7SG15 MicroTAPP Performance Specification
Nt No.
of
transformers
1 to 16 step 1
pf
Initial Assumed System Power Factor
0.85 to 1.0 step 0.01 leading and lagging
2.5 Coupling
The coupling level is entered as the nameplate impedance of the transformer. If the coupling is set other than
zero then the transformers’ taps will not drift apart. Over time the transformers will tend to drift together. At the
correct setting the transformers will minimise circulating current quickly but will not result in hunting.
Coupling
5 to 50% step 0.1%
2.6 Frequency Load Control
The MicroTAPP will act to prevent frequency reduction by voltage reduction if appropriate by predicting the likely
effect. The settings and accuracies are not yet defined.
2.7 Monitoring and Guard Levels
The MicroTAPP will prevent tap-changer runaway and out-of-limit tapping as follows:-
Overcurrent Level
100% to 200% step 1%
Overvoltage Level
95% to 120% step 1%
Undervoltage Level
80% to 105% step 1%
N.P.S. Level
10%
3. Auxiliary energising quantities
3.1 Auxiliary Power Supply
Four versions of power supply will be available.
Nominal Operating
Range
30 V DC
24 to 37.5 V DC
48, 110, V DC
37.5 to 137.5 V DC
220 V DC
175 to 290 V DC
110 V AC
82.5 to 137.5 V AC RMS
1
3.2 Auxiliary Supply Burden
Quiescent
17W
Maximum
20W
©2010 Siemens Protection Devices Limited
Chapter 2 Page 4 of 8
