-3U
0
=U
ref
Operate area
Instrument
transformer
angle error
3I
0
(prim)
3I
0
(to prot)
Characteristic after
angle compensation
RCAcomp
IEC06000651-3-en.vsd
RCADir = 0º
IEC06000651 V3 EN-US
Figure 44: Explanation of RCAcomp
Operation mode 3I
0
· 3U
0
· cos φ
SEMOD175060-76 v8
1. Set the polarizing voltage to 1.2 · UNRel> 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 operate
power is equal to the SN> setting for the set directional element.
Note that for operation, both the injected current and voltage must be greater
than the set values INRel> and UNRel> respectively.
The function activates the START and STDIRIN outputs.
3. Assume that φ´ is the phase angle between injected voltage (3U
0
) and current
(3I
0
) i.e. φ´ = RCADir-φ. Change φ´ to for example 45 degrees. Increase the
injected current until the function operates.
4. Compare the result with the set value and make sure that the new injected 3I
0
· 3U
0
· cos φ is equal to the setting SN>. Take the set characteristic into
consideration, see figure
43 and figure 44.
Section 11 1MRK 505 378-UEN A
Testing functionality by secondary injection
180 Line differential protection RED670 2.2 IEC
Commissioning manual
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