MSCDN – MP2A Description of Operation
•
Change of state of Output Relays.
•
Change of state of Status Inputs.
•
Change of Settings and Settings Group
•
Change of state of any of the control functions of the relay.
4.2.4 Fault Recording
The led flag configuration, date and time of the last five faults are recorded for display via the Fascia
LCD.
Note: the real-time clock, waveform records and event records are all maintained, in the event of loss of
auxiliary D.C. supply voltage, by the backup storage capacitor. This capacitor has the ability to maintain
the charges on the real-time clock IC and the SRAM memory device for typically 2-3 weeks time
duration. This time, however, is influenced by factors such as temperature and the age of the capacitor
and could be shorter.
4.3 Time Synchronisation
Time and date can be set either via the relay fascia using appropriate commands in the System Config
menu or via an IRIG-B input or via the communications interface
4.3.1 IRIG-B Time Synchronisation
A BNC connector on the relay rear provides an isolated IRIG-B GPS time synchronisation port. The
IRIG-B input expects an modulated 3-6 Volt signal and provides time synchronisation to the nearest
millisecond.
4.3.2 IEC 60870-5-103 Time Synchronisation
Relays connected individually or in a ring or star configuration can be directly time synchronised using
the IEC 60870-5-103 global time synchronisation. This can be from a dedicated substation automation
system or from Reydisp Evolution Communications Support Software.
4.3.3 Real Time Clock Time Synchronisation
In the absence of IRIG-B and IEC60870 time synchronisation the relay contains a year 2000 compatible
real time clock circuit which maintains real time in the absence of DC supply (See Note).
4.4 Communications
Two fibre optic communication ports, COM 1 and COM 2b are provided at the rear of the relay, which give
superior EMC performance. An isolated RS232 port, COM 2a is provided at the front of the relay for local
access using a PC.
Communication is compatible with the IEC870-5-103 FT 1.2 transmission and application standards. For
communication with the relay via a PC (personal computer) a user-friendly software package, REYDISP
EVOLUTION, is available to allow transfer of the following:
Relay Settings
Waveform Records
Event Records
Fault Data Records
Instrument and meters
Control Functions
Communications operation is described in detail in Section 4 of this manual. For information about all
aspects of the communications protocol used in the Modular II range of relays see [2].
4.5 Settings Groups
Depending upon the relay model then up to four alternative setting groups are provided, making it possible
to edit one group while the relay protection algorithms operate using another ‘active’ group. An indication of
which group is being viewed is given by the ‘Gn’ character in the top left of the display. Settings that do not
indicate Gn in the top left corner of the LCD are common to all groups.
©2010 Siemens Protection Devices Limited
Chapter 1 Page 7 of 13
