Based on the transmission characteristics of extra high voltage (EHV) transmission lines with shunt reactors

a new algorithm for calculating transition resistance through a distributed parameter model is presented. In view of the case of permanent fault where the transition resistance is basically fixed at a low value

whereas in the case of transient fault

where after the arc is extinguished

the calculated value of transition resistance immediately increases to a large value

we are enabled to distinguish the fault nature

and the extinction time of secondary arc as well. This method can work just by making use of the current of shunt reactors and the non-fault-phase at one terminal

and fault location results

and is easy to use. Electromagnetic transient program simulation results and analyses show that the method is hardly affected by fault location

load current and transition resistance

and can be applied to transmission lines with shunt reactors at one terminal and at both terminals. What's more

the method can withstand the inaccuracy of fault location

transmission line parameters

and system frequency to some degree. This work is supported by National Natural Science Foundation of China (No. 51107112).