Recently, the generator terminal sub-synchronous damping control (GTSDC) system supplied by NR Electric (NR) quickly identified and accurately suppressed the torsional vibration of the shafting of two 660MW units, controlled the torsional vibration amplitude within the safe range, and significantly improved the safe and stable operation level of large generator units.
GTSDC system can identify various modes of torsional vibration of the unit shafting, inject sub / super synchronous current to the generator stator winding to offset the corresponding torsional vibration frequency through the chain power electronic converter on the stator side of the unit, generate accurate electromagnetic torque to eliminate torsional vibration.
The GTSDC system
The GTSDC system can adaptively identify the modal parameters of the generator set
The GTSDC system can adaptively identify the modal parameters of the generator set and correct them in real time according to the measured speed deviation.
The pioneering technology as electrical sudden variable start, variable gain and feed forward control are used to greatly improve the sub / super synchronous current tracking performance of power electronic converter.
Torsional vibration attenuation time is shortened
When the system detects the occurrence of torsional vibration of the generator unit, it starts to play a role within 100ms and subsides rapidly within 2s, ensuring that the torsional vibration amplitude of the two units is within the safe range, without torsional vibration protection tripping and shaft fatigue accumulation.
The previous research shows that the torsional vibration attenuation time is shortened by 90% compared with that without torsional vibration suppression measures.
Fast and accurate suppression process
The fast and accurate suppression process and effect of GTSDC system meet the design expectations
The fast and accurate suppression process and effect of GTSDC system meet the design expectations, indicating that the system can effectively enhance the damping performance of turbine grid composite resonance and solve the torsional vibration problem of steam turbine generator shaft system in AC / DC hybrid complex power grid.
It has the advantages of high modal frequency resolution, accurate and reliable speed signal measurement, and super multi-modal damping capacity and extremely fast response speed. It has great engineering application value.
Rapid start-up and precise suppression of the system
The rapid start-up and precise suppression of the system reflect the technical strength of NR in the treatment of sub synchronous oscillation of power system and torsional vibration of steam turbine generator unit.
It is also a major practice to realize ‘creating value and serving the society’ through technological innovation.
