The efficient management of infrastructure is crucial for a distribution utility in order to supply quality power in today’s time. For long, the sole focus of utilities has been the installation of new equipment and employment of new technologies. However, utilities face several challenges in achieving optimum operational and maintenance standards. In this regard, asset management can help utilities in addressing issues related to ageing assets and reliability due to uncertainty in the power system. Asset management includes procurement planning, quality testing, inspection programmes, condition assessment, maintenance management, refurbishment and replacement of assets, and the adoption of life extension technologies.
Asset management is required throughout the life cycle of an asset. At the initial stage, the chances of damage are very high. With time, the need for maintenance increases in order for the asset to be utilised to its maximum potential. Some parts may even need to be replaced to extend its useful life. But with the asset reaching its final stage, it needs to be phased out by deploying the relevant techniques.
Maintenance comprises the most important part of asset management and can be divided into three categories: corrective, preventive and conditioned-based maintenance. Corrective maintenance is synonymous with breakdown maintenance. It is done when a defect has already occurred. In the case of an outage, data points like load current, voltage, temperature and oil levels are taken into account to restore the equipment. It is a gamble between the cost of repair and the investment required to move out that equipment, whichever is lesser.
Preventive maintenance and condition-based maintenance aim at avoiding failures. The most widely accepted approach, preventive maintenance is time based and only used for offline equipment. Maintenance in this case is done at regular, scheduled intervals. The timeline is prepared based on the service history of the equipment along with the experience of the personnel involved in its operations.
A smarter extension of the preventive approach is the predictive approach. It looks at the health of the equipment by taking into account the cause, symptoms and effect of various performance parameters.
The last and most advanced methodology is condition-based maintenance. It involves the constant monitoring of multiple variables of the equipment. Whenever the condition falls below acceptable levels, the equipment is taken up for maintenance. Such an approach when implemented for high-revenue customers is likely to provide maximum benefit. Though intelligent, the approach is quite expensive and cumbersome.
While maintenance strategies have evolved from the traditional breakdown approach to a condition-based one, it may not always possible to follow only one of these approaches. Keeping reliability in focus, utilities have to strike a balance between various existing approaches. Given the extensive asset base of utilities, condition-based maintenance for all equipment is not humanly and practically possible. Hence, it may be used only for equipment that involves higher repair costs.
Apart from the appropriate maintenance strategy, several other aspects also contribute to the successful maintenance of assets. One such aspect is inadequate design. At times, the design of a particular equipment may not be satisfactory enough to hold up its entire life cycle. In such cases, the specifications of the equipment need to be revised. Another common concern is the poor and insufficient training of personnel operating the equipment. Further, there exist irregularities and inconsistencies in data recording and collection with respect to installation, repair and maintenance of the related equipment. In the absence of accurate records, it is difficult to predict whether the asset needs to be retired or is ready for further use.
In order to make the right decision, it is very important to develop the ability to analyse the complex dependencies between maintenance and renewal actions on the one hand, and costs and the quality of service on the other. Utilities need to optimise the utilisation of their equipment by focusing on the technical and financial aspects. Further, with an increase in the penetration of renewables, variability in the system has increased and so has the need for asset management. Thus, taking into account the financial prudence, utilities must carefully study asset diagnosis and accordingly put into action the relevant mix.