Controlling Protection Elements - Siemens 7SC80 Manual

•
If binary input 4602
input is active. If the binary input gets active while no trip command of (any) function applies, the auto-
matic reclosure function is blocked dynamically provided it is already running. Otherwise, there will be a
static blocking. The dead time is started if the binary input gets active following the trip command of a
starting element. An intermediate position of the circuit breaker cannot be detected for this type of allo-
cation.
•
If neither binary input 4602
cannot detect the position of the circuit breaker. In this case, the automatic reclosure function will be
controlled exclusively via pickups and trip commands. Monitoring for "52-b without TRIP" and starting the
dead time in dependence of the circuit breaker feedback is not possible in this case.
Circuit Breaker Monitoring
The time needed by the circuit breaker to perform a complete reclose cycle can be monitored by the 7SC80.
Breaker failure is detected:
A precondition for a reclosing attempt, following a trip command initiated by a protective relay element and
subsequent initiation of the automatic reclosing function, is that the circuit breaker is ready for at least one
TRIPCLOSE- TRIP cycle. The readiness of the circuit breaker is monitored by the device using a binary input
Ready . In the case where this signal from the breaker is not available, the circuit breaker monitoring feature
should be disabled, otherwise reclosing attempts will remain blocked.
•
Especially when multiple reclosing attempts are programmed, it is a good idea to monitor the circuit
breaker condition not only prior to the first but also to each reclosing attempt. A reclosing attempt will be
blocked until the binary input indicates that the circuit breaker is ready to complete another CLOSE-TRIP
cycle.
•
The time needed by the circuit-breaker to regain the ready state can be monitored by the 7SC80. The
monitoring time CB TIME OUT expires for as long as the circuit breaker does not indicate that it is ready
via binary input
monitoring time CB TIME OUT is started. If the binary input returns before the monitoring time has
elapsed, the monitoring time will be canceled and the reclosure process is continued. If the monitoring
time runs longer than the dead time, the dead time will be extended accordingly. If the monitoring time
elapses before the circuit breaker signals its readiness, the automatic reclosure function will be blocked
dynamically.
The time 7114 T-Start MONITOR serves for monitoring the response of the automatic reclosure function to
a breaker failure. It is activated by a trip command arriving before or during a reclosing operation and marks
the time that passes between tripping and opening of the circuit breaker. If the time elapses, the device
assumes a breaker failure and the automatic reclosure function is blocked dynamically. If parameter T-Start
MONITOR is set to T-Start MONITOR, the start monitoring is disabled.

Controlling Protection Elements

2.14.4
The automatic reclosing function can influence delay times and threshold values of the directional and nondir-
ectional time overcurrent protection (control of protection elements). There are three mechanisms:
•
The time overcurrent elements can trip instantaneously depending on the automatic reclosure cycle (T =
0), they can remain unaffected by the automatic reclosing function (T = T) or they can be blocked (T = ∞).
For further information see margin heading "Cyclic Control".
•
The automatic reclosing states "AR ready" and "AR not ready" can activate or deactivate the dynamic cold
load pickup function. This function allows the threshold values and trip delays of the overcurrent protec-
tion elements to be switched (see also Section
Pickup).
•
The time overcurrent protection parameter 1X14A 50(N)-2 ACTIVE or 1X16A 50(N)-3 ACTIVE defines
whether the 50(N)-2 or 50(N)-3 elements always operate or only with "79 Auto Reclosing ready"(see
Section 2.2 Overcurrent Protection 50, 51, 50N,
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
>52-b alone is allocated, the circuit breaker is considered open while the binary
>52-b nor 4601 >52-a are allocated, the automatic reclosure program
>CB Ready (FNo. 2730). That means if the binary input >CB Ready is cleared, the
2.14 Automatic Reclosing System 79
2.14.6 Setting Notes and Section
51N).
Functions
>CB
2.4 Dynamic Cold Load
275