Probabilistic identification method of distance protection misoperation due to power flow transfer

Abstract

The unintended trip (misoperation) of backup protections caused by overload scenarios or improper relay settings may trigger or accelerate cascading accidents and blackouts. Previous researches on the misoperation identification of the backup protection, focusing around deterministic methods rather than probabilistic information, usually initiates the decision making after the final formation of flow transfer and leaves out the dynamic process of relays after the system fault. Time for taking measures is hence very limited, especially when the communication latency and the calculation task are considered. A new probabilistic identification method of the distance protection misoperation considering the sequential coordination of backup relays is proposed. Then the preliminary implementation architecture of the proposed method is presented, which considers the coordination of computing task allocation, and the information forming and update strategies to make full use of existing protective devices and decrease the communication load. Case studies demonstrate that the method could adapt to different scenarios and identify the potential misoperation reasonably to allow time for taking measures against protection malfunction. Furthermore, it could supply compact reference information for fault review and analysis.

Improved zone-3 distance protection based on adjacent relays data

“…In addition, the large reaching of zone‐3 makes it vulnerable to mal‐operation during the stressed system conditions such as power swings, load encroachment, and voltage decline which could expose transmission lines to cascading outages. The effects of zone‐3 mal‐operation in recent blackouts are studied in the literatures with presenting some solutions to mitigate them. Therefore, improving the performance of zone‐3 for correct operation during stresses and also decreasing its operation time are of great importance.…”

“…The effects of zone-3 mal-operation in recent blackouts are studied in the literatures [1][2][3][4][5] with presenting some solutions to mitigate them. Therefore, improving the performance of zone-3 for correct operation during stresses and also decreasing its operation time are of great importance.…”