Filter
Top Products
⎯ 133 ⎯
6 F 2 S 0 8 5 7
• Press 4 (= Logic circuit) on the "Test" sub-menu screen to display the "Logic circuit"
screen.
• Enter a signal number 44 to observe the DIF-A output at monitoring jack A and press the
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(2+p
1
)/2 + ik(2-p
1
)/4 (pu), characteristic DF1 is checked.
When the infeed current applied is larger than kp(2+ p
1
)/2 + ik(2- p
1
)/4 (pu), characteristic
DF2 is checked.
Note: When the default settings are applied, the critical infeed current which
determines DF1 checking or DF2 checking is 1.56
×(CT secondary rated
current).
• Apply an outflow current of the same magnitude and counterphase with the infeed current
to terminal TB1-9 and 10.
• Decrease the out flow current in magnitude and measure the values at which the element
operates.
• Check that the measured values are within 7% of the theoretical values.
For characteristic DF1, the theoretical outflow current is given by the following equation:
I
out
= (2−p
1
)(I
in
−ik)/(2+p
1
) (pu)
where, p
1
= slope setting of DF1
ik = minimum operating current setting
When the default settings are applied, I
out
= [(I
in
−0.3) / 3]× (CT secondary rated current).
For characteristic DF2, the theoretical outflow current is given by the following equation.
I
out
= [(2−p
2
)I
in
−(2−p
1
)ik + 2(p
2
− p
1
)kp]/(2+ p
2
) (pu)
where, p
2
= slope setting of DF2
kp = break point of DF1 and DF2
When the default settings are applied, I
out
= 0.43× (CT secondary rated current).
Operating time
The testing circuit is shown in Figure 6.5.4.