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5
Installation and Commissioning
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5.5 Electric installation
5.5.1 Basic installation requirements in terms of interference and
EMC
Electronic devices must work correctly at the place of use. This must be applied even if the
device is affected by electromagnetic interference (up to a certain size). The most important
effects of electromagnetic interference, which may affect the device are:
 overvoltage - mainly impulse overvoltage and HF interference induced by
atmospheric disturbances (storms, discharges) and interference from industrial
equipment (frequency converters, compressors, pumps, etc.)
 transients during switching of inductive loads in the network (motors, valves, pumps,
elevators, etc.)
 the difference in voltage potentials between the individual parts of the equipment, the
flow of unwanted balancing currents
 electrostatic discharge
Limitation of the effect of these effects can be achieved by suitable installation, shielding of
electrical and magnetic induction, use of filters in the supply wires to the device, and
interconnection and grounding of metal parts of the installation.
Devices manufactured by ELGAS are designed to have very high immunity to interference.
They are tested according to valid standards (set of standards ČSN EN 61000 4) for
radiation (EMI) and resistance (EMC) to electromagnetic interference in an industrial
environment (see [29], [30], [31]). However, improper installation of the device may reduce
the resistance, especially if the device is connected to other devices (communication,
external power supply, etc.). Therefore, certain principles must be observed when installing
the unit in order not to reduce the immunity to interference.
5.5.2 EMC connection principles
The following principles are a prerequisite for the correct operation of the device (corrector,
recorder).
An example of the correct installation of a converter/recorder in a gas control station
according to the following principles is shown in Fig. 19. The Corrector is connected here
with a telemetry and power supply box (TENAS-01) and is externally powered from the
230Vac electrical distribution network.
5.5.2.1 Surge protection
If an electrical network is used to supply the devices, the TN-S network must be used (i.e.
with a separate middle conductor N and a separate protective conductor PE). When
designing the electrical installation, measures must be taken to reduce the effects of lightning
strikes to a safe level (viz [32] IEC 62305-3, Annex D). The power supply must be protected
against overvoltage in accordance with the set of standards ČSN EN 60099. For the
distribution network, three-stage overvoltage protection is recommended and used as
standard [33] ČSN 332000-5-534 (HD60364-5-534):
NOTICE
When installing the device and connected devices, it is necessary to
follow the standard [10] EN 60079-14.