High-impedance faults (HIFs) on distribution feeders cannot be detected by conventional protection schemes, as HIFs are characterized by their low fault current level and waveform distortion due to the nonlinearity of the ground return path. This paper proposes a method to identify the HIFs in distribution system and isolate the faulty section, to reduce downtime. This method is based on voltage measurements along the distribution feeder and utilizes the sequence components of the voltages. Three models of high impedance faults have been considered and source side and load side breaking of the conductor have been studied in this work to capture a wide range of scenarios. The effect of neutral grounding of the source side transformer is also accounted in this study. The results show that the algorithm detects the HIFs accurately and rapidly. Thus, the faulty section can be isolated and service can be restored to the rest of the consumers.

Wide area monitoring system (WAMS) recognizes the condition, quality and stability of various parts of the power transmission network with the help of advent monitoring and measuring equipment. Phasor measurement units (PMUs) have emerged as vital devices for wide-area monitoring systems. Now a day, the optimal placement of PMUs for maintaining the observability of the whole network and providing adequate and reliable communication between them are challenging problems. A novel algorithm is proposed in this paper to identify optimal placement of PMUs by performing observability analysis with reduction in computational burden. This paper includes the optimal PMU placement algorithm and the degree of observability of each bus according to the PMU locations and its applications on IEEE 14 bus system. The simulation work has been performed on Orissa power grid network to show the effectiveness of the proposed methodology.