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Summary In this paper, a communication‐based selective protective scheme using the combined adaptive cumulative sum algorithm (CACUSUM) is proposed, which can be used in wide‐area protection of multi‐terminal high voltage direct current (MT‐HVDC) transmission lines. The proposed algorithm works in the time domain and uses the variation pattern of the magnitude of line currents and bus voltages for fault detection. Simulation is done in MATLAB program using a test four terminals meshed HVDC transmission system. As a robust fault detector, the proposed approach detects fault occurrence as well as determining faulty zone, either faults on the DC line or AC part of the HVDC system; the whole in less than 2 ms. Simulation results confirm the robustness of CACUSUM performance against different fault resistances and different fault locations as well as the presence of noise in the signals. Appropriate speed, adaptivity, independence from system parameters, low sampling rate, low computational burden, simplicity, no need for any complicated hardware, and ability to detect cross faults are the significant benefits of this method in comparison with other ones. [ABSTRACT FROM AUTHOR]

The open-phase fault in vector-controlled drives is known as one of the most prevalent failures that require immediate detection. It is still challenging to develop a trustable fault diagnosis scheme at light load, transients, and low-speed regions. This paper presents a novel open-phase fault diagnosis strategy for three-phase induction motor drives over the entire speed range and for different load conditions. By taking advantage of the second-order rotational park transformation (SORP), new fault indices are proposed to identify the open-phase location without using any additional sensors or electric equipment. Comparing with root-mean-square (RMS) calculation-based methods, the proposed method detects the fault at least twice faster, with minimal system resources. The presented scheme may be implemented simply and is robust against the operating point changes. Proof of the proposed fault detection and localization method has been shown through experimental tests on a 250-W three-phase induction machine which is controlled by TI-DSP F28335. [ABSTRACT FROM AUTHOR]