Figure 2.7: Phase-Ground Element Response for a Phase-Ground Forward Fault
Table 2.7: Voltages and Currents for Mho Elements AG, BG, CG, AB, BC, CA
Element
Voltage
Current
Polarization
V
I
VP
AG
VA
IA + K x IR
VA1m
BG
VB
IB + K x IR
VB1m
CG
VC
IC + K x IR
VC1m
AB
VA - VB
IA - IB
-j x VC1m
BC
VB - VC
IB - IC
-j x VA1m
CA
VC - VA
IC - IA
-j x VB1m
m: denotes memory voltage
K = l/3 (ZO/ZL - 1) . . . residual current compensation factor
Torque
T
Tag
Tbg
Tcg
Tab
Tbc
Tca
Each torque is a product with the following form:
In a microprocessor implementation, the computer calculates the six torque-like products and
tests their signs. Positive products indicate impedances inside the expanded mho circle
characteristics.
Positive-sequence memory voltage polarization provides expansion which maximizes coverage
for high-resistance faults. Memory ensures that all elements operate reliably and securely for
at least as long as the memory quantity lasts.
2-34
Specifications
SEL-221F, -1 Instruction Manual
Date Code 920508
Содержание SEL-221F
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Страница 110: ...Example Event Report 2 4 12 Event Reporting SEL 221F 1 Instruction Manual Date Code 930830 ...
Страница 158: ...SETTINGS SHEET FOR SEL 221F RELAY PAGE 2 OF 6 DATE Date Code 921110 ...
Страница 160: ...SETTINGS SHEET PAGE 4 OF 6 FOR SEL 221F RELAY DATE Date Code 930601 ...
Страница 161: ...SETTINGS SHEET PAGE 5 OF 6 FOR SEL 221F RELAY DATE Date Code 961208 ...
Страница 170: ...Figure 6 2 Horizontal Front and Rear Panel Drawings Date Code 920508 Installation 6 7 SEL 221F 1 Instruction Manual ...
Страница 174: ...Figure 6 8 Dc External Connection Diagram Typical Date Code 920508 Installation SEL 221F 1 Instruction Manual 6 11 ...
Страница 228: ...APPENDICES TABLE OF CONTENTS Parts Placement Diagram Date Code 920508 Table of Contents SEL 221F 1 Instruction Manual i ...
Страница 229: ...SEL 200 Series Relay Main Board Troubleshooting Test Points and Jumper Locations ...