That is described as below.

 

(1) By laying ZCTs for two feeders having different loads, detected by one earth fault directional relay.

     In this case, it is inapplicable.

(2) Because of cables capacity having the same load, two cables are selected and detected by one earth fault directional relay by laying ZCTs respectively.

     In this case, two cables should be passed together to ZCT with a large diameter wherever possible.