Power Transmission & Distribution

Power Transmission & Distribution (T&D) is the system that carries electrical power from power generation stations to end consumers (homes, industries, offices) safely and efficiently.

1. Power Transmission:- Transmission is the process of transferring bulk electrical energy over long distances from power plants to substations.
   1. Key Features
      • Uses very high voltage (typically 66 kV, 110 kV, 220 kV, 400 kV or higher)
      • High voltage → low current → reduced power loss (I²R losses)
      • Uses overhead lines or underground cables
      • Requires step-up transformers
   2. Purpose
      • Minimize energy loss
      • Carry power efficiently across cities and states
   3. Components
      • Transmission towers & conductors
      • Insulators
      • Circuit breakers
      • High-voltage substations
2. Power Distribution:- Distribution is the process of delivering electricity from substations to final consumers.
   1. Key Features
      • Uses lower voltages (33 kV, 11 kV, 415 V, 230 V)
      • Voltage is reduced using step-down transformers
      • Directly supplies power to users
   2. Types of Distribution
      • Primary Distribution – 11 kV or 33 kV
      • Secondary Distribution – 415 V (3-phase) / 230 V (single-phase)
   3. Components
      • Distribution transformers
      • Poles & service lines
      • Switchgear & meters
      • Consumer wiring
3. Transmission vs Distribution (Quick Comparison)

   Feature	Transmission	Distribution
   Voltage Level	Very High	Medium / Low
   Distance	Long	Short
   Consumers	Substations	End Users
   Losses	Very Low	Comparatively Higher
   Transformers	Step-Up	Step-Down

4. Importance of Power T&D
   1. Ensures reliable electricity supply
   2. Reduces energy losses
   3. Maintains voltage stability
   4. Supports industrial & economic growth
5. Simple Flow of Power System:- Power Plant → Step-Up Transformer → Transmission Lines → Substation → Step-Down Transformer → Distribution Lines → Consumer