Fault Analysis And Fault Location Of Transient Fault On Multi-parallel Transmission Lines On Same Tower

Multi-parallel transmission lines on the same tower can enhance the capability, raise theutilization rate of land and reduce the cost of power construction. Hence it must be thedevelopment trend of the high voltage bulk transmission grid construction in China. Faultanalyses and fault location technique is the basic of the safe, reliable and economic operationof net work. For the complicate coupling of multi-transmission lines, it is more difficult forthe fault analyses and fault location. Because transmission lines are subject to fault, most ofthem are temporary faults. It is more difficult to search for the fault point. In order to solve theproblems of fault analyses and fault location particularly temporary faults ofmulti-transmission lines on the same tower, the decoupling methods, preposing low bandfilter, fault analyses and fault location method for temporary faults are deeply investigated,and a series of noval theories are presented.To solve the complicated coupling, this dissertation analysed the decoupling method ofmulti-transmission lines on the same tower. The translation matrix for frequency domain andtime domain is proposed for the theoretical bases of fault analysis of multi-transmission lineson the same tower.In order to eliminate the aliased distortion of high-frequency component, to enhance theprecision of the sampling, the hybrid parallel active filter is considered as an effective methodfor the dynamic suppression of power system harmonic. However, the hybrid active filtersystem is sensitivity to the delay control and difficult to compensate completely the harmoniccurrent of nonlinear load. In this paper, a hybrid active filter with grey prediction controller isproposed for the harmonic compensation. The grey prediction control strategies as well as theharmonic detection are analyzed, and current hysteresis comparison control method isdeveloped. A simulation model of hybrid active filter based on EMTDC is presented. Thesimulation results show that the PHAPF with grey prediction controller gives a satisfactoryperformance in harmonic and reactive power compensation.In order to eliminate the effects of transmission line coupling and parameter uncertaintyfor fault location, this paper proposed a decoupling method of four-parallel transmission lineson the same tower, then constructed the parameters self-adaptive uniformity componentequation and fault location circulation component equation. As the established equations arelinear, the proposed method has advantages of high computing speed and high precision.Using ATP-EMTP, the four-parallel transmission lines model is constructed for simulation.And the analysis results demonstrated that the proposed fault location scheme is high efficient and accurate.To find out the fault characteristics of temporary faults at the transmission lines, theexisting arc models are analysed in the dissertation. And the Mayr arc model is used toconstruct the arc fault simulation model of transmission lines. Based on the arc fault model,the transient fault characteristics are analysed. Then, the assessment method is proposed todifferentiate the temporary fault and permanent fault, laying foundation for the fault locationof temporary fault of transmission lines.To resolve the fault location problems of temporary faults at the transmission lines. Thetransient voltage characteristics of temporary faults provide a new way to deal with the singleterminal fault location method. Based on the Mayr arc model, this paper analyzes the transientcharacteristics of arc grounding fault and proposes the similarity of square wave for arcgrounding fault. Then, based on the Bergeron transmission line time domain equations, thispaper constructs the time domain equations of voltage along a transmission line based onsingle terminal data. Combined with the proposed similarity of square wave method, thesingle terminal time domain fault location method for arc grounding fault is proposed. Finally,based on the ATP/EMTP, the transmission line fault simulation model is constructed. And alarge amount of simulation is used to verify the proposed fault location method.