Power links with Ireland -- Excitation of turbine-generator shaft torsional vibrations by variable frequency currents superimposed on DC currents in asynchronous HVDC links

Journal Article · Tue Aug 01 04:00:00 EDT 1995 · IEEE Transactions on Power Systems

DOI:https://doi.org/10.1109/59.466486· OSTI ID:163059

Hammons, T J; Tay, B W; Kok, K L ^[1]

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1. Glasgow Univ. (United Kingdom)

The paper describes an in-depth analysis of excitation of shaft torsional vibrations in steam-turbine-generator-exciter shafts in close proximity to HVDC converter stations by variable-frequency ripple currents superimposed on the DC currents in asynchronous Links. It extends earlier work to include an in depth analysis of system scaling factors for harmonic currents impressed on generators in Northern Ireland by an inverter and to investigate the phenomena for possible torsional vibrations in the generators by the Link. Frequencies at which shaft torsional vibrations would be excited by modulation product harmonics in 50Hz/50Hz asynchronous Links as a function of deviation in system frequency is reviewed. Relative noncharacteristic current levels for 50Hz/50Hz connectors are illustrated assuming ripple currents at the inverter which gives realistic harmonic voltages in a twelve-pulse bridge. The paper then shows that torques in machines in multi-machine networks may be estimated by proportioning HVDC link harmonic disturbance current appropriately to each machine at risk. It is concluded that variable-frequency ripple currents superimposed on the DC current in asynchronous links can excite sympathetic torsional vibrations in turbine-generator-exciter shafts.

• OSTI ID: 163059
• Report Number(s): CONF-950103--
• Journal Information: IEEE Transactions on Power Systems, Journal Name: IEEE Transactions on Power Systems Journal Issue: 3 Vol. 10; ISSN ITPSEG; ISSN 0885-8950
• Country of Publication: United States
• Language: English

Related Subjects

24 POWER TRANSMISSION AND DISTRIBUTION
HVDC SYSTEMS
INTERCONNECTED POWER SYSTEMS
IRELAND
MECHANICAL VIBRATIONS
TURBOGENERATORS