Abstract: In the existing ultrasonic positioning method of partial discharge for switchgear cabinet and other electrical equipment, time difference of arrival (TDOA) method has been widely used due to the advantage in positioning accuracy and technical implementation. Considering that the time delay estimation algorithm plays a leading role in the whole positioning system, the basic correlation, generalized correlation, quadratic correlation and other time delay estimation algorithms are analyzed in this paper. Then, based on the quadratic correlation, a new method, named the generalized cubic correlation time delay estimation method is presented by performing once more correlation again with new designed weighting functions. Finally, an experimental platform of switch cabinet is built to test the above methods and make comparative analyses. The performances of various algorithms are analyzed and compared. The results show that the generalized cubic correlation time delay estimation method has better advantages and better antinoise performance than other algorithms in relatively strong noise environment.