基于湿热试验的光伏组件功率衰减与使用寿命研究

Study on power degradation and service lifetime of photovoltaic modules based on damp-heat test

摘要:

光伏组件功率衰减与使用寿命对于光伏电厂安全、经济运行具有重要意义。针对光伏组件功率衰减和使用寿命问题,在分析加速湿热条件下光伏组件归一化功率倒S形衰减规律基础上,提出以指数时间尺度变换函数对光伏组件非线性归一化功率进行变换,并运用Gamma过程对加速湿热条件下光伏组件归一化功率衰减数据进行建模,进而根据光伏组件使用寿命定义估计光伏组件使用寿命。通过加速湿热试验下光伏组件实测使用寿命与估计的使用寿命,验证了所提方法的正确性与合理性。方法表明,在50℃、45%相对湿度条件下光伏组件平均寿命近似为20~25年。与此同时,还对现有的加速退化试验进行了分析改进,探讨了运用步降加速退化试验代替传统的恒定应力加速退化试验的可能性。

Abstract:

Aiming at the problem of power degradation and service lifetime of photovoltaic (PV) modules, based on the inverted S-shaped normalized power degradation law of PV modules under accelerated damp-heat conditions, an exponential time scale transformation function is proposed to transform the nonlinear normalized power of PV modules. The Gamma process is applied to model the normalized power degradation data of PV modules under accelerated damp-heat conditions, and service lifetime of PV modules is estimated based on the definition of PV module lifetime. The correctness and rationality of the proposed method are verified by measured service lifetime and estimated service lifetime of PV modules under the damp-heat test. The method shows that the average service lifetime of PV modules is about 20-25 years at 50 °C and 45% relative humidity. At the same time, the existing accelerated degradation test was analyzed and improved, and the possibility of using the step-down accelerated degradation test instead of the traditional constant stress accelerated degradation test was discussed.