Positive feedback island detection method based on active current disturbance

A technology of active current and island detection, which is applied in the direction of measuring electricity, measuring devices, and measuring electrical variables, etc., can solve the problems that the islanding effect cannot be completely detected, and achieve the effect of improving the detection range of islands and making the upper and lower limits simple

Inactive Publication Date: 2016-04-06
DONGFANG HITACHI CHENGDU ELECTRICAL CONTROL EQUIP CO LTD
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Problems solved by technology

The active islanding detection method is commonly used active frequency shift method and reactive power disturbance method. The active frequency shift method will affect the harmonics of the output current of the inverter device. Rarely used, the reactive power disturbance method has detection blind spots under high quality factors, and cannot fully detect islanding effects under different quality factors

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  • Positive feedback island detection method based on active current disturbance
  • Positive feedback island detection method based on active current disturbance
  • Positive feedback island detection method based on active current disturbance

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Embodiment Construction

[0019] A positive feedback islanding detection method based on active current disturbance of the present invention will be further described below in conjunction with the accompanying drawings.

[0020] Such as figure 1 as shown, figure 1 It shows the positive feedback relation diagram between the given active current and the output voltage of the inverter device equipped with the above islanding detection algorithm when islanding occurs. Through the influence of the D-axis component of the output current of the inverter device in the synchronous rotating coordinate system on the voltage of the grid-connected point, the judgment of whether the islanding effect occurs can be realized by the formula (1) It can be seen that as long as the phase lock is accurate, almost zero, the output power Basic subject and affect, while Since it is not easy to change under the control of the grid, only Can have a large degree of freedom to change ; by formula (2) It can be se...

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Abstract

The invention provides a positive feedback island detection method based on active current disturbance. The detection method comprises four portions: grid-connected point voltage vector angle calculating, D axis control coefficient calculating of an output current under a synchronous rotating coordinate system, grid-connected current control and grid-connected point overvoltage/undervoltage, and overfrequency/underfrequency protection. Through carrying out disturbance control on an active current of an inversion apparatus, the inversion apparatus can be guaranteed not to influence a harmonic distortion rate of the output current during normal operation; and when an island is generated, the island detection method can be guaranteed not to be used to detect a blind area so that an island detection scope is greatly increased. Simultaneously, because of the positive feedback, a detection speed can easily satisfy a standard requirement. In addition, because an normal operation scope of the inversion apparatus is determined in a standard, determination of an upper limit and a lower limit of a D axis component after low-pass filtering is simple.

Description

technical field [0001] The invention relates to an islanding detection method for a three-phase grid-connected power generation system, in particular to an active positive feedback islanding detection method for a distributed grid-connected power generation system, and belongs to the field of grid detection for three-phase grid-connected inverters. Background technique [0002] In a distributed power generation system composed of a grid-connected inverter and the grid, the load near the grid-connected point of the inverter device is jointly powered by the inverter device and the grid. When the output power of the inverter device matches the power of the load and the grid end of the load When the power supply is stopped due to a fault, the inverter device may continue to supply power to the load, thereby forming an island operation state outside the grid. The islanding state will make some lines that are considered to be disconnected from the grid live, which will pose a thre...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/00
CPCG01R31/00
Inventor 荣先亮彭良平汤济泽孙震宇杜毅
Owner DONGFANG HITACHI CHENGDU ELECTRICAL CONTROL EQUIP CO LTD
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