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Condition Criticality Risk Rating and Condition Monitoring in a Distribution Network. PAUL DYER DAVE OPENSHAW London Electricity Group. What am I going to talk about ? Risk Management Maintenance strategies Plant specific diagnostics What are the benefits Summary.
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Condition Criticality Risk Rating and Condition Monitoring in a Distribution Network PAUL DYER DAVE OPENSHAW London Electricity Group
What am I going to talk about? Risk Management Maintenance strategies Plant specific diagnostics What are the benefits Summary
Ensure safety of staff and members of the public • Prevent interruption to supply • Extend the useful life of the asset • Ensure that the most cost effective solutions in place • Enable informed asset replacement policy
As New m = Maintenance or Replacement Window Asset Condition f = Critical Failure (or Uncertainty) Period m + f = ‘P-F’ Interval Risk-Averse Maintenance / Replacement Strategy Potential Failure (Fails Condition Acceptance Criteria) Optimum Maintenance / Replacement Strategy Unacceptable Risk of Failure Hi-Risk (Reactive) Maintenance / Replacement Strategy Functional Failure m f Time or Duty
FOR Considered to be cheap No policy to develop No routine maintenance to budget for AGAINST Safety risk Unscheduled down time Damage to plant Teams always to be ready Loss of confidence Reactive
FOR Easy to predict labour and plan Can ensure maintained before failure AGAINST Not easy to predict failure Easy to over or under maintain Time based
FOR Tailored to actual usage Minimises work AGAINST Needs development work to set duty levels Requires hours run or other duty counters Duty based
FOR Tailored to plant condition Minimises work and knowledge of plant condition AGAINST Needs development work to set condition levels Requires diagnostic equipment Requires some skill to assess condition Condition based
Transformer diagnostics • Moisture and dielectric tests • Dissolved gas in oil analysis • Furfuraldehyde analysis • Hydran on/off line • Metal in oil • Particle analysis
Maintenance strategies Switchgear So what diagnostics do we have available? 1. Discharge • Transient Earth Voltage monitoring • Ultrasonic detection • Radio frequency detection • Discharge sensitive gel
Maintenance strategies Cable diagnostics Why are we interested in cables? • Main cause of loss of supply • Failure is common • Adversely affects KPIs • Main nuisance to customers
Maintenance strategies Cable diagnostics So what can we do? • Monitor failures • Off line partial discharge tests • On line partial discharge monitoring
SUMMARY • What measurements are important? • Evaluate the risk to the system • What data tells me most about equipment operating condition? • Do I need to take measurements from each item • How much will it cost ? • How much time interpreting the results? • Will the measurements be acted upon?
Maintenance strategies THE END Any questions?