Requirements for the Excitation System in the Development of Units and Grid Coordination

The concept of Units and Grid Coordination (UGC) is introduced. Problems about UGC are drawn from some power interruptions. Some attentive issues are present in excitation selection and design in future power system such as reliable operation of PSS, coordination between excitation limiters and protections, operation mode of excitation control in running stage. Special attention should be paid to the selection of excitation type, parameters design of 1000MW class generator unit in planning stage.