Elimination Methods for Load-Flow Studies

Ness, J. E. Van; Griffin, John H.

doi:10.1109/aieepas.1961.4501030

Cited by 61 publications

(19 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Conventional power flow analysis [31][32][33] aims at determining state variables (e.g., voltage and phase angle at PQ buses and power flow in the feeders) in a network based on given input parameters (e.g., active-reactive power at PQ buses and phase angle at the slack bus). In such analysis, there is no free variable, and therefore it is carried out on the basis of simulation.…”

Section: Problem Formulationmentioning

confidence: 99%

A Survey of Real-Time Optimal Power Flow

et al. 2018

View full text Add to dashboard Cite

There has been a strong increase of penetration of renewable energies into power systems. However, the renewables pose new challenges for the operation of the networks. Particularly, wind power is intermittently fluctuating, and, therefore, the network operator has to fast update the operations correspondingly. This task should be performed by an online optimization. Therefore, real-time optimal power flow (RT-OPF) has become an attractive topic in recent years. This paper presents an overview of recent studies on RT-OPF under wind energy penetration, offering a critical review of the major advancements in RT-OPF. It describes the challenges in the realization of the RT-OPF and presents available approaches to address these challenges. The paper focuses on a number of topics which are reviewed in chronological order of appearance: offline energy management systems (EMSs) (deterministic and stochastic approaches) and real-time EMSs (constraint satisfaction-based and OPF-based methods). The particular challenges associated with the incorporation of battery storage systems in the networks are explored, and it is concluded that the current research on RT-OPF is not sufficient, and new solution approaches are needed.Energies 2018, 11, 3142 2 of 20 time. However, the incorporation of BSSs into the network leads to dynamic state operations and thus introduces dynamic model equations to the OPF, which makes the problem more complex to solve. This complexity is due to the fact that the dynamic optimization is described by differential/difference equations, whereas static optimization requires only algebraic equations [30].Another issue is that the REG rate is uncertain. It means their output cannot be forecasted accurately, and there may be discrepancies between the forecasted and actually realized values. The uncertainties can lead to constraint violations and thus safety problems if they are not handled properly. Therefore, deterministic OPF methods are not suitable for the real operation of the networks, or their solutions need further modifications before realization. Besides, owing to fast fluctuating REG, in particular wind power, the network operators need to fast update-i.e., in real-time-the operation strategies correspondingly, in order for the network to operate economically and in its feasible region. Therefore, the real-time energy management systems (RT-EMSs) have attracted increasing interest from many researchers. In this paper, we classify the RT-EMSs into two main categories: (1) constraint satisfaction-based RT-EMSs, and (2) OPF-based RT-EMSs. The former can satisfy the technical constraints of the network in real time, but the solutions may not be optimal. The latter provides optimal solutions in real time while satisfying the constraints. It is noted that the technical constraints could be different for these two categories, depending on the components of the network (details can be seen in Section 2).The remainder of the paper is organized as follows: Section 2 provides the general formulation of OPF...

show abstract

Section: Problem Formulationmentioning

confidence: 99%

A Survey of Real-Time Optimal Power Flow

et al. 2018

View full text Add to dashboard Cite

show abstract

“…This load flow problem can be solved by the Newton's method using a set of nonlinear equations to express real and reactive powers in terms of bus voltages [4,12,14]. Substituting I p from equation (2.2) into equation (2.3) results in…”

Section: Interval Load Flow Problemmentioning

confidence: 99%

Power Flow with Load Uncertainty

Barboza¹,

Dimuro²,

Reiser³

2004

TEMA - Tendências Em Matemática Aplicada E Computacional

View full text Add to dashboard Cite

Abstract. This paper presents a methodology to solve load flow problems in which the load data are uncertain due to measurement errors. In order to deal with those uncertainties we apply techniques of Interval Mathematics. The algorithm uses the Interval Newton's method to solve the nonlinear system of equations generated by the problem. The implementation was performed in the Matlab environment using the Intlab toolbox. In order to assess the performance of the proposed algorithm, the method was applied to hypothetical electric systems. In this paper, we present results for a three-bus network.

show abstract

“…We refer to [65] for more details on all six versions of the Newton power flow method. In [65], the existing versions of the Newton power flow method [8,18,66] are compared with the newly developed/improved versions of the Newton power flow method (Cartesian power mismatch, complex power mismatch, polar current mismatch, Cartesian current mismatch, and complex current mismatch) for single-phase power flow problems in balanced transmission and distribution networks. It is concluded in [65] that the newly developed/improved versions have better performance than the existing versions of the Newton power flow method.…”

Section: Introductionmentioning

confidence: 99%

Newton Power Flow Methods for Unbalanced Three-Phase Distribution Networks

2017

View full text Add to dashboard Cite

Two mismatch functions (power or current) and three coordinates (polar, Cartesian and complex form) result in six versions of the Newton-Raphson method for the solution of power flow problems. In this paper, five new versions of the Newton power flow method developed for single-phase problems in our previous paper are extended to three-phase power flow problems. Mathematical models of the load, load connection, transformer, and distributed generation (DG) are presented. A three-phase power flow formulation is described for both power and current mismatch functions. Extended versions of the Newton power flow method are compared with the backward-forward sweep-based algorithm. Furthermore, the convergence behavior for different loading conditions, R/X ratios, and load models, is investigated by numerical experiments on balanced and unbalanced distribution networks. On the basis of these experiments, we conclude that two versions using the current mismatch function in polar and Cartesian coordinates perform the best for both balanced and unbalanced distribution networks.

show abstract

Elimination Methods for Load-Flow Studies

Cited by 61 publications

References 3 publications

A Survey of Real-Time Optimal Power Flow

A Survey of Real-Time Optimal Power Flow

Power Flow with Load Uncertainty

Newton Power Flow Methods for Unbalanced Three-Phase Distribution Networks

Contact Info

Product

Resources

About