Short Guide to Surge Protection Device

Posted by Claire Smith on January 14th, 2021

The Surge Protection Device (SPD) is a term used for describing an electrical device that is typically installed in process control systems, power distribution panels, communications systems, and other heavy-duty industrial systems for purpose of protecting against electrical current

In electrical systems, surge protection devices (SPDs) are usually mounted in tap-off configuration (in parallel) between the earth and live conductors. Whereas, the operating principle of SPD is almost similar to that of a circuit breaker.

How to install a surge protection device in a low voltage panel?

There are two conditions for installing a surge protection device

In normal use (no overvoltage): When there’s no overvoltage, then a surge protection device is installed just like an open circuit breaker.

When there is an overvoltage: In this case, the surge protection device becomes active and discharges the lightning current to the earth. It tends to be compared to the end of an electrical switch which would cut off electrical organization with the earth using the equipotential earthing framework and the uncovered conductive parts for a concise moment, restricted to the length of the overvoltage.

Once the overvoltage gets discharged, then circuit breakers open, and SPD automatically returns to its normal state

Common features of the Surge protection device

The surge protection device manufacturers have made this device with some highlighting features that make it vulnerable to use in all-electric systems. These features are;

• UC: It denotes the maximum continuous operating voltage. This refers to A.C. or D.C. voltage above which the SPD gets dynamic. This worth is picked by the appraised voltage and the framework earthing game plan.

• Up: Voltage protection level. This denotes maximum voltage across the SPD terminals when it gets active. This voltage comes when the flowing current in SPD is equal to In. The voltage assurance level picked should be underneath the overvoltage withstand capacity of the heaps.

• In an instance of lightning strokes, the voltage across the terminals of the SPD by and large remaining parts not exactly Up.

• In: Nominal release current, this is the pinnacle estimation of a current of 8/20 µs waveform that the SPD is equipped for releasing at least multiple times.