Transmission expansion planning via power flow controlling technologies

• Published in: IET generation, transmission & distribution Vol. 14; no. 17; pp. 3530 - 3538
• Main Authors: Franken, Marco, Barrios, Hans, Schrief, Alexander B, Moser, Albert
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 04.09.2020
• Subjects: AC systems; additional transmission capacities; contingency situations; controllable series impedance; equivalent phase shift; expansion costs; flexible AC transmission systems; higher operational flexibility; integer programming; linear programming; load flow control; mathematical formulations; mixed‐integer linear programming optimisation problem; operating point; optimisation; power flow; power grids; power transmission control; power transmission planning; power transmission reliability; PSTs; renewable energy systems; Research Article; simultaneous placement; synthetic 120 bus system; TCSCs; test system; thyristor applications; thyristor controlled series compensators; transmission expansion planning approach; AC systems; equivalent phase shift; integer programming; higher operational flexibility; mathematical formulations; synthetic 120 bus system; PSTs; linear programming; flexible AC transmission systems; thyristor controlled series compensators; optimisation; power transmission planning; power grids; power transmission reliability; transmission expansion planning approach; power flow; mixed-integer linear programming optimisation problem; operating point; renewable energy systems; contingency situations; TCSCs; power transmission control; simultaneous placement; load flow control; expansion costs; controllable series impedance; additional transmission capacities; thyristor applications; test system
• ISSN: 1751-8687; 1751-8695
• DOI: 10.1049/iet-gtd.2019.1897

The transition from conventional towards renewable energy systems requires additional transmission capacities and higher operational flexibility to overcome contingency situations. This study presents a novel transmission expansion planning approach for the simultaneous placement of AC systems and power flow controlling technologies including high voltage direct current, phase shifting transformers (PSTs) and thyristor controlled series compensators (TCSCs). The approach is formulated as a mixed-integer linear programming optimisation problem and the operating point of power flow controlling devices is endogenously determined by minimising expansion costs. Both PSTs and TCSCs are integrated into the optimisation problem by means of new mathematical formulations. PSTs are presented in more detail considering the PST impedance, which is modelled as an equivalent phase shift. The controllable series impedance of TCSCs is also represented as an equivalent phase shift. Exemplary results based on a synthetic 120 bus system show a significant potential of PSTs and TCSCs to reduce expansion costs as well as to lower the requirement for new transmission capacities. The simultaneous employment of these technologies reduces the expansion costs within the test system between 18.7 and 32.4% compared to those costs generated by the sole reinforcement by AC systems.