KTPN series general purpose complete transformer substations with capacity from 25 to 400 kVA represents single transformer substations for outdoor placing. They serve for receiving three-phase AC electricity of frequency 50 Hz and voltage 6 (10) kV, converting it into electricity energy capacity 0,4 kV and supplying it to customers. Substations are intended for agricultural customers’, separate inhabited localities and small industrial facilities in the regions with temperate climate (from -45°C to +45°C) energy supplying. Substation high-voltage input – overhead or cable. On output feeders automatic breakers are mounted. The substation is placed on the elementary concrete platform or on concrete blocks. KTPN series complete transformer substation functional scheme is given on Picture 1. The substation provides active and reactive energy registration. By appointment in the order the counters of any modifications can be installed. There is outdoor lighting feeder in the substation which is equipped with automatic and manual switching on-off device.