Remote condition monitor for surge arresters above 1 kV


RAM-1 (Remote Arrester Monitoring) is IoT device intended for wireless monitoring of the condition of gapless surge arresters with continuous operating voltage above 1 kV. Until now, the measurement of the resistive component of surge arresters leakage current in accordance to the standard IEC 60099-5 has been possible only in a HV laboratory. With the innovative measurement system, the resistive component of the leakage current can be measured in accordance to the standard IEC 60099-5 with the same accuracy as in the laboratory. The results of the measurements RAM-1 can wirelessly sent to the buyer’s media of choice or displayed on web and mobile application. RAM-1 is installed on the grounding side of the surge arrester. To monitor a group of arresters installed into a three-phase system it is sufficient to install a single RAM-1 device that is distinguished by:

  • instant alarm in case of fault, autonomous operation, location of fault;
  • versatility to be installed on existing or new gapless surge arresters;
  • simple installation, an affordable solution;
  • up to 20 years without maintenance, no connection fees.
There are already devices on the market that can determine the suitability of surge arresters at the installation site. They operate on different principles:
  1. The simplest are the basic mA meters, which, however, are not capable of displaying only the resistive component of the leakage current, since the leakage current is predominantly capacitive. This is not a relevant measurement.
  2. There are lightning strike (surge) counters. Although these devices can provide some insight into the overvoltage arrester load over its lifetime, they cannot in any way uniquely determine the suitability of the arrester.
  3. Simple disconnecting devices are also installed, which, after destroying the surge arrester, can easily disconnect protected device from network. The disadvantage of disconnecting device is that the distribution system operator does not know that the arrester is disconnected after the operation of the disconnector and that the other devices are not protected anymore.
  4. There are also very advanced devices with very strong electronics support that are capable of performing higher harmonic analysis over the measured signals. These devices can pinpoint the usefulness of a surge arrester, since the third harmonic component is predominantly resistive in nature. The biggest disadvantage of these devices is the extremely high price, which is unacceptable for widespread use.
RAM-1 eliminates all the disadvantages of the above-mentioned devices. RAM-1 is autonomous smart device which will automatically and instantly report status of surge arrester when fault occurs or set values are exceeded.


Usage Surge arresters above 1 kV
Leakage current Resistive component, 0 … 3 mA (± 10%)
Frequency 48 Hz … 62 Hz
Temperature range -20 (-40) °C … + 85 °C
Housing ip protection level IP 67
Standard IEC 60099-5
User interface Mobile and web app, email
Measuring cycle 1 hour
Communication cycle Up to 60 days (customizable)
Communication Bluetooth, 4G/5G or LoRaWAN
Autonomy Up to 20 years, maintenance free
Housing material Termoplastic V-0 (UL 94)
Connector / material Top M12x40, bottom M12x60 / material A2 or A4
Acquired data Surge counter, temperature, inclination, location, leakage current
Installation On: conductor, steel bracket, insulative bracket


Package Without
Basic Extended Full
Resistive component of leakage current IEC 60099:5
Strike counter
Calculation of power loss
Status report every 2 months (email)
Display of last 5 status reports (web)
Display of entire history of status reports (web, app)
Automatic status report when set values are exceeded (email)
Automatic status report when set values are exceeded (web, app, email)
Adjustable status report interval
GPS location (coordinates)
GPS location (coordinates, map, guidance to surge arrester)
Alarm in case of emergency (email)
Alarm in case of emergency (email, web, app)
Additional options
Status report from RAM-1 in the field (Bluetooth)
User Interface – English language
User Interface – on users request
Activity log (routine checks, maintenance, etc.)
User management (limited)
User management (unlimited)
Outsourcing services - management of RAM-1 system by Izoelektro