Insulation state detection is an important method to discover potential failures of power equipment and maintain the safe operation of the power grid. However

due to the complexity and the large scale of the distribution network

traditional online monitoring schemes are difficult to implement. In order to sense the insulation status of power distribution equipment and pre-warn the faults

this paper proposes a distributed wireless sensor network（WSN） based on the Internet of Things（IoT） technology and demonstrates its feasibility. In this paper

the top-level design of the architecture of the wireless sensor network is firstly researched

then the design of data communication and sensor nodes are studied according to the requirements of economics

low power consumption

and security. Next

wireless sensor networks are adopted to conduct the partial discharge monitoring on high/compact distribution switchgeasr and low density/loose distribution cables（accessories） so as to realize the design of transient earth voltage（TEV） and high-frequency current（HFCT） sensor nodes based on LPWAN-based data transmission and management

measurement and evaluation of node energy consumption and battery life. Finally

the evaluation of equipment insulation status and pre-warning strategies which are applicable to wireless sensor networks are discussed. The research and exploration of this method are expected to provide references for more distribution network condition monitoring applications based on IoT.