HVDC system control for damping of subsynthronous oscillations. Final report

Technical Report · Fri Oct 01 04:00:00 EDT 1982

OSTI ID:6737274

Piwko, R J; Larsen, E V

Field tests in 1977 at the Square Butte Project in North Dakota, revealed that HVDC transmission systems can exert a destabilizing influence on turbine-generator torsional vibrations, and resulted in a research project, to further understand this phenomenon and develop solutions. Investigation of the interaction characteristics revealed that the destabilizing influence on rotor torsionals is due primarily to the constant current or constant power control method employed in virtually all HVDC systems. Thus, the research effort was directed towards modifications of the HVDC converter's current control loop; in concept by adding a new control function, a subsynchronous damping controller (SSDC). This report presents: a method for designing an SSDC; results from SSDC performance tests performed on both digital simulation programs and an HVDC simulator; SSDC application guidelines; and a design concept of an SSDC to solve subsynchronous resonance (SSR) problems due to series-capacitor compensated ac transmission lines. It was found that the subsynchronous damping controller can eliminate any destabilizing influence due to the HVDC system, and in many cases, can provide more positive torsional damping than a conventional ac tansmission system without series capacitors. Furthermore, where higher SSDC gains can be used, it is believed that the SSDC may hae a significant beneficial impact on the fatigue loss-of-life of turbine-generator shafts resulting from ac system short circuits or equivalent transient events. It was also found that an SSDC added to a converter station will provide some damping to a series compensated system but that it probably is unrealistic to expect SSR problems to be completely eliminated that way.

• Research Organization: General Electric Co., Schenectady, NY (USA). Electric Utility Systems Engineering Dept.
• OSTI ID: 6737274
• Report Number(s): EPRI-EL-2708; ON: DE83900539
• Country of Publication: United States
• Language: English

Related Subjects

200302* -- Power Transmission & Distribution-- DC Systems-- (1989-)
24 POWER TRANSMISSION AND DISTRIBUTION
AC SYSTEMS
CONTROL SYSTEMS
DAMPING
DC SYSTEMS
DESIGN
ELECTRIC GENERATORS
ELECTRICAL EQUIPMENT
ENERGY SYSTEMS
EQUIPMENT
HVAC SYSTEMS
HVDC SYSTEMS
INTERCONNECTED POWER SYSTEMS
MECHANICAL VIBRATIONS
OSCILLATIONS
PERFORMANCE
POWER SYSTEMS
RECTIFIERS
STABILITY
TORSION
TURBOGENERATORS