ELECTRIC STRENGTH OF ARRESTER FOR LIGHTING SHIELDING OF 6-35 KV TRANSMMCSION LINE WITH LIGHTNING OVERVOLTAGE

The most common device for protection against overvoltages is a valve-type arrester. Due to obsolescence it is proposed to replace valve-type arresters with nonlinear overvoltage limiters or multi-chamber arresters. Modern recommendations for the selection of means for protection against overvoltage take into account not all factors when placing protection devices. For example, when replacing valve arrester with non-linear overvoltage arresters (arrester), accidents often occur. Often, due to the replacement of protective devices, there are violations of the operating conditions of new devices, since in the design of the arresters, they are placed in place of the vale-type arresters. Nonlinear surge arresters have a number of reliability problems, for example, due to frequent single-phase ground faults, thermal instability problems occur. Therefore, as an alternative to arresters in urban distribution networks, it is proposed to use multi-chamber arresters – devices that are a series of discharge chambers in silicone rubber. The purpose of this work is to calculate the electric field strength and conductivity at the exit from the discharge chamber of the multichambe arrestor, study the effect of multichamber dischargers on distribution networks, build up the dependence on the voltage and conductivity of the plasma exhaust gases, depending on the distance to the multichambe arrester

Tris(η5-cyclo­penta­dien­yl)hafnium(III)

In the crystal structure of the title compound, [Hf(C5H5)3], three cyclo­penta­dienyl ligands surround the HfIII atom in a trigonal–planar geometry. The mol­ecule lies on a sixfold inversion axis

(3RS)-S-[1-(3-Chloro­phen­yl)-2-oxopyr­roli­din-3-yl]thio­uronium bromide

In the title molecular salt, C11H13ClN3OS+·Br−, the C—N bond lengths in the –S–C(NH2)2 fragment indicate partial double-bond character of these bonds. The constituent ions are connected by N—H⋯Br bridges into Z-shaped chains. The supra­molecular architecture of the structure can be described by being composed of these chains inter­locked by additional C—H⋯Br short contacts. An intra­molecular N—H⋯O=C bridge, as well as weak C—H⋯O hydrogen bonds, are also present in the structure

3,3′-Dinitro­bis­phenol A

The title compound [systematic name: 2,2′-dinitro-4,4′-(propane-2,2-di­yl)diphenol], C15H14N2O6, crystallizes with two mol­ecules in the asymmetric unit. Both have a trans conformation for their OH groups, and in each, the two aromatic rings are nearly orthogonal, with dihedral angles of 88.30 (3) and 89.62 (2)°. The nitro groups are nearly in the planes of their attached benzene rings, with C—C—N—O torsion angles in the range 1.21 (17)–4.06 (17)°, and they each accept an intra­molecular O—H⋯O hydrogen bond from their adjacent OH groups. One of the OH groups also forms a weak inter­molecular O—H⋯O hydrogen bond