Power Distribution Utilities Research Articles

Condition monitoring of 11 kV distribution system insulators incorporating complex imagery using combined DOST-SVM approach

The increasing demand for the uninterrupted supply of power is equally increasing the necessity to monitor the health of the distribution network. The failure of the network implicates loss of supply and hence incurs huge loss to power distribution utilities. This paper envisages an algorithm to monitor the condition of overhead distribution line insulators with complex background, keeping in view pragmatic considerations. Complex background necessitates an arduous effort to monitor the condition of insulators and requires a powerful technique to monitor and identify the condition of the insulator. Support vector machines (SVM) and Adaptive neuro-fuzzy inference system (ANFIS) are used to estimate the condition of the insulator with the aid of features extracted from Discrete Orthogonal STransform (DOST). The algorithm is developed in MATLAB environment using the image processing toolbox. Superiority of the SVM over ANFIS has been shown from the results for complex background to validate the efficacy of proposed technique.

A Dynamic Programming Algorithm for Optimal Design of Tidal Power Plants

A dynamic programming algorithm is proposed and demonstrated on a test case to determine the optimum operating schedule of a barrage tidal power plant to maximize the energy generation over a tidal cycle. Since consecutive sets of high and low tides can be predicted accurately for any tidal power plant site, this algorithm can be used to calculate the annual energy generation for different technical configurations of the plant. Thus an optimal choice of a tidal power plant design can be made from amongst different design configurations yielding the least cost of energy generation. Since this algorithm determines the optimal time of operation of sluice gate opening and turbine gates opening to maximize energy generation over a tidal cycle, it can also be used to obtain the annual schedule of operation of a tidal power plant and the minute-to-minute energy generation, for dissemination amongst power distribution utilities.

Defining a quality index for electric power utilities using multiple criteria decision support and time series analysis

This paper presents a hybrid multi-criteria method developed through the combination of the Analytical Hierarchy Process (AHP) and exponential smoothing techniques applied in time series forecasting. To illustrate its use, a model was developed with the aim of creating a quality index for electric power distribution utilities. The conclusions highlight the need to take into account the results obtained in the latest months for those utilities, but giving less attention to those obtained in the earlier months. This characteristic of the problem led to the idea of incorporating the mathematical formulation of the exponential smoothing into the aggregation function of the AHP. At the end, the utility company is given a score between 0 (zero) and 10 (ten).

A residential consumer payment capability index based on fuzzy logic inference

The non-payment rate has been one of the main problems faced by the electric power distribution utilities. It is therefore essential that the utilities provide a methodology to assess the capability of a residential consumer to pay on time his/her electricity bill. As such, the utility will be able to simulate strategies and mitigate the risk of non-payment. This article presents a proposal based on fuzzy logic approach to compute a “Payment Capability Index” PCI for residential customers. A spatial view of PCI is provided by illustrative maps obtained by Geographic Information System GIS.

Hierarchical multiple criteria optimization of maintenance activities on power distribution networks

Power distribution utilities must transport quality and reliable electric energy to all of the customers in a given network within specified targets. Failure of one of the network components is the main factor that compromises a system’s reliability. Maintenance actions, such as repairs and component replacements, are employed to avoid power interruptions or to resume the healthy network operation. This paper reports the relationship between maintenance activities and reliability as an optimization problem with two criteria: cost of maintenance activities and the maximum value for a system average interruption frequency index planning period. Solving these problems for each network provides local efficient solutions and associated trade-off curves. These solutions are optimally combined to solve a global-level multiple criteria optimization problem, revealing the local efficient solutions and associated trade-off curves for a group of networks or for a whole company. The procedure solves the hierarchical multiple criteria maintenance resources allocation problem and provides information to assess the decisions on maintenance activities at all decision levels in the network management. This procedure is applied to one illustrative example and real-life case studies to demonstrate its benefits.

DMS - basis for increasing of green distributed generation penetration in distribution networks

Modern (electric power) distribution utilities are faced with high penetration of distributed (electric) generation. Renewable generation is of prime interest. Within this generation, the green one incorporating solar (photovoltaic) and wind generation is the most important. Consequently, the following two imperatives are established in modern distribution utilities: 1) absorption of as much of available (connected to network) green generation as possible and 2) increasing of the limit of green distributed generation penetration. This generation is a significant basis of Smart Distribution Grid Concept. Distributed generation transfers passive distribution network into active one. The active distribution network analysis, control, operation management and planning become significantly complex. This complexity radically hinders the achievement of two above stated imperatives referring to the distributed generation penetration. This paper proves that Distribution Management System is a unique powerful system that integrates all tools necessary for surpassing main difficulties in the achievement of the both imperatives. The proof is obtained by the elaboration of a set of power applications (mathematical calculations) integrated in the Distribution Management System. The most important power applications, which deal with voltage / reactive power control, are specially stressed.

Improving SVM-Based Nontechnical Loss Detection in Power Utility Using the Fuzzy Inference System

This letter extends previous research work in modeling a nontechnical loss (NTL) framework for the detection of fraud and electricity theft in power distribution utilities. Previous work was carried out by using a support vector machine (SVM)-based NTL detection framework resulting in a detection hitrate of 60%. This letter presents the inclusion of human knowledge and expertise into the SVM-based fraud detection model (FDM) with the introduction of a fuzzy inference system (FIS), in the form of fuzzy IF-THEN rules. The FIS acts as a postprocessing scheme for short-listing customer suspects with higher probabilities of fraud activities. With the implementation of this improved SVM-FIS computational intelligence FDM, Tenaga Nasional Berhad Distribution's detection hitrate has increased from 60% to 72%, thus proving to be cost effective.

Optimal Location and Sizing of Distributed Generation In a Power Distribution System

Modern electric power distribution utilities are continuously underpressure for expansion of their networks in order to face the load growthand to properly supply their consumers. To meet these objectives, thereis a need to provide acceptable climate for the entry of distributedresources and innovative operating practices. This article focuses ondetermining the effect of inserting a Distributed Generation (DG) unitin a power distribution system in India. The effect on the system volt-age profile and line losses is evaluated. This has been accomplished bymodeling the connection of a DG unit to different distribution buses andvarying the DG unit size in a 13-bus test feeder. A financial evaluationhas been carried out to examine implementation viability. The resultsshow that the voltage profile is improved, losses are reduced and conse-quently the utility can obtain financial benefits when DG is incorporatedinto the system.

Optimal Location and Sizing of Distributed Generation In a Power Distribution System

ABSTRACT Modern electric power distribution utilities are continuously under pressure for expansion of their networks in order to face the load growth and to properly supply their consumers. To meet these objectives, there is a need to provide acceptable climate for the entry of distributed resources and innovative operating practices. This article focuses on determining the effect of inserting a Distributed Generation (DG) unit in a power distribution system in India. The effect on the system voltage profile and line losses is evaluated. This has been accomplished by modeling the connection of a DG unit to different distribution buses and varying the DG unit size in a 13-bus test feeder. A financial evaluation has been carried out to examine implementation viability. The results show that the voltage profile is improved, losses are reduced and consequently the utility can obtain financial benefits when DG is incorporated into the system.

Análise dos Normativos de Contabilidade Internacional sobre contabilização de contratos de parcerias público-privada

This article deals with, in the context of the accounting convergence to international standards for publicly held companies to international standards, due to Law n°11.638/07, accounting for the concession arrangements contracts for public-private partnerships (PPP) by the operator when the objective is to perform the contract and/or operate infrastructure (roads, power distribution, water and other utilities). Such contracts generate various accounting tasks, with different economic characteristics, which give explanations and interpretations in the light of specific economic and accounting theories. It is performed with emphasis a literature review on PPP contract risks, specific accounting standards and discussion of disclosure of contracts risks. We conclude that although the standard has the objective to deal with the conflicts arising from economic events of the PPP, adjustments should be done due to lack of risk measurements on the standard.

An application of predictive reliability analysis techniques in Brazil’s northeast distribution networks

Presently, electric utilities are facing an increasing number of complaints about distribution system reliability. This fact has been caused by the growth of sensitive loads in all the customer sectors. Due to this, power distribution utilities are applying predictive reliability assessment (PRA) in the distribution system planning to achieve the customers reliability requirements. This paper has its objective as the description of the application of the PRA technique in a feeder of a distribution utility located in the Northeast of Brazil. The results obtained with the proposed PRA model allowed the identification and diagnosis of critical areas and vulnerabilities in the distribution feeders.

Performance and efficiency in Colombia's power distribution system: Effects of the 1994 reform

We assess evolution in performance, efficiency and productivity of Colombia's power distribution utilities before and after the 1994 regulatory reform that introduced electricity market activities for the power sector in 12 distribution companies from 1985 to 2001. Performance is evaluated contrasting changes in mean and median by Wilcoxon Rank Sum and Pearson tests on financial and other performance indicators. Technical efficiency is measured by means of Data Envelopment Analysis (DEA). The nature of the dataset allows the estimation of Malmquist productivity index and its evolution in time. Results show a recovery after the reform in the main performance indicators of profitability, partial input productivity, and output. Plant efficiency and productivity increased after the reform, mainly in the largest utilities used as benchmarks in the DEA efficiency scores measures. Meanwhile, the less efficient power distribution companies did not improved after the reform and were not able to undertake plant restructuring to catch-up in plant efficiency with respect to the Pareto efficient input allocations. Econometric results on DEA efficiency scores suggest a positive effect of policy reform.

Solar radiation in the Brazilian Northeast

The significant increase in recent years of the number of rural electrification systems (some thousands of them do exist) using photovoltaic technology installed in the Northeast of Brazil (1,500,000 km 2, approximately 42 million people) used for illumination or water pumping, calls for an improvement on the design procedures in order to reduce the burden of capital costs per unit of generated power. Such objective can be accomplished as long as a better knowledge about the solar resource is achieved, considering how much these applications depend on it. The sources of information on solar radiation in Brazil are quite varied at both institutional and publication level. At institutional level, among others, we can find the National Institute of Meteorology (INMET), State Departments of Agriculture, research institutes, universities and electric power generation and distribution utilities. Progress reports or scientific and technical journals are the main publishing vehicles where this information can be found. This way, data quality varies considerably, showing spatial and temporal discontinuities, in addition to the fact that measurement instruments and physical units of registered data are not standardized. The Solarimetric Atlas of Brazil was recently published [Brazilian Solarimetric Atlas, Final Technical Report I–IV (1997); Renewable Energy 18 (1998) 393] contains that information, which is grouped, evaluated, qualified, and presented in a standardized way. It is one of the best currently existing sources of information, and it certainly consists of almost the entirety of the existing information on the solar resource (data on solar radiation and sunshine hours) in Brazil. By using this database, simultaneous records of solar radiation (measured with pyranographs or pyranometers) and sunshine hours with heliographs were obtained in 35 different places in the Northeast region. Coefficients a and b were calculated for those different places using Angstrom's correlation. Using the geostatistical interpolation method known as ‘kriging’, the values of a and b were placed on contour maps, the coverage of which is the Northeast region. The relevant kriging estimate error maps were also obtained. The general objective of this paper is to improve the amount of the currently existing information on the solar radiation in the Northeast of Brazil. Regarding this, the contour maps of coefficients a and b have made possible estimating solar radiation in 82 additional locations, were only sunshine hours data were available.

La controversia entre la Comisión de Tarifas Eléctricas y las empresas de distribución de energía eléctrica de Lima Metropolitana: Un enfoque de teoría de juegos

In September 1997, CTE set a new distribution rate after estimating the investment value, called New Replacement Value (VNR) for power distribution utilities in Peru. This estimation is an indispensable tool to set rates for 1997-2001 but raised a controversy between CTE and the regulated companies that reached the judiciary and generated a series of contradictory opinions on rate setting, regulation methods and LCE opinions. A theoretical model of game theory show that if the agents acting maximizing profits, the Nash equilibrium will be appropriate by the LCE. Although, if there are exist a deviation by populist causes the equilibrium will be inefficient for the user but harmful for the company. In the next period, the companies will have incentives for underinvestment or recoil of the business but will never invest efficiently. We concluded that the important question is not if the regulatory entity is independent or not. The most important is that the government provides a believable commitment, as much to consumers as to investors for the development of the sector.