SLOA289B May   2020  – September 2021 66AK2H06 , 66AK2H12 , 66AK2H14 , ADS8588H , AMC3301 , ISO224 , ISO7740 , ISO7741 , ISO7742 , LMZ30604 , SN65LVDS047 , SN65LVDS048A , UCC12040 , UCC12050

 

  1.   Trademarks
  2. 1HVDC Power Transmission Overview and Architecture
    1. 1.1 Electrical Power - Generation, Transmission and Distribution
    2. 1.2 HVAC to HVDC Power Transmission
      1. 1.2.1 Comparison of HVDC and HVAC
      2. 1.2.2 Primary Objectives of HVDC Transmission
    3. 1.3 Working Principle of HVDC Transmission Station
    4. 1.4 Advantages of HVDC Transmission
  3. 2HVDC Transmission System (HVDC station)
    1. 2.1 HVDC Transmission Technologies
    2. 2.2 HVDC Transmission System (HVDC station) Key Components
      1. 2.2.1 Converter
      2. 2.2.2 Converter Valve Arms
        1. 2.2.2.1 Converter Phase Arms
      3. 2.2.3 Converter Transformers
      4. 2.2.4 Power Transmission Lines
      5. 2.2.5 Components for Ripple Control, Harmonic Control and Waveform Shaping
      6. 2.2.6 Protection Equipment
  4. 3HVDC transmission station - Control and Protection (C and P)
    1. 3.1 Control OF HVDC Transmission Station
      1. 3.1.1 System Control
      2. 3.1.2 Master Control
      3. 3.1.3 Station Control
      4. 3.1.4 Pole or Converter Control
      5. 3.1.5 Valve Base Control VBC (valve unit control)
    2. 3.2 HVDC Transmission Station Protection
      1. 3.2.1 Protection of AC Section of HVDC Station
      2. 3.2.2 Protection of DC Section of HVDC Station
      3. 3.2.3 Equipment Protection and Monitoring
      4. 3.2.4 Sampling and DC Fault Detection
    3. 3.3 Fault Recording and Monitoring
    4. 3.4 Control and Protection Panel
    5. 3.5 Diagnostics and Monitoring
  5. 4HVDC Transmission Control and Protection – System Level Block Diagram
  6. 5TI Solutions for HVDC Transmission Station Control and Protection
    1. 5.1 TI Products
      1. 5.1.1 Analog
      2. 5.1.2 Embedded Processing
      3. 5.1.3 Power Supply and Gate Drivers
      4. 5.1.4 High-Speed On-Board Interface and External Communication
      5. 5.1.5 Board Level Isolation and Protection
  7. 6Summary
  8. 7TI Reference Designs
  9. 8Additional References
  10. 9Revision History

2.2.3 Converter Transformers

The converter transformers transform the voltage of the AC busbar to the required entry voltage of the converter. The transformer is an interface between AC side and DC side. The main insulation, therefore, is stressed by both the AC voltage and the DC voltage potential between valve-side winding and ground. These are special types of transformers that are designed to withstand high harmonics currents and voltage stress. Also, they will have tap changers to enable the optimization of HVDC operations. Converter transformers act as galvanic barrier between AC and DC systems to prevent DC potential entering into the AC system. Availability of the HVDC transmission is dependent on the converter transformer performance.

In HVDC transmission there is requirement for large voltage control at the converter & inverter ends. Converter transformer typically includes an on-load tap-changer to assist with voltage regulation. Tapping range is large (25 ~ 30%) with small steps to give necessary adjustments in supply voltage. On-load tap-changers (OLTCs) are used for changing the transformer winding ratio to control the firing angle and to compensate voltage variations. OLTCs are used to control the DC output voltage when the converter is used as rectifier and AC voltage to the grid when the converter is used as an inverter. The transformer tap ratio can be manipulated to help prevent the converter from becoming over or under-modulated. Operating the converter in the over or under-modulated region could have a negative impact on harmonic performance.