cpp – Process technology for the chemical industry 02.2020

cpp FOCUS SAFETY AND SECURITY
The protection of power distribution systems is changing
From centralised to
decentralised design
Requirements of process control and design of production facilities has changed
significantly over the past few years. Besides machine uptime and a consistently
high quality of the products to be manufactured, flexibility and data collection
are getting more and more important. This not only changes the design of plants
and systems, but also substantially influences the power supply of the electrical
components.
In the past, chemical plants used to be supplied
by centralised control rooms. The generously
dimensioned rooms offered sufficient
space for all equipment and at the
same time allowed enough cooling capacity
for the components. Temperature rise was
therefore not an issue. This made planning
and extension of systems easy. Large battery
arrays or transformers supplied all components
of the entire plant. Kilometres of
copper wire lines were characteristic for a
24 V(DC) power distribution. The only
problem was the voltage drop on the supply
lines and an effective protection of the various
loads in the field also was a challenge
not to be underestimated.
Relocation to the field
If you look at modern plant construction,
you will notice that the control components
are transferred to the field. This allows a
quicker recording of measuring data and, at
the same time, prompt access to the control
components. This decentralised approach on
the control level then also leads to a decentralised
approach of the 24 V(DC) power
supply – including all associated advantages
and disadvantages.
A major advantage of a decentralised power
distribution is the proximity to the process
and thus significantly shorter cable lengths.
This allows a better control of the production
processes and reduces the required wiring,
saving material costs and installation
time. But as so often in life, there is no light
without shadow. Decentralised control cabinets
offer rather little space, requiring
small, compact and modular devices. In addition,
temperature development of the
components in the control cabinets or distribution
boxes must be considered much
more closely than before. Power loss of the
individual devices and the associated heat
emissions are an essential factor.
Today, many process plants feature a decentralised design on the control level.
Therefore, a decentralised power distribution is very suitable.
Picture: funtap – stock.adobe.com
Individual power distribution systems
Power distribution systems like E-T-A’s
Module 18plus are exactly tailored to the
requirements of decentralised systems in the
process industry. They offer the perfect combination
of modular design and flexibility
for setting up a 24 V(DC) power distribution.
The Module 18plus power distribution
system consists of three modules. The
supply module has push-in terminals which
36 cpp 02-2020