Micro-grid active injection type single-end protection method based on phase polarity characteristics
A micro-grid and injection technology, which is applied in the direction of emergency protection circuit devices, electrical components, circuit devices, etc., can solve problems such as inability to quickly and accurately distinguish faults inside and outside the zone, large amount of communication data, and complex threshold setting, etc., to achieve Good selectivity and sensitivity, elimination of coupling effects, and easy protection threshold
Active Publication Date: 2021-05-14
HUNAN UNIV
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[0005] The present invention provides a micro-grid active injection single-ended protection method based on phase polarity characteristics, which solves the problem of complex threshold setting in micro-grid protection in the prior art, which relies on communication and has a large amount of communication data, and cannot quickly and accurately distinguish between intra-area and area External faults and protection time may exceed the fault tolerance time limit of the microgrid
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[0060] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.
[0061] Such as figure 1 Shown is a typical microgrid structure diagram of the present invention, including the grid, bus 1, bus 2, bus 3, bus 4, bus 5, bus 6, three inverter-based distributed generators (inverter-based distributed generator, IBDG) IBDG1, IBDG2, IBDG3, loads L-1, L-2, L-3, interconnection transformers T-1, T-2, T-3, T-4, common connection point PCC (Point of common coupling), fast static transfer switch STS , ring network switch, f...
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The invention discloses a micro-grid active injection type single-end protection method based on phase polarity characteristics. The method comprises the following steps: firstly, acquiring three-phase voltage and current signals in real time at an m-side protection device of a protected line; obtaining harmonic voltage and harmonic current through fast Fourier transform, and further obtaining the harmonic voltage of the n side of the protected line; and then accurately judging internal and external faults of the area through the phase difference product of the phase difference between the m-side harmonic voltage and the harmonic current and the phase difference between the m-side harmonic voltage and the n-side harmonic current of the protected line. The problems that in the prior art, in microgrid protection, threshold setting is complex, the method depends on communication, the communication data size is large, internal and external faults cannot be rapidly and accurately distinguished, and the protection time may exceed the fault bearing time limit of the microgrid are solved.
Description
technical field [0001] The invention belongs to the technical field of electric power system relay protection, and relates to a micro-grid active injection single-end protection method based on phase polarity characteristics. Background technique [0002] With the widespread application of distributed power generation technology, microgrid has become an important part of power distribution system, mainly including distributed micro-sources (microturbines, diesel generators, batteries, fuel cells and renewable energy, etc.), control systems, communication equipment and Protection monitoring devices and other parts. Distributed micro-sources can realize power supply near the load, avoid long-distance transmission loss, and help improve the energy utilization efficiency of the power system. In addition, the microgrid can operate in two modes of grid-connected or island. When the large grid encounters disturbances such as voltage fluctuations and frequency deviations, it can op...
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IPC IPC(8): H02J3/38H02H7/26
CPCH02H7/26H02J3/381H02J3/388H02J2300/20
Inventor 帅智康何梨梨褚旭吴向阳黄文彭也伦罗安陈燕东
Owner HUNAN UNIV