ABB REL300 Instruction Manual page 123

I.L. 40-385.7
then REL300 will automatically calculate the zero sequence current compensation factor (k
by using the value of ZR, PANG, GANG and equation (1) in section 3.2.1 (page 3-2), i.e.,
k
5.1.2 Zone 1 Distance Unit Settings
A setting of 80% of the line impedance for zone-1 reach is recommended, thus the Zone-1
phase and ground reach should be:
Z1P = 6 x 0.8 = 4.8 and
Z1G = 6 x 0.8 = 4.8
NOTE: Z1P and Z1G can be set for different values if the application is required.
5.1.3 Zone 2 and Pilot Distance Unit Settings
Generally, Zone-2 reach is set for 100% of the protected line plus 50% of the shortest adjacent
line, For this example, if the shortest (or only) adjacent line primary impedance is 20 ohms, then
the Zone-2 reach setting would be:
Z2P = 6 + (20 x 0.5) x 240/600 = 10 and
Z2G = 10
The pilot zone distance phase and ground reaches can be set either exactly or nearly equal to
the Zone 2 phase and ground distance reach, which depends on the application. For this ex-
ample, set it equal to Zone 2 reach, i.e.,
PLTP = 10
NOTE: Z2P, Z2G, PLTP and PLTG can be set for different values or disabled if the application
is required.
5.1.4 Zone 3 Distance Unit Settings
Generally, Zone-3 reach is set to underreach of the shortest Zone 2 reach of the adjacent line
off the remote bus. A practical setting is set for 100% of the protected line plus 100% of the
shortest adjacent line off the remote bus. For example, if the shortest Zone 2 reach off the re-
mote bus is 25 ohms primary, and infeed effect may increase its impedance by 30%, then the
Zone 3 reach setting should be:
Z3P = 6 + (25 x 1.3) x 240/600 = 19 and
Z3G = 19
NOTE: Z3P and Z3G can be set for different values if the application is required.
5.1.5 Overcurrent Unit Setting
a. The low set phase overcurrent unit is used for supervising the load-loss-trip and CIF func-
tions. It should be set higher than the line charging current and below the minimum load
current.
NOTE: It should be set above the maximum tapped load current if applicable.
5-2
= ZR ∠(GANG-PANG)-1
= (Z -Z )/Z
o 0L 1L 1L
and PLTG = 10
)
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