| With the continuous increase in power demand,power resources have become increasingly scarce,and the energy distribution between energy distribution between provinces in my country is not matched with economic development.In order to reduce transmission loss,ultra-high voltage,long-distance,and large-capacity transmission lines are widely used.Adding series compensation devices to transmission lines has a very positive effect on the improvement of voltage quality,as well as the improvement of power system stability and line transmission capacity,However,the input of series compensation capacitors destroys the uniformity of transmission line parameters,and has many unfavorable effects on the ranging process.Therefore,when the series compensation line fails,the accurate and rapid determination of the location of the fault point has a positive effect on the later maintenance and elimination.Firstly,this paper starts from the traveling wave theory of transmission lines,discusses the phenomenon of refraction and reflection of traveling waves,the energy and attenuation law of traveling waves,analyzes the composition and working principle of the series compensation device,as well as the fault location of the series compensation transmission line.The feasibility of the traveling wave method for fault location of series-compensated transmission lines is discussed,and the fault location formula is finally determined.Secondly,at present,there have been some researches on fault location of series-compensated lines at home and abroad,but these algorithms have certain limitations.For series-compensated capacitor lines,the fault current traveling wave head is slow,and the detection of the traveling wave head is difficult.When the fault traveling wave signal When there is large noise in the fault,the traditional fault feature extraction method cannot accurately extract the characteristic signal of the fault traveling wave.This paper proposes a fault based on Whale Optimization Algorithm(WOA)for Variational Mode Decomposition(VMD)optimization.Traveling wave feature extraction method,this method uses the maximum kurtosis criterion to continuously optimize the objective function of WOA,so as to select more appropriate modal quantities and penalty factor values in VMD,avoiding the need to manually set modal quantities and penalty factor values.Fault location error caused by insufficient or excessive decomposition of fault traveling wave signal by VMD.The energy mutation point of the best IMF component after VMD decomposition is extracted by the Symmetric Differential Energy Operator(SDEO),and the fault location is realized by combining with the double-ended traveling wave ranging method.Compared with the traditional fault feature extraction method,the superiority of this method is verified.Finally,the simulation results show that the proposed method can realize the fault location of series-compensated transmission lines,with high location accuracy,and is not affected by the fault type and transition resistance. |
