A VSC-based Model for Power Flow Assessment of Multi-terminal VSC-HVDC Transmission Systems

Abstract

This paper puts forward a new practical voltage source converter (VSC) based AC-DC converter model suitable for conducting power flow assessment of multi-terminal VSCbased high-voltage direct current (VSC-MTDC) systems. The model uses an advanced method to handle the operational limits and control modes of VSCs into the power flow formulation. The new model is incorporated into a unified framework encompassing AC and DC power grids and is solved by using the Newton-Raphson method to enable quadratically convergent iterative solutions. The use of complementarity constraints, together with the Fischer-Burmeister function, is proposed to enable the seamless incorporation of operational control modes of VSC and automatic enforcement of any converter' s operational limits that become violated during the iterative solution process. Thus, a dedicated process for checking limits is no longer required. Furthermore, all existing relationships between the VSC control laws and their operational limits are considered directly during the solution of the power flow problem. The applicability of the new model is demonstrated with numerical examples using various multi-terminal AC-DC transmission networks, one of which is a utility-sized power system.

Power Flow Calculation for AC/DC Power Systems with Line-Commutated Converter–Modular Multilevel Converter (LCC-MMC) Hybrid High-Voltage Direct Current (HVDC) Based on the Holomorphic Embedding Method

“…The LCC technology offers advantages such as low losses for long-distance transmission. However, it faces challenges such as commutation failures, harmonics generation, and the need for reactive power compensation and polarity reversal for power flow reversal [5][6][7][8]. On the other hand, VSC technology provides benefits like independent active and reactive power control, improved dynamics, and stable operation without large harmonic filters.…”

Analysis and fault location of single-pole ground fault in LVDC ungrounded system

“…DC power transmission technology based on VSC has become an important choice for people in the construction of longdistance, large-capacity, high-voltage power transmission and urban power grid interconnection due to its good economic and social benefits [1]. At present, there are few studies on the analysis of common single-pole ground faults in DC transmission systems.…”

Two-level VSC real-time simulation modeling method based on controlled source compensation

“…Voltage source converter (VSC) is widely used in AC transmission, flexible DC transmission, and converters for new energy access [1] .Before new energy sources such as wind power are connected to the power system, it is necessary to do hardware-in-the-loop testing on the real-time simulator for its VSC controller [2][3][4] , so the accurate modeling of two-level VSC is of great significance for real-time simulation.…”