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Variable-speed wind turbines with full power processing capability are the new technology trend for large wind power plants. In this type of turbine, there is an interface between the generator and the utility grid. In this paper, we investigate the characteristics of a variable-speed wind turbine connected to a stiff grid or a weak grid, the role of reactive power compensation in optimizing the operation...
This paper integrates the natural gas and electricity networks in terms of power and gas optimal dispatch. It shows the fundamentals of natural gas network modeling including pipelines and compression stations. It also describes the equality constraint that models the energy transformation between gas and electric networks. A mathematical model of this problem is formulated as an optimization problem...
An open integration framework of heterogeneous power system information based on agent technology is proposed in this paper. Fundamental problems of information integration have been studied to solve the bottleneck of implementing such system within the very field of power system whose stability depends on its information consistency and reliability. Due to the characteristics of agent system, our...
Since there exist significant time delays in the information of phasor measurement unit (PMU) and wide area measurement system (WAMS), it is an important issue to properly evaluate the influence of time delay in power system stability study and controller design. In this paper, we mainly focus on the determination of the maximum time delay that system can sustain without losing small signal stability...
Slow coherency analysis is used to effectively determine the slowly coherent generator groups among weak connections for any given power system. A novel graphic theoretic method is proposed in this paper to simplify a large scale power system into a smaller network without losing optimal solutions. A multi-level recursive bisection graph partition method is employed to partition the reduced network...
This paper develops an energy loss formula for electrical networks. In this formula, electric components' energy losses in a given duration are divided into three parts. The primary energy losses can be quantified by the power flow calculation with average loads at nodes, and its linear and quadratic correction value can be produced by using an approximate algorithm whose accuracy is determined by...
Adaptive damping controller is a challenging issue in the area of power system stability and control because of the difficulties in identification and design in real system. In this paper, a heuristic adaptive HVDC supplementary damping controller (AHDC) is designed based on online Prony analysis. Parameters of the controller are tuned according to the damping ratios of the weak-damped inter-area...
We investigate the influence of non-differential components to the power system small signal stability region in this paper. A method named unified expression function (UEF) is introduced to describe the piecewise, continuous and non- differential function in the small signal stability study. It converts non-differential points of the original function to poles of the UEF's derivative function. Then...
The concept of "power flow tracing" between generators and transmission has been discussed for determining wheeling rates of new users under deregulated environments. In this paper, we focus on "generalized generation distribution factors" and "modified power transfer distribution factors", which are distribution factors for tracing, and propose a new method of evaluating...
A wind farm typically consists of a large number of individual wind turbine generators (WTGs) connected by an internal electrical network. To study the impact of wind farms on the dynamics of the power system, an important issue is to develop appropriate wind farm models to represent the dynamics of many individual WTGs. This paper presents various dynamic models, including a detailed model and three...
Electrical phenomena in power systems tend to exhibit higher nonlinearity, because more efficient operation accompanies severer power transfer. In such situations, there might exist some limitation to the use of conventional linear control design scheme due to the nonlinearity of power systems. As for consideration of the nonlinearity, we have developed a nonlinear stability analysis method based...
This paper presents a new algorithm called equal embedded algorithm is used to solve large scale economic load dispatch problem with prohibited zones and losses. The algorithm involves the selection of lambda values, then the output power expressions of generating unit are obtained in terms of the lambda by interpolation and finally the lambda is evaluated from the power balance equation by Muller...
Power infrastructure vulnerabilities are growing due to liberalization of national markets, growing demand, and hectic transactions among national, regional, and local systems, resulting in an infrastructure that is more complex and difficult to manage. While innovative information and communication technologies (ICT) offer a chance to better cope with this increased complexity, such technologies...
With the wide application of synchronized phase measurement unit (PMU) in power system, the wide-area measurement system (WAMS) has enabled the use of a combination of measured information from remote location for global control purpose. However, the impact of time delays introduced by remote information's transmission in WAMS has to be considered, and the closed-loop power systems need be modeled...
This paper presents a pricing model considering the simultaneous interaction of pool, bilateral and reserve markets in a power system. The model is adapted to work through a 'pay as bid' (PAB) pricing approach that is currently being considered as an option for pricing in some actual systems. The combined market is settled through an AC optimal power flow (OPF) that accounts for power generation (pool...
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