Topic
Power-flow study
About: Power-flow study is a research topic. Over the lifetime, 8091 publications have been published within this topic receiving 155053 citations. The topic is also known as: load-flow study.
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15 May 1979
TL;DR: The paper attempts to provide some clarification of the main fundamental analytical and computational, issues involved in the design of an LP-based method for the rescheduling of power-system operation.
Abstract: Linear and related programming methods have application in transmission planning, security dispatch and emergency control of power systems. With a large still-growing body of literature on the subject, this paper offers a short review of the available LP approaches, techniques and formulations, with due emphasis on state-of-the-art versions. The differences between primal and dual methods and sparse and nonsparse formulations are exposed, and various important techniques such as relaxation, upper bounding and separable programming are dealt with. Thus the paper attempts to provide some clarification of the main fundamental analytical and computational, issues involved in the design of an LP-based method for the rescheduling of power-system operation.
107 citations
TL;DR: Various ways, in which electrical distance might be defined for empiric power systems are proposed, and how well each candidate distance measure may be embedded in two dimensions are proposed.
Abstract: Recent work, using electrical distance metrics and concepts from graph theory, has revealed important results about the electrical connectivity of empiric power systems. Such structural features are not widely understood or portrayed. Power systems are often depicted using unenlightening single-line diagrams, and the results of loadflow calculations are often presented without insightful elucidation, lacking the necessary context for usable intuitions to be formed. For system operators, educators, and researchers alike, a more intuitive and accessible understanding of a power system's inner electrical structure is called for. Data visualization techniques offer several paths toward realizing such an ideal. This paper proposes various ways, in which electrical distance might be defined for empiric power systems, and records how well each candidate distance measure may be embedded in two dimensions. The resulting 2-D projections form the basis for new visualizations of empiric power systems and offer novel and useful insights into their electrical connectivity and structure.
107 citations
TL;DR: Simulation results are shown to show the advantages of fast converging properties of GOA over GA and PSO techniques and the effect of EV load growth and the effects of uncertainties in DGs and distribution system load are shown on the distribution system performance.
Abstract: In this paper a two stage Grasshopper Optimization Algorithm (GOA) based Fuzzy multiobjective approach is proposed for optimum sizing and placement of Distributed Generations (DGs), Shunt Capacitors (SCs) and Electric Vehicle (EV) charging stations for distribution systems. In the first stage Fuzzy GOA approach is used for optimum sizing and allocation of DGs and SCs for improving the substation power factor, real power loss reduction and voltage profile improvement of the distribution system. In the second stage distribution system integrated with DGs and SCs is considered and fuzzy GOA approach is used for identifying optimum locations for EV charging stations and number of vehicles at the charging stations. EV battery charging load models are developed from the Lithium ion battery charging characteristic curves for load flow analysis. Simulation results are shown to show the advantages of fast converging properties of GOA over GA and PSO techniques. Simulation results are demonstrated on 51 bus and 69 bus distribution networks to show the advantages of proposed methodology compared to conventional objective based simultaneous optimization approach. The effect of EV load growth and the effect of uncertainties in DGs and distribution system load are shown on the distribution system performance.
107 citations
TL;DR: In this article, the authors discuss the phenomena by which geomagnetic induced currents are produced in power systems, the system and transformer modeling necessary for representing the effects, and the results of load-flow studies made with GIC present in a large interconnected power system in the northern United States and Canada.
Abstract: Large transient fluctuations in the earth's magnetic field can produce quasi-dc currents in electric power systems. These geomagnetically-induced currents (GIC's) cause half-cycle saturation in power transformers resulting in increased transformer var requirements. This paper discusses the phenomena by which GIC's are produced in power systems, the system and transformer modeling necessary for representing the effects, and the results of load-flow studies made with GIC present in a large interconnected power system in the northern United States and Canada. Results of the studies are compared with data recorded during a geomagnetic storm.
106 citations
TL;DR: In this article, the authors defined a dimensionless stability margin which lies between one and zero (steady state in- stability) and is easily computed from a load flow, where the margin of torque is defined as the least change in power flows that will cause instability.
Abstract: The flow function of a power system is the vector of node powers expressed in terms of the node angles The Jacobian is the matrix of partial derivatives of the flow vector with respect to the angle vector The ratio of the determinant of the Jacobian to the value which it has when the node angles are set to zero is a dimensionless stability margin which lies between one and zero (steady-state in- stability) and is easily computed from a load flow The margin of torque is the least change in power flows that will cause instability Maximizing the torque margin or maximizing the stability margin with a load constraint yields the optimum dispatching change to maximize security
106 citations