Power Quality Filter
ABB Jumet
Table of contents
1. SAFETY INSTRUCTIONS ... 5
2. UPON RECEPTION ... 6
2.1. DELIVERY INSPECTION... 6
2.2. IDENTIFICATION TAG... 6
2.3. STORAGE... 6
2.4. LONG STORAGE PERIOD AND REFORMING... 6
3. PQFL PRINCIPLE AND CHARACTERISTICS ... 7
3.1. REASONS FOR LIMITING HARMONICS... 7
3.2. GENERAL PRINCIPLE OF ACTIVE FILTERING... 8
3.3. THE ABB ACTIVE FILTER: THE PQFL... 9
3.4. THE PQFL: PERFORMANCES... 11
3.4.1. Filtering ... 11
3.4.2. Reactive power... 12
3.4.3. EMC ... 12
4. COMPONENTS DESCRIPTION AND IDENTIFICATION ... 13
4.1. COMPONENTS DESCRIPTION... 13
4.1.1. PQF current generator... 13
4.1.2. The control ... 14
4.2. COMPONENTS IDENTIFICATION... 15
5. MECHANICAL INSTALLATION ... 21
5.1. GENERALITIES... 21
5.2. IP00 PLATE... 23
5.2.1. Mounting of the plate ... 23
5.2.2. Master cubicle door accessories... 24
5.2.3. Slave cubicle door ... 24
6. ELECTRICAL INSTALLATION ... 25
6.1. OVERVOLTAGE... 25
6.2. POWER CABLES AND EXTERNAL PROTECTION... 25
6.3. CURRENT TRANSFORMERS/CONTROL CABLES SELECTION... 28
6.4. CURRENT TRANSFORMERS INSTALLATION... 30
6.4.1. CT’s connection to the PQFL... 30
6.4.2. CT’s connection topology: cases... 32
6.4.2.1. Case 1: Global compensation – one feeding transformer ...32
6.4.2.2. Case 2: Individual compensation – one feeding transformer ...33
6.4.2.3. Case 3: global compensation – transformer busbar not accessible....34
6.4.2.4. Case 4: two independent feeding transformers. ...36
6.4.2.5. Case 5: back up generator ...38
6.5. CONNECTION OF LAMPS AND BUTTONS (IP00 VERSION) ... 39
6.6. PRECAUTIONS WITH CAPACITORS... 39
7. MASTER-SLAVE INTERCONNECTIONS ... 41
7.1. INTRODUCTION... 41
7.2. MECHANICAL INSTALLATION (CUBICLE VERSION) ... 41
7.3. ELECTRICAL CONNECTIONS... 42
7.3.2.1. Power connection... ... ... ... ... 44
7.3.2.2. Protective earth ... ... ... ... ... 44
8. PQF-PROG INSTALLATION AND PC CONNECTION ... 46
8.1. SYSTEM REQUIREMENTS... ... ... ... 46
8.2. INSTALLING PQF-PROG ON YOUR PC ... ... ... 46
HARDWARE CONNECTION... ... ... ... 46
9. COMMISSIONING...47
9.1. STEP 1 ... ... ... ... ... 47
9.2. STEP 2 ... ... ... ... ... 47
9.3. STEP 3 ... ... ... ... ... 48
9.3.1. PQF connection diagram ... 48
9.3.2. Material needed & hypotheses for correct measurements ... 49
9.3.3. Checking the correct connection of the CTs with a two channel scopemeter... 49
9.3.3.1. Measurement of CT in phase L1... ... ... ... 49
9.3.3.2. Measurement of CT in phase L2 and L3... ... ... ... 51
9.3.4. Checking the correct connection of the CTs with two current probes. ... 52
9.3.5. Checking the correct connection of the CTs with a Fluke 41B... 52
9.4. STEP 4 ... ... ... ... ... 53
9.4.1. With PQF-Prog ... 53
9.4.2. With the PQF-Manager... 54
9.5. STEP 5 ... ... ... ... ... 55
9.6. STEP 6 ... ... ... ... ... 55
9.7. STEP 7 ... ... ... ... ... 55
9.8. STEP 8 ... ... ... ... ... 55
10. OPERATION... 57
10.1. NORMAL WORKING SEQUENCE... ... ... ... 57
10.2. OPERATION WITH CAPACITORS... ... ... ... 62
10.3. BEHAVIOR IN CASE OF POWER OUTAGE... ... ... 62
10.4. BUTTONS, LIGHTS AND LED’S SIGNIFICATION... ... ... 63
10.4.1. Master cubicle. ... 63
10.4.2. Slave cubicle ... 63
10.4.3. PQF-Manager... 64
10.4.4. Control rack... 65
10.5. PROGRAMMING WITH PQF-PROG... ... ... ... 66
10.5.1. Filter operation principle... 66
10.5.2. Starting... 67
10.5.3. Programming the filter... 69
10.6. PROGRAMMING WITH PQF-MANAGER... ... ... 71
10.6.1. Filter operation principle... 71
Keys identification... 72
10.6.3. Programming the filter... 73
10.7. PQFL AND NETWORK MONITORING WITH THE PQF-MANAGER... ... 77
10.7.1. Filter status... 77
10.7.2. Network status... 78
10.7.3. Waveform... 79
10.7.4. Spectrum... 80
10.8. REMOTE CONTROL AND ALARM CONTACT... ... ... 81
10.8.1. Remote control ... 81
10.8.2. Alarm contact... 82
10.9. PROTECTIONS... ... ... ... . 82
11. FAULT HANDLING AND TROUBLESHOOTING... 83
11.1. FAULT HANDLING... ... ... ... 83
11.1.1. Type of faults... 83
11.1.2. Fault handling and fault clearance procedure... 83
11.2. TROUBLESHOOTING... ... ... ... 86
11.2.1. Frequent problems occurring at commissioning stage... 86
11.2.2. Error codes meaning... 86
11.2.3. Faults not related to error codes... 90
11.2.4. Restarting the filter after fault correction... 90
12. MAINTENANCE...91
12.1. MAINTENANCE FREQUENCY... ... ... ... 91
12.2. MAINTENANCE PROCEDURE... ... ... ... 91
12.3. FAN... ... ... ... ... 92
12.4. CAPACITORS REFORMING... ... ... ... 92
1. Safety instructions
These safety instructions are intended for all work on the PQFL.
Neglecting these instructions can cause physical injury and death.
All electrical installation and maintenance work on the PQFL should be carried out by qualified electricians.
Do not attempt to work on a powered PQFL.
After switching off the mains, always wait at least 5 minutes before working on the unit in order to allow the discharge of DC capacitors through the discharge resistors.
DC capacitors might be charged to more than 1000V.
Before manipulating current transformers, make sure that the secondary is short-circuited. Never open the secondary of a loaded current transformer.
You must always wear isolating gloves and eye-protection when working on electrical installation. Also make sure that all local safety regulations are fulfilled.
2. Upon reception 2.1. Delivery inspection
Each PQFL is delivered in a sealed package designed to protect adequately the equipment during shipment.
Upon receipt of the equipment, make sure that the packing is in good condition.
After removal of the packing, check visually the exterior and interior of your filter. Any loss or damage should be notified immediately.
Care should be taken to ensure that correct handling facilities are used.
2.2. Identification tag
Each PQFL is fitted with a nameplate for identification purposes. The nameplate includes the type of filter, nominal frequency, voltage and current as well as a serial number and an ABB internal article code.
This information should always remain readable to ensure proper identification during the whole life of the filter.
2.3. Storage
PQFA packing is made for a storage period of maximum six months (transport time included from delivery date EXW ABB Jumet factory). Packing for longer storage period can be done on request.
If your PQFL is not installed once unpacked, it should be stored in a clean indoor, dry dust free and non-corrosive environment. The storage temperature must be between –15°C and 70°C with a maximum relative humidity of 95%, non-condensing.
Before installing and operating your PQFL, you should read very carefully this instructions manual and you should make sure that the information given on the nameplate corresponds to your network.
2.4. Long storage period and reforming
If your PQFL is non-operational or stored for more than one year, the DC capacitors need to be reformed (re-aged). Without reforming, capacitors may be damaged when the filter starts to operate.
The reforming methods are described in chapter 12 (maintenance).
3. PQFL principle and characteristics 3.1. Reasons for limiting harmonics
Power electronics based equipment is the main source of the harmonic pollution in electric networks. Examples of such equipment include drives (AC or DC), UPS’s, welders, PCs, printers etc.
In general, the semiconductor switches in this equipment conduct only during a fraction of the fundamental period. This is how such equipment can obtain their main properties regarding energy saving, dynamic performance and flexibility of control. However, as a result a discontinuous current containing a considerable amount of distortion is drawn from the supply.
Harmonic pollution causes a number of problems. A first effect is the increase of the RMS-value and the peak-value of the distorted waveform. This is illustrated in figure 3.1. that shows the increase of these values as more harmonic components are added to an initially undistorted waveform. The RMS-value and the peak-value of the undistorted waveform are defined as 100 %. The peaks of the fundamental component and the distortion components are assumed to be aligned. It may be seen that the distorted waveform, which contains harmonics up to the 25th harmonic, has a peak value that is twice the value of the undistorted waveform and a RMS-value that is 10 % higher.
Peak: 100 % 133 % 168 % 204 %
RMS: 100 % 105 % 108 % 110 %
Figure 3.1. Evolution of the increase in peak-value and the RMS-value of a waveform as more harmonic components are added
The increase in RMS-value leads to increased heating of the electrical equipment. Furthermore, circuit breakers may trip due to higher thermal or instantaneous levels. Also, fuses may blow and capacitors may be damaged.
kWh meters may give faulty readings. The winding and iron losses of motors increase and they may experience perturbing torques on the shaft. Sensitive electronic equipment may be damaged. Equipment, which uses the supply voltage as a reference may not be able to synchronise properly and either applies wrong firing, pulses to switching elements or switch off. Interference with electronic communications equipment may occur.
100 % H1 + 33 % H3 + 20 % H5 … + 4 % H25
Distorted networks may also cause generators malfunctions.
Overall it may be concluded that an excessive amount of harmonics leads to a premature ageing of the electrical installation. This is an important motivation for taking action against harmonics.
3.2. General principle of active filtering
The active filter measures the harmonic currents and generates actively a harmonic current spectrum in opposite phase to the measured distorting harmonic current. The original harmonics are thereby cancelled. The principle is shown in figure 3.2.
Figure 3.2. Principle of active filtering
The control of the active filter in combination with the active generation of the compensating current allows for a concept that may not be overloaded.
Harmonic currents exceeding the capacity of the active filter will remain on the network, but the filter will operate and eliminate all harmonic currents up to its capacity.
The principle of active filter showing currents and spectra is clarified in Figure 3.3.
PQFA
Supply Load
Fundamental only
- 1 . 3 1 . 3
0 360
- 1 . 3 1 . 3
0 3 6 0
- 1 . 3 1 . 3
0 360
idistortion
icompensation
Figure 3.3. Active filter principle illustrated in time and frequency domains
3.3. The ABB Active filter: the PQFL.
As we have just seen, the active filter is basically a compensating current generator. The most important parts are then the current generator and the control system.
The compensating current is in a first step created by a three-phase Insulated Gate Bipolar Transistors (IGBT) inverter bridge that is able to generate any given voltage waveform with PWM (Pulse Width Modulation) technology. The IGBT bridge uses a DC voltage source realised in the form of a DC capacitor.
The inverter bridge is in fact the same technology than in AC drives.
The generated voltage is coupled to the network via reactors and a small filter circuit. The desired current generator is thereby achieved.
The DC capacitors are loaded actively through the inverter bridge and there is no need of external power source. Obviously, the DC voltage level must always be higher than the peak value of the network voltage in order to be able to inject currents to the network.
To control the active filter the choice stands between open loop and closed loop current control. Under open loop current control, the harmonics currents are measured on the load side of the active filter that computes the required compensating current and injects it into the network.
Closed loop current control as performed by the PQFL is shown in Figure 3.4.
In this topology the resulting current to the network is measured and the active filter operates by injecting a compensating current minimising this resulting current. In this configuration, the filter directly controls its effect on the filtration.
+
=
currentLoad1 5 7 11 13 17 19
-2002040 1 5 7 11 13 17 19
Active Filter current
1 5 7 11 13 17 19
-20
0
20 40
1 5 7 11 13 17 19
Clean feeder current
1 5 7 11 13 17 19
-20
02040 1 5 7 11 13 17 19
WaveformsHarmonics
- 1 . 3 1.3
0 3 6 0
- 1 . 3 1 . 3
0 3 6 0
- 1 . 3 1 . 3
0 360
Figure 3.4. Closed loop control
In addition to being more precise, the closed loop control system also allows for a direct control of the degree of filtering. Furthermore, the closed loop control system ensures that measurement errors do not result in a higher distortion.
To fully exploit the potential of an active filter we need a digital measurement and control system that is fast enough to operate in true real time. We need to be able to track the individual harmonics and control the compensating current according to the requirements of the plant and this with full control at every instant in time. To achieve this, we need advanced Digital Signal Processors, DSP’s.
Among the physical signals needed by the PQFL, the three line currents have obviously to be measured. Standard CTs with 5A secondary are usually sufficient. Those analogue signals must first be acquired, levelled and antialias-filtered before digitalisation. Fast and high precision analogue-to- digital converters are used to create a digital representation of the analogue signals. The digitised signals are then sent to the powerful DSP that controls all measurements and calculations in real time, and builds the PWM references for the inverter. It is another processor, a microcontroller, which handles all digital input/output (including the command of the PWM inverter).
More dedicated to control than to calculations, this microcontroller ensures for instance the closing of the relays and contactors.
One control is needed per PQFL system and can handle more than one power module simultaneously.
Control AF
Target
Measurement Feedback Output
3.4. The PQFL: performances 3.4.1. Filtering
The main requirement for an active filter installed in an industrial installation is to attenuate the harmonics produced by the non-linear loads of the installation.
The ideal active filter should allow the user to choose freely which harmonic components to filter and should offer an adjustable degree of filtering.
It is also worth noting that the total harmonic voltage distortion at the point of common coupling (PCC) is often calculated up to the 40th [1] or the 50th [2]
harmonic. Furthermore, the total number of harmonics that can be filtered determines directly the quality of the resulting current. This is illustrated in figure 3.5., which shows the filtered waveforms obtained by filtering up to different harmonic levels.
(a) Filtering up to the 13th harmonic.
(b) Filtering up to the 25th harmonic.
(c) Filtering up to the 50th harmonic.
Figure 3.5. Waveforms obtained by eliminating the harmonic components of a rectangular periodic signal up to the (a) 13th harmonic,
(b) the 25th harmonic and (c) the 50th harmonic
This figure highlights the need for an active filter that can operate up to sufficiently high harmonic frequencies.
The PQFL can filter simultaneously 20 (15) independent harmonics up to the 50th for 50Hz (60Hz) based networks. The number of harmonics to be filtered as well as their frequencies is completely programmable by the user.
Besides the harmonic selection functionality, the user has also the possibility to specify a filtration level for each selected harmonic. The PQFL will filter the selected harmonics until
by the user and may be different for each selected harmonic. This functionality is especially useful when the objective is to fulfil the requirements of a standard and results in a better use of the available compensation power.
It also allows the installation of active filters on networks already fitted with a fixed passive filter.
We can see that we are very close to the ideal filter: the choice of which harmonic components to filter is free and the degree of filtering is adjustable according to the wishes of the user.
Moreover, all typical harmonics generated by three-phase non-linear loads may be filtered simultaneously.
3.4.2. Reactive power
Besides the filtering functionality, reactive power compensation is also possible with the active filter. Compared to traditional capacitor banks, the reactive compensation of the PQFL is continuous (‘stepless’), fast and smooth (no transients at switching). The compensation can be either capacitive or inductive.
Two types of compensation are available: automatic compensation where a target power factor has to be set, and fixed compensation based on a predefined amount of kvar.
3.4.3. EMC
The PQFL has been verified for compliance with EU (European Union) directives for EMC (electromagnetic compatibility) for operation at 50 Hz and bears the CE-mark to this effect.
When an apparatus is used in a system, EU directives may require that the system is verified for EMC compliance.
4. Components description and identification 4.1. Components description
As already explained, the active filter is basically composed of two parts: the current generator and the control system.
4.1.1. PQF current generator.
The power circuit of the ABB active filter PQF is represented hereafter.
Output Filter
PWM inverter
Main Breaker Power
Lines
+
-
PWM Reactors Preload
The main components are:
- PWM inverter - PWM reactors - Output filer
- Preloading circuit
The current generator is physically organised in power modules, each including a PWM inverter, three PWM reactors and the output filter.
Non-linear load(s) (three-phase or single-phase)
PQF Digital Control
Compensation current Current
measurement
PQF current generator
Each PQFL plate or cubicle contains one power module. Protection is realized through fuses and there is one preloading circuit.
The PWM inverter is composed of DC capacitors and an IGBT inverter bridge.
This system is able to generate any voltage waveform with PWM technology.
The physical layout of a PWM inverter module is shown hereafter. Each PWM inverter is fitted with a local electronic control called the domino board. The domino board is controlled by the central DSP. The domino board is fitted with jumpers noted JP100, JP101, JP102, JP103, JP104, JP105, JP106, JP109 and JP110 (JP107 and JP108 are off). In case of several power modules, only the domino board of the last slave is fitted with jumpers.
The PWM reactors convert the voltage created by the PWM inverter into currents that will be injected in the network.
The output filter consists in line reactors and an RC shunt circuit.
The function of the preloading circuit is to avoid at start-up high inrush currents that could damage the power electronics or create transients in the network.
4.1.2. The control
DC capacitors
Inverter
Heatsink
digitalisation. Fast and high precision anlogue-to-digital converters are used to create a digital representation of the analogue signals. The digitised signals are then sent to the powerful DSP that controls all measurements and calculation in real time, and builds the PWM references for the inverter. It is another processor, a microcontroller, which handles all digital input/output (including the command of the PWM inverter). More dedicated to control than to calculations, this microcontroller ensures for instance the closing of relays and contactors.
One control unit may command up to 4 power modules.
4.2. Components identification
Control
Output filter capacitor
Auxiliary voltage transformer
PQF Manager PWM
inverter
Fan
A more detailed identification is given in the following pages.
The identification hereafter is related to the drawings of the following pages.
Internal views indicate the position of identified components but fixation details are not included. Although visible on the drawings, some components may actually be hidden in the real structure.
Mains connection
F102/103/104: mains fuses K10: mains contactor
Fan
M101: fan motor
K101: fan contactor
Auxiliaries
Q101: breaker for auxiliaries
T101: auxiliary voltage transformer PWM inverter
U11: module
A67: AC voltage board A77: Domino interface A104: DC voltage converter A117: module domino board
Output filter
C1XX Output filter capacitor R11/12/13 Output filter resistor
L1 Line reactor
PWM reactor
L2 PWM reactor
Preloading circuit
Control rack
A111 Digital I/O board
A112 Interface board – IGBT’s and DSP A113 Digital Signal Processor
A119 Interface PQF Manager board A114 Current input board
A115 Analog input board
A116 +24V power supply board U100 Power supply ? 15V U109 Power supply + 5V
X1 Terminal block digital I/O wiring X4 Terminal block current input wiring X2 Terminal block analog input wiring X10 Terminal power supply wiring X6 Terminal current input wiring
Door components
S102 RESET push button
S101 RUN push button
S104 Remote local switch
H101 White lamp: controller connected to supply (auxiliary breaker closed)
H102 Red lamp: MCB closed H103 Green lamp: MCB open
A120 PQF-Manager
Other components
A121 +24V switching power supply B101/102/103 Internal current sensors K104 Alarm contactor
K12 Remote contactor
X5 Terminal block backplane wiring (external CT connection) X12 Terminal signalling wiring
X20 Terminal intercabinets wiring
Master + slave IP00
K11 K101
1.1.1.
K104 Q101
X12
X5
Control rack details
5. Mechanical installation 5.1. Generalities
The PQFL is suitable for indoor installation, on firm foundations, in a well- ventilated area without dust and excessive aggressive gases where the ambient parameters do not exceed the following values:
40°C max;
30°C (average temperature) over 24 hours;
Minimum temperature: +5 °c
Humidity less than 95% RH non-condensing Altitude: max. 1000m without derating.
For units with nominal voltage above 415V, the rear side of the cubicles must be located at least at 100mm from the wall.
PQFL cubicles (IP23 version) have standard dimensions of 600 x 600 x 2150 mm (width x depth x height).
PQFL plates (IP00 version) have standard dimensions of 498 x 400 x 1896 mm (width x depth x height).
Each cubicle or plate is fitted with one power module, its own bottom cable entry, fuses and contactor.
Standard dimensions for PQFL with up to 3 power modules are shown on page 23.
A maximum of 4 power modules may be connected in parallel.
!!!!!!!!!!!!!!!! Only modules of the same ratings may be paralleled !!!!!!!!!!!!!!!!!!!!!!!
CAUTION
The PQFL dissipates significant amounts of heat that have to be evacuated out of the room where the filter is located. Otherwise, you may experience excessive temperature rise.
For proper cooling of the PQFL, a minimum airflow of 610 m3/h of cooling air has to be supplied to the each fan of the unit. Please ensure the air used for cooling is regularly renewed and does not contain conductive particles, significant amounts of dust, or corrosive or otherwise harmful gases.
The cooling air intake temperature cannot exceed 40°C under any operating condition.
The hot exhaust air has also to be properly ducted away.
5.2. IP00 plate
5.2.1. Mounting of the plate
The IP00 mounting plate is to be fixed in your own cubicle by means of the four holes located in the corners of the plate.
The dimensions of the plate and of the holes are given here below.
5.2.2. Master cubicle door accessories
The dimensions of the cut-out to be made on the master cubicle door are represented here below.
There are 6 holes for buttons and lamps (same dimensions) and the cut-out for the PQF-Manager (if delivered). The buttons and lamps are provided with the filter.
The positions of the cutout are those of the IP23 version and are given for indication only.
5.2.3. Slave cubicle door
Two lamps are provided to be installed on slave cubicle doors. The dimension of the cutout is the same than for the master cubicle door (diameter: 23 mm).
6. Electrical installation
Your PQFL is a parallel active filter: it is installed in parallel with the load(s).
Connection implies:
? ? 3 power cables
? ? 3 CT (one per phase)
? ? 6 control wires for the CT
? ? Ground/PE
6.1. Overvoltage
The PQFL is able to withstand continuously an overvoltage (inclusive of harmonics but not transients) of up to 110 % of the rated voltage. Higher voltages than the rated one would imply an operation at limited power of the filter. Since operation at the upper limits of voltage and temperature may reduce its life expectancy, the PQFL should not be connected to systems for which it is known that the overvoltage will be sustained indefinitely.
6.2. Power cables and external protection
Each cubicle is fitted with its own fuses (bottom cable entry) and needs to be individually connected to the supply.
The power cable size should be rated on the basis of X times the nominal current of the corresponding cubicle (one or two power modules) where X is a multiplication factor which allows to take into account the skin effect.
This multiplication factor is the result of an iterative calculation and can be determined by means of the following process:
Important remark: please note that the following process is made to take into account the skin effect only. Other deratings due to local standards and/or installation conditions (as e.g. cables proximity, number of cables connected in parallel,… ) have to be taken into account by the company responsible for the PQF cable connection.
Step 1: as initial value of this iterative process, determine the preliminary cable section on the basis of the nominal current.
Step 2: based on the previously determined cable section, find in the table here below the multiplication factor that must be applied.
Step 3: determine the cable section on the basis of the value of the multiplication factor times the nominal current.
- if the cable section found is equal to the previously found cable section, the process can be stopped.
The cable section is then determined taking into account the skin effect.
(see examples below)
- If the cable section found is bigger than the previously found value, step 2 and 3 have to be repeated until the cable sections are equal (see example below).
Remark: during this process, it can be found that more than one cable per phase is needed. The process has then to be applied on each cable as shown in the example n°3 below.
SeSeccttiioonn 50Hz 60Hz
[mm2] Al Cu Al Cu
16 1.01 1.01 1.01 1.01
25 1.01 1.02 1.01 1.03
35 1.02 1.03 1.02 1.04
50 1.03 1.06 1.04 1.08
70 1.05 1.1 1.06 1.13
95 1.08 1.16 1.10 1.21
120 1.11 1.30 1.15 1.30
150 1.16 1.30 1.21 1.39
185 1.22 1.41 1.28 1.50
240 1.31 1.55 1.40 1.66
300 1.41 1.70 1.52 1.84
Table: Multiplication factors for different cable types
Examples:
Please note that the following examples are given for information only (see important remark above).
Example n°1:
PQF-L 80A 480V 60hz
Step 1: IN = 80A ? cable section (*) = 25 [mm2]
Step 2: multiplication factor for a 25 [mm2] copper cable at 60hz = 1.03 Step 3: I = IN x 1.03 = 80A x 1.03 = 83 A
Step 4: I = 83A ? cable section (*) : 25 [mm2]
This section is equal to the section found in the previous step.
Result : one copper cable of 25 [mm2] per phase
Example n°2:
PQFA-A 155A 480V 60hz
Step 1: IN = 155A ? cable section (*) = 70 [mm2]
Step 2: multiplication factor for a 70 [mm2] copper cable at 60hz = 1.13 Step 3: I = IN x 1.13 = 155A x 1.13 = 175 A
Step 4: I = 175A ? cable section (*) : 95 [mm2]
Step 5: multiplication factor for a 95 [mm2] copper cable at 60hz = 1.21 Step 6: I = IN x 1.21 = 155A x 1.13 = 187,5 A
Step 7: I = 187,5A ? cable section (*) : 95 [mm2]
This section is equal to the section found in the previous step.
Result : one copper cable of 95 [mm2] per phase
Example n°3:
PQFA-B 427A 400V 50hz
Step 1: IN = 427A ? cable section (*) = 300 [mm2]
Step 2: multiplication factor for a 300 [mm2] copper cable at 50hz = 1.70 Step 3: I = IN x 1.70 = 427 A x 1.70 = 726 A
Step 4: I = 726A ? cable section (*) : 2 x 185 [mm2]
Step 5: multiplication factor for a 185 [mm2] copper cable at 50hz = 1.41 Step 6:
I = IN x 1.41 = 427A x 1.41 = 602 A ? which means 301 A per cable Step 7: I= 301 A ? cable section (*) : 185 [mm2]
This section is equal to the section found in the previous step.
Result : two copper cable of 185 [mm2] per phase
(*) given for information only.
If single core cables are used an alloy gland plate is recommended.
6.3. Current transformers/control cables selection
Three CT’s are needed since the PQFL monitors the three phases of the network.
The proper operation of the PQFL does not require any special CT’s. The requirements are minimum:
? ? 5A of secondary
? ? 15 VA minimum for up to 30 meters of 2.5 mm² cable
? ? Class 1 accuracy or better
? ? Ratio limit above maximum line current
In case the CT’s are shared with other loads, the VA burden shall be adapted and the connection of the different loads (including the PQFL) must be in series.
Twin 2.5 mm² control cable is the most suitable for this application.
In order to determine the suitable CT’s for your application, please refer to the following chart.
Maximum rms current of the downstream loads (including starting current of DC drives): X1 = ….. Arms Multiply X1 by 1.6: X2 = …. Arms CT cables > 30 meters ? Select 3 identical CT’s such that: - rating at primary ? X2 - rating at secondary: 5A - Burden ? 15 VA - Class 1 accuracy or better
NO
Section of CT cables: 2.5 mm²? (recommended) Determine the length of CT cables (meters) L = … m X3 = (L x 0.007 x 25) + 10 X3 = … VA Select 3 identical CT’s such that: - rating at primary ? X2 - rating at secondary: 5A - Burden ? X3 VA - Class 1 accuracy or better Determine the length (m) and resistance (?/m)of CT cables (meters) L = … m R = … ?/m X4 = (L x R x 25) + 10 X4 = … VA Select 3 identical CT’s such that: - rating at primary ? X2 - rating at secondary: 5A - Burden ? X4 VA - Class 1 accuracy or better
NOYES YES
6.4. Current transformers installation
Special care has to be taken for the connection and location of the CT’s: it is the most current source of problems occurring at commissioning stage.
WARNING: when connecting the CT’s to the PQFL, the secondaries of the CT’s have to be short-circuited.
First of all, the CT’s have to be positioned for closed loop control: they have to monitor the resulting current after filtering.
The CT’s must also be positioned in the correct direction around the power cable: the K (or P1) side should be in the direction of the supply and the L (or P2) side should be in the direction of the load.
6.4.1. CT’s connection to the PQFL
The connections between the CT’s and the filter must satisfy the following scheme:
? ? The k terminal of line 1 CT is connected to terminal X5-1 of the filter
? ? The l terminal of line 1 CT is connected to terminal X5-2 of the filter
? ? The k terminal of line 2 CT is connected to terminal X5-3 of the filter
? ? The l terminal of line 2 CT is connected to terminal X5-4 of the filter
? ? The k terminal of line 3 CT is connected to terminal X5-5 of the filter
? ? The l terminal of line 3 CT is connected to terminal X5-6 of the filter
L1 L2 L3
Load side Supply side
K L
k l
K L
k l
K L
k l
PQF X5.2
X5.3 X5.4 X5.5 X5.6
X5.1
L1 L2 L3
X5
6.4.2. CT’s connection topology: cases
The location of the CT’s is critical to ensure the proper operation of the active filter. The CT’s are the “eyes” of the filter and it will react in accordance with the information supplied by them.
The location of the CT’s must always be in closed loop configuration. This means that the CT’s must see the load current and the filter current.
In some cases, summation CT’s might be needed to fulfil the closed loop requirement.
Typical circuit topologies and adequate CT’s location are described hereafter in the following order:
Case 1: Global compensation – one feeding transformer.
Case 2: Individual compensation – one feeding transformer.
Case 3: Global compensation – transformer busbar not accessible.
Case 4: Two independent feeding transformers.
Case 5: Back up generator.
Please bear in mind that the active filter always needs 3 CT’s: one per phase.
66..44..22..11.. CCaassee 11:: GGlloobbaall ccoommppeennssaattiioonn –– oonnee ffeeeeddiinngg ttrraannssffoorrmmeerr
This is the most frequent configuration: one transformer feeds several non- linear loads. The active filter is installed in central position and filters the combined harmonic currents.
This configuration and the proper location of the CT’s is represented hereafter.
Figure 6.1. Global compensation – one feeding transformer.
The connection of the CT’s to the active filter must be as represented herafter:
PQF LOAD LOAD LOAD
L1 L2 L3
Load side Supply side
K L
k l
K L
k l
K L
k l
PQF X5.2
X5.3 X5.4 X5.5 X5.6
X5.1
L1 L2 L3
Figure 6.2. CT’s connection to the active filter.
66..44..22..22.. CCaassee 22:: IInnddiivviidduuaall ccoommppeennssaattiioonn –– oonnee ffeeeeddiinngg ttrraannssffoorrmmeerr Instead of installing one active filter in central position, it also possible to connect the active filter and its CT’s so that it compensates one particular load only.
In the example hereafter, the active filter PQF is connected to compensate Load 1 only. It does not see load 2.
Figure 6.3. Individual compensation – one feeding transformer
The connection of the 3 CT’s to the active filter is described in 6.4.1.
LOAD 2
LOAD 1 PQF
K = P1, L = P2, k = S1, l = S2
66..44..22..33.. CCaassee 33:: gglloobbaall ccoommppeennssaattiioonn –– ttrraannssffoorrmmeerr bbuussbbaarr nnoott aacccceessssiibbllee.. The active filter is required to filter the loads of side A and side B but the transformer busbar not being accessible, the CT’s cannot be installed in central position.
Figure 6.4. Transformer busbar with no access: single-line diagram
For this configuration, three CT’s (one per phase) have to be installed on side A et on side B (in total, 6 CT’s). Those CT’s will then feed 3 summation CT’s (one per phase) that are connected to the active filter. This CT topology is represented in figure 6.5.
LOADS (Side A)
LOADS
(Side B) PQF
Figure 6.5. Transformer busbar with no access: CT connection (to be done for each phase)
The CT’s installed in each phase of side A et B (CT1 and CT2) must be identical (X / 5) and feed a summation CT whose secondary is 5A (5+5/5A).
The summation CT is then connected to the active filter in accordance with chapter 6.4.1.
A total of 3 summation CT’s (one per phase) must be used. The CT ratio to be programmed in the filter is: 2X / 5.
The CT – summator – PQF connection is represented here below. This has to be done for each phase.
LOADS
(Side A) LOADS
(Side B)
PQF
Summation CT (one per phase) Primary 1: 5 A Primary 2: 5A Secondary: 5A CT 1 (one per
phase) Primary: X
Secondary: 5A CT 2 (one per
phase) Primary: X Secondary: 5A
Figure 6.6. Connection between CT1, CT2 , the summation CT and PQF for one phase.
6
6..44..22..44.. CCaassee 44:: ttwwoo iinnddeeppeennddeenntt ffeeeeddiinngg ttrraannssffoorrmmeerrss..
Two independent transformers (the tie is normally open) feeds two different set of loads. One active filter is fitted on each LV busbar.
This system may however also work in degraded mode: the tie is closed and only one transformer feeds the whole LV system.
By connecting the CT’s as described hereafter, it is still possible to filter properly the harmonics and to correct the power factor.
PQF PQF
T1 T2
S1, k S2, l
S1, k S2, l
P1 P2 P1 P2
S1
S2
k l
PQF
Side A Side B
P1, K
P2, L
P1, K P2, L
Figure 6.8. Two independent transformers: CT connection for one phase.
For each phase, 3 CT’s must be installed: - one to measure I1 - one to measure I2 - one to measure I0.
Those CT’s must be identical: X/5 A.
CT I1 and CT I0 feed a summation CT which is connected to PQF1.
CT I2 and CT I0 feed a summation CT which is connected to PQF2.
Those summation CT’s must be 5+5 / 5 A.
Condition 1: the tie is open.
PQF1 sees I1 and PQF2 sees I2 (I0 = 0). The two transformers work independently and the total current to be compensated is I1 + I2.
Condition 2: the tie is closed but both transformers feed the loads.
In this configuration, PQF1 sees (I1-I0) and PQF2 sees (I2+I0). The total current seen by the two filters is I1 + I2.
S1, k
S2, l
P1 P2 P1 P2
S1 S2 S1, k
S2, l
S1 k
S2 l
P1 P2 P1 P2
S1 S2
I1 I2
I0
I’1-I’0 PQF 1
I’2+I’0 PQF 2
k l k l
T1 T2
P2, L
P1, K P1, K
P2, L P1
K
P2 L
Condition 3: the tie is closed but only one transformer feeds the loads (degraded mode).
If only T1 feeds the loads with the tie closed, PQF1 sees (I1-I0) and PQF2 sees I0 (I2 is zero). If only T2 feeds the load, I1 will be zero.
The above described connection must be done for each phase. The CT ratio to be programmed in the filter is: 2X/5.
66..44..22..55.. CCaassee 55:: bbaacckk uupp ggeenneerraattoorr
Many installations are fitted with back up generators to ensure the proper operation of the installation in case of mains power outage.
A typical configuration is given here below.
Figure 6.9. Back-up generator: typical single-line diagram
The CT connection must be such that the active filter works whatever the type of supply: generators or transformer-MV network.
For each phase, one CT is installed in the transformer feeding and one in the G
LOAD PQF
Figure 6.10. Back-up generator: CT connection (for one phase)
6.5. Connection of lamps and buttons (IP00 version)
The buttons and lamps have to be connected to terminal X20 according to the following table:
Item Connection points
Green lamp (H103) X20-4 / X20-3 Red lamp (H102) X20-5 / X20-3 White lamp (H101) X20-6 / X20-3
Local-remote switch (S104) X20-7 / X20-8 (local) / X20-9 (remote) Run button (S101) X20-8 / X20-10
Reset button (S102) X20-8 / X20-11
6.6. Precautions with capacitors
In the presence of power capacitors (LV or MV), harmonics below the resonance frequency of the capacitor bank should not be handled by the filter to avoid any risk of resonance. Those harmonics have to be deselected (see chapter 10 on programming the filter).
Networks where the PQFL is installed have large harmonic content and it is highly recommended that capacitor banks be fitted with detuning reactors.
The harmonics below the tuning frequency of the bank have also to be deselected.
The following table indicates the harmonics to be deselected for main types of detuned banks.
S1, k S2, l
S1, k S2, l
P1 P2 P1 P2
S1 S2
k L
PQF G
P1, K
P2, L
P1, K
P2, L
Detuned bank type Harmonics to be deselected
5.67% 2, 3, 4.
6% 2, 3, 4.
7% 2, 3.
14% 2.
For other types of detuned bank or in the case of plain capacitors, please contact your ABB Service provider to evaluate the resonance frequency and the harmonics to be deselected.
7. Master-slave interconnections 7.1. Introduction
This section explains how to connect PQF sections (Master-Slave or Slave- Slave) when they do not come connected from the factory or in case of on-site extension.
The section starts with mechanical installation.
Electrical connections are then described: interconnections between sections and with the supply.
All cables needed to make the connections are supplied with the units.
A maximum of 4 power modules may be connected in parallel.
!!!!!!!!!!!!!!!! Only modules of the same ratings may be paralleled !!!!!!!!!!!!!!!!!!!!!!!
7.2. Mechanical installation (cubicle version)
The side panels of the cubicles to be interconnected have first to be removed (except the outside one of the Master and last Slave cubicles).
The provided divider panel seal has to be fixed on the interior frame between cubicles.
Cubicles are then interconnected at 6 fixation points as indicated in Figure 3.1.
The baying kit is provided with the cubicles (not the tools).
Figure 7.1. Mechanical installation
7.3. Electrical connections
7.3.1. Connections between sections
77..33..11..11.. PPoowweerr ccoonnnneeccttiioonn
The DC bus of the master and slave sections must be connected.
Each slave section comes from the factory with two cables connected on the + and - poles of the DC bus.
Those cables are then fixed to the terminals of the DC bus of the next section.
Be very careful about the polarity when connecting the DC bus.
Figure 7.2. DC bus interconnection
77..33..11..22.. CCoonnttrrooll ccoonnnneeccttiioonn
? ? The following terminals of the master unit and the first slave unit must be interconnected (three interconnections):
Master Slave 1
A X21-1 connected to X21-4 B X21-2 connected to X21-5 C X21-3 connected to X21-6
? ? The following terminals of the first slave unit and the second slave unit must be interconnected (three interconnections):
Slave 1 Slave 2
A X21-1 connected to X21-4 B X21-2 connected to X21-5 C X21-3 connected to X21-6
? ? The following terminals of the second slave unit and the third slave unit must be interconnected (three interconnections):
Slave 2 Slave 3
A X21-1 connected to X21-4 B X21-2 connected to X21-5 C X21-3 connected to X21-6
Master Control
+-
Slave 1
+- +
+ - -
Internal connection External connection to perform
Slave 2
+- +
-
? ? The following terminals of the third slave unit and the fourth slave unit must be interconnected (three interconnections):
Slave 3 Slave 4
A X21-1 connected to X21-4 B X21-2 connected to X21-5 C X21-3 connected to X21-6
77..33..11..33.. DDoommiinnoo bbooaarrddss ccoonnnneeccttiioonn
The inter-domino boards connection is achieved with flat cables.
Each slave section is fitted with a loose flat cable. The other end of this flat cable has to be connected to the first plug of domino board A118 of the next cubicle, starting at the last slave.
Make sure that the plug-in pattern of the connector and plug is respected.
The last domino of the chain must be fitted with termination jumpers on positions JP100, JP101, JP102, JP103, JP104, JP105, JP106, JP109 and JP110 (JP107 and JP108 are off).
An example of domino boards interconnection is given in Figure 7.3 (PQFA- B+D+C).
77..33..11..44.. EEaarrtthh ccoonnnneeccttiioonn
The earth cable of each slave cubicle has to be connected to the earth connection point of the master cubicle. Make sure that the cables run along the floor, not over components.
7.3.2. Connections to the supply
77..33..22..11.. PPoowweerr ccoonnnneeccttiioonn
Three power cables (L1, L2, L3) have to be connected to each circuit breaker (one in each cubicle).
Make sure that L1, L2 and L3 in each cubicle are connected to the same phases.
7
7..33..22..22.. PPrrootteeccttiivvee eeaarrtthh
The protective earth point of each cubicle has to be connected to earth.
Figure 7.3. Flat cables connection and connections to power supply Slave 1
Domino
A118
L1 L2 L3
PE
Control
Master
Domino
A118
L1 L2 L3
PE
Internal connection
External connection to perform
Slave 2
Domino
A118
L1 L2 L3
PE
8. PQF-Prog installation and PC connection
The PQF-Prog, included in the standard PQFL package, allows for the complete programming of the filter. It consists of two Micro Floppy Disks delivered with the filter.
8.1. System requirements
Windows NT 4.0 Service Pack 3 minimum.
At least one free COM:port (RS232 - DB 9).
One standard RS232 cable (male-female non twisted) 8.2. Installing PQF-Prog on your PC
1. Insert disk 1 of PQF-Prog in drive A 2. In the Start Menu, choose Run 3. In the Command Line box enter
a:\setup
4. Follow the instructions in the dialog boxes to:
? ? Specify the drive and directory (c:\ Program Files \ Pqf is the default)
? ? Complete the installation 8.3. Hardware connection
A111 A112 A113 A119 A114 A115 A116 U100 U109
DIG INT DSP GUI LIC LVI ALIM/GND ±15V +5V
1 2
3
2 1 3 2
1 12 12 1
2
1 1 2
3 4 3
RS232-port
If your filter is equipped with the PQF-Manager, you just have to plug the DB 9 connection in the RS232 port situated at the front of the PQF-Manager.
If your filter is not equipped with the PQF-Manager, you have to plug the connection in the RS232 port located on the control rack (A111: digital I/O board) as shown here after.
9. Commissioning
The commissioning of your PQFL should be conducted in strict accordance with the following procedure.
Warning: Before applying the commissioning procedure, make sure that you become familiar with programming instructions (see chapter 10, programming with PQF-Prog and PQF-Manager).
Pay particular attention to the presence of capacitors on the network.
The commissioning procedure consists in 8 steps that should be followed very carefully.
Step 1 Installation check Step 2 Voltage phase rotation Step 3 Current transformer check Step 4 System set-up
Step 5 Before starting the filter Step 6 Start the filter
Step 7 Stop the filter Step 8 Start filtering 9.1. Step 1
Step 1: Visual and installation check
Check first that mechanical and electrical installations fulfil requirements described in chapter 4 and 5 of the present manual.
Check also visually the conditions of the filter and the tightness of connections. In particular, verify that all connections on the control rack, domino board and IGBT are properly plugged in.
9.2. Step 2
Step 2: Voltage phase rotation
Voltage phase rotation must be clockwise (L1 -> L2 -> L3 -> L1). Wrong phase rotation may damage the filter.
9.3. Step 3
Step 3: Current transformer check
Improper CT connection is the most frequent cause of problems during commissioning.
The following procedure will allow you to check the CT connection.
Warning: The secondary circuit of a loaded CT must never be opened otherwise extremely high voltages may appear which can lead to physical danger or destruction of the CT itself.
9.3.1. PQF connection diagram
Figure 9.1. shows the normal connection of the PQF. It must be noted that:
? ? L1, L2 and L3 rotation must be clockwise,
? ? The CTs must be on the supply (line) side of the PQF,
? ? One secondary terminal of the CT must be earthed.
L1 L2 L3
Load side Supply side
K L
k l
K L
k l
K L
k l
PQF X5.2
X5.3 X5.4 X5.5 X5.6
X5.1
L1 L2 L3
It is also seen that terminal X5.1 and X5.2 are related to the CT located in phase L1, terminal X5.3 and X5.4 are related to the CT located in phase L2 and terminal X5.5 and X5.6 are related to the CT located in phase L3.
9.3.2. Material needed & hypotheses for correct measurements
A two channel scopemeter with one voltage input and one current input is needed. Adequate sensors are also needed. A power analyser like the Fluke 41B can also be used.
Some minor knowledge of the load is also required. For instance, the method explained below is based on the fact that the load is inductive and not regenerative (i.e. the load current lags by less than 90° the phase voltage). If a capacitor bank is present, it is better to disconnect it before making measurements in order to ensure an inductive behaviour of the load. It is also assumed that the load is approximately balanced.
9.3.3. Checking the correct connection of the CTs with a two channel scopemeter.
The first channel of the scopemeter must be connected to the phase voltage referenced to the neutral or to the ground if the neutral is not accessible.
The second channel must measure the associated current flowing from the network to the load as seen by the CT input of the PQF.
99..33..33..11.. MMeeaassuurreemmeenntt ooff CCTT iinn pphhaassee LL11
For the voltage measurement (channel 1), the positive (red) clamp must be connected to the phase L1 and the negative clamp (black) must be connected to the neutral (ground).
For the current measurement (channel 2), the clamp should be inserted into the wire connected on terminal X5.1 and the arrow indicating positive direction of the current should point towards the PQF. Do not forget to remove the short on the CT secondary before making the measurement.
L1 L2 L3
Load side Supply side
K L
k l
K L
k l
K L
k l
PQF X5.2
X5.3 X5.4 X5.5 X5.6
X5.1
L1 L2 L3
Positive direction
Ch1 Ch2
Figure 9.2. Connection of the scopemeter for checking CT in phase L1.
On the scopemeter screen, two waveforms should appear. The voltage waveform should be approximately a sine wave1 and the current waveform would normally be a well distorted wave because of harmonic distortion.
Usually, it is quite easy to extrapolate the fundamental component as it is the most important one (Figure 9.3).
I I1
Figure 9.3. Extrapolation of fundmental component from a distorted waveform.
From the fundamental component of both signals, the phase shift must then be evaluated (Figure 9.4). The time ?T between zero crossing of the rising (falling) edge of both traces must be measured and converted to a phase shift
? by the following formula:
? ?
? *360
T1
? T
where T1 is the fundamental period duration.
For an inductive and non regenerative load, the current signal should lag the voltage by a phase shift lower than 90°.
?T
T1
U
I1
Figure 9.4. Phase shift evaluation between two waveforms.
99..33..33..22.. MMeeaassuurreemmeenntt ooff CCTT iinn pphhaassee LL22 aanndd LL33
The same operations as those described in the previous paragraph must be repeated with the phase L2 (Figure 9.5) and phase L3 (Figure 9.6).
For a balanced load (which is usually the case in most of the three phase systems), the phase shift should be approximately the same for all the three phases.
L1 L2 L3
Load side Supply side
K L
k l
K L
k l
K L
k l
PQF X5.2
X5.3 X5.4 X5.5 X5.6
X5.1
L1 L2 L3
Positive direction
Ch1 Ch2
Figure 9.5. Connection of the scopemeter for checking CT in phase L2.
L1 L2 L3
Load side Supply side
K L
k l
K L
k l
K L
k l
PQF X5.2
X5.3 X5.4 X5.5 X5.6
X5.1
L1 L2 L3
Positive direction
Ch1 Ch2
Figure 9.6. Connection of the scopemeter for checking CT in phase L3.
