Voltage limiting device HVL

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.

The HVL 120-0.3 limits touch voltages regardless of whether they are purely DC or mixed voltages (both DC and AC voltages) to permissible limit values defined in EN 50122-1.

The HVL 60-0.3 limits touch voltages regardless of whether they are purely DC or mixed voltages (both DC and AC voltages) to permissible limit values defined for workshops and similar locations in EN 50122-1 CI.9.3.2.3.

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

For more details see the data sheet in downloads below.