Ashida ADR233B - Transformer Differential Protection

ADR233B
Doc ID : ADR233B/IM/01
Ref ID : ADR233B/IM/I&S
Rev No. : 05
Page No. : 35 of 479
Accuracy of protection function:
I. TRANSFORMER DIFFERENTIAL PROTECTION
For operating Value Pick-up Calculated difference +/- 5% or 20mA (1A
input), or 100mA (5A input) whichever is greater
Drop –off 0.95 x Formula ±5%
For operating Time Differential DT
Operation
< 55ms (Currents applied at 2x pickup level or
higher)
High Set-1 (IHs>1) <40ms (Currents applied at 2x pickup level or
higher)
High Set-2 (IHs>2) <40ms (Currents applied at 2x pickup level or
higher)
II. Harmonic Blocking:
For operating Value 2
nd
Harm Thresh Setting ±15%
4
th
Harm Thresh Setting ±15%
5
th
Harm Thresh Setting ±15%
III. High Impedance REF:
For operating Value Pick-up Setting +10% / - 5%
Drop –off 0.95 x Setting ±5%
For operating Time DT Operation < 30ms (Currents applied at 2x pickup level or
higher)
IV. Low Impedance REF:
For operating Value Pick-up Calculated difference +/- 5% or 20mA (1A
input), or 100mA (5A input) whichever is greater
Drop –off 0.95 x Formula ±5%
For operating Time DT Operation < 55ms (Currents applied at 2x pickup level or
higher)
V. Phase Over current (W1/W2):
For operating Value
DT Pick–up
Setting ±5%
IDMT Pick–up 1.05 x Setting ±5%
Drop –off 0.95 x Setting ±5%
For operating Time IDMT Characteristic
shape
As per class5 of 60255-151 cl.5.2**
or 50ms whichever is greater
DT Operation ±5% or 55ms whichever is greater* Note 1
VI. Ground Over current:
For operating Value
DT Pick–up
Setting ±5%
IDMT Pick–up
1.05 x Setting ±5%
Drop –off 0.95 x Setting ±5%
For operating Time IDMT Characteristic
shape
As per class5 of 60255-151 cl.5.2**
or 50ms whichever is greater