Abstract: Short-circuit faults and disconnection faults are common line faults in the distribution network, which have an important impact on the safe and stable operation of the distribution network. Taking the ungrounded power distribution system as the object, this paper proposes a new method of integrating ceramic capacitors inside the line insulators, detecting the transient voltage signals of the distribution network line faults through the capacitive voltage divider, and then realizing the new method of power distribution line fault detection. PSCAD/EMTDC software is used to establish a simulation model of the power distribution system under short-circuit faults and disconnection faults, and the line voltage characteristics monitored by the insulator built-in capacitive voltage divider under typical fault conditions are studied. The results show that for low-resistance and medium-resistance grounding faults, the line fault phase voltage quickly decreases to a stable value, the voltage underdamped oscillation of the corresponding phase of the sound line attenuates to a stable value, and the transient high-frequency signal characteristics of the faulty line and the sound line are obvious ; For phase-to-phase short-circuit faults and single-phase disconnection (including grounding) faults, detection and identification can be performed based on the characteristics of the steady-state voltage on the load side. This shows that the method for detecting the line fault of the distribution network based on capacitive voltage divider integraded inside of insulator proposed in this paper is feasible.