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3 zone impedance protection (Z(n)RW)
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The measuring elements receive information about currents and voltages from the A/D
converter. The checksums are calculated and compared, after which the information is
saved in memory. Squared RMS amplitudes of voltage and current are calculated and
compared according to the formula:
(Equation 19)
and results in one inner and one outer impedance circle. The outer circle, circumscribed,
indicates a start zone, which gives an efficient delimitation outwards towards the tran-
sient fault during normal load conditions. The inner circle, inscribed, delimits the near-
field, where the rapid function for short circuit faults can be obtained without jeopar-
dizing the selectivity.
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Summary of Contents for REO 517
Page 10: ... RQWHQWV ...
Page 16: ...6 Introduction to the application manual KDSWHU QWURGXFWLRQ ...
Page 64: ...54 Blocking of signals during test KDSWHU RPPRQ IXQFWLRQV ...
Page 88: ...78 Scheme communication logic ZCOM KDSWHU LQH LPSHGDQFH ...
Page 146: ...136 Unbalance protection for capacitor banks TOCC KDSWHU XUUHQW ...
Page 166: ...156 Dead line detection DLD KDSWHU 3RZHU V VWHP VXSHUYLVLRQ ...
Page 378: ...368 Monitoring of DC analog measurements KDSWHU 0RQLWRULQJ ...
Page 384: ...374 Pulse counter logic PC KDSWHU 0HWHULQJ ...
Page 412: ...402 Serial communication modules SCM KDSWHU DWD FRPPXQLFDWLRQ ...
Page 440: ...430 LED indication module KDSWHU DUGZDUH PRGXOHV ...