Maintenance Strategies in Distribution Systems - Report Example

Maintenance Strategies in Distribution Systems and the Application of the Electrical Preventive Maintenance & Testing Program Author’s name, Institutional affiliation Abstract This report details the findings and analysis of a visit to AADC to study their maintenance strategies in distribution systems and the application of the Electrical Preventive Maintenance & Testing (EPMT) program. Based on the assessment strategy for ELT N301 - Electrical Testing and Maintenance, this report is partly informed by the educational visit that took place on Tuesday 6th November 2012. Maintenance Strategies in Distribution Systems and the Application of Electrical Preventive Maintenance & Testing Program Introduction After getting the assignment we divided ourselves into two groups A and B. I was in group A and we developed a plan to guide our visit to AADC. The group asked me to initiate contact with AADC which I did and linked with Mr. Asha, the Head of Operations in the Power Distribution Department. However, my first visit was not successful I was told that Mr. Asha was attending several meetings and I could only see him after four days of booking an appointment with him. I quickly drafted a letter and delivered to the secretary who confirmed my scheduled pre-visit on phone two days later. We agreed with him and arranged a visit for 6th November, 2012. During the visit, we met the Head of Operations, Mr. Asha and two electrical field engineers who received us well at the reception and led us to the meeting room. We shared our plan and together with the host we came up with a workable program for the visit. The program included a brief background information about the company and detailed information about the department. It also covered the kind of electrical preventive maintenance strategies the department uses in general with specific focus on use of electrical preventive strategies on transformers. We had an open session where all people participated freely and the staff promised they were going to respond very positively. In the process, we learnt that the department of Power Distribution is one the largest in the company with a key objective to provide reliable, efficient electrical power to Al Ain city and neighboring countries. It does this through continuous surveillance of electricity flow within the company networks and maintenance of overhead lines. It has employed technology to detect possible fault lines and adopted systems to restore electricity automatically in case of disruption in supply. This has enhanced availability of power supply and happier customers. The department stills works hard towards ensuring a higher uptime of electrical power distribution networks to cope with expanding populations that push up the demand for electricity. Distribution Maintenance strategies Companies implement maintenance strategies in varying time intervals; on a daily basis, monthly, quarterly or as an organization find it necessary. There exist two principle maintenance strategies according to Kiameh (2003) that are applicable to large companies such as AADC namely reactive maintenance and proactive maintenance. Reactive maintenance is carried out to recover from a failure that was unexpected or that which suitable mechanisms had not been used to avoid or mitigate. Conversely proactive maintenance involves assessing equipment to put them in working states that minimize the probability of failure. As such, proactive maintenance takes two forms; preventive and predictive maintenance. Predictive maintenance uses non-invasive techniques to assess the condition of equipment without introducing any changes in the normal operations where as preventive maintenance involves invasive set of tasks done on equipment to cope with deterioration in performance hence reducing chances of failure. Reactive maintenance poses the risk of downtime as time to recover from failure implies little or no operation on lines that depend on the failure. Moreover, the events that trigger reactive maintenance may be without user control and may precipitate a chain reaction in a company that may render its operations redundant or eliminate customer loyalty. Consider a transformer running dry in a power distribution company substation because of reactive maintenance strategies. The depletion of the oil may not only result in no electricity distribution and dissatisfied customers, but can easily trigger fire outbreak consuming a great portion of the plant that could be too expensive to replace and restore power supply. Proactive maintenance is therefore preferred to reactive maintenance to large companies like AADC. It captures reliability centered maintenance that covers equipment environment, the context of operation, level of user experience combined with regular monitoring of equipment to ensure acceptable level of system performance with respective in aging of equipment. Proactive maintenance thus ensures reduces functional failures, tracks failure modes, failure effects and consequences and aids formulation of consequence reduction tasks. Whereas proactive maintenance is recommended for large companies like AADC may appear expensive to run, the net effect is far more cost effectives than having to fix failures. Keeping acceptable level of transformer oil is much more affordable than replacing a blown transformer with a new one. There is need for emergency response team to provide uninterruptible support to rescue company equipment from potential damages or losses occasioned by malfunctions in electrical systems. EPMT program  Electrical Preventive Maintenance and Testing program provides regulated monitoring processes applied to ensure high reliability of assets[Rya09]. EPMT typically includes analysis of possible and actual failures, repairs, testing, profiling of testing and maintenance data as tactics to minimize risk of failure occurrence or recurrence. EPMT includes physical inspections, removing grime, adjusting and testing equipment to ensure optimal operations for a specified period. This enables identification of components with potential to cause failure hence aid replacements in time. Testing should be guided by industry standards and equipment manuals to keep within realistic typical performance of equipment. Typical testing includes acceptance testing, instrumentation and control systems testing, transformer, ground, circuit breaker, relay and cable testing. Repair of electrical equipment reduces unexpected system breakdowns. Components with high frequency of breakdown like electrical fuses should be readily available in spare. All failure should be analyzed to establish root causes and be resolved. . Consistent Profiling of Maintenance helps monitor aging equipment hence provision of appropriate corrective measures to mitigate failure. Infrared analysis is widely used in electrical systems to detect faulty components or links with potential to failure. These could include circuit overloads, leaking voltage or connection that need to be fixed. EPMT presents numerous benefits like asset protection that extends the utilization period of electrical dissociated electrical hazards [Ass10]. Companies that implement EPMT have high uptime with stable or improved production that results in better profitability due to the power quality control and assurance. Components that are well maintained work optimally hence energy conservation. In addition, it reduces risk management by limiting injuries, fire and associated distribution equipment and systems as well as lowering risk transfer costs as insurance premiums charges are directly affected by the likelihood and impact of risk on the electrical systems[Ass10]. Large companies like AADC should adopt automated Computerized Maintenance Management System that easily and accurately record equipment status data, profile performance trends and keep test results for timely access and review [Kis06]. This enables a well coordinated and distributed forecasting of system reliability metrics that aids maintenance budgeting and production estimates. A typical CMMS includes work break down structures, equipment performance trending analysis, inventory control, asset management, root cause of failure analysis, classification of critical components. Examples of CMMS include EPower Forms and PowerDB. While it is recommended for large companies like AADC to have in-house maintenance team it is important to engage independent experts to offer valuable unbiased preventive maintenance and testing of electrical equipment [Dim09]. Quality testing equipment with accurate and standard calibrations must be used to ensure reliable test results. Maintenance Strategy of a Transformer AADC has a comprehensive maintenance program for its set of dry and fluid-filled transformers covering five key aspects of inspection, infrared imaging, random sampling, testing and routine maintenance. All new transformers undergo inspection transformer to ensure all parts are delivered as procured. The parts to inspect before the transformer is powered include gauges, controls, tank condition and wirings. Inspections are also done weekly on installed transformers by electricians and verified by a field engineer and logged in maintenance records. Infrared Imaging is done to identify hidden cracks, load imbalances, loose and faulty wiring with results on digital display to show relative variations of component state against problems [Int05]. AADC schedules the scanning to be done on all newly acquired transformers and quarterly for existing installations. Random sampling is done by industry certified electricians on transformer fluid who carries out standard test on the fluid at the AADC laboratory at least semiannually and the findings documented to inform the frequency of test on the insulation fluid. The transformers are each scheduled for a routine maintenance at least once a year. Prior to this, they are de-energized and left idle for one week. The activities involves used oil refilling, cleaning bushings, fixing loose connections, checking for leakages, adjusting funs and recharging of gas blankets. According to Levitt (2009), testing of the transformers functional condition includes: winding resistance, power factor, turns ratio, insulation and resistance-dielectric absorption. All work done on maintenance must have signed documentations of all sets of activities and tasks carried out, with suitable recommendations to enhance transformer uptime. AADC has in place a maintenance policy that allows electrical repairs to be done by industry certified persons only and completely discourages unqualified persons to attempt to handle any such repair. Detailed procedures to guide electrical troubleshooting or maintenance require that the equipment under maintenance shall be de-energized with exemption only to if the component under maintenance requires such energy for the operation or where it is infeasible to disconnect electrical power supply. These are safety measures to protect workers and equipment from adverse effects that may be induced by the maintenance tasks. It also requires all sources of energy to be put to safe state like grounding and discharging of capacitors where applicable. Summary and Conclusion The people culture at AADC is an attractive and outstanding show of how organizations can brand and implicitly market themselves. Our visit was successful because by the end of it we were able to draw relations from the industry practices with our course work on electrical maintenance and testing. It was interesting to physically observe different kinds of transformers to buttress the theory we had learnt in class. It was a good exposure to me and is worth repeating in other establishments. Such visits would be more beneficial if they are coordinated from our Departmental Committee more than by student groups. This would give it greater legitimacy and possibly a dedicated team at a company released to guide us. The team we had got interruptions from time to time as they had occasionally respond to their major responsibilities. References Rya09: , (Cruzan, 2009), Ass10: , (Association, 2010), Ass10: , (Association, 2010), Kis06: , (Bagadia, 2006), Dim09: , (Kiritsis, 2009), Int05: , (Interior, 2005), Read More