Enhancement of Digital Distance Protection Scheme with Novel Transducer

Transmission Line Distance Protection Under Current Transformer Saturation

“…This condition is illustrated in Fig. 3(b), where k̇= İ′ m1 /İl due to the opposite directions of İ′ m1 andIl, and the action circle corresponding to (7) shifts to quadrant III. Therefore, distance protection may malfunction when a short-circuit fault occurs in the reverse near-end or the bus.…”

“…Thus, depending only on the optimal selection of CT locations cannot resolve these problems completely. Other studies have proposed the use of new types of CTs, such as Rogowski coils or electromagnetic current transformers (ECTs), to limit the impact of CT saturation on distance protection [7], [8]. However, these new types of CTs cannot be applied in a sufficiently extensive manner to address these problems owing to issues regarding stability and economic considerations.…”

Improving distance relay performance for heavily distorted voltage and current by accurate signal reconstruction using extended Kalman filter

“…As studied experimentally in [20], an OCT is not saturated by the dc offset current under simulated short circuit conditions and also gives acceptable performance with white noise. Rogowski Coil [21] is yet another viable substitute for CTs with better linearity, greater accuracy and extensive operating current range [22]. The merits and demerits of different compensation schemes for saturated CTs are outlined in table 1.…”