Grid interaction of multi‐VSC systems for renewable energy integration. Issue 5 (26th January 2023)

• Record Type: Journal Article
• Authors: Ahmadloo, Fatemeh; Pirooz Azad, Sahar
• Is Part Of: IET renewable power generation. Volume 17:Issue 5(2023)
• Page Start: 1212
• Page End: 1223
• Publication Date: 2023-01-26
• Subjects: AC–DC power convertors -- controllers -- high‐voltage DC power transmission -- stability; Renewable energy sources -- Periodicals; 333.79405
• DOI: 10.1049/rpg2.12676
• Languages: English
• ISSNs: 1752-1416

Abstract

Abstract: Integration of converter‐interfaced renewable energy sources (RESs) into the power system and the transfer of power from RESs to remote load centres over high‐voltage direct current (HVDC) lines may require connecting multiple voltage‐sourced converters (VSCs) to a common alternating current (AC) system. Because of this connection, control loops of various converters will interact through the AC grid, leading to instability and an undesirable transient response. This paper focuses on the system‐level integration of multi‐VSC systems for the integration of RESs. μ analysis is used to determine under which control modes the independently stabilized VSCs connected to a common AC system ensure the multi‐VSC system stability. Furthermore, a sufficient criterion is proposed for the design of the converters' outer control loops independently to ensure the stability of the interconnected multi‐VSC system. For cases of severe interactions, where the interconnected multi‐VSC system may become unstable even if individual VSCs are stable, a joint controller design for converters is proposed to stabilize the multi‐VSC system. The interaction analysis indicates that employing AC voltage control mode by all the converters causes the highest interaction level, and having more converters in reactive power control mode reduces the impact of interactions on the interconnected system stability. Abstract : This paper focuses on system‐level integration of multi‐voltage‐sourced converter (VSC) systems for integration of renewable energy sources. A formulation is provided to express the level of interactions among the adjacent converters and to identify the control modes causing the highest interaction level. Furthermore, a sufficient criterion is proposed for an independent design of converters' controllers to stabilize the multi‐VSC system.