ABB RELION 620 Series Technical Manual page 628

Section 6
Supervision functions
6.6.9
6.7
6.7.1
6.7.2
6.7.3
622
Technical data
Table 448: 66/51LRS Technical data
Characteristic
Operation accuracy
1)2)
Pickup time
I
Fault
detection A
Trip time accuracy
Reset ratio
1) Current before = 0.0 × I , f
n
1000 measurements
2) Includes the delay of the signal output contact
Cable fault detection CFD
Identification
Function description
Cable fault detection
Function block
GUID-F730AEE9-271E-4CFD-893A-FFF525AF806F-ANSI V1 EN
Figure 317: Function block
Functionality
The self-clearing fault detection function CFD calculates the half-cycle DFT of the
current signal for all three phases and uses it to detect a self-clearing fault pronounced
primarily in underground circuits.
Value
Depending on the frequency of the measured
current: f
±1.5% of the set value or ±0.002 × I
Minimum
= 1.1 × set Pickup
29 ms
±1.0% of the set value or ±20 ms
Typically 0.90
= 60 Hz, overcurrent in one phase, results based on statistical distribution of
n
IEC 61850
identification
RCFD
1MAC504801-IB E
±2 Hz
n
n
Typical Maximum
31 ms 34 ms
IEC 60617 ANSI/IEEE C37.2
identification device number
CFD CFD
620 series ANSI
Technical Manual