Rethink Eskom maintenance strategies

Rethink Eskom maintenance strategies from Engineering Dynamics

By: Engineering Dynamics  11-27-2008
Keywords: Preventive Maintenance, Laser Alignment, Vibration Analysis

Rethink the Maintenance Strategies in Eskom

With all the Eskom Power Station units down, planned or unplanned, the time is ripe for a greater emphasis on Condition Based Maintenance (CBM). Everyone is aware of Eskom’s strategic goal of "90-7-3" or 90% availability, 7% planned and 3% unplanned outages for generation units, but no mention of the very important aspect of CBM. The percentage availibility and the planned outages can be improved with a more aggressive approach to CBM compared to the past.

Any person with a background in maintenance engineering will know that in a plant like a power station an optimimum mix of three important maintenance strategies should exist. There are proven methods to determine the criticality of equipment and then to develop the appropriate maintenance strategy for the expected failure modes. The three main strategies are planned, unplanned or breakdown and condition based maintenance (CBM). All research and case studies have shown that CBM should be the preffered strategy on the majority of equipment encountered. The unplanned breakdowns will always be with us, but is fuelled further by the local skills shortage.

To follow a Condition based maintenance strategy, advanced technology like vibration analysis, oil analysis, infrared scanning, performance monitoring and many others are required. Measurements must be done a regular basis to build a historic database. The trends of the measured parameters are closely watched by warning and alarm levels that are intelligently set. Eskom has build vast databases over decades of these trends and it can assist to replace a planned maintenance task with a CBM inspection task that will provide feedback on the condition of the equipment. A further factor is that faults are included each time a machine is reassembled after a planned task, even if nothing was found wrong. The old adage of "if it ain’t broke, don’t fix it" must become the norm. There is ample proof that planned maintenance is the more expensive option compared to CBM. Money spent here could be returned to the consumer in the form of lower energy cost increases and a longer life expectancy for equipment in power stations. Condition Based Maintenance is the future!

Keywords: Laser Alignment, Preventive Maintenance, Vibration Analysis, Vibration Analyzer, Vibration Sensor

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