Microgrid protection method based on two-stage fault adjustment and superposed components

A micro-grid and fault technology, applied in emergency protection circuit devices, electrical components, single-grid parallel feeding arrangements, etc., can solve the problems of relying on original sample accumulation, lack of theoretical support for feature quantity acquisition, etc.

Active Publication Date: 2021-02-26
XIAN UNIV OF TECH
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  • Claims
  • Application Information

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Problems solved by technology

Although the combination of digital signal algorithm and artificial intelligence algorithm can deeply mine fault information to a certain

Method used

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  • Microgrid protection method based on two-stage fault adjustment and superposed components
  • Microgrid protection method based on two-stage fault adjustment and superposed components
  • Microgrid protection method based on two-stage fault adjustment and superposed components

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Experimental program
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Embodiment

[0144] established as Figure 8 The microgrid model of Figure 8 Note: DG1~DG4 are 4 identical DG units controlled by droop, with a capacity of 100kW, a switching frequency of 6kHz, and a DC voltage of 800V; the resistance and inductance parameters of the line are 0.642Ω / km and 0.083H / km km, the line lengths are 0.3km, 0.2km and 0.5km in turn. Its load parameters are shown in Table 1.

[0145] Table 1 Load parameters

[0146]

[0147] Case 1: A three-phase short-circuit fault occurs in line 1 of the microgrid at 0.1s, and the fault distance is 200m.

[0148] Due to the three-phase short-circuit fault, the instantaneous value of the current of each phase reaches the starting condition of the first stage of fault regulation, and no further judgment is required. Figure 9(a)-Figure 9(c) Give the superimposed components of a on bus 1 and bus 2 and their magnitude-frequency and phase-frequency diagrams. Table 2 gives the phase angle of the DC component, the phase angle of t...

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Abstract

The invention discloses a microgrid protection method based on two-stage fault adjustment and superposed components. The method comprises the steps: proposing a microgrid fault adjustable frame through employing an active filter; on the basis of the framework, providing a two-stage fault adjustment method for fault current characteristics of a distributed power supply, so that flexible adjustmentof the microgrid under the fault condition and consistency of control strategies between strong and weak faults are achieved; solving the cosine values of the phase angles of adjacent buses to construct a characteristic difference direction on the basis of extracting phase angles of superimposed direct-current components and fundamental frequency components on each bus; and when a number smaller than 0 exists in the characteristic difference direction, determining that a fault state exists, and otherwise, determining that the system is in a normal operation state.

Description

technical field [0001] The invention belongs to the technical field of relay protection for power system distribution networks, and in particular relates to a micro-grid protection method based on two-stage fault regulation and superposition components. Background technique [0002] Distributed power generation technology based on renewable energy is an important technical means to deal with energy crisis and environmental pollution. In order to make more effective use of distributed power generation technology, micro-grid technology came into being. It is a medium and low voltage distribution network system composed of wind or solar distributed generation units (Distributed Generation, DG) and loads. However, due to the flexible operation mode, topology structure and power electronic device control method of the microgrid, the traditional distribution network protection method is no longer applicable. Therefore, the microgrid protection method has become a hot research top...

Claims

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Application Information

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IPC IPC(8): H02H7/26H02J3/38
CPCH02H7/26H02J3/38
Inventor 王晓卫高杰魏向向贾嵘梁振锋党建王开艳张惠智王艳婷
Owner XIAN UNIV OF TECH
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