In recent years, accelerated climate-change mitigation efforts and energy
transition policies worldwide have driven a rapid expansion of renewable energy
deployment, particularly solar and wind power. Among these, wind generation has
experienced a m...
In recent years, accelerated climate-change mitigation efforts and energy
transition policies worldwide have driven a rapid expansion of renewable energy
deployment, particularly solar and wind power. Among these, wind generation has
experienced a marked upscaling in unit capacity enabled by technological
advancements, and its role as a major electricity supply resource continues to
grow. As policy-driven demands to replace fossil-fuel-based generation and
reduce greenhouse-gas emissions intensify, the penetration of wind turbines in
power systems is expected to increase further.
However, wind turbines are predominantly connected to the grid through
power-electronic converters, which can reduce frequency stability and overall
system robustness compared with conventional synchronous-generator
dominated systems. This challenge is largely attributed to the limited inherent
inertia of converter-interfaced generation, which can prolong low-voltage
conditions following voltage disturbances and delay the recovery of active power
and system frequency. To address these issues, many countries have established
grid codes that specify minimum technical requirements for the interconnection
and continued operation of renewable energy resources. Nevertheless, because
interconnection requirements have been developed and updated rapidly in
response to the swift increase in renewable penetration, inconsistencies and
stakeholder conflicts may arise. In particular, applying uniform criteria to modern,
increasingly large wind turbines may result in inadequate active-power recovery
performance or failure to restore frequency to nominal values, potentially leading
to non-compliance and disconnection. Accordingly, there is a growing need to
develop differentiated active-power recovery requirements that explicitly account
for turbine rated power and drivetrain shaft length, reflecting the characteristics
of large-scale wind turbines and wind power plants.
In this study, torsional vibration phenomena in grid-connected wind turbine
systems are investigated. The wind-turbine drivetrain is modeled using a multi
mass representation, and the relationship between the inertia constants of the
lumped masses and the shaft stiffness parameters is examined. Furthermore, the
scaling characteristics of turbine parameters with respect to rated capacity and
shaft length are analyzed to propose active-power recovery characteristics that
are suitable for upscaled wind turbines. The proposed model is implemented using
PSCAD/EMTDC, and the validity of the simulation results is verified through
Python-based post-processing and analysis.