7SG15 MicroTAPP Description of Operation
©2013 Siemens Protection Devices Limited
Chapter 1 Page 16 of 38
5.1.2 At the voltage control relay panel
A Local/Remote selector switch on the MicroTAPP, when set to Local, disables control from a remote control
centre. If the tap change is set to Local at the tap change mechanism, Auto/Manual selection can still be altered
and will take effect when the MicroTAPP is enabled.
5.1.3 At a remote site
When the MicroTAPP is set to Remote, controls can be selected and operated from a remote control centre
providing the selector switch at the tap change mechanism is also set to Remote. If not, Auto/Manual selection
can still be altered and will take effect when the MicroTAPP is enabled.
5.2 Control
Switches
The MicroTAPP has integral control switches that can also be operated from a remote control centre, with the
following functions: -
Remote / Local
Auto / Manual
Auto / Manual
Auto Control of
Tap Changer
Manual Raise/Lower from
Comms and/or Status
Inputs
Auto Control of
Tap Changer
Manual Raise/Lower at
Relay fascia
Figure 10
5.2.1 Local/Remote
A switch is provided to allow for the selection of control to be at the relay or from a remote location, normally a
control centre. Remote control is via the communications or status inputs.
5.2.2 Auto/Manual
This switch sets the relay to Automatic or Manual voltage control.
When the MicroTAPP is set to ‘Manual’, the relay will not attempt to correct the voltage automatically. To aid
Manual control, the relay status LEDs show the voltage level in respect of the relay deadband. A digital reading of
the actual voltage level and the tap position is also given.
5.2.3 Raise/Lower
When the Auto/Manual switch is set to Manual this switch allows the tap changer to be operated either to increase
the tap position or reduce the tap position.
The control is operative with the transformer energised or de-energised.