An Efficient and Generalized Algorithm for Calculating the Earth Return Impedance With Pollaczek Integral Using the Moment Technique

An efficient and generalized algorithm is proposed to calculate the earth return impedance expressed by the Pollaczek integral. The nonoscillatory part of the integrand without the cosine function is approximated using a number of piecewise quadratic functions, and the Pollaczek integral can be expressed in a closed form with the help of the moment functions. The numerical examples validate the proposed algorithm by comparing with the results calculated using the formulations in other published works. The proposed algorithm is efficient and its computational time is almost irrelevant with the variant parameters in the Pollaczek integral.