Xu Shuang
Ankerui Electric Co., Ltd. Â Â Â Jiading 201801
1 Overview
Frequency conversion technology has an irreplaceable position in the energy saving of a large number of inductive loads. The saved energy can sometimes reach more than 30%, and the benefits are considerable. With the increasing popularity and application of frequency converters, their proportion of the total power grid load is also increasing. Most of the rated voltages are three-phase 380V AC/DC type inverters. However, the power grid harmonic problems brought about by it are also getting more and more attention from users and power supply departments of various frequency converters. Because the rectification part of the frequency converter is generally three-phase full-wave uncontrollable rectification, the DC loop uses large capacitors as filters. In this way, although the inverter's input voltage waveform on the grid side is basically a sine wave, the input current pulse-type charging current is rich in harmonics. It is shown on the side of the network as 5, 7, 11, 13, 17, and 19 Subharmonic currents are generally dominated by 5, 7, and 11 times. The inductive load needs to consume a large amount of reactive current during operation, but the harmonics will make the reactive power compensation device unable to work normally, and cause some modern precision control machine tools to fail to operate. Therefore, the harmonic control of the system using the frequency converter is necessary. For the inverter's working characteristics, Shanghai Ankerui Electric Co., Ltd. designed the ANAPF active power filter compensation device, which can not only filter the harmonics generated by the frequency conversion device, but also perform reactive power compensation to the system to meet the majority of the use of frequency conversion User needs.
2 ANAPF active power filter features
DSP + FPGA all-digital control , with a very fast response time; advanced main circuit topology and control algorithms, higher accuracy, more stable operation; a machine more than one, can not only make up for harmonics, but also make up for reactive power ; Modular design, easy production debugging; convenient parallel design, convenient expansion; with perfect bridge arm over-current, protection; easy to use, easy to operate and maintain. 3 ANAPF active power filter device parameters
Wiring
Three-phase three-wire or three-phase four-wire
Access voltage
3×380V ±10%
Access frequency
50Hz ±2%
Dynamic compensation response time
Dynamic response <4ms, full response time <20ms;
On-off level
10kHz
Function settings
Only harmonics are compensated, only reactive power is compensated, both harmonics are compensated and reactive power is compensated; manual and automatic switching are performed.
Harmonic compensation times
2-21 times
Type of protection
DC over-voltage IGBT over-current device temperature protection
Overload protection
Automatic current limit in the set value, no overload occurs
cooling method
Smart air cooling
noise
< 65db (in the cabinet and operating in the rated state)
Working temperature
-10°C to +45°C
Working environment humidity
<85%RH non-condensing
Installation occasion
Indoor installation
Altitude
≤1000m (for use at higher altitudes)
Incoming and outgoing ways
Down in and out
Protection level
IP21
Intelligent communication interface
RS485/MODBUS-RTU
Remote monitoring
Optional
Overall size (mm)
(W×D×H)
30A
50A
75A
100A
600×500×1500
600×500×1500
600×500×1800
800×600×2200
Weight (kg)
Three-phase four-wire
Three-phase three-wire
30A, 50A
75A, 100A
30A, 50A
75A, 100A
280
360
240
290
4 Significance of harmonic control and reactive power compensation of power grid
With the wide application of frequency converters, the significance of harmonic power management and reactive power compensation of frequency converter power supply systems has been gradually recognized by people. Inverter power supply can be decomposed into fundamental active current, fundamental reactive current, harmonic and interharmonic current according to Fourier series.
In a workshop with a large amount of inverters, direct reactive power compensation with capacitors can greatly reduce the fundamental reactive current, but harmonic amplification will inevitably occur. At this time, the harmonics and interharmonic currents in the supply current and the capacitor current are greatly increased, the capacitor is damaged due to over-temperature and overvoltage, and the temperature rise of the power supply transformer is increased. In order to avoid harmonic amplification, harmonic control and reactive power must be performed simultaneously.
Sewage treatment plant power equipment mainly pumps, agitators, blowers and other loads. Fans and pumps generally require frequency conversion , and the inverter is a very large harmonic source , so it brings serious harmonic pollution and harmonic interference to the system , resulting in the system can not work normally , and often the electrical components are burned out. . At the same time, there are many power electronic components in the system , such as  UPS, power switches, are harmonic generation device.
Background: a sewage treatment plant substation load is mainly composed by the inverter, inverter driven by the corresponding motor, are all due to the drive load, so bring very serious harmonic pollution and harmonic interference to the system, resulting in The system does not work properly , and electrical components are often burned out . In order to solve the problem , harmonics must be treated.
After researching the field test results, the technical staff of Shanghai Ankerui Electric Co., Ltd. decided to use an ANAPF100-400/B active power filter cabinet for on-site compensation. The installation diagram is as follows:
â— Project effectiveness
It can be seen from the figure, after ANAPF100-400 / B APF counters into operation, power quality has been significantly improved, the harmonic current is greatly reduced, the grid current harmonics are substantially filtered out, the current waveform has Close to a sine wave, the current distortion rate is reduced from 65.5% to 13.4%, and the 5th harmonic is reduced from 61.3A to 4.9A.
ANAPF active filter quotation and list of major components
Model Number: ANAPF100-400/B
Reference price: 120,000 yuan/set
The main product details:
No.
Name
Model number
Quantity
1
APF electrical cabinet
800X600X2200
1
2
Converter
APFCOV-CVT100
1
3
Controller
APFMC-C100
1
4
Reactor
APF-RE.(S)DG-100
1
5
Active current transformer
LT208-S7
3
6
filter
DL-1TH1
2
7
breaker
CVS160FTM160D4P3D
1
8
Contactor
LC1D150M7C
1
9
MCB
NDM1-63C32
1
10
Intermediate relay
MY4NAC
2
11
R type transformer
R320-0.38/0.22
1
12
Harmonic Detector
ACR350EGH
1
13
wire
16mm 2
Some
14
wire
4mm 2
Some
Conclusion: Like many occasions inverter, harmonic conversion mechanism pumps, fans and other equipment generated, causing serious harm to the system transformer, electrical equipment and a capacitor compensation unit and the like. Causes mechanical vibration, noise, and overheating of the motor , causing severe overheating of the transformer, overheating of capacitors, cables, etc. , aging of the insulation , and shortening of life and damage. As can be seen from the above data, the filters before and after the operating power grid current changes very significantly, achieve the purpose of eliminating current harmonics, improve the power supply voltage. Makes the system cleaner and more stable.
ã€references】
[1] Ancorui Electric Co., Ltd. Product Manual. 2013.01.
About the Author:
Xu Shuang, female, undergraduate, Ankerui Electric Co., Ltd., the main research direction for the smart grid power distribution, Email: Mobile QQ
"AAPF Active Power Filter Device Design and Application Atlas" (atlas number: ACR13CDX701) is edited by Ankerui Electric Co., Ltd. This atlas combines the characteristics of ANAPF active power filter device products, based on electrical design specifications, research Eliminating the problem of high-order harmonics in the power supply and distribution system to achieve the goal of improving the quality of power supply and ensuring the safe operation of the power system. The Atlas is applicable to the design and modification of harmonic suppression and comprehensive management of electrical equipment in industrial, civil, and public buildings in new construction, reconstruction, expansion, and technological transformation projects. If you need atlas, please provide your organization's name, department, address, zip code, contact person, contact telephone number, email address, fax 021-69155331, email or QQ to Ankeru Xu cream engineer, Ankerui Electric will give you a free gift.
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