HVDC: voltage-sourced converter lines

The VSC DC line model represents two converters, their controls, the line and converter losses, and the equipment ratings.

Model

A VSC DC line joins two converters through the DC resistance RDC. The converter DC powers balance through the line: the power entering the DC side at one converter equals the power leaving at the other plus the \(I^2R\) line loss and the converter losses. One converter regulates the DC voltage and absorbs the balance.

Converter controls

TYPE selects the DC-side control of each converter: 1 holds the DC voltage at DCSET in kV, and 2 holds the active power at DCSET in MW. MODE selects the AC-side control: 1 regulates the AC bus voltage to ACSET in per unit, and 2 holds a fixed power factor of magnitude ACSET. The regulated bus is the converter bus unless VSREG names a remote bus.

Losses

Converter losses comprise a fixed term ALOSS, a term proportional to the converter current BLOSS, and a minimum MINLOSS.

Ratings

SMAX bounds the converter apparent power in MVA. IMAX bounds the AC current in amperes, which corresponds to an apparent-power envelope proportional to the terminal voltage. Reactive output is bounded by [MINQ, MAXQ]. At the solution the converter holds its setpoints, or it operates on a binding rating.