Mehairjan - Risk-Based Maintenance for Electricity Network Organizations

Rotterdam, The Netherlands

Ravish Preshant Yashraj Mehairjan

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The central theme in this book is the management of maintenance of assets in the electricity network sector and, more specifically, on electricity networks for distribution. The concept of maintenance has existed a long time and has evolved along this period in various industrial applications as well as research areas. In the electricity network sector, maintenance is gradually gaining more interest on management level as part of an integral management aspect. This is mostly because of the changing and profoundly challenging environment in which electricity network companies have to operate nowadays. This changed environment is brought about by, for instance, the sector reform, massive uptake of distributed generation devices, disruptive changes in the control and communications equipment used in the network and increasing regulatory and funding pressure that is being placed on electricity network organisations to justify their management actions and expenditure decisions (IEC White Paper ).

As a consequence, firstly, reliability engineering, seen from a technical point of view, took off as a prevailing discipline. Secondly, followed by the context of controlling costs, seen from a financial point of view, formed an important driver for network companies. Thirdly, a more recent development has been the progress towards a business context, seen from a social and technical point of view, as a driver to balance amongst costs, performance and risks in an integrated and documented manner. Nowadays, the management of the electricity network business speaks about asset management (physical asset management or infrastructure asset management). In Fig. ).

Asset management, as defined in BSI: PAS55 is the systematic and coordinated activities and practices through which an organisation optimally and sustainably manages its assets and asset systems, their associated performance, risks and expenditures over their life cycles for the purpose of achieving its organisational strategic plan (The Institute of Asset Management (IAM) ).

Maintenance management forms an important part within asset management. This book deals with the issues surrounding maintenance management for electricity network companies. Although there are a large number of books and research papers available on maintenance-related topics, however, there still remains a gap for industry-specific views on maintenance of long-term assets. This book aims to link the general management subjects applicable for maintenance to methods, tools and technologies, which can be used for practical purposes in the electricity sector. This approach is not common, as in most available literature the focus is on one single aspect, instead of providing a broader view with practical methods. Furthermore, the majority of developed models and analysed case studies in this book come from real-life electricity network applications.

Maintenance is not a new topic. Maintenance has existed a long time and has changed drastically over the past decades. In general, for maintenance management, the following evolution of issues has been reported:

The changes described here apply mostly to industrial areas such as the process industry and mechanical industries. The developments in maintenance management have been less rapid for the electricity network sector, due to the long lifetime of assets, the lower loading of the assets, gold plating of assets, redundant network design, to mention a few. In fact, it was especially the transmission network that was more mature in terms of maintenance developments compared to distribution networks (which, in the early days, mainly followed corrective maintenance). An international CIGRE survey (CIGRE Joint Working Groups (JWG) 23 and 39 ) published in 2000 showed that preventive maintenance with a predetermined time interval (known as time-based maintenance) is the most common strategy (47%) for transmission networks, followed by offline condition-based maintenance (31%). These percentages are mainly valid for assets such as transformers, lines, towers and substations equipment. For cables and control equipment, corrective maintenance was used as the predominant approach. The responses also varied between regions. Around 50% of the respondents indicated that they performed more maintenance than recommended by the manufacturers, particularly in lower labour countries.

For distribution networks, these numbers are not widely available and maintenance has been managed in a rather ad hoc way based mainly on experience. Furthermore, and more importantly, the lack of a clear maintenance management philosophy became more visible in the distribution networks during the move from price regulation to pricequality regulation (Ajodhia ). Thus, a challenge arose for the electricity distribution networks regarding maintenance management. Finding the right mix of maintenance activities for distribution network assets is a challenge for network companies due to the renewed business environment, where maintenance is not a merely technical issue any longer. Maintenance departments will be expected to function in a broader sense and move away from silos thinking. These days, maintenance departments are required to consider financial aspects and manage maintenance budgets. Furthermore, maintenance processes are required, maintenance and asset key performance indicators (KPIs) are needed, and recourses and skills need to be managed.