The use of DC for primary power distribution has the potential to bring significant design, cost and efficiency benefits to a range of power transmission and distribution applications. The use of active converter technologies within these networks is a key enabler for these benefits to be realised, however their integration can lead to exceptionally demanding electrical fault protection requirements, both in terms of speed and fault discrimination. This paper describes a novel fault detection method which exceeds the capability of many current protection methods in order to meet these requirements. The method utilises fundamental characteristics of the converter filter capacitance’s response to electrical system faults to estimate fault location through a measurement of fault path inductance. Crucially, the method has the capability to detect and discriminate fault location within microseconds of the fault occurring, facilitating its rapid removal from the network
