Determination of negative-sequence resistance of turbo-generators from rated-frequency standstill tests

摘要

Systematic analysis and comparison of standstill and rotational test results for a large number of turbogenerators in the range of 30 to 1300 MVA and having various damper systems, shows that the ratio of negative-sequence resistance to mean subtransient resistance varies in a narrow range of +or-10% around 0.85. This corresponds to an increase of about 1.5 to 1.85 times in the equivalent rotor resistance when the frequency is doubled, in contrast to the figure of square root 2 quoted in literature. Additional verification is obtained from frequency-response tests on one of the machines investigated.