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This paper proposes a light, flexible, and yet reliable multiparametric estimation algorithm for grid-connected voltage-source-converter-based systems. This approach combines the nonlinear least squares (NLSQ) fitting algorithm and the steady-state extended harmonic domain (EHD) model to take into account the harmonic effects. The EHD model is used to take advantage of the harmonic content of the electrical signals to provide robustness and improved performance to the NLSQ estimation methodology. In addition, this harmonic formulation reduces the necessity of synchronized measurements. Details of the implementation are provided by an experimental case study, in which the grid equivalent (Thevenin voltage, inductance, and resistance), the ac-side filter (inductance and resistance), and the converter switching and conduction loss resistance are accurately estimated for three different operating conditions. [ABSTRACT FROM AUTHOR]

The identification of coherent areas is an important step to fortify the power system against the potential spread of cascading failures. This processing task helps to establish the preliminary strategies to implement online control methodologies that increase the power system reliability. In this regards, a methodology to identify coherent areas based on sliding power spectral density algorithm is presented in this paper. A coherency index is estimated from self- and cross-power spectral densities information in order to identify the coherent areas for a specific frequency related to an inter-area oscillation mode. In order to facilitate and automatize the process, an identification criterion based in the coherency index is proposed. This enables the proposed approach to be applied offline or online. In addition, the computation of the self-power spectral density using a sliding window opens the possibility to detect the onset of transient processes. Synthetic signals and two test power systems with different dynamic characteristics are used to evaluate the potential application in large systems. [ABSTRACT FROM AUTHOR]

This paper presents a control scheme of a wide-area controlled static VAr compensator (WAC-SVC) and its real-time implementation in a hardware-in-the-loop (HIL) simulation scheme with three control objectives: (1) to increase the critical clearing time, (2) to damp the power oscillations, and (3) to minimize the maximum line current. The proposed control scheme considers a correction strategy to compensate the delays up to 200 ms. In addition to this, a generator tripping scheme based on synchrophasor measurements to determine the proximity to the loss of synchronism is proposed. A delay compensation algorithm based on polynomial approximations is also developed. The proposed WAC-SVC is experimentally validated using a Real-Time Digital Simulator platform (RTDS), industrial communication protocols, a commercial device for PMU-based control implementations, and digital relays with PMU capability. The real-time simulation results confirm its effectiveness and feasibility in real industrial applications. Furthermore, practical guidelines to implement this kind of control schemes are provided. [ABSTRACT FROM AUTHOR]