63
3 zone impedance protection (Z(n)RW)
&KDSWHU
/LQHLPSHGDQFH
)LJXUH 0HDVXUHPHQWSULQFLSOHVIRUWKHLPSHGDQFHSURWHFWLRQ
A resistance and reactance calculation with a complex power comparison is performed
between the circles according to the formula:
(Equation 20)
A counter tracks how many times the set operate conditions are fulfilled. This is done
to eliminate the risk for unwanted/faulty operation due to transient measurement uncer-
tainty. When the total exceeds a level that corresponds to 2/3 periods, a memory ele-
ment is activated to mark that the measured impedance is low.
The slope for the directional lines is calculated in the same way, but by using memory
voltage. As the phase position of the voltage is available for a further period during the
fault, a selective determination of direction can be made, even if the fault voltage is very
low. If the fault voltage remains low and the fault current exceeds the lowest operate
current, tripping is completed if the impedance is low. If the fault is in the reverse di-
rection, the reverse directional measuring element will remain functional.
R
jX
en02000640.vsd
S
U I
*
R
set
j X
set
⋅
+
(
)
I
2
⋅
<
⋅
=
Содержание REO 517
Страница 10: ... RQWHQWV ...
Страница 16: ...6 Introduction to the application manual KDSWHU QWURGXFWLRQ ...
Страница 64: ...54 Blocking of signals during test KDSWHU RPPRQ IXQFWLRQV ...
Страница 88: ...78 Scheme communication logic ZCOM KDSWHU LQH LPSHGDQFH ...
Страница 100: ...90 Time delayed phase and residual overcurrent protection TOC1 KDSWHU XUUHQW Equation 36 Iset IsSEC I1b 100 ...
Страница 146: ...136 Unbalance protection for capacitor banks TOCC KDSWHU XUUHQW ...
Страница 166: ...156 Dead line detection DLD KDSWHU 3RZHU V VWHP VXSHUYLVLRQ ...
Страница 171: ...161 About this chapter KDSWHU RQWURO KDSWHU RQWURO ERXW WKLV FKDSWHU This chapter describes the control functions ...
Страница 293: ...283 About this chapter KDSWHU RJLF KDSWHU RJLF ERXW WKLV FKDSWHU This chapter describes the logic functions ...
Страница 378: ...368 Monitoring of DC analog measurements KDSWHU 0RQLWRULQJ ...
Страница 379: ...369 About this chapter KDSWHU 0HWHULQJ KDSWHU 0HWHULQJ ERXW WKLV FKDSWHU This chapter describes the metering functions ...
Страница 384: ...374 Pulse counter logic PC KDSWHU 0HWHULQJ ...
Страница 412: ...402 Serial communication modules SCM KDSWHU DWD FRPPXQLFDWLRQ ...
Страница 440: ...430 LED indication module KDSWHU DUGZDUH PRGXOHV ...