Method for online detection and assessment of photovoltaic system

Abstract

The invention discloses a method for online detection and assessment of a photovoltaic system, comprising steps of starting up a voltage-current scanning function through an MPPT function in a photovoltaic system, enabling output voltage of a photovoltaic array which is received by the MPPT to be from minimum working voltage state to an open circuit state or from the open circuit state to the minimum working voltage state, detecting the current value and the voltage value of the MPPT of each path in the process, collecting physic quantities of the corresponding moment like the solar radiation, environment temperature, photovoltaic assembly temperature, wind speed, wind direction, etc, utilizing collected data to adopt a fitting method to establish a photovoltaic power calculation model, combining and utilizing leave factory parameters of the photovoltaic assembly or an initial photovoltaic power calculation model which is established by a PVsyst database, and calculating energy efficiency indexes of each link and obtaining an energy efficiency analysis result after the faulted time frame is eliminated. The invention realizes the online detection of various physic parameters of the photovoltaic system, the photovoltaic array modeling and calculation and analysis of the energy efficiency index of each link.

Description

Technical field [0001] The invention relates to the technical field of photovoltaic power generation systems, in particular to a method for online detection and evaluation of the efficiency of photovoltaic systems. Background technique [0002] Solar photovoltaic power generation is currently the main form of renewable energy power generation, and it is also the dominant energy supply body in the future. At present, my country's subsidies for photovoltaic power generation have changed from the original installed capacity subsidies to electricity price subsidies. Therefore, the power generation of the photovoltaic system throughout its life cycle has become the most important factor affecting the economic benefits of photovoltaic power plants. However, some solar photovoltaic power plant projects in my country currently have problems such as low quality and low power generation efficiency. At the same time, there are no clear standards and access thresholds for the comprehensive q...

AI Technical Summary

Problems solved by technology

However, since there is no reliable instrument to measure MPPT efficiency at present, and it is not necessary to measure MPPT efficiency during inverter certification, most manufacturers do not provide MPPT efficiency indicators, or provide falsely high MPPT efficiency in the technical specifications of photovoltaic inverters Indicators, such as marked as 99%, some even marked as 99.9%

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