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Keywords

voltage hierarchical control of distribution network; droop coefficient optimal control of PV inverter;adaptive droop control of energy storage;SOC balance control of energy storage

Abstract

In recent years, the penetration rate of distributed photovoltaic (PV) in the distribution network has been continually increasing. When the output of PV and load are not matched, the voltage of the distribution network will easily exceed the limit, which will affect the safe and stable operation of the distribution network. In this paper, a voltage hierarchical control method for distribution network is proposed considering the participation of distributed PV’s reactive power and energy storage’s active power. First, the high/low voltage problem caused by the spatio‑temporal mismatch between distributed PV and load is analyzed. Based on the distribution network topology and line parameters, the reactive power‑voltage and active power‑voltage approximate sensitivity matrices of the node voltage and injected power in the distribution network are calculated. Second, in the first layer of control, and a reactive power‑voltage droop coefficient optimization control method is proposed for distributed PV to participate in voltage regulation. The optimal droop coefficient of distributed PV inverter is obtained by solving the voltage optimization model, then the reactive power output can be calculated correspondingly. When the reactive capacity of the PV inverter is insufficient, the second layer of control is proposed, that is, the active‑voltage adaptive droop control strategy in which energy storage can participate in voltage regulation. The droop control coefficient of the energy storage is adjusted adaptively according to the state of charge (SOC) of energy storage and the local bus voltage, and the capacity of energy storage is also considered. In this way, the relative balance of energy storage power and SOC can be realized. Finally, a real 10‑bus distribution network is used as an example to verify the effectiveness of the proposed method.

DOI

10.19781/j.issn.1673-9140.2023.05.011

First Page

111

Last Page

120,215

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