ABB Relion 650 Series Technical Manual page 611

1MRK 506 326-UUS B
æ
n
å
ç
D ×
t
ç
è
=
j 1
EQUATION1644 V1 EN-US
where:
j = 1
Dt
n
i (j)
For inverse time operation, the inverse time characteristic is selectable. Both the IEC and ANSI/
IEEE standardized inverse time characteristics are supported.
For the IEC curves there is also a setting of the minimum time-lag of operation, see figure 304.
Operate
time
tMin
IEC05000133 V2 EN-US
Figure 304: Minimum time-lag operation for the IEC curves
In order to fully comply with IEC curves definition setting parameter tMin shall be set to the value
which is equal to the operating time of the selected IEC inverse time curve for measured current of
Line distance protection REL650
Technical manual
ö
( )
P
æ ö
i j
÷
- ³ ×
ç ÷ C A td
÷
è ø
Pickupn
ø
IMin
© Copyright 2011 ABB Power Grids. All rights reserved
is the first protection execution cycle when a fault has been detected,
that is, when
i
>
1
Pickupn
EQUATION1646 V1 EN-US
is the time interval between two consecutive executions of the
protection algorithm,
is the number of the execution of the algorithm when the trip time
equation is fulfilled, that is, when a trip is given and
is the fault current at time j
Current
IEC05000133-3-en.vsd
Section 21
Time inverse characteristics
(Equation 100)
605