Telecommunications – PLC System

PLC System

Telecommunication Network of any Power Network provides various Data , Voice and other services utilizing Power Line as Media. This Blog gives us a brief introduction about PLC System, also known as “Power line communication system“.

Power Line Carrier System uses Transmission Line as a Media to provide different services. PLC System uses a High Frequency Signal for its transportation, sharing Transmission Line with Power Signal of 50 Hz (Low Frequency Signal) as per IEC Standard IEC 62488  .

 Telecommunication Services

Power Line Communication provides different services over Transmission Lines beside Voice .

  1. Data Services: Acquisition of Digital and Analogue data from various equipment installed at Power houses and Substations. It covers monitoring and Control of Transformer tap positions, Busbar Voltages along with Megawatt and Megavar values, Breaker and Isolator positions etc. This Data is used by SCADA.
  2. Tele Protection services: Tele Protection Service protects expensive equipment installed at various Power houses and Substations.
  3. Voice Services: Voice Services between Control Center and Power House / Substations.
PLC Layout Drawing

PLC System is a cheaper solution for providing communication solution over Transmission Lines. It is suitable for Radial Power Lines with limited bandwidth requirement. Beside the fact that Power and PLC Signal Travel on same Transmission Lines.


Power lines are used, not only to carry electrical power, but also to transmit communication signals. As a matter of fact it has following key Components.

  • PLC (Power Line carrier): PLC provides Chanel for Data, Tele Protection and Voice Signals.
  • Line Trap: Line Trap blocks high frequency Signal. Most importantly it provides easy path for Power Signal.
  • Coupling Device / LMU (Line Matching Unit) – Outdoor Equipment
  • Coupling Capacitor – Outdoor Equipment
  • DC System – Indoor Equipment used for Power Supply.
  • PAX – Indoor Equipment, used for Voice.

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