BBC Distance relay
BBC Distance relay
(OP)
Hi, I'm in need for some help, it's regarding an old distance relay of electromechanical type, BBC LI41b, see attached image. The protection relay will be exchanged with a newer one, not decided yet, because of age and no spare parts available.
I have managed to get hold of a data paper of a BBC LI41a, but i cannot properly grasp the settings, to transform them to a newer protection relay.
The starting element seems to be of overcurrent type and a setting of 5A.
Zone1: 120%, zone2:67%, zone3: 0% and zoneA: 67%.
The replica impedance setting is, cot fi=0,6 and tan fi=1 with a reach of 0,2 ohm/ph.
Is there a way to get this vector in a+bi form?
Isn't 0,2 ohm/ph with a angle of (cot fi = 0,6 => fi = 59 degrees) very low?
No k0-factor.
The transmission line is 980m AXKJ 3x1x300mm2 (underground) + 1150m FeAl 3x234mm2 (overhead).
Or is there a better way to protect this short line?, directional overcurrent relay?
Sincerly Fredrik ;)
I have managed to get hold of a data paper of a BBC LI41a, but i cannot properly grasp the settings, to transform them to a newer protection relay.
The starting element seems to be of overcurrent type and a setting of 5A.
Zone1: 120%, zone2:67%, zone3: 0% and zoneA: 67%.
The replica impedance setting is, cot fi=0,6 and tan fi=1 with a reach of 0,2 ohm/ph.
Is there a way to get this vector in a+bi form?
Isn't 0,2 ohm/ph with a angle of (cot fi = 0,6 => fi = 59 degrees) very low?
No k0-factor.
The transmission line is 980m AXKJ 3x1x300mm2 (underground) + 1150m FeAl 3x234mm2 (overhead).
Or is there a better way to protect this short line?, directional overcurrent relay?
Sincerly Fredrik ;)






RE: BBC Distance relay
RE: BBC Distance relay
cot φ = 0,6 → φ = 59˚
cos 59 = r/0,2 → r = 2,6
sin 59 = x/0,2 → x = 4,3j
RE: BBC Distance relay