Generation rights trade will change the power flow of the grid as well as losses, and then affect the transmission service costs of the grid. Therefore how to take such influence into account effectively and make the corresponding compensation to power grid are the problems to be solved. Firstly, this paper studies the losses allocation method for the section network. A cross-section grid network is equivalent to a linear circuit. Generators and loads are modelled as current sources and the relationship between current sources and branch losses is then established based on the superposition principle. Based on the first step, the relationship between the quantities of generation rights trade and the variations in losses of the network is established. Moreover, losses allocation can be seen as a cooperative game problem that investigates the allocation of surplus obtained by agents of a coalition through cooperation. The Aumann-Shapley is used to allocate the losses and provide fair and reasonable allocation with good economic coherence. Finally, illustrative numerical results with the IEEE 9-bus test system is presented to prove the validity.