The Influence of Reactive Power Control on the Turbine Generator Operational Reliability

Abstract

The need to operate turbine generators in the reactive power absorption mode is stemming from a shortage of compensation devices in the grid. The operation of a conventional turbine generator as a reactive power compensator sometimes entails undesirable consequences for it. Recent years have seen a growing number of generator failures related to their prolonged operation at low excitation levels, which is the necessary condition for the generator to absorb reactive power. The article briefly describes the main factors that determine the relevance of the problem of reactive power control in the Moscow Region power system and the need to shift turbine generators for operation in the reactive power absorption mode. The article also provides information on the influence of operating modes in terms of reactive power control on the technical condition of the power plant main electrical equipment. The study is aimed at assessing the influence of reactive power control on the reliability of turbine generators. Based on a retrospective analysis of information on the technical condition of turbine generators and information about their damageability, recommendations on the possibility of using turbine generators for operation in reactive power absorption modes are drawn up. The operation of turbine generators in under-excitation modes eventually entails, regardless of their type and capacity, deterioration of the technical condition of the teeth of stator core end packages. In the absence of proper monitoring, fragments of crumbled sheets of active steel can cut through the stator winding case insulation, and the risk of its breakdown during operation or testing will increase. Under these circumstances, it is not possible to guarantee their reliable long-term operation.