Electro-Installations, which produce, transform, distribute and consume electrical power are divided into electrical installations with voltages up to 1000 V and over 1000 V, depending on the operating voltage.
The Distributing Device (DD) is the electroinstallation serving for reception and distribution of the electric power and containing:
- modular and connective buses,
- switching devices,
- devices of protection, automatic equipment and telemechanics,
- measuring instruments and accessories.
Distributing devices are subdivided on open (located in the open air) and closed (in the building). In city conditions in most cases there are closed DD.
The substation is the electroinstallation serving for transformation and distribution of electric energy. It consists of DD up and over 1000 V, power transformers or other converters of the electric power and supporting facilities.
The city electrical network includes electroinstallations located in the territory of this city, the serving for power supply of current collectors. These electroinstallations are a set of supply lines from the delivery center (DC), the distributive point (DP) and the transformer substation (TS), distributive lines of 6-10 kV and up to 1000V, input devices for consumers.