New Substation-Area Protection Method for Handling Missing Current Information in Transformer Branches

Missing measurement information in substations may cause corresponding protection systems to be blocked, leaving primary equipment operating under single protection or unprotected conditions, which significantly reduces the reliability of the protection system. To address this issue, this paper proposes a novel substation-area protection method based on the advantages of full-station measurement information sharing to handle missing current information in transformer branches. First, the normal current information is utilized to reconstruct the missing current data. The reconstructed current is then substituted for the missing current in the transformer and bus protection systems for fault judgment. If both the transformer protection and bus protection operation criteria are satisfied, a fault is identified within the abnormal information recognition zone, and a tripping command is sent to the circuit breaker at the missing measurement point. After the circuit breaker operates, the final fault location is determined using bus protection and transformer protection. Theoretical analysis and simulation verification demonstrate the effectiveness of the proposed substation-area protection method under various grid fault scenarios accompanied by missing measurement information. Additionally, the method exhibits the advantages of being unaffected by transformer inrush currents.