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This paper introduces a concept of real-time optimization of hybrid fuel-cell power plants as an alternative distributed generation source that improves the power quality and reliability of the power grid. One of the most important issues of plant operation is the optimal control of the power plant, leading to significant economic and environmental benefits. As a commercialized fuel cell technology,...
This paper presents a smart metering network for monitoring energy consumption and power quality of building integrated electric vehicle charging network. The smart metering network consists of smart metering devices, a ZigBee communication network, and a central system for power calculation and power quality analysis. The smart metering device captures current and/or voltage waveform and performs...
This paper presents a useful and practical approach for assessing the impact of electric vehicles on the electric power distribution system while keeping to a manageable volume of detailed circuit and equipment studies. This paper addresses electric vehicles as an electric load only and does not consider the potential of the vehicle being a generation source. It also only addresses the substation,...
Summary form only given. Alabama Power Company has an ongoing program to improve the voltage profile of the 115 kV transmission system. This program includes the installation of a large number of distribution line capacitors. Initially, the distribution line capacitors were installed in the traditional fashion as fixed installations. However, with the wide spread deployment of Distribution Automation,...
This paper presents the analysis of unique features and classification method for identifying the root cause of overhead distribution fault events. In particular, the paper focuses on faults caused by animal contacts, tree contacts and lightning-induced disturbances. The proposed methodology is implemented and tested using 148 real-world fault events. The methodology has a classification rate of 90%,...
This paper aims to give an overview on main PQ development in Europe. It focuses basically on recent legislative, regulatory, standardization, voltage quality monitoring and education initiatives summarizing the latest outcomes.
Synchronized measurements became recently an affordable tool ready to be implemented not only at transmission system level but also at distribution level, mostly in conjunction with the applicability of the smart grid approach. As a preliminary step of introducing PMUs on a larger scale, extensive measurements campaigns, primarily dedicated to power quality purposes, were conducted within medium and...
This paper focuses on analyzing the impact of electromechanical oscillations caused by distributed synchronous generators on power distribution systems from the power quality point of view. The electromechanical oscillations are natural responses of synchronous generators to a mismatch in their net torques, and thus, are present in every distribution system equipped with such generators. In this work,...
Harmonics is a growing concern to both electric utilities and their customers. Nonlinear loads in large-scale industries are important causes for the harmonic currents and voltage distortion. In modern steel manufacturing facilities, Arc furnaces and rolling mill loads are the two major nonlinear loads. They generate significant harmonic currents that flow through the plant and utility power system...
This paper identifies and quantifies the unique characteristics of current-limiting fuse operation as seen in the current and voltage waveforms recorded at a monitoring station located upstream from the fault. Characteristics that can be used to identify current-limiting fuse operations by visual inspection are described. More characteristics are extracted using signal processing methods. These characteristics...
In this paper, variable weight theory and set pair analysis (SPA) theory are applied to comprehensive evaluation of power quality. Among existing comprehensive evaluation methods of power quality, the problems about index uncertainty and imbalance case are less considered. The application of variable weight SPA, for ensuring identical discrepancy contrary (IDC) of unsure system, effectively reduces...
A comprehensive voltage imbalance sensitivity analysis and stochastic evaluation based on the rating and location of single-phase grid-connected rooftop photovoltaic cells (PVs) in a residential low voltage distribution network are presented. The voltage imbalance at different locations along a feeder is investigated. In addition, the sensitivity analysis is performed for voltage imbalance in one...
Ferroresonance is one of the most destructive and longest known power quality disturbances in the history of ac power systems. The undamped ferroresonant oscillations that occur between system capacitances and magnetizing inductances of transformer cores can cause severe damage and disruption to power networks. In this paper, ferroresonance in transformers is investigated with the aid of a nonlinear...
This paper presents the power quality analysis of a Synchronous Static Series Compensator (SSSC) connected to a high-voltage transmission network. The analysis employs a simplified harmonic equivalent model of the network that is described in the paper. To facilitate the calculations, a software toolset was developed to measure the voltage harmonics content introduced by the SSSC at the Point of Common...
The paper presents a real-time optimization approach based on the Newton-type algorithm (NTA) and the least squares (LS) method for power system frequency estimation. A non-linear non-recursive Newton algorithm is utilized to track the modulation effect of frequency variation on the on-line estimation of the phase angle. The LS curve fitting technique extracts the instantaneous power system frequency...
Modern household customers use many power electronic based devices for their daily usage. Those devices emit harmonic current pollutions and eventually increase harmonic voltage distortion level in the network. In the future network, the background harmonic pollution in the MV and upstream networks could increase with the integration of more distributed generations. Thus, the harmonic related problem...
In recent years, various types of gas-fueled combined heat and power (CHP) systems have been developed and introduced into sites such as hospitals, hotels, commercial buildings, district heating & cooling centers, factories, etc., to increase energy savings and reduce greenhouse gases. Typical components integrated into CHP systems are gas engines (GE), gas turbines (GT), and fuel cells (FC);...
Among various types of battery energy storage systems (BESSs), NAS battery is the most promising products. NAS battery is a commercial product implemented widely in the world. The first purpose of BESS was improvement of load factors. The second purpose is improvement of power quality, especially against voltage-sag. The recent interest is oriented to utilize BESS to mitigate the intermittency of...
This paper proposes a scheme based on the embedding theorem to locate and classify the transient disturbances in power system signals. The disturbance signals are transformed to the phase space, where the normal part of the signal and the disturbance form two waveforms that can be distinguished from each other, and the location and classification are based on the information obtained from the embedded...
This paper presents a voltage-power droop/frequency-reactive power boost (VPD/FQB) control scheme that allows multiple voltage source converters (VSCs) to operate in parallel in a VSC fed microgrid. Each current controlled VSC in such a microgrid has its own VPD/FQB controller that sets its current references to regulate the voltage and frequency of a common microgrid bus. By drooping the voltage...
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