Arcteq Generator Commander, Instruction Manual

Page: 248 / 561

Event block name Event names
IAE1 Start OFF
IAE1 Trip ON
IAE1 Trip OFF
IAE1 Block ON
IAE1 Block OFF
The function registers its operation into the last twelve (12) time-stamped registers. The register of the
function records the ON event process data for START, TRIP or BLOCKED. The table below
presents the structure of the function's register content.
Table. 5.4.25 - 220. Register content.
Date and time Event Phase current Phase voltage Used SG
dd.mm.yyyyhh:mm:ss.mss Event
name
Phase 1,2,3 [A,B,C]
currents
Phase AB, BC and CA
voltages
Setting group 1...8
active
5.4.26 Pole slip protection (78)
Pole slipping is a phenomena when synchronism is lost due to power swings. This can happen in
extreme fault conditions which cause a transient torque on the machine. Generators might experience
this if it has low excitation, because it produces a weak magnetic field. The "slip" occurs when rotor
electrically and physically shifts in relation to the stator, after which the field returns the rotor back in
sync with the stator. This causes high acceleration and deceleration causes stress on the generator
and prime mover, which can cause winding movement, shaft fracture or worse.
The pole slip protection function uses a total of eight (8) separate setting groups which can be selected
from one common source.
The operational logic consists of the following:
• input magnitude processing
• threshold comparator
• block signal check
• pole slip detection counter
• output processing.
The basic design of the protection function is the three-pole operation.
The inputs for the function are the following:
• setting parameters
• digital inputs and logic signals
• measured and pre-processed current and voltage magnitudes.
• calculated impedances
The function's outputs are START, TRIP and BLOCKED signals which can be used for direct I/O
controlling and user logic programming. The function generates general time-stamped ON/OFF events
to the common event buffer from each of the three (3) output signals. In the instant operating mode the
function outputs START and TRIP events simultaneously with an equivalent time stamp. The time stamp
resolution is 1 ms. The function also provides a resettable cumulative counter for the START, TRIP and
BLOCKED events.
Genera Generattor Commander or Commander
Instruction manual
Version: 2.07
246 © Arcteq Relays Ltd
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