Table 505: 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 pro-
grammable 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.
4.2.1.8 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
EFLPTOC contains several types of time-delay characteristics. EFHPTOC and
EFIPTOC are used for fast clearance of serious earth faults.
4.2.1.9 Signals
EFLPTOC Input signals
Table 506: EFLPTOC Input signals
Name Type Default Description
IRES SIGNAL - Residual current
BLOCK BOOLEAN 0=False Block signal for acti-
vating the blocking
mode
ENA_MULT BOOLEAN 0=False Enable signal for cur-
rent multiplier
1MRS759142 F Protection functions
REX640
Technical Manual
445
To Next Page
Loading...
