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Application description 10/2016
Determining the reactive
power through the Active
Line Module
Warranty and liability
Application description ALM
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Warranty and liability
Note
We do not accept any liability for the information contained in this document.
Any claims against us – based on whatever legal reason – resulting from the use of
the examples, information, programs, engineering and performance data etc.,
described in this Application Example shall be excluded. Such an exclusion shall
not apply in the case of mandatory liability, e.g. under the German Product Liability
Act (“Produkthaftungsgesetz”), in case of intent, gross negligence, or injury of life,
body or health, guarantee for the quality of a product, fraudulent concealment of a
deficiency or breach of a condition which goes to the root of the contract
(“wesentliche Vertragspflichten”). The damages for a breach of a substantial
contractual obligation are, however, limited to the foreseeable damage, typical for
the type of contract, except in the event of intent or gross negligence or injury to
life, body or health. The above provisions do not imply a change of the burden of
proof to your detriment.
Any form of duplication or distribution of these Application Examples or excerpts
hereof is prohibited without the expressed consent of the Siemens AG.
Security
informa-
tion
Table of contents
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Table of contents
Warranty and liability ................................................................................................... 2
1 Application description ..................................................................................... 4
1.1 Overview............................................................................................... 4
1.2 Advantages .......................................................................................... 5
1.3 Requirement’s / Scenario ..................................................................... 5
2 Basics ................................................................................................................. 6
2.1 Voltage load: ........................................................................................ 6
2.2 Load duty cycles: .................................................................................. 7
2.3 Conductor cross-sections: .................................................................... 7
2.4 Transformer .......................................................................................... 7
2.5 Characteristic line ................................................................................. 9
3 Solution............................................................................................................. 12
3.1 Functionality ....................................................................................... 12
3.2 Determining reactive power................................................................ 12
3.2.1 Reactive power compensation on the secondary side of the
transformer ......................................................................................... 12
3.2.2 Reactive power compensation on the primary side of the
transformer ......................................................................................... 13
3.3 Hard- and software components ........................................................ 20
3.3.1 SINAMICS HW components .............................................................. 20
3.3.2 SW- components ................................................................................ 21
4 Contact.............................................................................................................. 22
1 Application description
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1 Application description
1.1 Overview
Introduction
In applications involving drive converters, generally motors are not operated at a
constant speed. As a consequence, in most cases the infeed unit operates in
partial load range. If the infeed involves an Active Line Module (ALM), which is
installed in a SINAMICS S150 or for SINAMICS S120 Cabinet Modules or for
SINAMICS S120, then there is now the option of utilizing the reserve of ALM to
compensate line supply. This document describes how to determine how much
reactive power the Active Line Module can make available for the line supply.
Overview about the Application
Following picture shows the structure of Application.
Image 1-1
common line
connection
reactive power loads
drive line-up consisting
of an Active Interface
Module, Active Line
Module, Motor Module
and motor
CU320-2
Voltage
Sensing Module
VSM10
DRIVE-CLiQ
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1.2 Advantages
Following are the advantages of Active Line Module for reactive power compensation:
If the reactive power is adequate, then an additional reactive power
compensation system is not required
The transformer only transfers the required active power
Lower transformer losses (increasing cos has the following effect on the
losses 
󰇛󰇜)
Lower voltage drop across the transformer
For this particular application, you require a DCC Plan and additional components
to measure the current and voltage. You can find this information in the application
description "SINAMICS S120 reactive power compensation with Active Line
Module and DCC" under the following link:
http://support.automation.siemens.com/WW/view/en/57886317
1.3 Requirement’s / Scenario
Additional reactive power will be generated through the grid if the industry plants
operate in different loads at the transformer. In the most cases the customers are
anxious to compensate the reactive power and use the customer girds with a
continuous power factor (cosφ).
The infeed concept allows a reactive power feed through the Active Line Module.
In the industrial applications these component can also support an additional
contribution in the reactive power if the ALM takes over the drive tasks. The ALM is
qualified to compensate the fundamental reactive power, but this is only limited
for symmetrical loads.
The compensation of the harmonics and the unsymmetrical reactive power is not
possible.
2 Basics
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2 Basics
2.1 Voltage load:
If the reactive-power compensation is carried out at the same voltage level, then
the voltage will increase up to the maximal no-load voltage.
In the case the reactive-power compensation is carried out at the overlapped
voltage level (primary side), then the reactive power is transferred over the
transformer. If the ALM will use with lower excited operation, then it takes to an
inductive reactive power and behaves like an inductor at the grid. In this case the
voltage will be reduced on the secondary side of the transformer. If the ALM is
used in the over excited operation, then it takes a capacitive reactive power and
behaves like a condenser at the grid. In this case the voltage increased on the
secondary side of the transformer.
Furthermore the following points have to be taken into account, if reactive power
over the transformer is transferred:
The SINAMICS converter can be operated both with 10% over voltage and with
10% under voltage. This also includes the components like fans which are in the
converter. As well all options which can be ordered to the standard device.
These components are provided about auxiliary transformer. This transformer
provides 230 V on the output side. If the voltage gets higher than the 110% or
smaller than the 90%, then a USV should be used.
Moreover even further equipment is operated at the transformer besides the
converter; it must be sure, that also other equipment has to be set for higher or
lower voltage.
By ordering the transformer, it should be noted that this can be operated up to
100% with inductive or capacitive load. Especially at capacitive load, the flux rises
in the leg of the transformer. This load hast to be considered by configuring the
transformer otherwise it can lead to overheating.
Primarily the capacitive load can affect in certain cases the grid perturbation,
because the ALM keeps control factor less than 97% (into factory default). The
control factor is the rate between the grid and intermediate circuit voltage. If the
grid voltage rises further by supply of a capacitive reactive power, then the control
factor 97% is exceeded. On the other hand, the ALM regulates and increases the
intermediate circuit voltage so that the control factor gets down to the 97% again.
This happens as long as till the value in the parameter p0280 is reached (maximum
intermediate circuit voltage). The grid perturbation increases due to the exceeding
of the control factor.
In addition the ALM will be extended by using a Motor Module with mtor and is not
only used by regulating the reactive power, then some specification must be taken
into account. The voltage stress at the motor isolation increases due to the higher
intermediate circuit voltage. This should be considered by choosing the right
isolation system for the motor. Likewise must be considered the maximum
intermediate circuit voltage, when on output side of the motor a du/dt filter is
placed.
400 V device Udcmax 720V (continuous operation)
690 V device Udcmax 1080V (continuous operation)
During the dimensioning of the ALM has to be respected that the device supplies
enough power for the case without capacitive reactive power or maximum inductive
reactive power.
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2.2 Load duty cycles:
If the loads connected to the line supply require high levels of reactive powers
periodically, then the power cycling capability derating (derating factor kIGBT‘) must
be taken into account the same as for the corresponding Motor Modules. However,
this is only required if the load duty cycle deviates from the standard duty cycle, i.e.
if the value Δ I is greater than 1.5 and/or the load duty cycle is shorter than 300s.
You can find more detailed information in the SINAMICS Low-Voltage in the "Load
duty cycles" section.
2.3 Conductor cross-sections:
For the cabinet units SINAMICS S150, fuses and cable cross sections are
recommended in the documentation. These recommendations are selected based
on the type and ratings of the motors to be connected, and the line currents that
are obtained, under the assumption that the ALM only draws pure active power
and therefore pure active current, as is the case for the factory setting. As a
consequence, these values are not identical with the currents of the chassis format
ALMs used in the S150. If the reactive current is determined from the rated
currents of the Active Line Modules and the required active current of the Motor
Modules, then the required cable cross-sections must be carefully observed. This
is especially important for lower power ratings. Another important issue here is that
the ALM is not the limiting component, but the fuse, which is recommended. As a
consequence, after determining the reactive power that is available, the absolute
current should also be determined to ensure that the recommended fuse is not
overloaded. The ALMs used in the converter cabinet units together with their line-
side rated currents are listed in the following table.
2.4 Transformer
The equivalent circuit of the transformer consists of a lengthways and shunt arm.
The resistances and the leakage inductances are placed in the shunt arm. The
main inductance is in the shunt arm and is caused by the main flow in the
transformer. Also a resistance is in the shunt arm, this simulates the eddy current
losses and the magnetic reversal losses.
Depending on the way of the load the voltage is raised or let down on the
secondary side. It can be recognized that the voltage drop is the lowest by purely
ohmic load. On the other hand the transformer is loaded with inductance the
voltage drop is the strongest. On the secondary side increased the voltage if the
transformer is loaded with capacity load.
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For configuration of the ALM it is important to determine the voltage, therewith the
current can be determined for the required apparent power. The triangle gives the
opportunity to calculate the voltage, which is depending of the apparent power and
its angel on the secondary side of the transformer.
For the calculation of the inductive power which remains in the transformer it is
possible to further simplify the equivalent circuit of the transformer. On the next
page, the two stray inductances and the resistances can be summarized. The
resistances and stray inductances refer to the either primary or secondary side.
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2.5 Characteristic line
The Active Line Module is operated with a basic fundamental power factor of cos
<1, then the losses in the Active Line Module increases as a result of the
modulation system employed. This is the reason that the permissible input current
of the Active Line Module, referred to the rated current IN, must be reduced. The
values can be taken from the following derating characteristic. The first two
characteristics are valid for Chassis format devices – as well as for cabinet units;
the last two characteristics are valid for booksize format devices.
Permissible line current of the SINAMICS Active Infeed as a function of the line-side power factor
cosφ
Zulässiger
Netzstrom
1,00
0,95
0,90
0,85
0,80
0,75
0,00 cosφ
1,00 0,80 0,60 0,40 0,20 0,00
Derating characteristic for ALM chassis format for ALM booksize format with 120kW
Permitted
grid voltage
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From the derating characteristics for chassis and booksize ALMs, a characteristic
was derived. This can be used to determine the minimum possible basic
fundamental power factor cos based on the ratio of active current and rated input
current of the ALM. Using the cos, it is now possible to determine the reactive
power that can be provided for the line supply. At the end of the document, the
procedure is shown based on an example.
Characteristic for ALM chassis format for ALM booksize format with 120kW
Derating characteristic for Booksize ALMs up to 80kW
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0,50
0,55
0,60
0,65
0,70
0,75
0,80
0,85
0,90
0,95
1,00
0,00
0,04
0,08
0,11
0,15
0,19
0,23
0,27
0,32
0,36
0,41
0,45
0,50
0,56
0,61
0,67
0,73
0,79
0,86
0,93
1,00
cos φ
Iw/
IN
Chassis Chassis
Permitted
grid voltage
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This characteristic is only valid for Booksize ALMs with a power rating of up to 80kW
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0,50
0,55
0,60
0,65
0,70
0,75
0,80
0,85
0,90
0,95
1,00
0,00
0,05
0,09
0,14
0,18
0,23
0,28
0,33
0,38
0,43
0,48
0,53
0,58
0,63
0,68
0,73
0,78
0,84
0,89
0,95
1,00
cos φ
Iw/
IN
Booksize Booksize
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3 Solution
3.1 Functionality
With Active Line Module can be rated the current in his active current component lg
and reactive current component ld.
According to the factory setting only the active current is regulated and no external
setpoint is specified for the reactive current. As a consequence, the Active Line
Module only provides as much reactive power as the Clean Power filter in the
associated Active Interface Module required. In this way, the Active Infeed or the
converter only draws active power from the line supply.
With the SINAMICS DCC the possibility exists to determine a reactive current rated
value as a function of the power factor from the grid data and to provide this as a
reactive current rated value of the ALM regulation.
Using the DCC chart, a supplementary setpoint channel is interconnected, so that
the converter now supplies additional reactive power back into the line supply. On
the line side this results in a basic fundamental power factor of cos<1.
3.2 Determining reactive power
3.2.1 Reactive power compensation on the secondary side of the
transformer
Example to determine the reactive power
A SIMOTICS N-compact 1LA8407-4PM70 induction motor is to be controlled from
a SINAMICS S150 / 710kW / 690V. In this example, it is assumed that the line
supply has no significant voltage dips. Otherwise, this would have to be taken into
account when determining active current IW.
For this particular application, the operating point with the highest power is at 1300
rpm and a power of 600kW. The motor has an efficiency of 96.4%, the SINAMICS
S150 has a power loss of 30.25kW (see catalog). The Motor Module only transfers
active power to the Active Line Module via the DC link. As a consequence, the first
step is to determine just how much power the motor draws. You determine the
power loss of the SINAMICS S150 from the catalog.
 

 
     
Determining the active current IW:
 
 

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SINAMICS S150 with 710kW has a rated current of IN= 735A.

 
 
From the characteristic, for IW/IN=0.74, we obtain a cos of 0.82. The cos is the
lowest value that we can reach for the active power drawn.
Determining the available reactive current IQ:
  󰇛󰇜 󰇛󰇜
Determining the reactive power Q available:
    
Determining the absolute current:
 󰇛 󰇜
It is recommended that the device is protected using 3NE1448-2 (850A) fuses. The
rated fuse current of 850A is higher than the maximum line current of 663.6A that
occurs, which means that the SINAMICS S150 can supply the reactive power.
3.2.2 Reactive power compensation on the primary side of the transformer
~
=
CU
320-2
SINAMICS DCC Logic
Reactive power compensation
VSM
U, I
3
VSM 10
ProfiNet
Load (ohmic- inductive,
ohmic-capacity)
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Example 1
A reactive power shall be compensated for by 700 kvar inductively in the medium-
high voltage. This shall be carried out via a transformer from the low voltage. No
further Mo/Mo’s are connected to the ALM in this example. The following
transformer data sheet shows:
Transformer data
Primary voltage
U1
22 kV
Secondary
voltage U2
420 V
uk
6 %
Apparent power
Sn
0,96 MVA
No-load losses
Po
2,1 kW
Load losses
Pk
11 kW
No-load current
Io
3,3 A
By the inductive shunt arm of the transformer a part of the capacitive reactive
power falls. In the first step must be determined, how much additional reactive
power has to be provided. First of all the required reactive power has to be
calculated.
 
 
 
In the next step the impedance Z1K is determined. This represents the inductive
resistance in the shunt arm and is related to the primary side of the transformer.
 
 
 
With the help of the impedance and the current can be determined the reactive
power over the single rope and then it is possible to found out the complete
reactive power of the transformer.
QStr.Trafo
 
18,37A
*30,25=10,21kvar
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Qges.Trafo

= 3*10,21kvar= 30,63kvar
The result has to be added to the required reactive power.
QALM=Qkomp+Qges.Trafo=700kvar+30,63kvar=730,63kvar
The next step is to determine, how highly the voltage can be raised on the
secondary side of the transformer. First of all the value uR must be determined with
triangle formal.
 
 
 
After the value uR has been determined, the value ux also can be calculated.
    
In the next step both determined values will be inserted into the formal. In addition
it has to be considered that the capacity reactive power has an angel of -90°. The
following steps show the results:
󰇛󰇜  
󰇛󰇜

󰇛
󰇜  
󰇛󰇜  
󰇛󰇜  󰇛󰇜 

 
󰇛 󰇜 󰇛󰇜  󰇛 󰇛󰇜󰇜
󰇛 󰇜  󰇛󰇜  󰇛 󰇜-
 󰇛 󰇜
 󰇛 󰇛󰇜 
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Zulässiger
Netzstrom
1,00
0,95
0,90
0,85
0,80
0,75
0,00 cosφ
1,00 0,80 0,60 0,40 0,20 0,00
In the case the ALM will be operated with pure reactive power, the derating factor
of 25 % has to be considered. This means that the ALM has covered a rated
current of at least AC 1283 A by current of 961.76 A. The ALM with MLFB-Number
6SL3330-7TE41-4AA3 has a nominal current of 1405 A and therefore this would
be the suitable device.
Permitted
grid voltage
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Example 2:
An inductive reactive power shall be compensated for by 500 kvar in the
superimposed voltage level and an active power shall be taken of 650 kW
simultaneously. Therefor the ALM will be overexcited operated. The result of
overexcited operation is that the ALM behaves like a condenser.
Der Transformator hat die folgenden Daten:
Transformer data
Primary voltage
U1
6,3 kV
Secondary voltage
U2
720 V
uk
6 %
Apparent power
Sn
0,96 MVA
No-load losses
Po
1,9 kW
Load losses
Pk
9,4 kW
No-load current
Io
3,3 A
In these calculation steps the current is determined from the apparent power.
With the current and the impedance of the transformer can be determined the
reactive power, which remains in the transformer. This reactive power must be
added up to the 500 kvar. The angle is also still determined between active and
reactive power.
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The voltage is determined on the secondary side from transformer with the
apparent power and the angle. Out of the voltage on the secondary side of the
transformer and the apparent power the current can be determined.
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In the first step the cos of 0.77 was calculated. Afterwards it is possible to select
correct ALM. The below diagram shows the derating curve and provides a derating
factor of 0.87 with cos 0.77. Therefore the ALM has to designed for an input
current of 760 A. The ALM with the MLFB 6 SL 3330-7 TG41 0 AA3 is suitable for
this application with 1.1 MW.
3 Solution
Application description ALM
Entry-ID:
https://support.industry.siemens.com/cs/ww/en/view/105643094, V1.0, 10/2016
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It has to be checked by the increased grid voltage, how far the intermediate circuit
voltage rises. Especially it is important for the isolation system of the motor to avoid
overtaxed. It is also important for the du/dt filter that the maximum voltage won’t be
exceeded in continuous operation of 1080V (690 V devices). If it comes to a
durable rising of the voltage, such a filter cannot be used. In addition it should be
possible to provide 230 V with UPS.
3.3 Hard- and software components
3.3.1 SINAMICS HW components
In the case that the application reactive current compensation is used in
connection with a SINAMICS S 150, then it is not obvious from the catalogue
D21.3 which Active Line Module (ALM) is obstructed. The type performance
specification refers only to the Motor Module of the SIMANCS S 150. The table
below gives an overview about the obstructed ALM with SINAMICS S150.
SINAMCIS S150
Voltage level 380V up to 480V
Power Motormodul [kW]
Power ALM [kW]
Rated input current IN
ALM [A]
110
132
210
132
132
210
160
235
380
200
235
380
250
300
490
315
380
605
400
500
840
450
500
840
560
630
985
710
900
1405
800
900
1405
Permitted
grid voltage
3 Solution
Application description ALM
Entry-ID:
https://support.industry.siemens.com/cs/ww/en/view/105643094, V1.0, 10/2016
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Voltage level 500V up to 690V
Power Motormodul [kW]
Power ALM [kW]
Rated input current IN
ALM [A]
75
150
140
90
150
140
110
150
140
132
150
140
160
330
310
200
330
310
250
330
310
315
330
310
400
560
575
450
560
575
560
560
575
710
800
735
800
1100
1025
900
1100
1025
1000
1100
1025
1200
1400
1270
The overview is only applicable if Option L04 was not selected.
Notice: further devices as S 120 ALM:
https://w3app.siemens.com/mcms/infocenter/dokumentencenter/ld/InfocenterLangu
agePacks/katalog-d21-3/sinamics-s120-s150-katalog-d21-3-de-2014.pdf
Additional HW:
VSM 10
Stepdown Transformer for the voltage coverage at the middle voltage level
Current transformer suitable to the device current
3.3.2 SW- components
This Application can be realized with the Standard S 120 SW. In addition, a SW
solution is required with SINAMICS DCC if applicable to determine the gird value
and to generate the reactive current rated value.
For example project with SINAMICS DCC:
http://support.automation.siemens.com/WW/view/de/57886317
4 Contact
Application description ALM
Entry-ID:
https://support.industry.siemens.com/cs/ww/en/view/105643094, V1.0, 10/2016
22
Siemens AG Copyright year All rights reserved
4 Contact
Siemens AG
Industry Sector
PD LD S SAPP 2
Vogelweiherstr. 1-15
90441 Nürnberg