Fuzzy logic-based power control system for multi field electrostatic precipitators

The power consumption of large precipitators can be in the range of one MW and above. Depending on the dust load properties, the electrical power may be reduced by up to 50% by applying fuzzy logic, without significantly increasing the dust emissions. The new approach using fuzzy logic is an optimisation of the existing precipitator. Software running on a standard personal computer platform under Windows NT facilitates the reduction in power usage. The controllers of the electrostatic precipitator power supplies are linked to the computer via an industrial network (e.g. PROFIBUS). The system determines online the differentials of emission versus electrical power of each field. This measurement is difficult because of overlaid events in the other zones, and process changes. The long response time of the resultant dust emission due to electrical power changes in the precipitator is an additional complication. Rules were defined for a coarse, but fast response power adaptation of all zones. Fine tuning the running system after the coarse optimization increased the accuracy and reliability. When installed on a 4 by 5 zone precipitator in a power station meaningful results can be obtained. The power savings over 3 months of operation were 40% to 60% depending on the load and fuel characteristics. Data was recorded over the test period of 3 months. The results are presented.