FANOX SIA D, User Manual, Page: 26 / 117

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SIA-D_
Rev. 07
26 / 117
ISO 9001:2008
4.7.2. Counter to register the number of openings
The SIA-D equipment is fitted with a counter that registers the number of times the circuit breaker
opens.
This meter is associated with the "Maximum number of openings" setting. When the number of
openings exceeds this preset value, the "Excessive number of openings" status is activated and its
corresponding event is generated.
This counter reading can be set to any value within its range from the HMI or by communications.
4.7.3. Accumulated amps counter: I2t
An accumulated amps counter is also fitted. This counter accumulates the amps that are cleared by
the circuit breaker by opening.
When the circuit breaker opens, the maximum number of primary amps in any of the phases is
detected. This reading is squared and divided by 1000 and then rescaled to KA and accumulated. If
the current detected in the opening is less than the rated current, the rated current value is used for
the accumulation.
It is used in conjunction with the metering of the number of openings, to measure the circuit breaker
aging process.
Since primary amps are being accumulated, it is essential to correctly adjust the phase CT
transformation ratio.
The "Maximum accumulated amps" setting is associated with this counter. When the number of
accumulated amps exceeds this preset value, the "Excessive accumulated amps" status is activated
and its corresponding event is generated.
This counter reading can be set to any value from within its range from the HMI or by
communications.
4.7.4. Excessive openings in a time window
As well as counting the number of times the circuit breaker opens, the SIA-D equipment sets up a
time window and the maximum number of openings allowed during this time. Both parameters can
be adjusted.
When this number is exceeded, the "Repeated Trips" status is activated and its corresponding event
is generated.
4.8. 67N1 and 67N2 Function. Neutral directional overcurrent protection
Two neutral directional overcurrent units are fitted: 67N1 and 67N2.
This function uses residual voltage as a polarisation variable and residual current as an operating
variable. The working range is defined in the following way: the operating angle is turned clockwise
based on the residual voltage to give the maximum torque direction. Over this maximum torque
direction, a cone is drawn with the adjusted semicone angle.
If the directional option is not activated, the 67N function behaves like a 50N function.
The actuation time is started when the following conditions are met simultaneously: