Setting Notes - Siemens SIPROTEC 4 7VK61 Manual

[funktionsschema-endfehlerschutz-wlk-010802, 1, en_GB]
Figure 2-45
Pole discrepancy supervision
The pole discrepancy supervision has the task to detect discrepancies in the position of the three circuit
breaker poles. Under steady-state operating conditions, either all three poles of the circuit breaker must be
closed, or all three poles must be open. Discrepancy is permitted only for a short time interval during a 1-pole
automatic reclose cycle.
Figure 2-46 the functional principle. The signals which are processed here are the same as those used for the
circuit breaker failure protection. The pole discrepancy condition is established when at least one pole is
closed (" ≥ one pole closed") and at the same time not all three poles are closed (" ≥ one pole open").
Additionally, the current criteria (from
current is not flowing through all three poles, i.e. through only one or two poles. When current is flowing
through all three poles, all three poles must be closed even if the circuit breaker auxiliary contacts indicate a
different status.
Detection of the discrepancy of the CB poles is signaled phase-selective as "Pickup". The signal identifies the
pole that was open before the trip command of the pole discrepancy supervision occurred.
[logikschema-schalt-gleichlfueberwch-wlk-010802, 1, en_GB]
Figure 2-46

Setting Notes

2.6.2
General
The circuit breaker failure protection and its ancillary functions (end fault protection, pole discrepancy supervi-
sion) can only operate if they were set during configuration of the scope of functions (address 139 BREAKER
FAILURE) to Enabled or enabled w/ 3I0>.
Circuit breaker failure protection
The circuit breaker failure protection is switched ON or OFF at address 3901 FCT BreakerFail.
The current threshold I> BF (address 3902) should be selected such that the protection will operate with the
smallest expected short-circuit current. A setting of 10% below the minimum fault current for which circuit
breaker failure protection must operate is recommended. On the other hand, the value should not be set
lower than necessary.
SIPROTEC 4, 7VK61, Manual
C53000-G1176-C159-5, Edition 05.2018
Functional scheme of the end fault protection
Figure
Function diagram of pole discrepancy supervision
2.6 Circuit breaker failure protection (optional)
2-33) are processed Pole discrepancy can only be detected when
Functions
125