Arcteq AQ T3 Series User manual

INSTRUCTION MANUAL
AQ T3xx
Transformer Protection IED

Instruction manual –AQ T3xx Transformer Protection IED 2 (165)
Revision
1.00
Date
November 2010
Changes
-The first revision.
Revision
1.01
Date
January 2011
Changes
-HW construction and application drawings revised
Revision
1.02
Date
February 2011
Changes
-AVR chapter added
-Synchrocheck chapter revised
-Voltage measurement module revised
-CPU module description added
-Binary input module description revised
-IRIG-B information added
-Updated ordering information and type designation
-Technical data revised
Revision
1.03
Date
July 2012
Changes
-Added 2nd REF stage
-Added Volts-per-Hertz protection
-Frequency specifications updated
Revision
1.04
Date
17.1.2014
Changes
-Added mA input module (option).
-Added setting example to the end of differential function
description.
Revision
1.05
Date
11.2.2015
Changes
-Current and voltage measurement descriptions revised
Revision
1.06
Date
25.3.2015
Changes
-Trip logic description revised
-Differential protection parameters revised
-Added Connection examples-chapter to measurements
-Added Line measurements-description
-Added Common-function-description
Revision
1.07
Date
17.12.2019
Changes
-Updated construction and installation chapter

Instruction manual –AQ T3xx Transformer Protection IED 3 (165)
Read these instructions carefully and inspect the equipment to become familiar with it
before trying to install, operate, service or maintain it.
Electrical equipment should be installed, operated, serviced, and maintained only by
qualified personnel. Local safety regulations should be followed. No responsibility is
assumed by Arcteq for any consequences arising out of the use of this material.
We reserve right to changes without further notice.

Instruction manual –AQ T3xx Transformer Protection IED 4 (165)
TABLE OF CONTENTS
1ABBREVIATIONS ............................................................................................................. 7
2GENERAL......................................................................................................................... 8
3SOFTWARE SETUP OF THE IED .................................................................................... 9
3.1 Measurements ..................................................................................................... 10
3.1.1 Current measurement and scaling .............................................................. 10
3.1.2 Voltage measurement and scaling .............................................................. 13
3.1.3 Connection example ................................................................................... 18
3.1.4 Line measurement ...................................................................................... 21
3.2 Protection Functions ............................................................................................ 28
3.2.1 Transformer differential 3Id> (87T) .............................................................. 28
3.2.2 Restricted earth fault REF (87N)................................................................. 40
3.2.3 Three-phase instantaneous overcurrent I>>> (50) ...................................... 44
3.2.4 Residual instantaneous overcurrent I0>>> (50N)........................................ 47
3.2.5 Three-phase time overcurrent I>, I>> (50/51).............................................. 48
3.2.6 Residual time overcurrent I0>, I0>> (51N) .................................................. 64
3.2.7 Current unbalance (60) ............................................................................... 66
3.2.8 Thermal overload T>, (49L) ........................................................................ 68
3.2.9 Over voltage U>, U>> (59).......................................................................... 70
3.2.10 Under voltage U<, U<< (27)........................................................................ 71
3.2.11 Residual over voltage U0>, U0>> (59N) ..................................................... 73
3.2.12 Over frequency f>, f>>, (81O) ..................................................................... 74
3.2.13 Under frequency f<, f<<, (81U) ................................................................... 75
3.2.14 Rate of change of frequency df/dt>, df/dt>> (81R) ...................................... 76
3.2.15 Over excitation V/Hz (24)............................................................................ 77
3.2.16 Breaker failure protection function CBFP, (50BF) ....................................... 85
3.2.17 Inrush current detection (INR2), (68)........................................................... 88
3.3 Control and monitoring functions.......................................................................... 88
3.3.1 Common-function ....................................................................................... 88
3.3.2 Trip logic (94).............................................................................................. 91
3.3.3 Voltage transformer supervision VTS (60) .................................................. 94
3.3.4 Current transformer supervision (CTS) ....................................................... 97
3.3.5 Synchrocheck du/df (25) ............................................................................. 99
3.3.6 Integrated automatic voltage regulator (AVR) ........................................... 108

Instruction manual –AQ T3xx Transformer Protection IED 5 (165)
3.3.7 Switch on to fault logic .............................................................................. 120
3.3.8 Disturbance recorder ................................................................................ 123
3.3.9 Event recorder .......................................................................................... 124
3.3.10 Measured values ...................................................................................... 128
3.3.11 Status monitoring the switching devices.................................................... 129
3.3.12 Trip circuit supervision .............................................................................. 130
3.3.13 LED assignment ....................................................................................... 130
4SYSTEM INTEGRATION .............................................................................................. 131
5CONNECTIONS............................................................................................................ 132
5.1 Block diagram AQ-T352 minimum options ........................................................ 132
5.2 Block diagram AQ-T352 all options................................................................... 133
5.3 Connection example of AQ-T352 ....................................................................... 134
5.4 Block diagram AQ-T392 minimum options ......................................................... 135
5.5 Block diagram AQ-T392 all options.................................................................... 136
5.6 Block diagram AQ-T393 minimum options ........................................................ 137
5.7 Block diagram AQ-T393 all options................................................................... 138
5.8 Connection example of AQ-T393 ....................................................................... 139
6CONSTRUCTION AND INSTALLATION....................................................................... 140
6.1 Construction and installation of AQ-T352........................................................... 140
6.2 Construction and installation of AQ-T392........................................................... 141
6.3 Construction and installation of AQ-T393........................................................... 142
6.4 CPU module ...................................................................................................... 143
6.5 Power supply module......................................................................................... 144
6.6 Binary input module ........................................................................................... 145
6.7 Binary output modules for signaling ................................................................... 146
6.8 Tripping module ................................................................................................. 147
6.9 Voltage measurement module ........................................................................... 148
6.10 Current measurement module............................................................................ 149
6.11 mA input module................................................................................................ 150
6.12 Installation and dimensions................................................................................ 151
7TECHNICAL DATA ....................................................................................................... 155
7.1 Protection functions ........................................................................................... 155
7.1.1 Differential protection functions................................................................. 155
7.1.2 Overcurrent protection functions ............................................................... 155
7.1.3 Voltage protection functions...................................................................... 157

Instruction manual –AQ T3xx Transformer Protection IED 6 (165)
7.1.4 Frequency protection functions ................................................................. 157
7.1.5 Other protection functions......................................................................... 158
7.2 Control functions................................................................................................ 159
7.3 Hardware ........................................................................................................... 160
7.3.1 Power supply module................................................................................ 160
7.3.2 Current measurement module .................................................................. 160
7.3.3 Voltage measurement module .................................................................. 161
7.3.4 High speed trip module ............................................................................. 161
7.3.5 Binary output module................................................................................ 161
7.3.6 Binary input module .................................................................................. 161
7.3.7 mA input module....................................................................................... 161
7.4 Tests and environmental conditions................................................................... 162
7.4.1 Disturbance tests ...................................................................................... 162
7.4.2 Voltage tests............................................................................................. 162
7.4.3 Mechanical tests ....................................................................................... 162
7.4.4 Casing and package ................................................................................. 162
7.4.5 Environmental conditions.......................................................................... 163
8ORDERING INFORMATION ......................................................................................... 164
9REFERENCE INFORMATION ...................................................................................... 165

Instruction manual –AQ T3xx Transformer Protection IED 7 (165)
1ABBREVIATIONS
CB –Circuit breaker
CBFP –Circuit breaker failure protection
CT –Current transformer
CPU –Central processing unit
EMC –Electromagnetic compatibility
HMI –Human machine interface
HW –Hardware
IED –Intelligent electronic device
IO –Input output
LED –Light emitting diode
LV –Low voltage
MV –Medium voltage
NC –Normally closed
NO –Normally open
RMS –Root mean square
SF –System failure
TMS –Time multiplier setting
TRMS –True root mean square
VAC –Voltage alternating current
VDC –Voltage direct current
SW –Software
uP - Microprocessor

Instruction manual –AQ T3xx Transformer Protection IED 8 (165)
2GENERAL
The AQ-T3xx transformer protection IEDs are members of the AQ-300 product line. The
AQ-300 protection product line in respect of hardware and software is a modular device.
The hardware modules are assembled and configured according to the application IO
requirements and the software determines the available functions. This manual describes
the specific application of the AQ-T3xx transformer protection IEDs.
Arcteq protection IED can be ordered in two mechanical sizes. The AQ-T35x comes in half
of 19 inch rack arrangement and the AQ-T39x comes in full 19 inch rack arrangement
allowing for larger quantity of IO cards. The functionality is the same in both units.

Instruction manual –AQ T3xx Transformer Protection IED 9 (165)
3SOFTWARE SETUP OF THE IED
In this chapter are presented the protection and control functions as well as the monitoring
functions.
The implemented protection functions are listed in Table 3-1. The function blocks are
described in details in following chapters.
Table 3-1 Available protection functions
Function Name
IEC
ANSI
Description
DIF87
3IdT>
87T
Transformer differential protection
DIF87N
REF
87N
Restricted earth fault protection (low impedance)
IOC50
I >>>
50
Three-phase instantaneous overcurrent protection
TOC50_low
TOC50_high
I>
I>>
51
Three-phase time overcurrent protection
IOC50N
I0 >>>
50N
Residual instantaneous overcurrent protection
TOC51N_low
TOC51N_high
I0>
I0>>
51N
Residual time overcurrent protection
INR2
I2h >
68
Inrush detection and blocking
VCB60
Iub >
60
Current unbalance protection
TTR49L
T >
49T
Line thermal protection
TOV59_low
TOV59_high
U >
U >>
59
Definite time overvoltage protection
TUV27_low
TUV27_high
U <
U <<
27
Definite time undervoltage protection
TOV59N_low
TOV59N_high
U0>
U0>>
59N
Residual voltage protection
TOF81_high
TOF81_low
f >
f >>
81O
Overfrequency protection
TUF81_high
TUF81_low
f <
f <<
81U
Underfrequency protection
FRC81_high
FRC81_low
df/dt
81R
Rate of change of frequency protection
VPH24
V/Hz
24
Overexcitation protection (V/Hz)
BRF50MV
CBFP
50BF
Breaker failure protection

Instruction manual –AQ T3xx Transformer Protection IED 10 (165)
Table 3-2 Available control and monitoring functions
Name
IEC
ANSI
Description
TRC94
-
94
Trip logic
VTS
-
60
Voltage transformer supervision
SYN25
SYNC
25
Synchro-check function Δf, ΔU, Δφ
AVR
-
-
Integrated voltage regulator (option)
DREC
-
-
Disturbance recorder
3.1 MEASUREMENTS
3.1.1 CURRENT MEASUREMENT AND SCALING
If the factory configuration includes a current transformer hardware module, the current
input function block is automatically configured among the software function blocks.
Separate current input function blocks are assigned to each current transformer hardware
module.
A current transformer hardware module is equipped with four special intermediate current
transformers. As usual, the first three current inputs receive the three phase currents (IL1,
IL2, IL3), the fourth input is reserved for zero sequence current, for the zero sequence
current of the parallel line or for any additional current. Accordingly, the first three inputs
have common parameters while the fourth current input needs individual setting.
The role of the current input function block is to
•set the required parameters associated to the current inputs,
•deliver the sampled current values for disturbance recording,
•perform the basic calculations
oFourier basic harmonic magnitude and angle,
oTrue RMS value;
•provide the pre-calculated current values to the subsequent software function
blocks,
•deliver the calculated Fourier basic component values for on-line displaying.
The current input function block receives the sampled current values from the internal
operating system. The scaling (even hardware scaling) depends on parameter setting, see
parameters Rated Secondary I1-3 and Rated Secondary I4. The options to choose from are
1A or 5A (in special applications, 0.2A or 1A). This parameter influences the internal number

Instruction manual –AQ T3xx Transformer Protection IED 11 (165)
format and, naturally, accuracy. A small current is processed with finer resolution if 1A is
selected.
If needed, the phase currents can be inverted by setting the parameter Starpoint I1-3. This
selection applies to each of the channels IL1, IL2 and IL3. The fourth current channel can
be inverted by setting the parameter Direction I4. This inversion may be needed in
protection functions such as distance protection, differential protection or for any functions
with directional decision.
Figure 3-1 Example connection
Phase current CT:
CT primary 100A
CT secondary 5A
Ring core CT in Input I0:
I0CT primary 10A
I0CT secondary 1A
Phase current CT secondary currents starpoint is towards the line.
Figure 3-2 Example connection with phase currents connected into summing “Holmgren”
connection into the I0 residual input.
Phase current CT:
CT primary 100A
Ring core CT in Input I0:
I0CT primary 100A

Instruction manual –AQ T3xx Transformer Protection IED 12 (165)
CT secondary 5A
I0CT secondary 5A
Phase currents are connected to summing “Holmgren” connection into the I0
residual input.
The sampled values are available for further processing and for disturbance recording.
The performed basic calculation results the Fourier basic harmonic magnitude and angle
and the true RMS value. These results are processed by subsequent protection function
blocks and they are available for on-line displaying as well.
The function block also provides parameters for setting the primary rated currents of the
main current transformer (Rated Primary I1-3 and Rated Primary I4). This function block
does not need that parameter settings. These values are passed on to function blocks such
as displaying primary measured values, primary power calculation, etc.
Table 3-3 Enumerated parameters of the current input function
Table 3-4 Floating point parameters of the current input function

Instruction manual –AQ T3xx Transformer Protection IED 13 (165)
Table 3-5 Online measurements of the current input function
NOTE1: The scaling of the Fourier basic component is such that if pure sinusoid 1A RMS
of the rated frequency is injected, the displayed value is 1A. The displayed value does not
depend on the parameter setting values “Rated Secondary”.
NOTE2: The reference of the vector position depends on the device configuration. If a
voltage input module is included, then the reference vector (vector with angle 0 degree) is
the vector calculated for the first voltage input channel of the first applied voltage input
module. If no voltage input module is configured, then the reference vector (vector with
angle 0 degree) is the vector calculated for the first current input channel of the first applied
current input module. (The first input module is the one, configured closer to the CPU
module.)
3.1.2 VOLTAGE MEASUREMENT AND SCALING
If the factory configuration includes a voltage transformer hardware module, the voltage
input function block is automatically configured among the software function blocks.
Separate voltage input function blocks are assigned to each voltage transformer hardware
module.
A voltage transformer hardware module is equipped with four special intermediate voltage
transformers. As usual, the first three voltage inputs receive the three phase voltages (UL1,
UL2, UL3), the fourth input is reserved for zero sequence voltage or for a voltage from the
other side of the circuit breaker for synchro switching.
The role of the voltage input function block is to
•set the required parameters associated to the voltage inputs,
•deliver the sampled voltage values for disturbance recording,
•perform the basic calculations
oFourier basic harmonic magnitude and angle,

Instruction manual –AQ T3xx Transformer Protection IED 14 (165)
oTrue RMS value;
•provide the pre-calculated voltage values to the subsequent software modules,
•deliver the calculated basic Fourier component values for on-line displaying.
The voltage input function block receives the sampled voltage values from the internal
operating system. The scaling (even hardware scaling) depends on a common parameter
“Range” for type selection. The options to choose from are 100V or 200V, no hardware
modification is needed. A small voltage is processed with finer resolution if 100V is selected.
This parameter influences the internal number format and, naturally, accuracy.
There is a correction factor available if the rated secondary voltage of the main voltage
transformer (e.g. 110V) does not match the rated input of the device. The related parameter
is “VT correction“. As an example: if the rated secondary voltage of the main voltage
transformer is 110V, then select Type 100 for the parameter “Range” and the required value
to set here is 110%.
The connection of the first three VT secondary windings must be set to reflect actual
physical connection of the main VTs. The associated parameter is “Connection U1-3“. The
selection can be: Ph-N, Ph-Ph or Ph-N-Isolated.
The Ph-N option is applied in solidly grounded networks, where the measured phase
voltage is never above 1.5-Un. In this case the primary rated voltage of the VT must be the
value of the rated PHASE-TO-NEUTRAL voltage.
Figure 3-3 Phase to neutral connection. Connection U1-3

Instruction manual –AQ T3xx Transformer Protection IED 15 (165)
Ph-N Voltage:
Rated Primary U1-3: 11.55kV (=20kv/√3)
Range: Type 100
Residual voltage:
Rated Primary U4: 11.54A
If phase-to-phase voltage is connected to the VT input of the device, then the Ph-Ph option
is to be selected. Here, the primary rated voltage of the VT must be the value of the rated
PHASE-TO-PHASE voltage. This option must not be selected if the distance protection
function is supplied from the VT input.
Figure 3-4 Phase-to-phase connection.
Ph-N Voltage:
Rated Primary U1-3: 20kV
Range: Type 100
Residual voltage:
Rated Primary U4: 11.54kV
(=20kv/√3)
The fourth input is reserved for zero sequence voltage or for a voltage from the other side
of the circuit breaker for synchron switching. Accordingly, the connected voltage must be
identified with parameter setting “Connection U4“. Here, phase-to-neutral or phase-to-
phase voltage can be selected: Ph-N, Ph-Ph.
If needed, the phase voltages can be inverted by setting the parameter “Direction U1-3“.
This selection applies to each of the channels UL1, UL2 and UL3. The fourth voltage
channel can be inverted by setting the parameter “Direction U4“. This inversion may be
needed in protection functions such as distance protection or for any functions with
directional decision, or for checking the voltage vector positions.

Instruction manual –AQ T3xx Transformer Protection IED 16 (165)
These modified sampled values are available for further processing and for disturbance
recording.
The function block also provides parameters for setting the primary rated voltages of the
main voltage transformers. This function block does not need that parameter setting but
these values are passed on to function blocks such as displaying primary measured values,
primary power calculation, etc.
Table 3-6 Enumerated parameters of the voltage input function
Table 3-7 Integer parameters of the voltage input function
Table 3-8 Float point parameters of the voltage input function
NOTE: The rated primary voltage of the channels is not needed for the voltage input function
block itself. These values are passed on to the subsequent function blocks.

Instruction manual –AQ T3xx Transformer Protection IED 17 (165)
Table 3-9 On-line measured analogue values of the voltage input function
NOTE1: The scaling of the Fourier basic component is such if pure sinusoid 57V RMS of
the rated frequency is injected, the displayed value is 57V. The displayed value does not
depend on the parameter setting values “Rated Secondary”.
NOTE2: The reference vector (vector with angle 0 degree) is the vector calculated for the
first voltage input channel of the first applied voltage input module. The first voltage input
module is the one, configured closer to the CPU module.

Instruction manual –AQ T3xx Transformer Protection IED 18 (165)
3.1.3 CONNECTION EXAMPLE
Figure 3-5 Connection example with current breaker open and close connection, CT and
VT connection.

Instruction manual –AQ T3xx Transformer Protection IED 19 (165)
Figure 3-6 Example connection with two CT:s facing each other. Starpoint directions are
both set to “Line”.

Instruction manual –AQ T3xx Transformer Protection IED 20 (165)
Figure 3-7 Connection example where the direction of the secondary sides starpoint
direction has been inverted. Notice the inverted parameter Starpoint I1-3: “Bus”.