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2.1.1.2
Results for testing 87BD with 2 current sources
87BD I
87BD 1
NITIAL
S
S
ETTING
LOPE
0.10
0.10
0.20
0.20
0.30
0.30
0.40
0.40
0.50
0.50
0.50
0.60
0.50
0.70
Selected Settings
Phase A Pickup
Phase B Pickup
Phase C Pickup
Differential Highset can be tested by single phase secondary current injection. 87HS settings will usually be
higher than the continuous thermal rating of the relay current inputs and equipment or test procedure should be
arranged in such a way that the short term thermal withstand of the relay current inputs is not exceeded during
testing. 50% of relay setting current can be injected into each of the 2 winding inputs simultaneously to achieve a
differential current level of 100% if test current is limited by test equipment capacity.
The settings used for Secondary Injection test purposes should be:
W1 ICT Multiplier
W1 ICT Connection
W2 ICT Multiplier
W2 ICT Connection
These settings ensure a 1:1 ratio between the injected current and the relay setting. Note that operation of the
element can be achieved at a lower level of current if a higher ICT multiplier setting is applied.
During testing the Operate current can be monitored on the relay in the Instruments menu.
©2010 Siemens Protection Devices Limited
7SR242 Duobias Commissioning & Maintenance Guide
B
ST
IAS
S
ETTING
0.00
1.00
W2 Current (x I
0.1
1.11
0.2
1.22
0.3
1.35
0.4
1.5
0.5
1.67
0.5
1.86
0.5
2.08
Test Results
0.00
1.00
2.1.1.3
Differential Highset 87HS
1x
Yy0,0deg
1x
Yy0,0deg
W1 C
(
I
)
URRENT
X
N
1.50
2.00
)
n
1.66
2.21
1.83
2.44
2.03
2.71
2.25
3.0
2.5
3.33
2.79
3.71
3.12
4.15
1.50
2.00
Chapter 6 Page 16 of 57
2.50
2.76
3.06
3.38
3.75
4.17
4.64
5.19
2.50
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