Power modulation of Sidney HVDC scheme. II. Computer simulation

For pt.I see ibid., vol.7, no.4, p.2145 (1989). The back-to-back Sidney (Nebraska) Converter Station (SCS) provides an asynchronous 200 MW tie between the east and west AC power systems of the United States. The addition of the SCS to the network required a remedial action scheme (RAS) integrated in the HVDC (high-voltage direct-current) control in order to meet AC systems reliability criteria. One of the basic components of the RAS is the frequency-dependent power modulation combined with an effective voltage control in the western network. Computer simulations were performed to check design and to provide initial settings for the RAS. As one part of the commissioning of the SCS, field tests of the RAS were conducted. The digital calculations were found to agree very well with the field test results. The simulation study covered two extensive AC networks with generators, their excitation control and speed-governing system representation, an HVDC with its standard controls, and the additional RAS for modulation and ramping of the power transferred