A parellel distributed constrained supervisory strategy for Load/Frequency control problems in networked multi-area power systems is presented. The aim is at proposing a novel coordination strategy that is more effective with respect to the sequential distributed scheme presented in [1]. The proposed method is able to reconfigure, whenever necessary in response to unexpected load changes and/or faults, the nominal set-point on frequency and generated power to the generators of each area so that viable evolutions arise for the overall power system during transients and a new post-fault sustainable equilibrium is reached. In order to demonstrate the effectiveness of the strategy an example on a four-area power system is presented.