Main-grid Planning of Large-scale Wind-photovoltaic Power Stations Considering Fluctuation and Regulation Demand

Abstract

The centralized integration of large-scale wind and photovoltaic power stations increases output fluctuation and main-grid regulation demand. Coordinated planning is therefore required to utilize wind–photovoltaic complementarity while maintaining secure main-grid operation. Wind and photovoltaic uncertainties are described using probabilistic models and Monte Carlo scenarios. A capacity-scaled variance–covariance index is established to quantify joint output fluctuation. A coordinated planning model is then formulated considering investment cost, network loss, renewable-energy curtailment, frequency-related regulation demand, reactivepower support, voltage limits, and accommodation constraints. A generalized Nash equilibrium is adopted to coordinate the renewable-energy investment entity and the main-grid operation entity under shared security constraints. Case studies are conducted on a modified 33-node main-grid test system. The results show that access location significantly affects network loss, renewable-energy curtailment, and fluctuation performance. Under the selected access scheme, joint wind–photovoltaic planning reduces the curtailment rate to 4.26%, compared with 7.32% for photovoltaic-only planning and 6.12% for windonly planning. The corresponding network loss decreases to 40,321 MWh. Under 80%, 100%, and 120% renewable-resource scenarios, all node voltages remain within 0.95–1.05 p.u. Wind–photovoltaic complementarity reduces concentrated power injection and improves renewable-energy accommodation. The equilibrium model preserves the independent objectives of investment and operation without predefined objective weights. The proposed method reduces curtailment and network loss while satisfying main-grid security requirements, providing a coordinated planning framework for large-scale renewable-energy integration.