73
Automatic switch onto fault logic (SOTF)
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The external activation is achieved by an input (SOTF-BC), which should be set high
for activation, and low when the breaker has closed. This is carried out by an NC aux-
iliary contact of the circuit breaker or by the closing order to the breaker.
The internal automatic activation is controlled by the DLD function and its functional
output DLD--START. The DLD--START functional output is activated when all phase
voltages and phase currents have been below their set operate values. The DLD--
START functional output is usually configured to the SOTF-DLCND functional input.
It activates the operation of the SOTF function, if present for more than 200 ms without
the presence of a non-directional impedance starting signal SOTF-NDACC.
Operation of a SOTF function can be blocked by the activation of a SOTF-BLOCK
functional input.
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The parameters for the switch-onto-fault function are set via the local HMI or PST (Pa-
rameter Setting Tool). Refer to the Technical reference manual for setting parameters
and path in local HMI.
The low voltage and low current criteria for automatic activation is settable under the
DLD-- function. Refer to the Technical reference manual for setting parameters and
path in local HMI.
This setting is not critical as long as it is lower then the lowest operation voltage during
normal and emergency conditions.
The distance protection zone used for a switch-onto-fault criterion (SOTF zone) have
to be set to cover the entire protected line with a safety margin of minimum 20%.
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 ...