Search

• Polarity of Slope of instantaneous current increment is mathematically estimated for directional protection of series compensated line. • Internal faults are distinguished very quickly from external events during power swing. • Proposed scheme is suitable for high level of series compensation. • Its performance is not affected by high fault resistance, synchronization error and current transformer (CT) saturation. • It is fast and more reliable compared to existing incremental quantity-based methods. Existing protection schemes for series-compensated transmission line (SCTL) lack either in reliability or speed during power swing (PS). A new ultra-fast reliable method is proposed in the present article using the slope of instantaneous current increment (SICI). The peaks of SICI (denoted by PKS) of a modal component of currents above a dynamic threshold are obtained to detect the sudden jump in SICI , which occurs after a transient disturbance. PKS of two terminal-currents are of same polarity for a fault within SCTL but they are of opposite polarity for any external event. This unique characteristic is mathematically verified and exploited to discern internal faults from external events during PS. Proposed method is found unaffected for high level of series compensation, position of compensation, close-in fault, fault inception point, high fault resistance, synchronization error and CT saturation. The results are finally compared to the incremental quantity-based methods to justify its merit. [ABSTRACT FROM AUTHOR]

• A new method is introduced to improve the one way distance (OWD) algorithm. • An improved OWD algorithm is used to identify internal and external faults. • The ratio of nonsimultaneous points is proposed to enhance the protection security. • To reduce the impact of CT saturation, the virtual clamped current is proposed. • The results show that the performance of the proposed protection is satisfactory. In terms of integrating large-scale wind farms into power systems, the fault characteristics of power systems have undergone fundamental changes, potentially leading to the rejection and misoperation of traditional protections. To address these issues, a time-domain pilot protection based on trajectory distance characteristics is proposed. A novel trajectory distance calculation method is introduced to improve the one-way distance (OWD) algorithm, which is used as a metric to quantify the distance between current trajectories to identify internal and external faults. To overcome the adverse impact of nonideal conditions, a metric, namely the ratio of nonsimultaneous points is proposed. Faults are identified using two metrics. Validation results from PSCAD/EMTDC and hardware-in-the-loop platform demonstrate that the proposed protection can operate within 15 ms in most cases and has excellent robustness against diverse nonideal conditions, including tolerating noise with 10 dB signal-to-noise ratio. Moreover, it considerably outperforms traditional and new differential protection methods. [ABSTRACT FROM AUTHOR]