@article{ZHOU2026, 
author = {Qi ZHOU and Yazhou LÜ and Yong HE and Zhaowei LI and Wei LI},
title = {Analysis of frequency regulation capability of large-scale hydro-photovoltaic complementary new energy bases via inter-regional DC outward transmission},
year = {2026},
journal = {Electric Power Engineering Technology},
volume = {45},
number = {7},
pages = {80-92},
keywords = {frequency response model, hydro-photovoltaic complementation, sending-end power grid, DC outward transmission, large-scale new energy base, frequency regulation capability},
url = {https://www.sciopen.com/article/10.12158/j.2096-3203.2026.07.008},
doi = {10.12158/j.2096-3203.2026.07.008},
abstract = {Under the context where the dual-carbon goals fuel the transformation of energy structure and large-scale hydro-photovoltaic complementary bases in Southwest China are emerging as the core of inter-regional energy transmission, the large-scale integration of renewable energy reduces the synchronous support capability of the sending-end power grid. Traditional thermal power units respond slowly in frequency regulation, and photovoltaic generation can only provide short-term support due to energy constraints, leading to frequency regulation power deficits and instability during cross-regional transmission. To address these issues, this paper develops a new mode that utilizes active power reserves of hydro-photovoltaic complementary bases to ensure frequency security in long-distance transmission. Firstly, an active power-frequency coupled active support control strategy for the hydro-photovoltaic complementary system is proposed, and models of photovoltaic virtual inertia and hydropower frequency response are constructed. Then, taking the cross-regional sequential control signal of the DC system as a disturbance, a frequency response model of the sending-end power grid that takes into account the frequency regulation capability of hydro-photovoltaic complementation is established. The external transmission capacity of frequency regulation active power is quantitatively analyzed, and parameter sensitivity analysis is performed. Finally, simulations are carried out using MATLAB/Simulink. The results show that under the hydro-photovoltaic complementary mode, the nadir frequency of the sending-end power grid is significantly improved, with a steady-state frequency deviation of –0.190 Hz, which is superior to the –0.517 Hz observed with thermal power alone. Increasing grid damping and inertia can mitigate frequency drops; however, due to the dependence of photovoltaics on solar irradiance, their long-term active power modulation capability is limited. The conclusion indicates that large-scale hydro-photovoltaic complementary bases can serve as new regulation resources for long-distance active power support, positively contributing to the frequency stability of the sending-end power grid and providing technical support for secure and stable cross-regional transmission of renewable energy.}
}