Extensive technique for grid-connected converter power generation maximisation during asymmetrical grid voltages

• Published in: IET renewable power generation 2020-04, Vol.14 (5), p.759-770
• Main Authors: Todorović, Ivan, Isakov, Ivana, Grabić, Stevan
• Format: Article
• Language: English
• Subjects: asymmetrical grid voltages; asymmetrical power production; constant power factor; consumption result; current references calculation; distribution networks; extensive technique; grid operator; grid‐connected converter power generation maximisation; negative current components; overcurrent protection; positive components; power convertors; power factor; power generation control; power grids; power production prioritisation feature; power references; powers; pre‐disturbance level; reactive power; reactive power profiles; references calculation algorithms; short‐circuit faults; Special Issue: Challenges in Future Grid-Interactive Power Converters: Control Strategies, Optimal Operation, and Corrective Actions; unbalanced voltages; virtually any active power profiles; voltage control; voltage profiles
• ISSN: 1752-1416; 1752-1424; 1752-1424
• DOI: 10.1049/iet-rpg.2019.0236

Short-circuit faults and asymmetrical power production and consumption result in the appearance of unbalanced voltages. The change in voltage profiles could result in grid-connected converter's overcurrent protection triggering if power references are kept at the pre-disturbance level. This study provides a framework for current references calculation that can result in virtually any active and reactive power profiles that are within the domain of the converter's physical capabilities. This is accomplished by introducing three references calculation algorithms, which are all based on the same underlying concept. The first algorithm gives the grid operator the option to choose to prioritise the production of either active or reactive power and to curtail the power production only to the extent that converter's current ratings are not surpassed. Simultaneously, the oscillations in one of the powers are managed. The second approach also provides power production prioritisation feature, but here power production is realised through adjustable ratio between positive and negative current components. The third scheme is an enhancement of the previous two schemes and allows for the constant power factor to be produced before and during the disturbances. Distribution network model emulated in the hardware-in-the-loop environment was used for the validation of proposed solutions.