This paper describes a recently developed approach for representing Voltage Source Converter (VSC) bridges using real time electromagnetic transient (EMT) simulators. The fact that such simulators must provide continuous real time response introduces numerous challenges normally not faced in typical offline EMT simulations.
The method presented in this paper utilizes a multiple time step approach in which time critical components are simulated with a small time step (< 2 μsec) while the remainder of the circuit is simulated with more typical time step (~ 50 μsec). The VSC bridge, which can include many valves within a single
lumped circuit is interfaced to the time-domain simulation of the main network.
In an EMT simulation program, the representation of a valve is achieved by the combination of a conductance in parallel with a controlled current source. For the method described in this paper the ON and OFF states of any valve are achieved by modification of the current injection coming from the controlled source rather than changing the conductance value.
T. Maguire, P. Forsyth, R. Kuffel, In Proc. Electrimacs 2005, Hammamet Tunisia, April 2005, Paper No. 210
KEYWORDS: Voltage Source Converter, VSC, electromagnetic transient simulation, real time simulation