Modelling and Control of an Interline Current Flow Controller for Meshed HVDC Grids

Abstract

Abstract-This article is focused on the modelling and control of an interline Current Flow Controller (CFC) for meshed HVDC grids. The operation states of the CFC are presented and an average model is derived. The average model is used to perform steady-state analysis on a 3-terminal meshed grid, showing the current change capabilities and the benefits on the operation area. The converter control is designed using a linearised model. The system performance of the CFC is tested by means of simulation in a 3-terminal grid and in a 5-terminal grid.

Multi-terminal DC grids: challenges and prospects

“…Although this simple control philosophy could be extended to MTDC grids, this is neither an optimal nor a flexible control solution for modern power systems. Thus, in order to fulfill requirements of tomorrow's networks-with improved performance, reliability, and safety, future MTDC grids need to integrate other devices able to make power flow control flexible [31,32].…”

“…The concept of flexible DC transmission systems (FDCTS) based on using dedicated power converters has been introduced in several works [32] inspired by the successful operation of flexible AC transmission system (FACTS) devices, to provide voltage Considering recent advancements in the field of highpower electronics, the DC/DC converter is a prime candidate to be the first FDCTS device, providing voltage and power control in MTDC grids. By demonstrating success with DC/DC converters, the development of other FDCTS devices can flourish [31].…”

Research on flexible line power control in meshed smart DC distribution systems

“…For flexible power flow in a DC distribution system, the system performance of meshed grid and multiple terminals must be considered. Some multi-terminal HVDC systems have also been studied [23][24][25]. However, the complicated operation modes considering voltages and power directions have not been analyzed in depth and the influence on system performance is not considered.…”

Flexible HVDC transmission systems small signal modelling: A case study on CIGRE Test MT-HVDC grid

“…Moreover, as the power-flow pattern is passively determined by the MT-HVDC configuration and the resistances seen between the HVDC buses [2] there will be a limited room to adjust the power flow pattern by redacting the set-points of power converters. Therefore, flexible power flow control between the buses is a key factor to enable congestion management, loop flow control, addressing power market requests and avoiding transmission bottlenecks [3]. Possible overloading of a HVDC line can lead to its damage and also a possible cascaded failure of the entire system.…”