On kinetics of reactions in HV circuit breakers after current zero

Abstract

An analysis of six different definitions of the rate of reaction is made and it is shown that some of the definitions are not consistent with the mass action law. Kinetic equations are derived whose solution is the time dependence of the composition of an arbitrary closed gaseous system in an ideal state for a given time dependence of temperature on the assumption that either the time dependence of pressure in or the time dependence of the volume of is given. Results are given of the computation of composition of a system of SF6 dissociation and ionization products at a temperature drop from 12 000 K to room temperature and a comparison is made of the time-dependent composition with equilibrium composition for pressures of 0.1, 0.5, 1 and 2 MPa.

Influence of concentration on the values of recombination and ionization rate coefficients of atoms S and F

“…• y o : the rate coefficient r 60 of the forward reaction of (1) was taken over from [3] r 60 = 3.023 × 10 17 T −1.5 exp(−120230/T ) mol −1 m 3 s −1 and r 61 = r 60 /K 60 , where K 60 is the equilibrium constant of the reaction (1). r 62 = r 60 , as well as in the model described in [4], and r 63 = r 62 /K 62 , where K 62 is the equilibrium constant of the reaction (2). • y b : rate coefficients r 60 -r 63 are determined not from current kinetic concentrations of the species F, S, n e at the time t, but from their equilibrium concentrations at the temperature T = T (t).…”

Comparison of some models of reaction kinetics in HV circuit breakers with SF6after current zero

“…Model C was proposed by the co-author of this paper, Coufal in [7]. Considered in model C are 71 reactions, which are given in [7] together with the values of rate constants and with data sources for the calculation of equilibrium constants.…”

“…Model C was proposed by the co-author of this paper, Coufal in [7]. Considered in model C are 71 reactions, which are given in [7] together with the values of rate constants and with data sources for the calculation of equilibrium constants. All the reactions are reversible and in all reactions the ratio of the direct reaction rate constant and the reverse reaction rate constant equals the equilibrium constant.…”

“…Assumed in model B are 24 reactions given in table 1, 24 reactions from [8] (all the reactions in [8] excepting reactions no 14 and 15), the latter modified in the same way as in [7], and five reactions are given below. The temperature dependence of rate constant r k (T ) of kth reaction in table 1 is approximated by the relation…”

“…which are considered in models B and C and are together with the rate constants given in table 2 in [7], the kinetic composition changes fundamentally, in particular for t > 0.1 ms. Not only does the neutralization of ions take place but the whole course of the SF 4 and SF 5 concentrations changes for t > 0.1 s, their course being similar to that in model C (see figure 3). Incompleteness of the set of reactions is a shortcoming of all the three models.…”