Mitigation of Clipping Variability on Bifacial Performance Ratio of Photovoltaic Systems

减缓光伏系统双面性能比的剪切变异性

• 批准号: 10039713
• 金额: $ 1.41万
• 依托单位: STATKRAFT UK LTD
• 依托单位国家: 英国
• 项目类别: Collaborative R&D
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=10039713
• 关键词: Mitigation; Clipping; Variability; Bifacial; Performance

This project is a collaboration between the National Physical Laboratory (NPL) and Statkraft and aims to establish a novel performance metric for the accurate evaluation of oversized and bifacial photovoltaic (PV) systems. This will lead to increasing the value of future solar projects, reducing financial risks and improving fault identification, thus energy production, revenue and CO2 offsets from renewable generation.The performance ratio (PR) is the most established metric for assessing solar photovoltaic (PV) system performance in the Solar Industry. It is the ratio between the actual to the expected generation based on a system's rated power. It is widely applied as a contractual guarantee for a power plant's performance and therefore may determine the value of a project over its projected lifetime.A guaranteed PR value is agreed between parties based on software simulation of the PV system and an initial evaluation. Nevertheless, PR measurements can be strongly affected by differences between actual weather conditions during the measurement period (typically 1 year) and "typical meteorological year" data used in modelling. The most serious weather-induced errors occur on "oversized" PV systems.Oversizing occurs when a PV array has a rated DC power larger than its inverter's rated AC output power; a common practice in PV industry, which leads to inverter "clipping", outputting a flat generation curve during high insolation periods. Clipping can be exaggerated by actual weather conditions, impacting PR, especially in high insolation years. This effect is further enhanced for bifacial PV systems, which harvest additional power from the rear side of PV modules. This effectively makes the systems even more oversized and the existing performance metrics no longer reliable.Despite the proposed corrections for temperature variations, current IEC standards for performance metrics fail to assess the performance of oversized PV plants. In this project, we aim to identify an improved metric and assess its merit, in order to accurately assess the PV systems that we develop.NPL and Statkraft will define this metric for monofacial and bifacial systems and will benchmark with current standard metrics against seasonal and annual weather variability, for different PV system configurations and faults. The metric will be validated against real data, multiple locations and systems' configurations.The proposed metric will be:* Insensitive to the actual weather conditions during the evaluation period.* Sensitive to underperformance of systems compared to their expected performance given the actual weather conditions.* Simple and unambiguous to use in contracts.

该项目是国家物理实验室（NPL）和Statkraft之间的合作，旨在建立一种新的性能指标，用于准确评估超大型和双面光伏（PV）系统。这将提高未来太阳能项目的价值，降低金融风险，改善故障识别，从而提高可再生能源发电的能源产量、收入和二氧化碳抵消。性能比（PR）是太阳能行业评估太阳能光伏（PV）系统性能的最常用指标。它是基于系统额定功率的实际发电量与预期发电量之间的比率。它被广泛应用于发电厂性能的合同保证，因此可以确定项目在其预计寿命期内的价值。保证PR值由双方根据光伏系统的软件模拟和初始评估达成一致。然而，PR测量可能会受到测量期间（通常为1年）的实际天气条件与建模中使用的“典型气象年”数据之间差异的强烈影响。最严重的天气引起的错误发生在“超大”光伏系统上。当光伏阵列的额定直流功率大于其逆变器的额定交流输出功率时，会发生浪涌;这是光伏行业的常见做法，会导致逆变器“削波”，在高日照期间输出平坦的发电曲线。削波可能会被实际的天气条件夸大，影响公关，特别是在高日照年。这种效果在双面光伏系统中进一步增强，双面光伏系统从光伏模块的后侧收集额外的功率。这实际上使系统变得更加超大，现有的性能指标不再可靠。尽管提出了对温度变化的修正，但当前的IEC性能指标标准无法评估超大型光伏电站的性能。在这个项目中，我们的目标是确定一个改进的指标，并评估其优点，以准确评估我们开发的光伏系统。NPL和Statkraft将为单面和双面系统定义这个指标，并将针对不同的光伏系统配置和故障，根据季节和年度天气变化，使用当前的标准指标进行基准测试。该指标将根据真实的数据、多个位置和系统配置进行验证。建议的指标将：* 对评估期间的实际天气条件不敏感。*在实际天气条件下，对系统性能低于其预期性能敏感。*在合同中使用简单明确。