Study About Single-pole Adaptive Reclosure Of Transmission Based On Entropy

Transmission line will act automatically re-closing in the event of ground fault,but if the circuit breaks reclosing in the coincidence that fault is permanent, thepower systems and power equipments will be impact of the secondary fault current.In Present adaptive reclosing technique which can determine the type of failure afterfailure occurs then re-closing has been applied in the transmission lines. Thetechnical points of adaptive reclosing are correctly and timely used to determine thefault type. In this paper, we used EMD decomposition and Sample Entropy theoryto analyze the properties of transmission line single-phase ground fault, and thenachieve the right judge to fault type to ensure the successful implementation ofadaptive single-phase reclosing.The principle is based on the analysis summarizes single-phase ground faultcharacteristics and the most commonly used adaptive reclosing. This paper usesMATLAB simulation software, and respectively simulates the transient andpermanent single-phase ground faults. We make analysis of the fault phase voltageof the single-phase arc fault which is based upon the transient and permanentsimulations.Secondly, depending on the nature of the failure of the different effects of faultphase voltage this paper proposes methods that are based on EMD and the entroy.Using empirical mode decomposition to decompose the simulated fault phasevoltage, this paper can get the approximation narrow-band signal of intrinsic modefunctions from the complex non-linear original signals. As both the approximateentropy and the sample entropy have the good characterizations that can expressesthe complexity of the signal as the specific number and be not sensitive to noise,this paper caculates the approximate and sample entropy values of the IMFcomponents. By comparing the differences of fault phase voltage transient partsignal entropy value, we can better identify transient fault and permanent fault. Finally, two methods in this paper were compared quantitatively, as thealgorithm of sample entropy and approximate entropy are different. The sampleentropy is not sensitive to the length of signal sequence and the loss of information.So the sample entropy has greater interval to determine the fault type. Then acomparison is taken between approximate entropy, then we obtain that theinformation entropy method can derive from the limit of different faultconditions.And through the transmission line ground fault simulation for situationssuch as different fault points, different grounding resistance and whether shuntreactors, we verify the correctness and validity of the method in this paper underdifferent fault conditions.The paper summarizes and analyzes the need to further improve the work.