matlab,simulink,simscape,simpowersystems

Matlab version: R2012a I find the Series RLC Branch block used under Simscape -> SimPowerSystems -> Elements, and the DC Voltage Source block used under Simscape -> Foundation Library -> Electrical Sources. The 2 nodes are both white rectangles. And there is another DC Voltage Source block under Simscape ->...

matlab,simulink,circuit,simscape

If you're allowed and have access to it, the easiest way would be to use Simscape, which has an electrical library. See Simulink Simscape simple circuit not working for a similar question.

simulink,simscape,simpowersystems

I assume you are referring to Simscape/SimPowerSystems. The answer is yes, use the Controlled Voltage Source block from the Electrical Sources library of Simscape or the equivalent Controlled Voltage Source block from the Electrical Sources library of SimPowerSystems (if you use the old generation library of SimPowerSystems, the new one...