Asynchronous Thyristor By-Pass Increasing Short Circuit Capability of the Variable Speed Generating Set

摘要

The paper describes an adjustable speed generation system producing three phase sinusoidal voltage in wide speed range. The generation system provides high quality voltage, delivered by a DC/AC transistor converter, and has short circuit current protection by conventional circuit breaker class B. The quick tripping of the circuit breaker requires high amplitude current. This ability, to produce high short circuit current, is assured by thyristor by-pass. The thyristor by-pass connects directly windings of the permanent magnet generator and the output. As the generator voltage frequency is higher than AC output voltage then deactivation of thyristor by-pass is easy. Paper presents topology of the by-pass and results of laboratory tests of a 40kVA generation system in cases of different speeds.