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together. When the auto-tap calculation feature is used, the relay will give an error message if the spread
ratio is greater than ten.
If one of the calculated taps is outside the acceptable range (2.0 to 20 for 5 ampere units or 0.4 to 4.0 for
1 ampere units), the auto-tap calculation feature will select the nearest acceptable tap and calculate the
other tap (two at a time) so that the correct spread ratio is maintained. If the user is manually calculating
the taps, the same adjustment should be made.
BESTCOMS can be used to provide auto tap calculation by filling in the appropriate fields on the
Percentage Differential
screen (Figure 4-12) and pressing the calculate button or manual tap values can
be entered. Also, the auto-tap calculation settings can be entered for each setting group from the optional
HMI using Screen 5.#.1.2, \PROT\SG#\87\MVA. The manual tap compensation settings can be entered
for each setting group from the optional HMI using Screen 5.#.1.3, \PROT\SG#\87\TAP. These two
screens are mutually exclusive. If the user enters settings on the
TAP
Screen, the MVA and KV settings
on the MVA Screen will be zeroed out. If the user enters settings on the
MVA
Screen, the automatically
calculated taps are shown on both screens.
The auto-tap calculation settings or the manual tap settings can be entered for each setting group with
BESTCOMS or from the ASCII command interface using the S<g>-TAP87 command.
NOTE to users of the BE1-87T Transformer Differential Relay:
Three-phase versions of the BE1-87T also allow internal phase compensation.
The jumper settings for the BE1-87T correspond to the internal compensation for
the BE1-CDS240 as follows:
1 = DAC and
2 = DAB.
When calculating the tap adjust settings for the BE1-87T, the
3 COMPn factor
has to be included regardless of whether phase compensation is done by
connecting the CTs in delta or by using internal delta compensation. The BE1-
CDS240 automatically takes the
3 factor into account prior to the tap adjustment
when internal phase compensation is applied to a set of CT input currents. Thus,
the tap adjust factors for these two relays will not be the same in applications
using internal phase compensation.
Figure 4-12. Percentage Differential Screen, 87 Phase Tab
4-14
BE1-CDS240 Protection and Control
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 ...
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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 ...
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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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