Micro power grid state estimating method based on converter control characteristics

A technology for state estimation and control characteristics, applied in AC network circuits, instruments, calculations, etc., can solve problems such as analysis of operating characteristics of AC-DC hybrid microgrids, lack of balance nodes in the system, and lack of

Inactive Publication Date: 2016-12-14
HOHAI UNIV
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Problems solved by technology

[0003] Most of the existing AC / DC hybrid microgrid state estimation algorithms are derived from the distribution network state estimation algorithm, without detailed analysis of the operating characteristics of the AC / DC hybrid microgrid itself, and lack of consideration of the following factors: 1) AC / DC hybrid microgrid operation mode (grid-connected / island); 2) There is no balance node in the system during island operation; 3) The system frequency is used as the link variable of each DG; 4) The control characteristics of the grid-connected node of the converter

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  • Micro power grid state estimating method based on converter control characteristics
  • Micro power grid state estimating method based on converter control characteristics
  • Micro power grid state estimating method based on converter control characteristics

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Embodiment

[0138] The AC / DC hybrid microgrid calculation example based on IEEE13 nodes is used for analysis, as shown in the attached image 3 shown. Consider connecting DGs with different control strategies at 2, 3, 7, and 13, and connecting DC microgrids through converters between nodes 14-15. Regarding the measurement and configuration of the AC / DC hybrid microgrid state estimation system, the attached image 3 marked in detail. The Newton-Raphson method is used to solve the power flow for the whole example, and random errors that obey the normal distribution are added to the true value of the power flow: (1) The load power measurement and the DG three-phase total power measurement are based on historical data and weather conditions The pseudo-measurement predicted by other factors, so the maximum measurement error is set to 20%; (2) The node voltage amplitude, branch current amplitude and branch power measurement are real-time measurements, so the maximum measurement error is set t...

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Abstract

The invention discloses a micro power grid state estimating method based on converter control characteristics. The method includes the steps of establishing stable state models for each component in an AC-DC hybrid micro power grid, adding Droop control type DC running state to state variables for state estimation, and configuring corresponding pseudo measurement to ensure the state estimation observability. A branch power-based measurement conversion method is provided with respect to the complex non-linear function relation between branch current amplitude and three-phase node voltage, thereby simplifying Jacobi matrix calculation. Weighted least square estimation is employed to solve the state estimation model of the AC-DC hybrid micro power grid. The state estimation problem of an AC-DC hybrid micro power grid containing Droop control type DC under grid connected / island operation modes can be effectively solved. Converter control characteristics and micro power grid island operation characteristics are taken into consideration. The micro power grid state estimating method has the advantages of rapid calculating speed and high accuracy and has good engineering application value.

Description

technical field [0001] The invention relates to a method for estimating the state of a microgrid based on the control characteristics of a converter, and belongs to the technical field of power system monitoring, analysis and control. technical background [0002] Distributed generation technology, which has dual advantages of economy and environmental protection, is becoming more and more mature, so the number of distributed generation devices in the power grid is increasing. In addition, at present, most user-side loads, renewable energy power generation and energy storage devices are connected to the grid in a DC mode. The establishment of a DC microgrid can reduce power conversion links and has the advantages of improving power utilization. However, due to the long-term development of the traditional AC transmission network, it is impossible for the DC network to completely replace the existing AC network. For this reason, the AC-DC hybrid microgrid, as a good solution ...

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Application Information

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IPC IPC(8): H02J3/00G06Q50/06
CPCG06Q50/06H02J3/00H02J2203/20
Inventor 卫志农陈和升孙国强陈胜臧海祥
Owner HOHAI UNIV
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