1MRS752308-MUM NEF1_

Issued: 10/1997
Version: F/03.05.2002
Non-Directional
Earth-Fault Protection
Low-Set Stage (NEF1Low)
High-Set Stage (NEF1High)
Data subject to change without notice Instantaneous Stage (NEF1Inst)

Contents
1. Introduction .............................................................................................. 2
1.1 Features.............................................................................................. 2
1.2 Application........................................................................................... 2
1.3 Input description.................................................................................. 3
1.4 Output description ............................................................................... 3
2. Description of operation .......................................................................... 4
2.1 Configuration....................................................................................... 4
2.2 Measuring mode ................................................................................. 4
2.3 Operation criteria................................................................................. 4
2.4 Delayed reset facility and drop-off time in DT and IDMT modes.......... 5
2.5 IDMT type operation of NEF1Low ....................................................... 6
2.5.1 Standard curve groups ............................................................... 7
2.5.2 RI curve groups.......................................................................... 8
2.5.3 RD curve groups ........................................................................ 8
2.5.4 IEEE curve groups ..................................................................... 9
2.6 Setting groups ..................................................................................... 9
2.7 Test mode ......................................................................................... 10
2.8 START, TRIP and CBFP outputs ...................................................... 10
2.9 Resetting........................................................................................... 11
3. Parameters and events .......................................................................... 12
3.1 General ............................................................................................. 12
3.2 Setting values.................................................................................... 13
3.2.1 Actual settings.......................................................................... 13
3.2.2 Setting group 1......................................................................... 14
3.2.3 Setting group 2......................................................................... 15
3.2.4 Control settings ........................................................................ 16
3.3 Measurement values ......................................................................... 18
3.3.1 Input data ................................................................................. 18
3.3.2 Output data .............................................................................. 19
3.3.3 Recorded data.......................................................................... 19
3.3.4 Events ...................................................................................... 24
4. Technical data ........................................................................................ 25
 NEF1_ Substation Automation

1. Introduction

1.1 Features

• Non-directional earth-fault protection

• Definite-time (DT) operation
• NEF1Low: fourteen inverse-time (IDMT) characteristics
• Neutral current measurement with a conventional current transformer
• Two alternative measuring principles: the average value of consecutive
instantaneous peak-to-peak values or the numerically calculated fundamental
frequency component of the earth-fault current
• Integrated circuit-breaker failure protection (CBFP) function

1.2 Application

This document specifies the functions of the non-directional earth-fault protection

function blocks NEF1Low, NEF1High and NEF1Inst used in products based on the
RED 500 Platform. The inverse-time operation is only included in the low-set stage
(NEF1Low).

The non-directional earth-fault protection function blocks are designed for non-
directional earth-fault protection whenever the DT characteristic or, as concerns
NEF1Low, the IDMT (Inverse Definite Minimum Time) characteristic is appropriate.
Suppression of harmonics is possible.

Io> Io>> Io>>>

CBFP CBFP CBFP

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 Substation Automation NEF1_

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1.3 Input description

Name Type Description

Io Analogue signal (SINT) Input for measuring neutral current I0
BS1 Digital signal (BOOL, active Blocking signal 1
high)
BS2 Digital signal (BOOL, active Blocking signal 2
high)
TRIGG Digital signal (BOOL, pos. Control signal for triggering the
edge) registers
GROUP Digital signal (BOOL, active Control input for switching between the
high) setting groups 1 and 2. When GROUP
is FALSE, group 1 is active. When
GROUP is TRUE, group 2 is active.
BSREG Digital signal (BOOL, active Input for blocking the recording function
high)
RESET Reset signal (BOOL, pos. Input signal for resetting the trip signal
edge) and registers of NEF1Low, NEF1High
or NEF1Inst

1.4 Output description

Name Type Description

START Digital signal (BOOL, active high) Start signal
TRIP Digital signal (BOOL, active high) Trip signal
CBFP Digital signal (BOOL, active high) Delayed trip signal for circuit-
breaker failure protection (CBFP)
ERR Digital signal (BOOL, active high) Signal for indicating a
configuration error

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 NEF1_ Substation Automation

2. Description of operation

2.1 Configuration

Neutral current I0 can be measured with a conventional current transformer. If the

neutral of the network is either isolated or earthed by a high impedance, a core
balance current transformer is recommended to be used in earth fault protection. To
ensure sufficient accuracy of neutral current measurements and consequently the
selectivity of the scheme, core balance current transformers should have a
transformation ratio of at least 70:1. Lower transformation ratios like 50:1 or 50:5 are
not recommended.

The measuring devices and signal types for analogue channels are selected and
configured in a special dialogue box of the Relay Configuration Tool included in the
CAP 505 Tool Box. Digital inputs are configured in the same programming
environment (the number of selectable analogue inputs, digital inputs and digital
outputs depends on the type of the hardware used).

When the analogue channels and digital inputs have been selected and configured in
the dialogue box, the inputs and outputs of the function block can be configured on a
graphic worksheet of the configuration tool. The neutral current I0 can be connected to
the Io input of the function block. Furthermore, digital inputs are connected to the
Boolean inputs of the function block and in the same way, the outputs of the function
block are connected to the output signals.

2.2 Measuring mode

The operation of the function block is based on two alternative measuring principles:
the average value of consecutive instantaneous peak-to-peak values or the numerically
calculated fundamental frequency component of the neutral current. The measuring
mode is selected by means of an HMI parameter or a serial communication parameter.

With both the measuring principles, the operation is insensitive to the DC component
and the operation accuracy is defined in the frequency range f/fn=0.95...1.05. In peak-
to-peak measurement, the harmonics of the neutral current are not suppressed,
whereas in fundamental frequency measurement the harmonics suppression is at least
-50 dB at f = n x fn, where n = 2, 3, 4, 5,...

2.3 Operation criteria

The function block starts if the neutral current exceeds the set start current. When the
function block starts, the START signal is set to TRUE. Should the duration of the
earth fault exceed the set definite operate time or, at the inverse-time operation, the
time determined by the level of the measured current, the function block operates. The

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 Substation Automation NEF1_

internal delay of the heavy-duty output relay is included in the total operate time.
When the function block operates, the TRIP signal is set to TRUE. Operation mode
instantaneous is selectable in the function blocks NEF1High and NEF1Inst. In
instantaneous mode the TRIP signal is immediately activated.

The DT or IDMT timer is allowed to run only if the blocking signal BS1 is inactive,
i.e. its value is FALSE. When the signal becomes active, i.e. its value turns to TRUE,
the timer will be stopped (frozen).

When the blocking signal BS2 is active, the TRIP signal cannot be activated. The
TRIP signal can be blocked by activating the signal BS2 until the function block
drops off.

2.4 Delayed reset facility and drop-off time in DT and IDMT modes

The purpose of the delayed reset function is to enable fast clearance of intermittent
faults, e.g. self-sealing insulation faults, and severe faults which may produce high
asymmetrical fault currents that partially saturate the current transformers. It is typical
for an intermittent fault that the fault current contains so-called drop-off periods
during which the fault current is below the set start current. Without the delayed reset
function the DT or the IDMT timer would reset once the current drops off. In the
same way, an apparent drop-off period of the secondary current of the saturated
current transformer might reset the DT or the IDMT timer. The adjustable delayed
reset function also enables closer co-ordination with electromechanical induction disc
relays.

When the DT timer has started, it goes on running normally even if the current drops
off, provided the drop-off period is shorter than the set drop-off time. In the same
situation, the IDMT timer is frozen. If the drop-off period is longer than the set drop-
off time, the DT or the IDMT timer will be reset when the drop-off time elapses. The
situation in the case of the DT timer is described in Figure 2.4.-1.

In Figures 2.4.-1 and 2.4.-2 the input signal IN of the DT timer is TRUE when the
current is above the set start value and FALSE when the current is below the set start
value.

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 NEF1_ Substation Automation

1
IN
0

START

TRIP

Drop-off time
Drop-off
timer

Dropoff1.fh7
Operate time
Operate
timer

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If the drop-off period is shorter than the set drop-off time and the DT timer time has
elapsed during the drop-off period, the function block will trip once the current
exceeds the set value again (Figure 2.4.-2).

1
IN
0

START

TRIP

Drop-off time
Drop-off
timer
Dropoff2.fh7

Operate time
Operate
timer

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2.5 IDMT type operation of NEF1Low

In the inverse-time mode, the operate time of the stage is a function of the current.
The higher the current, the shorter the operate time is. Fourteen time/current curve
groups are available. Four of the groups comply with the BS 142 and IEC 60255
standards, whereas the two curve groups RI and RD (RXIDG) are special type of
curve groups corresponding to the ABB praxis. Eight IEEE curves comply with the
IEEE C37.112 standard. The setting "Operation mode" is used for selecting the
desired operate time characteristic.

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 Substation Automation NEF1_

The shortest operate time at the inverse-time operation is limited by a special

adjustable minimum time located in control settings. The definite minimum time will
not allow operate times shorter than the set minimum time, which is why the inverse-
time mode is called the IDMT mode (Inverse Definite Minimum Time).

2.5.1 Standard curve groups

The four internationally standardized inverse-time characteristics incorporated in the

inverse-time operation of the function are:

• normal inverse (NI)

• very inverse (VI)
• extremely inverse (EI)
• long-time inverse (LI)
(For a graphical presentation of the curves, refer to the manual Technical Descriptions
of Functions, Introduction.)

The relationship between time and current is in accordance with the standard IEC
60255-4 and can be expressed as follows

kxβ
t[s] =
I α
( ) −1
I>
where

t operate time in seconds

k adjustable time multiplier, parameters S4, S44 and S74

I phase current

I> adjustable start current, parameters S2, S42 and S72

α, β constants to provide selected curve characteristics

The values of the constants a and b determine the slope as follows

Inverse-time α β
characteristic
Normal inverse 0.02 0.14
Very inverse 1.0 13.5
Extremely inverse 2.0 80.0
Long-time inverse 1.0 120

According to the standard BS 142: 1966 the effective current range is defined as
2...20 times the set start current. If the time/current characteristic is normal inverse,

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 NEF1_ Substation Automation

very inverse or extremely inverse, the function has to start at the latest when the
current exceeds the set start current by 1.3 times. For the long-time inverse
characteristic, the effective current range is specified to be 2...7 times the set start
current and the relay is to start at the latest when the current exceeds the setting value
by 1.1 times. The function block NEF1Low will start and the IDMT integration will
begin once the current exceeds the set start current.

The operate time tolerances specified by the standard BS 142 : 1966 are the following
(E denotes the accuracy in percent):

I/I > Normal Very Extremely Long time

2 2.22E 2.34E 2.44E 2.34E
5 1.13E 1.26E 1.48E 1.26E
7 - - - 1.00E
10 1.01E 1.01E 1.02E -
20 1.00E 1.00E 1.00E -

The tolerance factors are in accordance to those defined by the standard BS 142: 1966
for currents 2 and 5 times the setting. The NEF1Low complies with the tolerances of
class 5 (E = 5.0%) for all inverse-time curves.

For example:

I/I>= 10, characteristic = Normal

Operate time tolerance = 1.01 x 5.0% = 5.05%

2.5.2 RI curve groups

The RI-type inverse-time characteristic is a special characteristic mainly used to

obtain time grading with mechanical relays. The characteristic can be expressed as
follows:

k
t s =
I>
0. 339 − 0. 236 x
I

2.5.3 RD curve groups

The RD-type characteristic is a special characteristic mainly used in earth-fault

protection where a high degree of selectivity is required also at high-resistance faults.
Mathematically, the characteristic can be expressed as follows:

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 Substation Automation NEF1_

I
t[s] = 5. 8 -1. 35 x ln
k x I>
The accuracy of the RI- and RD-type characteristics is 5%. Also with the RI- and RD-
type characteristics, the function block will start and the IDMT integration will begin
once the current exceeds the set start current.

2.5.4 IEEE curve groups

IEEE time overcurrent curve equation according to the standard IEEE C37.112:

 
 
 $ 
t[s] =  3
+ % × Q
  ,  − 1 
 ,> 
  

where

I> adjustable start current, parameters S2, S42 and S72

n adjustable IEEE time dial setting, parameters S5, S45 and S75

A, B, p constants to provide selected curve characteristics

Curve A B p
IEEE Extremely Inverse 6.407 0.025 2.0
IEEE Very Inverse 2.855 0.0712 2.0
IEEE Inverse 0.0086 0.0185 0.02
IEEE Short Time Inverse 0.00172 0.0037 0.02
IEEE Short Time Ext. Inverse 1.281 0.005 2.0
IEEE Long Time Ext. Inv. 64.07 0.250 2.0
IEEE Long Time Very Inv. 28.55 0.712 2.0
IEEE Long Time Inverse 0.086 0.185 0.02

2.6 Setting groups

Two different groups of setting values, group 1 and group 2, are available for the
function block. Switching between the two groups can be done in the following three
ways:

1 Locally via the control parameter “Group selection”1) of the HMI

2 Over the serial bus with the command V31)

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 NEF1_ Substation Automation

3 By means of the input signal GROUP when allowed via the parameter “Group
selection” (i.e. when V3 = 21)).
1)
Group selection (V3): 0 = Group 1; 1 = Group 2; 2 = GROUP input

The group settings come into effect immediately after selection. The control
parameter "Active group" indicates that the setting group is valid at a given time.

2.7 Test mode

The digital outputs of the function block can be activated with separate control
settings for each output either locally via the HMI or externally via the serial
communication. When an output is activated with the test parameter, an event
indicating the test is generated.

The protection functions operate normally while the outputs are tested.

2.8 START, TRIP and CBFP outputs

The output signal START is always pulse-shaped. The minimum pulse width of the
corresponding output signal is set via a separate parameter on the HMI or on serial
communication. If the start situation is longer than the set pulse width, the START
signal remains active until the start situation is over. The output signal TRIP may
have a non-latching or latching feature. When the latching mode has been selected,
the TRIP signal remains active until the output is reset even if the operation criteria
have reset.

The circuit-breaker failure protection function provides a delayed trip signal CBFP
after the TRIP signal unless the fault has disappeared during the set CBFP time delay.
The CBFP output can be used to operate a circuit breaker in front of the circuit
breaker of the feeder. The control parameter “Trip pulse” also sets the pulse width of
the CBFP output signal.

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2.9 Resetting

The TRIP output signal and the registers can be reset either via the RESET input, or
over the serial bus or the local HMI.

The operation indicators, latched trip signal and recorded data can be reset as follows:

Operation Latched trip Recorded

indicators signal data
1)
RESET input of the function block X X
1)
Parameter F038V013 for NEF1Low X X
1)
Parameter F039V013 for NEF1High X X
1)
Parameter F090V013 for NEF1Inst X X
2)
General parameter F001V011 X
2)
General parameter F001V012 X X
2)
General parameter F001V013 X X X
2)
Push-button C X
2)
Push-buttons C + E (2 s) X X
2)
Push-buttons C + E (5 s) X X X
1)
Resets the latched trip signal and recorded data of the particular function block.
2)
Affects all function blocks.

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 NEF1_ Substation Automation

3. Parameters and events

3.1 General

• Each function block has a specific channel number for serial communication
parameters and events. The channel for NEF1Low is 38, that for NEF1High 39 and
that for NEF1Inst 90.
• The data direction of the parameters defines the use of each parameter as follows:
Data direction Description
R, R/M Read only
W Write only
R/W Read and write

• The different event mask parameters (see section “Control settings”) affect the
visibility of events on the HMI or on serial communication (LON or SPA) as
follows:
Event mask 1 (FxxxV101/102) SPA / HMI (LON)
Event mask 2 (FxxxV103/104) LON
Event mask 3 (FxxxV105/106) LON
Event mask 4 (FxxxV107/108) LON

For example, if only the events E3, E4 and E5 are to be seen on the HMI of the
relay terminal, the event mask value 56 (8 + 16 + 32) is written to the “Event mask
1” parameter (FxxxV101).
In case a function block includes more than 32 events, there are two parameters
instead of e.g. the “Event mask 1” parameter: the parameter “Event mask 1A”
(FxxxV101) covers the events 0...31 and “Event mask 1B”(FxxxV102) the events
32...63.

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3.2 Setting values

3.2.1 Actual settings

NEF1Low

Parameter Code Values Unit Default Data Explanation

direction
Operation mode S1 0 ... 15 1) - 1 R Selection of operation mode
and inverse-time
characteristic

Start current S2 1.0...100.0 % In 1.0 R Start current

Operate time S3 0.05...300.00 s 0.05 R Operate time in DT mode

Time multiplier S4 0.05...1.00 - 0.05 R Time multiplier ‘k’ in IDMT

mode

IEEE time dial S5 0.5...15.0 - 0.5 R IEEE time dial ‘n’ in IDMT
mode
1)
Operation mode 0 = Not in use; 1 = Definite time; 2 = Extremely inv.; 3 = Very inv.;
4 = Normal inv.; 5 = Long-time inv.; 6 = RI-type inv.; 7 = RD-type inv.; 8 =
IEEE Ext.; 9 = IEEE Very inv.; 10 = IEEE Inverse; 11 = IEEE S.T. inv.; 12 =
IEEE S.T.E. inv; 13 = IEEE L.T.E. inv.; 14 = IEEE L.T.V. inv.; 15 = IEEE L.T.
inv.

NEF1High and NEF1Inst

Parameter Code Values Unit Default Data Explanation

direction
Operation mode S1 0 ... 2 1) - 1 R Selection of operation mode

Start current S2 0.10...12.00 x In 0.10 R Start current

Operate time S3 0.05...300.00 s 0.05 R Operate time in DT mode

1)
Operation mode 0 = Not in use; 1 = Definite time; 2 = Instantaneous

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 NEF1_ Substation Automation

3.2.2 Setting group 1

NEF1Low

Parameter Code Values Unit Default Data Explanation

direction
Operation mode S41 0 ... 15 1) - 1 R/W Selection of operation mode
and inverse-time
characteristic

Start current S42 1.0...100.0 % In 1.0 R/W Start current

Operate time S43 0.05...300.00 s 0.05 R/W Operate time in DT mode

Time multiplier S44 0.05...1.00 - 0.05 R/W Time multiplier ‘k’ in IDMT
mode

IEEE time dial S45 0.5...15.0 - 0.5 R/W IEEE time dial ‘n’ in IDMT
mode
1)
Operation mode 0 = Not in use; 1 = Definite time; 2 = Extremely inv.; 3 = Very inv.;
4 = Normal inv.; 5 = Long time inv.; 6 = RI-type inv.; 7 = RD-type inv.; 8 =
IEEE Ext.; 9 = IEEE Very inv.; 10 = IEEE Inverse; 11 = IEEE S.T. inv.; 12 =
IEEE S.T.E. inv; 13 = IEEE L.T.E. inv.; 14 = IEEE L.T.V. inv.; 15 = IEEE L.T.
inv.

NEF1High and NEF1Inst

Parameter Code Values Unit Default Data Explanation

direction
Operation mode S41 0 ... 2 1) - 1 R/W Selection of operation mode

Start current S42 0.10...12.00 x In 0.10 R/W Start current

Operate time S43 0.05...300.00 s 0.05 R/W Operate time in DT mode

1)
Operation mode 0 = Not in use; 1 = Definite time; 2 = Instantaneous

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 Substation Automation NEF1_

3.2.3 Setting group 2

NEF1Low

Parameter Code Values Unit Default Data Explanation

direction
Operation mode S71 0 ... 15 1) - 1 R/W Selection of operation mode
and inverse-time
characteristic

Start current S72 1.0...100.0 % In 1.0 R/W Start current

Operate time S73 0.05...300.00 s 0.05 R/W Operate time in DT mode

Time multiplier S74 0.05...1.00 - 0.05 R/W Time multiplier ‘k’ in IDMT
mode

IEEE time dial S75 0.5...15.0 - 0.5 R/W IEEE time dial ‘n’ in IDMT
mode
1)
Operation mode 0 = Not in use; 1 = Definite time; 2 = Extremely inv.; 3 = Very inv.;
4 = Normal inv.; 5 = Long time inv.; 6 = RI-type inv.; 7 = RD-type inv.; 8 =
IEEE Ext.; 9 = IEEE Very inv.; 10 = IEEE Inverse; 11 = IEEE S.T. inv.; 12 =
IEEE S.T.E. inv; 13 = IEEE L.T.E. inv.; 14 = IEEE L.T.V. inv.; 15 = IEEE L.T.
inv.

NEF1High and NEF1Inst

Parameter Code Values Unit Default Data Explanation

direction
Operation mode S71 0 ... 2 1) - 1 R/W Selection of operation mode

Start current S72 0.10...12.00 x In 0.10 R/W Start current

Operate time S73 0.05...300.00 s 0.05 R/W Operate time in DT mode

1)
Operation mode 0 = Not in use; 1 = Definite time; 2 = Instantaneous

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 NEF1_ Substation Automation

3.2.4 Control settings

NEF1Low

Parameter Code Values Unit Default Data Explanation

direction
Measuring mode V1 0 or 1 1) - 1 R/W Selection of measuring mode

Drop-off time V2 0...1000 ms 0 R/W Resetting time of the operate

time counter

Group selection V3 0 ... 2 2) - 0 R/W Selection of the active setting

group

Active group V4 0 or 1 3) - 0 R/M Active setting group

Start pulse V5 0...1000 ms 0 R/W Minimum pulse width of

START signal

Trip signal V6 0 or 1 4) - 0 R/W Selection of latching feature

for TRIP output

Trip pulse V7 40...1000 ms 40 R/W Minimum pulse width of TRIP

and CBFP

Minimum time V8 0.03...10.0 s 0.03 R/W Minimum operate time in

0 IDMT mode

CBFP time V9 100...1000 ms 100 R/W Operate time of the delayed

trip CBFP

Reset registers V13 1=Reset - - W Resetting of latched trip signal

and registers

Test START V31 0 or 1 5) - 0 R/W Testing of START

Test TRIP V32 0 or 1 5) - 0 R/W Testing of TRIP

5)
Test CBFP V33 0 or 1 - 0 R/W Testing of CBFP

Event mask 1 V101 0...4095 - 63 R/W Event mask 1 for event

transmission (E0 ... E11)

Event mask 2 V103 0...4095 - 63 R/W Event mask 2 for event

transmission (E0 ... E11)

Event mask 3 V105 0...4095 - 63 R/W Event mask 3 for event

transmission (E0 ... E11)

Event mask 4 V107 0...4095 - 63 R/W Event mask 4 for event

transmission (E0 ... E11)
1)
Measuring mode 0 = Peak-to-peak; 1 = Fundam.freq.
2)
Group selection 0 = Group 1; 1 = Group 2; 2 = GROUP input
3)
Active group 0 = Group 1; 1 = Group 2
4)
Trip signal 0 = Non-latching; 1 = Latching
5)
Test 0 = Do not activate; 1 = Activate

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Substation Automation NEF1_

NEF1High and NEF1Inst

Parameter Code Values Unit Default Data Explanation

direction
Measuring mode V1 0 or 1 1) - 1 R/W Selection of measuring mode

Drop-off time V2 0...1000 ms 0 R/W Resetting time of the operate

time counter

Group selection V3 0 ... 2 2) - 0 R/W Selection of the active setting

group

Active group V4 0 or 1 3) - 0 R/M Active setting group

Start pulse V5 0...1000 ms 0 R/W Minimum pulse width of

START signal

Trip signal V6 0 or 1 4) - 0 R/W Selection of latching feature

for TRIP output

Trip pulse V7 40...1000 ms 40 R/W Minimum pulse width of TRIP

and CBFP

CBFP time V8 100...1000 ms 100 R/W Operate time of the delayed

trip CBFP

Reset registers V13 1=Reset - 0 W Resetting of latched trip signal

and registers

Test START V31 0 or 1 5) - 0 R/W Testing of START

Test TRIP V32 0 or 1 5) - 0 R/W Testing of TRIP

5)
Test CBFP V33 0 or 1 - 0 R/W Testing of CBFP

Event mask 1 V101 0...4095 - 63 R/W Event mask 1 for event

transmission (E0 ... E11)

Event mask 2 V103 0...4095 - 63 R/W Event mask 2 for event

transmission (E0 ... E11)

Event mask 3 V105 0...4095 - 63 R/W Event mask 3 for event

transmission (E0 ... E11)

Event mask 4 V107 0...4095 - 63 R/W Event mask 4 for event

transmission (E0 ... E11)
1)
Measuring mode 0 = Peak-to-peak; 1 = Fundam.freq.
2)
Group selection 0 = Group 1; 1 = Group 2; 2 = GROUP input
3)
Active group 0 = Group 1; 1 = Group 2
4)
Trip signal 0 = Non-latching; 1 = Latching
5)
Test 0 = Do not activate; 1 = Activate

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 NEF1_ Substation Automation

3.3 Measurement values

3.3.1 Input data

NEF1Low

Parameter Code Values Unit Default Data Explanation

direction
Current Io I1 0.0...2000.0 % In 0.0 R/M Neutral current I0

Input BS1 I2 0 or 1 1) - 0 R/M Block signal BS1

1)
Input BS2 I3 0 or 1 - 0 R/M Block signal BS2

Input TRIGG I4 0 or 1 1) - 0 R/M Signal for triggering the registers

1)
Input GROUP I5 0 or 1 - 0 R/M Signal for switching between the
groups 1 and 2

Input BSREG I6 0 or 1 1) - 0 R/M Signal for blocking the recording

function

Input RESET I7 0 or 1 1) - 0 R/M Signal for resetting the output

signals and registers of
NEF1Low
1)
Input 0 = Not active; 1 = Active

NEF1High and NEF1Inst

Parameter Code Values Unit Default Data Explanation

direction
Current Io I1 0.00...60.00 x In 0.00 R/M Neutral current I0

Input BS1 I2 0 or 1 1) - 0 R/M Block signal BS1

1)
Input BS2 I3 0 or 1 - 0 R/M Block signal BS2

Input TRIGG I4 0 or 1 1) - 0 R/M Signal for triggering the registers

1)
Input GROUP I5 0 or 1 - 0 R/M Signal for switching between the
groups 1 and 2

Input BSREG I6 0 or 1 1) - 0 R/M Signal for blocking the recording

function

Input RESET I7 0 or 1 1) - 0 R/M Signal for resetting the output

signals and registers of
NEF1High or NEF1Inst
1)
Input 0 = Not active; 1 = Active

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 Substation Automation NEF1_

3.3.2 Output data

Parameter Code Values Unit Default Data Explanation

direction
Output START O1 0 or 1 1) - 0 R/M Status of start signal

Output TRIP O2 0 or 1 1) - 0 R/M Status of trip signal

1)
Output CBFP O3 0 or 1 - 0 R/M Status of CBFP signal
1)
Output 0 = Not active; 1 = Active

3.3.3 Recorded data

3.3.3.1 General

The information required for later fault analysis is recorded when the function block
starts or trips, or when the recording function is triggered via an external triggering
input.

The data of three last operations (operation 1...3) are recorded and the values of the
most recent operation always replace the data of the oldest operation. The registers
are updated in the following order: Operation 1, Operation 2, Operation 3, Operation
1, Operation 2,...

The recording function can be blocked via the BSREG input. For example, if an auto-
reclose sequence is initiated by the trip signal of the function block, the values most
reliable for later fault analysis are those recorded just before Shot 1. When the auto-
reclose sequence has started, no recordings are needed at the moment of tripping. The
output signal ACTIVE in AR5Func indicating AR in progress is connected to the
BSREG input to prevent useless recording.

3.3.3.2 Date and time

The time stamp indicates the rising edge of the START, TRIP or TRIGG signal.

3.3.3.3 Duration

In the DT mode of operation the duration of the start situation is recorded as a

percentage of the set operate time and, as concerns NEF1Low, in the IDMT mode of
operation as a percentage of the calculated operate time.

3.3.3.4 Neutral current

If the function block trips, the current values are updated at the moment of tripping
i.e. on the rising edge of the signal TRIP. For external triggering the current values are

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 NEF1_ Substation Automation

updated at the moment of triggering i.e. on the rising edge of the input signal TRIGG.
If the function block starts but does not trip, the neutral current value captured one
fundamental cycle (20 ms at rated frequency 50 Hz) after the beginning of the start
situation is recorded. The value of the neutral current I0 is recorded as a multiple of
the rated current In.

3.3.3.5 Status data

The status data of the input signals BS1 and BS2 as well as the “Active group”
parameter are recorded at the moment of recording. The “Active group” parameter
indicates the setting group valid for the recorded data.

3.3.3.6 Priority

The priority of the recording function is the following:

1 Tripping
2 Starting
3 External triggering,
which means that if the function block has started, it will neglect an external
triggering request.

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3.3.3.7 Recorded data 1

NEF1Low

Parameter Code Values Unit Default Data Explanation

direction
Date V201 YYYY-MM-DD - - R/M Recording date

Time V202 hh:mm:ss.mss - - R/M Recording time

Duration V203 0.0...100.0 % 0.0 R/M Duration of start situation

Io mean V204 0.0...2000.0 % In 0.0 R/M Filtered value of I0

Io peak V205 0.0...2000.0 % In 0.0 R/M Momentary peak of I0

BS1 V206 0 or 1 1) - 0 R/M Status of BS1 input

1)
BS2 V207 0 or 1 - 0 R/M Status of BS2 input

Active group V208 0 or 1 2) - 0 R/M Active setting group

1)
BS_ 0 = Not active; 1 = Active
2)
Active group 0 = Group 1; 1 = Group 2

NEF1High and NEF1Inst

Parameter Code Values Unit Default Data Explanation

direction
Date V201 YYYY-MM-DD - - R/M Recording date

Time V202 hh:mm:ss.mss - - R/M Recording time

Duration V203 0.0...100.0 % 0.0 R/M Duration of start situation

Io mean V204 0.00...60.00 x In 0.00 R/M Filtered value of I0

Io peak V205 0.00...60.00 x In 0.00 R/M Momentary peak of I0

1)
BS1 V206 0 or 1 - 0 R/M Status of BS1 input

BS2 V207 0 or 1 1) - 0 R/M Status of BS2 input

2)
Active group V208 0 or 1 - 0 R/M Active setting group
1)
BS_ 0 = Not active; 1 = Active
2)
Active group 0 = Group 1; 1 = Group 2

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 NEF1_ Substation Automation

3.3.3.8 Recorded data 2

NEF1Low

Parameter Code Values Unit Default Data Explanation

direction
Date V301 YYYY-MM-DD - - R/M Recording date

Time V302 hh:mm:ss.mss - - R/M Recording time

Duration V303 0.0...100.0 % 0.0 R/M Duration of start situation

Io mean V304 0.0...2000.0 % In 0.0 R/M Filtered value of I0

Io peak V305 0.0...2000.0 % In 0.0 R/M Momentary peak of I0

BS1 V306 0 or 1 1) - 0 R/M Status of BS1 input

1)
BS2 V307 0 or 1 - 0 R/M Status of BS2 input

Active group V308 0 or 1 2) - 0 R/M Active setting group

1)
BS_ 0 = Not active; 1 = Active
2)
Active group 0 = Group 1; 1 = Group 2

NEF1High and NEF1Inst

Parameter Code Values Unit Default Data Explanation

direction
Date V301 YYYY-MM-DD - - R/M Recording date

Time V302 hh:mm:ss.mss - - R/M Recording time

Duration V303 0.0...100.0 % 0.0 R/M Duration of start situation

Io mean V304 0.00...60.00 x In 0.00 R/M Filtered value of I0

Io peak V305 0.00...60.00 x In 0.00 R/M Momentary peak of I0

BS1 V306 0 or 1 1) - 0 R/M Status of BS1 input

1)
BS2 V307 0 or 1 - 0 R/M Status of BS2 input

Active group V308 0 or 1 2) - 0 R/M Active setting group

1)
BS_ 0 = Not active; 1 = Active
2)
Active group 0 = Group 1; 1 = Group 2

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3.3.3.9 Recorded data 3

NEF1Low

Parameter Code Values Unit Default Data Explanation

direction
Date V401 YYYY-MM-DD - - R/M Recording date

Time V402 hh:mm:ss.mss - - R/M Recording time

Duration V403 0.0...100.0 % 0.0 R/M Duration of start situation

Io mean V404 0.0...2000.0 % In 0.0 R/M Filtered value of I0

Io peak V405 0.0...2000.0 % In 0.0 R/M Momentary peak of I0

BS1 V406 0 or 1 1) - 0 R/M Status of BS1 input

1)
BS2 V407 0 or 1 - 0 R/M Status of BS2 input

Active group V408 0 or 1 2) - 0 R/M Active setting group

1)
BS_ 0 = Not active; 1 = Active
2)
Active group 0 = Group 1; 1 = Group 2

NEF1High and NEF1Inst

Parameter Code Values Unit Default Data Explanation

direction
Date V401 YYYY-MM-DD - - R/M Recording date

Time V402 hh:mm:ss.mss - - R/M Recording time

Duration V403 0.0...100.0 % 0.0 R/M Duration of start situation

Io mean V404 0.00...60.00 x In 0.00 R/M Filtered value of I0

Io peak V405 0.00...60.00 x In 0.00 R/M Momentary peak of I0

BS1 V406 0 or 1 1) - 0 R/M Status of BS1 input

1)
BS2 V407 0 or 1 - 0 R/M Status of BS2 input

Active group V408 0 or 1 2) - 0 R/M Active setting group

1)
BS_ 0 = Not active; 1 = Active
2)
Active group 0 = Group 1; 1 = Group 2

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 NEF1_ Substation Automation

3.3.4 Events

Code Weighting Default Event reason Event state

coefficient mask
E0 1 1 START signal from Io>, Io>> or Io>>> stage Reset

E1 2 1 START signal from Io>, Io>> or Io>>> stage Activated

E2 4 1 TRIP signal from Io>, Io>> or Io>>> stage Reset

E3 8 1 TRIP signal from Io>, Io>> or Io>>> stage Activated

E4 16 1 CBFP signal from Io>, Io>> or Io>>> stage Reset

E5 32 1 CBFP signal from Io>, Io>> or Io>>> stage Activated

E6 64 0 BS1 signal of Io>, Io>> or Io>>> stage Reset

E7 128 0 BS1 signal of Io>, Io>> or Io>>> stage Activated

E8 256 0 BS2 signal of Io>, Io>> or Io>>> stage Reset

E9 512 0 BS2 signal of Io>, Io>> or Io>>> stage Activated

E10 1024 0 Test mode of Io>, Io>> or Io>>> stage Off

E11 2048 0 Test mode of Io>, Io>> or Io>>> stage On

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Substation Automation NEF1_

4. Technical data

Operation accuracies Depends on the frequency of the current measured:

NEF1Low:

f/fn= 0.95...1.05: ±2.5% of set value + 0.0005 x In.

NEF1High and NEF1Inst:

f/fn= 0.95...1.05: ±2.5% of set value or +0.01 x In.

Start time Injected currents > 2.0 x start current:

f/fn = 0.95...1.05 internal time < 32 ms

1)
total time < 40 ms

Reset time 40...1000 ms (depends on the set minimum output pulse width)

Reset ratio Typ. 0.95 (range 0.95...0.98)

Retardation time Total retardation time when the current drops

below the start value2) < 45 ms

Operate time accuracy Depends on the frequency of the current measured:

in definite-time mode
f/fn = 0.95...1.05: ± 2% of set value or ± 20 ms2)

Accuracy class index E Depends on the frequency of the current measured:

in inverse-time mode
(NEF1Low) f/fn = 0.95...1.05: Class index E = 5.0 or ±20 ms2)

Suppression of harmonics Measuring mode

0 No suppression

1 -50 dB at f = n x fn, where n = 2, 3, 4, 5,...

Configuration data Task execution interval (Relay Configuration Tool): 10 ms,

at the rated frequency fn = 50 Hz
1)
Includes the delay of the signal relay
2)
Includes the delay of the heavy-duty output relay

Technical revision history

Function block Technical Change
revision
NEF1Low B -

C -

D - added IEEE IDMT curves

NEF1High B -

C -

NEF1Inst B -

C - (No change in the manual)

D -

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