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Surge Arrester silicone-housed PEXLIM

A flexible silicone-housed arrester family for line discharge class 2 to 5 and system voltage up to 550 kV

PEXLIM is a family of silicone-housed arresters of Hitachi Energy that offer unique advantages by design to offer secure protection against overvoltages. With the silicone directly molded onto the internal components, the design is safe, secure and effective. They permit flexibility in installation and offer great value for money.

PEXLIM arresters are type tested according to IEC 60099-4 and ANSI/IEEE C62.11. Also, complying with customer-specific standards. Applicable to UHV (Ultra High Voltage) applications.


  • Protection of substation equipment 
  • Polluted areas 
  • Compact and angular installation
  • Seismic areas
  • Transformers and reactors
  • Capacitor banks
  • HVDC protection
  • Cables

Why Hitachi Energy?

  • Minimum maintenance cost
  • Customizable mechanical and electrical design
  • Easy to install

Brief performance data

    R-Y  Q-Y P-Z  P-Y 
System voltage  kV  24 - 170 52 - 420 52 - 420  300 - 550 
Rated voltage kV 18 - 144  42 - 396  42 - 396 228 - 444 
Nominal discharge current kApeak 10  10  20  20
Arrester classification IEC 60099-4, Ed.3.0  Station; SL  Station; SM   Station; SH Station; SH 
Arrester classification IEEE Std. C62.11-2012 Station  Station  Station  Station 
Line discharge class Class 2 3 4 4
Mechanical strength (SSL)  Nm 1600 4000 6000 9000

Get to know more

The "open-cage" design adopted by us have one of the highest mechanical strengths of the molded polymer arresters in the market. In the design Hitachi Energy has chosen silicone polymer which is highly hydrophobic and resistant to UV radiation. 

Each arrester is built up of one or more units. Each unit is a polymeric housing containing a single column of ZnO disks, all individually extensively routine-tested during manufacture, dispersed with the necessary spacers as determined by the electrical design for the arrester. 

Long arresters often require (and are supplied with) external grading rings to maintain a uniform and acceptable voltage stress along their length.

Silicone rubber is highly hydrophobic and resistant to UV radiation and has been shown to be the best insulation (compared to both porcelain and other polymers) based on worldwide independent laboratory and field tests. Hitachi Energy uses special fillers to enhance these properties as well as giving it high pollution resistance, tracking resistance and fire-extinguishing features. 

For satisfactory performance, it is important that the arrester units are hermetically sealed. The HTV molding process under vacuum ensures this by efficient bonding between silicone and all internal parts along the entire length. Hence gaskets or sealing rings are not required.

When the arrester is stressed in excess of its design capability the arrester is short-circuited and an internal arc is established. Thanks to the open cage design, the arc burns through the soft silicone material, thereby permitting the resultant gases to escape quickly and directly. At the same time, the aramide fibers keeps all internal parts together and prevent the expulsion of the internal components. Hence, special pressure-relief vents are not required for the PEXLIM design.

The color of the silicon is grey. Seaworthy packing of the arresters is standard.

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