GE Multilin g60 Instruction Manual page 342

5.6 GROUPED ELEMENTS
5
The split phase element principle of operation is as follows. First, define the following parameters:
I : split-phase current, I
split
Then, the expected value of the steady state unbalance (defined as bias current) is expressed as follows:
where:
and offset is the split phase current at no-load. In "Over" mode, the element will pickup if:
In "Over-under", mode, the element will pickup if:
5-182
830728A1.CDR
Figure 5–91: SPLIT PHASE PROTECTION FOR 2 CTS
830727A1.CDR
Figure 5–92: SPLIT PHASE PROTECTION FOR 1 CT
: load current, pickup: pickup setting, min_load: minimum load supervision setting
load
I slope I
=
bias
I
Load CT Primary
split

---------- - ---------------------------------------------------- -
slope
=
I Load CT Secondary
load
  
I I pickup
–
split bias
 
I I pickup
–
split bias
G60 Generator Protection System
Split Phase Load
Source Source
Split Phase Load
Source Source

offset
+
load
Split Phase CT Secondary

--------------------------------------------------------------------- -
Split Phase CT Primary
  
and I min_load
load
   
and I min_load
load
5 SETTINGS
(EQ 5.24)
(EQ 5.25)
(EQ 5.26)
(EQ 5.27)
GE Multilin