GE MI-869 Instruction Manual page 13

CHAPTER 1: INTRODUCTION
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
Table 1-1: ANSI Device Numbers and Functions
ANSI Device
12/14
24
27P (2)
32 (2)
37
37P
40
40Q
46
47
49
50BF
50G
50SG
50N (2)
50P (2)
50_2
51G
51N
DESCRIPTION OF THE 869 MOTOR PROTECTION SYSTEM
Description
Over Speed Protection/ Under Speed Protection
Volts Per Hertz
Phase Undervoltage
Directional Power
Undercurrent
Underpower
Loss of Excitation
Reactive Power
Current Unbalance
Voltage Reversal
Thermal Model
Breaker Failure
Ground Instantaneous Overcurrent
Ground Fault
Neutral Instantaneous Overcurrent
Phase Instantaneous Overcurrent
Negative Sequence Instantaneous Overcurrent
Ground Time Overcurrent
Neutral Time Overcurrent
1–3