Self-adaptation positive sequence current quick breaking protection method for power grid containing inverter-based DG (distributed generation)

Abstract

The invention relates to a self-adaptation positive sequence current quick breaking protection method for a power grid containing inverter-based DG (distributed generation). The method includes the steps of firstly, allocating a breaker and a protecting device at the tail end of the upstream circuit of the grid connection point of IBDG (inverter-based DG), and allocating direction elements to the protections of the upstream circuit of the IBDG, wherein the head end and tail end of the upstream area of the IBDG only needs to reflect positive-direction faults; secondly, selecting different positive sequence current setting formulas to perform current setting according to different fault types and protections at different positions; for the protections of the upstream circuit of the IBDG, performing fault direction judgment first, and selecting corresponding positive sequence current setting formulas according to fault types. By the method, influence of factors such as IBDG capacity (or output), fault point positions and system operation manners on protection ranges can be reduced or eliminated, and protection performance is improved.

Description

Technical field [0001] The invention belongs to the field of power system distribution network protection and control, and relates to an adaptive positive sequence current protection method suitable for an inverter-type DG distribution network. Background technique [0002] Distributed generation (DG) is an emerging power source, including photovoltaic power generation system, wind power generation system, micro gas turbine power generation system, small hydropower and so on. Distributed power generation technology has a series of advantages such as environmental protection and economy. It can well meet people's requirements for power security, stability, economic and environmental protection. It has attracted widespread attention and has been gradually promoted and developed. [0003] Most of the traditional medium and low voltage distribution networks are radial networks that supply power to the load in one direction. The protection does not consider the situation of DG ac...

AI Technical Summary

Problems solved by technology

The access of DG changes the fault current distribution of the distribution network and the basic conditions of the original protection configuration of the distribution network. The original three-stage current protection may malfunction or refuse to operate

In addition, for inverter-based distributed generation (IBDG) such as photovoltaic power generation systems and permanent magnet direct-drive fans, their output randomly fluctuates greatly with changes in natural conditions, and the operating mode of the system is also more variable. This makes it difficult to set the fixed value of traditional current protection, and it is also difficult to coordinate the coordination between protections.

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