Različitost rješenja svjetskih energetskih sistema i regulacije napon na njma vrlo često zahtijeva od proizvođača transformatora neuobičajene i specifične konstrukcije. Glavnina uzroka in problema je vezana upravo za regulaciju napona. Na koji način, u zadanim uslovima, ostvariti regulaciju biti če zavisno od širokog spektra činilaca.
Sa sličnim problemom smo se susreli i mi u našoj tvornici. Način na koji smo jedan takav problem rješili biti če izložen u ovom članku.
Svi dijagrami i slike su nacrtane na primjeru regulacijskog transformatora
RТ 25 МVА - 11о/13,8 kV +- 9 х 1,25 % Dyn 1.
Pored toga, sistem је uopsten i opisan jednostavnim matematičkim formulacijama
koje se mogu primjeniti za bilo koji drugi slican slucaj regulacije.
EKSPERIMENTALNI REZULTATI MJERENJA ODZIVA NAMOTAJA TRANSFORMATORA PRI OSCILAT...Juso Ikanovic
U ovom radu ukratko је dat koncept konзtruktivnog rjesenja autotransformatora
tip ART бо/2о/4о MVA 22о/132 +- 8х1,25% / ЗЗ +- 8х1,25% kV proizvodnje
Energoinvest - Cгnuce. U toku pгoizvodnje i na zavrsenim transformatorima
izvгseno је niz mjeгenja, а роsеbnа paznja posvecena је гaspodjeli napona ро
namotajima tгansfoгmatora. Ovdje su dati neki od rezultata mjerenja pri oscilatornom
i apeгiodicnom niskonaponskom pobudivanju na izvodima transformatora.
Problems in Design and Construction of High Power Transformers for Electric А...Juso Ikanovic
With the focus оп eddy current caused losses this article treats
some of the problems arising in the field of transformer
construction for electric аrc melting furnaces.
EKSPERIMENTALNI REZULTATI MJERENJA ODZIVA NAMOTAJA TRANSFORMATORA PRI OSCILAT...Juso Ikanovic
U ovom radu ukratko је dat koncept konзtruktivnog rjesenja autotransformatora
tip ART бо/2о/4о MVA 22о/132 +- 8х1,25% / ЗЗ +- 8х1,25% kV proizvodnje
Energoinvest - Cгnuce. U toku pгoizvodnje i na zavrsenim transformatorima
izvгseno је niz mjeгenja, а роsеbnа paznja posvecena је гaspodjeli napona ро
namotajima tгansfoгmatora. Ovdje su dati neki od rezultata mjerenja pri oscilatornom
i apeгiodicnom niskonaponskom pobudivanju na izvodima transformatora.
Problems in Design and Construction of High Power Transformers for Electric А...Juso Ikanovic
With the focus оп eddy current caused losses this article treats
some of the problems arising in the field of transformer
construction for electric аrc melting furnaces.
DVOHODNO VIJACNO NAVITJE S PRAVOKOTNO ZICO Z UCINKI TRANSPONIRANEGA VODNIKAJuso Ikanovic
Predlozeni izum se nanasa na izdelavo dvohodnega vijacnega navitja s pravokotno zico z ucinki transponiranega vodnika.
Tukaj prikazana navijalna tehnika omogoca, da na obicajnem horizontalnem navijalnem stroju izdelamo dvohodno vijacno navitje in transponiran vodnik hkrati, s transpozicijami enakomerno razporejenimi po dejanskem stevilu ovo-
jev v navitju. Izum sodi v podrocje visoko tokovne tehnike in se lahko uporabi na podrocju izdelave nizkonapetostnih, visoko tokovnih navitij mocnostnih transformatorjev.
Dvojni sucni disk med navijalnim strojem in odvijalcem omogoca kontinuirano navijanje navitja brez vmesnih prekinitev zic in nepotrebnih lotov v navitju (slika 1).
Dvohodno vijacno navitje z ucinki transponiranega vodnika odpravlja tehnoloske omejitve znane v tehniki izdelave transponiranega vodnika NTCTC;
omogoca tvorbo ucinkovitejsih hladilnih kanalov v navitju, faktorju transpozicije ne postavlja strogih omejitev, prehodi zic med hodoma so lahko dodatno zavarovani, navitje ne potrebuje montaznega opleta iz poliestra.
Dvohodno vijacno navitje s pravokotno zico izdelano z opisano navijalno tehniko ima boljsi prostorski izkoristek in posledicno boljsi polnilni faktor navitja.
Transformers for Electric Arc-Melting Furnaces with Direct Voltage RegulationJuso Ikanovic
In modern metallurgical and chemical industry there is an
increasing need for electric arc-melting furnaces. Transformer
is also one of the vital parts by which power is supplied to furnaces.
Because of their technological aspects, Electric arcmelting
furnaces, need special transformers different from
usual distribution units. The main problem arises from the demand
for relatively wide range of regulation on the low voltage
side.
In this article one of the many principles of voltage
regulation is described, nomely, low voltage regulation by
means of magnetic flux variations.
In the article an equivalent T-circuit of power transformer
regulation is analyzed and graphically shown. The regulation
of the secondary voltage is presented in the connection with
an auxiliary unit in a secondary circuit. For an idealizational
figure of a power transformer, equations are written on a general
model describing the magnetic coupling between the
windings and the electric connections of both units. In the further
discussion stray reactances of a constant value and the regulation
of voltage as a disturbance and a single variable in a
system are progressively brought in. The transformation of the
general model into a classic form of the equivalent T-circuit
can facilitate the designer' s research of the influence of the regulation
on a system and basic parameters of a transformer.
The practical benefit of the scheme is shown on an example
where the short-circuit voltage over the total impedance of the
system is determined.
Improvement of the Filling Factor in Windings of Power TransformersJuso Ikanovic
The paper describes an improvement in the filling factor of the double helical winding. Namely, the designers generally use a double helical winding for the middle and up to the highest rated power transformers. By means of a well approched study in dielectric and thermal states of the winding, the optimal minimum of the required insulation is achieved contributing to an important improvement of the filling factor indeed. The concept of power and loss density in the volume of the winding was taken for the criteria of energy loading in the space. In its second part, the paper describess, one concrete example of a transformer of rated power 50MVA-77/10,5kV, a comparative calculation of the filling factor, power density and losses for three different conductor`s insulation thickness increases. At the end of the calculation, the improved filling factor`s effect on the copper mass, mass of the magnetic steel and total mass of the transformer is shown.
Key words: Power Transformer, Filling Factor, Winding, Power Density, Designer.
Converter Transformers manufactured to the Slovenian RailwaysJuso Ikanovic
The paper contains an overview of the most significant
technical characteristics of converter transformers
manufactured to modernize of Slovenian Railways. The main
features and characteristics of this type of the traction drives
with various intersected winding configurations are described.
The referenced projects include the first application of axial
winding crossing, i.e. a technological innovation resolving the
strong magnetic coupling requirement of low-voltage
windings. The solution is referred to as an intersected winding.
With one, two and three winding crossings coupling factors of
0.920 and 0.967 are achieved. The results meet the
specifications, of the SIST EN standard.
POWER TRANSFORMER WINDINGS WITHOUT PAPER INSULATIONJuso Ikanovic
The paper gives a presentation of some most important properties of the enamel insulated rectangular wire windings. The basic paper insulation in the winding conductors is replaced completely by PVA (polyvinyl acetal) of thermal class E (120˚C). Single and double threaded helical windings are considered. The main properties and benefits from the perspective of dielectric, thermal and dynamic strength of the winding are noted.
Verification of dielectric strength and measurements of breakdown voltages of the insulation arrangement of oil and enamel. We conducted tests on models that represent section of real windings. The resulting values of breakdown voltages are considered when designing windings in transformers with enamel insulated wires.
Key words: Power Transformer – Winding – Enamel Insulation – Dielectric strength
REPARATION OF POWER TRANSFORMERS 150 MVA- 220 kVJuso Ikanovic
The article describes the repair of two power transformers ra ted 150 MVA that had been und er at RTP Divača and RTP
Beričevo Power Substations. The repair was executed at ETRA 33 Energetski transformatorji d. d. in the years 1993 and 1999. The
scope of repair: The electrical part, i.e. all windings, insulation, connections, was made completely new. The active [Xlrt was.filled with new
oil.
The short description (i the damages, description of the repair and the results of the test~ conce ming the transjormer se1vice characteristics
are presented in the article.
Močnostni transformatorji za prenovo Dravskih hidroelektrarnJuso Ikanovic
V članku je podan pregled nekaterih
pomembnejših tehničnih karakteristik energetskih
transformatorjev vgrajenih v verigo Dravskih elektrarn:
HE Mariborski otok, HE Dravograd, HE Vuzenica, HE
Ožbalt in HE Vuhred. Opisane so glavne konstrukcijske
značilnosti navitij, magnetnih krogov in hladilnih
aparatov ter nekatere tehnološke novosti na področju
projektiranja, konstrukcije in izdelave navitij. Opis
transformatorjev je razdeljen na tri dele in sicer:
električni tokokrog, v katerem so opisana navitja,
magnetni krog, s karakteristikami magnetnega jedra ter
hladilni krog, kjer so opisane posamezne vrste hlajenja.
In the paper basic properties of insulation system made from materials of different thermal grades are dealt
with. Wide spread paper insulation is replaced by insulation consisting of inorganic materials of higher thermal grade.
All other solid materials in contact with the winding are of thermal grade A. Active part of the transformer is immersed in
conventional mineral oil. The benefits of improved built-in materials are described and allowed thermal limitations
according to IEC TS 60076-14 are stated. New possibilities and obstacles with using semi-hybrid insulation system are
also given.
Power Transformer Windings without Paper Insulation Juso Ikanovic
The paper gives a presentation of some most important properties of the enamel insulated rectangular wire windings. The basic paper insulation in the winding conductors is replaced completely by PVA (polyvinyl acetal) of thermal class E (120˚C). Single- and double threaded helical windings are dealt with. The active part of the transformer is immersed in mineral oil of thermal class A. The main properties and benefits from the perspective of dielectric, thermal and dynamic strength of the winding are noted. According to the hot-spot criteria, the relative ageing rate of the enamel insulation is noted. Measurements of the withstand voltage of the enamel insulation, taken according to our own procedure in our high-voltage laboratory, are noted comparatively to the IEC standard. In conclusion, an overview of the quantity of windings between 2001 and 2012 is given, together with an estimate of the influence of input costs. With regard to our up-to-date production and experience, an evaluation of the further use of windings without paper insulation is given.
Key words: Power Transformer, Helical Winding, Enamel Insulation, Withstand Voltage
CONVERTER TRANSFORMERS FOR REFURBISHMENT OF SLOVENIAN RAILWAYSJuso Ikanovic
The paper contains an overview of the most significant technical characteristics of converter transformers manufactured for modernization of Slovenian railways between years 1993 and 2014. Transformers are in service in the following power stations: Sava, Črnotiče, Divača, Dekani, and will be soon installed into all major stations on the Pragersko- Hodoš railway line. The main features and characteristics of this type of traction drives are described; the coupling factor as a geometric property of low voltage windings with different numbers of mutual axial crossings, the thermal loading as a consequence of cyclic overload and protection of the converter from transferred overvoltages from the network. The referenced projects include the first application of axial winding crossing, a technical innovation resolving the strict magnetic coupling requirement of low voltage windings. On the basis of the results of the type heat run test, a thermal profile was made corresponding to class VI overloading cycle. Between the high and low voltage windings an earthed screen was incorporated and the efficiency of the shielding with and without earthed was tested. The results were compared with the requirements of the SIST EN standards.
Keywords: Converter Transformer, Coupling factor, Aaxial winding crossing, Eearthed screen, Thermal profile
IMPACT OF OPTICAL FIBRE TEMPERATURE SENSORS ON DIELECTRIC WITHSTAND OF OIL CH...Juso Ikanovic
Paper analyses the impact of fiber- optic temperature sensors installation on dielectric withstand of oil-filled paperless transformer winding insulation. A PVA enamel insulated helical winding models with 3 mm oil channel were built according to technological process of Kolektor Etra and tested in EIMV high-voltage laboratory. AC 50Hz breakdown voltage and partial discharge levels of the winding models with and without optical fibre temperature sensor were measured as well as dissolved gas analyses of the oil samples were made. Experimental results were evaluated and analysed through dielectric study based on finite elements simulation and empirical design guidelines based on partial discharge inception models. Based on these results, paper discusses installation of the fiber-optic temperature sensors in the sandwich construction.
Keywords:Fiber-optic temperature sensor, Dielectric withstand, PVA helical winding, Power Transformer
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DVOHODNO VIJACNO NAVITJE S PRAVOKOTNO ZICO Z UCINKI TRANSPONIRANEGA VODNIKAJuso Ikanovic
Predlozeni izum se nanasa na izdelavo dvohodnega vijacnega navitja s pravokotno zico z ucinki transponiranega vodnika.
Tukaj prikazana navijalna tehnika omogoca, da na obicajnem horizontalnem navijalnem stroju izdelamo dvohodno vijacno navitje in transponiran vodnik hkrati, s transpozicijami enakomerno razporejenimi po dejanskem stevilu ovo-
jev v navitju. Izum sodi v podrocje visoko tokovne tehnike in se lahko uporabi na podrocju izdelave nizkonapetostnih, visoko tokovnih navitij mocnostnih transformatorjev.
Dvojni sucni disk med navijalnim strojem in odvijalcem omogoca kontinuirano navijanje navitja brez vmesnih prekinitev zic in nepotrebnih lotov v navitju (slika 1).
Dvohodno vijacno navitje z ucinki transponiranega vodnika odpravlja tehnoloske omejitve znane v tehniki izdelave transponiranega vodnika NTCTC;
omogoca tvorbo ucinkovitejsih hladilnih kanalov v navitju, faktorju transpozicije ne postavlja strogih omejitev, prehodi zic med hodoma so lahko dodatno zavarovani, navitje ne potrebuje montaznega opleta iz poliestra.
Dvohodno vijacno navitje s pravokotno zico izdelano z opisano navijalno tehniko ima boljsi prostorski izkoristek in posledicno boljsi polnilni faktor navitja.
Transformers for Electric Arc-Melting Furnaces with Direct Voltage RegulationJuso Ikanovic
In modern metallurgical and chemical industry there is an
increasing need for electric arc-melting furnaces. Transformer
is also one of the vital parts by which power is supplied to furnaces.
Because of their technological aspects, Electric arcmelting
furnaces, need special transformers different from
usual distribution units. The main problem arises from the demand
for relatively wide range of regulation on the low voltage
side.
In this article one of the many principles of voltage
regulation is described, nomely, low voltage regulation by
means of magnetic flux variations.
In the article an equivalent T-circuit of power transformer
regulation is analyzed and graphically shown. The regulation
of the secondary voltage is presented in the connection with
an auxiliary unit in a secondary circuit. For an idealizational
figure of a power transformer, equations are written on a general
model describing the magnetic coupling between the
windings and the electric connections of both units. In the further
discussion stray reactances of a constant value and the regulation
of voltage as a disturbance and a single variable in a
system are progressively brought in. The transformation of the
general model into a classic form of the equivalent T-circuit
can facilitate the designer' s research of the influence of the regulation
on a system and basic parameters of a transformer.
The practical benefit of the scheme is shown on an example
where the short-circuit voltage over the total impedance of the
system is determined.
Improvement of the Filling Factor in Windings of Power TransformersJuso Ikanovic
The paper describes an improvement in the filling factor of the double helical winding. Namely, the designers generally use a double helical winding for the middle and up to the highest rated power transformers. By means of a well approched study in dielectric and thermal states of the winding, the optimal minimum of the required insulation is achieved contributing to an important improvement of the filling factor indeed. The concept of power and loss density in the volume of the winding was taken for the criteria of energy loading in the space. In its second part, the paper describess, one concrete example of a transformer of rated power 50MVA-77/10,5kV, a comparative calculation of the filling factor, power density and losses for three different conductor`s insulation thickness increases. At the end of the calculation, the improved filling factor`s effect on the copper mass, mass of the magnetic steel and total mass of the transformer is shown.
Key words: Power Transformer, Filling Factor, Winding, Power Density, Designer.
Converter Transformers manufactured to the Slovenian RailwaysJuso Ikanovic
The paper contains an overview of the most significant
technical characteristics of converter transformers
manufactured to modernize of Slovenian Railways. The main
features and characteristics of this type of the traction drives
with various intersected winding configurations are described.
The referenced projects include the first application of axial
winding crossing, i.e. a technological innovation resolving the
strong magnetic coupling requirement of low-voltage
windings. The solution is referred to as an intersected winding.
With one, two and three winding crossings coupling factors of
0.920 and 0.967 are achieved. The results meet the
specifications, of the SIST EN standard.
POWER TRANSFORMER WINDINGS WITHOUT PAPER INSULATIONJuso Ikanovic
The paper gives a presentation of some most important properties of the enamel insulated rectangular wire windings. The basic paper insulation in the winding conductors is replaced completely by PVA (polyvinyl acetal) of thermal class E (120˚C). Single and double threaded helical windings are considered. The main properties and benefits from the perspective of dielectric, thermal and dynamic strength of the winding are noted.
Verification of dielectric strength and measurements of breakdown voltages of the insulation arrangement of oil and enamel. We conducted tests on models that represent section of real windings. The resulting values of breakdown voltages are considered when designing windings in transformers with enamel insulated wires.
Key words: Power Transformer – Winding – Enamel Insulation – Dielectric strength
REPARATION OF POWER TRANSFORMERS 150 MVA- 220 kVJuso Ikanovic
The article describes the repair of two power transformers ra ted 150 MVA that had been und er at RTP Divača and RTP
Beričevo Power Substations. The repair was executed at ETRA 33 Energetski transformatorji d. d. in the years 1993 and 1999. The
scope of repair: The electrical part, i.e. all windings, insulation, connections, was made completely new. The active [Xlrt was.filled with new
oil.
The short description (i the damages, description of the repair and the results of the test~ conce ming the transjormer se1vice characteristics
are presented in the article.
Močnostni transformatorji za prenovo Dravskih hidroelektrarnJuso Ikanovic
V članku je podan pregled nekaterih
pomembnejših tehničnih karakteristik energetskih
transformatorjev vgrajenih v verigo Dravskih elektrarn:
HE Mariborski otok, HE Dravograd, HE Vuzenica, HE
Ožbalt in HE Vuhred. Opisane so glavne konstrukcijske
značilnosti navitij, magnetnih krogov in hladilnih
aparatov ter nekatere tehnološke novosti na področju
projektiranja, konstrukcije in izdelave navitij. Opis
transformatorjev je razdeljen na tri dele in sicer:
električni tokokrog, v katerem so opisana navitja,
magnetni krog, s karakteristikami magnetnega jedra ter
hladilni krog, kjer so opisane posamezne vrste hlajenja.
In the paper basic properties of insulation system made from materials of different thermal grades are dealt
with. Wide spread paper insulation is replaced by insulation consisting of inorganic materials of higher thermal grade.
All other solid materials in contact with the winding are of thermal grade A. Active part of the transformer is immersed in
conventional mineral oil. The benefits of improved built-in materials are described and allowed thermal limitations
according to IEC TS 60076-14 are stated. New possibilities and obstacles with using semi-hybrid insulation system are
also given.
Power Transformer Windings without Paper Insulation Juso Ikanovic
The paper gives a presentation of some most important properties of the enamel insulated rectangular wire windings. The basic paper insulation in the winding conductors is replaced completely by PVA (polyvinyl acetal) of thermal class E (120˚C). Single- and double threaded helical windings are dealt with. The active part of the transformer is immersed in mineral oil of thermal class A. The main properties and benefits from the perspective of dielectric, thermal and dynamic strength of the winding are noted. According to the hot-spot criteria, the relative ageing rate of the enamel insulation is noted. Measurements of the withstand voltage of the enamel insulation, taken according to our own procedure in our high-voltage laboratory, are noted comparatively to the IEC standard. In conclusion, an overview of the quantity of windings between 2001 and 2012 is given, together with an estimate of the influence of input costs. With regard to our up-to-date production and experience, an evaluation of the further use of windings without paper insulation is given.
Key words: Power Transformer, Helical Winding, Enamel Insulation, Withstand Voltage
CONVERTER TRANSFORMERS FOR REFURBISHMENT OF SLOVENIAN RAILWAYSJuso Ikanovic
The paper contains an overview of the most significant technical characteristics of converter transformers manufactured for modernization of Slovenian railways between years 1993 and 2014. Transformers are in service in the following power stations: Sava, Črnotiče, Divača, Dekani, and will be soon installed into all major stations on the Pragersko- Hodoš railway line. The main features and characteristics of this type of traction drives are described; the coupling factor as a geometric property of low voltage windings with different numbers of mutual axial crossings, the thermal loading as a consequence of cyclic overload and protection of the converter from transferred overvoltages from the network. The referenced projects include the first application of axial winding crossing, a technical innovation resolving the strict magnetic coupling requirement of low voltage windings. On the basis of the results of the type heat run test, a thermal profile was made corresponding to class VI overloading cycle. Between the high and low voltage windings an earthed screen was incorporated and the efficiency of the shielding with and without earthed was tested. The results were compared with the requirements of the SIST EN standards.
Keywords: Converter Transformer, Coupling factor, Aaxial winding crossing, Eearthed screen, Thermal profile
IMPACT OF OPTICAL FIBRE TEMPERATURE SENSORS ON DIELECTRIC WITHSTAND OF OIL CH...Juso Ikanovic
Paper analyses the impact of fiber- optic temperature sensors installation on dielectric withstand of oil-filled paperless transformer winding insulation. A PVA enamel insulated helical winding models with 3 mm oil channel were built according to technological process of Kolektor Etra and tested in EIMV high-voltage laboratory. AC 50Hz breakdown voltage and partial discharge levels of the winding models with and without optical fibre temperature sensor were measured as well as dissolved gas analyses of the oil samples were made. Experimental results were evaluated and analysed through dielectric study based on finite elements simulation and empirical design guidelines based on partial discharge inception models. Based on these results, paper discusses installation of the fiber-optic temperature sensors in the sandwich construction.
Keywords:Fiber-optic temperature sensor, Dielectric withstand, PVA helical winding, Power Transformer
IMPACT OF OPTICAL FIBRE TEMPERATURE SENSORS ON DIELECTRIC WITHSTAND OF OIL CH...
BOOSTER REGULACIJA NAPONA NA NISKONAPONSKOJ SТRANI ENERGEТSКIН TRANSFORМATORA
1. JUGOSLAVENSKI КОМПЕТ MEDUNARODNE KONFERENCIJE ZA VELIKE ELEKTRICNE MREZE - CIGRE
Z А G R Е В. ВerislaviCeva 6
XVII SЛVJEТOVANJE ELEKTROENERGEТICARA JUGOSLAVIJE
STR UGA. od 12.do 15.maja. 1985.
Juso Ikanovic, dip1.ing.
• ENERGOINVEST •
Тvornica trans!orиatora
LJUBLJANJ.
Referat broj 12.06
BOOSTER REGULJ.CIJJ. .liAPO.IiJ. lii.A. NISKO.IiAPONSKOJ SТIШП
ENERGEТSКIН TRJ.NSJORМJ.TORA
SJ.DRZAJ
Raz1i~itost rjeAenja svjetskih energetskih sistema i regu1acije napona na nji-
ma vr1o ~esto zahtijeva od proizvodaca trans!ormatora neuobicajene i speci!icne
konвtrukcije. G1avnina uzroka i proЬlema је vezana upravo za regu1aciju napona.
На koji nacin, u zadanim us1ovima, ostvariti regu1aciju biti се zavisno od si-
rokog spektra cini1aca.
Sa в1icnim proЬle•o• s•o se susre1i i Di u naAoj tvornici. Nacin na koji sшо
jedan takav рrоЬlеш rjesi1i Ьiti се iz1ozen u оvош c1anku.
Svi dijagraai i s1ike su nacrtane na primjeru regu1acijskog trans!orшatora
RТ 25 МVА - 11о/13,8 kV ~ 9 х 1,25 %Dyn 1.
Pored toga, sist~ш је uopsten i opisan jednostavni• шate•atickim !orшu1acijaaa
koje se шogu priшjeniti za Ьi1о koji drugi s1ican s1ucaj regu1acije.
45
2. R 12.06
1. UVOD
Uopsteno ве moze reci da је regu1acija napona ва вtanoviвta proizvo~aca jedan
od tezisnih konвtrukcijвko-tehno1oskih рrоЬlеша koji raвtom вnage i оЬiма re-
gu1acije poвtaju вvе в1ozeniji. Neke energetвke шreze u вvijetu i kod nав po-
nekad zahtijevaju od transforмatora шogucnoвt regu1acije napona na niskonapon-
вkoj вtrani. Teskoce u tom в1ucaju poвtaju јов koшp1ekвnije i sire.
U princ1pu је, za oвtvarenje takve. regu1ac1je, moguce regu1acijвk1 prekidac
(uoЬicajena је regu1acija napona pod opterecenjeш) namjeвtit1 na v1вokonapon
вkoj 111 niskonaponвkoj вtrani. Za koje rjesenje се ве konвtruktor od1uc1ti
zavis1t се od anogo cin11aca.
2. MOGUCiiOSTI REGUЫ.CIJE
2.1. Regu1ac1ja napona sa regu1ac1jвkiм prekidacem na viвokonaponвkoj вtrani
11i tzv. regu1ac1ja napona promen1j1vim magnetniм po1jem. Ova izvedba је
pr1hvat1j1va вашо u granicaшa niz1h napona, jer је vec kod вrednjih na-
pona tesko 1zvod1jiva. !ko ве radi jos о вројu trokut na visokonaponвkoj
вtrani za napone vise od 11о kV prakticno ne do1azi u obz1r. S1aboвt
ovakvog nacina regu1ac1je ве og1eda i u tome da ne moze obezЬijediti
вtalnost oвnovnih parametara (napon kratkog spoja, 1ndukcija u jezgru)
sto је u vecini в1ucajeva nepoze1jno .
2.2. Druga mogucnoвt је regu1acija napona sa regu1acijskim prekidacem na nis-
konaponвkoj strani. U princ1pu, treba teziti za tiм da је regu1ac1jвki
prekidac ugra~en na вtrani promjene napona, sto opet n1je izvodljivo kod
svih konstrukcija. Me~tim, porastoш snage uz re1at1vno niske sekundarne
napone, raste i вtгUја koju u tош s1ucaju treba prek1dati. Uв1jed toga
46
ве ra~aju novi proЬlemi koji ва воЬоm, u krajnjem s1ucaju, donose ne~a
cionalno projektirane jedinice 1 ugra~ene vr1o вkupe regu1ac1jske preki-
dace. U sveмu tome, prvenstven zadatak konвtruktora је da potr&Zi opti-
malnu varijantu koja се, za odre~en primjer, zahtijevati najmanje ugra-
~enog materijala na jed1n1cu вnage. Ро zakoniмa rasta вnage i 1inearnih
diмenz1ja na odnoв ugra~enih akt1vnih mater1ja1a је moguce uticati izbo- .
rom raz11citih napona navoja. Za uoЬicajene konвtrukcije, one sa re1ativ-
no ugodnim prenoвnia odnoвom, napon navoja је moguce izabrati u sirokom
raвponu. Transforмatori kod kojih se regu1acija vrsi na niskonaponвkoj
strani iaaju takve mogucnosti ogranicene ра је vec kod srednjih snaga,
uz npr. spoj zv1jezda na niskonaponвkoj strani, potrebno pr1bjegavati no-
vim rjesenjima. Cest је s1ucaj da је takvu regu1ac1ju potrebno ostvariti
ва dva 111 cak jednim navojem ро jednom regu1acijskom stepenu. Uz pratece
tehno1oske proЬleme, kao krajnji rezu1tat tako skrcen1h mogucnosti jav-
1jaju ве disproporcije u rastu 1inearnih dimenzija, koje ug1avnom i us1o-
v1javaju iznalazenje novih puteva i rjesenja.
3. R 12.06
2.3. Jedno tako rjeAenje је i regu1acija вekundarnog napona ва dodatnim tranв
!oraatoroa u вekundarnoш krugu в1. 1 (eng1. booвter tranв!orшer) о kојеш
се biti rijeci u ovoa c1anku.
А
г_-
1 ~
1
1
~
1
1
1
1
1
1 1 2 зL ________j
81. 1 Principje1na Аеша regu1acije (jedno!azni врој) -
А - g1avni tranв!orшator
1 - Viвokonaponвki namotaj
2 - Niвkonaponвki namotaj
3 - Tercijarni - regu1ac. namotaj
В - dodatni (booвter) tranв!ormator
4 - Uzbudni namotaj
5 - Serijвki namotaj
U principu ве regulacija oвtvaruje preko jednog tercijarnog - regu1a-
cijвkog namotaja 3 koji napaja uzbudni namotaj 4 dodatnog tranв!orшa
tora В.
Napon, odnoвno broj navoja, na tercijarnom-regu1acijвkom namotaju је ваdа
шoguce izabrati proizvo1jno i u sirokom raвponu. Kod vec odredene вnage
tog namotaja treba te!iti za tim da izaberemo onaj napon i вtruju koji се
naa dati najjednoвtavniji regu1acijвki prekidac. OЬicno вu to prekidaci
najnizeg naponвkog i вtrujnog nivoa (npr. 3о kV, 2оо А), вmjesteni u za-
jednickoa zvjezdiAtu tercijarnog-regulacijвkog namotaja i uzbudnog namo-
taja dodatnog tranв!orшatora. Sa вtanovista pogonвke вigurnoвti, вtatiв
ticno g1edano, regu1acijвki prekidac predвtav1ja najoвjet1jiviju tacku
svakog regulacijskog tranв!ormatora. Porastom napona i вtruje koju је
potrebno prekidati povecava ве i broj iвpada tranв!orшatora uzrokovanih
kvarovima na regu1acijвkom prekidacu. Zbog toga је razum1jiva te!nja za
cim vecim pojednoвtav1janjem tako va!nog dije1a вvakog regu1acijвkog
вiвtema.
47
4. R 12.06
3. РIЮ!'ЫЕП OS!IOVIПB P.1IШ'IEТ!li
Pretpostaviao da ze1iao regu1irati sekundarni napon od napona u2мin do u2maks
kod .odrzane snage ро dijagraиu na s1. 2.
0,4
P=Pn
1 =l1n
12 =l2nU2n/U2
u2
0,0-t--------+--------+----
~min U2n U2maks
81. 2
Xad se radi о regu1aciji napona na niskonaponskoj strani, mo!e se reci, da su
to k1asi~ni zahtjevi u tom pog1edu.
Xonstruktora trans!orzatora vr1o ~esto interesuje kako се se mijenjati osnovni
paraaetri ро obiau regu1acije, to su:
3.1. GuЬici u bakru i ze1jezu
3.2. Napon kratkog spoja i
3.3. Tipna snaga i cijena sistema
3.1. GuЬici u bakru i ze1jezu
Radi komp1eksnosti cje1okupnog sistema mijenjace se i guЬici ро cije1om obimu
regu1acije. Iz ~ih raz1oga su ukupni guЬici u bakru i ze1jezu ras~1anjeni na
svaki naaotaj i svaki trans!orшator Ato omogucava 1aksi uvid u stanje na sva-
kom stepenu sekundarnog napona.
U smis1u pojednostav1jenja ukupne proЬlematike pretpostavimo, da su guЬici u
bakru namotaja 1 i 2 te 4 i 5 g1avnog i dodatnog trans!ormatora jednaki. Na
ta~nost prakti~nih rezu1tata ovakva zanemarenja nemaju ve1ikog uticaja.
рcu1 8 рcu2maks pcu4 8 pcu5
48
5. R 12. 06
ОЬа dijagraшa su nacrtana u odnosu na izabrane re!erentne gubitke na nazivnoш
naponu Pcu2n glavnog, odnosno Pcu4n dodatnog trans!ormatora.
1,4
Pcu1,2,31ftu2n • Рс/Pon
1,0 ~----___;::::...."""'===-------
Q8
Sl. 3
Uziшajuci u obzir gornje pretpostavke i zaneшarenja шoguce је !ormulirati za-
visnost pojedinih gubitaka od sekundarnog napona.
Рcul ,;. Рcu2шaks • рcu2n ( U2n
2
u2шinJ
2
pcu3 • pcu3шaks u2шin
u2n - u2шin
Gubici u tercijarnoш regulacijskoш naшotsju Pcu3 su tako~e svedeni na re!eren-
tne gubitke Pcu2n' odnosno nazivnu snagu glavnog trans!ormatora.
Gubici u !eljezu glavnog trans!ormatora su neproшjenljivi tj. nezavisni od
proшjena napona na sekundarnoj strani.
Proшjenu gubitaka dodatnog trans!ormatora prikazuje sl. 4.
49
6. R 12 .О б
4 Ftut.lftuJ.n ' Ро/fЪmaks
2
1,0
0,4
81. 4
Tercijarni regulacijski nazotaj 3 daje uzbudnom namotaju 4 promjenljivi i in-
vertirani napon Ato ima za posljedicu promjenu guЬitaka u !eljezu u Airokom
rasponu od maksimalnih, kod napona u2min i u2maks' do nule kod napona u2n"
OЬlik krivulje guЬitaka u zeljezu се Ьiti priЬlizno zavisan od kvadrata regu-
liranog napona, а ta~nije vrijednosti је moguce odrediti za svaki konkretan
pri•jer poznavanjea kvaliteta upotrijeЬljenog ~agnetnog materijala.
( )
2
U - U
Fomaks 2 2n
u2n-u2maks
Usljed niskih i ndukcija u okol ini nazi vnog napona u2n donji dio krive guЬi t aka
ј е ekstrapol iran.
Uz priЬlizno jednake guЬitke u bakru u namotajima dodatnog transf ormatora vazi
relacija
Ukupni guЬici sistema su u svakom trenutku zЬir guЬitaka glavnog i dodatnog
transf ormatora. Predstavljeni su na slici 5· Na istoj slici је ucrtana i kriva
napona kratkog spoja do Ьijena mjerenjem na pomenutom r egulacijskom transforma-
toru.
50
7. R 12.06
u2
0,8 +-------+---------+--
U2min ~maks
Sl. 5
Zeliao li kriticki ocijeniti prikazani sistem, sa stanovista gubitaka, onda је
najbolje pore~enje izvesti sa klasicnim nacinom regulacije.
Gubici u bakru i !eljezu, kao i ukupni gubici, се biti veci ро cijelom obimu
regulacije.
Ха prikazanoa primjeru to povecanje se krece od 15 + 2о %za gubitke u !eljezu
i 2о + 25 %za gubitke u bakru. U ukupnom bilansu gubitaka, onih koji odre~uju
i sistem za hla4enje, porast је bio oko 2о %.
RazU&ljivo је da се se ti iznosi razlikovati i mijenjati od primjera do prim-
jera, ali u osnovi се biti odre~eni tipnom snagom dodatnog transformatora t.j.
obimos u kojes !elimo regulirati sekundarni napon. Pri tome moramo imati u
vidu, da је ovakvo rjesenje posljedica konstrukcijsko-tehnoloskih slaboвti
klasicnog nacina regulacije, ра је povecanje gubitaka potrebno prihvatiti kao
nu!nost i komprosiв za druge ugodnoвti koje pru!a ova izvedba.
3.2. Napon kratkog вроја
UoЬicajeni proЬlesi koji ве cesto postavljaju pred konвtruktora tranвformatora
вu uzrokovani zahtjevima za cim manjim odвtupanjem kratkoвpojne impedancije ро
oЬimu regulacije napona.
Izze~ zahtjeva narucioca, ekonomвke racunice i tehnoloskih mogucnosti pro-
izvo~aca, poвtoji uzajaana i tijeвna povezanoвt i niti jedan od tih pojmova
nije moguce rjesavati pojedinacno i nezaviвno od drugih.
Xaponвki nivo za tercijarni regulacijski namotaj, kao §to вmо vec rekli, oda-
biremo proizvoljno. Prakticno su to namotaji ва вtepenom izolacije Si 17,5 kV
do najviae Si 36 kV, ва kojisa је soguce obuhvatiti sirok spektar вnaga.
5.1
8. R 12.06
Razuшljiva је te!nja konвtruktora da uz jezgro poвtavi namotaj ва najni!im izo-
lacijвkim nivooш. u оvош i u vecini drugih вlucajeva, to је tercijarni-regula-
cijвki naшotaj. Polo!aj oвtala dva naшotaja се biti uвlovljen prvenstveno nji-
hoviш naponskiш i вtrujniш nivoiшa koji uglavnoш i uzrokuju cesta tehnoloska
ogranicenja pojedinih izvedbi.
Ako ве radi о priшarnia paponiшa jednakiш i visiш od llo kV i sekundarniш stru-
jaшa do 4ооо А onda је najugodniji raspored naшotaja kao na sl. б.
х
Sl. б
Radi li ве о jos visim вekundarniш strujaшa proЬlem treba rjesavati prvenstveno
ва aвpekta dodatnih gubitaka u kotlu i oвtalim !eljeznim dijeloviшa uzrokovanih
vezaшa izшedu оЬе jedinice. U tош slucaju niskonaponвki namotaj шоrа biti
vanjвki i iвtovremeno obuhvatiti оЬа шagnetna kruga, sto vodi ka potpuno novoj
koncepciji i tehnologiji izrade (niвkonaponвki namotaj u oЬliku broja 8).
Kod odredenog raвporeda i distanci izmedu namotaja, odstupanja napona kratkog
spoja се biti zavisna od snage tercijarnog-regulacijskog naшotaja. Rastom оЬiша
regulacije napona .хм linearno raste i snaga tog namotaja ра је tako sve veci
udio njegovog rasipnog polja u ukupnoш rasipnoш polju glavnog tranв!ormatora.
U tu svrhu smo prije izrade trans!ormatora teoretska ocekivanja provjerili si~
шulacijoш рrоЬlеша i шjerenjiшa na modelu. Kasnije su obavljena mjerenja napona
kratkog · вpoja ро cijeloш obimu regulacije napona na konkretnoш primjeru.
Rezultati шjerenja su u оЬа priшjera pokazali, da su odвtupanja bez veceg prak-
ticnog znacaja (sl. 5), te ih је шoguce obuhvatiti dozvoljenim tolerancijama
~ lo %vecine nacionalnih propiвa.
52
9. R 12.06
Odstupanja napona kratkog spoja uz raspored naшotaja na s1. б, ne6e predstav-
1jati рrоЬlем i za тесе snage trans!ormatora za koje је јоА uvijek шoguce
priшjeniti ovakvu izvedbu.
3.3. Tipna вnaga i cijena sisteшa
Mjeri1o za ocjenu nekog siвteшa је вnaga na koju је potrebno taj sisteш diшen
zionirati - tipna вnaga. Odrediti ju је шogu6e za svaki naшotaj i вvaki
trans!oraator pojedinacno. Oznacimo омјеr izшedu najviAeg i najnizeg napona na
вekundarnoj вtrani sa х. Ve1icina х predstav1ja re1ativni оЬiм regu1acije
х • U2aaks/U2min i najvaznija је karakteriвtika sisteшa. Sk1adno oznakaшa na
sl. 1 snage za diшenzioniranje su jednake:
pl • u1n11n • pn
р2 • u2ni2maks • pn (х+1)
2
р3 • u3шaks14шaks • Pn (х-1)
2
ptipg1 • Р1+Р2+Р2 Pn (х+1)
2 2
Ptipdod • u2maks - u2min 12maks •
2
Pn (х-1)
2
Rastoш оЬiша regu1acije sekundarnog napona 1inearno raste i tipna snaga dodat-
nog trans!orшatora koji ро ve1icini vr1o brzo шоzе dostici g1avni trans!orma-
tor. Та cinjenica је u вvаkом pog1edu neugodna obziro• da ве radi о povecanju
маsе i cijene sisteмa. Jedini nacin da se sшanji tipna snaga dodatne jedinice
је u tош s1ucaju reducirana snaga cjelokupnog sistema sto se, za vece оЬiше
regu1acije, u praksi cesto i cini.
Tipna snaga ukupnog sistema Ptip је, kod odredene snage tranв!ormatora, direk-
tno proporcionalna relativnom obiшu regu1acije вekundarnog napona.
Treba ocekivati da се tipna snaga biti i veca, jer ovli.ko izracunata ne uzi&a
u obzir izo1acijskih distanci koje је potrebno obezbijediti svakom naшotaju i
dodatnoш trans!ormatoru kao saшostalnoj jedinici. То povecanje је potrebno
uzeti u obzir, ровеЬnо onda, kad se radi о visiш naponiшa.
Tako odredenoj tipnoj snazi odgovaraju i ostali parametri - gubici, hladenje,
mase i u konacnom bi1ansu i cijena trans!ormatora.
53
10. R 12.06
Me4utia, iDtereaanten је bio izraaun raslike u cijeni k1aвiane 1 upotrijeЬljene
тar1jante u kojea је preвudnu ulogu 1grala 1zrazito v1soka razlika u cijeni
resulac1jвkih prekidaaa. Izraaun.je pokazao da је, pored anogih ostalih pred-
nosti, ovakaт na!iD regulacije kao cje1ina i je!tiniji te је tako regu1acija
ва dodatnia trans!oraatoroa naila 1 svoju ekonomsku opravdanost.
Realno је za oaekivati ras1iku u cijeni oko 1о ~ u koriвt prikazane regulacije.
Regulacija sekundarnog napona oвtтarena ва dodatnia tranв!ormatoro• u sekundar-
noa krugu iaa вlijedece najva!nije prednosti 1 osoЬine:
а) izrada transroraatora ве вvodi na klasianu. Izrada је jednostavna i ne zah-
t1jeтa posebne tehno1o!ke sahvate u proizvodnji
Ь) оЬе jedinice је •oguce projektirat1 neodтisno jedna od druge ро valec!R kri-
terijiaa za optiairanje
с) 1sbjeg11 s•o preklapanje v1sokih struja na sekundarnoj вtran1 а tiae i ugrad-
nju vr1o skupih 1 roЬustnih regu1acijskih prekidaaa
d) оЬа trans!oraatora вu s•je!tena u iвtoa kot1u.
Sa ekonoaskog stanoтi!ta gledano cijenu dodatnog trans!orиatora је vecinom шo
guce koapenzirati, uoЬiaajeno тeliko• razl1kom u cijeni visoko-strujnog preki-
daaa potrebnog sa klasiaan oЬlik regu1acije i upotrijeЬljenog pr ekidaaa u pri -
kazanoa siateau.
LITEIU!fUJU.
1. Е. Jesierвki:
2. 7. Coppadoroz
3. Р. Воn1в und
7. Coppadoro:
4. G. Scheael:
54
Trenв!orzator.y (podвtawy teoretyezne), Yarвzawa 1965.
La regolacione della tensione dei trans!orиatori per
l'aliaentazione dei !orni e1ettrici , "L'e1ettrotecni-
ca" , n.I vo1. LI-1964, Tecnoaasio- ВВС .
Tranв!oraatoren !Ur Lichtbogen-scЬ.elzo!en , ВВС
Druckвchri!t Br. ОВ-IУ 51о8бо D.
Lichtbogeno!en - Tranв!ormatoren !Ur die neuen
O!enreihen .&Ј! und ll, ВВС Mitteilungen, Baden 1979.