iMCC – High Voltage Disconnect Switch (Isolator) Motorized Control Cabinets:

The Rationale

Most utilities have a large installed base of motor operated disconnect switches (MODs), also called motorized isolators (MI), often thousands of units. Many of these MODs (MIs) need refurbishment (already started at many utilities) or replacement in the coming years as they reach their end of useful life. For a price equivalent to that of the current 40-year-old technology, iMCC allows utilities to equip their disconnects switches with technology that permits:

  • real time monitoring to assure secure and remote operations
  • failure prediction
  • the provision of alarms indicating urgent or timely required maintenance

This monitoring will lead to substantial savings such as:

  • Reduction of load losses
  • Reduction of major equipment failures
  • Reduction of maintenance

Refurbishing or replacing Motor Operators by current, conventional, non-smart grid technology costing an equivalent amount does not achieve the same savings nor the future operating advantages.

EHT can work with the OEMs of disconnect switches to integrate iMCC into their products for purchases of new disconnect switches or isolators.

So utilities now have the opportunity to equip their networks in the coming years with a technology that allows MODs (MIs) to integrate to the “Smart Grid” while providing a better solution to their current MODs (MIs) refurbishment problems.

The Benefits

Globally, large investments in smart grid technology have been made for better security and reliability of electrical grids. High voltage disconnect switches (isolators) have been neglected with respect to innovation and upgrade of design and function until now. EHT International, after five years of research and development has developed iCOD, (intelligent Control Operation Disconnect) and iMCC (intelligent Motorized Control Cabinet). Designed to provide utilities and heavy industrials a level of security for their substations and grids not previously available. High voltage disconnect switches (Isolators) by their very nature are used in part to isolate areas within substations in order that maintenance can be performed, thus they are an integral part in the security and safety of substation personnel.


Old Cabinet



New Cabinet


High Voltage Disconnect Switches

High Voltage Disconnect Switches


Conventional designs have elements that cannot be relied upon should connection to a smart grid be required. One main component that requires much attention of substation personnel is the cam switches found in conventional motorized control cabinets. The cam switches are used to signal the utility and other devices within the substation on the proper opening and closing of the disconnect switch. Over time the cams become loose and they can no longer be trusted. Also, since they can lose their positioning with time, they may not ensure the optimal closed position of the disconnect switch (isolator) itself over time. If the blade is not properly seated within the jaw of the switch, there will be losses and the high voltage disconnect switch (isolator) will overheat. iMCC ensures that the proper position of the blade in the jaw occurs at each closing. If not, an alarm is raised. This positioning system has eliminated the need for cam switches completely.

The optical positioning system provides the added smart grid abilities whereby the user can now trust the signals sent by the controller. Since the iCOD now knows where the arm of the disconnect is at all times throughout manoeuvres, the device can now be truly operated remotely. In many cases, with the conventional technology, crews must be sent to witness openings and closings of disconnects (isolators). This can now be eliminated.

All monitored parameters can be communicated to substation control rooms via many popular communication protocols. Alarms can be triggered remotely or simply by the local display. As more than a year’s worth of operations are stored in the unit, stored data can be used to diagnose incipient faults in the high voltage disconnect switch (isolator).
Therefore, it is reasonable to conclude that including high voltage disconnect switches (isolator) in smart grid deployment would benefit utilities by optimizing their maintenance practices and increasing their grid reliability. It is not justifiable that utility decision makers ignore this piece of equipment in their smart grid strategies. The last major piece of equipment found in substations now has the ability to be controlled more efficiently, monitored in real-time, predict failures and alarm when required. Proper monitoring of the lowly disconnect switch in the end will save millions of revenue dollars. The savings will come in the form of less maintenance required, less load losses due to overheating, predictive maintenance instead of preventive maintenance, catastrophic failure prevention and less human intervention.

High Voltage Disconnect Switches