Simulation-based optimisation of LCC-HVDC controller parameters using surrogate model solvers

This paper proposes the use of surrogate model optimisation methods to solve box constrained LCC-HVDC controller tuning problems. The tuning problem is the selection of the proportional-integral controller gains and voltage-dependant current order limiter parameters of an LCC-HVDC link subject to two operational scenarios and a set of large-signal disturbances. The solvers using recently proposed surrogate model methods performed either similarly to or significantly better than solvers using mature methods of the types found in PSCAD/EMTDC, thus confirming the suitability of these surrogate model solvers for simulation-based optimisation of LCC-HVDC controllers

Independent-phase current control of a three-phase VSC under unbalanced operating conditions

This study presents an independent phase-current-control architecture for a three-phase voltage source converter. It comprises three independent single-phase phase locked loops (PLLs), and a dual-loop scheme including an outer loop (responsible for active power and ac voltage control) and three similar inner current control loops. To obtain reliable phase-tracking, an enhanced second-order generalised integrator-based PLL is developed. The phase-tracking angle is strategically selected from the three PLLs to minimise the impact of imbalance-induced distortions. To validate the proposed control scheme, extensive simulations are conducted for a 101-level, 500-MW, 500-kV (dc) half-bridge modular multi-level converter in PSCAD/EMTDC. The simulation results prove that the proposed scheme enables the system to ride through unbalanced conditions effectively and reliably

Modular Dynamic Phasor Modeling and Simulation of Renewable Integrated Power Systems

This paper presents a dynamic-phasor-based, average-value modeling method for power systems with extensive converter-tied subsystems. In the proposed approach, the overall system model is constructed using modular functions, interfacing both conventional and converter-tied resources. Model validation is performed against detailed Electro-Magnetic Transient (EMT) simulations. The analytical capabilities offered by the proposed modeling method are demonstrated on a modified IEEE 9-bus system. A Graphics Processing Unit (GPU)-based parallel computing approach for the solution of the resulting model is presented and exemplified on a modified IEEE 118-bus system, showing significant improvements in computing efficiency over EMT solvers. A co-simulation approach using a Central Processing Unit (CPU) and a GPU is also presented and exemplified using a modified version of the IEEE 118-bus system, demonstrating the model’s parallelization