A Fast Single-Ended Protection Scheme for DC Distribution Networks

Emerging technologies in decentralized solar power generation and electric vehicle infrastructure present an optimistic perspective for flexible DC distribution networks. During the fault, the current in the line increases rapidly and quickly reaches the maximum current that the DC circuit breaker can interrupt. Therefore, the reliable operation of DC distribution networks heavily relies on a fast fault detection method. This paper utilizes magnetic rings as line boundaries and proposes a fast single-end protection method in the frequency domain. First, the characteristics of transient voltage under the influence of magnetic rings are analyzed. Next, based on these voltage characteristics, a protection criterion using the ratio of high-frequency (HF) to low-frequency (LF) energy is proposed, along with a complete protection scheme. Numerical simulations validate that faults can be recognized quickly and accurately by the proposed method.