变无功电流比例系数的直驱风电并网系统电压连续穿越控制策略

Continuous Voltage Ride Through Segmentation Control Strategy for PMSG-based Wind Power Integrated Systems With Dynamic Reactive Current Scale Factor

新能源并网导则规定风电并网系统应具备电压连续穿越的能力,而现有故障穿越控制策略主要保持无功电流比例系数为定值,缺乏定量描述无功电流比例系数的依据,可能导致后续电压连锁故障与变流器过调制等问题。为解决此问题,提出一种变无功电流比例系数的电压连续穿越控制策略。该策略依据有功电流大小与无功补偿装置切入时机划分故障电压区间,并根据并网准则要求、变流器过流限制、过调制、故障前风机的运行工况以及后续电压连锁故障等约束条件,实时计算出不同故障电压下风电场动态无功电流比例系数。该方法在满足约束条件的同时能最大程度提升风电并网系统的电压主动支撑能力,确保电压连锁故障期间风电并网系统安全稳定运行。最后,在PSCAD/EMTDC软件平台建立仿真模型,验证上述分析的正确性。

The renewable energy grid code stipulates that wind power integrated system should have the capability of continuous voltage ride through,but existing fault ride through control strategies mainly keep the reactive current scale factors as fixed values and lack a basis for a quantitative description of the reactive current scale factor,which leads to problems such as voltage continuity faults and converter over-modulation.To solve this problem,this paper proposes a voltage continuous ride through control strategy with dynamic reactive current scale factor.This strategy divides the fault voltage interval based on the active current magnitude and the cut-in time of the reactive power compensation device.Dynamic reactive current scaling factors of wind farms under different fault voltages is also calculated in real time,according to the requirements of the grid code,converter overcurrent limit,over modulation,operating conditions of the wind turbine before the fault and subsequent voltage continuity faults and other constraints.The strategy can maximize the voltage active support capability of the wind power integrated system while satisfying the constraints,and ensure safe and stable operation of the wind power integrated system during voltage continuity faults.Finally,a simulation model is built in the PSCAD/EMTDC software platform to verify the correctness of the above analysis.