6-12
BE1-CDS240 Reporting and Alarm Functions
9365200990 Rev F
measured secondary current with phase compensation applied. Tap compensated current (
TAP COMP I
)
is the tap and phase compensated current actually used by the differential function. IOP is the operating
current. SLOPE RATIO is the ratio of
IOP
to the restraint current (maximum
TAP COMP I
). The slope
ratio is compared against the differential alarm setting. To generate a differential report and set the
differential alarm (alarm point number 3), two requirements must be met. One,
IOP
must be above
minimum pickup. Two, the slope ratio must exceed the differential alarm. For example, our settings are
minimum pickup = 0.20, slope = 40%, and differential alarm setting = 75%. Seventy-five percent of the
minimum pickup is 0.75 times 0.2 = 0.15. Operating current must be above 0.15 to satisfy requirement
one. When a differential alarm setting of 75% and a slope ratio setting of 40, requirement two is satisfied
when the slope ratio exceeds 30% (0.75 times 40 = 30%). See the following paragraphs on
Setting
Differential Current Monitoring Alarms
and the associated figure in this section for more information on
slope ratios.
A new differential report will not be generated unless the slope ratio drops below the differential alarm
setting then increases above the setting. Alternatively, a record can be generated using the RA-
DIFF=TRIG ASCII command.
Example 1 is based on the connections of Figure 12-15, an autotransformer with tertiary load. Current
transformers are located in double breakers on the transformer H winding side, a single breaker on the X
winding and on the leads to the Y winding.
Example 1.
>RA-DIFF
CDS240 DIFFERENTIAL CHECK RECORD
STATION ID : SUBSTATION_1
RELAY ID : BE1-CDS240
USER1 ID : USER1_ID
USER2 ID : USER2_ID
RELAY ADDRESS : 0
REPORT DATE : 04/26/03
REPORT TIME : 10:06:50.060
ACTIVE GROUP : 0
PHASE 87 SETTINGS CTR CT CON TX CON GROUNDED ABC SWAP DIFF CKT
CT CKT1 400 WYE WYE YES ABC PRI
CT CKT2 200 WYE WYE YES ABC SEC
CT CKT3 240 WYE DAC NO ABC SEC
CT CKT4 400 WYE WYE YES ABC PRI
MINPU 0.2 * TAP
SLOPE 40 %
ALARM 75 %
URO 6 * TAP
COMPENSATION ANGLE ROTATE ABC SWAP Ground TAP
CT CKT1 DAC NO NO YES
2.00
CT CKT2 DAC NO NO YES
8.00
CT CKT3 WYE NO NO
NO
19.2
CT CKT4 DAC NO NO YES
2.00
ALARMS PHASE A PHASE B PHASE C
DIFFERENTIAL OK OK OK
POLARITY OK OK OK
ANGLE COMP OK OK OK
MISMATCH OK OK OK
MEASUREMENTS PHASE A PHASE B PHASE C
MEASURED PRI I
CT CKT1 167.3 @ 0 167.3 @ 240 167.3 @ 120
CT CKT2 200.8 @ 180 200.8 @ 60 200.8 @ 300
CT CKT3 125.5 @ 151 125.5 @ 31 125.5 @ 271
CT CKT4 54.5 @ 180 54.5 @ 60 54.4 @ 300
Summary of Contents for BE1-CDS240
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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 ...
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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 ...
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