Advertisement
5.2
Binary Outputs
Binary Outputs are mapped to output functions by means of settings. These could be used to bring out such
digital signals as trips, a general pick-up, plant control signals etc.
All Binary Outputs are Trip rated
Each can be defined as Self or Hand Reset. Self-reset contacts are applicable to most protection applications.
Hand-reset contacts are used where the output must remain active until the user expressly clears it e.g. in a
control scheme where the output must remain active until some external feature has correctly processed it.
Notes on Self Reset Outputs:
With a failed breaker condition the relay may remain operated until current flow in the primary system is
interrupted by an upstream device. The relay will then reset and attempt to interrupt trip coil current
flowing through an output contact. Where this level is above the break rating of the output contact an
auxiliary relay with heavy-duty contacts should be utilised.
©2014 Siemens Protection Devices Limited
Chapter 7) 7SR158 Applications Guide
Chapter 7) Page 23 of 24
Advertisement
