Table of Contents
Advertisement
Functions
Differential current supervision − Block 13
5.5
5.5.1
Function description
5.5.2
Hints on setting
Differential current
supervision
Pick-up threshold
5-20
The 7SS60 also allows to supervise the external transformer circuits. The supervision
picks up when the threshold ,G WKU () is exceeded. This response comes
with a delay after the protection function.
The differential current supervision function is available in block 13. It has the task of
detecting malfunctions during operation and blocking so that they do not jeopardize
the stability of the system against external faults. This supervision function recognizes
transformer failures, e.g. due to phase failures, and sends an alarm. The differential
current supervision is able to block the protection if set before.
Figure 5-19
Release logic of the differential current supervision
The parameter ,G VXS () is used to activate and deactivate the differential
current supervision function. The following setting options are offered for the differen-
tial current supervision: blocking of the busbar protection till the release (EOUHO%3),
blocking till the acknowledgement (EODFN%3), or only output an alarm ($/50RQO\).
With 2)) the function can be deactivated.
In each measuring cycle, i.e. every 0.5 ms, it is checked whether the peak of the dif-
ferential current exceeds the threshold ,G 6XS taking into consideration
a hysteresis. In this case, the counter is increased by 1. Once the counter has reached
a value of 5000, the differential current supervision picks up. If no threshold was ex-
ceeded, the counter is reset to zero.
7SS60 Manual
E50417-G1176-C132-A2
Advertisement
Table of Contents
Troubleshooting
