Alstom MiCOM P846, Technical Manual

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Application Notes P846/EN AP/D
MiCOM P846
(AP) 6-5
Vbase
(kV)
Base Power
(MW)
Line Charging
(MVar/km)
Line Charging
(p.u./km)
Line Charging
(km/p.u.)
120 36 0.047 0.00131 763
138 48 0.062 0.00129 775
161 65 0.081 0.00125 800
220 128 0.160 0.00125 800
230 139 0.178 0.00128 781
345 420 0.532 0.00127 787
500 866 1.12 0.00129 775
735 2081 2.67 0.00128 781
765 2276 2.92 0.00128 781
1100 5272 6.71 0.00127 787
Table 1 Transmission lines SIL Base Power and Line Charging parameters
Figure 1 shows the typical configuration of a line in a HV/EHV substation with its capacitive
voltage transformer CVT and current transformers CT1, CT2 and CT3. CT1 and CT2 are
externally summated to give the feeder current to the relay. CT3 measures the reactor
current which is essentially subtracted from the feeder current to give the line current.
AP
D D
D
SUBSTATION
BUSBARS
CVT
LINE BREAKERS
SHUNT REACTOR
I
LINE
LINE
DISCONNECTOR
P4063ENa
I
CT1
CT1
I
CT2
CT2
REACTOR
CT3
Figure 1: Configuration of a line in a HV/EHV substation
Since it only relies on voltages and currents to make its decision, the DLO is designed with
the following reliability, security and speed requirements in mind when applied to power
systems: