A novel line parameter adaptive phasor domain fault location method for double-circuit transmission lines

Abstract

• Accurate phasor domain fault location for double-circuit transmission line. • Fault location without acquiring information of line parameters. • Uniqueness and convergence of the fault location equation solution. Phasor domain methods had been commonly used in power transmission line fault location. To improve the accuracy and line parameter adaptive ability of phasor domain fault location, this paper studies a two-terminal phasor domain line parameter adaptive fault location method. First, this paper analyses the convergence issue of original multi-dimensional non-linear fault location equations. Then, by regarding the four complexes consist of fault distance and line parameters as the new unknowns and thereby supplementing a constraint equation about the new unknowns, a quadratic fault location equation set is reconstructed. Furthermore, it is mathematically proven that the four new unknowns are all within the first quadrant. Therefore, the elements in the Jacobian matrix of the reconstructed equation set are all proven to be of symbolic invariance within the solution space. Thus, by using Newton-Raphson method and setting the initial iteration value of the four unknowns to any complexes within the first quadrant, the iteration solution of the reconstructed equation set will converge to the true solution. Finally, electro-magnetic fault simulations are used to evaluate the proposed method. The test results demonstrate that the proposed method is able to guarantee fault location accuracy under different circumstances without knowing line parameters.