Areva MiCOM P441 - P44 X;En AD;E44

P44x/EN AD/E44 Update Documentation
Page 22/82 MiCOM P441, P442 & P444
4.5 Tripping Logic
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There are five time delays associated with the six zones present. Zone 1 and extended zone
1 have the same time delay.
NB: See general trip equation in §2.5 from AP chapter
NB: All the timers are initiated when the general start of the relay picks up
(Z3Z4 convergence)
4.7 Power swing detection
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The power swing detection element may be used to selectively prevent when the measured
impedance point moves into the start-up characteristic from a power swing and still allows
tripping for a fault (fault evolving during a power swing). The power swing detection element
may also be used to selectively trip once an out-of-step condition has been declared.
For such feature a dedicated PSL must be designed in the internal logic of the relay
by using the graphic tool available in S1.(See AP chapter section 2.13).
When the locus of the 3 phase-phase loops leave the power swing polygon, the sign
of R is checked. If the R component still has the same sign as at the point of entry,
then the power swing is detected and managed in the internal logic as a stable swing.
Otherwise the locus of the 3 phase-phase loops have passed through the polygon
(indicating loss of synchronism) and the sign of R is different from the point of entry ;
then an out of step is detected.
Figure 14 illustrates the characteristics of power swing:
– Stable swing – same resistance sign
– Unstable swing (Out Of Step) – opposite resistance sign
4.7.1 Power swing detection
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The protection P44x differentiates since version C1.0 a stable power swing from a
loss of synchronism (out of step) condition.
A power swing is detected and declared if:
• At least one phase-phase impedance is within the start-up zone after having crossed
the power swing band in more than 5 ms.
• The three impedance points have been in the power swing band for more than 5 ms.
• At least two poles of the breaker are closed (impedance measurement possible on two
phases).
Remark :
During Power swing the residual compensation factor Ko are not
applied in the detection of the characteristic.(the extended limit in R
gives: R1=R2=R3=RpFwd)