Models for conductor size selection in single wire earth return distribution networks

The use of the ground as the current return path often presents planning and operational challenges in power distribution networks. This study presents optimization-based models for the optimal selection of conductor sizes in Single Wire Earth Return (SWER) power distribution networks. By using mixed integer non-linear programming (MINLP), models are developed for both branch-wise and primary-lateral feeder selections from a discrete set of overhead conductor sizes. The models are based on a mathematical formulation of the SWER line, where the objective function is to minimize fixed and variable costs subject to constraints specific to SWER power flow. Load growth over different time periods is considered. The practical application is tested using a case study extracted from an existing SWER distribution line in Namibia. The results were consistent for different network operating scenarios

Transmission Investment Coordination using MILP Lagrange Dual Decomposition and Auxiliary Problem Principle

This paper considers the investment coordination problem for the long term transmission capacity expansion in a situation where there are multiple regional Transmission Planners (TPs), each acting in order to maximize the utility in only its own region. In such a setting, any particular TP does not normally have any incentive to cooperate with the neighboring TP(s), although the optimal investment decision of each TP is contingent upon those of the neighboring TPs. A game-theoretic interaction among the TPs does not necessarily lead to this overall social optimum. We, therefore, introduce a social planner and call it the Transmission Planning Coordinator (TPC) whose goal is to attain the optimal possible social welfare for the bigger geographical region. In order to achieve this goal, this paper introduces a new incentive mechanism, based on distributed optimization theory. This incentive mechanism can be viewed as a set of rules of the transmission expansion investment coordination game, set by the social planner TPC, such that, even if the individual TPs act selfishly, it will still lead to the TPC's goal of attaining overall social optimum. Finally, the effectiveness of our approach is demonstrated through several simulation studies

A heuristic model for planning of single wire earth return power distribution systems

G. Bakkabulindi, M. R. Hesamzadeh, M. Amelin, I. P. Da Silva, and E. Lugujjo - A Heuristic Model for Planning of Single Wire Earth Return Power Distribution Systems - The IASTED International Conference on Power and Energy Systems and Applications, PESA, Pittsburgh, USA 7-9 November 2011The planning of distribution networks with earth return is highly dependent on the ground's electrical properties. This study incorporates a load flow algorithm for Single Wire Earth Return (SWER) networks into the planning of such systems. The earth's variable conductive properties are modelled into the load flow algorithm and the model considers load growth over different time periods. It includes optimal conductor selection for the SWER system and can also be used to forecast when an initially selected conductor will need to be upgraded. The planning procedure is based on indices derived through an iterative heuristic process that aims to minimise losses and investment costs subject to load flow constraints. A case study in Uganda is used to test the model's practical application

The economics of electricity markets

With the transition to liberalized electricity markets in many countries, the shift to more environmentally sustainable forms of power generation and increasing penetration of electric vehicles and smart appliances, a fundamental understanding of the economic principles underpinning the electricity industry is vital. Using clarity and precision, the authors successfully explain economic theory of all liberalized electricity market types from a cross-disciplinary engineering and policy perspective. No prior engineering knowledge or economics expertise is assumed in introducing key ideas such as nodal pricing, optimal dispatch and efficient pricing or in extending those models to areas including investment, risk management and the handling of contingencies. Key features: Comprehensively covers the principles of all liberalized electricity market types, including the US, Europe, New Zealand and Australia. Provides up to date coverage of research and policy iss es, including design of financial transmission rights, modeling of market power, problems of regional pricing, and design of distribution pricing to facilitate Smart Grid. Spans introductory material to cutting-edge thinking on risk-management and short-run dispatch. Supports independent learning and teaching with worked examples and problems, enabling the reader to test and further deepen their understanding, whilst also promoting their insight and intuition. Solutions to problems and figures are hosted on a companion website. This ground-breaking text is an indispensable resource for the next generation of engineers, economists and policy-makers in or preparing to enter the electricity sector. Graduate students in electrical engineering and economics will benefit from the breadth of material and detailed, economically precise presentation

The TC-PSI indicator for forecasting the potential for market power in wholesale electricity markets

Wholesale electricity market regulators have long sought a simple, reliable, transparent indicator of the likely impact of wholesale market developments on the exercise of market power. Conventional indicators, such as the Pivotal Supplier Indicator (PSI) and the Residual Supply Index (RSI) cannot be extended to apply to meshed transmission networks, especially when generating companies hold a portfolio of generating units at different locations on the network. This paper proposes a generalisation of these standard measures termed the 'Transmission-Constrained Pivotal Supplier Indicator (TC-PSI)'. The TC-PSI of a generating company is defined as the maximum must-run generation for any subset of generating plant while allowing for strategic operation of other plant in the portfolio. We illustrate the use of the TC-PSI using a five-node model of the Australian NEM

A forward heuristic procedure for transmission planning in restructured electricity market

Abstract--The worldwide trend for restructuring of electric industry including generation, transmission, and distribution sectors has caused dramatic changes in operation and planning procedures of the power system. Under restructured electricity market environment, identifying a minimum-cost plan under particular constraints is not sufficient any more; other aspects such as market efficiency and environmental concerns are of equal importance as the cost minimisation objective along with more uncertainties. In this context, network augmentation plays a vital role in providing a full competitive environment for market players. This paper presents a novel forward heuristic algorithm to select the most effective expansion options based on a set of sensitivity indices which takes in to account the construction cost and market efficiency. The proposed method has been applied on a 6- bus test system for verifying its effectiveness

The TC-PSI indicator for forecasting the potential for market power in wholesale electricity markets

Wholesale electricity market regulators have long sought a simple, reliable, transparent indicator of the likely impact of wholesale market developments on the exercise of market power. Conventional indicators, such as the Pivotal Supplier Indicator (PSI) and the Residual Supply Index (RSI) cannot be extended to apply to meshed transmission networks, especially when generating companies hold a portfolio of generating units at different locations on the network. This paper proposes a generalisation of these standard measures termed the "Transmission-Constrained Pivotal Supplier Indicator (TC-PSI)". The TC-PSI of a generating company is defined as the maximum must-run generation for any subset of generating plant while allowing for strategic operation of other plant in the portfolio. We illustrate the use of the TC-PSI using a five-node model of the Australian NEM.Market power Pivotal supplier indicator Merger analysis