Electrical Power Transmission and Distribution Systems Explained

Power Transmission and Voltage Optimization

Tension is increased for transport to higher values, up to 400kV, using transformers to reduce transmission losses. This influences the design of high-voltage lines, optimizing costs. Standard transport values include 132kV, 220kV, and 380kV.

Key Electrical Definitions

• High Tension: A three-phase alternating current between phases with 1kV or more at 50Hz.
• Rated Voltage: The normal effective voltage between phases used for line operation.
• Higher Voltage: The maximum effective tension between phases that may occur due to defects or large load disconnections.
• High Voltage Usage: Typically 30kV, 45kV, and 66kV.

Distribution Networks and Transformation

The distribution network begins at the transformers and ends at the consumer centers, reducing high-tension power to usable levels.

Transformation Center Functions

These centers lower high or medium voltage to low voltage lines. Supply cases include:

• Case A: Up to 30kV, single supplier.
• Case B: Substation supply available, secondary voltage of 30kV or less.
• Case C: Supplies exceeding 30kV.
• Case D: Transformation center supplied in low voltage (BT).

Network Infrastructure

• Substation: Lowers voltage for distribution lines.
• Distribution Center: Provides power to users in low voltage (BT).
• Network Determination: Based on potential demand and surface area.

Urban Network Types

Urban networks include BT, linear, ring, multiple rings, normal spindle, multiple normal spindle, and supported spindle configurations.

Technical Components and Protection

• Reflection Center: The circuit point arriving at the substation or distribution center.
• Network Extension: Lines leading to a medium voltage transformation center.
• Fuse Sections: Derived off-line via mechanical abatement or extraction.
• Fuse Placement: Located at the first derivative of the line support.
• Aerial-Subterranean Conversion: Includes unipolar fuse sections, three lightning rods (arresters), and terminals converting bare aerial conductors to insulated underground conductors.
• Arresters: Devices that ground currents resulting from atmospheric voltage spikes.
• Switching vs. Sectioning: Load-break switches can break a circuit under load, whereas sectioning switches operate only in a vacuum or with minimal current.