ABB 615 Series ANSI, Техническое руководство

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1MAC050144-MB C
Section 4
Protection functions
615 series ANSI 213
Technical Manual
4.1.10.9 Technical data
Table 204: 46R Technical data
4.1.11 Loss of load protection 37
4.1.11.1 Identification
4.1.11.2 Function block
Figure 99: Function block
4.1.11.3 Functionality
The loss of load protection 37 is used to detect a sudden load loss which is considered as
a fault condition.
37 picks up when the current is less than the set limit. It operates with the definite time
(DT) characteristics, which means that the function operates after a predefined trip time
and resets when the fault current disappears.
The function contains a blocking functionality. It is possible to block function outputs, the
definite timer or the function itself, if desired.
4.1.11.4 Operation principle
The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are Enable and Disable.
Pickup accuracy Depending on the frequency of the current
measured: f
n
±2Hz
±1.5% of the set value or ±0.002 x I
n
Pickup time
12
1. Negative sequence current before fault = 0.0, f
n
= 60 Hz, results based on statistical distribution of 1000
measurements
2. Includes the delay of the signal output contact
Minimum Typical Maximum
I
Fault
= 2.0 x set Pickup value 22 ms 24 ms 25 ms
Reset time < 40 ms
Reset ratio Typical 0.96
Retardation time < 35 ms
Trip time accuracy in definite time mode ±1.0% of the set value or ±20 ms
Suppression of harmonics DFT: -50dB at f = n x f
n
, where n = 2, 3, 4, 5,…
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Loss of load protection LOFLPTUC 3I< 37