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Voltage limiting device HVL

Voltage limiting device for DC traction systems

Voltage limiting device HVL consists of the parallel connection of a metal-oxide (MO) surge arrester with no spark gaps and two anti-parallel connected thyristors. Transient surges caused by lightning and switching operations in the system are limited by the MO arrester. If surges occur for a longer period of time (milliseconds to hours) due to faults in the system or for operational reasons, the thyristors fire to limit touch voltages. As soon as a zero-current transition occurs, the thyristors cut off the current flow and the original condition is restored. The whole device is molded in silicone, designed and tested according to EN 50122-1 (IEC 62128-1), EN 50123-5 (IEC 61992-5), EN 50526-1 (IEC 62848-1).

Voltage limiting devices are used to prevent impermissible touch voltages in DC traction systems in normal operations and in fault conditions by bonding the return circuit of a DC railway system to the earthing system or to the exposed conductive parts.

Voltage limiting devices are available for nominal triggering voltage 60 V and 120 V.


  • HVL compiles with both VLD-O (normal operation) and VLD-F (fault) functionality in the specified current range

Why Hitachi Energy?

  • Over 100 years of experience in overvoltage protection and more than 30 years with silicone insulation
  • Local and global Hitachi Energy application support
  • Own production of metal-oxide (MO) resistors
  • Mechanically strong design
  • UV resistant  silicone housing with excellent pollution performance
  • Voltage limiting device HVL does not require power supply

Brief performance data

    HVL-60 HVL-120
Normal triggering voltage V 60 120
DC short-time withstand current at 100 ms - recoverable kA 2.1 2.1
DC short-time withstand current at 100 ms - non-recoverable kA 20 20
Discharge current (In) kA 25 25
High current impulse with wave 8/20 µs kA 80 80
High current impulse with wave 10/350 µs As 12 12


For more details see the data sheet in downloads below.

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