Assessing Method of Voltage Sag Frequency Caused by Transmission Line faults

Fault location on transmission line influences the characteristics of voltage sag at given bus. It is difficult to determine the fault pattern and voltage sag frequency. A new method based on maximum entropy principle was proposed to assess sag frequency synthetically considered different fault types and objective probability distribution of fault location in the power system. The faulty line intervals were derived from analytical approach and sample data moments were used as constraint conditions. The probability value of fault location was determined by maximizing the entropy function. The voltage sag frequency was calculated using the proposed method. Applied in IEEE 30-bus reliability test system, simulation results show that the method is veracious and practical.