The techniques adopted include magnetic method, gravity, transient electromagnetic method, frequency domain electromagnetic method, direct current method and seismic method. 其中包括磁法，重力，瞬變電磁法，頻率域電磁法，直流電法和地震法等。
A caculation method of deriving the reactance voltage of auto-transformer with on-load voltage regulation at side-yoke is introduced by using relative magnetic leakage method. 介紹了用相對漏磁法推導自耦有載旁柱調壓變壓器電抗電壓的計算方法。
