Generator-Circuit Breakers for Nuclear Power Plants

A comparative analysis of the characteristics of foreign and domestic generator circuit breakers is carried out. The necessity of developing a domestic generator circuit breaker for newly constructed nuclear power plants with a power unit capacity of over 1200 MW is shown. The most promising solution is the development of hybrid generator circuit breakers using main contacts, vacuum circuit breakers and controlled arresters. The scheme and operation of elements of hybrid circuit breakers in modes of shutdown of three
phase short
circuit current is resulted. The developed mathematical model of hybrid breakers consisting of generator, busbar and transformer for power plant and given transients disable the short
circuit current in different modes. It is proposed to develop hybrid circuit breakers to replace oil and air circuit breakers at the stages of modernization of nuclear power plants, and in the new construction it is advisable to use generator circuit breakers, as a prototype of which the gas-insulated device developed by ABB is given. Basic electrical formulas for estimation of the switching capacity of the circuit breaker of the generator in the amplitude of the current gap three
phase short
circuit current, degree of asymmetry, amplitude and rate of rise of transient recovery voltage formulated.