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The emerging interest in deployment of plug-in electric vehicles (PEVs) in distribution networks represents a great challenge to both system planners and owners of PEV-parking lots. The owners of PEV-parking lots might be interested in maximizing their profit via installing charging units to supply the PEV demand. However, with stringent rules of network upgrades, installing these charging units would be very challenging. Network constraints could be relaxed via controlling the net demand through integrating distributed generation (DG) and/or storage units. This paper presents an optimization model for determining the optimal mix of solar-based DG and storage units, as well as the optimal charging prices for PEVs. The main objective is to maximize the benefit of the PEV-parking lot's owner without violating system constraints. Two cases are considered in this paper: uncoordinated and coordinated PEV demand. A novel mathematical model is further developed whereby the behavior of vehicles’ drivers, in response to different charging prices, is considered in generating the energy consumption of PEVs. [ABSTRACT FROM PUBLISHER]

This article presents a new approach to enhance the capabilities of flywheel energy storage systems to enable increasing the integration of small-scale photovoltaic distributed generation units in distribution systems. The storage capabilities of the flywheel energy storage systems are utilized to suppress the system voltage disturbances caused by the intermittent output power of the photovoltaic distributed generation sources in distribution systems. A dynamic model of the flywheel energy storage systems is presented. The flywheel energy storage systems model is simulated in a practical residential distribution network with small-scale photovoltaic distributed generation sources using PSCAD/EMTDC. The performance of the system is studied before and after installing the flywheel energy storage systems. The simulation results show that utilizing the flywheel energy storage systems technology in distribution systems with installed photovoltaic distributed generation sources can effectively reduce the frequent operation of the system automatic voltage regulators and increase the overall utilized energy of the installed photovoltaic distributed generation sources. [ABSTRACT FROM AUTHOR]

The recent deployment of distributed generation has led to a revolution in the use of distribution systems and the emergence of smart-grid concepts. Smart grids are intended primarily as a means of facilitating the integration of renewable energy sources and of achieving greater system reliability and efficiency. Energy storage systems offer a number of benefits that can help utilities move toward those goals. One of those benefits is the capacity to improve system reliability through successful islanding operation. This paper proposes a methodology for the cost-effective improvement of system reliability through the allocation of distributed storage units in distribution systems. The costs of energy storage installation are optimized with respect to reliability value expressed as customers' willingness to pay in order to avoid power interruptions. The primary goal of this research was thus to determine the optimal combination of storage units to be installed and the loads to be shed so that all possible contingencies can be effectively addressed. A probabilistic approach is therefore adopted that includes consideration of the stochastic nature of system components. [ABSTRACT FROM PUBLISHER]

Recent deployment of distributed generation has led to a revolution in distribution systems and the emergence of “smart grid” concepts. The smart grid mainly intends to facilitate integration of renewable energy sources and to achieve higher system reliability and efficiency. Different distributed generation types found in modern distribution systems can be classified into two main categories: intermittent- and dispatchable-based distributed generation; the latter has a unique capability of enabling successful islanding operation, thus improving system reliability. This article proposes a methodology for allocating dispatchable distributed generation units in distribution systems to economically improve system reliability. Distributed generation installation and operation costs are to be optimized against the reliability value, expressed as customers’ “willingness to pay” (WTP) to avoid power interruptions. Therefore, the main goal of this research work is to determine the optimal combination between distributed generation units to be installed and loads to be shed during all possible contingencies. A probabilistic load model is adopted to determine the optimal size of allocated distributed generation units. [ABSTRACT FROM AUTHOR]

In this paper a novel coordinated voltage control scheme is proposed to enable voltage regulator to efficiently regulate the voltage of multiple feeders in the presence of DGs. The proposed technique is based on placing a remote terminal unit (RTUs) at each DG and each line capacitor. These RTUs coordinate together, through communication, and form a multiagent system. Detailed analysis is given for the estimation of the voltage profile based on the RTUs readings. The conditions under which the usage of one voltage regulator for the regulation of multiple-feeders fails are presented along with proposed solutions for such situation. Simulation results show that this technique enable a considerable increase in the allowed DG injected power to the system. [ABSTRACT FROM PUBLISHER]

The non-detection zone is a concept used to evaluate anti-islanding detection methods. The non-detection zone is defined as the loading condition for which an islanding detection method would fail to operate in a timely manner, and it is represented in terms of the load parameters. This article proposes a new three-dimensional non-detection zone representation for quantifying the effectiveness of frequency drift islanding detection methods. The proposed non-detection zone model is represented in terms of active and reactive power mismatch and load quality factor. Various two-dimensional non-detection zone models proposed in the literature are analyzed to highlight the limitations of each model. The analysis is conducted on three different islanding detection methods, including over-frequency protection/under frequency protection, active frequency drift, and Sandia frequency shift methods. The analytical model of the two dimensional non-detection zone representations is presented, and each model is validated through simulation results. The results show that representing the non-detection zone in a two-dimensional space is not sufficient to accurately determine all non-detectable loading conditions. The proposed three-dimensional non-detection zone representation is capable of modeling all possible loading conditions and provides a better approach for assessing islanding detection methods with resistance-inductance-capacitance loads. [ABSTRACT FROM AUTHOR]

Distributed Generation (DG) is used widely in the modern distribution systems. This paper proposes a novel functionality of the interface between DG and the utility network to mitigate the voltage flicker and to regulate the voltage at the Point of Common Coupling (PCC) in addition to its main function of controlling the power flow. A new control algorithm for the DG interface based on the Hilbert transform (HT) is presented. The HT is employed as an effective technique for tracking the voltage flicker levels in distribution systems. The mathematical simplicity of the proposed technique, compared with the commonly used algorithms in the literature, renders them competitive candidates for the on-line tracking of voltage flicker. The accurate tracking of the HT facilitates its implementation for the control of flicker mitigation devices. Simulation results are provided to verify the tracking capabilities of the HT and to evaluate the performance of the proposed DG interface for multifunction operation. [ABSTRACT FROM PUBLISHER]

Distributed Generation (DG) exists in distribution systems and is installed by either the utility or the customers. This paper proposes a novel utilization of the existing DG nonlinear interface not only to control the active power flow, but also to mitigate unbalance and harmonics, and to manage the reactive power of the system. The proposed Flexible Distributed Generation (FDG) is similar in functionality to FACTS, but works at the distribution level. Moreover, a novel ADAptive LINEar neuron (ADALINE) structure is presented. The new structure is applied to multi output (MO) systems for parameter tracking/estimation, and is called MO-ADALINE. It is dedicated to symmetrical components estimation. The control loop combines a Fuzzy Logic Controller (FLC) for voltage regulation, and a processing unit-based ADALINE to deal with unbalance, harmonics and reactive power compensation. One advantage of the proposed control system is its insensitivity to parameter variation, a necessity for distribution system applications. Simulations of the suggested FDG based control algorithm are conducted to evaluate the performance of the novel system. [ABSTRACT FROM AUTHOR]