Internal Fault Analysis and Optimization Design of Main Protection Scheme for Large Condenser

摘要

Large condenser (300Mvar) has the possibility of inter-turn short-circuit in stator windings. Absence of protection against inter-turn short-circuit will be a serious threat for the safe operation of the condenser. Using the Multi-Loop analysis method, internal fault analysis and optimization design of main protection scheme are carried out for two kinds of condenser with different cooling modes. The analysis shows that different main protection schemes should be selected according to the difference in the number of branches per phase of the large condenser. Compared with the main protection scheme based on traditional electromagnetic current transformer, the complete or incomplete split phase transverse differential protection based on flexible optical current transformer will completely solve the problem of imperfect stator winding inter-turn short-circuit protection for large turbo-generator. And the new scheme has very small influence on the generator design and manufacture, thus guaranteeing the safe operation of generators.