ABB Relion 611 Series, Technical Manual

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Operating curve type EFLPTOC EFHPTOC
(14) IEC Long Time Inverse x
(15) IEC Definite Time x x
(17) User programmable curve x x
(18) RI type x
(19) RD type x
EFIPTOC supports only definite time characteristics.
For a detailed description of timers, see the General function block
features section in this manual.
Table 154: Reset time characteristics supported by different stages
Reset curve type EFLPTOC EFHPTOC Note
(1) Immediate x x Available for all operate time curves
(2) Def time reset x x Available for all operate time curves
(3) Inverse reset x x Available only for ANSI and user
programmable curves
The Type of reset curve setting does not apply to EFIPTOC or when
the DT operation is selected. The reset is purely defined by the Reset
delay time setting.
4.2.1.7 Application
EFxPTOC is designed for protection and clearance of earth faults in distribution and
sub-transmission networks where the neutral point is isolated or earthed via a
resonance coil or through low resistance. It also applies to solidly earthed networks
and earth-fault protection of different equipment connected to the power systems,
such as shunt capacitor bank or shunt reactors and for backup earth-fault protection of
power transformers.
Many applications require several steps using different current start levels and time
delays. EFxPTOC consists of three different protection stages.
• Low EFLPTOC
• High EFHPTOC
• Instantaneous EFIPTOC
1MRS757454 D
Section 4
Protection functions
611 series 165
Technical Manual