- Type of paper
: Book
Title: Expression of measurement result
- Authors:
- Godec, Zdenko (13636)
- Editors
- Benčić, Zvonko
Publisher: Graphis
ISBN: 953-96399-1-3
Year: 1995
Number of pages: 68
Number of references: 29
Language: hrvatski
Summary: Definitions are given wich are essential for understanding
a new expression of measurement result. Methods of evalution of standard
uncertainty from available data and previosly used quality expressions of
measurement resutls which harmonize with internatiobal agreement are
elaborated. Proposed are three quality levels for expressing measurement
result (scientific, expert and rutine), which confirm with purpose of
measurement.
Keywords: measurement, result of measurement, uncertainty, standard uncertainty
Other:
- Type of paper
: Paper in journal
Title: How to use heat from a transformer
- Authors:
- Godec, Zdenko (13636)
Journal: Energija
Number: 6
ISSN: 0013-7448
Volume: 40
Year: 1991
Pages: from 409 to 413
Number of references: 22
Language: hrvatski
Summary: Technical considerations, possibilities and limitations on
the conversion of a low-temperature waste transformer heat into useful
energy for heating is described. Review is given considering conditions
which, if fulfilled, provide undisturbed and reliable transformer work.
Significant savings can be expected when the usage of trasfnormer waste
heat is planned in advance, and somewhat less signifcant if the equipment
is built in subsequently.
Keywords: transformer, power losses, waste heat, low temperature heating
- Type of paper
: Paper in journal
Title: Overload protection of oil-immersed distribution
transformers
- Authors:
- Godec, Zdenko (13636)
Journal: Energija
Number: 5
ISSN: 0013-7448
Volume: 41
Year: 1992
Pages: from 303 to 309
Number of references: 12
Language: hrvatski
Summary: Protection of oil-immersed distribution transformers with
maximumrating of 2500 kVA is usually reduced to obligatory
short-circuitprotection, and sometimes overload protection. The
overloadprotection is realized by over-temperature relay, which limitsthe
temperature of oil, or by over-current relay which limits theload current.
It is demonstrated that transformer could bereliably protected only by
using combined and harmonisedoperation of bouth relays.
Keywords: Distribution transformers, Overload, Protection
- Type of paper
: Paper in journal
Title: Steady-State Temperature Rise Determination
- Authors:
- Godec, Zdenko (13636)
Journal: Automatika
Number: 3-6
ISSN: 0005-1144
Volume: 33
Year: 1992
Pages: from 129 to 133
Number of references: 18
Language: engleski
Summary: In absence of appropriate criterion, the determination
ofsteady-state temperature rise is often incorrect. As aconsequence, the
determination of all of thetemperature-dependent characteristics becomes
also incorrect. Amethod that ensures a reliable determination of
steady-statetemperature rise within the shortest time possible ispresented.
The objective is also to extend this method - whichhas been implemented and
verified on transformers - to othertechnical fields.
Keywords: Temperature-rise, Regular regime, Measurements, Mathematical techniques, Steady-state temperature rise
- Type of paper
: Paper in journal
Title: Normal ambient temperature conditions for transformers
- Authors:
- Godec, Zdenko (13636)
Journal: Elektrotehniški vestnik
Number: 1
ISSN: 0013-5852
Volume: 60
Year: 1993
Pages: from 23 to 26
Number of references: 28
Language: engleski
Summary: The normal ambient service conditions for all kinds
oftransformers should be defined as ambient conditions of Moderategroup of
statistical open-air climates. Design of transformerintended for
installation on site with Extremely Cold and Coldtypes of climate should be
appropriately adapted. In hot climatesthe transformer standard temperature
rise limits shall be reducedif the weighted mean annual temperature exceeds
20 degreeCelsius.
Keywords: Transformers, Service conditions, Climate, Temperature-rise, Ambient temperature
- Type of paper
: Paper in journal
Title: Winding Thermal Image Protection of Power Transformers
- Authors:
- Godec, Zdenko (13636)
Journal: Energija
Number: 6
ISSN: 0013-7448
Volume: 42
Year: 1993
Pages: from 371 to 375
Number of references: 18
Language: hrvatski
Summary: Winding thermal image is still the best and most
reliabletransformer protection against overload and overheating.
Theadvantages of this type of protection is compared to contactthermometer
or thermostat protection. If resistance thermometerand microprocessor are
used, measurement uncertainty can besignificantly reduced. A potentially
better protection based onthe direct hot-spot measurement with fibber-optic
thermometer isso far at the state of experiment.
Keywords: Transformer, Power transformer, Winding thermal image, Hot-spot, Mathematical model, Simulation, Protection, Overload, Overheating, Measurement uncertainty
- Type of paper
: Paper in proceedings
Title: Heat transfer from corrugated tanks to air
- Authors:
- Godec, Zdenko (13636)
Proceedings title: 3.Međunarodni simpozij o novim tehnologijama
Language: hrvatski
Place: Zagreb
Year: 1991
ISBN/ISSN: 86-81997-04-1
Pages: from 19 to 19
Meeting: III simpozij o novim tehnologijama
Held: from 10/15/91 to 10/17/91
Summary: The main aims and first results of the investigation on
theproject 2-05-241: "Cooling with corrugated tank" are explained.
Keywords: Corrugated tank, Natural cooling, Temperature rise, Steady state temperature rise, Experiments, Measurements, Physical model, Mathematical model, Oil-immersed transformer, Distribution transformer
- Type of paper
: Paper in proceedings
Title: Use of heat from a transformer
- Authors:
- Godec, Zdenko (13636)
Proceedings title: XX.savjetovanje JUKO-CIGRE, I.sekcija-Elementi postrojenja, Grupa 12, Transforma
Language: hrvatski
Place: Zagreb
Year: 1991
Pages: from 79 to 88
Meeting: XX savjetovanje elektroenergetičara Jugoslavije
Held: from 04/21/91 to 04/26/91
Summary: Technical considerations, possibilities and limitations on
theconversion of a low-temperature waste transformer heat intouseful energy
for heating is described. Review is givenconsidering conditions which, if
fulfilled, provide undisturbedand reliable transformer service. Significant
savings can beexpected when the usage of transformer waste heat is planned
inadvance, and somewhat less significant if the equipment is builtin
subsequently.
Keywords: Transformer, Power loss, Waste heat, Low temperature heating
- Type of paper
: Paper in proceedings
Title: Transformers with forced directed oil flow
- Authors:
- Podobnik, Vladimir (84053)
- Šarunac, Radovan (46141)
Proceedings title: XX savjetovanje JUKO-CIGRE, I sekcija-Elementi postrojenja, Grupa 12, Transforma
Language: hrvatski
Place: Neum, Jugoslavija
Year: 1991
Pages: from 79 to 88
Meeting: XX savjetovanje elektroenergetičara Jugoslavije
Held: from 04/21/91 to 04/26/91
Summary: Design of transformers with directed oil circulation in
thecooling ducts of windings (OD) is described, and effects thatare
attained are analysed. The technical-economic analysis ofapplication of OD
cooling can help the users in choosing the typeof transformer cooling.
Keywords: Transformer, Directed oil circulation, Windings, Technical-economic analysis, Temperature rise
- Type of paper
: Paper in proceedings
Title: Steady-state temperature rise determination
- Authors:
- Godec, Zdenko (13636)
Proceedings title: Zbornik radova KoREMA 37(1992) 1. svezak
Language: engleski
Place: Zagreb
Year: 1992
ISBN/ISSN: 86-81571-11-7
Pages: from 311 to 314
Meeting: 37. Međunarodni godišnji skup KoREMA
Held: from 04/26/92 to 04/29/92
Summary: In absence of appropriate criterion, the determination
ofsteady-state temperature rise is often incorrect. As aconsequence, the
determination of all of thetemperature-dependent characteristics become
also incorrect. Amethod that ensures a reliable determination of
steady-statetemperature rise within the shortest time possible is
presented.The objective of the paper is to extend this method - which
hasbeen implemented and verified on transformers - to othertechnical
fields.
Keywords: Measurements, Temperature rise, Regular regime, Mathematical techniques
Other: članak je odabran za objavljivanje u žasopisu AUTOMATIKA
- Type of paper
: Paper in proceedings
Title: Life Extension of Power Transformer Insulating System
- Authors:
- Mikulecky, Anton (134543)
- Godec, Zdenko (13636)
- Čabrajac, Sonja (7516)
Proceedings title: Obnova i izgradnja elektroenergetskog sistema Republike Hrvatske
Language: hrvatski
Place: Zagreb
Year: 1992
Pages: from 402-1 to 402-3
Meeting: HK-CIGRE stručna konzultacija: Obnova i izgradnja elektroenergetskog sistema Republike Hrvatske
Held: from 05/26/92 to 05/27/92
Summary: From the view of aging, a large number of transformers in
use bythe Croatian Electric Power-Supply Company (Hrvatskaelektroprivreda)
can be considered to have degraded reliabilityof operation. This discussion
is aimed to direct the attention oftransformer users to the problems of
transformer insulationaging, and to point to some possible solutions.
Keywords: Power transformer, Insulation, Aging, Life extension
- Type of paper
: Paper in proceedings
Title: Power transformers in difficult cooling conditions
- Authors:
- Godec, Zdenko (13636)
Proceedings title: Obnova i izgradnja elektroenergetskog sistema Republike Hrvatske
Language: hrvatski
Place: Zagreb
Year: 1992
Pages: from 216/1 to 216/3
Meeting: HK-CIGRE stručna konzultacija: Obnova i izgradnja elektroenergetskog sistema Republike Hrvatske
Held: from 05/26/92 to 05/27/92
Summary: The guidance is given how to prevent the overheating and
how tolimit the aging of transformers in difficult cooling conditions(due
to defending wall in, decreased number of radiators,overloading) by means
of winding thermal image or contactthermometer and load current.
Keywords: Power transformer, Cooling, Temperature rise, Aging, Protection, Winding thermal image, Contact thermometer
- Type of paper
: Paper in proceedings
Title: Thermal Modeling of Oil-immersed Transformers
- Authors:
- Godec, Zdenko (13636)
- Editors
- Benčić, Zvonko (3062)
Proceedings title: Modeli izmjene topline u električnim uređajima
Language: hrvatski
Place: Zagreb
Year: 1992
ISBN/ISSN: 92 1222096
Pages: from 51 to 72
Meeting: Modeliranje u znanosti, tehnici i društvu, Hrvatsko društvo za sustave
Held: from 10/21/92 to 10/21/92
Summary: Two thermal models are presented for modeling of
steady-statetemperature rises: one for distriburion transformers
withcorrugated tank, the other for large transformers withONAN/ONAF/OFAF
cooling. Two models for transient thermal behaviorare also presented.
Winding thermal image is a hardware modelthat simulates winding hot-spot
temperatures. The other ismathenatical model on which a more accurate
method forsteady-state temperature rise determination at temperature
risetests is based.
Keywords: Transformers, Thermal state, Steady-state thermal state, Transient thermal state, Modelling, Simulation, Corrugated tank, Winding thermal image
- Type of paper
: Paper in proceedings
Title: Computer Program for Processing of Transformer Temperature
Rises Results
- Authors:
- Rezić, Ante (93615)
- Godec, Zdenko (13636)
- Editors
- Benčić, Zvonko
Proceedings title: Modeli izmjene topline u električnim uređajima
Language: hrvatski
Place: Zagreb
Year: 1992
ISBN/ISSN: 92 1222096
Pages: from 167 to 171
Meeting: Modeliranje u znanosti, tehnici i društvu, Hrvatsko društvo za sustave
Held: from 10/21/92 to 10/21/92
Summary: Based on a new and standardized method of
steady-statetemperature rise measurements of oil-immersed transformers,
acomputer program has been made for processing and graphicalrepresentation
of results. The program can be modified forprocessing and representing of
temperature rise measurements ofany device or process.
Keywords: Temperature, Temperature rise, Heat run, Measurements, Software, Graphical representation
- Type of paper
: Paper in proceedings
Title: Proposal of Overload Protection of Oil-Immersed
Distribution Transformers
- Authors:
- Godec, Zdenko (13636)
- Harča, Stjepan (15324)
Proceedings title: Prvo savjetovanje Hrvatskog komiteta CIGRE, I. sekcija - Elementi postrojenja
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 265 to 269
Meeting: I. Savjetovanje Hrvatskog Komiteta CIGRE
Held: from 10/10/93 to 10/13/93
Summary: The overload protection of oil-immersed distribution
transformersup to 2500 kVA is usually realized with over-temperature
orover-current relays. Each of both does not protect transformersin all
service conditions from too high hot-spot temperatures andtoo rapid thermal
aging of insulation. For this reason twoinexpensive combined overload
protections are proposed. The firstone is for existing transformer
substations, and the second oneis appropriate for up-to-date transformer
substations withSF6-gas insulated switchgear.
Keywords: Distribution transformers, Overload, Aging, Protection
- Type of paper
: Paper in proceedings
Title: Loading of Oil-Immersed Transformers According to the New
IEC Standard and Readjustement of Winding Temperature Indicator
- Authors:
- Godec, Zdenko (13636)
Proceedings title: I. savjetovanje Hrvatskog komiteta CIGRE, I. sekcija - Elementi postrojenja
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 195 to 202
Meeting: I. Savjetovanje Hrvatskog Komiteta CIGRE
Held: from 10/10/93 to 10/13/93
Summary: The changes compared to old IEC standard are stressed. One
ofthis changes (winding hot-spot factor increase) demandreadjustment of
winding temperature indicator on most medium andlarge power transformers. A
new method for winding temperatureindictor adjustment is explained.
Keywords: Power transformers, Loading, Winding temperature indicator
- Type of paper
: Paper in proceedings
Title: Accuracy, precision, error and uncertainty of measurement
result
- Authors:
- Godec, Zdenko (13636)
- Editors
- Štambuk-Boršić, Neda
Proceedings title: 40.jubilarni godišnji skup KoREMA
Language: hrvatski
Place: Zagreb
Year: 1995
ISBN/ISSN: 953-6037-08-4
Pages: from 259 to 264
Meeting: 40. jubilarni godišnji skup KoREMA
Held: from 04/19/95 to 04/21/95
Summary: Definitions are given which are essential for understanding
a new expression of an uncertainty in measurement. Methods of evaluation of
standard uncertainty from available data and previously used quality
expressions of measurement results which harmonize with international
agreement are elaborated. Three quality levels for expressing measurement
result which confirm with purpse of measurement are proposed.
Keywords: measurement, result of measurement, measurement's uncertainty
- Type of paper
: Paper in proceedings
Title: Power transformer as heat source
- Authors:
- Godec, Zdenko (13636)
- Editors
- Franković, Bernard
Proceedings title: Energija i zaštita okoliša
Language: hrvatski
Place: Opatija
Year: 1994
ISBN/ISSN: 953-96054-2-3
Pages: from 85 to 92
Meeting: Međunarodni kongres ENERGIJA I ZAŠTITA OKOLIŠA, XIV. Znanstveni skup o energiji i zaštiti okoliša
Held: from 10/26/94 to 10/28/94
Summary: Oil-immersed power transformer in operation releases about
4 kW of power losses per every MVA of its name plate rating. In the
Republic of Croatia is about 13 GVA of total power of installed power
transformers for voltages above 35 kV. This makes a potential of about 52
MW of power that can be utilized for space and water heating. Today,
transformer power losses produce waste heat flow - heat that is dissipated
to the atmosphere via transformer cooling equipment. Technical solutions,
possibilities and limitations on the transformation of lov-temperature heat
of oil-immersed power transformers with natural oil and natural and forced
air cooling (ONAN and ONAN/ONAF) are discussed.
Keywords: Transformer, Power losses, Waste heat, Low temperature heating
