Microgrid non-destructive island detection method based on adaptive reactive disturbance

Abstract

The invention pertains to the field of power system microgrid protection and control, and relates to a microgrid non-destructive island detection method based on adaptive reactive disturbance. The method comprises the following steps: periodic reactive disturbance is added on the reference value of IBDG reactive output, the peak value selection of a triangular wave reactive disturbance portion is related to the IBDG operating mode and the system frequency when the reactive disturbance value is zero in the last disturbance period; and if the absolute value of the frequency change rate is detected to be equal to a preset value, and the duration time reaches a time setting value, then the island state is judged. The method of the invention is simple and practicable, and can be used to minimize the total disturbance and the influences of the disturbance on the quality of electric energy.

Description

Technical field [0001] The invention belongs to the field of protection and control of micro-grids in power systems, and relates to a non-destructive island detection method for micro-grids. Background technique [0002] The occurrence of unplanned island operation of microgrid is accidental and uncertain, which will bring a series of problems to the safe and stable operation of the power system. In order to ensure the reliability and stability of power supply, the distributed generation (DG) in the microgrid needs to be able to flexibly adjust its control strategy in time, so that the microgrid can be transformed from an unplanned island operation mode to an island operation mode. Islanding detection is the prerequisite for DG to adjust its control strategy, and it plays an important role in the configuration and cooperation of protection in the microgrid. The existing islanding detection methods include switch state monitoring method, passive detection method and active d...

AI Technical Summary

Problems solved by technology

Among them, the switch state monitoring method is based on the communication technology to send the opening and closing state of the circuit breaker on the side of the distribution network to the DG to judge the operation mode of the microgrid. This method does not have detection blind spots and does not affect the power quality, but the implementation is more complicated. poor economy

The passive detection method judges the island by detecting whether the basic electrical quantities such as voltage, phase, frequency and its rate of change are within the allowable range of change. This method will not affect the power quality of the system, but there is a large detection blind spot, usually with active Combination of detection methods

The active detection method determines the island by introducing a disturbance signal into the control signal of the DG. This method reduces the detection blind area, but at the same time it also has a certain impact on the power quality

In addition, the active detection method usually needs to force the electrical quantities such as voltage and frequency to exceed its threshold value, which destroys the normal and stable operating conditions of the microgrid, and is not conducive to the conversion of DG control strategies and the island operation of the microgrid.

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