Commissioning of static excitation on a 600 MW cross compound generator

NEI Control Systems have been supplying excitation control systems for use on turbogenerator plant for 25 years. The early systems were based on analogue controllers combined with a three phase thyristor bridge to supply the exciter or generator field current. In response to customer requirements these systems were refined over the years to: (i) provide more features in the controller; (ii) provide larger outputs from the thyristor converter; and (iii) to achieve higher availability by means of redundancy in both the controller and the convertor. The very latest designs are based on digital techniques many of which have been developed from the Company´s established range of electro-hydraulic governors. The first part of the paper reviews some of the possible redundancy architectures and outlines how the most appropriate redundancy techniques have been chosen and applied to the various parts of the excitation system. The second part describes in detail the testing procedures and the tuning requirement to satisfy grid system objectives