To enable local energy trading in the distribution network, a market operator and a system operator are required. The market operator is in a character of business model and responsible for market clearing. The system operator supervises the network in order to operate according to market clearing results. In this paper, the function of the system operator is focused. Since, the market participants bid the price and the quantity of power based on their benefit, a challenge for the system operator is how to manage if there is a congestion problem. For this purpose, a bus transfer factor is developed. It is a factor that reflects the change of power in the line compared to the change of generation power in the bus. This factor can use as a sharing factor for increasing or decreasing the generation power of market participants. To validate the bus transfer factor method, the study case is provided. A comparative result between the proposed method and the load curtailment method shows that the proposed method can solve the congestion problem with the minimum adjustment.