METHOD AND ARRANGEMENT FOR PROTECTING TURBINE GENERATORS AGAINST SUBSYNCHRONOUS RESONANCES OCCURING IN POWER TRANSMISSION SYSTEMS

摘要

Abstract of the disclosure:This invention relates to a method by means of which aturbine generator can be protected against sub-synchronous frequencies occurring in an electric networkwhich is connected to the turbine generator and which in-corporates capacitors. The method is based on de-equal-izing the subsynchronous natural frequencies of the threephases, so as to weaken the coherence of the frequencies.This is achieved by incorporating in each of two of thephases a respective inductance L of mutually different sizeand by changing the capacitance equivalently with a seriescapacitance C such as to fulfill the condition 1/LC = .omega.?,where .omega.o is the network frequency.