Real-Time Wide-Area Disturbance Monitoring and Protection Methodology for EHV Transmission lines

Abstract

This paper presents a real-time wide-area disturbance monitoring and protection (RWADMP) methodology for the backup protection of EHV transmission lines in smart grids (SG). The proposed methodology employs harmonic phasors (1st, 2nd, and 3rd order) of 3-Φ current signals estimated using multi-phasor measurement unit (MPMU) for fault detection, classification, and discrimination of faulty line accurately. Further, the stressed condition such as load encroachment is discriminated from fault. The phasors which were estimated at MPMU are communicated to phasor data concentrator (PDC) at system protection center. MPMU is realized in hardware using NI cRIO, current sensor and GPS module in conjunction with LabVIEW software. Performance of the proposed methodology has been validated on the scale down laboratory models of 400 kV EHV transmission systems such as two-generator two-bus and two-generator three-bus systems. The experimental results show the efficacy of the proposed methodology in improving the overall reliability of the protection system. Also, the proposed methodology is less sensitive to the different fault conditions like fault resistance (FR) and fault distance (FD). Further, the user-friendly LabVIEW monitoring system enhances the visualization of the power system state in PDC. Also, it helps the grid operator to take appropriate action in case of system stressed condition and avoids the mal-operation of the protective devices.