A goal programming methodology for multiobjective optimization of distributed energy hubs operation

This paper addresses the problem of optimal energy flow management in multicarrier energy networks in the presence of interconnected energy hubs. The overall problem is here formalized by a nonlinear constrained multiobjective optimization problem and solved by a goal attainment based methodology. The application of this solution approach allows the analyst to identify the optimal operation state of the distributed energy hubs which ensures an effective and reliable operation of the multicarrier energy network in spite of large variations of load demands and energy prices. Simulation results obtained on the 30 bus IEEE test network are presented and discussed in order to demonstrate the significance and the validity of the proposed method

Evaluation of travelling wave based protection schemes for implementation in medium voltage distribution systems

This paper investigates travelling wave based protection schemes developed for high voltage transmission systems and their adaptation to medium voltage distribution networks in order to enable ultra high speed relaying (within a quarter of a cycle of the power frequency) on a medium voltage level. After different travelling wave algorithms are evaluated using simple test systems, they are applied to an industrial power system where fault detection within one millisecond is required. Difficulties that arise from typical characteristics of medium voltage distribution systems are outlined and requirements to measurement and signal processing systems are discussed.</p