Electrical checks

Functional tests consist in checking the correct functioning

of all the circuits (electrical and electromechanical)

by simulating, as far as possible, the different service

conditions of the assembly.

For example, tests on current and voltage circuits can

be carried out by supplying the secondary circuits of

the CTs and VTs, without disconnecting the CTs from

the circuit.

Electrical checks may include the verification of the proper

operation of circuits and equipment, in particular:

- control, signaling, alarm, trip and reclosing circuits;

- lighting and heating circuits, if present;

- protection and measuring circuits (overcurrent, overvoltage,

earth, residual current trip units, contactors,

ammeters, voltmeters, etc.);

- terminals and contacts available in the terminal box;

- insulation control devices (also creepage distances

and clearances must be verified at level of connections

and adaptations carried out at workshop).

To carry out these checks, in addition to the normal mechanical

tools used for assembling, also some electrical

tools are necessary. A periodical calibration is necessary

to obtain reliable results.

The tools generally used are:

- a tester or multimeter;

- a test bench (AC and DC) to supply the assembly during

the test of the operation under voltage;

- a torque wrench (to check that the correct tightening

torques have been applied to the connections) and

other tools.