Rule-Based Energy Management System Applied to Large Industrial Facilities

Abstract

Deregulation of electricity and rising fuel costs are causing renewed interest in Energy Management Systems (EMS). This paper details the results of integrating a rule-based EMS controller at a Pulp and Paper Mill and additional findings from several other large industrial power complexes. It is a PC-based supervisory system that is interfaced to a Distributed Control System (DCS). The EMS has been applied on powerhouse complexes as large as 433 MW of electricity and 7500 KPPH of steam. The EMS may, as required, include boiler load allocation, steam turbine load allocation, combustion turbine and HRSG load allocation, real-time pricing (RTP) tie-line control, coordinated header pressure control, bus voltage and plant power factor control and electric and steam economic load shed systems. It optimizes the powerhouse operations to meet rapidly changing steam and electrical requirements of the plant at minimum cost subject to all of the operating constraints imposed on the generation equipment. Steady state optimization methods, such as linear and non-linear programming, are not suited for on line optimization of power complex operations since the process is rarely in steady state. Instead, it is critical to control the trajectory of the power generation for optimal steam and electric moves while satisfying multiple constraints. The optimization strategy applied here is reduced to a fairly small number of prioritized rules. It has proven itself capable of optimizing large powerhouse complexes while keeping the powerhouse and process units within a safe operating envelop.