ABB Relion 650 Series Applications Manual page 88

Section 7
Current protection
The parameters for the four step residual overcurrent protection, zero or negative sequence
direction EF4PTOC (51N/67N) are set via the local HMI or PCM600.
The following settings can be done for the four step residual overcurrent protection.
GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ), ( VBase )
SBase ).
and (
SeqTypeUPol : It is used to select type of voltage polarization quantity, i.e. ZeroSeq and NegSeq for
direction detection.
SeqTypeIPol : It is used to select type of current polarization quantity, i.e. ZeroSeq and NegSeq for
direction detection.
SeqTypeIDir : It is used to select type of operating quantity, i.e. ZeroSeq and NegSeq for direction
detection.
Operation : Sets the protection to Enabled or Disabled .
EnaDir : Enables the directional calculation in addition to the directional mode selection in each
step.
7.2.3.1 Settings for steps 1 and 4
DirModeSelx : The directional mode of step x . Possible settings are Disabled / Non-directional /
Forward / Reverse .
Characteristn : Selection of time characteristic for step n . Definite time delay and different types of
inverse time characteristics are available.
Inverse time characteristic enables fast fault clearance of high current faults at the same time as
selectivity to other inverse time phase overcurrent protections can be assured. This is mainly used
in radial fed networks but can also be used in meshed networks. In meshed networks the settings
must be based on network fault calculations.
To assure selectivity between different protections, in the radial network, there have to be a
minimum time difference Dt between the time delays of two protections. The minimum time
difference can be determined for different cases. To determine the shortest possible time
difference, the operation time of protections, breaker opening time and protection resetting time
must be known. These time delays can vary significantly between different protective equipment.
The following time delays can be estimated:
Protection operate time:
Protection resetting time:
Breaker opening time:
The different characteristics are described in the Technical Manual (TM).
82
n means step 1 and 4. x means step 1, 2, 3 and 4.
15-60 ms
15-60 ms
20-120 ms
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1MRK 505 287-UUS B
M15282-9 v7.1.1
Busbar protection REB650
Application manual