Counters - ABB RELION REX640 Technical Manual

Section 9
Control functions
9.9.5
9.9.6
1520
• Frq Op counter limit
• Frq Op counter time
• Frq Op recovery time
The Frq Op counter limit setting defines the number of reclose attempts that are
allowed during the time defined with the Frq Op counter time setting. If the set value
is reached within a pre-defined period defined with the Frq Op counter time setting,
the AR function goes to lockout when a new shot begins, provided that the counter is
still above the set limit. The lockout is released after the recovery time has elapsed.
The recovery time can be defined with the Frq Op recovery time setting .
If the circuit breaker is manually closed during the recovery time, the reclaim time is
activated after the recovery timer has elapsed.

Counters

The AR function contains six counters. Their values are stored in a semi-retain
memory. The counters are increased at the rising edge of the reclosing command. The
counters count the following situations.
• COUNTER: counts every reclosing command activation
• CNT_SHOT1: counts reclosing commands that are executed from shot 1
• CNT_SHOT2: counts reclosing commands that are executed from shot 2
• CNT_SHOT3: counts reclosing commands that are executed from shot 3
• CNT_SHOT4: counts reclosing commands that are executed from shot 4
• CNT_SHOT5: counts reclosing commands that are executed from shot 5
The counters are disabled through communication with the DsaCnt parameter. When
the counters are disabled, the values are not updated.
The counters are reset through communication with the CntRs parameter. The same
functionality can also be found in the clear menu (DARREC1 counters).
Application
Modern electric power systems can deliver energy to users very reliably. However,
different kind of faults can occur. Protection relays play an important role in detecting
failures or abnormalities in the system. They detect faults and give commands for
corresponding circuit breakers to isolate the defective element before excessive
damage or a possible power system collapse occurs. A fast isolation also limits the
disturbances caused for the healthy parts of the power system.
The faults can be transient, semi-transient or permanent. Permanent fault, for example
in power cables, means that there is a physical damage in the fault location that must
first be located and repaired before the network voltage can be restored.
In overhead lines, the insulating material between phase conductors is air. The
majority of the faults are flash-over arcing faults caused by lightning, for example.
1MRS759142 C
REX640
Technical Manual