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Using propagation characteristics of travelling wave, an extra high speed busbar protection technique is proposed. If a fault occurs on the transmission line, the forward and backward travelling waves will be generated. When a fault occurs on the busbar, the detected initial travelling waves on all lines connected to this busbar will come from their backs, which are positive direction travelling waves...
With the increased focus on Electric Vehicles (EV) research and the potential benefits they bring for smart grid applications, there is a growing need for an evaluation platform connected to the electricity grid. This paper addresses the design of an EV test bed, which using real EV components and communication interfaces, is able to respond in real-time to smart grid control signals. The EV test...
The requirements of distribution grids are increasing. In a smart grid, critical states and overstress are predictable. If any kind of load shedding is available then grid expansions can be alleviated. Demand response could be used to motivate consumers to load shifting via incentives. Potential of load shifting in households exists, but remains uncertain so far due to the lack of knowledge about...
The number of doubly fed induction generators (DFIG) connected to the existing network has increased significantly worldwide during the last two decades. This triggers off manufactures to improve the performance of DFIG through robust and reliable design. The stator in DFIG is directly connected to the grid whereas the rotor is interfaced to the grid through two voltage source converters; rotor side...
This paper presents an effective method for placement of DG units in multiphase distribution networks based on system voltage profile. The approach consists of utilizing the positive sequence voltage ratio Vcollapse/Vno-load to identify the weakest three-phase bus for the installation of DG units. DG ratings are determined by evaluating their impacts on voltage profile, grid losses and maximum loading...
This paper describes a nonlinear controller for a type of voltage-source converter based high voltage direct current called Back-to-back static synchronous compensator (BTB STAT-COM) system with asymmetrically structured converters. The BTB STATCOM employs a pulse width modulation technology for a rectifier station and a multipulse technology for an inverter station. To improve robustness and simplify...
We have recently observed and justified that the optimal power flow (OPF) problem with a quadratic cost function may be solved in polynomial time for a large class of power networks, including IEEE benchmark systems. In this work, our previous result is extended to OPF with arbitrary convex cost functions and then a more rigorous theoretical foundation is provided accordingly. First, a necessary and...
The increasing relevancy of renewable energy sources in the production of electricity and therewith the increasing decentralized in-feed of energy modifies the request on electrical grids more and more. Especially photovoltaic had a rapid increase in the last years. In Germany with only a few exceptions photovoltaic is installed in the low and medium voltage level grid. For instance along with this...
A review of the issues for supporting learning of power engineering in Australia is presented in this paper. The learning needs of students and the support available in blended learning and through distance educations are explored in this review. Specific software tools to assist the learning environment are appraised and the relevance for the next generation of power engineers assessed.
The objective of this paper is to show a methodology to estimate transmission line parameters. The method is applied in a single-phase transmission line using the method of least squares. In this method the longitudinal and transversal parameters of the line are obtained as a function of a set of measurements of currents and voltages (as well as their derivatives with respect to time) at the terminals...
Each vessel has a different load profile based on its application. Among the vessels, the ones that have electrical propulsion systems with high fluctuations of propulsion demand power incur poor fuel consumption efficiencies due to: a) low loading of the generators and the lower efficiency in lower loads, and b) variations in the output power of the generators. Therefore, it may be economically feasible...
Load in distribution networks is normally measured at the 11kV supply points; little or no information is known about the type of customers and their contributions to the load. This paper proposes statistical methods to decompose an unknown distribution feeder load to its customer load sector/sub-sector profiles. The approach used in this paper should assist electricity suppliers in economic load...
This paper presents a new method based on the cost benefit analysis for optimal sizing of an energy storage system in a microgrid (MG). The unit commitment problem with spinning reserve for MG is considered in this method. Time series and feed-forward neural network techniques are used for forecasting the wind speed and solar radiations respectively and the forecasting errors are also considered in...
Electric utilities are steadily increasing the quantity of intelligent field devices deployed on distribution feeders to improve service reliability and optimize grid efficiency and capacity. As the individual capabilities of the field devices expands, there is a corresponding increase in data flow and two-way communications exchange between field devices and the central control system. While there...
Transmission line fault location methods typically need measurements from at least one end of the faulted line. Sparse measurement based fault location method using phasor measurements from different substations located near the faulted line can be applied if the measurements are not available from any of the line ends. This method uses data and model described in both bus-branch and node-breaker...
A large microgrid project is nearing completion at Alameda County's twenty-two-year-old 45 ha 4,000-inmate Santa Rita Jail, about 70 km east of San Francisco. Often described as a green prison, it has a considerable installed base of distributed energy resources (DER) including an eight-year old 1.2 MW PV array, a five-year old 1 MW fuel cell with heat recovery, and considerable efficiency investments...
Estimating the arbitrage value of storage is an important problem in power systems planning. Various studies have reported different values based numerical solutions of variations of a basic model. In this paper, we instead rely on a closed form solution for storage control. The closed form highlights the right type of forecasting that is required and allows large horizon problems to be solved. We...
In recent years, population-based methods (evolutionary algorithms, particle swarm methods, etc.) have emerged as an effective tool for component and system design. Although relatively straightforward to apply, to capitalize on their potential, one must be able to explore a large design space. Herein a magnetic equivalent circuit model is described to enable large-design-space exploration of salient-pole...
This paper describes a proof of concept for forecasting the long-term amounts of energy efficiency. All six New England states and other stakeholders have urged the ISO to develop a methodology to account for the growth of state-sponsored energy efficiency (EE) programs beyond the three year Forward Capacity Market (FCM) time horizon. In response, ISO New England has gathered supporting information...
This paper discusses three aspects of demand response through a case study of a US utility: 1) how load profile changes due to demand response; 2) how much energy has been saved annually; 3) whether the load forecasts have been affected by demand response. A regression based approach is deployed to try to answer these questions. The results show that for this particular utility, the demand response...
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