A bipolar hvdc link operates with 300 kv 600 mw at the

Question

Question 1 -

A bipolar HVDC link operates with ± 300 kV, 600 MW (rated voltage & power) at the rectifier end. The resistance of each line conductors is 20 Ohms. The converters transformers have leakage resistance of 0.15 pu on their own base. There are 2 series connected converters per pole. The AC bus voltages at bot rectifier & inverter are regulated at 230kV.

a. Compute the ratings & turns ratio of the converter transformers at both ends.

b. Find the reactive power supplied at the rectifier and inverter stations.

Assume the following operating conditions:  α = γ = 18^o.

Question 2 -

A monopolar HVDC link has one bridge at each terminal. The parameters of the links are as follows:

α_min = 5^o; γ_min = 18^o; R_d = 5 Ohms; R_cr = 10 Ohms; R_ci = 12 Ohms

V_dor = 115 kV; I_ref at the rectifier = 1kA and I_ref at the inverter = 900 A

a. If  V_doir = 117.5 kV; calculate I_d; α;  γ; P & Q

b. Repeat if V_doir = 120 kV.