2. APPLICATION
2-10
DTP-B Digital Transformer Protection
GEK-106243E
2.3.4 PERCENTAGE RESTRAINT SETTING K
2
(FIGURE 9)
The percentage restraint setting K
2
is implemented in DTP-B relays in order to deal with unbalances caused by
saturated CTs due to high currents borne during external faults.
The break point between both slopes K
1
and K
2
must be set to a current value (times the tap) higher than the
forced cooling situation, and lower than the admitted emergency overload level (momentaneous).
The Percentage Restraint Setting K
2
can be set to the same value as K1, or to a higher value, depending on the
previsions of possible CT saturations.
2.3.5 CT CONFIGURATION SETTING
Taking into consideration that the polarity signals P1 are on the busbar side in all windings:
1. A Current Transformer will have
Wye-Wye-Zero
configuration (Yy
∅
) when its secondary terminal S1 is wired
to the
positive terminal
of the corresponding phase in the relay.
2. A Current Transformer will have
Wye-Wye-Six
configuration (Yy6) when its secondary terminal S1 is wired to
the
negative terminal
of the corresponding phase in the relay.
Summary of Contents for DTP-B
Page 23: ...3 OPERATING PRINCIPLES 3 6 DTP B Digital Transformer Protection GEK 106243E ...
Page 53: ...10 INSTALLATION AND MAINTENANCE 10 2 DTP B Digital Transformer Protection GEK 106243E ...
Page 68: ...12 FIGURES GEK 106243E DTP Digital Transformer Protection 12 3 Figure 3 RS 232 Connection ...
Page 69: ...12 FIGURES 12 4 DTP B Digital Transformer Protection GEK 106243E Figure 4 Dimensions Diagram ...
Page 70: ...12 FIGURES GEK 106243E DTP Digital Transformer Protection 12 5 Figure 5 Front View ...