Introduction - REC 561
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1MRK 580 146-XEN
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Version 1.0-00
4.4 Pulse counter The normal use for this function is the counting of energy pulses for kWh
and kvarh in both directions from external energy meters. Up to 12 binary
inputs in a REC 561 can be used for this purpose with a frequency of up to
40 Hz. The number of pulses in the counter is then reported via the LON
bus to the station MMI or read via SPA as a service value.
4.5 Synchronism and
energizing check
The synchro-check function is used for controlled interconnection of a line in
an interconnected network. When used, the function gives an enable signal at
preset satisfactory conditions. The synchro-check function measures the dif-
ference between the line and busbar voltages, for the voltage (UDiff), phase
angle (PhaseDiff), and frequency (FreqDiff). It operates and permits clos-
ing of the circuit breaker when the set conditions are met.
The function can be used at manual closing and with the autoreclosing
function as a condition to be fulfilled before the breaker is closed.
4.6 Fuse failure
supervision
The operation of the built-in fuse failure supervision function is based on
the detection of a zero-sequence voltage without the presence of a zero
sequence current. The selection of operation, based on the presence of a
negative sequence voltage without the negative sequence current, is possi-
ble by means of settings. Its effect on the operation of the REC 561 is pro-
grammable in two ways: either by blocking the energizing function or the
loss of voltage protection, or by giving information on the fuse failure
only.
4.7 Multibreaker
autoreclosing
The reclosing function can be selected to perform single-phase and three-
phase reclosing from eight single-shot or multi-shot reclosing programs.
The three-phase autoreclose open time can be selected to give either high-
speed autoreclosing or delayed autoreclosing. Three-phase autoreclosing
can be performed with or without the use of the synchronism check or
energizing function.
Provision is included for co-operation between autoreclosing function
modules in the same terminal or between REC 561 terminals to achieve
sequential reclosing of the two breakers at a line end in a 1½-breaker,
double-breaker, or ring-bus arrangement.
One unit is defined as master; it recloses first. Should it be successful and
no trip occurs, the second module is released to complete the reclosing
sequence. For persistent faults, the breaker reclosing is limited to the first
breaker. Some connections between the function modules are required to
send signals and to release the autorecloser with low priority.
Up to six autoreclosing functions can be used in REC 561. Trip signals
from external protections start the autoreclosing functions and are con-
nected via binary inputs of the terminal.
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