利用串联制动电阻提高风电场低电压穿越能力

Improvement of Low Voltage Ride-through Capability of Wind Farms by Use of Series Dynamic Braking Resistors

风电场低电压穿越能力对电力系统的稳定性有着重要影响。介绍了利用串联制动电阻在电网故障时提升风电机组端电压并吸收过剩有功功率进而提高风电场低电压穿越能力的新方法,提出了基于转速—电压动态稳定域的制动电阻投切策略,针对基于恒速风电机组的典型风电场进行了低电压穿越稳定性仿真分析。理论分析和仿真结果表明,串联制动电阻能够可观地提高风电场的低电压穿越能力,其投切策略简单有效。串联制动电阻能减轻低电压穿越对桨距控制等其他措施的依赖,可用于改进现有风电场。

The low voltage ride-through （LVRT） capability of wind farms has a great impact on the power system stability. A novel technology is proposed to improve the low voltage ride-through capability of wind farms using series dynamic braking resistor （SDBR） which can boost terminal voltage and dissipate active power. A switching scheme of SDBR is introduced based on the dynamic stability margin of speed-voltage. This paper uses a representative wind farm model based on fixed speed wind turbines to study the transient LVRT stability. Both detailed analysis and simulation results shove that SDBR can significantly improve the low voltage ride-through performance of wind farms, and the switching scheme of SDBR is simple and effective. The technology can reduee wind farm＇ s dependence on the pitch control systems and alternatives in riding through low voltage fault, and allow retrofit existing wind farms.