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Photovoltaic grid-connected power generation system island detection method

A grid-connected power generation and island detection technology, applied in photovoltaic power generation, AC network circuits, electrical components, etc., can solve problems that endanger the personal safety of maintenance personnel and equipment damage, and achieve small impact on power quality, fast island detection, and strong engineering The effect of applying value

Inactive Publication Date: 2017-06-20
姚秋丽
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Problems solved by technology

When the photovoltaic grid-connected power generation system is in an island operation state, serious consequences will occur. For example, the voltage and frequency in the island

Method used

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  • Photovoltaic grid-connected power generation system island detection method
  • Photovoltaic grid-connected power generation system island detection method
  • Photovoltaic grid-connected power generation system island detection method

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[0014] figure 1 Where Q is the grid-connected circuit breaker, and the universal resistor R, inductance L and capacitor C are selected in parallel as the load of the system, and the load impedance is Z at this time. When the circuit breaker Q is closed, the PV system is connected to the grid and the power provided by the PV system to point a is P+jQ, the active power and reactive power obtained by the load, and the power provided by the grid are △P and △Q. After islanding occurs, if △P or △Q is very large, indicating that the output power of the PV system does not match the load power, the output voltage or frequency of the PV system will change greatly. When the voltage or frequency changes beyond the normal range, the protection circuit is The occurrence of islands can be detected.

[0015] When the PV system is connected to the grid, its output current harmonics will flow into the grid through the common coupling point a. Because the network impedance of the power grid is ver...

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Abstract

A photovoltaic grid-connected power generation system island detection method includes three parts: a photovoltaic system, voltage harmonic detection and voltage feedforward positive feedback disturbance detection. The novel island detection method introduces the positive feedback to make the voltage of a common coupling point become unstable, and adds the disturbance quantity to break a voltage balance state that may occur after the occurrence of the island, achieves fast island detection when a single or multiple PV grid-connected systems are in operation, eliminates a detection blind area in a traditional island detection method. The method is simple to implement, has little influence on the power quality, and has strong engineering application value.

Description

technical field [0001] The invention relates to a photovoltaic grid-connected power generation system, in particular to an island detection method for a photovoltaic grid-connected power generation system. Background technique [0002] Energy shortage and environmental degradation are increasingly serious global problems. Human beings are actively developing renewable energy technologies in pursuit of sustainable development. As one of the renewable energy sources, solar energy has attracted increasing attention from governments and energy experts around the world in recent years. In China, power shortage is already a very serious problem, and photovoltaic grid-connected power generation is expected to alleviate this tense situation in the future. When more and more solar photovoltaic (Photo voltaic, PV) systems are connected to the grid, it brings a new phenomenon of grid protection - the island phenomenon. [0003] The island phenomenon means that when the power grid is...

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Application Information

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IPC IPC(8): H02J3/38G01R31/08
CPCG01R31/08H02J3/383H02J3/388Y02E10/56
Inventor 姚秋丽
Owner 姚秋丽
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