-3V
0
=V
ref
Trip area
Instrument
transformer
angle error
3I
0
(prim)
3I
0
(to prot)
Characteristic after
angle compensation
RCAcomp
ANSI06000651-2-en.vsd
RCADir = 0º
ANSI06000651 V2 EN-US
Figure 49: Explanation of RCAcomp
Operation mode 3I
0
· 3V
0
· cos φ
SEMOD175060-76 v8
1. Set the polarizing voltage to 1.2 · VNRelPU and set the phase angle between voltage and current
to the set characteristic angle (RCADir). Note that the current lagging the voltage.
2. Inject current until the function picks up, and make sure that the trip power is equal to the SN_PU
setting for the set directional element.
Note that for pick-up, both the injected current and voltage must be greater than the set values
INRelPU and VNRelPU respectively.
The function activates the PICKUP and PUDIRIN outputs.
3. Assume that φ´ is the phase angle between injected voltage (3V
0
) and current (3I
0
) i.e. φ´ =
RCADir-φ. Change φ´ to for example 45 degrees. Increase the injected current until the function
trips.
4. Compare the result with the set value and make sure that the new injected 3I
0
· 3V
0
· cos φ is equal
to the setting SN_PU. Take the set characteristic into consideration, see figure
48 and figure 49.
5. Measure the trip time of the timer by injecting 1.2 · VNRelPU and a current to get two times the set
SN_PU trip value.
Section 11 1MRK 504 165-UUS Rev. J
Testing functionality by secondary injection
176 Transformer protection RET670
Commissioning manual
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