The paper analyses the electromagnetic processes during emergency situ
ations in a thyristor frequency converter (TFC) with an intermediate d
.c. link, Relationships of emergency currents are also analysed, takin
g into account overload protection. Emergency current relationships ar
e obtained in analytical form, making it possible to evaluate their ac
tion on the thyristor valves and other equipment of the TFC, and to ch
oose an electrical strength reserve and design an optimum algorithm fo
r overload protection system operation. (C) 1997 Elsevier Science Ltd.
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