Analysis of Parameter Influence on Transient Active Power Circulation Among Different Generation Units in Microgrid

摘要

With the employment of power electronic converters, renewable energy resources introduce noticeable diversity into different generation units and dramatically change the characteristics of the supply side. Cooperation of different kinds of generation units in steady and dynamic states hence becomes important issues for grid integration. This article studies transient active power circulation caused by parameter difference among different kinds of generation units, such as synchronous generator and voltage-controlled power inverters. Parameter differences brought by power electronic inverters are analyzed, including capacity, inertia, and grid-side inductance. Moreover, a simplified transfer function model is utilized for the detailed analysis, which reveals how the transient active power circulation is influenced by the parameter difference. The theoretical analysis is verified with both simulation and experiment. Consequently, some important conjoint influences of inertia, impedance, and capacity difference are clarified, where the effectiveness and ineffectiveness of inertia and impedance imitation are concluded in transient active power allocation. Inertia and impedance design that attenuates transient active power circulation is proposed in several certain situations for inverter cooperated with other generation units.