APPLICATIONS
RELAY APPLICATION OVERVIEW
Relay Features
The SEL-221F relay provides three zones of forward-reaching phase and ground distance
protection. Independent, internal, user-settable timers delay the Zone 2 phase elements,
Zone 2 ground elements, and Zone 3 elements to provide time-stepped coordination with
downstream relays.
The distance elements are supervised by internal fault detecting phase and ground overcurrent
elements with a wide range of user settable pickup levels.
The distance elements are polarized by positive-sequence memory voltage. Positive-sequence
memory polarization provides expanded resistive coverage for phase and ground faults. The
amount of distance element expansion depends upon the strength of the source relative to the
set relay reach.
Ground distance protection is complemented by an instantaneous directional ground over-
current element and a directional ground time-overcurrent element with four selectable curve
shapes. Both elements have a wide range of pickup settings. The time-overcurrent element
curve shape and time dial settings provide simple coordination with downstream relays. The
ground overcurrent elements may be used together or independently.
The SEL-221F relay includes a single-shot recloser with user selectable initiate and cancel
conditions. The recloser can be supervised using an independent synchronism checking relay,
included in the SEL-221F relay. Also included is a voltage checking function which can be
set to supervise reclosing using live-bus/dead-line, dead-bus/live-line conditions, or either.
The synchronism checking and voltage checking relays can be used to supervise external
closing functions, if necessary.
Relaying potential circuits are typically protected using fuses or molded-case circuit breakers.
Occasionally, one or more of these devices may operate, leaving directional and distance
relays without proper polarizing voltages. In some applications you may wish to detect this
loss-of-potential (LOP) condition and block distance relays or sound an alarm.
The SEL-221F relay includes logic to detect loss of relaying potential, discriminate them from
system faults, and use that information to generate an alarm or block distance and directional
elements. The logic is settable, so that you can choose how the relay uses the LOP detection.
In addition to the features outlined above, the SEL-221F relay adds the following protection
features:
Flexibility for application in communication-based protection schemes such as
POTT, PUTT, DUTT, or DTT. Addition of the communications equipment and a
Date Code 920508
Applications
SEL-221F, -1 Instruction Manual
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Содержание SEL-221F
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Страница 8: ...Time Curve C1 Time Curve C2 Time Curve C3 Time Curve C4 Date Code 961202 SEL 221F Relay Addendum 3 ...
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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 ...