Design Procedure of MMC-HVDC System: Comprehensive Consideration of Internal and External Dynamics

Abstract

This paper proposes a systematic design procedure with comprehensive consideration of the internal and external dynamics in modular multilevel converter high voltage direct current (MMC-HVDC) transmission system. Previous studies on MMC parameter selection separately deal with each specific component such as energy storage capacity for voltage ripple of sub-module (SM) capacitor, arm inductance for second harmonic circulating current reduction, maximum allowable modulation index for MMC operating condition, which considered only a single purpose. However, the parameters respond dynamically to their characteristics and interact directly with the MMC performance, power system conditions, and specific requirements. In this study, we investigate the mutual relationships between the parameters and their performance. Then, we determine the parameter values based on a proposed systematic design procedure with the desired objectives and restricted conditions, which could be cumbersome and time-consuming to approach proper and acceptable parameter values. Therefore, this study could provide engineering evaluations and insights to help MMC-HVDC system engineers and project developers in intuitive approaches regarding the design aspects of the technology requirement challenges. The efficacy and accuracy of the analysis and design method for the MMC-HVDC system parameters were validated by PSCAD/EMTDC time-domain simulation and real-time digital simulation with hardware-in-loop system.

Application Analysis of MMC-HVDC AC Tie Line Transmission in New Energy Power Generation

“…Liu et al is type of converter has to absorb a lot of reactive power and requires a lot of reactive power compensation devices and lters [5]. Kang et al said that the thyristor converter station has a large investment and a large area, and the harmonics generated by the converter have a large capacity and low frequency [6]. Farshad et al said that with the needs of the country's sustainable development and industrialization upgrading, the country will vigorously develop renewable green energy and optimize the energy industry structure [7].…”

Modular Multilevel Converter for Low-Voltage Ride-Through Support in AC Networks

“…R arm was adopted using typical commercial values based on the resistance per length of the wire used in making the MMC arm reactor; for simplicity, this paper adopted the R arm , L arm , and C SM parameters according to Table 4. Furthermore, the selection of L arm and C SM has different objectives such as to reduce the voltage ripple across the submodules' capacitors, suppress the MMC circulating current, and the damping of the fault current rise rate in HVDC systems, as discussed in [24,25]. The MMC application in LVRT support additionally allows the arm impedance parameters' adjustment, submodule capacitance, and the increase of the number of levels, improving the overcurrents' and overvoltages' reduction for a wide range of power levels.…”

Power Quality Compensation Strategy of MMC-UPQC Based on Passive Sliding Mode Control

“…Since the advent of the modular multilevel converter (MMC) [1], it has been increasingly studied and applied in various fields. Specifically, large level numbers and common direct current (DC) side make the MMC very suitable for application in DC transmission [2], [3]. Nowadays, because of its multi-module characteristics, MMC has been used in active filters, and can compensate well for harmonics of current and voltage.…”