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Scheme communication logic (ZCOM)
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To achieve fast fault clearing for a fault on the part of the line not covered by the instan-
taneous zone 1, the stepped distance protection function can be supported with logic,
that uses communication channels.
One communication channel in each direction, which can transmit an on/off signal is
required. The performance and security of this function is directly related to the trans-
mission channel speed, and security against false or lost signals. For this reason special
channels are used for this purpose. When power line carrier is used for communication,
these special channels are strongly recommended due to the communication distur-
bance caused by the primary fault.
The logic supports the following communications schemes; blocking scheme, permis-
sive schemes (overreach and underreach) and direct intertrip.
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Depending on whether a reverse or forward directed impedance zone is used to issue
the send signal (ZCOM-CS), the communication schemes are divided into Blocking
and Permissive schemes, respectively.
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In a blocking scheme, the received signal (ZCOM-CR) carries information about the
fault position, which specifies that it is outside the protected line, on the bus or on ad-
jacent lines. Do not prolong the sent signal, so set tSendMin to zero. The sending might
be interrupted by operation of a forward zone if it is connected to ZCOM-CSNBLK.
An overreaching zone is allowed to trip after a co-ordination time (tCoord), when no
signal is received from the remote terminal. The tCoord time must allow for the trans-
mission of the blocking signal with a certain margin.
In case of external faults, the blocking signal (ZCOM-CR) must be received before the
tCoord elapses, to prevent a false trip.
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 ...