Solving Power Flow Problem of MT-HVDC Grids Compensated by Multiport Interline DC Power Flow Controller

Abstract

DC power flow controllers (DCPFCs) are emerging and promising devices to facilitate power flow in voltage source converter (VSC)-based multi-terminal HVDC (MT-HVDC) grids. In this paper, a novel Newton-Raphson (NR)-based DC power flow solver (DCPFS) is proposed by employing a novel multiport interline DC power flow controller (MIDCPFC) to solve the DC power flow problem (DCPFP) by modifying physical and control state variables of the whole system (MIDCPFC and MT-HVDC grid) simultaneously to obtain the predetermined control objectives. The static model (SM) and power injection model (PIM) of the considered MIDCPFC are derived and their related equations are embedded within the proposed DCPFS. There are no fictitious buses in the proposed DCPFS, the original conductance matrix of the system and its symmetry are preserved, and only minor modifications are needed for the original system Jacobin matrix. The shunt conductance of HVDC lines have also been considered. Furthermore, in the proposed method, the loss of MIDCPFC is modeled for the first time, and the loss of VSCs is considered. Finally, a new 15-bus MT-HVDC grid is proposed for verification purposes. The obtained results verify accuracy and efficacy of the proposed concepts, models and formulations in this study.