Areva MiCOM P441, Technical Manual

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Relay Description P44x/EN HW/E33
MiCOM P441/P442 & P444 Page 5/44
1. RELAY SYSTEM OVERVIEW
1.1 Hardware overview
The relay hardware is based on a modular design whereby the relay is made up of several
modules which are drawn from a standard range. Some modules are essential while others
are optional depending on the user’s requirements.
The different modules that can be present in the relay are as follows:
1.1.1 Power supply module
The power supply module provides a power supply to all of the other modules in the relay, at
three different voltage levels. The power supply board also provides the RS485 electrical
connection for the rear communication port. On a second board the power supply module
contains relays which provide the output contacts.
1.1.2 Main processor board
The processor board performs most of the calculations for the relay (fixed and
programmable scheme logic, protection functions other than distance protection) and
controls the operation of all other modules within the relay. The processor board also
contains and controls the user interfaces (LCD, LEDs, keypad and communication
interfaces).
1.1.3 Co-processor board
The co-processor board manages the acquisition of analogue quantities, filters them and
calculates the thresholds used by the protection functions. It also processes the distance
algorithms.
1.1.4 Input module
The input module converts the information contained in the analogue and digital input signals
into a format suitable for the co-processor board. The standard input module consists of two
boards: a transformer board to provide electrical isolation and a main input board which
provides analogue to digital conversion and the isolated digital inputs.
1.1.5 Input and output boards
P441 P442 P444
Opto-inputs 8 x UNI(1) 16 x UNI(1) 24 x UNI(1)
Relay outputs 6 N/O
8 C/O
9 N/O
12 C/O
24 N/O
8 C/O
Universal voltage range opto inputs N/O – normally open
C/O – change over
1.1.6 IRIG-B board (P442 and P444 only)
This board, which is optional, can be used where an IRIG-B signal is available to provide an
accurate time reference for the relay. There is also an option on this board to specify a fibre
optic rear communication port, for use with IEC60870 communication only.
All modules are connected by a parallel data and address bus which allows the processor
board to send and receive information to and from the other modules as required. There is
also a separate serial data bus for conveying sample data from the input module to the
processor. figure 1 shows the modules of the relay and the flow of information between
them.