ABB RET670 Commissioning Manual page 165

1MRK 504 165-UUS -
Transformer protection RET670 2.2 ANSI
Commissioning manual
ForwardX

V arctan
∠ =

ts
ForwardR

EQUATION14058 V1 EN
frequency of V = 50 Hz
ts
I
CTs
I I 10459
= × =
50 s 50
I
CTp
EQUATION14059 V1 EN
∠I
= 0º
50s
frequency of I = 50 Hz
50s
I
CTs
It I 10459
= × =
tf
fs
I
CTp
EQUATION14062 V1 EN
∠I
= 0º
tfs
frequency of I = 50 Hz
tf
• Check that the service values (VOLTAGE, CURRENT, R(%), X(%) ) are according
to the injected quantities and that ROTORANG is close to 3.14 rad. For this particular
injection the service values are:
• VOLTAGE = 10.74 kV
• CURRENT = 20918 A
• R = 7.37%
• X = 53.40%
• ROTORANG = -3.09 rad
Note that these values identify a point inside the lens characteristic, in the zone 2, that
is close to the point RE. The START is issued, but no TRIP is performed.
Execution of the dynamic test
The test may be performed by using two states of a sequence tool that is a basic feature of
test sets.
• State 1: pre-test condition.
Steady voltage and current are applied in order to get a steady high impedance, that
is, a point in the plane R-X which is far away from the lens characteristic. Define the
following three-phase symmetrical quantities (the phase angle is related to phase L1):
V
VT s ,
V 0 9 . V
= × ×
ts t FwdZ ,
V
VT p ,
EQUATION14063 V1 EN
Testing functionality by secondary injection
59 33 .
  
arctan 82. . 14°
 =  =

8 19 .
  
1
= . 1 162 A
×
9000
1
1 162 . A
× =
9000
0 1 .
0 9 11931 . 77 81 .
= × × =
13 8 .
Section 11
V
(Equation 28)
(Equation 29)
(Equation 30)
(Equation 31)
159