Event number
Event channel
Event block name
Event code
Description
8449
132
VUB3
1
Start OFF
8450
132
VUB3
2
Trip ON
8451
132
VUB3
3
Trip OFF
8452
132
VUB3
4
Block ON
8453
132
VUB3
5
Block OFF
8512
133
VUB4
0
Start ON
8513
133
VUB4
1
Start OFF
8514
133
VUB4
2
Trip ON
8515
133
VUB4
3
Trip OFF
8516
133
VUB4
4
Block ON
8517
133
VUB4
5
Block OFF
The function registers its operation into the last twelve (12) time-stamped registers; this information is
available for all provided instances separately. 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. 5.3.13 - 129. Register content.
Date and time
Event code
Trigger
voltage
Fault
voltage
Pre-fault
voltage
Trip time
remaining
Used SG
dd.mm.yyyy
hh:mm:ss.mss
8320 -
8517 Descr.
Start average
voltage
Trip -20ms
averages
Start -200ms
averages
0 ms...1800s
Setting
group 1...8 active
5.3.14 Volts-per-hertz overexcitation protection (V/Hz>; 24)
Generators, transformers, and motors have their own, specific volts-per-hertz ratios under which these
machines are expected to operate. Exceeding the V/Hz ratio results in machine overexcitation which
causes iron core saturation in generators and transformers. This causes a breakdown of the insulation
in the core's interlamination due to excessive voltage and eddy current heating. Additionally, stray flux
is induced into non-laminated components which are not designed to carry flux-caused currents. In
generators overexcitation typically occurs if the V/Hz ratio goes five percent above the nominal V/Hz
ratio, with any possible damage happening within seconds. The most common situation for
overexcitation is when a machine is off-line prior to synchronization.
The figure below shows how the pick-up settings and the measured frequency affect the pick-up level
of the volts-per-hertz protection function.
A
AQ
Q-T215
-T215
Instruction manual
Version: 2.04
194