|
42. Meeting in Dublin (7./8.04.2011)AgendaWelcome (Paul Thame)
TOP 1: Decreasing maintenance budget (Henning Lundstrom, Vattenfall) Background An introduction was presented in three aspects from points of view of: The discussions led to a number of conclusions/headlines to be taken into account when optimizing the maintenance during financial crises - Long term planning of competences and the related outsourcing Due to differences in the organization structures the conclusions must be adapted to the company in question. The presentation can be found in the closed user group. A bid invitation was made to five service companies for some overhaul works on two small steam turbines of a waste incineration plant according to special rules "VOB". It turned out that the winning company had not enough personnel to handle the job. No responsible man on site, no commissioning engineer. The presentation can be found in the closed user group. Generator failures usually cause a long period of unavailability.
The presentation can be found in the closed user group. More than 80 % of the cost of maintenance is spent in big projects (General Overhaul, repair or exchange of major parts of power units etc.). Reengineering of process preparing and executing of the projects can bring significant reduction of the cost. CEZ applied methodology "Design to Cost" on ten pilot projects in the area of maintenance last year. Using multidisciplinary team and involvement of the suppliers including using of preciously defined tools has brought cost savings by 30 percent. At the same time members of the team (from different departments of the company) takes more detailed knowledge how to prepare other projects which is very valuable for their future work. The presentation can be found in the closed user group. Simple queuing theory and Poisson distribution calculations can be used to assess the sufficiency, which is the probability that a spare is not present given a component failure that requires a spare. However, comparison with Monte Carlo simulation will show that such theories have their limitations. For instance, if more than 1 component in 1 power plant fails causing the plant out of operation and that component would need the spare, adding the remaining failure rates is too conservative since the remaining components are less likely to fail with the plant not running. Similarly, the number of customers waiting in queuing theory must be at maximum the number of components that call for the spare. The VGB KISSY unavailability database was used to calculate failure rates and repair times at a 3 level KKS-code. A subset of raw unanimous failure data was supplied by the VGB. KEMA estimated that the free text would allow to sufficiently pinpointing components within that 3 letter KKS system code. However, this was only partly possible since the data quality and the amount of free text differs much between plants. Engineering judgment was applied to check if a spare part would be applicable based on the text and the repair time. Apart from instrumentation, spare parts were thought to be only applicable beyond a certain repair time (f.i. 24 hrs). Engineering judgment is certainly necessary to arrive at the estimates from the data. To conclude: the 3 types of analysis show different views but are supportive in reaching conclusions with regard to optimum spares. Simulation provides the best guidance and understanding. The availability of documented failure data together with the use of spares to solve the failure is a limiting factor that has to be supplemented with engineering judgment. The presentation can be found in the closed user group. For several years EDF R&D has been developing a probabilistic methodology to optimize the lifecycle management of a given SSC (System, Structure or Component), i.e to help answer the following question : which investments have to be done, and when, to ensure a sufficient level of security, availability and performance of the SSC ? That methodology consists of 3 main steps :
This methodology has been used for several years to help EDF's generation and engineering Divisions to make the proper investment decisions to optimize the life cycle management of their power plants and this presentation describes how it has been applied to the reheater of a 600 MWe coal-fired power plant. The presentation can be found in the closed user group. In a tough economic climate when there are powerful pressures to reduce expenditure on asset management, it is important to ensure that the control of major process safety risks remains a clear priority. Process safety risks are the result of upsets and failures in the power generation plant as opposed to hazards arising from work activities. Process safety incidents can be defined as uncontrolled releases of energy or hazardous substances with the potential to cause harm to people or the environment. To control process safety risks successfully, it is first necessary to identify the relevant plant related hazards. For conventional power plant, these hazards typically include release of steam or other hot materials, explosions, projectiles, electrical blast, structural collapse or harmful spills. Individual process safety hazard scenarios for specific equipment can be identified using check lists, HAZID or HAZOP studies. Having identified specific hazard scenarios with their causes and consequences, it is then necessary to identify the barriers that are used to help prevent the incident and limit the resulting harm. These barriers can be shown graphically using a bow tie diagram. Barriers include standards, operating procedures and operator training, automatic protection systems, inspection and testing, leak detection, fire fighting and emergency procedures. Effective process safety risk management requires that barriers are well known, they are sufficiently effective, they are known to be working and they are improved with experienced. The presentation can be found in the closed user group. TOP 8: Condition Based Maintenance (Nicky Codd, ESB) ESB Generation Operations carried out a study of current Condition Based Maintenance, (CBM), practices in the Power Industry. It examined ESB Generation Operations practices against the best practices in the Industry. Whilst the report concentrated on CBM, other maintenance approaches were also explored. It is acknowledged that CBM is not an overarching maintenance strategy; rather it is a technique which can be effectively employed in the overall maintenance strategy with good results. CBM has been employed in Generation Operations for many years. Its application is more effectively utilised in some areas such as Generators and Turbines. CBM technologies are utilised broadly in Generation Operations, however our findings show that we are not always taking full advantage of the technique..... The presentation can be found in the closed user group. The Benchmarking process employed by ESB has assumed greater significance as the company competes in a commercial electricity market. The process gives important information on both plant and component reliability and the relative cost of maintenance against peer group units. The recent round of benchmarking has initiated a number of performance improvement projects, such as mill performance improvement and trips reductions. At the heart of these projects is the delivery of improved ESB have decided to expand their benchmarking process to include Hydro and Gas fired plant the outputs of this process will feed into the 2012 budget cycle and performance improvement projects. Whilst it is acknowledged that benchmarking is time consuming the identification of performance gaps with peer groups is an important business planning tool. The presentation can be found in the closed user group. The next meeting will be held on 6./7. October 2011 in Paris.
|
Member-Login |