Detailed quantitative comparison of half-bridge modular multilevel converter modelling methods

This paper presents a detailed comparison of different modelling methods of the half-bridge modular multilevel converter (HB-MMC), namely, switching function, Thevenin equivalent and averaged, considering both MMC implementations (large and reduced number of cells). The theoretical basis that underpins each modelling method are discussed. Offline PSCAD simulations are used to validate user-defined switching function and averaged MMC models against the Thevenin equivalent model provided in PSCAD library for accuracy, considering steady-state and dc fault conditions. Furthermore, the RTDS based real-time simulation results of the user-defined HB-MMC switching function model are validated against the above mentioned offline models, considering steady-state and dc short circuit fault operations. Simulation speed and efficiency of different offline HB-MMC models being studied in this paper are compared. From comprehensive corroboration of different HB-MMC models presented in this paper, it has been found that the averaged, switching function and Thevenin equivalent models produce practically identical results during steady-state and dc faults. In detailed offline and real-time simulation studies where fundamental and harmonic dynamics are of interest, switching function model is found to be faster and computational efficient compared to the Thevenin equivalent model

Protection Testing for Multiterminal High-Voltage dc Grid:Procedures and Procedures and Assessment

eAssessment The application of multiterminal (MT), high-voltage dc (HVdc) (MTdc) grid technology requires test procedures for the operation and implementation of the protection solutions. The test procedures are usually derived from experience and from extensive measurement data, which, at present, are still not widely available. Based on a hardware-inthe- loop (HIL) method, advanced dc protection testing strategies, utilizing existing experience for ac grids and requirements for MTdc grids, may overcome this gap

Interoperability of different voltage source converter topologies in HVDC grids

This paper presents a detailed study of DC grid operation using a range of user-defined offline and real-time HVDC converter models which were rigorously validated against offline and real-time benchmarks. Provided that these models are destined for use in real-time hardware in the loop simulation and a wide range of offline system studies, this paper assesses their suitability for studying complex DC grids that consist of multiple voltage source converters which differ in their control range and fault ride-through capabilities. Detailed quantitative studies show that the offline and real-time DC grid models produce well matched results and provide efficient approaches to investigate DC grid operation during normal condition and AC and DC faults

Protection testing for multiterminal high-voltage dc grid : procedures and assessment

The application of multiterminal (MT), high-voltage dc (HVdc) (MTdc) grid technology requires test procedures for the operation and implementation of the protection solutions. The test procedures are usually derived from experience and from extensive measurement data, which, at present, are still not widely available. Based on a hardware-in-the-loop (HIL) method, advanced dc protection testing strategies, utilizing existing experience for ac grids and requirements for MTdc grids, may overcome this gap. This article proposes procedures and guidelines for testing system-level dc protection based on the functionality of MTdc grids for both primary and backup dc protection. Specific performance criteria have been defined, based on multicase testing and statistical analysis, with the considerations of related critical testing parameters for each functional requirement of the dc protection. Accordingly, procedures for a dc protection testing environment and various fault scenarios are defined. The proposed algorithm test procedures will contribute to the standardization of dc protection system design and testing.The European Commission through the Horizon 2020 program and was supported by the EUDP project Voltage Control and Protection for a Grid Toward 100% Power Electronics and Cable Network.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=4154573hj2021Electrical, Electronic and Computer Engineerin

Detailed quantitative comparison of half-bridge modular multilevel converter modelling methods

This paper presents a detailed comparison of different modelling methods of the half-bridge modular multilevel converter (HB-MMC), namely, switching function, Thevenin equivalent, and averaged, considering both MMC implementations (large and reduced number of cells). The theoretical basis that underpins each modelling method are discussed. Offline PSCAD simulations are used to validate user-defined switching function and averaged MMC models against the Thevenin equivalent model provided in PSCAD library for accuracy, considering steady-state and DC fault conditions. Furthermore, the RTDS based real-time simulation results of the user-defined HB-MMC switching function model are validated against the above mentioned offline models, considering steady-state and DC short circuit fault operations. Simulation speed and efficiency of different offline HB-MMC models being studied here are compared. From comprehensive corroboration of different HB-MMC models presented here, it has been found that the averaged, switching function and Thevenin equivalent models produce practically identical results during steady-state and DC faults. In detailed offline and real-time simulation studies where fundamental and harmonic dynamics are of interest, switching function model is found to be faster and computational efficient compared to the Thevenin equivalent model