ABB RET670 - Page 163

I I
I
I
A
s
CTs
CTp
50 50
10459
1
9000
1 162= × = × = .
EQUATION14059 V1 EN (Equation 19)
∠I
50s
=0°
frequency of I
50s
= 50 Hz
It I
I
I
A
fs
CTs
CTp
tf= × = × =10459
1
9000
1 162.
EQUATION14062 V1 EN (Equation 20)
∠I
tfs
=0°
frequency of I
tfs
= 50 Hz
• Check that the service values (VOLTAGE, CURRENT, R(%), X(%)) are according
to the injected quantities and that ROTORANG is close to 0 rad.
For this particular injection the service values are:
• VOLTAGE = 13.12 kV
• CURRENT = 20918 A
• R = 9.01%
• X = 65.27%
• ROTORANG = 0.04 rad
Note that these values identify a point outside the lens characteristic, even if it is close to
the point RE. Neither START nor TRIP is issued.
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. This
is a point in the plane R-X that is far away from the lens characteristic. Define the
following three-phase symmetrical quantities (the phase angle is related to phase L1):
V V
V
V
V
ts t FwdZ
VT s
VT p
= × × = × × =1 1 1 1 11931
0 1
13 8
95 1. .
.
.
.
,
,
,
EQUATION14057 V1 EN (Equation 21)
∠ =






=






=V
ForwardX
ForwardR
ts
arctan arctan
.
.
59 33
8 19
82..14°
EQUATION14058 V1 EN (Equation 22)
frequency of V
ts
= 50 Hz
I
50s
=0 A
1MRK 504 165-UUS - Section 11
Testing functionality by secondary injection
Transformer protection RET670 2.2 ANSI 157
Commissioning manual