CN101026303A - Special filter for medium frequency furnace - Google Patents
Special filter for medium frequency furnace Download PDFInfo
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- CN101026303A CN101026303A CNA2007100106932A CN200710010693A CN101026303A CN 101026303 A CN101026303 A CN 101026303A CN A2007100106932 A CNA2007100106932 A CN A2007100106932A CN 200710010693 A CN200710010693 A CN 200710010693A CN 101026303 A CN101026303 A CN 101026303A
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- capacitor
- reactor
- frequency furnace
- intermediate frequency
- filter
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
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Abstract
Being in simple structure, and lower cost, the disclosed dedicated filter is able to filter out most parts of high order harmonic for eliminating pollution on power grid from intermediate frequency furnace basically. The filter is composed of two sets of filtering module. One module consists of parallel-connected three-phase iron core reactor 1 and resistance 3, which is connected to capacitor 2 in series. Series resonance frequency of reactor 1 and capacitor 2 is selected between 200Hz and 500Hz, and numerical value of resistance 3 is selected at 1-3 times of load value of resistance of intermediate frequency furnace. The other module is composed of cascade connected three-phase air core reactor 4, and capacitor 5. Series resonance frequency of reactor 4 and capacitor 5 is selected at 0.7-1 time of high order harmonic of intermediate frequency furnace.
Description
Technical field:
The present invention relates to be used in the electric power system filter of filtering harmonic wave, relate in particular to the filtering of the high order fractional harmonic that intermediate frequency furnace produces.
Background technology:
The high order fractional harmonic that intermediate frequency furnace produced produces serious pollution to electrical network, is the primary pollution source of present Chinese countryside electrical network.
The harmonic wave that intermediate frequency furnace produces comprise 5 times, 7 times ... harmonic wave Deng 2 times of integral frequency harmonizing wave and medium frequency inverter frequencies.Because the medium frequency inverter frequency of intermediate frequency furnace has nothing to do with the power supply work frequency, so the harmonic wave of 2 times of medium frequency inverter frequencies belongs to the mark subharmonic.Again because the reverse frequency of intermediate frequency furnace far above work frequency, therefore is referred to as the high order fractional harmonic with this part harmonic wave.In the harmonic components that intermediate frequency furnace produces mainly is the high order fractional harmonic.The high order fractional harmonic is very serious to the influence of electrical network, and uses the minimill of intermediate frequency furnace to spread all over the place in the rural area at present, therefore becomes the primary pollution source of present Chinese countryside electrical network.
Existing harmonic wave detecting instrument uses the method for Fourier transform to carry out harmonic wave mostly and detects, and the method for Fourier transform can only be used to detect integral frequency harmonizing wave, detection to fractional harmonic is powerless, therefore in most of the cases can not detect accurately, make high order fractional harmonic problem can not get due attention the high order fractional harmonic.Existing harmonic filter method for designing is some groups of integral frequency harmonizing wave filters of design and one group of high pass filter, and this group high pass filter is smooth impedance operator at high band, to the filtration result extreme difference of high order fractional harmonic.Owing to above reason, often after filter had been installed at the intermediate frequency furnace place, although the result that harmonic wave detects meets the requirements, the pollution condition of electrical network did not take a turn for the better.
Summary of the invention:
Simple in structure, the lower-cost filter that the purpose of this invention is to provide a kind of special filtering intermediate frequency furnace high order fractional harmonic, can filtering most of high order fractional harmonic makes intermediate frequency furnace be eliminated substantially the pollution of electrical network.
The present invention uses following technical scheme to realize:
Comprise two groups of filtering units in the described filter, one of them assembly is connected with capacitor 2 by three-phase iron-core reactor 1 parallel resistance 3 again and is constituted, the series resonance frequency of reactor 1 and capacitor 2 is chosen between the 200-500Hz, the 1-3 that the value of resistance 3 is chosen in intermediate frequency furnace load resistance value doubly between, another assembly is connected with capacitor 5 by three-phase air core reactor 4 and is constituted, the 0.7-1 that the series resonance frequency of reactor 4 and capacitor 5 is chosen in intermediate frequency furnace high order fractional harmonic frequency doubly between.
Described reactor 4 belongs to serial band pass filter with the filtering unit that capacitor 5 is formed, its series resonance point is tuned near the high order fractional harmonic frequency that intermediate frequency furnace produces (be medium frequency inverter frequency 2 times), because near the series impedance of series filter resonance point is very low, therefore most of high order fractional harmonic can be filtered out.Because high order fractional harmonic electric current is most of by this group filtering unit, so the current capacity of reactor 4 and capacitor 5 will design by the high order fractional harmonic total content that intermediate frequency furnace produces.When the little and capacitance of the inductance value of series filter is big, the passband broad of filter, add high capacitance so should reduce inductance value as far as possible, result of study shows, has best effect when the inductance value of reactor 4 is chosen as 50% left and right sides of intermediate frequency furnace main transformer leakage inductance amount.Because will flow through very big harmonic current in the reactor 4, the harmonic voltage at its two ends is also higher, and inductance value is less, therefore must use air core reactor.
Described reactor 4 should be a little less than high order fractional harmonic frequency with the series resonance frequency of the band pass filter that capacitor 5 is formed.Though the impedance minimum when the resonance frequency of series filter equals harmonic frequency still needs suitable harmonic voltage and exists, and can flow through harmonic current, so the distortion of the harmonic voltage in the electrical network just certainly exists.When the resonance frequency of series filter during a little less than harmonic frequency, because the series filter oscillating current that disturbance encouraged of intermediate frequency furnace silicon controlled rectifier commutation process is just approaching with the phase place of harmonic current, so filter effect is better on the contrary.Result of study shows, when the resonance frequency of series filter equals 85% left and right sides of harmonic frequency, can obtain best filter effect.
The effect of the described filtering unit of being made up of iron-core reactor 1, capacitor 2, resistance 3 mainly is to reduce low-order harmonic to amplify and reduce the disturbance of intermediate frequency furnace silicon controlled rectifier commutation process to serial band pass filter.The capacitance of capacitor 2 should be approaching with the capacitance of capacitor 5, and current capacity designs by 2 times of the power current that wherein flows through.The current capacity of reactor 1 designs by capacitor 2 current capacities 80%.The current capacity of resistance 3 designs by the current capacity of reactor 1.
Description of drawings
Fig. 1 is a filter embodiment schematic diagram of the present invention
Embodiment
Below in conjunction with description of drawings a kind of embodiment of the present invention:
If the main transformer of certain intermediate frequency furnace is 500KVA, secondary voltage is 520V, and leakage inductance is 80 μ H, load fundamental current 500A, high order fractional harmonic electric current 150A.Then in the present embodiment: the inductance value of reactor 1 is 400 μ H, and current capacity is 40A; The capacitance of capacitor 2 is 300 μ F, and current capacity is 50A; The resistance of resistance 3 is 1.2 Ω, and current capacity is 40A; The inductance value 40 μ H of reactor 4, current capacity is 150A; The capacitance of capacitor 5 is 300 μ F, and current capacity is 150A.
Claims (3)
1. the filter that is used for filtering intermediate frequency furnace high order fractional harmonic that uses in the electric power system, it is characterized in that: comprise two groups of filtering units in the described filter, one of them assembly is connected with capacitor 2 by three-phase iron-core reactor 1 parallel resistance 3 again and is constituted, the series resonance frequency of reactor 1 and capacitor 2 is chosen between the 200-500Hz, the 1-3 that the value of resistance 3 is chosen in intermediate frequency furnace load resistance value doubly between, another assembly is connected with capacitor 5 by three-phase air core reactor 4 and is constituted, the 0.7-1 that the series resonance frequency of reactor 4 and capacitor 5 is chosen in high order fractional harmonic frequency doubly between.
2. compensation arrangement according to claim 1 is characterized in that: the inductance value of described reactor 4 is about 50% of intermediate frequency furnace main transformer leakage inductance amount.
3. compensation arrangement according to claim 1 is characterized in that: reactor 4 is about 85% of high order fractional harmonic frequency with the series resonance frequency of the serial band pass filter that capacitor 5 is formed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100106932A CN101026303A (en) | 2007-03-23 | 2007-03-23 | Special filter for medium frequency furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100106932A CN101026303A (en) | 2007-03-23 | 2007-03-23 | Special filter for medium frequency furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101026303A true CN101026303A (en) | 2007-08-29 |
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ID=38744323
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2007100106932A Pending CN101026303A (en) | 2007-03-23 | 2007-03-23 | Special filter for medium frequency furnace |
Country Status (1)
| Country | Link |
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| CN (1) | CN101026303A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105576662A (en) * | 2014-10-30 | 2016-05-11 | Ls产电株式会社 | Multiple-tuned filter design method for HVDC system |
| CN107615632A (en) * | 2015-07-24 | 2018-01-19 | 三菱电机株式会社 | Power-converting device |
-
2007
- 2007-03-23 CN CNA2007100106932A patent/CN101026303A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105576662A (en) * | 2014-10-30 | 2016-05-11 | Ls产电株式会社 | Multiple-tuned filter design method for HVDC system |
| US9973003B2 (en) | 2014-10-30 | 2018-05-15 | Lsis Co., Ltd. | Multiple-tuned filter design method for HVDC system |
| CN107615632A (en) * | 2015-07-24 | 2018-01-19 | 三菱电机株式会社 | Power-converting device |
| CN107615632B (en) * | 2015-07-24 | 2019-12-06 | 三菱电机株式会社 | power conversion device |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C57 | Notification of unclear or unknown address | ||
| DD01 | Delivery of document by public notice |
Addressee: Liu Luwei Document name: Notification before expiration of term |
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| DD01 | Delivery of document by public notice |
Addressee: Liu Luwei Document name: Notification that Application Deemed to be Withdrawn |
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| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Open date: 20070829 |