84-42
9424200996
Settings Calculation Examples
BE1-11
m
conductors from both ends of the motor. When this is not possible, another method, percent differential is
used when conductor size prevents the use of flux balance CTs (i.e. motors exceeding 2,500 HP).
Percent differential mode requires a set of CTs on the terminal side and neutral side of the motor. It is
preferred that both sets of CTs are identical. A motor differential connection example is shown in
Figure 84-54. Motor Differential Connection Example
This example uses percent differential mode. The motor must have all six stator leads brought out so that
CTs can be placed on the input and output leads of each stator winding.
The six CTs have matching characteristics, and for smaller operation currents (during running mode),
Restraint Slope 1 % can be less. However, during the starting mode, CT saturation is large. As a security
measure, choose a large Restraint Slope 2 % to avoid false trips during starting.
Set the Minimum Restrained Pickup to 0.1 for maximum differential sensitivity, which provides optimal
motor protection. This setting is in per units of tap. The minimum pickup current sensitivity is calculated in
𝑀𝑀𝑅𝑅𝑠𝑠𝑅𝑅𝐴𝐴𝐹𝐹𝐴𝐴
𝑃𝑃𝑅𝑅𝑠𝑠𝑘𝑘𝐹𝐹𝐴𝐴
𝐶𝐶𝐹𝐹𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑅𝑅
𝑆𝑆𝑠𝑠𝑠𝑠𝐴𝐴𝑅𝑅𝑅𝑅𝑅𝑅𝑜𝑜𝑅𝑅𝑅𝑅𝑠𝑠
=
𝐶𝐶𝐴𝐴𝑃𝑃
∙ 𝑀𝑀𝑅𝑅𝑠𝑠𝑅𝑅𝐴𝐴𝐹𝐹𝐴𝐴
𝑅𝑅𝑠𝑠𝐴𝐴𝑅𝑅𝑠𝑠𝐿𝐿𝑅𝑅𝑠𝑠𝑠𝑠𝐿𝐿
𝑃𝑃𝑅𝑅𝑠𝑠𝑘𝑘𝐹𝐹𝐴𝐴
= 2.0
∙
0.1 = 0.2
𝐴𝐴
Equation 84-35. Minimum Pickup Current Sensitivity
CT Circuit 1 Tap and CT Circuit 2 Tap are shown here, but calculated from the System Parameters,
Sensing Transformers screen (Figure 84-35). With equal CT ratios, the secondary currents through the
BE1-11
m
restraint algorithm for external faults and load are similar, and the operating current is very
small. If the differential CTs do not match, use the TAP settings on the System Parameters, Sensing
Transformers screen to balance the differential.
Running Slope
In running mode, the differential can be more sensitive, yet provide security and reliability at 15 percent
as described by IEEE C37.96-2000,
IEEE Guide for AC Motor Protection
. Set the Restraint Slope 1 %
setting to 15.
Starting Slope
The BE1-11
m
considers the motor to be starting when current is greater than 2
•
FLA in any phase. The
starting mode ends when current in all three phases drops below 2
•
FLA. Therefore, the 2
nd
Slope
Pickup (starting) should be set at the point that restraint current is 2
•
FLA where motor torques and
heating settle quickly to running mode currents (as observed in typical time-current curves). See Equation
M
A
1
I
A
1
•
A
2
I
A
1
A
3
I
B
1
•
A
4
I
B
1
A
5
I
C
1
•
A
6
I
C
1
B
5
I
C
1
•
B
6
I
C
1
B
1
I
A
2
•
B
2
I
A
2
B
3
I
B
2
•
B
4
I
B
2
Remote RTD
Module
BE
1
-
11
m
/
6
Stator RTDs
/
2
Bearing RTDs
/
1
Ambient RTDs
RJ
-
45
RJ
-
45
A
B
C
Summary of Contents for BE1-11m
Page 8: ...vi 9424200996 Revision History BE1 11m...
Page 12: ...x 9424200996 Contents BE1 11m...
Page 21: ...9424200996 1 9 BE1 11m Introduction Figure 1 1 Style Chart...
Page 22: ...1 10 9424200996 Introduction BE1 11m...
Page 40: ...3 6 9424200996 Controls and Indicators BE1 11m Figure 3 3 Front Panel Display Setup Screen...
Page 54: ...5 6 9424200996 Phase Undervoltage 27P Protection BE1 11m...
Page 56: ...6 2 9424200996 Negative Sequence Voltage 47 Protection BE1 11m...
Page 61: ...9424200996 7 5 BE1 11m Phase Overvoltage 59P Protection Figure 7 3 Overvoltage Settings Screen...
Page 62: ...7 6 9424200996 Phase Overvoltage 59P Protection BE1 11m...
Page 68: ...8 6 9424200996 Auxiliary Overvoltage 59X Protection BE1 11m...
Page 80: ...12 4 9424200996 Instantaneous Overcurrent 50 Protection BE1 11m...
Page 84: ...13 4 9424200996 Breaker Failure 50BF Protection BE1 11m...
Page 92: ...14 8 9424200996 Inverse Overcurrent 51 Protection BE1 11m...
Page 105: ...9424200996 18 3 BE1 11m Power Factor 55 Protection Figure 18 2 Power Factor Settings Screen...
Page 106: ...18 4 9424200996 Power Factor 55 Protection BE1 11m...
Page 110: ...19 4 9424200996 Resistance Temperature Detector 49RTD Protection BE1 11m...
Page 118: ...20 8 9424200996 Thermal Curve 49TC Protection BE1 11m...
Page 122: ...22 2 9424200996 Starts per Time Interval 66 Protection BE1 11m...
Page 124: ...23 2 9424200996 Restart Inhibit Protection BE1 11m...
Page 140: ...28 4 9424200996 Breaker Control Switch 101 BE1 11m...
Page 148: ...29 8 9424200996 Setting Groups BE1 11m...
Page 156: ...30 8 9424200996 Metering BE1 11m Figure 30 11 RTD Meter Screen...
Page 158: ...31 2 9424200996 Digital Points BE1 11m Figure 31 2 Digital Points Monitor Screen...
Page 177: ...9424200996 34 5 BE1 11m Motor Reporting Figure 34 9 Learned Motor Data Screen...
Page 178: ...34 6 9424200996 Motor Reporting BE1 11m...
Page 184: ...35 6 9424200996 Alarms BE1 11m...
Page 186: ...36 2 9424200996 Differential Reporting BE1 11m...
Page 196: ...38 4 9424200996 Demands BE1 11m...
Page 198: ...39 2 9424200996 Load Profile BE1 11m...
Page 208: ...41 6 9424200996 Trip Circuit Monitor 52TCM BE1 11m...
Page 212: ...42 4 9424200996 Fuse Loss 60FL BE1 11m...
Page 218: ...43 6 9424200996 BESTnet Plus BE1 11m Figure 43 8 Power Quality Page...
Page 221: ...9424200996 44 3 BE1 11m Mounting Figure 44 3 Case Side Dimensions...
Page 235: ...9424200996 45 5 BE1 11m Terminals and Connectors Figure 45 7 Example of Reversed CT Polarity...
Page 236: ...45 6 9424200996 Terminals and Connectors BE1 11m...
Page 269: ...9424200996 48 15 BE1 11m BESTlogic Plus Figure 48 4 Logic Page 1 for Default Logic...
Page 288: ...49 10 9424200996 Communication BE1 11m Figure 49 14 Modbus Mapping Screen...
Page 306: ...52 4 9424200996 Device Information BE1 11m...
Page 314: ...53 8 9424200996 Configuration BE1 11m Figure 53 3 Display Units Screen...
Page 318: ...54 4 9424200996 Introduction to Testing BE1 11m...
Page 330: ...56 6 9424200996 Commissioning Testing BE1 11m...
Page 336: ...58 4 9424200996 Phase Undervoltage 27P Test BE1 11m...
Page 340: ...59 4 9424200996 Phase Overvoltage 59P Test BE1 11m...
Page 352: ...60 12 9424200996 Auxiliary Overvoltage 59X Test BE1 11m...
Page 360: ...61 8 9424200996 Frequency 81 Test BE1 11m...
Page 364: ...62 4 9424200996 Instantaneous Undercurrent 37 Test BE1 11m...
Page 376: ...63 12 9424200996 Instantaneous Overcurrent 50 Test BE1 11m...
Page 396: ...65 16 9424200996 Inverse Overcurrent 51 Test BE1 11m...
Page 408: ...67 6 9424200996 Power 32 Test BE1 11m...
Page 412: ...68 4 9424200996 Loss of Excitation Reverse Var Based 40Q Test BE1 11m...
Page 426: ...70 10 9424200996 Thermal Curve 49TC Test BE1 11m...
Page 432: ...72 4 9424200996 Starts per Time Interval 66 Test BE1 11m...
Page 436: ...73 4 9424200996 Restart Inhibit Test BE1 11m...
Page 440: ...74 4 9424200996 Virtual Control Switches 43 Test BE1 11m...
Page 450: ...75 10 9424200996 Logic Timers 62 Test BE1 11m...
Page 464: ...79 8 9424200996 Troubleshooting BE1 11m...
Page 480: ...80 16 9424200996 Specifications BE1 11m...
Page 600: ...84 56 9424200996 Settings Calculation Examples BE1 11m Figure 84 70 Logic Page 4 Part 1...
Page 602: ...84 58 9424200996 Settings Calculation Examples BE1 11m...
Page 608: ...85 6 9424200996 BESTCOMSPlus Settings Loader Tool BE1 11m...
Page 609: ......