ISSUES OF IMPLEMENTATION OF AUTOMATIC NON-CONTACT VOLTAGE REGULATION DEVICE ON 6-10/0.4 KV POWER TRANSFORMERS

Abstract

Deviation of voltage values in electrical and power transformers from the values established by international GOST 32144-2013 leads to shortening the service life of electrical receivers and devices, as well as to their rapid failure. Identification of cases of voltage deviations formed in 6-10/0,4 kV power transformers used in the modern power system, introduction of methods for their reduction and improvement of voltage regulation devices to increase the reliability of power transformers in long-term operation and to reduce defects caused by voltage deviations in power transformers are urgent tasks. Several methods and devices are used to eliminate voltage deviations in operating electrical networks.
Especially popular is the method of centrifugal voltage regulation in low-voltage and high-voltage power networks. The introduction of voltage regulation devices in power transformers (centrifugal method) is one of the most effective methods compared to others. Scientific research has revealed a number of disadvantages of mechanical contact voltage regulation devices currently in use. These include the formation of electric arcs in the mechanical contact part during the adjustment process, the burning of transformer oil under the action of the arc and, as a consequence, the reduction of the oil insulation level. In addition, one of the major disadvantages of voltage deviation elimination is that the grid voltage can only be regulated during seasonal periods as a result of using a mechanical contact voltage regulating device such as an NES (non-excitation switching). This paper details the identification of defects of existing voltage regulation devices on power transformers in operation and implementation of automatic contactless voltage regulation device on power transformers. For the scientific study, experimental work was carried out on the developed experimental sample and the results obtained were compared with the values established by the international normative document GOST 32144-2013.