Page 20 - EngineerIt May 2021

AUTOMATION AND CONTROL

Power protection: Deploying a modular

high-end system with diagnostics

eliminates extensive testing and

operational interruptions

Process engineering plants
must be protected against
surge voltages to avoid
jeopardising their
availability. However, the
surge protection modules
must be checked regularly
and replaced if necessary.
This requires significant
effort if the checks are
carried out manually, and restricts
operation if a signal circuit has to
be switched off for the module to
be replaced. Deploying a modular
high-end system with diagnostics
eliminates extensive testing and
operational interruptions.

urge voltages have many possible causes. Electronics Surge protection with condition monitoring
can receive sustained damage from lightning strikes, The M-LB-5000 surge protection system with condition
Stransients caused by switching operations and load monitoring function monitors signal lines automatically
drops, and interruptions to the supply. There are other effects in and continuously. The patented diagnostics use a special
addition to the direct destruction of components, in particular the algorithm to detect the different load situations that cause
risk posed to plant availability and the resulting consequences the surge protection system to wear. This includes counting
such as production downtime, which drives operating costs up. the number of times the gas discharge tube has ignited,
Surge protection systems must therefore form an integral part of detecting the silicon temperature of the suppressor diodes,
process engineering plants. In addition, current standards such as and measuring the interior temperature of the surge voltage
EN 62305 (SANS 62305) require that the effectiveness of these protection module. When the protection module has reached
systems be checked regularly. Up to now, this check has usually 90 % of its life cycle, this is indicated by a yellow diode.
been carried out manually on-site, which is very costly for large The protection modules are therefore replaced neither too
plants in particular, and requires trained personnel and tools such early nor too late. Replacing them too early leads to an
as a test kit. However, the test results do not give any indications unnecessarily high replacement frequency, while replacing
of prior damage to the protection module and its state of wear. It them too late leads to the plant having phases without
has previously only been possible to rate the tested devices as sufficient surge protection if defective protection modules are
“good” or “bad.” To meet the different safety requirements of the not replaced immediately. This optimises the availability of
signal line market, Pepperl+Fuchs offers two surge protection the surge protection functionality and of the plant, and at the
systems with different functions. same time minimises maintenance costs.

EngineerIT | May 2021 | 18