WORLD PULP&PAPER 33 Figure 2. OEE model, in the context of plant electrical equipment. There is a need to manage electrical system reliability and availability for the lifecycle of plant shutdown, providing a window to prepare and carry out other urgent maintenance actions in the pulp mill. The pulp mill electrical power distribution system starts with the connection to the high voltage power grid and continues with the mill’s internal medium voltage power distribution network that feeds different parts of the mill. The steam turbine generator feeds power to the mill high voltage power grid. All of the electrical equipment has failure modes that represent a risk to availability of production. High and medium voltage disturbances could cause large section stoppages or complete mill shut down, and low voltage equipment could cause process disturbances in their related department. Redundancy can be built in for many critical applications, but most of the equipment could potentially cause an unplanned shutdown. There is a need to manage electrical system reliability and availability for the lifecycle of plant. This drives certain operational needs: • Tools to monitor single pieces of equipment, as well as the whole system’s equipment reliability and availability • Early identification of warning signals, which typically indicate impending failures • Decision support for how to prioritise maintenance and shutdown activities • Estimate equipment remaining lifetime and define the right time to replace it • Reduce time needed for troubleshooting in failure situations increased by reducing troubleshooting and repair times by having all relevant information immediately available, and by having backup support from supplier specialists. Performance – can be positively impacted by detecting possible bottlenecks and performance issues from equipment data. Quality – can be improved by cooperative efforts toward process optimisation by using precision measurement from the electrical equipment, for example high-resolution measurements from the drive system. EQUIPMENT MONITORING In a pulp mill, the usage of individual equipment varies according to the process area, applications and production volume. Knowing how equipment has been used and in which environmental conditions are key to making smart maintenance decisions that will improve OEE. Collecting all needed data and transforming it into useful information for maintenance • Validation of original design and operational parameters during production ramp-up phase OVERALL EQUIPMENT EFFECTIVENESS IS A COMMON WAY TO MEASURE PRODUCTIVITY To measure any industrial plant performance, Overall Equipment Effectiveness (OEE) is typically used. OEE is the result of three factors which form one indicator to measure total effectiveness. OEE = A × P × Q Availability – is reduced by equipment failure, setup and adjustment. Performance – is reduced by idling and lower speed. Quality – is reduced by process defects and startup losses. Improvements in OEE can be made by enhancing one or more of the three contributing areas: Availability – can be improved by avoiding unplanned downtime caused by failures, by detecting them before they occur. Availability can also be