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This paper deals with the selection of feedback signal(s) that retain the modal behavior of power system electromechanical dynamics under varying operating circumstances. The approach seeks signals that have relatively large magnitude of residue, less variation of the magnitude and phase angle, sufficient gap between the critical pole-zeros, and least sensitive to other modes. The methodology is tested...
The paper investigates the effect of age related failure of power transformers on the identification of most critical transformer sites for system reliability. The end-of-life failure model of power transformers is modified first to integrate loading conditions effect. The adopted Arrhenius-Weibull probability distribution, which represents the effect of thermal stress on the transformer's end-of-life...
First, we investigate the technical and economic potential of autonomously operating voltage control strategies in low voltage grids with high photovoltaic penetration. The investigated control strategies are based on the reactive power control capabilities of modern photovoltaic inverters and the application of distribution transformers with onload tap changers. We present a methodology for assessing...
This paper shows that a previously proposed linear-system identification method based on frequency partitioning and adaptive weighting can be successfully applied to the phase-domain frequency-dependent modeling of overhead transmission lines for electromagnetic transient (EMT) simulations. As the framework of the phase-domain modeling, the universal line model (ULM) is used, and the frequency responses...
A suitable networked control scheme and its stability analysis framework have been developed for controlling inherent electromechanical oscillatory dynamics observed in power systems. It is assumed that the feedback signals are obtained at locations away from the controller/actuator and transmitted over a communication network with the help of phasor measurement units (PMUs). Within the generic framework...
The integration of intermittent generation in power grids, such as wind energy, imposes new challenges for transmission congestion management. In order to solve this problem, energy storage systems (ESS) have been proposed in the literature, as they provide an efficient mechanism for balancing variability while reducing operational costs. This paper presents a comprehensive analysis of the dynamic...
Wind turbines are required to meet grid interconnection codes for voltage ride-through, which mandate that they should not disconnect during a specified range of grid disturbances. One of the tasks of a turbine's design verification process is to ensure that it will be able to withstand any such event. This paper sets forth a powerful computational technique for design verification of Type-4 permanent-magnet...
Phasor measurement units (PMUs) provide the basis for synchrophasor measurements, which are good data sources for capturing power system dynamic behavior. The recently published IEEE Standard C37.118.1-2011 characterizes the dynamic performance of synchrophasor measurements with two performance class filters: P-class and M-class. Practical implementation of a PMU to meet all dynamic requirements is...
Under the global trend of renewable energy development, various advanced techniques such as forecasting algorithm, intelligent computation, and optimal control are expected to make the complex and uncertain renewable energy system stable and profitable in the near future. This paper presents a new control strategy for large-scale wind energy conversion systems (WECSs) to achieve a balance between...
Single-pole tripping (SPT) operation imposes problem to many power network relaying schemes. In this paper the directional relaying issue for faults during SPT condition is addressed. Algorithms applying negative sequence components of fault voltage and current for directional relaying find limitation during SPT as the prefault signals also contain negative sequence components. This paper proposes...
This paper presents an investigation of hydro power plants with pelton-type turbine-generator sets that are coupled hydraulically and electrically. In particular, the dynamic behavior and speed performance of this type of power plants at black-start is analyzed using singular value decomposition (SVD) and relative gain array (RGA). Following, robust control theory is used to design a hydro-stabilizer...
This paper proposes a chronological probability model of photovoltaic (PV) generation on the basis of conditional probability and nonparametric kernel density estimation. In addition to randomness of PV power, the correlation of PV powers between adjacent time points and the uncertainty of start and end moments of PV output can be represented. The proposed model can be employed to produce random PV...
Compared with traditional current transformers (CTs), electronic current transformers (ECTs) are characterized by small volume, light weight, good isolation, good linearity, and easy digitization. Hence, ECTs are one of the primary devices for signal digitization for supervising intelligent substations. We design a coreless ECT using Hall sensors as well as its mechanism and circuit configuration...
This paper develops a self-coherence method for detecting sustained oscillations using phasor measurement unit (PMU) data. Sustained oscillations decrease system performance and introduce potential reliability issues. Timely detection of the oscillations at an early stage provides the opportunity for taking remedial reaction. Using high-speed time-synchronized PMU data, this paper details a self-coherence...
For distribution networks with a high penetration of photovoltaic (PV) systems, overvoltage is a common and major issue that needs be addressed to not only assure reliable and secure system operation, but also to fully utilize PV generation capacity. A new real power capping method is proposed in this paper to prevent overvoltages by adaptively setting the power caps for PV inverters in real time...
This paper presents a hierarchical decentralized agent-based network reconfiguration methodology to minimize power losses for smart distribution systems. A novel formulation of the network reconfiguration problem is given in which the switch states are the decision variables, and a single-loop branch-exchange heuristic algorithm is used to solve the optimization problem. The entire distribution system...
In this paper a mixed integer quadratic programming (MIQP) is proposed to solve the dynamic economic dispatch (DED) with valve-point effect (VPE) where the non-linear and non-smooth cost caused by VPE is piecewise linearized. However if the DED with VPE is directly solved by the MIQP in a single step, the optimization suffers convergence stagnancy and will run out of memory. In this paper the multi-step...
This paper presents the load flow modeling and steady-state capabilities of the bundle-controlled Line Impedance Modulator (LIM). This distributed FACTS device is under development for the management of power flows. In particular, the paper presents the back-to-back interconnection of two Bundle-Controlled Line (BCL) segments. The LIM configuration is very interesting from an economic and operational...
The short circuit contribution of a Type 3 wind farm connected to a series compensated line is affected by subsynchronous interactions making it essential to model such behavior. Fundamental frequency models are unable to represent the majority of critical wind generator fault characteristics. The complete electromagnetic transient (EMT) models, though accurate, demand high levels of computation and...
Aluminum production relies on the smelting process which consumes huge electrical energy. One possible solution to reduce the fossil fuel consumption by aluminum production is the integration of wind power. Based on this background, this paper studies an isolated power system for aluminum smelting production with a high penetration of wind power. A dynamic model of the aluminum smelter load (ASL)...
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