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，瞬变电磁法，频率域电磁法，直流电法和地震法等。
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. 介绍了用相对漏磁法推导自耦有载旁柱调压变压器电抗电压的计算方法。
