Toshiba GRL100-701B Instruction Manual page 256

[Testing of Zone 1 bending characteristic]
The test circuit and test method is same as above.
The operating voltage of Zone 1 bending characteristic can be calculated as follows:
X
0

 
X 1
1
1

= ⋅ =
V X I
p θ

sin

1

where,
X is the Z1S setting reach.
1
θ
is the angle difference between voltage and current.
Note: Toshiba recommend that a minimum of three values for θ be tested to check that the
correct relay settings have been applied.
Care must be taken in choosing values of θ to ensure that the testing points come within
the operating boundary defined by the Z1S θ 2 setting and either the load blinder or mho
settings, as appropriate
(X , R )
1 1
θ
1
θ
2
θ 
tan
 
+
1
θ
tan
1

2 ⋅ ⋅
I
θ
θ

tan sin
+

1
θ
tan

 255 
θ
: Z1Sθ1 setting angle
1
θ
: Z1Sθ2 setting angle
2
R
6 F 2 S 0 8 5 0