ABB RELION 620 Series Technical Manual page 313

1MAC504801-IB E
620 series ANSI
Technical Manual
Leakage reactance (X )
leak
Measured voltage and load currents of the machine
Phase A-to-phase B voltage (V
Phase A current (I )
A
Phase B current (I )
B
Measured frequency (f )
m
The setting Voltage Max Cont
Voltage selection
The setting
Phase supervision
The setting
The pu leakage reactance X

V
n

X = X ⋅
leak Ω leakPU
(

I
n

GUID-7A3ABF69-50C4-4F5D-A466-61CAB055B604 V1 EN
The internal induced voltage E of the machine is calculated.
E V = + ( I − I ) ( ⋅ jX
AB A B leak
GUID-DBA66DD4-E087-4624-BDCE-E74167CAB5DE V1 EN
E = 11500∠0°+ (5600∠-63.57°- 5600∠176.42°) · (0.170378∠90°) = 12490 V
The excitation level M of the machine is calculated.
12490
Excitation level M =
11000
GUID-28DEBF41-9058-4C7B-985F-FA7131DF39A7 V1 EN
Example 2
The situation and the data are according to Example 1. In this case, the manufacturer of the
machine allows the continuous operation at 105 percent of the nominal voltage at the rated
load and this value to be used as the base for overexcitation.
20% or 0.2 pu
) 11500∠0° V
AB
5600∠-63.57° A
5600∠176.42° A
49.98 Hz
100%
phase-to-phase
A or AB
is converted to ohms.
leakPU
 
0 2 11000
 
= . ⋅
) (
 
⋅ 3 7455
 
)
49 98 .
= 1 1359 .
⋅ 1 00 .
50
Protection functions


= 0 0 170378 . ohms
)

⋅ 3

Section 4
(Equation 13)
(Equation 14)
(Equation 15)
307