Application Guide - NP900 Series
64 (504
)
A996A
Date & Time
Event
code
Fault
type
Trigger
current
Fault
current
Prefault
current
Trip time
remaining
Used
SG
dd.mm.yyyy
hh:mm:ss.mss
1280-
1477
Descr.
L1-G…
L1-L2-
L3
Start
average
current
Trip
-20 ms
averages
Start
-200 ms
averages
0 ms -
1800 s
1 - 8
3.2.3
N
ON
-
DIRECTIONAL EARTH FAULT
I0>
(50N/51N)
Non directional earth fault function (NEF) is used for instant- and time delayed earth fault
protection for various applications including feeder, filter and machine applications of
utilities and industry. The number of available instances of the function depends of the
IED model. Function measures constantly selected neutral current magnitudes which on
the operating decisions are based. Monitored phase current magnitudes can be selected
fundamental component RMS, TRMS values (including harmonics up to 32
nd
) or peak-to-
peak values of residual current measurement inputs I01 and I02 or from phase current
measurements calculated zero sequence current I0Calc. Blocking signal and setting
group selection controls the operating characteristics of the function during normal
operation.
Outputs of the function are Start Trip and Blocked signals. Setting parameters are static
inputs for the function which are changed only by user input in the setup phase of the
function. Non directional overcurrent function utilizes total of eight separate setting groups
which can be selected from one common source.
The function can be operating on instant or time delayed mode. In time delayed mode the
operation can be selected for definite time or IDMT. For IDMT operation IEC and ANSI
standard time delays are supported as well as custom parameters. Function includes
saturation checking which allows the function to start and operate accurately also in case
of CT saturation condition.
The operational logic consists of input magnitude processing, input magnitude selection,
saturation check, threshold comparator, block signal check, time delay characteristics and
output processing.
Inputs for the function are the operating mode selections, setting parameters and
measured and pre-processed current magnitudes and binary input signals. Function
outputs START, TRIP and BLOCKED signals which can be used for direct IO controlling
and also for user logic programming. The function registers its operation into 12 last time-
stamped registers and also generates general time stamped ON/OFF events to the
Содержание NP900 Series
Страница 1: ......
Страница 49: ...Application Guide NP900 Series 49 504 A996A Figure 3 2 1 3 25 Definite time operating characteristics...
Страница 50: ...Application Guide NP900 Series 50 504 A996A Figure 3 2 1 3 26 IEC predefined characteristics NI VI LTI and EI...
Страница 52: ...Application Guide NP900 Series 52 504 A996A Figure 3 2 1 3 28 IEEE predefined characteristics EI MI and VI...
Страница 243: ...Application Guide NP900 Series 243 504 A996A Figure 3 3 2 1 122 NPS biased thermal trip curves with kNPS values 7 and 10...
Страница 491: ...Application Guide NP900 Series 491 504 A996A 3 7 5 6 SETTING EXAMPLE...
Страница 504: ...Application Guide NP900 Series 504 504 A996A A996A...