Design & implementation of an industrial facility islanding and load shed system

The availability of electricity supply in all areas of life has become a critical need. In the industrial arena, costs due to the loss of electrical power and resulting process interruption can usually be quantified into hard dollars. Many larger industrials, however, contain significant co-generation capability that produce both electricity and waste heat for steam production utilized in the plant processes. At any instant in time, the available generation may be able to supply the needs of the plant if islanded; at other times and conditions, a sizable portion of the plant load must be shed in order for the load to match the available generation. In all cases, the goal is to maintain as much of the plant process as possible during an external disturbance or island condition in order to minimize environmental impact, production loss, and potential equipment damage. This paper presents the design and implementation details of a control system that detects an island condition in an industrial facility, creates the island if needed, and executes a multi-tier load shed based on the load-generation balance that existed prior to the creation of the island. System operation in island mode and performance metrics obtained from dynamic tests are presented.