Siemens 7sg15 microtapp Operation Manual page 27

Note that applying Auxiliary Target Voltages, Circulating Current compensation or Frequency compensation will
not adjust the graphical display target voltage. In some cases, therefore, the voltage trace will be outside the band
without Raise or Lower operations being initiated.
When the measured voltage makes an excursion from normal, the central area of the LCD changes to indicate
the progress of the time-out period, see Figure 17. Two indications are given one for 'high' and one for 'low',
normally only one bar is visible.
TRANSFORMER 1
10.9
TAP
CONTROL
If the voltage level is such that it returns within the deadband before completion of the timeout period the timer will
'run back', for a DTL setting the runback rate is equal to the 'run up' rate.
Each out of band timer is independent, if a voltage 'swing through' occurs the display will show both time-outs,
one increasing and one decreasing. The first timer that times-out will initiate a tap change in the appropriate
direction.
When the buttons are operated the labels will change to indicate other functions. If a fault has occurred the 'TEST
LEDS' button is automatically changed to 'RESET' and allows the fault to be cleared.
Operation of the 'Tap Control' button changes the LCD display to that shown in Figure 18 and gives a graphic
display that allows selection of the tap change control to be changed by the 'move' button as required by site
operating conditions, the Figure shows the auto/manual switch selected for operation. The function of the push
buttons is also changed to enable the control switches to be operated.
Only three push buttons can be used when the relay cover is on, the two left most and the right hand button.
These allow selection and operation of the tap change but give read only access to relay setting menus and
stored fault data.
LOWER RAISE
EXIT
In addition, the following warnings can be displayed;
©2013 Siemens Protection Devices Limited
'High' time delay
kV
MENU
'Low' time delay
Figure 17
MANUAL/AUTO
TAP 7
11.2kV
AUTO/
MANUAL
Figure 18
7SG15 MicroTAPP Description of Operation
LOCAL AUTO
07
TAP
TEST LEDS
LOCAL REMOTE
MOVE ->
Chapter 1 Page 25 of 38