Method for detecting island of photovoltaic grid-connecting system based on non-blind area self-adaptive AFDPF (active frequency drift positive feedback) algorithm

An island detection and self-adaptive technology, applied in the direction of measuring electricity, measuring devices, measuring electrical variables, etc., can solve the problem that active detection is difficult to achieve no blind spots and ensure power quality, so as to eliminate detection blind spots, improve detection efficiency, The effect of avoiding harmonic pollution

Inactive Publication Date: 2017-06-13
HARBIN UNIV OF SCI & TECH
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Problems solved by technology

Relatively speaking, in principle, active detection reduces the detection blind area, improves detection efficiency, and greatly enha

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  • Method for detecting island of photovoltaic grid-connecting system based on non-blind area self-adaptive AFDPF (active frequency drift positive feedback) algorithm
  • Method for detecting island of photovoltaic grid-connecting system based on non-blind area self-adaptive AFDPF (active frequency drift positive feedback) algorithm
  • Method for detecting island of photovoltaic grid-connecting system based on non-blind area self-adaptive AFDPF (active frequency drift positive feedback) algorithm

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specific Embodiment approach 1

[0031] Specific implementation mode one: combine figure 1 Describe this embodiment, the islanding detection method of the photovoltaic grid-connected system based on the non-blind zone adaptive AFDPF algorithm of this embodiment is as follows figure 1 As shown, the specific steps are:

[0032] Step a. Add an initial disturbance to the frequency of the output current of the photovoltaic inverter, and set the truncation coefficient of the initial disturbance to cf 0 =0.02;

[0033] Step b. Obtain the voltage frequency f when the voltage of the public coupling point of the photovoltaic grid-connected system and the power grid crosses zero through the phase-locked PLL acquisition circuit PCC , to determine whether the voltage frequency of the common point of the power grid exceeds the frequency fluctuation range of 50Hz±0.05Hz under the condition of stable operation of photovoltaic grid-connected, if it is within the fluctuation range, return to step a to enter the loop, if not ...

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Abstract

The invention relates to the field of control of a photovoltaic grid-connecting power generation system, in particular to a method for detecting island of a photovoltaic grid-connecting system based on a non-blind area self-adaptive AFDPF (active frequency drift positive feedback) algorithm. The method for detecting the island of the photovoltaic grid-connecting system based on the non-blind area self-adaptive AFDPF algorithm has the advantages that the detection blind area is further eliminated, and the influence to power quality is decreased; under the condition of relative stable frequency, the AFDPF algorithm applies a smaller disturbance; when the frequency deviates from a stable state, the positive feedback on the frequency deviation is introduced into the disturbance; before the disturbance is applied, the frequency deviation direction is judged according to a frequency deviation function; by establishing the relationship of the positive feedback coefficient is in self-adaptive change along with the public coupling point frequency, and improving the frequency deviation function of the positive feedback, the detection blind area is further eliminated, the detection efficiency is improved, and the pollution to electric energy due to introducing of larger disturbance is certainly avoided.

Description

technical field [0001] The invention relates to the control field of a photovoltaic grid-connected power generation system, in particular to an island detection method for a photovoltaic grid-connected system based on a non-blind zone self-adaptive AFDPF algorithm. Background technique [0002] With the in-depth development of the global energy strategy, the application of new energy has gradually become a research hotspot. As one of the most abundant renewable energy sources and an important clean energy source, photovoltaic resources have a profound impact on solving the shortage of petrochemical energy and severe environmental problems. The most important part of photovoltaic application is photovoltaic grid-connected power generation. [0003] In the application of photovoltaic grid-connected power generation system, when the power supply of the grid is interrupted due to electrical failure, misoperation or natural factors, each photovoltaic grid-connected power generat...

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Application Information

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IPC IPC(8): G01R31/08
CPCG01R31/088
Inventor 宋立新刘斯琦
Owner HARBIN UNIV OF SCI & TECH
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