Abstract This paper proposes an operational reliability assessment approach of photovoltaic (PV) inverters considering a voltage/VAR control (VVC) function. The approach aims to quantify the reliability degradation and estimate the lifetime of PV inverters when they are utilized for the VVC function. Firstly, an inverter based VVC model considering uncertain profiles of PV power generation and loads is developed and it is solved by a stochastic optimization method. Then, a long-term reliability assessment procedure of the inverters utilized in the VVC model is proposed. To assess the reliability, a power loss model considering the VVC results is developed and a modified lifetime model based on Coffin-Manson model and manufacturing information is proposed. The proposed VVC model and inverter reliability assessment approach are verified on a 33-bus distribution network. The simulation results reveal the long-term impacts of additional utilization in the VVC function on operational reliability and lifetime of PV inverters.

中文翻译：

---

考虑电压/无功控制功能的光伏逆变器运行可靠性评估

摘要 本文提出了一种考虑电压/无功控制（VVC）功能的光伏（PV）逆变器运行可靠性评估方法。该方法旨在量化可靠性退化并估计光伏逆变器用于 VVC 功能时的寿命。首先，开发了一种考虑光伏发电和负载不确定性的基于逆变器的 VVC 模型，并通过随机优化方法对其进行求解。然后，提出了 VVC 模型中使用的逆变器的长期可靠性评估程序。为了评估可靠性，开发了考虑 VVC 结果的功率损耗模型，并提出了基于 Coffin-Manson 模型和制造信息的改进寿命模型。所提出的 VVC 模型和逆变器可靠性评估方法在 33 母线配电网络上得到验证。仿真结果揭示了额外利用 VVC 功能对光伏逆变器的运行可靠性和寿命的长期影响。