P44x/EN AP/Hb
MiCOM P40 Agile P442, P444
(AP) 5-
5.5.2 Control I/P Configuration
The “CTRL I/P CONFIG” column has several functions one of which allows the user to
configure the control inputs as either ‘latched’ or ‘pulsed’. A latched control input will remain
in the set state until a reset command is given, either by the menu or the serial
communications. A pulsed control input, however, will remain energised for 10ms after the
set command is given and will then reset automatically (i.e. no reset command required).
In addition to the latched / pulsed option this column also allows the control inputs to be
individually assigned to the “Hotkey” menu by setting ‘1’ in the appropriate bit in the “Hotkey
Enabled” cell. The hotkey menu allows the control inputs to be set, reset or pulsed without
the need to enter the “CONTROL INPUTS” column. The “Ctrl Command” cell also allows the
SET / RESET text, displayed in the hotkey menu, to be changed to something more suitable
for the application of an individual control input, such as “ON / OFF”, “IN / OUT” etc.
5.5.3 Control I/P Labels
The “CTRL I/P LABELS” column makes it possible to change the text associated with each
individual control input. This text will be displayed when a control input is accessed by the
hotkey menu, or it can be displayed in the PSL.
Note: With the exception of pulsed operation, the status of the control inputs is stored in
battery backed memory. In the event that the auxiliary supply is interrupted the status
of all the inputs will be recorded. Following the restoration of the auxiliary supply the
status of the control inputs, prior to supply failure, will be reinstated. If the battery is
missing or flat the control inputs will set to logic 0 once the auxiliary supply is restored
5.6 InterMiCOM Teleprotection
InterMiCOM is a protection signalling system that is an optional feature of MiCOM Px40
relays and provides a cost-effective alternative to discrete carrier equipment. InterMiCOM
sends eight signals between the two relays in the scheme, with each signal having a
selectable operation mode to provide an optimal combination of speed, security and
dependability in accordance with the application. Once the information is received, it may be
assigned in the Programmable Scheme Logic to any function as specified by the user’s
application.
5.6.1 Protection Signalling
To achieve fast fault clearance and correct discrimination for faults anywhere within a high
voltage power network, it is necessary to signal between the points at which protection
relays are connected. Two distinct types of protection signalling can be identified:
5.6.1.1 Unit protection Schemes
In these schemes the signalling channel is used to convey analog data concerning the power
system between relays, typically current magnitude and/or phase. These unit protection
schemes are not covered by InterMiCOM, with the MiCOM Px4x range of current differential
and phase comparison relays available.
5.6.1.2 Teleprotection – Channel Aided Schemes
In these schemes the signalling channel is used to convey simple ON/OFF data (from a local
protection device) thereby providing some additional information to a remote device which
can be used to accelerate in-zone fault clearance and/or prevent out-of-zone tripping. This
kind of protection signalling has been discussed earlier in this chapter, and InterMiCOM
provides the ideal means to configure the schemes in the P443 relay.
In each mode, the decision to send a command is made by a local protective relay operation,
and three generic types of InterMiCOM signal are available:
Intertripping In intertripping (direct or transfer tripping applications), the command is not
supervised at the receiving end by any protection relay and simply causes CB
operation. Since no checking of the received signal by another protection
device is performed, it is absolutely essential that any noise on the signalling
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