Implementation of electrode boilers for frequency control of utility grids

Abstract

This thesis successfully demonstrates an algorithm for improving the power control of a high-voltage electrode boiler being utilized for load-frequency control, by actively adjusting the slopes of XY-curves used for boiler water level control set-point and outputs as a function of boiler temperature.

The increase in transient energy co-generation, such as wind-power, places greater demands on an electrical grid for maintaining load-frequency control. A common method for load-frequency control used in Europe is decentralized co-generation plants with high-voltage electrode boilers. These provide a secondary benefit of hot water district consumer use.

Current high-voltage electrode boilers used for load-frequency control do not account for water temperature when determining conductivity and water-level set-points. Set-point curves are determined at the time of commissioning and then set. This thesis develops and tests an algorithm that accounts for boiler water temperature and dynamically adjusts the XY-curves that define the system behavior. The tested algorithm showed a clear improvement in maintaining load-frequency control, reducing the mean power error to O ± 0.5%.