Excitation protection

Effectively safeguarding electrical generators.

Metrosil exciter discharge resistors are specified in flagship power projects worldwide to prevent damage to excitation systems during shutdown.


High Energy Test Laboratory – confidence built-in.

Our High Energy Test Laboratory (HETL) is rated up to 2,000 Volts, 8,000 Amps and 2 Megajoules – it literally is our very own on-site power station. With such extreme power, HETL is able to put our exciter discharge resistors to the ultimate test – exposing them to the highest level of energy they are ever likely to face.

    • Features

    • Unique design for testing large varistors
    • Rated up to 2,000 Volts, 8,000 Amps and 2 Megajoules
    • Choice of test waveforms (square, voltage controlled;
      square, current controlled; and inductive discharge)
    • High energy test report accompanies all excitation systems
    • Optional true inductive discharge test
    • Benefits

    • Extreme high energy testing capabilities
    • All Metrosil units are tested to maximum voltage, current and energy – assuring proof of performance
    • Enables OEMs to follow recommendations of IEEE 421.6 and DLT 843-2010

Metrosil 8000 Series – the next generation of protection.

The 8000 Series has been developed with direct consultation from leading OEMs and industry experts. It expands on the 6000 Series’ dependability, whilst greatly improving the ergonomics for ease of installation and is future proofed to be compatible with industry developments.

Metrosil 8000 Series features include:

    • Clearly labelled with High Energy Test “pass” badge
    • Protective bar to prevent accidental disc damage
    • Anti-tamper device to ensure unit integrity
    • Ergonomic handles for easy carrying and installation
    • Robust, easy-access connection points
    • Range of standard footprints enables consistent installation
    • Nameplate permanently displaying the unit’s specification details
    • Shipped with certification of high energy testing
    • Every Metrosil unit is extensively tested for optimum performance

Higher energy density 9000 Series – coming soon.

More details of our latest innovation will be released soon.
A patent has been awarded and we are in the latter stages of our rigorous testing protocol.


Metrosil 6000 Series – effectively safeguarding electrical generators.

The Metrosil 6000 Series of non-linear resistors has been specially manufactured for the protection of excitation systems on large electrical generators. The resistors protect large electrical generating equipment, such as hydropower, thermal and nuclear installations, from the damaging effects of powerful high energy surges. Our application engineers can design specific protection arrays for a wide range of energies from joules (J) to mega-joules (MJ) under different voltage and current conditions.

Because Metrosil is a non-linear resistor (using silicon carbide as a semi-conductive material in high energy applications) you can be assured of a faster protection when compared to linear devices. Metrosil de-excitation products are preferred by major OEMs throughout the world – making us the market leaders in SiC excitation discharge. That’s why the biggest hydropower stations in the world use Metrosil for surge protection.


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