Voltage transformers measuring ZNOM-35 and NKF-110
Transformers are large-scale converters and are designed to generate a signal of measuring information for electrical measuring devices, protection and alarm circuits in AC networks with isolated neutral frequency of 50 and 60 Hz. Transformers are manufactured for the needs of the national economy and for export to countries with temperate and tropical climates. Voltage transformers are classified by design (grounded), number of phases (single-phase), type of cooling (oil), rated voltage (27.5 and 35 kV) and climatic design.
Measuring voltage transformers of the NKF and NKF-M series are single-phase, inductive, oil, outdoor installation, in a porcelain cover for inclusion in networks with a rated voltage from 66 to 500 kV. Voltage transformers are made according to a cascade scheme, for voltage class 66, 110 and 132 kV – single – block, for 150, 220 and 330 kV – two-block, and for 400 and 500 kV-three-block. Each transformer unit has its own active part and windings with electrostatic shields. The active part is placed in a porcelain tire filled with transformer oil. The support of the transformer (block) is the base on which the active part and the porcelain tire are mounted. The base has an oil drain device, a secondary terminal box, a cable coupling, earthing bosses and a technical data plate. The magnetic core is made of plates of anisotropic, cold-rolled electrical steel. The design of the windings is cylindrical, multi-layered. The insulation of the voltage transformer is made of insulated transformer paper, dried under vacuum and impregnated with transformer oil. Conductive shields on windings and magnetic circuits improve the stability of voltage transformers against atmospheric shock overvoltages and reduce the level of partial discharges.