Distributed solar plants are widely used in the power supply of the factories and the residences. To increase the power generation, it is inevitable to model the efficiency of the distributed solar plant and diagnose its efficiency performance. In this paper, a practical 3 MW distributed solar plant is taken as an example. The data analysis reveals the performance ratio (PR) of the plant is around 59%, which is much lower than the recommend value 75%. The efficiency diagnosis also shows that the conventional design method, which is used to determine the module quantity in a photovoltaic (PV) array, has its limitation. This method may lead to the voltage mismatch between the desired operation point of the PV array and the connected inverter, which degrades the performance of maximum power point tracking (MPPT) of the PV system. In the conventional design, the tilted angle of the PV modules is chosen based on the maximum irradiation that the modules can reach. However, the maximum irradiation on PV modules does not necessarily means the maximum electricity yield. Therefore, a new design methodology that optimizes the module quantity and the tilted angle of PV modules in the solar plant is proposed in this paper. Simulation results verify the effectiveness of the proposed method.

分布式太阳能电站广泛应用于工厂和住宅的供电。为了增加发电量，必须对分布式太阳能发电厂的效率进行建模并诊断其效率性能。在本文中，以一个实用的 3 MW 分布式太阳能发电厂为例。数据分析显示，该工厂的性能比（PR）约为 59%，远低于推荐值 75%。效率诊断还表明，用于确定光伏（PV）阵列中组件数量的传统设计方法有其局限性。这种方法可能会导致光伏阵列的期望运行点与连接的逆变器之间的电压不匹配，从而降低光伏系统的最大功率点跟踪 (MPPT) 的性能。在传统设计中，光伏组件的倾斜角度是根据组件可以达到的最大辐照量来选择的。然而，对光伏组件的最大辐照并不一定意味着最大发电量。因此，本文提出了一种新的设计方法，可以优化太阳能电站中光伏组件的数量和倾斜角度。仿真结果验证了所提方法的有效性。