The fault analysis of hybrid AC/DC systems and the planning of HVDC transmission systems have been widely investigated in the past decades [6]. Aghaei et al. presented a multi-objective optimization algorithm for the MDEP (Multi-Stage Distribution Expansion Planning).
The objective functions of the MDEP consist of various factors, including short circuit capacity. A modified PSO (Particle Swarm Optimization) method is used for solving the nonlinear model
Wasserrab and Balzer [8] analyzed both line-to line and line-to-ground faults at different locations in a hybrid AC/DC system.
Gilles [9] presented the formulation for solving the single-stage HVDC transmission expansion planning to reinforce AC networks. In this formulation, the detailed model of DC transmission systems is adopted instead of sensitivity coefficients.
Kuruganty and Woodford [10] proposed a methodology for a reliability cost-benefit analysis of HVDC transmission expansion planning
Different factors such as forced outages of the generation and transmission are considered in the methodology. Chamorro et al.
studied transmission expansion planning from economics perspective. A valuation model combining optimization techniques is proposed and Monte Carlo simulation is utilized to assess the lifetime benefits of the expansion project.
This model and approach is theoretically applied for Western HVDC subsea link between England/Wales and Scotland. Urquidez and Xie [12] proposed the concept of targeted conversion of AC lines to DC lines for improved economic dispatch.
By incorporating the converted HVDC, transmission congestion is relieved and economic benefits for renewable energy integration are improved. Asad and Kazemi [13] presented a novel distributed optimal power sharing (ODCPS) method for planning radial dc microgrids.