Fault detection method and system suitable for photovoltaic grid-connected system

Abstract

The invention discloses a fault detection method and system suitable for a photovoltaic grid-connected system. The method comprises the steps of (A) calculating maximum output power of a photovoltaic array under a current environment condition; (B) calculating theoretical maximum output power of the photovoltaic array under the current environment condition by combining the control efficiency of an MPPT controller and the efficiency of a grid-connected inverter according to the maximum output power; (C) detecting and obtaining current actual output power of the photovoltaic array; and (D) comparing the theoretical maximum output power with the actual output power and judging that a fault appears in the photovoltaic array when the difference between the theoretical maximum output power and the actual output power exceeds a preset threshold. The fault detection method belongs to an online detection method; the fault condition of a photovoltaic system can be timely reflected; timely maintenance by engineers is facilitated; various energy conversion links in the photovoltaic grid-connected system are considered in the detection process; the fault detection method has relatively high accuracy; and meanwhile, estimation of the total generating capacity of the photovoltaic system can also be achieved.

Description

technical field [0001] The invention relates to the technical field of photovoltaic fault detection, in particular to a fault detection method and system suitable for a photovoltaic grid-connected system. Background technique [0002] With the increasingly prominent environmental problems, the emergence of problems in the stability, reliability and safety of traditional wide-area power grids has forced people to turn their attention to the utilization of clean and green renewable energy. The solar photovoltaic industry has huge market potential and development space. Not only has it maintained a growth rate of more than 50% in the past 10 years, it will continue to expand rapidly in the next 10 years. With the rapid expansion of the number and scale of distributed photovoltaic power generation systems, the maintenance of photovoltaic systems has increasingly become a heavy burden for operating organizations. Photovoltaic systems usually operate unattended, and system failur...

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Problems solved by technology

[0004] In view of the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a fault detection method and system suitable for photovoltaic grid-connected systems, aiming to solve the problem of inconvenient maintenance in time when the existing photovoltaic system fails, resulting in Problems with reduced system output power and efficiency

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