Ashida ADR241B, Instruction Manual

Page: 95 / 272

ADR241B
Doc ID : ADR241B-DO_IM_01
Ref ID : ADR241B/IM/PLF
Rev No. : 06
Page No. : 95 of 272
4.4 Phase Over current Element (50/51)
Phase Over-current function operates for a set value of current with time delay (IDMT/DT).
This function provided with two stages, Where Stage 1 (IP>1) can be programmed as IDMT
or Definite Time (DT) provided with the Range of 2% to 400% in step of 1%. All major
international IDMT curves as well as Definite Time and User Define curves are available. The
Stage 2 (IP>2) can be programmed as Instantaneous or Definite Time (DT) provided with the
Range of 5% to 4000% in step of 1%.
The figure 4 represents the logic diagram of the phase over current protection function.
&
IDMT/
DT
IP>n Enable =
Yes
IP> n A Trip
IP> n A Pkp
A Phase Current
IP>n
+
-
Figure 4: Logic Diagram for the phase over current
The same logic will be applicable for B and C phase over current function.
Where n=1 to 2 stages of Over Current.
The Phase over Current logic checks the phase current is exceed the pickup value (IP>n)
and calculated operating time based on the curve selected in the IP>n Curve setting and
IP>n TMS or tIP>n DT Delay parameter settings. After satisfied all the above condition the
IED generates the phase over current trip.
4.5 Ground Over current Element (50N/51N)
4.5.1 Ground Over current (50/N/51N)
Ground Over-current function operates for a set value of current with time delay (IDMT/DT).
This function provided with two stages, Where Stage 1 (IE>1) can be programmed as IDMT
or Definite Time (DT) provided with the Range of 2% to 400% in step of 1%. All major
international IDMT curves as well as Definite Time and User Define curves are available. The
Stage 2 (IE>2) can be programmed as Instantaneous or Definite Time (DT) provided with the
Range of 5% to 3000% in step of 1%.
The following diagram figure 5 explains about the Ground over current protection function.