Search

Special Feature that lists the names of people involved in the review of technical papers for the IEEE Transactions on Industry Applications and Industry Applications Magazine. [ABSTRACT FROM AUTHOR]

This paper presents an algorithm for detection, classification, and characterization of voltage sags and swells in electricity networks using three-phase voltage ellipse parameters. The proposed method employs the instantaneous magnitude of three-phase voltage signals in three axes, which are separated from each other by 120 ^\circ . Thus, the resultant rotating vector, namely, the three-phase voltage vector, traces an ellipse. Then, the parameters of the ellipse, which include minor axis, major axis, and inclination angle, are used to develop the proposed algorithm for classification and characterization of voltage sags and swells. The proposed method is validated using real data of the IEEE working group and some measured real data of the Belgian transmission grid. The method is further tested for the sags and swells generated due to balanced and unbalanced faults at different buses, in test distribution networks (radial and mesh type) embedded with distributed generation and in a practical distribution network of Australia. This paper also demonstrates the proposed algorithm as a real-time sag/swell monitoring tool. [ABSTRACT FROM PUBLISHER]

Stand-alone operation of distributed generations (DGs) under an islanded mode is achieved by appropriate switching of controllers from grid-parallel to stand-alone mode. Conversely, during grid restoration, reverse switching operation is employed. These operations cause voltage quality issues; among these issues, voltage dips and swells are two crucial events that are encountered during and subsequent to islanding. This paper characterizes the voltage dips and/or swells caused by the islanding of DG and its subsequent pre- and post-islanding events. Pre-islanding events encompass the fault-initiated islanding scenarios, whereas postislanding events are associated with transitional state, island stabilization, and grid-reconnection states. Considering pre- and post-islanding scenarios, this paper classifies and characterizes the voltage dips and swells using an algorithm incorporating three-phase voltage ellipse and three-dimensional (3-D) polarization ellipse parameters. Three-phase voltage ellipse parameters, namely, major axis, minor axis, and inclination angle of an ellipse, are exploited for characterization and classification of voltage dips/swells based on their affected phases, whereas 3-D polarization ellipse parameters are employed for classifying seven dip types, namely, A, B, D, F, E, C, and G. Islanding and its subsequent scenarios are simulated using a test distribution network of Australia embedded with DG, and the voltage dips and swells are characterized using the proposed algorithm. [ABSTRACT FROM AUTHOR]

In practice, the load-curve and distributed generation (DG) penetration level determines the power imbalance level that a network can experience if islanding occurs. Therefore, with the prior knowledge of load-curve and DG penetration level, the setpoint of rate-of-change-of-frequency (ROCOF) relays can be adjusted so as to make them suitable for a real network. This paper first investigates the subcritical power imbalance region of ROCOF relays through analytical formulation followed by extensive simulation study in order to establish the maximum boundary limit of ROCOF's nondetection zone (NDZ) under all possible deficit/excess of active and/or reactive power imbalance scenarios. Second, ROCOF's reliability (assessed by detection rate and false alarm rate) is expressed analytically and then, validated numerically by simulating a test network of Australia in MATLAB and OPAL-RT real-time digital simulation platform. Finally, ROCOF's performance is assessed through receiver operating characteristics curves and a detailed reliability study under variable setpoints and detection time of the relays; the assessment considers the number of islanding events associated with the time-wise percentage of power imbalance level computed from the net load demand and variable DG penetration in a real network. All these test results demonstrate a clear operational guideline for ROCOF relay. [ABSTRACT FROM AUTHOR]

Plug-in electric vehicles (PEVs) have a potential amount of battery energy storage capacity, which is not fully utilized in regular day-to-day travels. The utilization of spare PEV battery capacity for grid support applications using vehicle-to-grid concept is becoming popular. Depending on the stress on the grid during peak load periods, a small amount of peak-shaving support from the PEVs in a feeder can be useful in terms of grid support. However, as the PEV batteries have limited capacity and the capacity usage is also constrained by travel requirements, a strategy is proposed in this paper for an effective utilization of the available PEV battery capacity for peak shaving. A controllable discharging pattern is developed to most utilize the limited PEV battery capacity when peak shaving is most valuable based on the demand pattern. To ensure an effective use of the available PEV battery capacity for travel, which is the main usage of the PEVs, and for grid support application, dynamic adjustments in PEV discharging rates are made. The effectiveness of the proposed strategy is tested using a real distribution system in Australia and based on practical PEV data. [ABSTRACT FROM AUTHOR]

Unscheduled charging of a high number of plug-in electric vehicles (PEVs) can raise the peak electric load and affect the power quality (PQ) of the distribution power grids. This necessitates devising novel solutions to support the power grids when PEVs are being charged by controlling the PEVs’ charging load. In this paper, an intermediate control unit for the commercial battery chargers is developed in-house, which can directly control the PEV charging load by modifying the power levels during ac charging. Furthermore, field measurements are conducted to investigate the impacts of mass-produced PEVs on the point of common coupling during charging by the developed unit with different power levels. In addition, a home charging management system that employs the developed unit is designed. The results from the field experiments, together with the model-based case studies, demonstrate that the developed unit can be readily adopted for direct control of the charging loads of mass-produced PEVs, without the modification of the existing recharging equipment. Moreover, in the context of charging management, the electricity cost can be minimized, whilst the preferences of the PEV owners can be realized and the PQ of the distribution networks can be maintained simultaneously. [ABSTRACT FROM AUTHOR]

Retaining rings are an important, and the most highly stressed, component of the entire turbogenerator system. Arcing in retaining rings is a very serious problem as it can easily escalate to a full-blown failure. In this paper, we investigate this arcing problem in the retaining rings. We determine the most likely mechanism by which arcing occurs and the type of events that lead to it. Specifically, we try to test two different mechanisms that could have led to the indications of arc. The first one is sparking due to high field effects (or high voltage gradient across the contact junction) and the other is a make-and-break contact arcing owing to the presence of inductance in the system. Experiments performed to measure the contact resistance between the retaining ring and mild iron piece indicate that even very high fault currents cannot produce enough voltage drop to cause sparking. Transient three-dimensional finite-element simulations show that a break in a relatively small contact region, which can be part of a bigger contact area, can generate localized voltage spikes that are high enough to lead to arcing. Interestingly, this can happen at relatively low currents. Furthermore, hardware experiments in the laboratory confirm the possibility of generation of arcs due to a make-and-break contact at low currents. [ABSTRACT FROM PUBLISHER]

This article determines the optimal capacity of solar photovoltaic (PV) and battery energy storage (BES) for grid-connected households to minimize the net present cost of electricity. The real-time rule-based home energy management systems using actual annual data of solar insolation, ambient temperature, household electricity consumption, and electricity rates are used in the optimization process. The above-mentioned technique is applied to two system configurations—household with a solar PV and a BES. The uncertainty analysis is implemented using ten years of real data to confirm the optimal results. An accurate cash flow analysis is also presented to illustrate the customer payment in each year during the project lifetime. The sensitivity analysis is conducted by varying the cost and capacity of system components, grid constraint, average daily electricity demand, and retail price of electricity. A typical grid-connected household in South Australia is considered as the case study. A practical guideline is presented for the residential consumers in South Australia to select the optimal PV/BES based on their daily average electricity demand and the available rooftop space for PV installation. Finally, the proposed optimization method is applied to households of other Australian States and a comparison of results is presented. [ABSTRACT FROM AUTHOR]

With recent developments in understanding the adverse health effects of diesel particulate matter (DPM) and growing emphasis on sustainability, zero-emission electric vehicles are becoming an increasingly common option in underground mining systems. As exposure regulations become stricter and with potential savings in the cost of ventilation, fuel, and consumables, there is also rising economic incentive to consider alternatives to diesel machinery. As a result, the diesel–electric debate is fundamental to any underground mining company's triple bottom line. A cost–benefit analysis for electric load haul dump units (eLHDs) was conducted in the context of Western Australian underground hard rock mines. This included a review of the issues affecting the diesel–electric debate and the development of a parametric life-cycle-cost model. The results indicate that eLHDs are not yet a universal solution to all underground mining systems. eLHDs can offer lower operating costs and do contribute many qualitative benefits, particularly with respect to reduced exposure to DPM. However, they also have several drawbacks, primarily associated with trailing cable management. Nevertheless, with a suitable mine design, eLHDs are a viable option and could provide a pathway for zero-emission electric machinery in the Australian mining industry. Preamble —Western Australia is one of the world's leading mineral provinces. In the 2012–2013 financial year, Western Australia's mineral and petroleum sales totaled A$102 billion, representing some 42 $\%$ of Australia's total merchandise exports. As such, changes to the Western Australian mining industry has national and international economic implications. [ABSTRACT FROM PUBLISHER]