By Sandra Di Matteo, Bentley Systems director of application advantage, asset management and operations
Utility organisations today have a large number of ageing assets, nearing the end of their original as-designed life. Regulatory compliance demands proof you know what and where your assets are and that assets are being maintained properly to ensure they are safe and in good operating order. Detailed analysis and records are required to justify budgets.
It is not surprising then that utilities have been part of the evolution of big data and the internet of things, collecting data related to asset health from sensors and other intelligent monitoring devices, and transmitting operational and condition data through networks, servers, and services. In addition, drones are now being used to inspect and assess the condition of transmission and distribution lines as well as substations.
This ‘big data’ can be processed and analysed to spot trends, help predict events, and formulate reliability and asset life extension strategies. Asset health indexing methodologies empower utilities to make defensible asset investment decisions; and asset health indexing software is being leveraged to automate the analysis and ensure sustainability of the process.
Risk and reward – extending the life of utility assets
Some assets warrant real-time or near real-time condition monitoring to ensure they do not fail. This is because their risk profile indicates the consequences of failure are severe. Other assets are analysed in groups by type of asset, location and other conditions to determine what action to take to ensure reliability.
With a large number of assets nearing end of life, some utilities are using alternatives to pre-emptive replacement. For some assets, if the condition is being managed on a day-to-day basis, the asset life can be safely and reliably extended. Asset health indexing can help make the decision to extend the life, considering:
• What is the overall health of the asset?
• Can the equipment systems and components be monitored and at what cost?
• Can condition monitoring be done remotely or online? Can drones be leveraged to inspect the equipment economically?
• Will spare parts be available?
• On wear related components, can we predict end of life? We can slow deterioration with preventive maintenance, but eventually, the component will wear out and fail.
• What economic factors must be considered (depreciation, operating and maintenance costs)?
Extending the life of an asset can be a low-cost alternative to capital replacement; with an increasing number of utility assets nearing end of life, asset health indices can provide a safe and reliable solution to extend asset life as well as satisfy regulator demands for proof of compliance as well as justification for rate cases/budgets.
What is an Asset Health Index?
An asset health index uses asset condition and risk to drive short-term maintenance and long-term capital replacement strategies. It provides you with a consistent way to compare the overall asset health of utility assets (and asset classes) using big data and predictive analytics. Typically the index is from 1 to 100 where 100 is optimal health.
The calculation algorithm is defined for a class of assets, and then an index number is calculated for each individual asset. For example, the health index for autotransformers might be based on age, maintenance history, load, dissolved gas analysis, etc.; the higher the index, the better the health.
You could calculate overall health index for a substation, based on the health indices of all the transformers, breakers, switches, and so on, that are in that substation. The calculated index is an indication of how close the asset is to the end of its useful life, and how likely the asset is to fail over the medium term.
Value of Asset Health Indices
Originally, health indices were developed to help organisations predict when assets were going to need to be replaced, and from that what the projected capital budget should be for the next five or 10 years. More recently, usage has extended to include more strategic plans such as the long-term strategic asset management plan recommended by the new international asset management standard, ISO 55001.
Ultimately, organisations use asset health indexing to make data-driven repair and replacement decisions that are based on the facts, not on whoever complains the loudest or has the ear of the executive.
Where Asset Health Indexing fits into the process of managing assets
Asset health indexing is part of the strategic asset management plan (SAMP) and the ongoing asset performance management process. It starts with your corporate business strategy and your corporate policy for managing your assets, and takes into account projected future demand (for example, reducing your carbon footprint, ensuring high reliability, and considering factors like population growth or a decrease in demand due to local solar usage.
Health indices assess current capacity and health of your asset base, providing a snapshot of current health, and an indication of how that health has been trending in time given your recent CAPEX and OPEX budgets.
In the short term, the asset manager might be able to cut budgets and save money; but if the quality of the capital asset is decreasing due to under investment, there is an increased risk of failure. By using a more sophisticated measure of asset health related to condition, asset managers can have a fact-based defensible discussion with regulators and company executives about the right levels for capital and operating budgets.
Useful for more than just annual budgeting
By trending health indices in time and correlating them with failure rates and maintenance costs, management can use the health index to help decide whether a major refurbishment program is more effective than asset replacement. Asset health indices change the way maintenance programs are executed. An engineer responsible for a major program needs to know if taking one system out of service is going to create a situation where the peak load is going to land on a system in poor health, and avoiding the system in poor health becoming a single point of failure.
There is a limit to how far we can push health indices into regular maintenance. The data sources for both are often similar, but for day-to-day asset performance management, we need to monitor and trend asset condition, understanding the condition degradation and triggering corrective work that needs to happen in days or weeks, while a health index is a number used for longer term planning. Condition indicators need to react to data in near real time, while health indices are typically only generated monthly, quarterly, or yearly. This longer-range assessment and planning requires statistical modelling. Different asset health models are required for different asset types to account for variation in context.
The decision to implement asset health indices and to automate them can have a significant positive impact on asset and network reliability, enable you to develop a better overall multi-year strategic asset management plan, and establish annual CAPEX and OPEX budgets based on delivering value at an acceptable risk without degrading the overall health of your asset base.