I
b2
I
d1
I
d2
I
b3
I
d3
100
200
300
100
200
300
400
500
End section 2
End section 1
Low Trip value
Section 1
Section 2
Section 3
I
d
[%Ir]
I
b
[%Ir]
GUID-EAAB6851-B6A9-4A69-B962-1725A4928D54-ANSI V1 EN
Figure 253:
Operation characteristic for biased operation of 87T
The
Low trip value
of the biased stage of the differential function is determined according
to the operation characteristic:
Low trip value
= Id1
Slope section 2
and
Slope section 3
are determined correspondingly:
Slope section
I
I
d
b
2
100
2
2
=
⋅
%
GUID-D1C2CAED-3D58-4405-A79D-17B203A8D3A9 V4 EN
(Equation 87)
Slope section
I
I
d
b
3
100
3
3
=
⋅
%
GUID-72224800-6EE1-48E7-9B57-4ABE89DB350C V1 EN
(Equation 88)
The second turning point
End section 2
can be set in the range of 100 percent to 500
percent.
The slope of the differential function's operating characteristic curve varies in the different
sections of the range.
•
In section 1, where 0 percent Ir < Ib < End section 1, End section 1 being fixed to 50
percent Ir, the differential current required for tripping is constant. The value of the
differential current is the same as the
Low trip value
selected for the function.
Low trip
1MAC059074-MB A
Section 4
Protection functions
615 series ANSI
511
Technical Manual
Summary of Contents for Relion 615 series
Page 1: ... RELION PROTECTION AND CONTROL 615 series ANSI Technical Manual ...
Page 2: ......
Page 39: ...Section 17 Glossary 1181 Table of contents 615 series ANSI 33 Technical Manual ...
Page 40: ...34 ...
Page 64: ...58 ...
Page 216: ...210 ...
Page 884: ...878 ...
Page 1038: ...1032 ...
Page 1136: ...1130 ...
Page 1172: ...1166 ...
Page 1180: ...1174 ...
Page 1186: ...1180 ...
Page 1192: ...1186 ...
Page 1193: ...1187 ...
Page 1194: ......
Page 1195: ......