For example, a pump failure would trigger its safety
valve and then high temperature/high pressure steam burst out, which
melts covering of electrical wires. If the damaged signal lines and
power lines are shorted, both field instruments and control room instruments
would be destroyed. It is matter of course to pay attention to separately
wire power and signal transmission cables in advance, but sometimes
it is simply not possible when you need to squeeze everything in a
limited space.
Field site environment in general is poorer compared from control
rooms because of existence of potential danger by high voltage, high
temperature or high pressure. There are more possibilities of accidents.
An Isolator Unit isolates DC signals which pass through it and can
withstand 2000V AC applied between insulated circuits for 1 minute.
It separates galvanically sensors, transmitters, final control elements
connected directly to field plants from control equipment in control
rooms. This will prevent damage expansion to the control rooms in
case of a plant accident. |
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Can
you tell us how to minimize a destruction of instruments at control room
site caused by a field instrument trouble?
Installing
Isolator Units between the field and control room does minimize such problems.