MGP提高光伏发电系统高电压穿越能力的研究

Study on Motor-Generator Pair for Improving High Voltage Ride-through Capability of Photovoltaic Generation System

随着新能源接入电网的比例越来越高,新能源电场面临的暂态过电压问题越来越严重,而新能源机组普遍暂态过电压耐受能力较低,因此提高新能源机组的高电压穿越能力十分重要。同步电机对系统(Motor-Generator Pair,MGP)具有良好的电压隔离和无功支撑特性,因此可以提高新能源的高电压穿越能力。本文首先结合MGP系统的数学模型分析了其功角特性和功率控制方法,随后分析了MGP发挥电压隔离保护作用的机理。针对光伏通过MGP并网的控制方式,通过仿真分析了该控制方式下MGP在光伏发电系统高电压穿越过程中的电压支撑效果,然后通过实验验证光伏通过MGP并网可以在1.3p.u.过电压持续5s的工况下实现高电压穿越。证明MGP系统可以有效地提高光伏发电设备的高电压穿越能力,且均高于现行的国家标准。

With the increasing proportion of renewable energy connected to power grid,transient high voltage problem in renewable power plant is becoming more and more serious.However,renewable energy units generally have poor transient high voltage withstand capability.So improving the high voltage ride-through capability of renewable energy units is of significance.The motor-generator pair(MGP)system performs well on voltage isolation and reactive power support to improve ride-through capability of renewable energy.In this paper,power angle characteristics and power control method are analyzed firstly with the mathematical model of MGP,and then the mechanism of voltage isolation protection by MGP is analyzed.For the control method of PV grid-connection via MGP,the effects of the voltage support during the high voltage ride-through is analyzed through the simulation proposed based on power angle characteristics of MGP.Then,the experiment results prove that the PV grid-connection via MGP can realize high voltage ride-through for 5s at 1.3 p.u.high voltage conditions.The results also prove that MGP system can effectively improve the high voltage ride-through capability of PV generation system,and the results are higher than current national standards.