A method for compute continuous power flow in AC/DC hybrid microgrid

Abstract

The invention discloses a method for calculate continuous power flow of AC / DC hybrid micro-grid include such steps as forming two types of AC / DC hybrid micro-grid operation system and nine types of node, adopting LM (Levenberg-Marquardt with a nonmonotone line search (LMNL) algorithm and alternating iterative method based on LMNL algorithm are used to solve the initial point of continuous power flow of AC / DC microgrid subsystem and AC / DC interconnected microgrid respectively. A two-way iterative predictive correction method combining tangent prediction and combined Newton correction is used topredict and correct the AC / DC interconnected microgrid. The conventional power flow calculation method based on LMNL algorithm proposed in this paper is applicable to the conventional power flow calculation of different types of microgrids. The proposed two-way iterative prediction and correction method solves the complex and diverse problem of AC / DC power coupling and continuous power flow calculation under different AC and DC loads. The method of the invention is applicable to continuous power flow calculation of AC / DC hybrid microgrid under various operation modes, and has good engineeringapplication value.

Description

technical field [0001] The invention relates to the field of power system analysis, in particular to a continuous power flow calculation method for an AC-DC hybrid micro-grid. Background technique [0002] According to the power supply form of the main network, the microgrid can be divided into AC microgrid, DC microgrid and AC-DC hybrid microgrid. The AC-DC hybrid microgrid refers to a microgrid that contains AC and DC buses and an interlinking converter (ILC) that connects the AC and DC buses, and can directly supply power to both AC loads and DC loads. Some scholars also define AC-DC hybrid microgrid as a power network that contains both AC microgrid and DC microgrid. Compared with the AC microgrid and DC microgrid with a single power supply form, the AC-DC hybrid microgrid has many characteristics and advantages. The AC-DC hybrid microgrid will be the preferred microgrid model for the efficient development and utilization of distributed renewable energy, and the AC-DC ...

AI Technical Summary

Problems solved by technology

There is an essential difference between the conventional power flow calculation of AC microgrid without balance nodes and the AC distribution network with DG, and the conventional power flow algorithm and its deformation of traditional distribution network will no longer be applicable; the steady-state frequency It is not pre-specified, but an unknown state variable, and the system frequency will change with the change of load parameters. When the frequency deviates too much from the rated value, the system will collapse, and its continuous power flow needs to calculate the power-frequency curve; in addition, AC and DC In the interconnected microgrid, when the ILC is the power supply of one subsystem, it is also the load of another subsystem. There is a coupling relationship between AC and DC power, and the calculation of the initial point and correction link of the continuous power flow is different from that of the microgrid with a single power supply form.

Therefore, the continuous power flow calculation of the AC-DC hybrid microgrid under different operating modes is complicated and diverse.

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