The characteristics of DC power transmission have reciprocal effects on wind farms and it would possibly give rise to the transient overvoltage. The influence of collector parameters on overvoltage level in wind farms cannot be ignored. Under this background, for the modeling problem of wind farm near the DC region, this paper firstly proposes an equivalent modeling method considering power loss of collector networks by combining the power characteristics of transient overvoltage. And then, the effect of collector parameters on the generator terminal overvoltage can be quantified. Finally, the actual grid is included as an example. The characteristics of transient overvoltage and output characteristic of equivalent model are analyzed by simulating the case of two continuous commutation failures of HVDC system. It is shown that the variation of generator terminal voltage in the farend wind turbines is lower than that of the nearend, and the difference is about 2.5% compared to the rated voltage. Therefore, it is necessary to consider the collector parameter equivalence of wind farms. Meanwhile, the power loss and average voltage of this equivalent wind farm model in this paper are fairly remain consistent with that of actual model, so that it has a certain practical application value.