GE 745 - P Rotection E Lements

2–6 745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
SPECIFICATIONS CHAPTER 2: OVERVIEW
Accuracy:...........................................................±2.0% of full-scale
LOGIC INPUTS
Number of inputs: ..........................................16
Dry contacts:....................................................1000 Ω maximum ON resistance (32 V DC at 2 mA
provided by the 745)
Wet contacts: ...................................................30 to 300 V DC at 1.5 mA
ANALOG INPUT
Type:.....................................................................DC mA
Ranges:................................................................0 to 1 mA, 0 to 5 mA, 0 to 20 mA, 4 to 20 mA
(programmable)
Input impedance:...........................................375 Ω ±10%
Conversion range:..........................................0 to 21 mA
Accuracy:...........................................................±1% of full scale (based on input range)
TAP POSITION
Type:.....................................................................resistance (ohms)
Range:..................................................................0 to 500 Ω or 0.5 to 5.0 kΩ
Bias current:......................................................1 mA or 10 mA (based on input range)
Accuracy:...........................................................±1% of full scale (based on input range)
RTD
Type:.....................................................................3 wire
RTD Type ............................................................100 Ω Platinum (DIN.43760), 100 Ω Nickel, 120 Ω Nickel
IRIG-B INPUT
Amplitude-modulated:.................................1.0 to 10 V pk-pk
DC shift:...............................................................TTL
Input impedance:...........................................70 to 100 kΩ
2.2.3 Protection Elements
PERCENT DIFFERENTIAL
Operating current pickup: 0.05 to 1.00 × CT in steps of 0.01
Dropout level:...................................................97 to 98% of pickup
Slope 1 range:..................................................15% to 100% in steps of 1
Slope 2 range:..................................................50% to 100% in steps of 1
KP (Slope-1 kneepoint):................................1.0 to 20.0 × CT in steps of 0.1
Harmonic restraint: .......................................0.1 to 65.0% in steps of 0.1
Solid state output operate time:
pickup < 1 × CT: ........................42 to 52 ms
1 × CT < pickup < 1.1 × kneepoint: 34 to 44 ms
pickup > 1.1 × kneepoint:......26 to 36 ms
Relay outputs 2 to 5 operate time:
pickup < 1 × CT:.........................46 to 56 ms
1 × CT < pickup < 1.1 × kneepoint: 38 to 48 ms
pickup > 1.1 × kneepoint:......30 to 40 ms
INSTANTANEOUS DIFFERENTIAL OVERCURRENT
Pickup level:.......................................................3.00 to 20.00 × CT in steps of 0.01
Dropout level:...................................................97 to 98% of pickup
Level accuracy:...............................................per current input