ABB REL 551 2.3 Series Installation And Comissioning Manual page 106


100
Line differential protection (DIFL)
I = I + I
Diff Local Remote
I I
+
Local Remote
I ------------------------------------------ -
=
Bias
2
( ) { [ (
I Max I
=
Bias Bias
Evaluate
The test is performed by injecting a single and a symmetrical three-phase current. If the
optional charging current compensation function is included, the CCComp shall be Off
and no measuring voltage connected to the terminal.
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3URFHGXUH
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The blocking can QRW be done by the COMBITEST test switch. It
has to be made on the station side of the test switch.
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The TestMode is found in the menu under:
7HVW7HVW0RGH2SHUDWLRQ
The 7HVW0RGH command must be saved in order to be activated.
When the protection is equipped with COMBITEST test switch,
the test mode is automatically activated but not saved when the test
handle is inserted.
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VHFWLRQ ³3UHSDUH IRU WHVW´ LQ WKLV FKDSWHU
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This command is found in the menu under:
) ] OR [ ⋅ (
0.5 I
Bias
Own phase
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) ] }
Other phases
&KDSWHU 
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(Equation 5)
(Equation 6)
(Equation 7)