Micro-grid fault positioning method based on fault feature active construction

Abstract

The invention discloses a micro-grid fault positioning method based on fault feature active construction. The method comprises the steps that a micro power supply calculates a fault current instruction according to a grid-connected point positive sequence fault voltage component; the micro-grid protection device judges the fault direction according to the phase relation of the positive sequence fault component; the micro-grid protection system collects fault direction information of the protection device and locates a line where a fault point is located. According to the method, the fault characteristics capable of being used for judging the fault direction are constructed in the micro-grid through micro power supply fault control, the protection system can accurately position the fault line of the micro-grid by using the characteristics, the detection result is accurate and reliable, and the method has relatively high operability.

Description

technical field [0001] The invention relates to micro-grid fault location technology, in particular to a micro-grid fault location method based on active construction of fault features. Background technique [0002] Microgrid is an important part of smart grid and has broad application prospects. However, in the actual operation process, due to the constraints of insulation level, operating environment, equipment aging and other factors, various faults will inevitably occur in the microgrid. In order to ensure the reliability of power supply for users, the microgrid must remove faulty equipment quickly and accurately. Although the microgrid and the distribution network have similar radial feeder structure and voltage level, it is generally believed that the three-stage current protection scheme used in the distribution network is no longer suitable for the microgrid. The main reasons are as follows: 1 ) Most of the micro-power sources in the micro-grid are inverter-type mi...

AI Technical Summary

Problems solved by technology

Although the microgrid and the distribution network have similar radial feeder structure and voltage level, it is generally believed that the three-stage current protection scheme used in the distribution network is no longer suitable for the microgrid. The main reasons are as follows: 1 ) Most of the micro-power sources in the micro-grid are inverter-type micro-power sources (the micro-power sources mentioned later refer to inverter-type micro-power sources), and their maximum fault output current is generally limited to within 2 times the rated current; 2) The micro-grid has There are two operating modes: island and grid-connected, and the output power of some micro-power sources is not constant, resulting in a large uncertainty in the fault current level of the micro-grid

In addition, the micro-power fault control method also has a significant impact on the fault response characteristics of the micro-grid, which directly affects the fault status of the micro-grid and the reliability of protection actions.

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