Enhanced Voltage Regualation Method in Wind Power Grid-Connected Systems Through Cooperation Control of Hybrid Transformer with Wind Farm for Minimal Compensation Capacity Requirements

As the proportion of renewable energy power generation integrated into the grid continues to rise, the voltage stability at the point of common coupling (PCC) is facing challenges. The stochastic and fluctuating characteristics of wind power generation can lead to voltage fluctuations and overruns, influencing the safe and stable operation of the power system. It is urgent to propose a method to enhance the node voltage management capability at the PCC. Combined partially rated capacity converters and electromagnetic transformers, hybrid transformers (HTs) are considered a promising voltage regulation equipment with high efficiency and reliability. This paper presents an enhanced voltage regulation method in wind power grid-connected system through cooperative voltage compensation from both HT and wind farms to achieve the minimal compensation capacity requirements of hybrid transformers. By analyzing the working principle of HT, a mathematical model and control strategy of cooperative voltage compensation are established. A wind power grid-connected model was constructed in PSCAD, and the simulation results verified the feasibility and effectiveness of the proposed strategy. The proposed strategy successfully compensates voltage sag at the PCC, fully utilizing the reactive power compensation capability of the wind turbine generations (WTGs). It reduces the total capacity requirement of the HT converters by about
$45{{\% }}$
for the same compensation need.