Medium Voltage Network
Introduction
Medium electrical voltage is the term used to refer to electrical installations with nominal voltage "Voltage (electricity)") of between 1 and 36 kV.[1].
In fact, they are considered High Voltage installations, and must be treated as such. According to Spanish regulations, medium voltage installations are 3rd category High Voltage installations[2][3].
In some countries, such as Colombia,[4] or Argentina,[5], some with a voltage higher than 36 kV can be considered medium voltage installations.
Uses of medium voltage
Production
Power plant alternators generate electrical energy in a voltage range "Voltage (electricity)") between 10 and 20 kV.
Distribution
In substations, transport or transmission voltages are reduced, normally greater than 132 kV to voltages between 10 and 30 kV. In distribution substations, distribution or distribution voltages are reduced, normally between 36 and 132 kV to voltages between 10 and 30 kV.
Medium voltage distribution lines can be overhead or underground. They usually transport loads of a few dozen megawatts, with intensities that do not usually exceed 400 A. These lines feed company transformation centers (owned by the company responsible for distribution in the area) or clients.
The supports of the overhead lines are usually of medium height, approximately 7 meters, with a single conductor per phase, and up to 4 circuits per support.
Underground lines are usually made of cable with dry insulation or oil-impregnated paper (now obsolete).
Supply of industrial and tertiary customers
Typically, large customers demand high power from the network, which cannot be supplied at low voltage. In these cases, customers contract the supply directly at medium voltage, which feeds one or more transformation centers that they own.