Utilities
Utilities Information
By implementing solutions to mitigate defects and asset failures on a continual basis, is the tried and true method for improving asset reliability, quality, and productivity performance.
If you’re still not sure where to start, try the 1% rule, as coined by Winston Ledet. Winston and his team in the United States who ran a computer model, which showed that if you turn 1 out of every 100 reactive work orders into a defect elimination focal point and follow through with the analysis and then the solution recommendations, you can reduce your reactive work order count by 37.5% over three years. We must insert the rate at which your team can retire defects will depend on your organizational maturity, training, and bandwidth to process RCA and De.
Regardless, the key is continuous improvement.
Utility Asset Reliability: AER-Aligned REPEX Evidence for the Regulator's Review
TMG works across the four utility verticals, electrical generation, electrical transmission and distribution, natural gas distribution, and water and sewer. The deepest engagement sits with electrical T&D, where the AER's Industry Practice Application Note for Asset Replacement Planning anchors every REPEX submission in probabilistic life-data analysis. TMG is the independent verifier of the Weibull MLE work that underpins those submissions, with the methodological rigour and regulator-grade documentation the AER expects when reviewing multi-hundred-million-dollar replacement programs.
Aligned with every framework your asset programme has to satisfy
The methodology and documentation we deliver is configured against the working set of standards and regulatory expectations that govern utility asset management across electricity, gas, and water sectors.
Four utility verticals, one risk-based asset-management discipline
The regulatory frames differ, the asset classes differ, the failure mechanisms differ. The underlying discipline is the same: model the probability of failure of every meaningful asset class, multiply against consequence, and optimise the replacement programme against lifetime cost. TMG works across the full utility mix.
Electrical Generation
Thermal, hydro, gas, and renewable generation assets carry long service lives, high-consequence failure modes, and asset registers that span multiple decades of installation. Reliability-centred maintenance, condition-based monitoring, and life-data analysis underpin the operating strategy.
Electrical Transmission and Distribution
Poles, transformers, switchgear, conductors, services, and protection systems make up the bulk-population asset classes the AER ARP framework targets. REPEX submissions live and die on the quality of the probability-of-failure modelling and the defensibility of the Weibull parameters that drive it. This is where TMG concentrates.
Natural Gas Distribution
Steel, cast iron, polyethylene, and copper mains networks regulated under AS 4645, with overlay safety oversight from jurisdictional safety regulators (ESV in Victoria, equivalents elsewhere). Cathodic protection, leak survey, and risk-based mains replacement are the working disciplines.
Water and Sewer
Trunk mains, reticulation, pump stations, and treatment assets governed by WSAA codes and state-level economic and safety regulators. The same probabilistic life-data discipline that drives electrical REPEX applies to water mains renewal programs, with the same statistical methods and the same data-quality considerations.
Weibull life-data analysis is the mathematical foundation the regulator expects
The AER's Industry Practice Application Note for Asset Replacement Planning, refined for the 2024 regulatory cycle, anchors every REPEX submission in probabilistic failure modelling. The expectation is explicit: distribution and transmission businesses model each high-volume asset class as a population whose individual members carry a quantified probability of failure that evolves with age and condition. The optimal replacement year for each asset is the year that minimises lifetime cost subject to risk constraints, with the cost-of-failure dimension scaled to the consequence the asset's failure would impose on the network. For TMG's detailed treatment of the underlying methodology, see the Weibull and failure-data analysis service page.
What the ARP Note requires
The AER expects each high-volume asset class to be modelled as a population of individual assets, each carrying a probability of failure that evolves with age and condition. The optimal replacement year is the year that minimises lifetime cost subject to risk constraints, with consequence of failure scaled to the criticality of the asset. The benefit-cost ratio approach drives every defensible submission.
Weibull as the working method
Parametric life-data analysis, typically two or three-parameter Weibull, is the mathematical method the framework expects. Shape parameter beta characterises the failure mechanism. Scale parameter eta anchors the calendar-time location. Maximum-likelihood estimation produces the parameter set; the failure curve integrates against consequence to generate the asset-class risk-cost trajectory the REPEX optimisation operates on.
Independent verification
Distribution and transmission asset registers begin at a finite past date, typically the year the register was digitised. Assets installed earlier but still in service create left-truncation. MLE that ignores left-truncation biases eta upward by 15 to 30 per cent and delays optimal replacement timing by years per cohort. TMG provides the independent methodological assurance the AER expects when reviewing the probabilistic evidence underpinning a multi-hundred-million-dollar REPEX program.
The software platform TMG operates for REPEX-grade Weibull work is the Isograph Weibull Module, which handles two-parameter, three-parameter, mixed-Weibull, competing-risks, and left-truncated right-censored maximum-likelihood estimation with full Fisher-information and goodness-of-fit diagnostics. The module integrates directly into the Availability Workbench environment TMG uses for the broader reliability-engineering programme, so the same parameter set that underpins the REPEX submission also drives the lifecycle-cost, maintenance-strategy, and availability-simulation work that follows.
An independent verification practice, not a data-supply role
TMG does not own your asset register and does not author your REPEX submission. We provide the third-party methodological assurance the regulator expects, on the specific quantitative work that underpins the most expensive replacement programme on your operating plan.
Weibull-driven REPEX submission support
TMG verifies the Weibull MLE work that underpins your AER submission across the bulk-population asset classes: poles, pole-top structures, distribution transformers, ground-mounted transformers, switchgear, conductors, services. Verification covers parameter estimation, censoring treatment, left-truncation correction, and the regulatory-grade documentation the AER reviews against.
Left-truncated right-censored (LTRC) MLE
For asset cohorts with installation dates predating the digital asset register, naive MLE materially overstates eta. TMG implements the correction within the same maximum-likelihood framework, with full Fisher-information and diagnostic-test coverage. The result is a defensible parameter set that survives regulator scrutiny.
Competing risk separation for conditional-failure vs end-of-life
On assets with multiple failure modes (insulators, conductors, joints), the population-level failure-time distribution is a competing-risks mixture. TMG separates the conditional-failure and full-life-failure regimes using Nelson's conditional probability method, so each REPEX driver is parameterised against its own physically meaningful failure mode.
Optimal inspection-interval modelling
For inspection-driven asset classes (poles in particular), the Barlow-Proschan optimal inspection-interval framework determines the interval that minimises lifetime risk-cost. TMG implements the model on the same Weibull foundation that drives the REPEX submission, producing inspection-program economics that the regulator can audit end to end.
What AER-aligned REPEX verification delivers
The figures and descriptors below characterise the outputs of TMG-verified REPEX work in the Victorian and broader National Electricity Market regulatory environment. Verification depth in any given engagement scales with the asset-class population size, the left-truncation extent in the dataset, and the regulatory exposure of the submission.
Engage TMG for your utility asset-management programme
The Mantua Group delivers independent Weibull life-data verification for AER REPEX submissions, with parallel asset-reliability practice across natural gas distribution and water and sewer networks. We bring the analytical rigour, the regulatory familiarity, and the implementation discipline that turns a probabilistic model into a defensible regulatory submission.
- Reliability Engineering and Life Prediction
- Reliability Program and Asset Management Assessment
- Root Cause Failure Analysis (RCFA)
- Failure Mode Effects and Criticality Analysis (FMECA)
- Weibull Data Analysis
