Consider a HVDC link which uses thyristor based line commutated converters as shown in the figure. For a power flow of 750 MW from system 1 to system 2, the voltages at the two ends, and the current, are given by: V1 = 500 kV, V2 = 485 kV and I = 1.5 kA. If the direction of power flow is to be reversed (that is, from system 2 to system 1) without changing the electrical connections, then which one of the following combinations is feasible?

• A. V1 = -500 kV, V2 = -485 kV and I = 1.5 kA
• B. V1 = -485 kV, V2 = -500 kV and I = 1.5 kA
• C. V1 = 500 kV, V2 = 485 kV and I = -1.5 kA
• D. V1 = -500 kV, V2 = -485 kV and I = -1.5 kA