Z-bus loss allocation

2004 International Conference on Power System Technology, 2004. PowerCon 2004., 2004

This paper presents a methodology based on the Kirchhoff's circuit laws, and transaction power flow analysis for unbundling and allocating transmission losses to the participants of a pool-based electricity markets. From a solved load flow and using the basic network equations and not make any simplifying assumptions a new, simples and transparent branch loss formula in injections currents terms of each bus or market participant is derived. It natural separation explicitly expresses the loss allocation at each system branch pertaining to individual bus or market participant. Then, the proposed methodology provides branch unbundling and nodal allocating of transmission losses among power market participants. Extensions and strategies considering unsubsidized loss allocation and loss allocation based on a predefined proportion are also included. Several important aspects related with the allocation fairness and transparency are illustrated and compared by numerical applications with a 4-bus system. Index Terms-Loss allocation, pool-based electricity markets, power flow, transmission losses, transmission open access.

This paper proposes a systematic method to allocate the power flow and loss for deregulated transmission systems. The proposed method is developed based on the basic circuit theories, equivalent current injection and equivalent impedance. Four steps are used to trace the voltages, currents, power flows, and losses contributed by each generator sequentially. Using this method, the real and reactive power on each transmission lines and their sources and destinations can be calculated. The loss allocation of each line, which is produced by each generator, can also be obtained. Test results show that the proposed method can satisfy the power flow equation, the power balance equation and the basic circuit theories. Comparisons with previous methods are also provided to demonstrate the contributions of the proposed method.

IEEE Transactions on Power Systems, 2006

This paper presents a methodology based on the circuit theories for unbundling and allocation of transmission losses among the participants of a pool-based electricity market. Starting from a known operation point and using the basic network equations without additional assumptions, an expression of the branch losses based on nodal current injections is derived. Since the power flow equations and circuit theories are satisfied, the methodology turns explicit, in a natural way, separating the losses at each system branch and assigning the responsibility to the respective market participants. It means that the loss allocation of each branch, which is produced by each generator and consumer, is obtained. Extensions and strategies considering unsubsidized and predefined proportion-based loss allocation as well as issues related with the allocation fairness and transparency are also included. Comparisons with previous methods and validation tests of the proposed method are reported by using the IEEE Reliability Test System.

The proliferation of transactions coupled with the unbundling of services has created a need to evaluate the allocation of ancillary services among the transactions. The focus of this paper is on the compensation of loss service. Loss allocation is of importance in a competitive electricity marketplace for providing a priori information to transacting entities on the costs involved. We formulate the power flows in a network as an explicit function of the amounts of transactions between selling and buying entities. We develop a scheme based on the physical flows in the network to evaluate the losses associated with each transaction. The loss allocation scheme proposed makes detailed use of the mathematical model expressing flows in terms of transaction amounts. An important property of the proposed allocation scheme is its robustness. In addition, the mechanism can evaluate losses for any subset of transactions without requiring the complete information on all the transactions. Numerical tests of several networks including the 57-, 118-and 300-bus IEEE systems show that the scheme is effective in providing a physically meaningful allocation of losses. A summary of some numerical studies is given. Directions for future work are discussed.

2003

Transmission losses are a significant component of the amount of power to be generated in order to meet the power demand.

2007 IEEE Lausanne Power Tech, 2007

This paper presents a methodology for transmission loss allocation in pool markets, based on circuit laws, proportional sharing and superposition principles. The problem is divided in two parts: the first one considers the operation scenarios and the other the loads supply via transmission paths from generators. A five-bus system has been used to demonstrate and compare the performance of the proposed framework with results provided by previous works.

2017

In this paper, a method is proposed to assign transmission losses costs in pool-based electricity markets. This method is based on using the impedance matrix of the network and partial derivatives of the active power losses respect to bus currents coefficients. After performing load flow equations, the losses of each bus are calculated using the impedance matrix of the network and the injected currents from each bus. These losses are properly and fairly shared between network buses for fair loss allocation, in proportion to partial derivatives of the active power losses respect to bus currents coefficients. Finally, this method has been tested on a benchmark IEEE 14-bus network and the results are compared with the other existing methods.

2014

Restructuring of Electricity supply industry introduced many issues such as transmission pricing, transmission loss allocation and congestion management. Many methodologies and algorithms were proposed for addressing these issues. In this paper a power flow tracing based method is proposed which involves Matrices methodology for the transmission usage and loss allocation for generators and demands. This method provides loss allocation in a direct way because all the computation is previously done for usage allocation. The proposed method is simple and easy to implement in a large power system. Further it is less computational because it requires matrix inversion only a single time. Results are shown for the sample 6 bus system and IEEE 14 bus system.

During the last fifty years, the field of Electrical Engineering has become very diversified and is much broader in scope now than ever before. With emerging new topic areas, ranging from microelectro-mechanics to light-wave technology, the number of Electrical Engineering courses available to students has considerably increased. In order to keep pace with the progress in technology, we must adopt to provide the students with fundamental knowledge in several areas. Power System Engineering is one of such areas. This book describes the various topics in power system engineering which are normally not available in a single volume. To briefly review the content of this text, Chapter 1 provides an introduction to basic concepts relating to structure of power system and few other important aspects. It is intended to give an overview and covered in-depth. Chapters 2 and 3 discuss the parameters of multicircuit transmission lines. These parameters are computed for the balanced system on a per phase basis. Chapter 4 addresses the steady-state and transient presentation and modeling of synchronous machine. Chapter 5 deals with modeling of components of power system. Also, the per unit system is presented, followed by the single line diagram representation of the network. Chapter 6 thoroughly covers transmission line modeling and the performance and compensation of the transmission lines. This chapter provides the concept and tools necessary for the preliminary transmission line design. Chapters 7 presents comprehensive coverage of the load flow solution of power system networks during normal operation. Commonly used iterative techniques for the solution of nonlinear algebraic equation are discussed. Different approaches to the load flow solution are described. Chapters 8, 9 and 10 cover balanced and unbalanced fault analysis. The bus impedance matrix by the Z BUS building algorithms is formulated and employed for the systematic computation of bus voltages and line currents during faults. Symmetrical components technique are also discussed that resolve the problem of an unbalanced circuit into a solution of number of balanced circuits. Chapter 11 discusses upon the concepts of various types of stability in power system. In particular, the concept of transient stability is well illustrated through the equal area criterion. Numerical solution for the swing equation is also defined. Chapter 12 deals with AGC of isolated and interconnected power systems. Derivation of governor and turbine models are presented. Both steady-state and dynamic analysis are presented. Treatment of generation rate constraint in mathematical model is also discussed. Multiunit AGC system is discussed. Chapter 13 discusses the AGC in restructured environment. Block diagram representation of AGC system in restructured enviornment is discussed and equivalent block diagram is presented for easy understanding. Different case studies are presented. Chapter 14 deals with corona loss of transmission lines. All mathematical derivations are presented in detail and the factors affecting the corona are discussed. Chapter 15 deals with sag and tension analysis of transmission lines. Catenary and Parabolic representation are presented. Effect of wind pressure and ice coating on conductors are considered and mathematical derivations are presented. Chapter 16 deals with optimal system operation. A rigorous treatment for thermal system is presented. Gradient method for optimal dispatch solution is presented. Derivation of loss formula is also presented. Every concept and technique presented in each chapter is supported through several examples. At the end of each chapter, unsolved problems with answers are given for further practice. At the end a large number of objective type questions are added to help the students to test himself/herself. As listed in the bibliography at the end of this book, several excellent text are available which will help the reader to locate detailed information on various topic of his/ her interest. After reading the book, students should have a good perspective of power system analysis. The author wishes to thank his colleagues at I.I.T., Kharagpur, for their encouragement and various useful suggestions. My thanks are also due to New Age International (P) Limited, especially its editorial and production teams for their utmost cooperation in bringing out the book on time. Last, but not least, I thank my wife Shanta for her support, patience, and understanding through the endeavour. I welcome any constructive criticism and will be very grateful for any appraisal by the reader. Preface vii 1. Structure of Power Systems and .ew Other Aspects .ig. 1.4: Load curve of Ex1.1. Units generated during 24 hours = (2 × 1.2 + 1 × 2 + 3 × 3 + 2 × 1.5 + 4 × 2.5 + 2 × 1.8 + 1 × 2

Electric Power Components and Systems, 2010

International Journal of Electrical Power & Energy Systems, 2012

In this paper, the transmission cost allocation problem is discussed in a deregulated electricity market. The proposed method is based on power flow equation. In this approach, first, the relation between the generator or load currents and the bus injection currents is defined using a power invariant matrix, then the active power flow through each line is expressed in terms of generator or load currents. A fourbus test system is used to explain how the proposed method allocates the cost of real power flow to generators or loads separately. The obtained results are compared with the conventionally adopted methodologies to defend easy implementation and effectiveness of the proposed method. The obtained results explicitly show that the proposed method is fitting and behaves in a physically fair manner. This method dominates the difficulties of conventionally used approaches, encouraging the economically optimal usage of the transmission facilities. A case study based on IEEE 24-bus test system is applied to assess the effectiveness of the cost allocation procedure.

Ieee Transactions on Power Systems, 2007

This paper addresses the problem of allocating the cost of the transmission network to generators and demands. A physically-based network usage procedure is proposed. This procedure exhibits desirable apportioning properties and is easy to implement and understand. A case study based on the IEEE 24-bus system is used to illustrate the working of the proposed technique. Some relevant conclusions are finally drawn.

Modeling, Identification and Control: A Norwegian Research Bulletin, 2003

This paper shows how MATPOWER, a MATLAB Power System Simulation Package can be used for optimal power flow (OPF) simulations. MATPOWER is a package of MATLAB files for solving power flow and optimal power flow problems. It is a simulation tool for researchers and educators which is easy to use and modify. An OPF simulation gives the active/reactive power generated and purchased at each bus and the nodal prices. The nodal prices are of special interest because they reflect the marginal generation and load at each bus (node). These prices are also called locational prices and are found to be the optimal prices, maximizing social welfare and taking transmission constraints into account. They can provide the right incentives to market players and to society. When transmission congestion is present this creates market inefficiency, since cheap distant generation may be replaced with more expensive local generation. We are especially interested in OPF as utilized by a centralized dispatcher, and we also describe the features relevant for the Norwegian and Nordic markets. We optimize three cases and analyze the economic consequences of different network topologies and transmission congestion.

International Journal of Electrical Power & Energy Systems, 2004

This paper focuses on the application of the Optimal Power Flow (OPF) to competitive markets. Since the OPF is a central decisionmaking tool its application to the more decentralized decision-making in the competitive electricity markets requires considerable care. There are some intrinsic challenges associated with the effective OPF application in the competitive environment due to the inherent characteristics of the OPF formulation. Two such characteristics are the flatness of the optimum surface and the consequent continuum associated with the optimum. In addition to these OPF structural characteristics, the level of authority vested in the central decision-making entity has major ramifications. These factors have wide ranging economic impacts, whose implications are very pronounced due to the fact that, unlike in the old vertically integrated utility environment, various market players are affected differently. The effects include price volatility, financial health of various players and the integrity of the market itself. We apply appropriate metrics to evaluate market efficiency and how the various players fare. We study the impacts of OPF applications in the Pool paradigm, with both supply and demand side explicitly modeled, and provide extensive numerical results on systems based on IEEE 30-bus and 118-bus networks. The results show the variability of nodal prices and the skew possible in different 'optimal' allocations among competing suppliers. Such variability in the results may lead to serious disputes among the players and the central decision-making authority. Directions for future research are discussed.