Fault Location Method in Resonant Grounded Networks Based on Distributed Modulation and Compensation Adjustment

This paper proposes a novel ground-fault location method in resonant grounded systems based on distributed modulation and compensation adjustment. After the permanent single-phase ground fault arc has been suppressed, the Petersen coil will be adjusted to make the zero-sequence currents at the upstream monitoring points of the fault point exceed a certain threshold and be modulated in situ. At this time, the corresponding modulated signals can be extracted from the neutral-to-earth voltage on the busbar for measuring these zero-sequence currents. Taking the carrier-frequency of every monitoring point as its identification tags and the variation characteristic of the zero-sequence currents along feeders as another detection criterion, the fault point can be determined online accurately without a high-performance real-time monitoring network. In this paper, the carrier-frequencies allocation and signal conditioning scheme are proposed for a good detection accuracy of the zero-sequence currents, then the signal detection principle with the control of Petersen coil is described in detail. Simulations and experiments verified the feasibility of the proposed fault location method.