Sensorless load monitoring and management in electric power grid through energy harvesting
The article shows a possibility to measure the instant value of the consumed current in electrical devices or in branches of the electric power grid, without specialized sensors. As it is demonstrated, in some types of electrical networks the neutral conductor could be used as a current sensing device and as an energy source. The measuring of the voltage difference between the neutral conductor and the protective conductor can supply convenient information about the load.
Electric Secondary Distribution System Design
As energy prices and the costs of building new generating facilities continue to increase, electric utilities have started looking for ways to reduce system losses. The secondary distribution system is under scrutiny due to the large number of distribution transformers and high secondary load currents. A companion paper (Gibson et al., 2007) presents a new method of secondary distribution system modeling and load characterization. The secondary distribution system is modeled in terms of a few secondary circuit archetypes. The power demand of each load is derived from actual energy consumption. A computer software using Microsoft Excel has been developed to calculate the losses for all transformer secondary circuits in the pilot area, including energy losses in the service drops, secondary lines, and transformers; thus, the circuits with the greatest losses are identified for further study. The applications of the proposed secondary distribution model and load characterization on the economic analysis and design of secondary circuits are also presented.
Modeling of chemical reactors—XXIX mixing-cell model for packed bed reactors. Steady state considerations. Problems of multiplicity
Abstract The axial heat and mass transfer in tubular catalytic reactors may be described by mixing-cell model and diffusion model as well. The diffusion description yields for a strong exothermic reaction and adiabatic conditions three steady state profiles, on the other hand the mixing-cell model gives rise to more than three steady states. A simple numerical and graphical analysis for mixing-cell model is presented.