Be applicable to the intelligence filter harmonic energy saving device of intermediate frequency furnace
Technical field
The present invention relates to a kind of filter harmonic device, be specifically related to a kind of intelligence filter harmonic device energy-conservation, that be applicable to intermediate frequency furnace.
Background technology
Along with metallurgy industry by the transformation to electric furnace of the blast furnace (furnace cupola) of fire coal, particularly intermediate frequency furnace is in the application of metallurgy industry, the intermediate frequency power supply of a large amount of intermediate frequency furnaces is in the process of carrying out frequency translation, current distortion rate reaches about 30%, voltage distortion rate about 10%, the conversion meeting of electric current causes the power network current distortion, affect the power supply quality of electrical network, the mains supply quality descends, the electrical network supplementary load loss increase thereby make, power consumption equipment loss increase, the lost of life in also can causing simultaneously netting have a strong impact on the normal operation of peripheral electrical equipment.
Passive filter, junction filter and three kinds of modes of active filter are mainly taked in the improvement of intermediate frequency furnace harmonic pollution at present, and all parallel connection in the line.In these three kinds of modes, can only be targetedly 5 times and 7 subharmonic be administered for front two kinds, behind its harmonic wave control, current distortion rate reaches about 15%, harmonic current still can not reach 12% requirement, harmonic voltage is not had regulation effect substantially, more can not satisfy the standard-required less than 5%, effectively harmonic carcellation; Although active power filtering mode good wave filtering effect, harmonic content accounts for about 10% behind the harmonic elimination, has the shortcomings such as expensive, that failure rate is high, volume is large.
In addition, also there is the low problem of power factor in many domestic intermediate frequency furnaces, when adopting reactive power compensation, because the intermediate frequency furnace load variations is more frequent, so, can cause that the capacitor automatic switching acts frequently, the capacitor influence from harmonic is large, impulse current, and life-span, capacity attenuation are fast.
Summary of the invention
For solving the deficiencies in the prior art, the object of the present invention is to provide and a kind ofly can effectively eliminate the harmonic wave that intermediate frequency furnace equipment produces when frequency translation, and surge current suppression, raising power factor (PF), guarantee the filter harmonic energy saving device of electrical network quality, and this filter harmonic device can be realized Based Intelligent Control to capacitor switching.
In order to realize above-mentioned target, the present invention adopts following technical scheme:
A kind of intelligence filter harmonic energy saving device that is applicable to intermediate frequency furnace, it is characterized in that, comprise: harmonic main frame, the first contactor, the second contactor, reactor, capacitor, intermediate frequency power supply, instrument transformer and programmable controller, the input of aforementioned harmonic main frame is connected with three phase mains, output is connected with intermediate frequency power supply; Aforementioned the first contactor is in parallel with the harmonic main frame; The output of aforementioned reactor is connected with capacitor, input is connected with the second contactor, and the input of the second contactor is connected with the output tap of harmonic main frame again, the wiring of the inner employing of aforementioned capacitor triangle connected mode; The output of harmonic main frame have U V three lines of W, aforementioned instrument transformer is connected on the V line; The input of aforementioned programmable controller is connected with instrument transformer, output switch is connected on the control coil of the second contactor.
The aforesaid intelligence filter harmonic energy saving device that is applicable to intermediate frequency furnace is characterized in that aforementioned reactor is the three-phase tuning reactor.
Preferably, the reactance Rate of aforementioned three-phase tuning reactor is 5-16%.
More preferred, the reactance Rate of aforementioned three-phase tuning reactor is 7%.
The aforesaid intelligence filter harmonic energy saving device that is applicable to intermediate frequency furnace is characterized in that aforementioned intermediate frequency power supply is the intermediate frequency power supply of three-phase six impulse commutations.
The aforesaid intelligence filter harmonic energy saving device that is applicable to intermediate frequency furnace, it is characterized in that, also comprise: electric power monitoring instrument, the voltage sample line of aforementioned electric power monitoring instrument is connected on the input of harmonic main frame, the current sample line is by the rear access of instrument transformer conversion, and aforementioned instrument transformer is through on the output of three phase mains.
Preferably, aforementioned electric power monitoring instrument has data transmission module.
Usefulness of the present invention is: series connection harmonic main frame can effectively stop intermediate frequency furnace to produce before intermediate frequency power supply harmonic current and harmonic voltage transmit to electrical network, then in the output tap of harmonic main frame by the second contactor control connection reactor and capacitor by programmable controller Based Intelligent Control, form the LC filter circuit, the flow-guiding channel of the harmonic wave of an intelligence can be provided, a large amount of harmonic waves that intermediate frequency power supply produces are cancelled out each other by the coupling of reactance and electric capacity; When cancelling out each other, both can avoid when intermediate frequency furnace is not worked, devoting oneself to work for a long time the merit that causes because crossing the benefit phenomenon because of filtering capacitor, and can avoid again causing the frequent problem of switching of capacitor because of merit because of control mode.
Description of drawings
Fig. 1 is the electrical block diagram of a specific embodiment of the present invention's intelligence filter harmonic energy saving device of being applicable to intermediate frequency furnace;
Fig. 2 (a) and (b) are respectively to install voltage, the current waveform figure that the present invention filters the front intermediate frequency furnace of harmonic device additional;
Fig. 3 (a) and (b) are respectively to install voltage, the current waveform figure that the present invention filters intermediate frequency furnace behind the harmonic device additional;
The implication of Reference numeral among the figure: 1-harmonic main frame, 2-the first contactor, 3-the second contactor, 4-reactor, 5-capacitor, 6-intermediate frequency power supply, 7-instrument transformer, 8-programmable controller, 9-electric power monitoring instrument, 10-three phase mains.
Embodiment
Below in conjunction with the drawings and specific embodiments the present invention is done concrete introduction.
With reference to Fig. 1, the intelligence filter harmonic energy saving device that is applicable to intermediate frequency furnace of the present invention comprises: harmonic main frame 1, the first contactor 2, the second contactor 3, reactor 4, capacitor 5, intermediate frequency power supply 6, instrument transformer 7 and programmable controller 8.The concrete connected mode of each device is as follows:
The input R of harmonic main frame 1 S T and three phase mains 10 A B C be connected, output U V W and intermediate frequency power supply 6 L1 L2 L3 be connected, harmonic main frame 1 forms series relationship with intermediate frequency power supply 6; The two ends of the first contactor 2 respectively with the input R of harmonic main frame 1 S T, output U V W be connected, the two forms relation in parallel; The output U1 of reactor 4 V1 W1 and capacitor 5 three binding post a b c be connected, input R1 S1 T1 be connected with the output of the second contactor 3, the input of the second contactor 3 again with the output tap CR of harmonic main frame 1 CS CT be connected, wherein, capacitor 5 inner employing triangle connected mode wiring; The output of harmonic main frame 1 have U V three lines of W, instrument transformer 7 is connected on the V line; The input of programmable controller 8 is connected with instrument transformer 7, and is concrete, and the L of instrument transformer 7 and K are connected on the I+ and I-of programmable controller 8, and the output switch of programmable controller 8 is connected on the control coil of the second contactor 3.
As a kind of preferred scheme, reactor 4 is the three-phase tuning reactor, and more preferably, the reactance Rate of this three-phase tuning reactor is 5-16%, and is wherein best take the result of use of the three-phase tuning reactor of reactance Rate as 7%.
As a kind of preferred scheme, intermediate frequency power supply 6 is the intermediate frequency power supply of three-phase six impulse commutations.
In the present invention, first contactor 2 in parallel with harmonic main frame 1 can switch to city's electricity condition work in the filter circuit fault or when safeguarding, thereby makes intermediate frequency furnace can not affect normally carrying out of manufacturing schedule because filter circuit quits work; Electric current when instrument transformer 7 is used for measuring filter circuit work, and electric current inputed to programmable controller 8, programmable controller 8 compares electric current and the setting electric current that instrument transformer 7 measures, determine whether the second contactor 3 starts, like this can be according to the size of electric current, automatically, the control of intelligence be connected on harmonic main frame 1 output tap CR CS the work in LC filtering compensation loop on the CT and the action of power factor compensation part, this LC filtering compensation loop is comprised of filtering compensation reactor 4 and capacitor 5.Owing to be Current Control, when current value reaches set point, start the LC filtering compensation circuit, the problem of both having avoided the LC filtering compensation circuit when intermediate frequency furnace is not worked, to work on, also make power factor compensation capacitance can not occur with the variation of external load to mend or few action switching of mending, reduced the phenomenon of capacitor 5 frequent switchings.
In order better to monitor the effect of filter harmonic energy saving device, filter harmonic energy saving device of the present invention also comprises: electric power monitoring instrument 9.Electric power monitoring instrument 9 is installed on the input of harmonic main frame 1, its voltage sample line be connected on harmonic main frame 1 input R S on the T, the current sample line is by access after instrument transformer (not shown) conversion, this instrument transformer be through three phase mains 10 output terminals A B on the C.Behind the access electric power monitoring instrument 9, can be real-time, effectively will filter operating state, the electric power data test of harmonic energy saving device and showing, for operating personnel or equipment personnel observation with whether judgment device works, whether the electric power data of intermediate frequency furnace work normal.
As a kind of preferred scheme, electric power monitoring instrument 9 has data transmission module, and the data communication device that its test obtains is crossed data transmission module can realize intelligence transmission, remote monitoring.
Intelligence filter harmonic energy saving device of the present invention has harmonic elimination concurrently, reduce surge and improve the effect of power factor, harmonic elimination after-current aberration rate drops to below 10%, the voltage distortion rate drops to below 5%, voltage waveform and current waveform are proofreaied and correct for sinusoidal wave, specifically referring to Fig. 2 (a) and (b) and Fig. 3 (a) and (b); Intelligence filter harmonic energy saving device of the present invention also has the characteristics such as failure rate is low, reasonable price, capacity are large, and capacity can reach 175KW-6000KW; Simultaneously, because the capacitor of intelligence filter harmonic energy saving device absorbs the harmonic wave effect except having compensation, also the power factor of system compensated, thereby the power factor of system is remained at more than 0.95.
Need to prove that above-described embodiment does not limit the present invention in any form, all employings are equal to replaces or technical scheme that the mode of equivalent transformation obtains, all drops in protection scope of the present invention.