Showing papers by "Juan Carlos Balda published in 2011"

Optimal battery chemistry, capacity selection, charge/discharge schedule, and lifetime of energy storage under time-of-use pricing

Abstract: Energy storage units (ESU) can reduce the cost of purchased electricity under time-of-use (TOU) pricing. To maximize the cost reduction, the chemistries, capacities, and charge/discharge schedules of the batteries used in the ESU must be selected appropriately. The batteries must have sufficient capacities to supply the energy demanded by the charge/discharge profiles and to meet the project lifetime. The ESU responds to a TOU price structure. The ESU output power is limited by the rating of the power electronic interface. The cost of the ESU is assumed to increase linearly with battery capacity. A method using linear optimization is developed that determines the battery chemistries, capacities, and charge/discharge schedules simultaneously. The method shows that the Li-Ion battery chemistry is the most cost effective technology due to its high efficiency and that an 11-year project lifetime is most profitable.

A methodology to coordinate solid-state fault current limiters with conventional protective devices

Abstract: High short-circuit currents can cause equipment failures that conventional protective devices may not avoid Alternatively, solid-state fault current limiters (SSFCL) are designed to limit high levels of short circuit currents, in particular, within quarter cycle However, the SSFCL may cause sensor and protection equipment malfunction; this may lead to mis-coordination and false tripping between existing protective devices, and thus reduce system reliability This paper addresses a methodology to coordinate conventional protective devices and a thyristor-based SSFCL in a distribution system, and analyzes potential coordination issues and effectiveness of the proposed method It also describes an approach to produce SSFCL time-current characteristic curves (TCC) and their use in protection coordination studies Lastly, the analysis includes SSFCL to recloser and SSFCL to fuse coordination cases and includes simulation results of several fault scenarios Lastly, the paper describes