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Time of use pricing strategy can not only reduce the load fluctuation but also improve the power system reliability. Generally, before carrying out a time of use pricing optimization, it needs to perform a period partition optimization for dividing peak‐valley periods. In existing researches, however, the period partition optimization and the time of use pricing optimization are implemented independently. Although the output of period partition optimization is used as the input of time of use pricing optimization, the bidirectional feedback effect between period partition optimization and time of use pricing optimization is not considered, which will lead to the existing time of use pricing optimization may not be the globally optimal solution. Therefore, this paper investigates a new optimization method for time of use pricing optimization with the consideration of bidirectional feedback effect, establishes a comprehensive customer satisfaction degree model considering the customer load proportion coefficient, and defines an elastic cofactor to describe the electricity price response difference of multiple types of customers. The Roy Billinton test system is used to verify the correctness and effectiveness of the proposed method in this paper. [ABSTRACT FROM AUTHOR]

The implementation of powerline communication (PLC) on single-wire earth return (SWER) grids requires high-frequency earth path characterization. The empirical determination of these characteristics is not practical for large grids. Analytical expressions may be used to estimate the high-frequency characteristics of earth paths; however, this paper shows that this approach can lead to errors when modeling line-to-earth path PLC channels. Therefore, a hybrid empirical/analytical earth path characterization method, based on heuristic correlations of measurement results with a lossy capacitor model, is hereby proposed. Further measurements on an experimental SWER line using two types of conductors were carried out. The results indicate that narrowband PLC implementation on SWER grids is feasible, and that conductors with similar size and material composition may have similar high-frequency characteristics, regardless of the construction method used. The proposed earth path characterization method was verified by comparing measurements with simulations of frequency-dependent analytical and constant parameter hybrid, per-unit SWER transmission line models. [ABSTRACT FROM PUBLISHER]

European power markets have become more integrated and renewables have a significant effect on power prices and cross-border exchanges. This paper investigates empirically how the effects of renewables are affected by market expansion across two adjacent countries (France and Germany), based on market data and proprietary data on book orders. We find that wind production lowers power prices on average and increases volatility, not only domestically but also across borders. Using multiple counterfactuals, we examine how our results depend on the level of interconnection and find that further interconnection capacity would decrease price volatility in both countries since the benefits of a larger market would outweigh the contagion effects of volatility. Our findings have important policy implications as they demonstrate the need to coordinate support policies for renewables and policies to support transmission capacity expansion in order to mitigate the impact of volatility on power prices in neighboring power markets. [ABSTRACT FROM AUTHOR]

We propose a stochastic mixed integer optimization model to optimally size a solar power system and its battery storage for residential and nonresidential customers of electric power. The objective function of the model is to minimize the total cost associated with solar power system investments and the grid provided electric power over a planning horizon. We consider the uncertainty associated with solar radiation, load, and electricity price in the form of probabilistic scenarios. The model can be used with different grid pricing programs and under no net metering or net metering programs, respectively. A numerical example and its parametric analyses are used to demonstrate the efficacy of the model and develop some insights into optimal sizing of a battery storage enabled solar system. The analyses show the size of the solar system is influenced by the labor cost and the load size whereas the size of the battery storage is sensitive to the load size and the battery cost. Moreover, we find the optimal number of solar panels/batteries is larger under the net metering program than under no net metering program. [ABSTRACT FROM AUTHOR]

In this century, problems such as the scarcity of fossil fuel resources and related environmental contamination have led to the emergence of new energy systems based on renewable energy resources. In this paper, an optimal planning approach is proposed based on 100% renewable energy system (RES) for a residential house. In respect to renewable resources potential in the site location and electrical demand, the best combination of resources is chosen based on minimum energy supply cost and maximum reliability. Furthermore, different scenarios are suggested by considering different levels of capacity shortage (CSH) and unmet electricity load (UEL) percentage. As a case study, the real electricity consumption data for a single family household is considered in Hesarak, Tehran, Iran. The final optimal solution for this 100% RES with the objective function of cost minimization and reliability constraint include 4 kW PV, 2 kW wind turbine, 4 kW converter and 6 battery strings. This scenario with CSH of 1.1% and UEL of 0.9% has the net present cost of 20,527 $ that while having low cost, the reliability of this system is also good compared to other scenarios. [ABSTRACT FROM AUTHOR]

The cooperation of multiple networked microgrids (MGs) can alleviate the mismatch problem between distributed generation and demand and reduce the overall cost of the power system. Energy management with direct energy exchange among MGs is a promising approach for improving energy efficiency. However, existing methods on microgrid cooperation usually overlook the underlying distribution network with operating constraints (e.g., voltage tolerance and power flow constraints). Hence the results may not be applicable to actual systems. This paper studies the energy management problem of multiple MGs that are interconnected by both the direct current (DC) energy exchange network and the alternating current (AC) traditional distribution networks. In our problem, each MG is equipped with renewable energy generators as well as distributed storage devices. In order to handle the non-convex power flow constraints, we exploit the recent results of the exact optimal power flow (OPF) relaxation method which can equivalently transform the original non-convex problem into a second-order cone programming problem and efficiently determine the optimal solution successfully. The objective of our problem is to minimize the overall energy cost in a distribution network consisting of multiple MGs, with the practical operating constraints (e.g., power balance and the battery’s operational constraints) explicitly incorporated. Considering the privacy and scalability, we propose a distributed algorithm with convergence assurance based on the alternating direction method of multipliers (ADMM). We also implement our method based on the model predictive control (MPC) approach in order to handle the forecasting errors of the renewable energy generation. Simulations are made for different MG exchange topologies on three radial distribution network testbeds. Numerical results demonstrate that certain topologies are more favorable than others, and the cooperation strategy for the energy exchange is significantly affected by the MGs’ locations in the distribution network. [ABSTRACT FROM AUTHOR]

In this paper, an approach for placement of voltage regulators (VRs) in traditional distribution systems by considering a local controller model is presented. The main aims of this paper are controlling the voltage level in its permitted range and decreasing the costs imposed to the distribution system companies, such as costs that stem from power losses, VRs’ investment and maintenance. Genetic algorithm (GA) has been used as a tool to determine the number, location and rated power of VRs. Since in traditional distribution systems, tap position determination of VRs is achieved by local controllers, local controller model is established to determine tap operations. A 70-bus distribution system is considered to prove the value of the presented approach. Effectiveness of the proposed approach and ineffectiveness and infeasibility of conventional approaches are presented in numerical studies. The presented approach allowed to eliminate voltage violation in all load conditions and a reduction of power losses of about 6% for the maximum load level. [ABSTRACT FROM AUTHOR]

The Midwest is the largest Brazilian agricultural region, far from major power production units. The availability of energy close to consumption, or distributed generation (DG), can reduce distribution costs and losses. We verified the possibility of using electric power from sugarcane biomass to irrigate corn crops through interviews with sugarcane companies and farmers. Direct commercialization of energy from sugarcane biomass for irrigation is not viable due to energy subsidies received by irrigating farmers. Most sugarcane energy is sold into the national network, without considering its origin. DG has potential, but its development involves the increase of rural energy consumption, such as for irrigation. [ABSTRACT FROM AUTHOR]

The management of renewable and distributed energy resources is changing the way in which electric distribution systems are being operated. Many companies commonly create several custom system solutions to manage power distribution. The functions provided by these systems are network visualization, state estimation, system control and data acquisition, among others. Despite their relevance, many mid-size or small distribution companies have problems to install one of these solutions because they are either very expensive, incompatible, or limited by difficulties in data exchange. As a possible solution to this problem, this paper presents the development of a Distribution Management System (DMS) based on open source technology. This system combines four main components: OpenDSS-framework, ActiveMQ-broker, applications for visualizing and editing electrical network, and Common Information Model (CIM). The tool is part of Tenergia R&D project 1 This work is financed by R&D projects FITS 2013 – UREE10 – FONARSEC – Ministry of Science, Technology and Productive Innovation of Argentina, and PIDDEF 36/14 – Ministry of Defense of Argentina. 1 and has a collection of applications designed to monitor and control the distribution networks located in Argentina. [ABSTRACT FROM AUTHOR]

Electrical transmission lines in Alaska vary from overhead to submarine to underground installations. Analysis indicates that overhead transmission lines are the least expensive to build, ranging from $100 000 to $400 000/mile. Cost variability is influenced by pole spacing, pole heights, line ratings, river crossings, and the amount of work on energized power lines. Submarine lines and underground lines are substantially more expensive than overhead lines, ranging from less than $3 000 000 to more than $4 500 000/mile although there is some uncertainty in the datasets. When broken down by major cost components, the cost category including materials, construction, and installation comprises just over half of the total costs, with remaining costs distributed among the control system, substation, switchyard, road clearance, indirect costs, and contingencies. Operation and maintenance costs range from $2800/mile to $4200/mile, with an average of $3560/mile. Expected lifetimes are 20-30 years. In general, the transmission technology market is not as dynamic as other energy markets. Financing and initiatives to encourage interties may create bigger loads and economies of scale. [ABSTRACT FROM AUTHOR]

This article examines the use of publicly-available financial and operating data to benchmark distribution performance of U.S. IOUs. The authors describe a methodology addressing characteristics beyond IOU control commonly held to impact performance. Econometric analyses refute many commonly-held beliefs about the influence of various characteristics on various performance measures, and support other beliefs only weakly. The authors then apply appropriate adjustments quantified through regression analyses to create a distribution business performance ranking of U.S. IOUs. [ABSTRACT FROM AUTHOR]

The policy of net metering allows operators of residential- and commercial solar PV systems to sell surplus electricity back to their utility at the going retail rate. This policy has recently been criticized on the grounds that it provides a subsidy for residential and commercial solar installations, a subsidy that is paid for by all ratepayers. In response, public utility commissions have begun to take up this regulatory issue. This paper presents a theoretical and empirical analysis of the effects of net metering restrictions. We examine the impact that overage tariffs (OT) will have on the size of future residential PV investments. Overage tariffs credit electricity generated by the solar system, but not consumed by the household and thus transferred back to the utility, at a rate below the going retail electricity rate. Our calculations focus on three representative locations in the states of California, Nevada and Hawaii. We find that if overage electricity is credited at some rate set at or above the levelized cost of electricity (LCOE), there would be sufficient incentives for investors in residential solar PV to continue in the current mode of solar rooftop installations, even though the profitability of these investments might be reduced substantially. At the same time, we find that the LCOE is a tipping point insofar as overage tariffs set below that level would have a sharply negative effect on the individual size and overall volume of new rooftop installations. [ABSTRACT FROM AUTHOR]

This study aims to develop a new approach for design and evaluation of renewable energy sources-based energy supply system using different energy demand scenarios and an optimization model. To achieve this goal, we first generate six scenarios by the combination of different supply and demand options. We then develop a new optimization model for identifying the optimal system configuration by minimizing the total energy cost subject to various constraints. We apply the proposed approach to the design problem of energy system of Jeju Island, Korea. We evaluate the different scenario-based systems of Jeju Island using economic metrics including net present cost, levelized cost of energy and annual energy expenses. The sensitivity of major process and economic parameters, and different meteorological data on the annual energy expenses is also discussed. As a result, the levelized energy cost was estimated to range from 0.53 to 1.34 $/kWh according the examined scenarios. We analyzed that the centralized energy production by the hybrid use of wind and solar energy is the most affordable system. We also identified the key cost driver in the distributed and centralized energy production systems; i.e., the capital cost of the wind turbine and the energy storage facilities, respectively. [ABSTRACT FROM AUTHOR]

Few studies have been reported for the small scale LNG regasification units in power generation systems although many applied LNG cold utilization systems exist for the large scale regasification plants. Impact of the LNG cold utilization system is investigated for the micro cogeneration systems thermoeconomically. An exergy-cost matrix is generated for the systems, which then compared to the conventional micro cogeneration systems. Ambient air temperature and compressor pressure ratio are analyzed. The required work for the LNG pump is found to be neglected in overall cycle analyses. In the cogeneration case, the exergetic and energetic efficiencies are roundly two and three times higher than the single power generation case. The exergoeconomic factor is roundly 26.8% less in the LNG cold utilized system while the relative cost is 75% higher in the conventional case. The LNG cold utilization increases the levelized product costs about 1.7 times at the pressure ratio of 3.64. A graphic-based single objective optimization is conducted by determining unit product cost and exergetic efficiency as the objectives. The maximum relative unit product cost difference is found at 308.15 K while the minimum relative exergetic efficiency difference is at 288.15 K. We suggest system improvements through the thermoeconomic evaluation. [ABSTRACT FROM AUTHOR]

Despite their importance for the proper operation of both care and non-care services, there are no models in the literature analysing the choice of the most suitable maintenance strategy to be applied in electric power distribution systems in Health Care Organizations. This paper presents an innovative multicriteria which contributes to ensuring the best quality of care for the patient. The model integrates the Measuring Attractiveness by a Categorical Based Evaluation Technique approach with Markov chains to obtain the expected mean availability for different electric power distribution systems. The result is a full classification of the combination of maintenance policies and actions (redundancy), to be applied in power distribution systems. The model gives, as the most suitable maintenance strategy, a combination of corrective, preventive and predictive maintenance (thermal analysis). It is the first model produced and applied to a variety of electric power distribution systems responsible for supplying electrical energy to critical areas of the Health Care Organizations, such as operating theatres, intensive care units, paediatrics, general lighting and other specific areas. The result obtained is compared with the maintenance policy currently used by the organization, and a plan for the implantation of the alternative given for the model is produced. [ABSTRACT FROM AUTHOR]

Efficient and well-timed investment in distributed generation (DG) in distribution networks in the electricity market environment presents a big challenge for distribution companies. In this study, a real option valuation framework is proposed to determine the optimal investment strategies for DG including the investment location, size, and timing. Within the proposed framework, the profit from investing in DG is modelled, where the benefits include the operation cost savings and capacity update deferral benefit compared with a no-DG-investment scenario over the study period. Future power demands and electricity prices are modelled as stochastic variables. The candidate DG investment plans are considered as multiple mutually exclusive options, and the corresponding managerial flexibility for seizing opportunities and mitigating risk of loss upon an unfavourable unfolding of future uncertainties is assessed with real option analysis using the extended least square Monte Carlo method. The distribution of future investment strategies and optimal initial investment threshold levels under various scenarios are analysed in a case study to demonstrate the characteristics of the proposed framework and methodology. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to determine the economic power factor at the point of pov/er transfer between transmission and distribution (T & D) system for a vertically integrated utility company. An integrated reactive power management strategy is developed to optimize the planting up of reactive power compensation devices in the transmission and distribution system. The transmission and distribution network is modelled and simulated using commercially available software to analyse the transmission network losses, capacity released and voltage stability due to capacitor plant up. Economic analysis on the total cost of ownership of capacitor banks is used to determine the economic benefits of technical losses reduction and capacity, released in transmission and distribution equipment through the planting up of capacitor bank. The proposed methodology can be used by a vertically integrated power utility where a single utility own both the transmission and distribution system. A software base data analytic, power system automation and economic analysis tool was developed to facilitate the planning engineer in reactive power planning and management. [ABSTRACT FROM AUTHOR]

Recently, microgrids are attracting increasing research interest as promising technologies to integrate renewable energy resources into the distribution system. Although many works have been done on droop control applied to microgrids, they mainly focus on achieving proportional power sharing based on the power rating of the power converters. With various primary source for the distributed generator (DG), factors that are closely related to the operation cost, such as fuel cost of the generators and losses should be taken into account in order to improve the efficiency of the whole system. In this paper, a multiagent-based distributed method is proposed to minimize the operation cost in AC microgrids. In the microgrid, each DG is acting as an agent which regulates the power individually using a novel power regulation method based on frequency scheduling. An optimal power command is obtained through carefully designed consensus algorithm by using sparse communication links only among neighbouring agents. Experimental results for different cases verified that the proposed control strategy can effectively reduce the operation cost. [ABSTRACT FROM AUTHOR]

Heating energy and electricity represent a significant proportion of the overall financial expenditures over the life cycle of buildings and play a decisive role in the assessment of ecological quality. To ensure ecological and economical sustainability, the planning and construction of energy efficient buildings have become increasingly important. The present study introduces statistical models for the estimation of energy costs during the planning process as well as for the purpose of monitoring and controlling costs during operation including a wide range of facility types. Based on a data sample of 206 occupied facilities located in Germany, regression models are presented in detail including significant predictor variables. The provision of correctly specified models as well as a consistent and unbiased estimation beyond the employed data is verified by validation tests. The practical significance of the determined variables is presented by the calculation of various scenarios. The best estimation accuracy is indicated for regression models with transformed response and predictor variables achieving mean absolute percentage errors of 20.5% (heating energy) and 20.7% (electricity), respectively. An extension of the data sample, a consideration of further facility types, and an implementation of additional statistical methods may be considered by future approaches to improve the estimation accuracy. [ABSTRACT FROM AUTHOR]

A novel predictive generator out-of-step protection and transient stability monitoring scheme is presented. It is based on real-time dynamic monitoring of the system, enabled by a distributed dynamic state estimator (DSE). DSE utilizes local synchronized and nonsynchronized measurements and provides the evolution of the system's dynamic state at rates of 60 times/s. The real-time dynamic model is then utilized to evaluate the system's energy function based on Lyapunov's direct method, estimate the stability barrier, and characterize its stability. The two major components of the scheme are: 1) the calculation of the system's center of oscillations and 2) the derivation in real time of an equivalent, reduced size model used for the calculation of the generator stability barrier and its stability characterization. It is shown that the major advantage of the proposed scheme, compared with legacy generator impedance relay-based out-of-step protection, is that the out-of-step condition is predicted before its occurrence and the generator can be tripped much faster than the traditional scheme. The theoretical background of the scheme and application on an actual system are presented. The proposed scheme characterizes very accurate potential generator instability and predicts generator loss of synchronism before its occurrence, before the generator slips a pole. [ABSTRACT FROM PUBLISHER]

We introduce a MOO (multi-objective optimization) framework for the integration of renewable DG (distributed generation) into electric power networks. The framework searches for the optimal size and location of different DG technologies, taking into account uncertainties related to primary renewable resources availability, components failures, power demands and bulk-power supply. A non-sequential MCS-OPF (Monte Carlo simulation and optimal power flow) computational model is developed to emulate the network operation by generating random scenarios from the diverse sources of uncertainty, and assess the system performance in terms of CG (global cost). To measure uncertainty in the system performance, we introduce the DCVaR (conditional value-at-risk deviation) which, due to its axiomatic relation to the CVaR (conditional value-at-risk), allows the conjoint control of risk. A MOO strategy can, then, be adopted for the concurrent minimization of the ECG (expected global cost) and the associated deviation DCVaR ( CG ). In our work this is operatively implemented by a heuristic search engine based on differential evolution (MOO-DE). An example of application of the proposed framework is given with regards to the IEEE 30 bus test system, where in DCVaR is shown capable of enabling and controlling tradeoffs between optimal expected economic performance, uncertainty and risk. [ABSTRACT FROM AUTHOR]

We analyze the welfare effects of two different renewable support schemes designed to achieve a given target for the share of fluctuating renewable electricity generation: a feed-in premium (FiP), which can induce negative wholesale prices, and a capacity premium (CP), which does not. For doing so we use a stylized economic model that differentiates between real-time and flat-rate pricing and is loosely calibrated on German market data. Counter-intuitively, we find that distortions through induced negative prices do not reduce the net consumer surplus of the FiP relative to the CP. Rather, the FiP performs better under all assumptions considered. The reason is that increased use of renewables under the FiP, particularly in periods of negative prices, leads to a reduction of required renewable capacity and respective costs. This effect dominates larger deadweight losses of consumer surplus generated by the FiP compared to the CP. Furthermore, surplus gains experienced by consumers who switch from flat-rate to real-time pricing are markedly higher under the FiP, which might be interpreted as greater incentives to enable such switching. While our findings are primarily of theoretical nature and the full range of implications of negative prices needs to be carefully considered, we hope that our analysis makes policy-makers more considerate of their potential benefits. [ABSTRACT FROM AUTHOR]

An investigation of the link between electricity theft and power disruptions simultaneously provides a rare and contemporary cross-country assessment of electricity theft. The findings suggest that electricity theft in Haiti ranked first overall, and that extensive power theft has risen internationally since 1980. The direct cost of electricity disruptions ranged from US$0.43 to US$9.91 per kWh. [ABSTRACT FROM AUTHOR]

The next years should bring about a rapid transformation of the electricity sector towards high levels of renewable generation and increasing numbers of electric vehicles. Smart grids are seen as the silver bullet responding to the challenge of integrating renewables, managing flexibility, and keeping the costs down in distribution networks. Network unbundling on the other hand is essential for competition in the liberalized electricity industry. It forces independence of the networks and thereby eliminates concern that incumbent integrated (network) firms discriminate against new entrants. With smart grids the unbundling questions become relevant for distribution networks, because active control in smart grids entails discrimination potentials. However, smart grids exhibit coordination needs for efficient system operation and unbundling eliminates firm-internal coordination. Accounting for both aspects, this paper proposes an independent system operator to govern smart distribution grids. It eliminates discrimination incentives and serves coordination needs, thereby striking a balance between both competition and efficiency goals. [ABSTRACT FROM AUTHOR]

Copyright of Technical Transactions / Czasopismo Techniczne is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, the electricity cost minimization problem is considered for a residential microgrid which consists of multiple households (users) equipped with renewable-based distributed energy resource (DER). Each user has a set of nonshiftable and shiftable loads. Bidirectional electricity transactions are allowed, and a dynamic pricing model for the purchasing/selling of electricity from/to the grid is proposed. In order to reduce the electricity cost, the following decisions needed to be made: 1) scheduling decisions for the shiftable loads; 2) purchasing/selling decisions for each user at each time slot; and 3) amount decisions of the electricity purchased/sold by the users. An optimization problem to minimize the total electricity cost is formulated to obtain the optimal amount of electricity consumed, sold, and purchased for each user, respectively. A centralized algorithm based on dynamic programming, $Q$-learning, and Lyapunov methods are proposed to solve the optimization problem with perfect information, with partial information, and without information of any time-varying parameters, respectively. For the latter two cases, distributed algorithms are designed for practical implementation. Simulation results show that the proposed schemes can provide effective management for household electricity usage and bidirectional transactions. [ABSTRACT FROM PUBLISHER]

This paper presents an effective method of network overload management in power systems. The three competing objectives 1) generation cost 2) transmission line overload and 3) real power loss are optimized to provide pareto-optimal solutions. A fuzzy ranking based non-dominated sorting genetic algorithm-II (NSGA-II) is used to solve this complex nonlinear optimization problem. The minimization of competing objectives is done by generation rescheduling. Fuzzy ranking method is employed to extract the best compromise solution out of the available non-dominated solutions depending upon its highest rank. N-1 contingency analysis is carried out to identify the most severe lines and those lines are selected for outage. The effectiveness of the proposed approach is demonstrated for different contingency cases in IEEE 30 and IEEE 118 bus systems with smooth cost functions and their results are compared with other single objective evolutionary algorithms like Particle swarm optimization (PSO) and Differential evolution (DE). Simulation results show the effectiveness of the proposed approach to generate well distributed pareto-optimal non-dominated solutions of multi-objective problem [ABSTRACT FROM AUTHOR]

The purpose of this paper is to measure the environmental costs of overhead power transmission lines (PTLs) in Korea by using a choice experiment (CE) approach. To this end, a mixed logit model is employed to explicitly incorporate preference heterogeneity and avoid the assumption of independence from irrelevant alternatives that is required in conditional logit models. For selecting a preferred alternative, we consider the trade-offs between price and the attributes of environmental impacts from overhead PTLs such as visual disamenity, land use and electric and magnetic fields (EMFs). The results reveal that unlike visual disamenity and land use, EMFs are not statistically significant. This can be interpreted as implying that many respondents are more interested in land use related to property rights than EMFs. This study provides useful information to policy makers for the development and implementation of more appropriate policies to deal with the environmental damage that is caused by overhead PTLs. Undergrounding PTLs without considering the construction cost can lead to an increase in electricity rates. Therefore, we may take into account a cost-effective option in future policies for social optimality. [ABSTRACT FROM PUBLISHER]

El artículo analiza diversas resoluciones y sentencias en el área de Derecho de Energía de España emitidas entre diciembre de 2013 y marzo de 2014. Los temas discutidos incluyen la resolución sobre tarifas de gas natural, diversas resoluciones sobre el precio y la producción de energía eléctrica y resoluciones de la Comisión Nacional de los Mercados y la Competencia con respecto la industria eléctrica de España.

HVDC power transmission is now being considered not only for point-to-point interties, but also as true grids where several operators may tie into the grid, each having its own economic sphere. In this new situation, it is important that transmitted energy be distinguished from losses incurred in the converter stations, to enable a fair distribution of costs for grid operation. To this end, a metrology infrastructure is needed where high-current and high-voltage transducers must be possible to calibrate traceably, and where dc electricity meters can be calibrated and approved. A research project is currently working with these questions in a concerted European research effort, funded by the European Commission. The present publication highlights important aspects of this work. [ABSTRACT FROM PUBLISHER]

To solve the problem of secondary distribution systems planning, this paper proposes a methodology using a tabu search algorithm as a solution technique. The problem is formulated as a nonlinear mixed-integer model, which takes into account the location and capacity of new elements (distribution transformers and primary-secondary distribution networks), relocation of existing distribution transformers, increasing the capacity of existing elements, secondary network reconfiguration, and phase balance. It also considers the costs associated with connections between primary and secondary networks and energy losses in distribution transformers. The methodology is applied to two test cases: in the first, a comparative analysis with the Chu-Beasley genetic algorithm is made to verify the efficiency of the proposed methodology; and in the second, the results are analyzed in a Colombian distribution system. In both cases, the results are of high quality, supporting the proposed methodology. [ABSTRACT FROM AUTHOR]

Performance-based regulations accompanied by quality regulations are gaining ground in the electricity distribution business. Several European countries apply quality regulations with reward and penalty schemes (RPSs), where the distribution system operator (DSO) is rewarded (or penalized) when fulfilling (or not fulfilling) an adequate level of reliability to its customers. This paper develops a method that the regulator can use before enforcing a regulation to get an understanding of the impact different RPS design solutions have on the DSO's financial risk and incentives to invest in reliability. The proposed method also includes a sensitivity analysis to identify which are the most important parameters in an RPS. The new method is applied to three regulatory challenges to evaluate their RPS design solutions. Results show that the choice of scheme design and cost model used to decide the incentive rate have a large impact on the DSO's financial risk and incentive to invest. [ABSTRACT FROM PUBLISHER]

Stability and cost optimality of power generation and supply systems must not be considered independently from one another. Simple examples show that optimizing cost without considering stability may result in modes of operation that, while economically optimal, are unstable. We demonstrate that stability, robustness, and optimality can be considered systematically and simultaneously by combining bifurcation theory and nonlinear optimization. Essentially, the proposed method enforces a backoff distance between the optimal point of operation and operational or stability boundaries in the space of the optimization variables, where bifurcation theory is used to describe nonlinear stability boundaries. [ABSTRACT FROM PUBLISHER]

Copyright of Research Papers of the Wroclaw University of Economics / Prace Naukowe Uniwersytetu Ekonomicznego we Wroclawiu is the property of Uniwersytet Ekonomiczny we Wroclawiu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Econometrics / Ekonometria is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El artículo presenta una lista de decretos en materia de energía emitidos en España entre abril y julio de 2012, así como sentencias que sientan jurisprudencia sobre este sector. Algunas regulaciones discutidas son parámetros para el transporte de gas, normativa sobre tarifas de distribución de electricidad y responsabilidad del Ministerio de Industria, Energía y Turismo de fijar los peajes de acceso a las redes de energía eléctrica.

The inconveniences of the reactive power are presented and from this are carried out the mathematical models of its economic effects applicable to secondary power systems. The effects taken into account are: the costs of the capacitors banks, the expenses of paying-off to the banks, the expenses of power losses to the banks, the benefits for the improvement of the power factor, included the reduction of power loss in the system, as well as the benefits for the liberation of the load capacity, to the case of companies where the latest aspect can represent an economic attractiveness. For the analysis after and before compensation, are consider load flow algorithm witch load model adjust. According to electrical tariff structures in Cuba, these effects are integrated in a function of economic analysis, for this case the net actual value, which serves as base for the position of the optimization problem, which can derive in the correct selection of the devices compensators. [ABSTRACT FROM AUTHOR]

The article focuses on a study which examined long-run electricity transmission cost functions based on a definition of transmission output in terms of point-to-point transmissions or financial transmission right (FTR) obligation. A model that combines merchant and regulatory approaches was adopted in this study. Information on the difference between an FTR and a physical right is provided. Results of the study showed that a reduction in power flow leads to negative marginal cost range.

Over the past few years, the Midwest Independent Transmission System Operator, Inc. (MISO) has transformed the electric utility industry in 13 Midwestern US states through the development and implementation of energy and ancillary services markets. MISO uses mixed-integer programming to determine when each power plant should be on or off. Operations research methods set energy output levels and establish the prices at which energy trades. These new markets increased the efficiency of the existing electric infrastructure (power plants and transmission lines) in the Midwest, improved the reliability of the grid, and reduced the need for future infrastructure investments. These advances enabled the MISO region to realize between $2.1 billion and $3.0 billion in cumulative savings from 2007 through 2010. We expect additional savings of $6.1 billion to $8.1 billion through 2020. [ABSTRACT FROM AUTHOR]

This paper describes and tries to quantify the effects of some factors that have affected costs of state owned electric utilities in Mexico (energy losses, fuel and labor). It is noted that the impact of the increase in fuel prices on the electric utilities' total cost in the last years has been important. However, the "over-cost" associated to energy losses and labor is also significant and comparable to the impact of the increase in fuel prices. The structure of cross subsidies in the industry is also described, pointing out that it is complex and makes the performance evaluation of the state owned electric utilities difficult. [ABSTRACT FROM AUTHOR]

Phase shifting transformers (PSTs) can be regulated to minimize total generation cost in optimal power flow problems. Under the perception that there exists multiple optimal solutions of PST angle adjustment and better economy may be achieved by controlling a small fraction of PSTs, this letter proposes a mixed integer linear programing model to optimally determine the subset of PSTs for angle adjustment. Numerical results on several test systems including large-scale systems show that the proposed model can provide better economic dispatch with regulating a small number of PSTs. [ABSTRACT FROM AUTHOR]