Abstract
The paper presents the principle of operation of the developed gas protection and oil level control, the purpose of which is to protect power transformers from short circuits. The presented protections are made without using current transformers (CTs) and current relays with ferromagnetic cores, which are widely used in the power industry and have significant weight and size parameters and their high cost. The proposed protections are made with the use of magnetically controlled elements- reed switches. Protections with the use of reed switches can be used at the moment only as a backup to the traditional protections of power transformers, since there is no wide introduction into production of these protections and experience in their operation. At the same time it should be said that such protections are in no way inferior to traditional ones in terms of speed. The presented protections characterize a new approach in the implementation of relay protection and have a resource-saving effect. The resource-saving nature of these protections, applicable to virtually any type and voltage class of power transformers, lies in the use of reed switches, which are, both in cost and in weight and dimensions, an order of magnitude cheaper and smaller in size and weight than the above-mentioned CTs. The proposed protections are made in the form of devices with their installation inside the power transformers, as well as inside their expander tank..