ABB Relion REG670, Applications Manual

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Curve name
IEC Very Inverse
IEC Inverse
IEC Extremely Inverse
IEC Short Time Inverse
IEC Long Time Inverse
IEC Definite Time
User Programmable
ASEA RI
RXIDG or RD (logarithmic)
It is also possible to tailor make the inverse time characteristic.
Normally it is required that EF4PTOC shall reset as fast as possible when the current
level gets lower than the operation level. In some cases some sort of delayed reset is
required. Therefore different kinds of reset characteristics can be used.
For some protection applications, there can be a need to change the current operating
level for some time. Therefore, there is a possibility to give a setting of a multiplication
factor
INxMult to the residual current pick-up level. This multiplication factor is
activated from a binary input signal ENMULTx to the function.
Power transformers can have a large inrush current, when being energized. This
inrush current can produce residual current component. The phenomenon is due to
saturation of the transformer magnetic core during parts of the cycle. There is a risk
that inrush current will give a residual current that reaches level above the operating
current of the residual overcurrent protection. The inrush current has a large second
harmonic content. This can be used to avoid unwanted operation of the protection.
Therefore, EF4PTOC has a possibility of second harmonic restrain if the level of 2
nd
harmonic current reaches a value above a set percent of the fundamental current.
9.4.3 Setting guidelines
When inverse time overcurrent characteristic is selected, the operate
time of the stage will be the sum of the inverse time delay and the set
definite time delay. Thus, if only the inverse time delay is required, it
is important to set the definite time delay for that stage to zero.
The parameters for the four step residual overcurrent protection are set via the local
HMI or PCM600. The following settings can be done for the function.
Common base IED values for primary current ( IBase ), primary voltage ( UBase ) and
primary power ( SBase ) are set in the global base values for settings function
GBASVAL.
Section 9
1MRK 502 071-UEN -
Current protection
340 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual