Modelling the impact of the environment on offshore wind turbine failure rates

For offshore wind turbines to become an economical energy generation option it is vital that the impact of the offshore environment on reliability is understood. This paper aims to model the impact of the wind speed and the external humidity and temperature. This is achieved using reliability data comprising of two modern, large scale wind farm sites consisting of approximately 380 wind turbine years of data. Weather data comes from a nearby weather station and an onsite met mast. A model is developed, using the reliability data, which calculates weather dependant failure rates and downtimes which are used to populate a Markov Chain. Monte Carlo simulation is then exercised to simulate the lifetime of a large scale wind farm which is subjected to controlled weather conditions. The model then calculates wind farm availability and component seasonal failure rates. Results show that offshore, the wind speed will have the biggest impact on component reliability, increasing the wind turbine failure rate by approximately 61%. The components affected most by this are the control system and the drive train. The higher offshore wind speeds appear to cause a higher proportion of major failures than experienced onshore. Research from this paper will be of interest to operators and wind turbine manufacturers who are interested in maintenance costs and logistics

A Systems Approach Towards Reliability-Centred Maintenance (RCM) of Wind Turbines

AbstractWind turbines are a proven source of clean energy with wind power energy harvesting technologies supplying about 3% of global electricity consumption. However there is an increasing demand on maintenance and operational improvements since turbines have been plagued with downtime problems of major components e.g. gearboxes and generators, especially with offshore turbines which are difficult to access. Reliability Centric Maintenance (RCM) is a way of capturing the potential causes of downtime and poor performance by preventing failures and having a proactive approach to operations and maintenance (O&M). However, for a large fleet of turbines, adopting the RCM approach becomes difficult due to the complexities that arise as a result of the interactions between individual elements that make up the system in the product lifecycle. This paper discusses how a systems thinking approach can be used to identify the relevant aspects and possible interactions between the RCM approach and wind turbine gearboxes and also how the gaps that exist within the system can be closed so as to add value to business. The outcome of the paper is a proposal for applying a systems approach to wind turbine gearbox operation and maintenance, optimising the asset value adding contribution at minimal total cost to the operator

Availability Improvement Methodology in Thermal Power Plant

Availability of a complex system of thermal power plant is strongly influenced by maintenance program and component reliability. Various maintenance techniques, likes RCM (reliability-centred maintenance), RBM (risk based maintenance) and CBM (condition-based maintenance), have been applied to improve the availability. Implementation of RCM, RBM, CBM alone or combined RCM and RBM or RCM and CBM is a maintenance technique used in thermal power plants. This study develops an new maintenance methodology integrating RCM, RBM and CBM to increase the availability of thermal plants. The method generates MPI (Priority Maintenance Index) and FDT (Failure Defense Task). MPI is used to determine the priority of components in maintenance program. FDT consists of the tasks of monitoring and assessment of conditions other than maintenance tasks. Both MPI and FDT obtained from development of functional tree, failure mode effects analysis, fault-tree analysis, and risk analysis (risk assessment and risk evaluation) were then used to develop and implement a plan and schedule maintenance, monitoring and assessment of the condition and ultimately perform availability analysis. The results of this study indicate that the reliability, risks and conditions-based maintenance methods, in an integrated manner can increase the availability of thermal power plant

Reliability-Centred Asset Maintenance – A step towards enhanced reliability, availability, and profitability of wind power plants

Reliability and availability are key issues for theimplementation of future sustainable power systems. This paper discusses the need, methods and challenges for maintenance optimization to improve the reliability, availability, and profitability of wind power plants being a major source of renewable energy today and in future “smart grids”. The present maintenance of wind power plants is extensive and costly, especially at offshore sites. The paper discusses approaches to maintenance strategy optimization aiming at reaching cost efficient maintenance and thus enhanced profitability of wind power plants. It presents results from practical case studies utilising the method of Reliability-Centred Asset Maintenance and highlights the factors that impact the benefit of the maintenance strategies. The results show that new solutions for condition monitoring of the drive train and blades in wind turbines can be cost-efficient with respect to the reliability and availability of wind turbines today

Reliability-Centred Asset Maintenance – A step towards enhanced reliability, availability, and profitability of wind power plants

Reliability and availability are key issues for theimplementation of future sustainable power systems. This paper discusses the need, methods and challenges for maintenance optimization to improve the reliability, availability, and profitability of wind power plants being a major source of renewable energy today and in future “smart grids”. The present maintenance of wind power plants is extensive and costly, especially at offshore sites. The paper discusses approaches to maintenance strategy optimization aiming at reaching cost efficient maintenance and thus enhanced profitability of wind power plants. It presents results from practical case studies utilising the method of Reliability-Centred Asset Maintenance and highlights the factors that impact the benefit of the maintenance strategies. The results show that new solutions for condition monitoring of the drive train and blades in wind turbines can be cost-efficient with respect to the reliability and availability of wind turbines today

Asset management strategies for power electronic converters in transmission networks: Application to HVdc and FACTS devices

The urgency for an increased capacity boost bounded by enhanced reliability and sustainability through operating cost reduction has become the major objective of electric utilities worldwide. Power electronics have contributed to this goal for decades by providing additional flexibility and controllability to the power systems. Among power electronic based assets, high-voltage dc (HVdc) transmission systems and flexible ac transmission systems (FACTS) controllers have played a substantial role on sustainable grid infrastructure. Recent advancements in power semiconductor devices, in particular in voltage source converter based technology, have facilitated the widespread application of HVdc systems and FACTS devices in transmission networks. Converters with larger power ratings and higher number of switches have been increasingly deployed for bulk power transfer and large scale renewable integration—increasing the need of managing power converter assets optimally and in an efficient way. To this end, this paper reviews the state-of-the-art of asset management strategies in the power industry and indicates the research challenges associated with the management of high power converter assets. Emphasis is made on the following aspects: condition monitoring, maintenance policies, and ageing and failure mechanisms. Within this context, the use of a physics-of-failure based assessment for the life-cycle management of power converter assets is introduced and discussed

“Diseño de una estrategia para implementar la gestión de activos en la empresa Coopesantos R.L. basado en la norma ISO 55001:2014”

Proyecto de Graduación (Licenciatura en Mantenimiento Industrial) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Electromecánica, 2020La organización Coopesantos R.L., se encarga de brindar el servicio de distribución eléctrica en un área de 1 500 kilómetros cuadrados, donde se encuentran 120 comunidades las cuales se distribuyen en nueve cantones pertenecientes a la provincia de San José y Cartago. Del mismo modo, la cooperativa también ofrece el servicio de info comunicaciones, y desde el 2011 genera aproximadamente el 30% de la demanda eléctrica, por medio del Parque Eólico Los Santos. Debido a la naturaleza de los activos adquiridos por Coopesantos R.L., en los últimos años, además de estar constantemente regulado por la ARESEP (Autoridad Reguladora de los Servicios Públicos), y donde también se deben dar informes de cuentas a los delegados representantes de las comunidades; hace de la Gestión de Activos regida bajo el estándar internacional ISO 55001:2014, idónea para mejorar la eficiencia en el funcionamiento de la institución. Por medio del estudio realizado, se inicia con un diagnóstico para evaluar el nivel de madurez de la cooperativa, con relación a los requisitos pedidos en la norma. Se utiliza como criterio los niveles establecidos por el Instituto de Gestión de Activos (IAM por sus siglas en inglés), organismo creador de la norma PAS 55:2008 predecesora de la familia ISO 55000. El resultado de la evaluación permite conocer los puntos fuertes y débiles de la cooperativa, con lo cual se procede a establecer las recomendaciones para mejorar la gestión integral de la organización por medio de esta herramienta, seguido de un mapa de ruta para proceder con una posible implementación, y finalmente los aspectos donde se demuestra la viabilidad de generar el proyecto. Se concluye, que la nota obtenida en la evaluación es riesgosa para la organización, pero se puede corregir al adoptar un Sistema de Gestión de Activos, donde los temas claves son la comunicación, la toma de conciencia del personal, la cultura organizacional, el seguimiento de los indicadores para la toma de decisiones y control general de las diferentes áreas de la cooperativa. No obstante, se demuestra un liderazgo eficiente, lo cual puede asegurar la aplicación correcta del Sistema Gestión de Activos apegada a la ISO 55001:2014, aunque se debe recordar que se trata de una práctica iterativa y de mejora continua, por lo tanto el compromiso y la perseverancia son vitales para obtener los beneficios proyectados al cumplir la normativa internacional.Coopesantos R.L is an organization in charge to provide the electric distribution service in a 1500 km2 area, where are located 120 towns distributed in nine San José´s and Cartago´s cantons. In the same way, the cooperative offers the infocomunications service, and, since 2011 generates aproximately the 30% of the electric demand, by means Parque Eólico Los Santos (Los Santos wind farm). Because the nature of the assets acquired by Coopesantos R.L. in the last years, besides being constantly regulate by ARESEP (Public Services Regulation Authority), and where accounts reports must also be given to the delegates representing the community; makes the Asset Management governed by the international standard ISO 55001:2014, suitable to improve efficiency in the operation of the institution. Through the project made, it begins with the in initial diagnostic to evaluate the mature level of the cooperative, in relation to the norm´s requirements. The criteria used are the levels established by the Institute of Asset Management (IAM), organization creator the norm PAS 55:2008 predecessor of the family ISO 55000. The result of the evaluation allows to know the strengths and weaknesses of the cooperative, with which it proceed to establish the recommendations to enhance the integral management of the organization through this tool, followed by a road map to proceed with a possible implementation, and finally the aspects where the viability of generate the project is demonstrated. It is concluded that the grade obtained in the evaluation is risky for the organization, but it can be corrected by adopt an Asset Management System, where the key aspects are the communication, staff awareness, organizational culture, indicators monitoring for decision-making and general control of the cooperative´s different areas. However, efficient leadership is demonstrated, which can ensure the correct application of the Asset Management System in accordance with ISO 55001: 2014, although it must be remind that it is an iterative practice and continuous improvement, therefore the commitment and perseverance are vital to obtain the projected benefits by the accomplishment of the international standards

Semi quantitative and fuzzy logic based approach for risk based inspection and maintenance of thermal power plant components

Abstract: This thesis deals with the development of a Risk Based Inspection Programme for the Eskom Fossil Fired Power Stations. This study comes as a result of external and internal factors that affect Eskom from producing electricity to ensure security of supply. Eskom current supplies 95% of South Africa’s electricity needs. AS part of Eskom’s drive to remain financially sustainable Eskom has move to cost reflective tariff model. This model considers all the input costs required to generate electricity and this cost is then passed on the consumer. As part of Eskom’s multi-year price determination Eskom requested a 16% increase for the next five years (2014-2019). This was turned down by the National Energy Regulator (NERSA) and instead Eskom was awarded an 8% tariff increase. For Eskom this means that current funds must be spent wisely. With more than 50% of Eskom’s current running fleet being past the mid-life of their design it means that more maintenance activities need to be carried out on these plants. With a decrease in the tariff Eskom now has to decide on which plants take preference over maintenance activities. The Pressure Equipment Regulations (PER) came into effect in October 2009 and compliance to these regulations are mandatory. The PER requires that Eskom pressure test all equipment regarded as pressure equipment according to the PER on a 3 yearly basis. Currently these pressure tests are carried out on a 6 yearly basis. Should Eskom move to the 3 yearly frequencies it would mean that Eskom would experience some difficulties in ensuring security of supply of electricity to South Africa. The PER however allows the users of pressure equipment to apply a Risk Based Inspection approached to the pressure equipment as opposed to the fixed term pressure testing. This RBI would give the user the latitude to make fitness for service decisions and determine the frequency of test and inspection 3 activities. Eskom has opted to implement a risk based approached to all pressure equipment on within the generating fleet. This thesis looks at the development of the Risk Based Inspection programme. The objective of the thesis is to determine whether the CWA15740 process can be applied within the Eskom environment to ensure compliance to the OHSACT. The thesis also investigates the use of fuzzy logic to determine risk plots for boiler valves. This thesis consists of 9 chapters. Chapter one looks at the current situation that Eskom is faced with both from a funding and statutory point of view. Chapter two is a literature survey that looks the development of RBI and is applications in other industries. Chapter 3 discusses the research approach adopted by the author and it defines the research question and the research objectives. This research follows the case study approach. Chapter fours describes the CWA15740 approach looking at the possible advantages and disadvantages of the approach. Chapter five describes the data gathering process for the data required for the RBI assessment. Chapter six looks at the development of the RBI model and delves into the multi-level risk assessment approach. Chapter seven discusses the outcomes of the RBI pilot that was carried out at Lethabo Power Station. Chapter eight discusses the development of the Fuzzy C Mean (FCM) algorithm to predict valve risk based on the clustering concept. Finally chapter nine discusses the learnings from the research as well as the conclusions that can be drawn and finally, future work based on the findings of the research. The findings of the research indicate that the CWA15740 process is an effective process for the power generation industry given its non-prescriptive approach. This was proven by the successful certification of Lethabo Power Station by an independent Certification Body. Further the FCM algorithm proved that it is possible to predict boiler valve risk using the clustering approach. 4 Finally the research found that by implementing a risk based strategy saving of a minimum of 84% could be achieved. The contributions of this work are twofold. Firstly the development of a Risk Based Inspection process for the fossil Fired power generation industry. To the best of the author’s knowledge the process using the CWA15740 process has not been rolled out at any fossil power generating utility. Typical maintenance processes followed by fossil fired power generating utilities do not include the risk component. This statement is supported by the benchmarking exercise as well as the literature survey. Secondly the use of the FCM algorithm shows that the FCM clustering process can be effectively used to predict component risk. Keywords: Probability of Failure; Likelihood of Failure; Component Damage Mechanism; Fuzzy C Mean; Pressure Equipment Regulation; Conformity Assessment; Multi Level Risk Assessment.D.Ing. (Engineering Management

Modelo para garantia da disponibilidade de turbinas eólicas

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2016.A demanda por fontes de energia renováveis limpas é um fenômeno de escala mundial. O Brasil acompanha essa tendência e, desde 2009, vem incentivando o crescimento destas formas de geração de energia. Particularmente, a energia eólica chama atenção pela velocidade com que se expande no país. Por outro lado, este mercado tem apresentado resultados que precisam ser devidamente analisados. Estudos realizados com parques eólicos em operação no Brasil mostram que muitos destes estão produzindo abaixo do esperado, um problema que afeta o proprietário do parque, em termos de receita; o governo, em termos de planejamento estratégico e fornecimento de energia; e a população, que paga por uma energia mais cara e que não tem ainda a devida garantia de disponibilidade. Em face deste contexto, apresenta-se um Modelo para Garantia da Disponibilidade de Turbinas Eólicas, fundamentado na organização e sistematização do conhecimento, e estruturado em técnicas para prover ações de manutenção. Pretende-se que as soluções desenvolvidas contribuam para adequar a quantidade de energia produzida ao nível da estimada nos diversos parques eólicos já em funcionamento no Brasil. Com o intuito de facilitar e viabilizar a aplicação do modelo proposto, foi desenvolvida uma ferramenta computacional denominada MADE. Tanto o modelo, quanto o software, passaram por um processo de validação, junto a profissionais do setor eólico e da área de metodologia e sistematização, a fim de autenticar sua aplicabilidade e resposta ao problema. Os resultados obtidos indicam que a solução proposta é, de fato, um caminho para suportar a gestão de manutenção com vistas à garantia de disponibilidade dos parques eólicos em operação.Abstract : The demand for clean renewable energy sources is a worldwide phenomenon. Brazil follows this trend and since 2009 has encouraged the growth of these forms of energy generation. Particularly wind power draws attention due the fast expansion in the country. In the other hand, this same market has shown results that must be properly analyzed. Studies of wind farms in operation in Brazil show that many of these parks are producing below the expectations: a problem that affects the owner of the park in terms of revenue; the government, in terms of strategic planning and energy supply; and the people who pay for a more expensive energy and that does not present the due availability guarantee. Given this context, one presents a Model for Availability Guarantee of Wind Turbines, based on the organization and systematization of knowledge, and structured techniques to provide maintenance actions. The solutions presented aims to contribute for the adequacy of the quantity of energy produced by the several wind farms already operating in Brazil. For the purpose of facilitate and make viable the implementation of the proposed model, a computational tool called MADE was developed. Both model and software went through a validation process with professionals of the wind sector and the methodology and systematization area in order to authenticate their applicability and response to the problem. The results indicate that the proposed solution is indeed one way to support the maintenance management to guarantee availability of farms in operation