The invention relates to the field of circuit fault detection and provides a method and
system for fault positioning of a contact net. The method comprises the steps that currents and electric fields in a circuit of the contact net are sampled by a
detector; sampling values of the current and sampling values of the electric filed are sent to a communication terminal; a trigger instruction is sent to the communication terminal when the
detector detects that current changes in the contact net satisfy a first preset condition; after the communication terminal receives the trigger instruction, whether a fault takes place in the circuit of the contact net is determined according to the sampling values of the current and the sampling values of the
electric field in the contact net which are sent by the
detector; fault information is sent to monitoring equipment when the communication terminal determines that the fault takes place in the circuit of the contact net; and the monitoring equipment receives the fault information and determines an occurrence position of the fault in the contact net according to position information of the communication equipment which sends the fault information. The method and
system for the fault positioning of the contact net provided by the invention can avoid utilization of travelling
wave detection equipment so as to reduce cost; and the method and
system are only slightly influenced by differences in manufacturers, models and relevant accessory equipment of the contact net circuit, so that accuracy of the fault positioning is increased.