Mesophasic properties of S-alkylthiopentonolactones (D-ribono, D-arabinono and D-xylono) and the corresponding itol derivatives with general formula Su-SR (R=n-CnH2n+1) are studied. It was shown that the thermotropic and lyotropic phase transition temperatures are influenced by the following structural parameters: alkyl chain length, free OH group number, cyclic or acyclic Su structure and itol conformation.
Switching of disconnectors in G.I.S. in the presence of an inductive voltage transformer can give rise to extreme conditions which can seriously affect their dielectric withstand capacity. The case is studied in detail. A description of the various overvoltages generated by disconnector operation shows that they can reach 2.3 - 2.5 PU in real G.I.S. configuration. A synthetic test circuit in full...
A.C. voltage tests carried out on various air gaps prove that breakdown parameters vary with test procedure. These variations can be taken into account by using a model, in which A.C. voltage is considered, from a breakdown probability point of view, as a succession of independent cycles. Moreover, switching impulse tests show that one positive half-cycle of A.C. voltage is equivalent to a switching...
A study of the behaviour of a 4 m rod-plane air gap subjected to non-standard waveshapes has been carried out. For this purpose, bumps of different amplitudes and shapes are superimposed on various basic impulses.
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