The appearance of an increasing number of distributed generation sources in the power system (including mainly renewable energy sources) contributes to overloads of existing high-voltage power lines. It is difficult to say clearly which sources are most responsible for the overload. This article proposes a method for optimal power redistribution of sources connected to the high-voltage power grid. Using the example of the IEEE-118 bus test network, a case of emergency shutdown of one line was considered, which resulted in overload of several others. Using one of the metaheuristic optimisation methods and various methods of maintaining the power balance in the network, the existing overloads were eliminated with minimal power reduction in the Renewable Energy Sources (RES). The proposed methodology will enable operators to manage the operation of the power system more efficiently and effectively. It will also contribute to increasing the security and reliability of the network.