Evaluation of Reactive Power Reserves in Transmission Systems

Abstract The paper deals with system problems of reactive power reserve conditions. Reliability level and security criteria in system planning and operation are discussed in relation to the allocation of reactive power reserves in the network. Alternative criteria of reactive power reserves are specified. Sensitivity methods to calculate system responses and network conditions are described. Evaluation of different criteria is carried out on a network exercise, where large disturbance tests are used to investigate the network performance during increased reactive power demand conditions.