Method In An Electric Power System, Controller, Computer Programs, Computer Program Products And Electric Power System

The invention relates to a method in an electric power system including one or more power generation source(s) and a dynamic power compensator having a battery energy storage. The method includes the steps of: detecting a frequency disturbance within the electricity power system requiring an additional power generation source to be connected to the electricity power system in order to meet a power demand; and controlling the power output from the battery energy storage of the dynamic power compensator during start-up of the additional power generation source thereby limiting the frequency disturbance within the electric power system. The invention also relates to a controller, computer program, computer program products and electric power system.