GE 869 Instruction Manual page 13

CHAPTER 1: INTRODUCTION
BUS
Breaker
52
START
Phase CT
50BF 51P
3
Ground CT
50G
1
Differential
core
balance CT
3
RTD
M
Neutral CT
3
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
current and voltage phasors, such that the resulting values have no harmonic
components. RMS (root mean square) values are calculated from one cycle of samples
prior to filtering.
Protection Elements
All voltage, current and frequency protection elements are processed eight times every
cycle to determine if a pickup has occurred or a timer has expired. The voltage and current
protection elements use RMS current/voltage, or the magnitude of the phasor.
Figure 1-1: Single Line Diagram
MONITORING
TRIP
LIGHT
CLOSE
86
AFP
66
50P 50_2 50LR
51G
Core Balance Percent Differential
49S
38
Internal Summation Percent Differential
Table 1-1: ANSI Device Numbers and Functions
ANSI Device
12/14
24
27P
32
37
37P
38
40
40Q
46
47
49
49S
50BF
50G
DESCRIPTION OF THE 869 MOTOR PROTECTION SYSTEM
24
47
32 37 55
67P 49
87S
869
Motor Protection System
Description
Over Speed Protection/ Under Speed Protection
Volts per Hertz
Phase Undervoltage
Directional Power
Undercurrent
Underpower
Bearing RTD Temperature
Loss of Excitation
Reactive Power
Current Unbalance
Phase Reversal
Thermal Model
Stator RTD Temperature
Breaker Failure
Ground Instantaneous Overcurrent
27P 27P 59P 59N VTFF
59_2
67N
51G/N 50G/N
METERING
TRANSIENT RECORDER
EVENT RECORDER
FAULT REPORT
81U 81O 81R
40
40Q
78
892825A4.CDR
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