An IGBT based series power flow controller for multi-terminal HVDC transmission

Abstract

Increased offshore wind penetration has raised the need of multi-terminal high-voltage direct-current (MTDC) grids. An MTDC system will enable cross-border energy exchange where the excessive energy can be transferred between countries, increasing the functionality and reliability of the network. However, as the number of terminals and branches increases, power flow management becomes a challenge. To improve reliability and efficiency, power flow needs to be rescheduled between terminals. This can be achieved by introducing a power flow controller (PFC). In this paper, an insulated-gate bipolar transistor based series PFC is proposed. A PFC is basically a low power rated controllable voltage source connected in series with a DC line. It enables the regulation of grid power flow via a small series voltage injection. A four-terminal MTDC system is modelled using Simulink/ SimPowerSystems to test the impact of the proposed device. This is analysed under two different control strategies for the voltage source converter-based terminals; namely, masterslave and voltage droop control. Simulation results show that the PFC is capable of enhancing the system performance by suitably redirecting the power flow at the point of connection. Moreover, the results clearly illustrate that the converter control modes effectively affect the power flow in the MTDC grid.

Pole Balancing and Thermal Management in Multiterminal HVdc Grids Using Single H-Bridge-Based Current Flow Controllers

“…Many research activities have taken place in recent years to address power flow regulation in dc grids [6]- [10]. Power flow management through converter control, although essential for the correct dc grid operation, offers limited flexibility and a reduced precision as the grid becomes more complex [11]. Alternatively, power flow can be regulated by auxiliary elements [12], which could be either connected in shunt (i.e.…”

Investigate on a Simplified Multi-Port Interline DC Power Flow Controller and Its Control Strategy

“…This kind of control scheme is simple to implement, but it can only adjust the equivalent resistance of the line in one direction, which limits its power flow control ability. (2) For the DC voltage control type DCPFC, according to the voltage regulation means, it can be further divided into three main types, which are 1 a DC transformer type [6][7][8][9][10], 2 an auxiliary voltage source type [11][12][13][14][15]] and 3 a capacitor-based interline energy-exchanged type [3,[16][17][18][19][20][21][22][23][24]. In comparison, the DCPFC of capacitor-based interline energy-exchanged type has more advantages and better application prospects.…”

Fault mode operation strategies for dual H-bridge current flow controller in meshed HVDC grid

“…Several variants of CFCs, including modular bidirectional PFC with fault blocking capability [3], switched resistors for power flow control of the short transmission lines, DC/DC converters for long transmission lines [4], floating CFC [5] and thyristor based power flow controllers [6,7] have been proposed in the literature. Furthermore, IGBT based CFCs with the ac grid connection [8], dual H-bridge CFC [9], cascaded and hybrid PFCs [10], double full-bridge DC/DC converters based CFC [11], a multi-port CFC [12] and interline CFC based on coupled inductors [13] have been investigated in recent years.…”