Sidebar 13-3. Maximum Restraint Operating Characteristic
Under maximum restraint, the relay will reach the trip or operate point depending on the level of restraint
as shown in the associated figure. When only one current is changed, the restraint current can vary
depending on the relative changes between currents. When one current is decreased from balance, the
maximum restraint has a vertical characteristic. When increasing one current relative to the other, it will
shift to the right with a sloping characteristic as it continues to increase toward the trip region of the
operate characteris c.
ti
1
2
3
4
5
MAXIMUM RESTRAINT CURRENT (IN MULTIPLES OF TAP)
O
PERATING
CURRENT (
IN MUL
T
IPL
ES O
F
TAP)
123
Slop
e
minimum
pickup
increasing current
from balance
decreasing current
from balance
D2857-13.vsd
10-14-99
In order to test the restrained pickup function of the BE1-CDS240 relay, you may increase one of two
currents initially applied in balance, to create an operate imbalance. In this narrative, the Input 1 current
will be the input to be deviated. A similar analysis can be made for deviating Input 2 current.
By increasing input current I
1
from balance, I
1trip
is defined as
I
1trip
= I
1balance
/(1-(
100
slope
)) in per unit
Sidebar 13-3, Equation 1
with the minimum trip point established as
I
1trip min
= I
1balance
+ minpu in per unit
Sidebar 13-3, Equation 2
where minpu is the minimum pickup setting.
13-38
BE1-CDS240 Testing and Maintenance
9365200990 Rev F
Summary of Contents for BE1-CDS240
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Page 8: ...vi BE1 CDS240 Introduction 9365200990 Rev F This page intentionally left blank ...
Page 38: ...1 28 BE1 CDS240 General Information 9365200990 Rev F This page intentionally left blank ...
Page 40: ...ii BE1 CDS240 Quick Start 9365200990 Rev F This page intentionally left blank ...
Page 152: ...ii BE1 CDS240 Metering 9365200990 Rev F This page intentionally left blank ...
Page 226: ...iv BE1 CDS240 Application 9365200990 Rev F This page intentionally left blank ...
Page 286: ...ii BE1 CDS240 Security 9365200990 Rev F This page intentionally left blank ...
Page 290: ...9 4 BE1 CDS240 Security 9365200990 Rev F This page intentionally left blank ...
Page 292: ...ii BE1 CDS240 Human Machine Interface 9365200990 Rev F This page intentionally left blank ...
Page 306: ...10 14 BE1 CDS240 Human Machine Interface 9365200990 Rev F This page intentionally left blank ...
Page 308: ...ii BE1 CDS240 ASCII Command Interface 9365200990 Rev F This page intentionally left blank ...
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Page 349: ...Figure 12 5 Horizontal Rack Mount Front View 9365200990 Rev F BE1 CDS240 Installation 12 5 ...
Page 361: ...Figure 12 17 Typical DC Connection Diagrams 9365200990 Rev F BE1 CDS240 Installation 12 17 ...
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Page 468: ...13 92 BE1 CDS240 Testing and Maintenance 9365200990 Rev F This page intentionally left blank ...
Page 512: ...14 42 BE1 CDS240 BESTCOMS Software 9365200990 Rev F This page intentionally left blank ...
Page 544: ...ii BE1 CDS240 Terminal Communication 9365200990 Rev F This page intentionally left blank ...
Page 550: ...ii BE1 CDS240 Settings Calculations 9365200990 Rev F This page intentionally left blank ...
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