ABB 615 series Technical Manual page 387

1MAC059074-MB A
615 series ANSI
Technical Manual
Operation characteristic
After the admittance calculation is released, the calculated neutral admittance is compared
to the admittance characteristic boundaries in the admittance plane. If the calculated
neutral admittance Yo moves outside the characteristic, the enabling signal is sent to the
timer.
21YN supports a wide range of different characteristics to achieve the maximum
flexibility and sensitivity in different applications. The basic characteristic shape is
selected with the Operation mode and Directional mode settings. Operation mode defines
which operation criterion or criteria are enabled and Directional mode defines if the
forward, reverse or non-directional boundary lines for that particular operation mode are
activated.
Table 378: Operation criteria
Operation mode
Yo
Bo
Go
Yo, Go
Yo, Bo
Go, Bo
Yo, Go, Bo
The options for the Directional mode setting are "Non-directional", "Forward" and
"Reverse".
Figure 178, Figure 179 and
by 21YN and the settings relevant to that particular characteristic. The most typical
characteristics are highlighted and explained in details in the chapter
characteristics. Operation is achieved when the calculated neutral admittance Yo moves
outside the characteristic (the operation area is marked with gray).
The settings defining the admittance characteristics are given in primary
milliSiemens (mS). The conversion equation for the admittance from
secondary to primary is:
Description
Admittance criterion
Susceptance criterion
Conductance criterion
Admittance criterion combined with the conductance
criterion
Admittance criterion combined with the susceptance
criterion
Conductance criterion combined with the
susceptance criterion
Admittance criterion combined with the conductance
and susceptance criterion
Figure 180 illustrate the admittance characteristics supported
Section 4
Protection functions
Neutral admittance
381