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In this paper, oligopolistic competition in a centralized power market is characterized by a multi-leader single- follower game, and formulated as a nonlinear programming (NLP) problem. An AC network is used to represent the transmission system, and is modelled using rectangular coordinates. The follower is composed of a set of competitive suppliers, demands and the system operator, while the leaders...
Summary form only given. This paper presents a fuzzy distribution power flow (FDPF) for weakly meshed balanced and unbalanced distribution system. Most of the earlier work in this area is for radial distribution systems. In the proposed method a matrix similar to Jacobian inverse is directly evaluated, in an efficient manner. The method can handle simultaneous presence of several uncertainties in...
Summary form only given. This paper presents closed-form steady-state, fundamental-frequency models of power electronic converter systems for coupling distributed resource (DR) units to the utility power grid. Based on the developed models, the paper introduces a two-step power flow analysis approach that accurately and efficiently represents electronically-coupled DR units. A feature of the proposed...
Summary form only given.This paper presents results from an analysis of voltage stability following severe contingencies in the PJM system. The analyses involved the use of steady-state (OPF) and short and long-term simulation tools. The results highlight the importance of adequate load modeling in assessing the performance of and solutions to voltage instability. UVLS is shown to be beneficial in...
Summary form only given. This paper proposes the use of an auxiliary gradient system to calculate the low-voltage solutions (LVSs) of the load flow equations of an electrical power system. It shows that the equilibrium points of that associated auxiliary dynamical system are the solutions of the load flow equations. In such a manner, the paper proposes to find the LVSs by calculating the equilibrium...
Summary form only given. The definitions of power, and related quantities such as apparent power and reactive power, in sinusoidal and non-sinusoidal situations are reviewed. These definitions are compared with the physical mechanisms for the transfer of power in an electrical circuit by means of the Poynting Vector. Real power flows into and out of resistors; inductors and capacitors are used to...
A wound rotor induction machine can be used in a variable frequency transformer (VFT) to allow interconnection of two power grids that run asynchronously to each other. The transfer of power across the air gap of the machine is controlled by variation of the torque that is applied to the shaft of the VFT. The magnitude of the power transfer is directly proportional to the shaft torque while the direction...
This paper reports on experience to date in studying and designing interconnections to existing power systems for the VFT application at Linden, New Jersey between the New York ISO and PJM control areas. Since the VFT is by definition a transmission connection device, it will have two connections to existing systems which are often located in areas controlled by different grid operators. Included...
Reliable operation of power system is fundamental to the on-going industry reform. This paper presents the result of marginal power flow evaluation performed on Korean power system using two commercial software packages: Physical and Operational Margins (POM V. 2.2) and probabilistic reliability assessment (PRA V. 3.1), respectively. The case study of Korea power system for year 2006 data shows that...
Embedded generators are expected to play an increasingly important role in future energy supply. They could potentially benefit networks from loss reduction and deferred or delayed investment. Equally, they can increase network investment through inappropriate siting, potentially leading to expensive network upgrading and expansion. This cost/benefit of embedded generator is not reflected by any of...
In this paper, we present recent representative studies about technical and economical considerations for the power system interconnection in Northeast Asia (NEA). These activities on interconnection between countries or areas in a NEA have been considered and presented from many sides including considering political and economical situations. In South Korea, recent studies of power system interconnection...
Interregional reactive power flows are rarely a decisive issue for transmission system utilities operating on interconnected systems. However, economic constraints and increasing stress on interconnection lines may lead to recurrent conflicts, which could be avoided with a better inter-utility coordination. This paper exposes a method for evaluating the impact of multi-utility MVAr scheduling. This...
A computationally simple algorithm is developed for studying the load shedding problem in emergencies where an ac power flow solution cannot be found for the stressed system. The proposed algorithm is divided into two sub-problems: restoring solvability sub-problem and improving voltage stability margin (VSM) sub-problem. Linear optimization (LP)-based optimal power flow (OPF) is applied to solve...
A new method for probabilistic power flow considering transmission network contingency is proposed for the purpose of removing the unrealistic assumptions of conventional analytical PLF techniques. Because any component failure in a transmission network will change the system configuration, the calculation of power flow distribution needs to consider those contingencies. The method proposed in this...
This paper proposes a new method for stochastic load flow (SLF) by using deterministic sampling based on sigma-point selection. In stead of conducting time-consuming Monte Carlo simulation, the proposed method can efficiently estimate the mean and covariance of state variables and branch power flow by conducting only 2k+ chosen deterministic power flow for a power system with k normally distributed...
This paper presents a new approach to the resolution of the optimal power flow problem. In this approach the inequality constraints are treated by the modified barrier and primal-dual logarithmic barrier methods. The inequality constraints are transformed into equalities by introducing positive auxiliary variables, which are perturbed by the barrier parameter. A Lagrangian function is associated with...
This panel summary will provide an overview of distribution system analysis issues emanating from the integration of distributed generation. Specifically, impacts on models and subsequent analysis tools will be assessed.
The object of this paper is to study the risk of long- term bilateral contract in the deregulated power system. A model for long-term bilateral contract pricing with risks of congestion is presented. The negotiated income, variable fuel cost, investment depreciation, and congestion payment during the whole contract period are involved in this model. Based on the principle of no-arbitrage, the negotiated...
Transmission congestion management is critical for reliable system operation by keeping the system within the security constraints. In this paper we examine an efficient congestion management system compatible with evolving market environment; the key is building an information exchange protocols between the independent system operator (ISO) and market participants (MPs) that integrate market-based...
This paper proposes two new methods for congestion management. One is the concept of line flow sensitivities for line reactances and the other is a congestion management method using these sensitivities. The proposed sensitivities are based on the DC method. The proposed congestion management method, whose purpose is to relieve congestion without influencing transactions, is carried out by changing...
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