Evaluating synchrophasor-enabled angle-based differential protection in distribution networks

The inclusion of Distributed Energy Resources (DERs) affects the protection requirements and the functional constraints of the modern distribution networks (MDNs). With continued research on the primary protection of MDNs, this paper evaluates an angle-based differential protection scheme utilizing synchrophasors from distribution-level phasor measurement units (D-PMUs). The suggested scheme is based on computing the Absolute Superimposed Differential Angle (ASDA) of positive sequence current between two ends of a distribution line. The ASDA concept is explained by considering internal and external fault conditions. The initial investigations are performed on a modified real-distribution network in the Dubai utility, assuming rotating or non-rotating DER. Thereafter, the scheme is thoroughly examined in a seven-node MDN modeled in Real-Time Simulator, exploring various scenarios such as different fault types, fault resistance and line length variations, switching transients, varying DER penetration levels and types, and different network operation modes. Additionally, the analysis of CT saturation effect, measurement noise and response time of the proposed scheme has been carried out. A real-time laboratory testbed is also developed utilizing physical PMUs and a real-time simulator to verify the performance of suggested scheme in a practical environment. Furthermore, a quantitative and qualitative evaluation of the proposed strategy is presented to demonstrate the strategy's reliability and efficacy. Our findings demonstrate that the suggested approach reliably detects short-circuit faults in abroad spectrum of network conditions.