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We have products for custom applications in the electricity sector.

Underground cable sheath currents monitoring system

Within transport lines it is sometimes necessary to locate cables to save parts of line, such as neighbourhoods, rivers, airports, etc. or it is impossible to use overhead lines, as would be the access to the cities of transport lines or, the union within the city of transport substations.

The wire sheat current has a very high dynamic range. So in normal cases of exploitation these currents can be as low as 1 Ampere, being able to get to 150 Amperes for abnormal situations (landslides, theft of earthed connections, short of dischargers, flood, broken sheathings, etc.).

In cases of external or internal cable fault, these currents are typical in short circuit, and it is feasible to have currents next to 10k Amperes or higher values. It is therefore very complex to combine both measures in a single current transformer.


Lumiker has developed an optical current sensor for the integrated management of underground cables.


This sensor would measure the leakage currents associated with the sheats of the power cables. The measure is derived from the current of a conventional current transformer, whose secondary is a coil which concentrates the magnetic field on a garnet which has a high Verdet constant.


This sensor measures the current using a conventional optical fiber. Therefore, it is completely linear and is not subject to saturations. As it is oriented to underground cables, the main measure would be short circuit of it.


It has two transformers on the outer envelope itself. On a same optical fiber it is possible to locate 6 sensors SCM, since each sensor has two current transformers.