Improving reliability whilst reducing maintenance costs is the ultimate goal. Seoras Shaw, Product Manager at Quartzteq, part of the Quartzelec Group, explains why Lifeview® condition monitoring is increasingly being adopted by owners of large rotating machines to measure parameters relating to insulation failure.
The global power chain is dependent on large high voltage rotating electrical machines for mission-critical tasks which when purchased new, cost hundreds of thousands of pounds. Often expected to have ‘arduous’ lives, they are designed to deliver many decades of reliable service across industry and infrastructure; generating electricity, driving production lines, for utilities and transport applications or mining and extraction and in hazardous environments. The problem is that they start to deteriorate from day one and if left untreated significant failures can occur.
All high voltage motors and generators are susceptible to vibration, torque, thermal cycling, corrosion, and critically partial discharge. Visual inspections and scheduled maintenance help identify issues but are intrusive and with numerous large ‘aging’ motors in everyday use a more scientific approach is needed.
Quartzteq’s Lifeview. condition monitoring solution, ostensibly developed around partial discharge analysis, is a flexible, modular, and proven approach to evaluating the health of HV rotating electrical assets. Offering both online and offline monitoring options, assorted sensors and modules – to measure partial discharge, tan delta, rotor flux or shaft voltage and current – can be attached as part of an outage or permanently installed on rotating assets to capture data and create a detailed analysis of the insulation condition of each machine.
Partial discharge
Partial Discharge is a localised high frequency discharge which occurs when the electrical field of the equipment breaches the breakdown strength of the insulating material or gaseous insulation voids and can excessively further weaken and damage any insulating material. It is difficult to identify using traditional testing methods, the damage is progressive, and it can result in catastrophic failure if not detected and effective action taken. Significant stator earth damage often results in weeks of downtime and major repair expenditure anywhere between Åí400k to millions.
Following the development of the partial discharge element of the Lifeview. range, rotor flux and shaft voltage/current measurement capabilities were added to the online monitoring equipment range, allowing users to determine bearing and rotor inter-turn insulation condition during operation.
Offline systems are typically used during regular maintenance programmes and can detect issues during an outage, but constant online monitoring is being increasingly implemented due to there being no interruption to production.
Data interpretation
With data being collected over time, careful analysis can determine the exact insulation condition of a machine, with the most recent data being compared to established baselines.
Professional interpretation of the data is also vital, and the Quartzelec Group boasts over 100 years of experience in rotating machine design and fault analysis from an OEM perspective. Reports and recommendations from the experienced team of specialist engineers help make informed maintenance decisions thus preventing costly breakdowns whilst optimising machine lifespan.
The financial return
The cost of implementing a Lifeview. condition monitoring solution is minimal when comparing the potential costs of an undiagnosed insulation issue, and when combined with an ongoing maintenance programme offers real value for money – particularly when data analysis could prevent a critical failure, avert expensive repair bills and potentially many months of lost productivity. Due to these production saving benefits, insurance companies are increasingly taking a real interest in the advantages that ongoing monitoring delivers and where detailed machine performance data is available, the reward can subsequently be significantly reduced premiums. This means that the ‘payback time’ is often relatively short.
The future
Around the globe owner/operators are increasingly discovering the real benefits to be made by implementing online monitoring alongside ancillary and critical plant maintenance. This achieves an informed and cost-effective maintenance strategy that allows them to focus on driving the business forward removing the risk of a significant failure of a critical rotating machine that could have serious implications to operators and business stakeholders.
www.quartzelec.com | t: 44 (0) 1788 512512
jody.townsend@quartzelec.com / seoras.shaw@quartzelec.com