characteristics, failure secondary arc extinction time and detection methods to determine the beat frequency characteristics of research, and then raised a permanent fault on starting voltage half-cycle delay further superimposed transient fault detection and discrimination against one of its recovery methods:The recovery voltage characteristics in the case of research with shunt reactors and transmission lines without the occurrence of shunt reactor transient fault and permanent fault basis, the paper-based recovery voltage difference under different conditions is proposed based on the nature of the fault monitoring frequency recovery voltage single phase permanent fault adaptive criterion, the criterion and the criterion based on the previous recovery voltage difference is that its use of its own voltage waveform is compared with historical data, can be adaptive tuning threshold.Finally, the summary and the full text contents to be prospects for future research.