Voltage Sags and Interruptions

Publicación a texto completo no autorizada por el autorLos equivalentes eléctricos para análisis de transitorios electromagnéticos convencionalmente se representan como un simple circuito equivalente basado en estudios de cortocircuito a frecuencia de la red, sin embargo ésta representación no es adecuada para estudios de transitorios electromagnéticos debido a la presencia de otras componentes de frecuencia que se presentan en eventos como: energización de líneas de transmisión, bancos de capacitores, reactores y transformadores, sobretensiones debido a descargas atmosféricas, recierres en líneas de transmisión, etc. La ocurrencia de estos eventos produce distorsión de las ondas de tensión y corriente, teniendo componentes de frecuencia desde las decenas de Hz hasta las decenas de kHz, por lo que se necesita un equivalente eléctrico que considere la respuesta del sistema en un cierto rango de frecuencias. En esta tesis se propone una metodología para obtener un equivalente que cons...

Electricity is essential for the economic and social development of communities. The national government in each territory regulates electricity because is a public service. Utilities manage the electricity supply to meet the communities' demand while considering economic and financial feasibility. Regulation's purpose is to ensure efficient, secure, and reliable operation within the sector, maintaining quality and safety. This paper contains an analysis of the management criteria for the quality of the electrical energy service and the indicators in the Caribbean region of Colombia.

This article presents a procedure for the integral assessment of electrical power quality in industrial electrical systems. The research is crucial due to rising challenges in power quality arising from increased nonlinear electrical loads in industrial processes. The procedure is structured into sequential steps that consider diagnosis, causes, effects, and solutions to electromagnetic phenomena affecting electrical power quality. The integral approach and its path to continuous improvement significantly distinguish it from existing scientific literature approaches. This procedure serves as a complement to the objectives of national and international standards for electrical power quality.

Generally distributed generation (DG) is connected at distribution level voltage and it provides support to the distribution network. The connection of DG with distribution system improves the system reliability. The reliability improvement depends on the capacity and availability of DG and on the location of the DG connected to the distribution system. The aim of the paper is to study the impact of different locations of DG on reliability of distribution system.

In this paper, voltage sag compensation of point of common coupling (PCC) using a new structure of fault current limiter (FCL) is proposed. The proposed structure prevents voltage sag and phase angle jump of substation PCC after fault occurrence. This structure has a simple control method. Using semiconductor switch (IGBT or GTO) at dc current rout leads to fast operation of the proposed FCL and consequently, dc reactor value is reduced. On the other hand, the proposed structure reduces total harmonic distortion (THD) on load voltage and it has low ac losses in the normal operation. As a result, other feeders which are connected to the substation PCC will have good power quality. Analytical analysis, simulation results using PSCAD/EMTDC software and experimental results are presented to validate effectiveness of this structure. Index Terms─Voltage sag, fault current limiter, power quality, point of common coupling (PCC), semiconductor switch, THD.

The demand for electricity is increasing at a very high rate and demand for power is running ahead of supply. Introduction of Distributed energy resources (DES) is the biggest change happening to the distribution network. There is an increased integration of DES with the distribution network using power electronics converters as to meet the continuously increasing demand of electricity. In future it is expected that the penetration level of distributed energy resources will further increase. The connection of distributed energy resources with the distribution network result in increase in the value of fault current which can causes the abnormal conditions in the entire power system network . The equipment installed at generating station and at substation is very expensive. Therefore it is necessary to protect these equipment from fault current. A Fault Current Limiter (FCL) is a revolutionary power system device that overcomes the problems due to increased fault current levels. It i...

Reliability analysis is the evaluation of customer supply interruption probability for a given network configuration. Reliability analysis simulates and examines systematically all single and multiple failures, for every failure, the unsupplied loads, the interruption durations and the possibilities of power restoration are determined. A Power system is set up basically to meet the demands of the customers. However, interruptions which are largely unavoidable contribute to the unavailability of power and thus prevent power system from achieving this. In most cases, it is the sustained interruptions that greatly affect both the utility company and its customers. The need for stable electricity supply in Nigeria cannot be overemphasized as it is a prerequisite to economic, social and technical development. The consequence of interruption of supply in the transmission system is considerably high because an outage event in the transmission system can propagate and paralyze a widespread geographical area. The collected data were analyzed mathematically to estimate the reliability of the substation and the customer reliability indices computed for a twelve-month period. It was observed that the substation was available for an average 61.45% which is very low compared to IEEE standard. Thus, the overall system availability shows that the system performance is poor. I.

This paper presents a methodology in order to evaluate the security of electrical industrial systems considering security, quality, reliability and availability factors and the system response to sudden disturbances such as short circuit and harmonics. The models proposed using the probabilistic networks theory: Bayesian Networks and Generalized Stochastic Petri Nets. The obtained results allow the identification of hidden failures and erroneus coordination of protection. The models are tested on the IEEE 493 system proposed by the IEEE Gold Book.

In this thesis, a methodology for the optimal allocation of reclosers in distribution feeders was developed combining the techniques of Chu-Beasley genetic algorithm, for the search of optimal allocation, and Monte Carlo simulation for the reliability assessment. The objective function to be minimized is the non served energy, for what a detailed modeling of the load composition by residential commercial and industrial customers was developed. This methodology seeks the optimal allocation for a number of reclosers given by the analyst because: i. A global solution for the number of reclosers would require huge computational resources, i. e. computer memory capacity and computational time. ii. Due to the limited resources of many utilities, although an optimal number of reclosers is known, there is no the resources neither the capacity to go into loans to buy all them but for some of them. iii. The methodology has to be useful for the case that some reclosers are available to be inst...

This paper investigates the frequent power cut on the 11kV feeders of Ugbowo 2x15MVA, 33/11kV electric power distribution network. Annual data of daily power outages from August 2019 to July 2020 of the 11kV feeders were collated and collected from the Ugbowo distribution network. The daily outages of the 11kV feeders were used to compute the monthly and the yearly reliability indices of the feeders of the Ugbowo distribution network. Both the monthly and annual failure rates, MTTR, MTTF, MTBF, availability and unavailability were computed and analyzed using the Load Point Indices (LPI) and the Microsoft Excel was used for graphical interpretation in order to estimate the reliability indices and to determine the frequency of power outages of the network. Also, the Performance Indices (PI) of the system were evaluated for an in-depth assessment. The annual and monthly failure rates, mean time to repair, mean time to failure, mean time between failure, system average interruption frequency indices (SAIFI), system average interruption duration indices (SAIDI), average service availability index (ASAI), etc for a period of twelve (12) months were analyzed. The computed results obtained from the analyses of the 11kV feeders of the distribution network showed that the power unavailability is very high for the period under study with Ugbowo 11kV feeder having the highest power unavailability of 76.52%, Eguaedaiken 11kV feeder 73.42%, FGGC 11kV feeder 69.50% and Uselu 11kV feeder 66.96% in the network. The annual failure rate results revealed that Ugbowo 11kV feeder has the highest failure rate of 46.52%, followed by Eguaedaiken feeder 44.83%, FGGC feeder 44.27% and Uselu feeder 41.60%. This is due to frequent power outages resulting from regimented load shedding (scheduled outages) being practice in the network as way to manage equipment limitations, poor energy management system, etc. and unscheduled (forced) outages due to faults in the network. Furthermore, the PI of the system revealed that the annual total outage duration (SAIDI), outage frequency (SAIFI) and percentage availability (ASAI) were 175.7504hours, 3.3780f/cu.yr and 97.99% which is a far cry from the international acceptable standard value (IASV) of 2.5 hours, 0.01 and 99.99% respectively which showed that the power supply services in the network is unreliable.

With respect to power distribution networks, which includes two types of air and ground networks; it is worth noting that the use of the air networks is more economical and therefore dominates the existing air networks. In this paper, the authors have worked on the reliability indexes changes for a month period. As well, the paper's aim is to make a strategy in short-term (monthly) to network management in order to alleviate cutoff number and time, ENS, increasing customer satisfaction from electric distribution companies and comparing the performance of air and ground networks. The paper was done based on a case study sample substation of a network in Bakhtar regional electric company, Iran. Also, simulation results have obtained by CYME PSAF.

Voltage events are one of the most common and harmful disturbances of power electric systems. Voltage dips, swells and interruptions are included under this heading. Given the economic cost that these disturbances represent for electrical power transmission and distribution companies and the industry, it becomes imperative to detect and classify them properly. Several classification criteria and algorithms have been proposed in the literature as analysis tools to differentiate voltage events by their characteristics and, if possible, to determine their causes and consequences. Even though some of these approaches make a correct classification of the voltage events, there are certain operation conditions that are common in real electrical grids, in which the classification criteria, and their corresponding algorithms, make a wrong classification. These particular conditions, together with the lack of a fair comparison in a common scenario, have not been addressed in the specific field literature. This work explores in detail all these aspects by evaluating the symmetrical components criterion and ABC classification criterion, and rigorously analyzes three specific algorithms: the Symmetrical Components Algorithm, the Six Phases Algorithm and the Space Vector Algorithm. Drawbacks arise from both classification criteria and algorithms. The causes of the classification errors are described and discussed in detail in order to better understand the problem, and evidence the constraints of these classification methods.

This paper presents the reliability improvement with effect of customer scattering on distribution system with Distributed Generation (DG). The test system is studied in six different cases based on different customer scattering patterns. Each customer scattering case is analyzed for finding the reliability indices of the distribution system without DG, and with installation of DG at various locations along the feeder. In addition, the algorithm for assessment of average restoration time of load point is presented when DG is installed. The proposed algorithm is tested on a simple system consists of nine load points. The reliability improvement is measured by reliability indices that include SAIFI, SAIDI, CAIDI, ENS and AENS. On the other hand it provides some useful conclusions such as the customer scattering and restoration time effect the optimal location of DG in terms of system reliability.

This paper presents the reliability improvement with effect of customer scattering on distribution system with Distributed Generation (DG). The test system is studied in six different cases based on different customer scattering patterns. Each customer scattering case is analyzed for finding the reliability indices of the distribution system without DG, and with installation of DG at various locations along the feeder. In addition, the algorithm for assessment of average restoration time of load point is presented when DG is installed. The proposed algorithm is tested on a simple system consists of nine load points. The reliability improvement is measured by reliability indices that include SAIFI, SAIDI, CAIDI, ENS and AENS. On the other hand it provides some useful conclusions such as the customer scattering and restoration time effect the optimal location of DG in terms of system reliability.

Today, utilities are trying to maximize system reliability, improve efficiency, and reduce costs by using protection system, distributed generation system, by reconfiguring the feeder, by connecting the end of feeder to other substation and so on. However, when it tries to use some techniques (reconfiguring the feeder, connecting the end of the feeder to another substation); the techniques have positive and negative impact on reliability improvement. The substation which is taken in this paper has the System Average Interruption Frequency Index (SAIFI) and System Average Interruption Duration Index (SAIDI) is 521.46 interruptions per customer per year and 446.82 hours per customer per year respectively. The historical outage interruption data of the years of 2016-2018 has been used as a base year. The study has evaluated the new substation to improve the system reliability. The simulation results have been done with the help of Electrical Transient Analysis Program (ETAP 12.6) software. In this paper includes improvement of the system reliability of the feeder is supplied from two substations or new substation should be connected at the end of the feeder. Due to the new substation, the length of the feeder will vary, and the variation of the feeder has significant effect on power reliability. The value of SAIFI and SAIDI after the new substation connected is 169 and 96 respectively. Since the new substation has negative impact, the value of indices is not reduced more.

Electric power delivers a predicable per condition for the technological, economic and political development of any countries and it is vital for each individual. Power outage is serious problem in Ethiopia at the whole of distribution network. This is due to most interruptions are frequently and much time service restoration, that is why most customers of Ethiopia their day to day activities highly affected and they are strongly complain to Ethiopia electric utility. But this power outage affected the cost of customer and Ethiopian utility. Power system is to provide an adequate and security electrical addressing to its demands as economically as alternative with reasonable level of reliability. Most electrical power distribution system reliability is one of the major issues for the demands. Reliability is the chance that a network or components done their assigned task for a given period of time under the working time stumbled upon during its anticipated lifetime. Most of developing country including Ethiopia electric power distribution network has received considerably less of the attention to reliability designing and evaluation than have generating and transmitting systems. Now a day life is directly or indirectly depends on electric power so that utility should deliver reliable power every day for 24 hours and each year for 8760 hours to satisfy human needs and to perform their works as much as possible with less economy.

Abstract. Electrical power system robustness is defined as the intrinsic capacity of an electrical power system to maintain assigned disturbance levels when external conditions change. In this paper the concept of robustness against is applied to the voltage dips, one of the most severe disturbances in power quality. Using graphical color schemes as immediate tools, improvements and/or degradations of the electrical power system robustness are assessed when structure modifications are implemented. The proposed tools are applied to real distribution systems. Key words Power quality, power system reliability, power transmission, power distribution, voltage dips.

The paper assesses the reliability performance of the 33kV Kaduna Electricity Distribution Feeders, Northern Region, Nigeria. The daily outages data of the feeders for the period of 16 months (January, 2011 to December, 2012) were collected and used to compute the monthly reliability indices for the feeders. Mogadishu and Rural Feeders recorded the highest failure rates in November 2011 when compared to other feeders, due to their frequent outage occurrence which brings about the highest loss of energy and monetary worth of loss to the PHCN management. The high forced outages recorded are indications of unreliable performance. Monthly reliability indices tables developed shows the Actual Energy Loss, Forced outage hour (FOH), failure rate, Mean time between failures (MTBF), Mean time to repair (MTTR), and the availability. These results were analysed, discussed, conclusions drawn and recommendations proposed to improve the reliability performance of the feeders studied.

Abstract-This paper describes the problem of voltage sags and swells and its severe impact on non linear loads or sensitive loads. The dynamic voltage restorer (DVR) has become popular as a cost effective solution for the protection of sensitive loads from voltage sags and ...

En este artículo se estudia la localización de fallas en el sistema de distribución eléctrica, basándose en el procesamiento de las señales de cortocircuito. Para este análisis se propone la simulación de casos mediante el software CYME, empleando la transformada wavelet para el estudio de la señal obtenida y descompuesta. Se propone el método del árbol mínimo en expansión para que la localización de las faltas sea
óptima y el tiempo de reconexión sea mínimo. Este análisis toma en cuenta la ubicación de los reconectadores en el sistema de distribución que servirán como almacenadores de información. En esta investigación
se desarrolló un algoritmo de localización de fallas mediante el análisis de fenómenos transitorios, lográndose buena precisión en tiempo-frecuencia. Aplicando el método propuesto se descompone la señal en diferentes niveles obteniéndose los parámetros necesarios para determinar la distancia de la falla.

En este artículo se presenta una revisión del estado del arte de la caracterización, identificación y localización de los huecos de tensión. Los métodos presentados son el producto de diferentes análisis aplicados a la perturbación electromagnética, específicamente a las formas de onda de tensión y corriente, donde basándose en la teoría de circuitos eléctricos, transitorios electromagnéticos y el conocimiento del fenómeno se proponen atributos y descriptores que permiten caracterizar las perturbaciones de acuerdo a cierta característica de interés. Se hace una revisión tanto de caracterizaciones básicas como de metodologías que integran clasificadores y descriptores más complejos. Se hace énfasis en los métodos de caracterización, junto con sus atributos y descriptores, incluyendo sus limitantes y posibles mejoras. De acuerdo al nivel de desarrollo encontrado en estos estudios, resulta la necesidad de nuevas metodologías que integren módulos de caracterización, de diagnóstico de ca...

This paper presents a methodology in order to evaluate the security of electrical industrial systems considering security, quality, reliability and availability factors and the system response to sudden disturbances such as short circuit and harmonics. The models proposed using the probabilistic networks theory: Bayesian Networks and Generalized Stochastic Petri Nets. The obtained results allow the identification of hidden failures and erroneus coordination of protection. The models are tested on the IEEE 493 system proposed by the IEEE Gold Book.

Variable speed drives (VSDs) are widely used in various applications mainly in process industry need constant rotational speed. It is developed from power electronic components thus saving energy in its operation. Unfortunately it is susceptible against power quality problem for example voltage sags. The VSD may be disruption or drop out when it is supplied by voltage sags and it is determined by sag characteristics. This study is to investigate effect of voltage sags Types I, II and III on VSD through laboratory testing. The voltage sags characteristics are generated from voltage sag generator (Shaffner 2100 EMC).  The effects are presented in susceptibility curves in disruption and drop out conditions. The curves resulted are evaluated by standard curve recommended. Test results show that voltage sag Type I cause the VSD disruption only, whereas two types sag other result in the VSD disruption and also drop out. Evaluation results explain  a few test points are in operation area f...

Power quality is a major concern in electrical power systems. The power quality disturbances such as sags, swells, harmonic distortion and other interruptions have impact on the electrical devices and machines and in severe cases can cause serious damages. Therefore it is required to recognize and compensate all types of disturbances at an earliest to ensure normal and efficient operation of the power system. To solve these problems, many types of power devices are used. At the present time, one of those devices, Dynamic Voltage Restorer (DVR) is the most efficient and effective device used in power distribution system. In this paper, design and modeling of a new structure of multifunctional DVR for voltage correction is presented. The performance of the device under different conditions such as voltage swell, voltage sag due to symmetrical and unsymmetrical short circuit, starting of motors, and voltage distortion are described. Simulation result shows the superior capability of pr...

Es de gran importancia conocer cuáles son las causas  para que se presenten sags en las barrajes de distribución, debido a que la afectación sobre los clientes industriales es de carácter relevante. Por esta razón se planteó  una metodología para buscar la correlación existente entre sags y los eventos ambientales u operativos del sistema de distribución. A manera de ejemplo, se aplicó en tres subestaciones, las cuales se encuentran ubicadas en diferentes sectores de la ciudad. Para el desarrollo de esta metodología, se realizó la correlación de los datos mediante la implementación de tablas dinámicas y programación en Access, donde se evidenció qué tipo de eventos son los que tienen un mayor impacto sobre los clientes. De acuerdo a los resultados obtenidos se sugiere algunas recomendaciones para mitigar este tipo de eventos en el sistema de distribución.

Historical reliability assessment, which is based on past real data, is vital for utilities since it reflects the system's operational behavior best. Therefore, most utilities prefer historical reliability assessment rather than a predictive assessment. This paper includes two major parts; the first part analyses the historical data for four feeders sector of the Bosporus Electricity Distribution Incorporated distribution grid based on their historical collected data, while, the second part of the paper uses the analyzed historical data as a reference input for the Monte Carlo simulation method to assess the future reliability analysis. The results show that the proposed reliability assessment methodology is a powerful tool for the future reliability assessment of power distribution grids.

En este artículo se presenta una metodología para ubicación óptima de condensadores en sistemas de distribución de media tensión, considerando incertidumbre  en la demanda. La incertidumbre en la demanda es simulada usando un flujo de carga probabilístico, el cual fue implementado con base en el método de la cadena, usado para resolver el problema operativo en el método de Montecarlo. Como método de optimización se usa una versión modificada del algoritmo genético, denominado Chu Beasley. Con el fin de potenciar  el método de optimización  se usan factores de sensibilidad que establecen una relación entre la potencia reactiva y las pérdidas del sistema. Para verificar la validez de la metodología, se usa un sistema de prueba de la literatura, con lo cual se concluye que el flujo de carga estocástico determina un valor medio de la demanda, obteniendo resultados similares a los obtenidos  con las versiones que usan flujos de carga determinísticos.  

Cada día es más importante el uso del computador en el análisis de los problemas en ingeniería eléctrica; es igualmente importante, estimular la aplicación de herramientas de computador de uso general (plataformas de desarrollo matemático) en la implementación de soluciones de ingeniería. En este artículo se presenta una caja de herramientas (toolbox) desarrollada en una plataforma de desarrollo matemático de distribución libre llamada Scilab, con el propósito de servir de base para el análisis de sistemas de potencia. Así mismo, se hace una descripción general de Scilab y los algoritmos de análisis de sistemas de potencia a implementar en la caja de herramientas, que permite realizar análisis de sistemas de potencia en estado estable incluyendo análisis de flujo de carga, cortocircuito, estabilidad y despacho económico.

This paper presents a methodology in order to evaluate the security of electrical industrial systems considering security, quality, reliability and availability factors and the system response to sudden disturbances such as short circuit and harmonics. The models proposed using the probabilistic networks theory: Bayesian Networks and Generalized Stochastic Petri Nets. The obtained results allow the identification of hidden failures and erroneus coordination of protection. The models are tested on the IEEE 493 system proposed by the IEEE Gold Book.

This article presents a comparative analysis of various indicators that evaluate the impact of a distributed generator (DG) connection in a power distribution system. The goal is to select indicators to have an effective tool for studying and selecting alternatives for size and location of the DG. This analysis is performed on the IEEE 33 test system, considering mean and hourly values for power generation and load demand.

En la actualidad, se vive una época que contagia a todo el mundo de vivir la experiencia de ver participar a la selección de fútbol de su país en el Mundial de Brasil 2014. Esta situación abarca la probabilidad de clasifi cación de las selecciones sudamericanas a este importante evento de talla mundial. Para recrear este fenómeno se determinó utilizar el método de simulación de MonteCarlo (MC), que permite obtener soluciones de problemas matemáticos o físicos por medio de pruebas aleatorias. Con la implementación del método de simulación MC en las eliminatorias al Mundial 2014, se determinan las diferentes probabilidades que tienen las selecciones sudamericanas participantes en el certamen, de obtener un cupo directo rumbo a Brasil, tomando como referencia las últimas dos fechas de este evento,recreándolo n-ésima veces acercándolo a la realidad. Del análisis de las probabilidades de clasifi cación de las selecciones de Uruguay, Ecuador y Venezuela, y bajo el marco referencial del cu...

Historical reliability assessment, which is based on past real data, is vital for utilities since it reflects the system's operational behavior best. Therefore, most utilities prefer historical reliability assessment rather than a predictive assessment. This paper includes two major parts; the first part analyses the historical data for four feeders sector of the Bosporus Electricity Distribution Incorporated distribution grid based on their historical collected data, while, the second part of the paper uses the analyzed historical data as a reference input for the Monte Carlo simulation method to assess the future reliability analysis. The results show that the proposed reliability assessment methodology is a powerful tool for the future reliability assessment of power distribution grids.

In a distribution system, reliability index is significant to calculate system performance in continuosly distribute the electricity power to consuments. Fedeer analysed by researcher is the main electricity distributor in Tambak Aji industrial area, a developing industrial area. This research is needed to be conducted to ensure the frequent blackout is known and minimalized along with increasement of load number in the feeder. Using section technique method which divides feeder section based on sectionalizer number and detailed calculation in each load point, device failure rate, the length of conductor, and disturbance repairement duration. It was obtained Randu Garut 3 feeder reliability index of SAIFI of 1.759 faults/year, SAIDI of 4.547 hours/year as CAIDI of 2.585 hours/year.

The research on reliability index of a feeder aims to evaluate the reliability level of a feeder using the Reliability Index Assessment (RIA) method. This method evaluates the reliability of a 20 kV distribution network by calculating the reliability indexes of each load point. The evaluation results show the reliability index value per section of the Kumpai Feeder at PT. PLN (Persero) ULP Siantan within one year. The SAIFI values are 0.0092; 0.0012; 12,477; 0.0596; 0.0204; 0.0470; 0.0155; 0.0728, the SAIDI values are 0.0277; 0.0042; 37,746; 0.1862; 0.0741; 0.1524; 0.0493; 0.2209, the CAIDI values are 3.0108; 3.5; 3,025; 3.1241; 3.6323; 3.2425; 3.1806; 3.0343, the MAIFI values are 0; 5,480; 0.2145; 0.0020; 0.0038; 0.0042; 0.0006; 0.0014. The calculation results show that the 20 kV distribution system at PT. PLN (Persero) ULP Siantan at the Kumpai Feeder can be categorized as unreliable. Because the SAIFI value of this feeder exceeds the standard set by PT. PLN (Persero) which are 12...

In this study, the reliability assessment of Medium-Voltage (MV) distribution network is investigated. The study examines one practical part of the MV network in the North East of England. The network used in this study is the radial distribution system, which represents typical urban distribution systems consisting of residential and industrial customers. The degree of reliability of supply is measured by the frequency, duration and magnitude of disturbances to the electricity supply. Both system indices and system worth indices are calculated and evaluated. In addition, the degree of reliability of five case studies is conducted, which can investigate the effects of automation, ageing and load growth.

Para encontrar las condiciones operativas de los sistemas de distribucion tradicionalmente se han considerado flujos de carga radiales debido a las caracteristicas topologicas de la red, las cuales se han evaluado bajo condiciones deterministicas. Sin embargo en los ultimos anos debido a la incorporacion de generadores distribuidos, el diseno de redes levemente enmalladas y el desarrollo de Smart Grids, es importante emplear flujos de carga que se adapten a la perdida de la naturaleza radial de la red y que consideren aspectos estocasticos de la generacion y la demanda. Con el fin de solucionar el problema del flujo de carga probabilistico para redes levemente enmalladas, en este articulo se presenta una comparacion de tres algoritmos: el metodo de dos puntos, el metodo de tres puntos y simulacion de Montecarlo. Los tres algoritmos son usados en conjunto con el metodo de la cadena. Para verificar la efectividad de los metodos se emplea un sistema de distribucion de 69 nodos. Esta co...

The breakdown of electrical energy can be caused by the unwanted failures that occur in the electric power system, especially in the distribution system, and have an impact on service continuity which can be a permanent failure, temporary failure, three phase short circuit failure, double phase short circuit failure, and black out. To anticipate this, a study needs to be done to analyze and find out how well the distribution system reliability index. Determination of the analysis was done by the method of data retrieval related to the analysis variable. Besides, in determining the results of the analysis, calculations using System Average Interruption Frequency Index (SAIFI), Customer Interruption Frequency Index (CAIFI), System Average Interruption Duration Index (SAIDI) and Customer Average Interruption Duration Index (CAIDI) analyses were performed. Based on the reliability of the distribution network, the SAIFI and CAIDI maximum threshold value setup by PT. PLN (The National Electricity Company) at the Semangga substation each worth 3.00 failures/customer.year and 3.00 failures/customerr while SAIDI and CAIDI each worth value of 3.40 hours/customer.year and 3.40 hours/customer.failure. All feeders installed at Semangga switch substation in realization gives reliability indices smaller than the target that has been set., it is mean that 20 kV medium voltage air line distribution system at Semangga switch substation still reliable and the duration of the failure time for each feeder was an average of 3 minutes of each failure and the number of failures every month was an average of 15 times of each feeder.

Regular and reliable access to energy is critical to the foundations of a stable and growing economy. The Nigerian transmission network generates more electricity than is consumed but, due to unpredicted outages, customers are often left without electrical power for several hours during the year. This paper aims to assess the present reliability indices of the Nigerian transmission network, and to determine the impact of HVDCs on system reliability. In the first part of this paper, the reliability of the Nigerian transmission system is quantified by building a model in DIgSILENT PowerFactory and carrying out a reliability study based on data provided by the Nigerian transmission-system operator. Both network indices and load-point indices are evaluated, and the weakest points in the network are identified. In the second part of the paper, an HVDC model is built and integrated into the existing network at the locations identified by the reliability study. A comparative study using tw...

This paper investigated the tripping profile of the 33 kV feeder of Ugbowo 2 x 15 MVA, 33/11 kV electric powerdistribution network. The annual data of daily tripping of the 33 kV feeder from September 2019 to August 2020were collated and collected from the Ugbowo injection substation. The daily outage of the 33 kV feeder was usedto compute the monthly and yearly tripping profile of the sub-transmission line (33 kV feeder) of the Ugbowoinjection substation. The monthly and yearly failure rate, MTTR, MTTF, MTBF, availability, unavailability, SAIFI,SAIDI, ASAI, ASUI, etc. for the period of twelve (12) months were analyzed using the Load Point Indices (LPI)and Microsoft Excel was used graphically to interpret the results of the tripping profile of the 33 kV feeder. Theresults obtained from the analyses of the 33 kV feeder of the network showed that yearly failure rate, MTTR,MTTF, MTBF, unavailability, availability, SAIFI, SAIDI, ASAI and ASUI were 4.32%, 6.520 h, 23.148 h, 29.668h, 21.9...

The significance of a reliable distribution system is hinged on the fact that even if the generation and transmission of a power system are highly reliable, an unreliable distribution system will mean that there will be poor supply of energy to the consumers. Therefore, there must be ways of measuring the reliability of power distribution systems according to given standards in order to help inform the system engineers on the causes of interruptions. This will in turn help in proffering methods of accomplishing a more reliable distribution system. There are established basic methods of assessing the reliability of this system and different researchers engage the one best suited for the analysis they intend to carry out. Moreover, going through previous published works on distribution system reliability evaluation, insight is given into why a distribution behaves below standard and how it could be possibly improved. This paper presents an overview of the basic methods used in reliabi...

Restructuring and recent developments in the power system and problems arising from construction and maintenance of large power plants, increasing amount of interest in distributed generation (DG) source. Distributed generation units due to specifications, technology and location network connectivity can improve system and load point reliability indices. In this paper, the allocation and sizing of DG in distribution networks are determined using optimization. The objective function of the proposed method is to improve customer-based reliability indices at lowest cost. The placement and size of DGs are optimized using a Genetic Algorithm (GA). To evaluate the proposed algorithm, 34-bus IEEE test system, is used. The results illustrate efficiency of the proposed method.