To address the current challenges including increasing penetration of wind-solar renewable energy sources

drastic reduction of system inertia

poor frequency stability

insufficient overall regulation capability

and source-load spatial mismatch

this paper proposes a coordinated planning method for hydro-wind-solar-pumped storage systems with consideration of frequency security and chance constraints. Firstly

detailed modeling is conducted on hydropower stations

hybrid pumped storage stations

wind power stations

solar power stations

battery storage stations

and DC transmission constraints. Maximization of system net profit is set as the optimization objective

which takes into account electricity sales revenue as well as the construction and investment costs of wind

solar and pumped storage facilities. Secondly

a frequency security constraint model is established

which considers the emergency adjustment of DC power to support frequency stability. Thirdly

to handle the stochastic nature of wind and photovoltaic output

an uncertainty model based on chance constraints is developed

and the robust expansion formulation of sample average approximation is adopted to transform chance constraints for tractable computation. Case study results show that the proposed model effectively achieves a coordinated planning and configuration of hydro-wind-solar-pumped storage. Combined application of chance constraints and frequency security constraints facilitates rational installed-capacity planning from a theoretical perspective to cope with renewable output volatility and system frequency security risks.