MSCDN – MP2A Description of Operation
3.3 Trip Circuit Supervision
Status inputs on the relay can be used to supervise trip circuits while the associated circuit breakers (CB)
are either open or closed. Since the status inputs can be programmed to operate output contacts and
LED’s, alarms can be also generated from this feature.
To use the function set ‘Trip Cct Pickup Delay to the required value in the Reylogic Elements Menu and
then map the ‘Trip Circuit Fail’ settings in the Output Relay Menu and LED Menu as required.
See the Applications Guide for more details on the trip circuit supervision scheme.
4 Other Features
4.1 Metering
The metering feature provides real-time data available from the relay fascia in the ‘Instruments Mode’ or
via the communications interface.
The following displays are available:
RMS Resistor currents (primary and nominal)
RMS Resistor Open Circuit currents (nominal difference between R1 & R2)
Digital input status
Output relay status
Time and Date
4.2 Data Storage
4.2.1 General
Details of relay operation are recorded in three forms, namely Waveform records, Event records and
Fault Data records. All records are time and date stamped with a resolution of one millisecond.
4.2.2 Waveform Records.
The waveform record feature stores analogue and digital information for the current inputs, status inputs
and output relays and LED’s.
The waveforms are stored with a sampling resolution of 16 samples per cycle. The waveform recorder
has the ability to store records for the previous four trip operations of the relay. These are labelled 1-4
with 1 being the most recent record. This however, can be altered using the ‘Record Duration’ setting,
which offers the following selection:
•
Four records of one-second duration.
•
Two records of two seconds duration.
•
One record of five seconds duration.
The waveform recorder will be triggered automatically when any protection element operates. It can also
be triggered by any of the following means:
•
The ‘Trigger Storage” status input signal.
•
The IEC870-5-103 communications interface.
The waveform recorder has a settable pre-fault triggering capability.
4.2.3 Event Records
The event recorder feature allows the time tagging of any change of state (Event) of the relay. As an
event occurs the actual event condition is logged as a record along with a time and date stamp to a
resolution of 1 millisecond. There is capacity for a maximum of 500 event records that can be stored in
the relay and when the event buffer is full any new record will over-write the oldest. The following events
are logged:
©2010 Siemens Protection Devices Limited
Chapter 1 Page 6 of 13
