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This work develops a mathematical formulation to determine the combinatorial search space of the Offshore Wind Transmission Optimization Problem (OWTOP). The model accounts for Capital Expenditures (CAPEX), Corrective Maintenance (CM), losses and Expected Energy Not Transmitted (EENT) and determines the optimal radial transmission system topology to connect a number of Offshore Wind Power Plants (OWPPs) to the shore. The model also considers the stochastic nature of wind. In this context a greedy search algorithm is developed capable of finding the globally optimal solution for the location of offshore substations (OSSs), sizing of the transmission infrastructure and topological layout. Rather than a single optimal solution, the algorithm finds a solution space of feasible topologies, bounded from below by the optimal radial solution. The algorithm is applied to 4 test cases including one based on the Belgian North Sea area. It is shown to outperform a traditional Transmission Network Expansion Problem (TNEP) formulation both in computational speed and solution quality. [ABSTRACT FROM AUTHOR]

Protecting high-voltage (HV) DC grids requires a different approach compared with that of ac power system protection and poses one of the major challenges that must be resolved before the realization of largescale HVdc grids that use equipment from multiple vendors. HVdc grid protection, which is essential for safe and reliable HVdc grid operation, entails the appropriate detection and fault clearing of dc-side short circuit faults (i.e., dc faults). In this context, fault clearing refers to interrupting the dc fault current and isolating the faulted component. [ABSTRACT FROM AUTHOR]

Given the high interruption costs of industrial processes, dependent on the cause, duration, and time, accurate availability assessment of the industrial energy systems (IES) supplying those processes is crucial in order to avoid unnecessary investments or indicate necessary improvements. A method is presented to sectionalize an IES based on its radial topology and recoverability options. Additionally, this paper introduces a novel nonrenewal stochastic process able to compute the (un)availability of single-feeder sections with respect to cause, duration, and time, taking into account competing risks, general transition rates, and both minimal and perfect corrective maintenance. An accompanying solution strategy is developed, which allows decoupling of the very diverse time constants. Finally, a numerical illustration is provided validating the proposed approach against the Markov and semi-Markov processes under their respective assumptions and illustrating the possible errors when modeling the problem using the aforementioned stochastic processes. [ABSTRACT FROM AUTHOR]

This paper proposes a new \boldsymbol n -port hybrid dc circuit breaker for offshore multiterminal HVDC grid application. The \boldsymbol n-port dc circuit breaker can substitute \boldsymbol n-1 hybrid dc circuit breakers at a dc bus with \boldsymbol n-1 adjacent dc transmission lines. The system-level behavior of the proposed multiport hybrid dc circuit breaker is similar to other hybrid dc circuit breakers. The operation principles of the proposed multiport dc circuit breaker are introduced, analyzed, and compared to the existing solution in this work. The components ratings are compared to the existing solution, and the functionality of the proposed device is verified by simulation. [ABSTRACT FROM PUBLISHER]

This paper develops a long term transmission expansion optimization methodology taking the probabilistic nature of generation and demand, spatial aspects of transmission investments and different technologies into account. The developed methodology delivers a stepwise investment plan to achieve the optimal grid expansion for additional transmission capacity between different zones. In this paper, the optimization methodology is applied to the Spanish and French transmission systems for long term optimization of investments in interconnection capacity. [ABSTRACT FROM PUBLISHER]

This work develops a hybrid optimization method for determining optimal radial transmission topologies for the connection of offshore wind farms combining Association Rule Mining (ARM) and a greedy algorithm. The method is capable of optimally placing offshore substations and accounts for Capital Expenditures (CAPEX), Corrective Maintenance (CM), losses and Expected Energy Not Transmitted (EENT). The stochastic nature of wind is also considered. First, an inequality based apriori algorithm is applied to a randomly generated population of Offshore Wind Power Plant (OWPP) pairs within a specified search domain. This way, a set of simple constraints is obtained reducing the effective combinatorial search space. A verified optimal greedy algorithm is then applied to efficiently search the reduced search space for the lowest cost radial topology to connect offshore wind. The hybrid approach is shown to introduce minimal error given a sufficient sample population while greatly extending the feasible problem size of the greedy search algorithm. • An original hybrid algorithm for offshore wind transmission topology optimization. • Association rule mining is applied as a clustering strategy. • Generation of synthetic data for machine learning analysis in offshore wind optimization. • Results show increased tractable problem size while maintaining solution quality. [ABSTRACT FROM AUTHOR]

This paper presents a method to optimize equipment investments in multizonal transmission systems, considering spatial properties of the areas of focus. Together with a probabilistic technique for assessing nodal injection capability, the method in the paper completes the methodology of a long term transmission system planning tool. Transmission topology, line route and technology are optimized through iterative application of linear integer programming and Dijkstra's shortest path algorithm. By optimizing the transmission route, the spatial properties of the area of focus are taken into account, which in turn can significantly influence the installation costs of transmission equipment. The optimization method considers both AC and DC technology and takes the N-1 security criterion into account. [ABSTRACT FROM PUBLISHER]

A method to determine the optimal transmission system topology for multiple offshore wind farms is introduced using a rule-based generic algorithm. The methodology is implemented as a software tool determining the best economical and technically feasible offshore transmission solution. The optimization algorithm takes radial, ring shaped, and meshed transmission topologies into consideration. Besides the investments for the offshore grid also new connections or reinforcements in the existing onshore grid are proposed by the algorithm. The developed tool delivers a set of transmission system topologies ranked after their life cycle system costs with their corresponding transmission voltage and technology (HVAC or HVDC), the necessary transmission equipment, and its rating. The optimization results are based on publicly available data. The achieved results are compared with other studies and validated. The developed tool can be used in the planning phase as a guidance for offshore developers with investment decisions and for long-term offshore grid planning, e.g., towards an offshore supergrid. [ABSTRACT FROM PUBLISHER]