Investigation of a new average value based load shedding concept to secure critical infrastructures in case of emergency
The increasing amount of renewable energy sources in distribution and transmission grids demands significant adjustments to secure stability of energy systems (e.g. in cases of emergency with frequency below 49.8Hz). One of the challenges is a high homogenous mixture of load and decentralist generation in the power system so that a selective identification of loads is not possible. This leads to the essential problems for the transmission system operator that if disturbances occur in the grid automatic under frequency load shedding (AUFLS) relays can disconnect renewable plants from the grid rather than of loads which decreases the probability of a successful remedial action. This paper gives an enlightening point of view by using a new load shedding concept in order to address the illustrated challenges. Especially the optimal distribution of relays in the control area according to the 5-step load shedding plan is focused in this investigation.