Subsynchronous Torsional Interaction of Wind Farms with FSIG Wind Turbines Connected to LCC-HVDC Lines

Abstract

Abstract:High-voltage direct current (HVDC) lines with line-commutated converter (LCC) are being increasingly employed to transmit bulk wind power over long distance. However, this may cause the sub-synchronous torsional interaction (SSTI) between the wind farms and the LCC-HVDC system. The SSTI characteristics of wind farms with fixed-speed induction generator (FSIG) wind turbines connected to LCC-HVDC are investigated in this paper. To simplify the calculations, a modular modeling method is proposed for building the small-signal mathematical model of the investigated system. Small-signal analysis, participation factor analysis, and impact of dominant factors analysis are then applied to investigate the SSTI characteristics under different operating conditions. Three oscillation modes associated with the SSTI are identified in the entire system through small-signal and participation factor analysis, comprising two torsional modes and an electromechanical mode. Impact of dominant factors analysis shows that the system becomes less stable as the wind farm capacity grows and the distance between FSIG wind farm and the rectifier station increases. Moreover, the above analysis suggests that wind farms with FSIG connected to LCC-HVDC lines may not cause unstable SSTI. The electromagnetic transient simulations based on PSCAD/EMTDC (Power Systems Computer-Aided Design/Electromagnetic Transients including DC) verify these results.

Electrical Damping Assessment and Stability Considerations for a Highly Electrified Liquefied Natural Gas Plant

“…Energies 2020, 13, 2612 9 of 27 From Equations (3), (6), (8), (10) and (12), it is possible to define i DC and i DC as a function of the initial conditions and of the external inputs:…”

“…Limited literature has been published about SSTI phenomena in LNG plants [5][6][7][8]. Differently, numerous studies can be found on SSTI for High Voltage Direct Current (HVDC) applications [9][10][11][12][13]. In this context, SSTI is categorized as the evolution of the Sub-Synchronous Resonance (SSR) phenomenon [14][15][16][17][18].…”

Transient Faults in Wind Energy Conversion Systems: Analysis, Modelling Methodologies and Remedies

“…The change in topology triggered by equipment switching events causes transient faults induced by short circuit current, which consequently establishes resonant conditions in a power plant. However, wind farms that employ fixed speed induction generator (FSIG) coupled to HVDC lines and are equipped with line-commutated converters are quickly becoming popular in the transmission of large amounts of electrical power over long distances with significant reductions in transient instabilities, especially due to sub-synchronous torsional interaction [71,72]. Recently, a novel technique for detecting several DC fault conditions in a multi-terminal VSC-HVDC scheme was devised in [73] with the use of transient overvoltage with respect to the cable sheath.…”

Research on the Inductance/Capacitance Switch Model for an LCC-HVDC Converter in an AC/DC Hybrid Grid

“…The equivalent circuits are shown in Figures 3 and 4, and the circuit equation is shown in Equation (2). i d can be seen as direct current:…”

“…In an AC/DC hybrid grid, the interaction between AC and DC and mutual influences between sending and receiving ends changes the system characteristics significantly. Line commutated converter HVDC (LCC-HVDC) has high level of voltage and large transmission capacity and it is the main component of AC/DC power network [1,2].…”