摘要
针对直驱永磁同步机组(PMSG)协同感应风电机组(IG)低电压穿越(LVRT)问题,提出PMSG最少台数的定量算法。根据转矩平衡关系,计算IG滑差失稳的临界转差率。根据临界转差率和故障持续时间,对转矩平衡方程积分,得到IG不失稳时公共连接点临界电压。根据并网导则的最严重电压跌落,推导协助IG LVRT所需无功和PMSG最少台数。给出动态仿真结果以验证协同LVRT效果,量化了理论推导误差。发现IG惯性时间常数或转子电阻越大,机械转矩或定子电抗越小,故障时间越短,临界电压越低,PMSG越容易协助IG LVRT;对临界电压影响从大到小依次为IG机械转矩、故障时间、IG转子电阻、IG惯性时间常数和定子电抗。
An algorithm is proposed to figure out the minimum sets of direct-driven PMSG（Permanent-Magnet Synchronous Generator） required for the coordinated LVRT（Low- Voltage Ride- Through） of IG（Induction Generator） and PMSG. The critical slip for yielding IG instability is calculated according to the torque balance relation and the integration of the torque balance equation according to the critical slip and the fault duration is carried out to obtain the critical voltage of PCC（Point of Common Coupling） for maintaining IG stability. According to the severest voltage drop stipulated in the grid code,the required reactive power and the minimum sets of PMSG for the coordinated LVRT of IG and PMSG are derived. The dynamic simulation is performed to validate the effect of coordinated LVRT and quantify the error of theoretical derivation. It is found that,larger IG inertia time constant,larger IG rotor resistance,less IG mechanical torque,less IG stator reactance or shorter fault duration yields lower critical voltage,resulting in easier coordinated LVRT of IG and PMSG. The influence of following factors on the critical voltage is sorted from bigger to smaller：IG mechanical torque,fault duration,IG rotor resistance,IG inertia time constant,IG stator reactance.
出处
《电力自动化设备》
EI
CSCD
北大核心
2015年第2期21-27,共7页
Electric Power Automation Equipment
基金
国家自然科学基金资助项目(51277049)~~
关键词
风电场
低电压穿越
感应发电机
直驱永磁同步发电机
临界电压
wind farms
low-voltage ride-through
induction generator
direct-driven permanent-magnet synchronous generator
critical voltage
