Insulation; Signal Inputs; Automatic Voltage Control - Siemens 7sg15 microtapp Operation Manual

6.1 Insulation

For a new installation the wiring insulation should be tested: -
•
Connect together all CT circuits and measure the insulation resistance between these circuits, all other
circuits and earth.
•
Connect together all VT circuits and measure the insulation resistance between these circuits, all other
circuits and earth.
•
Connect together the circuits of the status inputs and measure the insulation resistance between these
circuits, all other circuits and earth.
•
Connect together the circuits of the output relays and measure the insulation resistance between these
circuits, all other circuits and earth.
For satisfactory results the insulation level should be above 1.5 MΩ.

6.2 Signal Inputs

An initial check of all wiring should be made to confirm the correct connections.
6.2.1 MicroTAPP enable and controls
All points of control should be checked, preferably prior to energising the transformer. If this is not possible care
should be exercised when operating the tap change mechanism to prevent abnormal voltages. The checks shown
in Table 1 should be carried out in sequence to confirm the correct operation of the various points of control (in
the order 1A, 1B etc.). The table indicates a typical arrangement of three control points, particular installations
may deviate from this configuration.
Sequence
1
2
3
4
5

6.3 Automatic Voltage Control

Prior to despatch full accuracy, function and endurance testing is carried out to confirm correct operation of the
relay, further on-site accuracy testing is unnecessary. Final checks for operation can be carried out when the
transformer is energised.
©2012 Siemens Protection Devices Limited
Tap Change MicroTAPP
Mechanism
A
Switch to LOCAL
LOCAL/MANUAL
Check Tap change Check control
operation
Switch to REMOTE Check tap change
control and
Switch to REMOTE
Switch to LOCAL
Table 1
7SG15 MicroTAPP Commissioning
Remote
B C
Switch to
Confirm control
Inhibited blocked
Confirm control
blocked
operation
Confirm remote
operation of tap
change control
Chapter 7 Page 4 of 10