The intermountain power project commissioning - Subsynchronous torsional interaction tests
- Dept. of Water and Power, Los Angeles, CA (US)
- General Electric Co., Schenectady, NY (US)
Subsyncronous torsional vibration as a result of electrochemical interaction between the HVDC controls and a turbine-generator was first discovered during the commissioning of the Square Butte Project in 1977. The level of interaction between the HVDC controls and the turbine-generator depends on several interacting factors: the characteristic torsional frequencies of the turbine-generator, the bandwidth of the HVDC controls and the relative strength of the connecting ac system. For the Intermountain Power Project (IPP), early analysis of these interacting factors indicated that there exist definite potential for subsynchronous oscillation to occur. The calculated torsional frequencies of the IPP units showed that the first mode frequency is 14.0 Hz and is within the typical bandwidth of an HVDC control which is between 10-20 Hz. The HVDC controls, therefore, can influence the torsional stability of the IPP units. Further, the IPP turbine-generators are required to operate isolated on the HVDC rectifier terminal, with no other interconnecting ac network. This ''radial'' mode of operation will result in maximum interaction between the converter station and the IPP units. It became obvious that special measure must be implemented in the design of the IPP HVDC control system to modify its typical characteristics to avoid the occurrence of the subsynchronous oscillation. This paper presents the results of the subsynchronous torsional interaction (SSTI) tests that were performed during the commissioning of the IPP Unit 1 and the HVDC Transmission system.
- OSTI ID:
- 6798510
- Journal Information:
- IEEE Trans. Power Del.; (United States), Vol. 3:4
- Country of Publication:
- United States
- Language:
- English
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