On the Way to the Smart Medium Voltage Cubicle

This audio was created using Microsoft Azure Speech Services

Electronics combined with information and communications technology (ITC) are permeating our everyday life more and more. Cars, planes and phones have them. Refrigerators have them. Even our clothes now have them. If an airplane can operate by electronics safely, efficiently and economically, surely an medium voltage cubicle can, too.
Of course, there are electronics inside an medium voltage cubicle. The protection relay has long migrated to digital technology, with the result that it has extended the scope of its functionality to measurement and control. But the necessary independence of the protection relay – to isolate critical functions – inhibits the development of electronics in the cubicle. And yet, replacing hard wires and mechanical operations in a cubicle with electronics and intelligence would deliver major benefits, as we shall see later.
So here’s my new idea: separate the cubicle into two parts, one housing the protection relay and the other integrating smart functions.


Schneider Electric medium voltage
Schneider Electric medium voltage
The integration of universal, low-power sensors, software, and standard communications protocols to replace mechanical processes and hard wiring can add function, accelerate operations, reduce costs and extend the life of the system. It’s not unlike an airplane’s ‘fly-by-wire’ operation.
One of the most important functions of the electronics is monitoring the health of the cubicle. This means regularly registering the temperature, humidity, connections, insulation, pollution, wear of the individual components, as well as the ambient climate of the installation’s location, to verify that they are in good shape and anticipate any possible failure. This does two things: It extends the lifetime of the cubicle and it allows maintenance to be adapted to the condition of the equipment. This is condition-based maintenance versus time-based maintenance.

The integration of electronics also reduces customer delivery time for the cubicle. Less wiring and more standard electronic components speed up the build process. And because the sensors are universal, there are no longer any last-minute sensor changes (for example, changing a 400 amp sensor for a 600 amp one for a new application).
Traceability is also a big benefit. The data collected by the electronics help with lifecycle management of the different components. This way, a list of all the items is kept showing their exact characteristics and references (and when they were replaced), as well as the maintenance interventions. This is especially important for withdrawable circuit breakers. CB turnover can be tracked with the right information for the right CB.
Then again, there is the possibility of aided operation. Today, cubicle operation can be complex, partly because it contains components from different vendors. With electronics, all operations can be motorized (CB, switch, rack in/out, earth switch, etc.), with predefined sequences for regular maintenance tasks. The operator does not need to be familiar with the inside of the cubicle, but can simply push a button to activate the required operation. And it can be done at a safe distance using wireless communications to a smart phone or tablet. The terminal can even connect the operator to a database to download information about the cubicle’s content and status.
So in essence, the integration of electronics in the cubicle can be more economical, raise efficiency, extend equipment lifetime and enhance safety.

To learn more, read our technical paper on this topic.

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