110
Two step definite and inverse time-
delayed residual
overcurrent protection (TEF1 and TEF2)
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The parameters for the two step definite and inverse time-delayed residual overcurrent
protection function are set via the local HMI or PST (Parameter Setting Tool). Refer to
the Technical reference manual for setting parameters and path in local HMI.
To detect high resistive earth-faults, a low operate current is required. On the other
hand, a low setting increases the risk for unwanted operation due to imbalance in the
network and the current transformer circuits. Set the minimum operate current
(IN>Low) of the earth-fault overcurrent protection higher than the maximum false
earth-fault current. If the directional function is chosen, set the start level of the direc-
tional function (IN> Dir) higher than the maximum false earth-fault current.
The choice of time delay characteristics - definite time, normal inverse, very inverse,
extremely inverse or RI inverse - depends on the network. To achieve optimum selec-
tivity, use the same type of characteristic for all earth-fault overcurrent protections in
the network. This means that in networks already equipped with earth-fault overcurrent
relays, the best selectivity is normally achieved by using the same type of characteristic
as in the existing relays.
The following formulas for the operate time (in seconds) apply to the characteristic used
within the REO 517 terminal, see table 10.
7DEOH 2SHUDWHWLPHIRUPXODV
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2SHUDWHWLPHV
Normal inverse
(Equation 52)
Very inverse
(Equation 53)
Extremely inverse
(Equation 54)
RI inverse
(Equation 55)
t
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0.02
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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 ...