Unsymmetrical Current Detection - ABB Relion Technical Manual

Section 8
Current protection
8.6.7.2
8.6.8
8.7
8.7.1
252

Unsymmetrical current detection

Unsymmetrical current indicated if:
• any phase current is lower than CurrUnsymPU of the highest current in the three
phases.
• the highest phase current is greater than CurrRelPU of IBase.
If these conditions are true, an unsymmetrical condition is detected. This detection is
enabled to generate a trip after a set time delay tTrip if the detection occurs in the next 200
ms after the circuit breaker has received a command to open trip or close and if the
unbalance persists. The 200 ms limitation is for avoiding unwanted operation during
unsymmetrical load conditions.
The pole discrepancy protection is informed that a trip or close command has been given
to the circuit breaker through the inputs CLOSECMD (for closing command information)
and OPENCMD (for opening command information). These inputs can be connected to
terminal binary inputs if the information are generated from the field (that is from
auxiliary contacts of the close and open push buttons) or may be software connected to the
outputs of other integrated functions (that is close command from a control function or a
general trip from integrated protections).
Technical data
Table 120: CCRPLD (52PD) technical data
Function
Operate value, current
asymmetry level
Reset ratio
Time delay
Directional over-/under-power protection GOPPDOP/
GUPPDUP (32/37)
Functionality
The directional over-/under-power protection GOPPDOP (32)/GUPPDUP (37) can be
used wherever a high/low active, reactive or apparent power protection or alarming is
required. The functions can alternatively be used to check the direction of active or
Range or value
(0-100) %
>95%
(0.000-60.000) s
1MRK 502 048-UUS A
Accuracy
± 1.0% of I
n
-
± 0.5% ± 25 ms
Technical manual