Toshiba GRT100 Series, Instruction Manual

Page: 125 / 270


124

6 F 2 S 0 7 8 9
ENTER
key.

Apply an infeed current to terminal TB1-1 and -2.
When the infeed current applied is larger than the setting of ik (pu) and smaller than [kp

p2 +
(1

p1)ik]/(p2

p1) (pu), characteristic DF1 is checked.
When the infeed current applied is larger than [kp

p2 + (1

p1)ik]/(p2

p1) (pu),
characteristic DF2 is checked.
Note: When the default settings are applied, the critical infeed current which
determines DF1 checking or DF2 checking is 1.6×(CT secondary rated
current).

Apply an outflow current of the same magnitude and counterphase with the infeed current, to
terminal TB1-7 and -8.

Decrease the outflow current in magnitude and measure the values at which the element
operates.

Check that the measured values are within 15% of the theoretical values.
For characteristic DF1, the theoretical outflow current is given by the following equation.
I
out
= (1

p
1
)(I
in

ik) (pu)
where,
p
1
= slope setting of DF1 (= 0.1 fixed)
ik = minimum operating current setting
When the default settings are applied, I
out
= 0.9× (I
in
– 0.5) × (CT secondary rated current). For
characteristic DF2, the theoretical outflow current is given by the following equation
I
out
= (1

p
2
) I
in
+ p
2
× kp (pu)
where,
p
2
= slope setting of DF2
kp = sensitivity setting of DF2
When the default settings are applied, I
out
= 1.0 × (CT secondary rated current).