Back corona detection and current setback for electrostatic precipitators
AssigneeNWL Transformers
InventorThomas C. Laugesen
Life of this patent
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Abstract
A back corona detector that reduces current flow to the plates of an electrostatic precipitator when a corona occurs between a plate and the dust layer that forms on the plate thereby minimizing the corona condition. The ramping voltage in a transformer/rectifier set under usual operating conditions will vary proportionally with current flow. At the onset of a back corona condition, a comparator senses a sudden increase in current with respect to the voltage indicating that the current is being consumed to maintain the corona rather than providing for particulate precipitation. A current set-back circuit is then pulsed periodically so that the current is continuously reduced until the voltage/current relationship is maintained at the knee of the voltage/current curve.
Claims6
A control system for monitoring across an electrostatic precipitator the departure of current from voltage at the start of a back corona condition and continuously reducing the current until said back corona condition is substantially minimized comprising
- means for comparing the voltage and current applied to the precipitator for detecting when said current increases at a faster rate than said voltage for producing a signal indicating a back corona condition, and
- means for setting back said current in response to said back corona condition signal for substantially minimizing said current while maximizing said voltage to maintain normal precipitator operation at the knee of the voltage/current curve.
Dependencies are inferred from the claim text.