and the voltages that are related to them:
V Z I R X I
t FwdZ FwdZ t FwdR FwdX t,
. . .= × = + × = + × =
2 2 2 2
0 078 0 565 20918 0 5700 20918 11931× = V
EQUATION14052 V1 EN-US (Equation 16)
V Z I R X I
t RvsZ RvsZ t RvsR RvsX t,
. . .= × = + × = + × =
2 2 2 2
0 003 0 282 20918 0 2822 20918 5899× = V
EQUATION14053 V1 EN-US (Equation 17)
The previous calculations are in primary values. They are transferred to secondary values to perform
injections by a test set. Primary values are transferred to secondary values by taking into account the CT
ratio and the VT ratio (respectively 9000/1 A and 13.8/0.1 kV in the example).
The magnitude of the secondary voltages, that are related to the points RE and SE of the R-X plane,
needs to be checked.
RE (R
FwdR
, X
FwdX
):
V V
V
V
V
t FwdZs t FwdZ
VT s
VT p
, ,
,
,
.
.
.= × = × =11931
0 1
13 8
86 45
EQUATION14054 V1 EN-US (Equation 18)
SE (R
RvsR
, X
RvsX
):
V V
V
V
V
t RvsZs t RvsZ
VT s
VT p
, ,
,
,
.
.
.= × = × =5899
0 1
13 8
42 75
EQUATION14055 V1 EN-US (Equation 19)
The tests, which are described in this section, may require voltages that have magnitude equal to 110%
of the previous values. The continuous permissive overload voltage of the protection voltage channels of
the TRM module is 420 V; so the previous voltages may be applied to the analog channels of the IED
continuously. Limitations may be related to the available test set; the current I
t
was calculated by using a
factor 2.5 (instead of the maximum value 4) in order to reduce the magnitude of the test voltage for the
points RE and SE.
Test sets usually do not have a feature to simulate a real network during a power swing and apply the
related analog quantities at the terminal of the generator. The scope of the present test is not a
simulation of a real network. Voltages and currents are supplied in order to measure an impedance that
changes in the time and traverses the plane R-X and, in particular, the area inside the lens characteristic.
The test may be performed by applying:
• Symmetric three-phase voltage at 50 Hz. The magnitude depends on the point of the characteristic
that needs to be verified. The following three main points of the line segment SE-RE need to be
checked:
• the point RE (R
FwdR
, X
FwdX
)
• a point which is related to the parameter ReachZ1 (boundary between zone 1 and zone 2)
• the point SE (R
RvsR
, X
RvsX
)
The phase angle of the test voltages is equal to:
• arctan (ForwardX/ForwardR) for tests in the quadrant 1 and 2 of the R-X plane
• arctan (ReverseX/ReverseR) -180° for tests in the quadrant 3 and 4 of the R-X plane
1MRK 504 165-UUS Rev. J Section 11
Testing functionality by secondary injection
Transformer protection RET670 147
Commissioning manual
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