光伏阵列I-V特性曲线测量误差分析与修正方法

MEASUREMENT ERROR ANALYSIS AND CORRECTION FOR I-V CHARACTERISTIC OF PHOTOVOLTAIC ARRAY

光伏电站内光伏阵列的现场I-V测量可以评估当前系统发电性能和阵列状态,但现场的传输线路阻抗会使I-V测量产生误差,影响了评估的准确性,不利于光伏电站运维决策。该文分析测量线路阻抗和环境参数对常规动态电容I-V测量方法的影响机理,并进行仿真验证。根据误差影响机理和测量回路等效模型,提出一种双电容组合I-V特性测量方法,并研制样机进行实验验证。实验结果表明,该测量方法可有效消除线路分布参数对光伏阵列I-V测量的影响,提高测量精度。

The on-site I-V measurement of photovoltaic array in a photovoltaic power station can evaluate the current system power generation performance and array status,but the on-site transmission line impedance will cause error in I-V measurement,which not only affects the accuracy of the estimate but also is not beneficial to the policy-making of the photovoltaic power station operation.The article analyzes the influence mechanism of measurement line impedance and environmental parameters on the conventional dynamic capacitance I-V measurement method,and conducts simulation verification.According to the influence mechanism of the error and the equivalent model of the measurement loop,the article proposes a method for measuring the I-V characteristics of a dual-capacitor combination,and develops a prototype for experimental verification.The experimental results indicate that the measurement method can efficaciously eliminate the influence on I-V measurement of photovoltaic array by line distribution parameters and improve the measurement accuracy.