Optimal configuration of hybrid AC/DC urban distribution networks for high penetration renewable energy

Abstract

Existing AC medium voltage distribution networks are facing challenges on handling increasing loads and renewable energy integrations. However, it is very difficult to build new distribution lines in urban areas. This paper proposes a configuration method of hybrid AC/DC medium voltage distribution networks, in which some existing AC lines are converted to DC operation. Existing topologies and dispatching scenarios are considered during configuration because the overall power flow can be rescheduled in the hybrid AC/DC distribution network. Therefore, transfer capacities of the lines are fully utilized, and more renewable energies are accommodated. A bi-level programming model is established embedding chance constraint programming to consider the intermittent output of renewable energy. In the upper level, a multiple objective optimal model is proposed in order to balance investments, power losses, and the maximum load level and renewable energy capacity. In the lower level, daily operations of the newly installed VSCs are optimized by a chance constraint programming. The influences of energy storage systems on the configuration are also analysed. Simulations studies are performed to verify the proposed method.

Optimal Power Flow Control in Parallel Operating AC and DC Distribution Links

“…The paper explores the trade-offs between accuracy and speed of the derived model for different problem sizes. For an urban distribution network with few existing lines refurbished from ac to dc operation, [15] optimizes the system topology of the resultant hybrid ac/dc grid considering investments and power losses while accommodating renewable energy resources and fully utilizing the transfer capacity. Network reconfigurability of a hybrid ac-dc distribution grid is explored for optimal operation by using a communication based two-stage energy management system in [16].…”

“…Similarly, η SSS (i) and η RSS (i) are iteratively determined functions of y. According to (11), the first derivative of total system losses P L,sys with respect to y can be found from (15).…”

Research on energy storage depth planning of AC / DC distribution network based on toughness enhancement technology

“…i h x  represents the chance constraint for the model establishment [19][20] .  represents the confidence level of the chance constraint condition.…”

Holomorphic embedding approach for VSC‐based AC/DC power flow

“…In recent years, with the increasing renewable energy integration into power networks, there is a growing tendency for the existing power systems to develop into hybrid AC/DC systems, and voltage source converter based high-voltage direct current (VSC-HVDC) has emerged as an effective instrument for addressing the shortage of transmission corridors and accommodating large-scale renewables [1][2][3][4]. In the meantime, power flow analysis is becoming increasingly significant for planning, operation, and control of VSC-based AC/DC systems [5][6][7][8].…”