Passive island detection method

An island detection and passive technology, applied in the direction of measuring electricity, measuring devices, measuring electrical variables, etc., can solve the problems of output power quality influence, large dead zone, etc., and achieve the effect of no dead zone detection

Active Publication Date: 2018-12-11
JIANGSU GOODWE POWER SUPPLY TECHNOLOGY CO LTD
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Most of the existing island detection methods are active disturbance detection methods, which will affect the quality of output power
However, the existing passive detection methods are generally phase change and frequency change detection methods, and these methods have the problem of excessively large dead zones.

Method used

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Examples

Experimental program
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Embodiment 1

[0044] Embodiment one: as attached figure 1 As shown, a passive islanding detection method, the method is: when the power generation system is connected to the grid, the following steps are performed in each grid cycle:

[0045] Step 1: Set the current as the Nth grid cycle, and obtain the Nth grid cycle value T of the grid-connected point voltage N and the N-2 grid cycle value T N-2 , and calculate the period value deviation Td=T N -T N-2 , and then go to step 2.

[0046] Step 2: Determine the relationship between the period value deviation Td and the set value. When the period value deviation Td is greater than the set value, perform step 3. When the period value deviation Td is less than or equal to the set value, perform step 4.

[0047] In this step, the set value is determined according to the actual power grid frequency jitter state, so as to ensure that the island state is not falsely detected.

[0048] Step 3: Add 1 to the island occurrence count variable, and th...

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Abstract

The invention relates to a passive island detection method. The passive island detection method includes the steps: after a power generation system is connected to the grid to run, determining the magnitude relationship between a period value deviation of a grid-connected point voltage and a set value in each grid period, and determining whether the effective value of the total harmonic voltage and the average value of a plurality of consecutive grid periods satisfy the preset conditions at the same time, counting the corresponding island occurrence count variable in the above process, and finally, determining whether the island state occurs according to the counting result of the island occurrence count variable. The passive island detection method solves the problem that a conventional island detecting method uses the active disturbance mode, thus influencing the power quality, or uses the passive mode but has a large dead zone. The passive island detection method can detect the island state quickly without dead zones by combining the two parameter characteristics of the voltage point and the harmonic of the grid point, and has no influence on the power quality because of the passive mode.

Description

technical field [0001] The invention belongs to the field of distributed power generation (such as photovoltaic power generation), and specifically relates to an islanding detection method related to inverter grid-connected safety regulations. Background technique [0002] Most of the existing islanding detection methods are active disturbance detection methods, which will affect the output power quality. However, the existing passive detection methods are generally phase change and frequency change detection methods, and these methods have the problem that the dead zone is too large. Contents of the invention [0003] The purpose of the present invention is to provide a passive island detection method that does not affect power quality and reduces dead zones. [0004] In order to achieve the above object, the technical scheme adopted in the present invention is: [0005] A passive island detection method, the method is: after the power generation system is connected to ...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCG01R31/088
Inventor 鲁海波徐卫军刘滔黄敏方刚卢进军
Owner JIANGSU GOODWE POWER SUPPLY TECHNOLOGY CO LTD
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