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Voltage Sags
Published in Leonard L. Grigsby, and Distribution: The Electric Power Engineering Handbook, 2018
We refer to this distance as the critical distance. Suppose that a piece of equipment trips when the voltage drops below a certain level (the critical voltage). The definition of critical distance is such that each fault within the critical distance will cause the equipment to trip. This concept can be used to estimate the expected number of equipment trips due to voltage sags (Bollen, 1998). The critical distance has been calculated for different voltage levels, using typical fault levels and feeder impedances. The data used and the results obtained are summarized in Table 38.3 for the critical voltage of 50%. Note how the critical distance increases for higher voltage levels. A customer will be exposed to much more kilometers of transmission lines than of distribution feeder. This effect is understood by writing Equation 38.5 as a function of the short-circuit current Iflt at the pcc: (
Atomic-scale investigation of the interaction between coniferyl alcohol and laccase for lignin degradation using molecular dynamics simulations and spectroscopy
Published in Journal of Dispersion Science and Technology, 2019
Yan Wang, Ming Guo, Yilu Zheng, Xiaoxue Zhao, Bing Li, Weiwei Huan
Where K2 is the orientation factor, which could be obtained by the average of random distribution of LAC and CA.[18]Φ is the photon quantum efficiency of tryptophan in the fluorescence spectrum. We have N as the average refractive index of organic matter and water.R0 is the energy transfer efficiency, while E is the critical distance at 50% energy transfer, and J is the integral of the spectral overlap between the LAC fluorescence emission spectrum and the CA UV absorption spectrum, which was obtained from Equation (6):
A closer look at the Debye-Hückel theory and its modification in the SiS model of electrolyte solutions
Published in Molecular Physics, 2020
Dmitri P. Zarubin, Andrey N. Pavlov
Since the oscillation amplitude of decays with increasing r, we can in principle specify a maximum admissible magnitude of ||, , within which the values of are considered negligible, thereby establishing a critical distance beyond which the relation || < consistently holds and the principle of equivalence of spherical charge distributions applies with a sufficient precision. If all the ions in a salt solution were fixed at the distances between them, they would interact with one another according to the DH theory. However, in solution they are in the state of thermal agitation as well as the water molecules are. Because of this we require that the average distance between the pairs of nearest ions, , be much greater than the critical distance so that the probability of finding a pair of ions separated by would be negligible at any instant: Note that is related to the density of charged particles (ions), n, as . This makes it possible to estimate, even though crudely, the highest concentration up to which the DH theory can be expected to apply. (An actual estimation is postponed until the next Section.)