The choice of transducer of rectification transformer, intermediate frequency, harmonic is reached to the influence of electrified wire netting restrain measure
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5% when emulation earning. Express brake of 2 homebred brilliant to be in charge of inversion to spark lead horn reference is worth frequency (Hz) 30 ° of 20040010002000400010000 φ 36 ° of 32 ° dc of 46 ° Nextpage ② sheds 42 ° of 38 ° Id and 103/810=2469APa of × of IdqId=Pa / Ud = 2000 -- if transducer rated power is rectification transformer output for 12 pulse, the output dc of bridge of every groups of commutate sheds Idq: × of Idq = Id 0.
6=2469 × 0.
Id of electric current of dc of 6 =1481 A is multiplied with 0.
6 it is to consider two commutate bridge to have 60% with the disequilibrium of 40% . Brake of ③ commutate brilliant is in charge of (KP) brake of brilliant of ④ commutate of =544 A of π of 2/ of × of half average IthIth=1481/ provides electricity (KP) choice [note 1] to choose KP-1000A/2.
5kV, criterion: Abundant of IthI=1000A electric current spends coefficient KI =IthI/Ith=1000/544=1.
84 voltage abundant spends × of × of coefficient KU = 2500/(600 1.
1)=2.
1 what brake of 68 commutate brilliant provides peak value of actual susceptive voltage.
1 times (because of rectification transformer voltage of side of a powerful person may have ± the wave motion of 10% ) . Brake of ⑤ inversion brilliant is in charge of (KK) electric current π of 2/(of × of =2469 of × of half average IthIth= ) the alternative that brake of brilliant of =1111A ⑥ inversion provides [note 2] to choose abundant of KK-2000A/2800V electric current to spend coefficient KI = 2000/1111=1.
80 voltage abundant spends 1039)=1 of × of coefficient KU = 2800/(.
The Ld[of value of inductance of dc filter wave of bridge of each groups of commutate notes 91 ⑦ abundant of 1] electric current spends abundant of coefficient KI, voltage to spend coefficient KU to press experience value to be in commonly 1.
5 ～ 2.
0 between choose. [Note 2] at present condition of compression of 2800V of canal of brake of homebred and fast brilliant falls, electric current can amount to 3500A, if ask the circumstance of taller compression falls, can provide two KK series connection link. Brake canal manufacturer presses Ying Youjing of canal of brake of series connection brilliant to all press requirement choosing to match, assemble in the factory for an organic whole. F of π of Ld=3U/[4 (IM-1.
1Idq) ] × of =3 × 660/[4 π 50 (1000 π - 1.
1 × 1481) ] ≈ 2.
=3141 of π of × of =1000 of π of × of 95mH ≈ 3mHIM=IthI.
Had set in 6A type when shedding protective act, restrict IM=3141 of peak value of dc electric current.
6A, by afore-mentioned choices brake of 1000A commutate brilliant is in charge of and brake of 2000A inversion brilliant is in charge of cross voltaic ability computation, criterion peak value of dc electric current should achieve: =6283A of π of 2=6283A2000 of 1000 π × because this, press IM=3141.
6A computation decides Id=3mH is safe to rectification and canal of inversion brilliant brake. ⑧ commutate transformer leaks feeling commutate transformer side of a powerful person 2500/6=416 of every photograph capacity.
7kVA commutate transformer transformer of commutate of 660V/=381 V of phase voltage of side of a powerful person electric current of phasing of forehead of side of a powerful person 416.
Voltage of short circuit of transformer of commutate of 7 × 103/381=1094A 381 × 6.
5%=24.
Impedance of short circuit of 765V commutate transformer 24.
765/1094=0.
Transformer of 0226 Ω commutate every photograph leakage feels (resistor of oversight transformer winding) 0.
0226/ (2 π × 50) brake of brilliant of commutate of ⑨ of =72 μ H is in charge of ° of Sin60 of × of actual susceptive Di/dtdi/dt =660 / (2 × 72)=5.
6A/ μ S and rectification brilliant brake is in charge of can S of susceptive Di/dt=100A/ μ , the Di/dt that the leakage feeling enough of transformer of this proof commutate runs brilliant dam up water limits very safe rate. So, the current limliting inductance of 660V side is not installed in some transducer circuitry, also be reasonable. Brake of brilliant of Nextpage ⑩ inversion is in charge of ° of Sin30 of × of Ua of × of actual susceptive Di/dtdi/dt= / (1039 × of × of 2Lk) = Sin30 ° / (2 × 5)=73.
5A/ μ S expresses brake of brilliant of 3 homebred inversion to be in charge of Di/dt to restrict inductance reference to be worth frequency (H)5432 of μ of LK(of Hz)20040010002000400010000 limitation inductance.
521.
The alternative that brake of 5 brilliant of place choosing inversion provide transformer of Di/dt=200A/ μ S2, commutate 1, the transformer that the distinction of rectification transformer and electric power transformer uses for rectification device power supply, say for rectification transformer. Although rectification transformer and electric power transformer work the principle is same (induction of electromagnetism of farad younger brother is mensurable) , the structure is similar (two when be circled on collective core or two on above winding is comprised) , exterior close (it is a kind of dormant wiring) . But both still put in very big distinction: Transformer of ① electric power has 3 sine pulse only inside a cycle. The pulse inside a cycle counts rectification transformer (namely equivalent photograph is counted) can amount to 6 or 12. High low pressure of transformer of ② electric power matchs with photograph of grade of voltage of electrified wire netting normally, and rectification transformer is net side voltage and photograph of grade of voltage of electrified wire netting match and voltage of side of a powerful person can ask according to load only, rectification means and calm. ③ commutate transformer needs to undertake inverting impedance is calculated. The additional loss that ④ commutate transformer causes as a result of harmonic cannot be ignored. Accordingly, when the rectification transformer below condition of same power social estate is being made, the quantity that use copper and silicon steel piece dosage should be gotten high much. This shows, it is improper that v factory is in charge of the transformer of power supply of intermediate frequency transducer to be replaced with electric power transformer to brilliant brake. If carry brilliant dam up water,be in charge of intermediate frequency transducer only such load, must use rectification transformer. 2, rectification transformer capacity decides really: The classics customs examination of the capacity S of rectification transformer and the rated power P that transducer of intermediate frequency of brilliant brake canal outputs ties formula: S = ≈ 1.
25P (KVA) among them the product of the power factor of load of transformer of the efficiency that K is rectification transformer, commutate, assurance coefficient, take 0.
85 η 1: Brilliant brake provides the efficiency of commutator of intermediate frequency transducer, take 0.
97. η 2: Brilliant brake provides the efficiency of inverter of intermediate frequency transducer, take 0.
97. For example: Brilliant brake is in charge of the rated power of intermediate frequency transducer to be 2000kW, take the place of to go up type, the nominal capacity of rectification transformer is 2500kVA. The series of rectification transformer nominal capacity chart: GB1094.
The rating that 1-1996 sets should preferential from alignment of the R10 in GB321 (... 100, 125, 160, 200, 250, 315, 400, 600, 630, 800, 1000... ) in choose. 3, group of rectification transformer connection fastens ① group of connection of transformer of 6 pulse commutate does not have two kinds of forms: A kind: D, d0 another kind: D, group of connection of transformer of 12 pulse commutate fastens Yn11 ② to also have two kinds of forms: A kind of form is above group of two kinds of different connection is other carry acquires parallel connection of transformer of 6 pulse commutate all right equivalent transformer of 12 pulse commutate. Another kind of form, be one kind " 3 winding " transformer of 12 pulse commutate, its connection group fastens: D, paralell connection of transformer of 6 pulse commutate runs Do-yn112 station composition is equivalent the advantage of 12 pulse is to be able to ensure D, d0 and D, yn11 of two kinds of voltage change than be close to very much, precision of its voltage error can amount to ± 0.
2% . A kind of form after using (only station the 12 pulse mode of 3 winding) as a result of " Yn is received " with " D is received " v/LIT all over the ground number must differ times, and circle for integer, because this must use fixed v/LIT all over the ground number compare, wait like 3/5, 4/7, 7/12, 8/14, 11/19, 15/26, 18/31, 19/33, 22/38, 23/40, 26/45. After the v/LIT all over the ground number that uses these securing is compared, its error precision can amount to ± 1% . Rectification transformer size is smaller, v/LIT all over the ground number is more, its become smaller also than the error, best circumstance also can achieve ± 2% less than. Accordingly, v factory is when transformer of commutate of make choice of, unless transformer size is particularly large,ask to voltage error precision with transducer particularly tall, great majority circumstance should take odd stand the form of 12 pulse, because opposite at the first kind of form, after all it covers an area of the little, province that use material, loss low, efficiency is tall, and the technology is mature. The join group of transformer of 24 pulse commutate fastens ③ the rectification transformer of 24 pulse is comprised by transformer of commutate of 2 12 pulse. Two join means is: D, yn11-d0, among them a high pressure moves + 7.
5 ° , another high pressure moves - 7.
5 ° . 4, the impedance voltage K of rectification transformer.
The impedance voltage of the transformer of a few kinds of commutate with v commonly used factory, can consult choice issueing a list. Express voltage of 4 commonly used rectification transformer impedance to choose to express a capacity (KVA) 6301000160025004000630010000 impedance voltage (%)666.
56.
577.
57.
5 ～ 8nextpage 3, harmonic source and its harm to electric current of harmonic of infuse of public electrified wire netting nonlinear electric equipment says for harmonic source. The inductive heating installation that v factory uses, it is the gather of many harmonic source. The commutator of bridge-type of three-phase fully control in transducer of canal of ① brilliant brake intermediate frequency and inverter are harmonic source. Among them, the harmonic that arises by rectifier is the mainest to the influence of electrified wire netting. Itself of capacitor of ② electric power is not harmonic source, but when capacitor assembles brake, current infuse electrified wire netting can become source of transient sex harmonic, become especially when tuning of capacitor spur track is undeserved, can cause harmful harmonic resonance and harmonic enlarge appearance. Choice of parameter of ③ commutate transformer is undeserved, design construction and workmanship are undesirable, core material quality is poor, also can produce bigger harmonic and to infuse of electrified wire netting a large number of harmonic, become harmonic source. In all harmonic source, the harmonic electricity that the commutator in transducer of intermediate frequency of brilliant brake canal produces is main harmonic source. These harmonic report disgorge enter power supply system, voltage drop produces on power supply circuitry, harmonic voltage and base wave voltage alternate is added, cause communal join to nod (the joint that the user receives public electrified wire netting) voltage weaveform distortion. Additional, when the brilliant brake of transducer of brilliant brake canal intermediate frequency is in charge of commutation, gap produces on wave of voltage of sine of electrified wire netting, also accentuated voltage weaveform distortion. The harm that harmonic causes to electrified wire netting is many sided: ① counts H=3k-1 when harmonic to the influence of electric equipment second when, harmonic voltage heft is the heft that disobey order (2, 5, 8... ) , generation goes against foreword magnetic flux, make electromotor generation turns over torque, cause dynamo stator, rotor to produce additional loss and add temperature rise, rotor particularly serious, and influence dynamo output, guide the power factor to electromotor and the biggest torsion drop. The magnetizing current specified amount of transformer is extra big. Power loss increases the accuracy that affects appearance. (concerned data introduces: Voltage distortion leads more than 10% meetings to bring about electronic switch to produce misoperation, more than 5% meetings cause interconnected system of computer science department disorder. ) the harm that ② causes to electric power capacitor. Harmonic increases the partial discharge of capacitor medium and hot ageing, make its loss increases, make capacitor causes damage because of temperature rise thereby. Can produce harmonic enlarge sometimes, make capacitor attaint is accelerated. Still can cause mechanical vibration. ③ causes bad influence ④ to cause undesirable effect to losing distribution line to accusing system and protection oneself. 4, the inhibition that harmonic affects measure: 1, increase short circuit comparing. Short circuit comparing is the ratio that points to capacity of short circuit of electrified wire netting and transducer rated power. If did not adopt harmonic to restrain measure, to assure electric energy quality, must try to restrict to transducer rated power, increase short circuit comparing namely. Graph the relation of the rectification unit that door place recommends the relation England Electricity Department of the power of 2 commutate device and capacity of short circuit of electrified wire netting and rectification photograph number and capacity of short circuit of electrified wire netting and rectification photograph number (refer to a graph 2) , can draw lessons from for us. 2, the net side that raises rectification transformer respectively and grade of voltage of side of a powerful person, strengthen a system to bear the ability of harmonic. 3, the phase shift that uses rectification transformer and raise rectification photograph number to restrain harmonic to be in usually, the H of diagnostic harmonic frequency that the electric current of source of this kind of harmonic contains rectifier and rectification photograph number are in theoretic have the following concern: H=kP ± 1P -- rectifier photograph number, p=3, 6, 12, 24... K -- random integral, k=1, 2, 3, 4... when P=3, h=2, 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19, 20, 22, 23, 25... when P=6, h=5, 7, 11, 13, 17, 19, 23, 25, 29, 31... when P=12, h=11, 13, 23, 25, 35, 37... when P=24, h=23, 25, 47, 49... this shows, increasing rectification photograph to count this one measure is very effective to reducing harmonic electric current. And increase rectification photograph number, the tie line kind that carries change commutate transformer namely and change move the combination of photograph winding will come true. Nextpage with transformer of commutate of transducer of 2000kW intermediate frequency, 12 pulse. Voltage of side of 660V50Hz a powerful person is exemple make harmonic analysis. 11, 13, 23, 25 times harmonic electric current sees next tables: The convert when brake of brilliant of watch 5 2000kW660V50Hz is in charge of intermediate frequency transducer to move arrives Fang Jungen of electric current of 10kV side harmonic is worth computation to express (12 pulse) harmonic coefficient (Kh)Id ＇ I11I13I23I250.
14070.
11670.
06650.
Ih (A)116410 of 0622 harmonic electric current.
89.
05.
14.
8Ih -- Ih =Id of electric current of H second harmonic × of ＇ × Kh 0.
066Idq -- it is a group of Y (or △ ) the dc of 6 pulse commutate spreads a cost. Id ＇ -- it is a group of Y (or △ ) of 6 pulse commutate base wave Fang Jungen is worth. Kh -- harmonic coefficient, reach in computation and emulation spectrum graph. 0.
066 -- rectification transformer changes than, 37 660V/10kV35, harmonic can be ignorred. National level GB/T14549-93 " electric energy quality is public harmonic of electrified wire netting " try to the harmonic of the infuse in electrified wire netting standard. In this standard " the harmonic electricity that communal join burns infuse allows a value " the regulation is when voltage of standard of 100MVA of capacity of fiducial short circuit, 10kV, harmonic electric current (Fang Jungen is worth) the numerical value that should not leave a table more than: Express the harmonic electricity that communal join burns 6 infuse to allow to be worth standard voltage (KV) capacity of fiducial short circuit (MVA) harmonic frequency and harmonic electric current allow a value 11132325101009.
37.
94.
54.
1 pick from GB/T14549-93 " electric energy quality is public harmonic of electrified wire netting " the capacity of the smallest short circuit that when electrified wire netting communal join nods is different from on when expressing capacity of fiducial short circuit, can press type is amended on the harmonic electric current of the watch allows a value.
In type: Sk1 -- the capacity of the smallest short circuit that communal join nods, MVASk2 -- capacity of fiducial short circuit, MVAI Hp -- on second harmonic electric current allows the H in the watch value, AI H -- second harmonic electric current allows the H when short circuit capacity is Sk1 value, a expresses 7 communal join to nod 11132325Sk1 of frequency of harmonic of capacity of the smallest short circuit (MVA) 116114113117 by on the watch is visible, the size of the smallest short circuit that wants communal join place only is not less than 117MVA, 2000kW660V takes a line value of electric current of harmonic of 12 pulsatile commutate already was close to relevant specification. But GB returns a regulation, with every user of in succession contact, allocate of the consultative capacity that allows a value to be in by this user this a little bit to the harmonic electric current of infuse of electrified wire netting and the capacity of power supply equipment that communal join nods than undertaking, such, although approachable standard capacity but it is very difficult to amount to mark actually. Anyhow, raising rectification photograph to count is the significant step that reduces harmonic electric current, transducer of general high-power intermediate frequency often needs much stage parallel connection, accordingly, it is under 12 pulse (contain 12 pulse) won't increase investment commonly. When pulse number exceeds 12, want to consider the impact that brings to investment and maintenance, should control use. 36 pulse above already did not have apparent effect to reducing harmonic, do not recommend use. 4, low-pressure side adds outfit passive communication filter wave and without merit compensation device this unit is main be combined by controller of reactor of wave of capacitor, filter, microcomputer, contactor, breaker and become, with harmonic source paralell connection. In the basis in be being applied actually size of component of harmonic electric current and undertake be designinged technically without work demand situation, this device offers channel of a low impedance to harmonic source, harmonic electric current flows into filter for the most part (filter wave effect can amount to 90% above) , make distortion of electrified wire netting is reduced, and to base wave frequency (50Hz) filter wave device can be offerred to electrified wire netting without result power, in order to raise power factor, achieve without merit compensation effect. Outfit passive communication is added in low-pressure side filter wave and without merit compensation device, investment is small (the 1/3 that is high-pressured side, the 1/20 that is active filter) , the effect is good, because of as shunt-wound as harmonic source, can on the spot absorbs a large number of harmonic, make the loss of the system that use phone of whole user is reduced, interference eliminates. Accordingly, it is the better program that settles harmonic to exceed bid currently. CNC Milling