Abstract
Voltage source converters (VSCs) are self-commutated converters able to generate AC voltages with or without the support of an AC connecting grid. VSCs allow fast control of active and reactive powers in an independent way. VSCs also have black start capability. Their use in high-voltage direct current (HVDC) systems, comparative to the more mature current source converter (CSC)-based HVDC, offers faster active power flow control. In addition, VSCs provide flexible reactive power control, independent at each converter terminal. It is also useful when connecting DC sources to weak AC grids. Steady-state RMS analysis techniques are commonly used for early-stage analysis, for design purposes and for relaying. Sources interfaced through DC/AC or AC/DC/AC converters, opposite to conventional generators, are not well represented by electromotive forces (E) behind impedance models. A methodology to include voltage source converters (VSCs) in conventional RMS short-circuit analysis techniques is advanced in this work. It represents an iterative procedure inside general calculation techniques and can even be used by those with only basic power electronics knowledge. Results are compared to those of the commercial software package PSS®CAPE to demonstrate the validity of the proposed rmsVSC algorithm.
Highlights
Voltage source converters (VSCs) are used to connect high-voltage AC and DC systems.voltage source converter (VSC) maintain DC voltage polarity for their building blocks, as well as for “modules” forming a Modular Multi-Level Converter (MMC)
In VSCs, the direction of the DC current controls the direction of the active power flow (P)
It was assumed that high-voltage direct current (HVDC) networks can fully control the DC voltage, even if no active power can be in the AC grid
Summary
Voltage source converters (VSCs) are used to connect high-voltage AC and DC systems. VSCs maintain DC voltage polarity for their building blocks (for the two-level or three-level converter), as well as for “modules” forming a Modular Multi-Level Converter (MMC). Compared to the more mature current source converters (CSC-HVDC), VSCs offer faster active power flow and independent reactive power controllability, allowing for easy integration in multi-terminal high-voltage DC systems (VSC-based HVDC). VSCs are able to operate even in very low voltage scenarios and can connect to weak or isolated grids [5] They have limited overcurrent capacity, even for extremely low voltage scenarios, an effective contribution to steady state short-circuit currents is expected because of the large VSCHVDC capacity. Fischer and Mendonca [6] performed short-circuit analysis considering Thevenin’s equivalent They assumed wind energy converters (WECs) with full AC/DC/AC VSCs were injecting purely inductive constant currents, and that all the network elements were purely reactive.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
