A survey on modeling of microgrids - from fundamental physics to phasors and voltage sources

Microgrids have been identified as key components of modern electrical systems to facilitate the integration of renewable distributed generation units. Their analysis and controller design requires the development of advanced (typically model-based) techniques naturally posing an interesting challenge to the control community. Although there are widely accepted reduced order models to describe the dynamic behavior of microgrids, they are typically presented without details about the reduction procedure---hampering the understanding of the physical phenomena behind them. Preceded by an introduction to basic notions and definitions in power systems, the present survey reviews key characteristics and main components of a microgrid. We introduce the reader to the basic functionality of DC/AC inverters, as well as to standard operating modes and control schemes of inverter-interfaced power sources in microgrid applications. Based on this exposition and starting from fundamental physics, we present detailed dynamical models of the main microgrid components. Furthermore, we clearly state the underlying assumptions which lead to the standard reduced model with inverters represented by controllable voltage sources, as well as static network and load representations, hence, providing a complete modular model derivation of a three-phase inverter-based microgrid

Optimal Fault Location in Distribution Systems Using Distributed Disturbance Recordings

In case of a power system disturbance, main focus of the utility is to keep the duration of the interruption as short as possible. This requires fast identification of the fault location, isolation of the defected components and power supply restoration. To achieve the goal “fast and accurate fault location”, distributed fault recordings can be used. Measurements can be retrieved from substation, reclosers or distributed generator relays. This paper presents a new fault location scheme in distribution systems using distributed voltage and current recordings. The algorithm transfers voltage and current from measurement devices through the faulted line. Fault distance is then calculated using a single- or two-ended fault location method. Statistical errors on phasors and networks parameters are considered to obtain an optimal estimation of the fault location. Standard deviation of the fault distance estimate is also calculated. The performance of the algorithm is verified on a simulated distribution system.info:eu-repo/semantics/publishe

Real-time identification of interarea oscillating modes in power systems

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In touch with the past? Bodies, monuments and the sacred in the Manx Neolithic

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Response-based System Integrity Protection Scheme Against Voltage Instability Using Phasor Measurement Units

The aim of this paper is to present a new method to counteract voltage instabilities in power systems using Phasor Measurement Units (PMU). This System Integrity Protection Scheme (SIPS) allows detecting on-line a critical situation and taking countermeasures at the weakest location. The method could be first implemented as a monitoring with a meaningful visualization. The advantages of the algorithm proposed in this paper are its simplicity and its robustness. The paper shows results of monitoring and protection based on dynamic simulations.info:eu-repo/semantics/publishe

Considerations about synchrophasors measurement in dynamic system conditions

This paper focuses on some concepts that are to be considered to ensure interoperability of phasor measurement units (PMU) during dynamic phenomena. Interoperability of devices in dynamic system conditions is needed to allow accurate analysis and, in the near future, control of phenomena like power system oscillations. The paper emphasizes the need to extend the IEEE standard to ensure the measurement latency and accuracy are known during field measurements. It also introduces a sequential logic aiming at providing the user with more robust measurements, together with more information about the measurement quality. © 2009 Elsevier Ltd. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Meter placement impact on distribution system state estimation

This paper discusses the criteria that must be considered for the placement of new measurements in distribution networks in order to obtain the best state estimation performances. A better network state monitoring will improve all the other network management tasks. The impacts of the measurement device placement on the state estimation accuracy and on the bad data detection capabilities are illustrated. To ease the comparison of different measurement sets, a visualization method of the expected performances of the state estimator is presented. The paper finally gives measurement placement recommendations based from a literature review and our experience gained from simulations.info:eu-repo/semantics/publishe

A Synchrophasor Measurement Algorithm Suitable for Dynamic Applications

This paper describes a scheme to improve the overall performance of Phasor Measurement Units (PMU), such that the estimated phasors can be used for a wide range of applications in real-time. The main concern is the accuracy and robustness of the phasor estimation outside steady state, which is strongly influenced by the accuracy of the frequency estimation. The need to complement the phasordata with information about the phasor quality is also emphasized.info:eu-repo/semantics/publishe

Comparison of Thevenin's Equivalent based Methods to Monitor Voltage Stability

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