The Impact of a High Proportion of Distributed Pv on the Operation of Regional Active Isolated Networks

In the process of large-scale failure development of 220 kV main network in megacities, to retain the operation of a few units of the main network, the local main network containing them will be actively decommissioned. This isolated network serves as the last line of defense against power grid collapse and functions as a black start power source for rapid fault recovery in the main network. The expansion of distributed PV in megacities' distribution networks necessitates an investigation into the impact of high fluctuations in distributed PV on active island operational modes. To illustrate this, a simulation model is established by using a major urban area's 220 kV active isolated network as an example. Three scenarios are simulated: no <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{PV}, 10 \% \text{PV}$</tex>, and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$20 \% \text{PV}$</tex>, to analyze frequency, voltage, and power angle fluctuations under normal operation and extreme variations in both PV generation and load demand. Analysis of simulation results reveals that a significant increase in distributed photovoltaic integration compromises flexibility and stability within the active isolated network, thereby increasing scheduling complexity. Based on these research findings, recommendations are proposed to ensure the safe and stable operation of active islands.