14 research outputs found
Struktur Komunitas Ikan Terumbu di Selat Sempu, Kabupaten Malang, Jawa Timur
No full textEkosistem terumbu karang memiliki banyak manfaat antara lain melindungi pantai dari gelombang dan arus yang kuat dan sebagai habitat, tempat bertelur, tempat berlindung dan sumber makanan bagi biota laut, salah satunya yaitu ikan terumbu. Ikan-ikan terumbu ini membentuk suatu komunitas di dalam ekosistem terumbu karang. Ikan-ikan tersebut memanfaatkan terumbu karang secara langsung maupun tidak langsung untuk kepentingan hidupnya. Sehingga apabila terumbu karang rusak atau hancur maka ikan terumbu juga akan kehilangan habitatnya. Selat Sempu memiliki terumbu karang yang tumbuh di sebelah timur dan barat Pulau Sempu. Kelimpahan ikan terumbu di perairan Selat Sempu mengalami penurunan, hal ini dikemukakan dari penelitian Luthfi pada tahun 2015, 2017 dan 2018. Terjadinya penurunan tutupan karang di perairan Selat Sempu ini diduga akibat eksploitasi masyarakat yang terus menerus dan adanya aktivitas manusia yang dapat menimbulkan kontaminan terhadap perairan.
Penelitian dilaksanakan pada bulan Oktober 2021 hingga Februari 2022 di perairan Selat Sempu, Kabupaten Malang. Pengambilan data dilakukan pada 5 stasiun yaitu Banyu Tawar, Jetty, Rumah Apung, Waru-Waru dan Watu Meja. Pada persentase tutupan karang, setiap stasiun dilakukan penanaman transek permanen sebanyak 5 buah secara purpossive sampling dan kemudian dilakukan monitoring setiap 2 bulan sekali. Pengambilan data kelimpahan ikan terumbu diambil dengan metode Underwater Visual Census. Pada masing-masing site dilakukan pengambilan data parameter oseanografi sebagai data penunjang. Tujuan dari penelitian ini yaitu untuk mengetahui kelimpahan, keanekaragaman, keseragaman, dan dominansi ikan terumbu di Selat Sempu, serta hubungan antara tutupan karang dengan kelimpahan ikan terumbu. Hasil pengambilan data karang diolah pada software CPCe dengan output berupa persentase tutupan, sedangkan data ikan terumbu diolah dengan Microsoft Excel dan SPSS kelimpahan dan hubungannya dengan tutupan karang hidup.
Hasil kelimpahan ikan terumbu di Selat Sempu mengalami peningkatan dari penelitian sebelumnya. Kelimpahan Ikan Terumbu di bulan Oktober 2021 sebanyak 0,57 ind/m2. Pada bulan Desember 2021, rata-rata nilai kelimpahan ikan terumbu di Selat Sempu 0,62 ind/m2. di bulan Februari 2022, rata-rata kelimpahan ikan di Selat Sempu sebanyak 0,57 ind/m2. Pada uji korelasi didapat nilai korelasi sebesar 0,64, sehingga hubungan antara tutupan karang hidup dan ikan terumbu berkategori “kuat”
Analysis of the Process of Resocialization of Homeless People on the example of Tartu Shelter
No full textKodutus on kõige äärmuslikum sotsiaalse tõrjutuse ja vaesuse vorm, mis mõjutab negatiivselt inimeste tervist ja heaolu ning avaldab suurt mõju majandusele ja ühiskonnale. Kodutuse probleem püsib aktuaalne ka Eestis. Kodutute taasühiskonnastamine on väheefektiivne ja keeruline protsess ning vajab tähelepanu. Oluline on ka mõista, kui keeruline on endistel kodututel taas iseseisvalt ühiskonnas hakkama saada ja millised tegurid ja protsessid on toetavad ja millised on takistavateks asjaoludeks kodutusest väljumisel. Lisaks kodutute individuaalsetele väljakutsetele mõjutab oluliselt nende taasühiskonnastamist ka ühiskond, mis sageli ei soodusta kodutute naasmist tavaellu. Stigmatiseerimine ja diskrimineerimine muudavad selle protsessi kodututele veel raskemaks. Uuringu eesmärk oli analüüsida kodutute resotsialiseerimise protsessi Tartu Varjupaiga näitel. Töö teoreetilises osas käsitleti kodutuse mõistet ja selle esinemist Eestis ja Euroopas ning anti ülevaade Eesti hoolekandesüsteemist ja kodututele sobivatest sotsiaalteenustest kohalike omavalitsuste tasandil. Töö empiirilises osas analüüsiti resotsialiseerimise protsessi Tartu Varjupaiga näitel. Autor viis uuringu läbi kombineeritud meetodiga. Kvantitatiivsed andmed teenuste kasutamise arvudest ja kodutute liikumisest erinevate teenuste vahel Tartu Varjupaigas aastatel 2014-2022 analüüsiti, kasutades statistilise analüüsi meetodit. Kvalitatiivse meetodina viidi läbi kuus intervjuud isikutega, kes on Tartu Varjupaigas läbinud kõik resotsialiseerimise etapid. Tulemused analüüsiti ja seostati Bronfenbrenneri ökoloogilise süsteemiteooria ja kodutute subkultuuri teooriaga.
Kvantitatiivsest analüüsist ilmnes, et vähenenud varjupaigateenuste kasutamine ja suurenenud liikumine majutusteenusele näitavad resotsialiseerimisprotsessi tõhusust, kuid väljakutsed, nagu sotsiaalmajutusteenuse pikendused ja sotsiaaleluruumidest tagasiliikumised, osutavad raskustele kodutute taasühiskonnastamisel. Intervjuudest selgus, et kodutuse põhjusteks olid peamiselt alkoholi- ja terviseprobleemid, töötus ning keerulised suhted lähedastega. Varjupaigas osutus keeruliseks sisse elamine ja alkoholist loobumine, mida sageli tarvitati tegevusetusest, sest päevaks pidi varjupaigaruumidest lahkuma. Puudus nii toidust kui ka privaatsusest tekitas stressi, samuti oli keeruline aru saada dokumentidest ja abiprotsessidest. Positiivse aspektina tõsteti esile sotsiaaltöötaja abi ning toetust töötukassast ja võlanõustamisest.
Sotsiaalmajutusteenusel olid probleemideks privaatsuse puudumine ja sobimatus toanaabritega, kes polnud harjunud enda järel koristama. Uusi sõprussuhteid oli keeruline luua ning suhtlus toanaabritega oli pealiskaudne. Sotsiaaltöötajate pakutud abist toodi välja toiduabi ning muud igapäevaelu ja majapidamisega seonduvat abi, väga oluliseks peeti võlgadega tegelemist, abi töövõime hindamisel ja dokumentide vormistamisel. Reeglid ja struktuur pakkusid tuge ja olid abiks korra hoidmisel ning eneseabi grupid olid suureks toeks eneseteadlikkuse tõstmisel.
Sotsiaaleluruumi saamist nimetasid kõik kliendid suurimaks abiks. Puudust tunti mööblist. Probleemideks olid alkoholi tarvitavad naabrid, kes joovad, varastavad, lärmavad, aga ka kehvad olmetingimused, mustus, hallitus ja prussakad. Endised kodutud püüavad mitte tarvitada alkoholi, aga sageli neil see ei õnnestu. Inimesed leidsid omale sõpru ja tekkisid kogukonnad, kus üksteist toetati. Sotsiaaltöötajate poole pöördutakse seoses toimetuleku- või ravimitoetuse taotlemisega ning sotsiaaleluruumi teenuse pikendamiseks, kuid üldiselt püütakse ise hakkama saada.
Endistel kodututel on olnud kodutusest väljumise teel nii paremaid kui ka halvemaid aegu. Kaks respondenti kirjeldasid seda keerulise ja raske protsessina, millest polegi väljapääsu. Soovitati lõpetada suhtlemine vanade sõpradega, kellega koos tarvitatakse alkoholi ning ainult üks vastaja kirjeldas protsessi, kuidas teha sügavat eneseanalüüsi, seada eesmärke, tegeleda võlgadega ja võtta vastutus oma elu eest.
Autor leiab, et pikaajaline alkoholisõltuvus, vaimse tervise probleemid ja kodutute piiratud ressursid on viinud olukorrani, kus nad leiavad, et neil puudub kontroll oma elu üle, nad on väsinud ja emotsionaalselt kurnatud. Inimesed on muutunud passiivseks ja nende motivatsioon on kadunud. Lühiajalise leevenduse saamiseks pöördutakse taas alkoholi poole, välditakse probleemide lahendamisi ja süvendatakse käitumismustreid, mis raskendab kodutusest väljumist.
Kodutute subkultuuri ja süsteemiteooria mõistmine näitab, kuidas negatiivsed käitumismustrid ja uskumused võivad muutuda takistuseks resotsialiseerumisel ning kuidas välise toetuse puudumine või ebapiisavus võib tugevdada tunnet, et nad ei suuda oma elu ise kontrollida või muuta. Seega on autori arvates oluline, et resotsialiseerimisprotsessis kaasataks mitmekülgseid toetusmeetmeid, mis arvestavad nii individuaalseid vajadusi kui ka süsteemset mõju, ning et pidevalt hinnataks ja kohandataks pakutavaid teenuseid vastavalt muutuvatele oludele ja kodutute vajadustele. Samuti on oluline luua teenuseid ja programme, mis on kättesaadavad ja vastavad kodutute vajadustele ning pakuvad neile turvalist keskkonda ja tuge. Lähenemine peaks olema individuaalne ja arvestama iga inimese vajadusi ja eluteed. Oluline on pakkuda tuge ja abi, et aidata neil taastada usk endasse ja valmisolek oma olukorda parandada. See peaks sisaldama endas emotsionaalset tuge, praktilist abi ja vahendeid ning pikaajalist toetust nende vajaduste rahuldamiseks.
Bronfenbrenneri süsteemiteooria kaudu saab näha kodutuse põhjuseid ja tagajärgi erinevatel süsteemitasanditel, ning see aitab paremini mõista olukorra komplekssust. Kodutute subkultuur, mis kujuneb välja vastuseks nende erilistele väljakutsetele ja keskkonnale, võib pakkuda nii toetust kui ka takistusi kodutusest väljumisel.
Tulenevalt uuringust, on autoril järgmised soovitused olukorra parendamiseks:
• Luua hindamisinstrument, mille abil hinnata kodututele pakutavate teenuste tulemuslikkust Tartu Varjupaigas;
• Koolitada varjupaiga personali teadlikkuse tõstmiseks ja kvaliteetsema teenuse tagamiseks;
• Arendada välja teenus, mis pakuks kodututele psühholoogilist või terapeutilist tuge nende vaimse tervise toetamiseks ja resotsialiseerumisprotsessi edendamiseks, kaasates kogemusnõustajaid, tugigruppe ning sõltuvusravi.
Uurimistöö eesmärk ja ülesanded said täidetud, kuid kodutute resotsialiseerimise protsess vajab põhjalikumat uurimist, sest antud tulemuste pealt ei saa teha mastaapsemaid üldistusi. Autori hinnangul andis töö väärtusliku sissevaate kodutute elu-olmesse ja sellest tulenevalt on võimalik parendada juba olemasolevaid teenuseid. Tasub uurida ka heade praktikate näiteid Eesti teistes linnades ja otsida võimalusi nende kohandamisel Tartu linna võimalustega.Homelessness is the most extreme form of social exclusion and poverty, which negatively affects people's health and well-being and has a major impact on the economy and society. The problem of homelessness remains relevant in Estonia as well.
Resocialization of the homeless is an inefficient and complex process and needs attention. It is also important to understand how difficult it is for former homeless people to manage independently in society again, and which factors and processes are supportive and which are hindering circumstances when leaving homelessness. In addition to the individual challenges of the homeless, their reintegration is also greatly influenced by society, which often does not encourage the homeless to return to normal life. Stigma and discrimination make this process even more difficult for the homeless.
The purpose of the study was to analyze the process of resocialization of the homeless using the Tartu Homeless Shelter as an example. In the theoretical part of the work, the concept of homelessness and its occurrence in Estonia and Europe was discussed, and an overview of the Estonian Welfare System and Social Services suitable for the homeless at the level of local governments was given. In the empirical part of the work, the process of resocialization was analyzed using the example of the Tartu Homeless Shelter. The author conducted the study using a combined method. Quantitative data on the number of services used and the movement of homeless people between different services in the Tartu Homeless Shelter in the years 2014-2022 were analyzed using the statistical analysis method. As a qualitative method, six interviews were conducted with persons who have gone through all stages of resocialization in the Tartu Homeless Shelter. The results were analyzed and related to Bronfenbrenner's ecological systems theory and homeless subculture theory.
The quantitative analysis revealed that the reduced use of shelter services and the increased movement to the accommodation service show the effectiveness of the resocialization process, but challenges such as extensions of the social accommodation service and returns from social housing indicate difficulties in the resocialization of the homeless.
The interviews revealed that the causes of homelessness were mainly alcohol and health problems, unemployment and difficult relationships with relatives.
Residents of the Homeless Shelter had difficulty adjusting and giving up alcohol, which was consumed due to inactivity. Stress was caused by the lack of both food and privacy, and misunderstandings with documents and aid processes. The help of a social worker and support from the Employment Department and debt counseling were noted as positive.
Users of the social accommodation service experienced problems of privacy and unsuitable roommates, as well as difficulties in establishing new friendships. Social workers provided important daily life and household support as well as dealing with debts and documents.
Getting social housing was a big help, but there were problems with neighbors who drink alcohol and poor living conditions. Former homeless people found support from each other and from social workers, but tended to turn to alcohol again.
The author believes that homeless people should be offered multifaceted support, taking into account their individual needs and life paths, and create services and programs that meet their needs and provide a safe environment and support.
Bronfenbrenner's systems theory helps to understand the causes and consequences of homelessness at different levels, and the homeless subculture can provide both support and barriers to exiting homelessness.
Based on the research, the author has the following recommendations for improving the situation:
• Create an evaluation instrument, which can be used to evaluate the effectiveness of the services offered to the homeless in the Tartu Shelter;
• Train Homeless Shelter staff to raise awareness and ensure better quality service;
• Develop a service that would provide psychological or therapeutic support to the homeless to support their mental health and promote the resocialization process, involving experienced counselors, support groups and addiction treatment.
The purpose and tasks of the research work were fulfilled, but the process of resocialization of the homeless needs a more in-depth study, because larger-scale generalizations cannot be made from the given results. According to the author, the work provided a valuable insight into the life of the homeless, and as a result, it is possible to improve existing services. It is also worth studying examples of good practices in other Estonian cities and looking for ways to adapt them to the possibilities of the city of Tartu
Teacher perceptions of the Georgia teacher evaluation program, 1990
Get PDFThe primary purpose of this study was to determine teacher percep�tions of the Georgia Teacher Evaluation Program. The study sought to determine the relationship between education and experience with regard to teachers' perceptions of the Georgia Teacher Evaluation Program. The study was conducted through the use of a validated twenty item questionnaire, designed and distributed by the Performance Assessment Laboratory of the University of Georgia. Sixty four certified teachers assigned to Paul D. West Middle School in Fulton County, Georgia for the 1989 90 school year were selected to record their responses to the survey statements listed in the questionnaire. An analysis of variance (ANOVA) and a t test were utilized. Find�ings indicated that teacher experience and level of educational attain�ment significantly affect teacher perceptions of validity and relia�bility of the Georgia Teacher Evaluation Program
Reliability assessment of tidal stream energy: significance for large-scale deployment in the UK
No full textThis is the author accepted manuscript. The final version is available from CRC PressThe UK has ambitious plans to harness its available tidal stream resource, estimated at 95TWh/year by The Crown Estate (2013). The economic viability of large-scale deployments will be largely governed by aspects of plant availability, including reliability. Using available information on environmental parameters of (pre-) consented sites across the UK, this paper explores subassembly target reliability levels for tidal stream devices. Reliability models of devices are investigated to establish the influence of environmental site conditions with regard to underlying subassembly failure rates and target reliability levels. Hence, a relia-bility-focussed perspective on the planned deployments is presented
Bayesian Network Approach to Assessing System Reliability for Improving System Design and Optimizing System Maintenance
Get PDFabstract: A quantitative analysis of a system that has a complex reliability structure always involves considerable challenges. This dissertation mainly addresses uncertainty in- herent in complicated reliability structures that may cause unexpected and undesired results.
The reliability structure uncertainty cannot be handled by the traditional relia- bility analysis tools such as Fault Tree and Reliability Block Diagram due to their deterministic Boolean logic. Therefore, I employ Bayesian network that provides a flexible modeling method for building a multivariate distribution. By representing a system reliability structure as a joint distribution, the uncertainty and correlations existing between system’s elements can effectively be modeled in a probabilistic man- ner. This dissertation focuses on analyzing system reliability for the entire system life cycle, particularly, production stage and early design stages.
In production stage, the research investigates a system that is continuously mon- itored by on-board sensors. With modeling the complex reliability structure by Bayesian network integrated with various stochastic processes, I propose several methodologies that evaluate system reliability on real-time basis and optimize main- tenance schedules.
In early design stages, the research aims to predict system reliability based on the current system design and to improve the design if necessary. The three main challenges in this research are: 1) the lack of field failure data, 2) the complex reliability structure and 3) how to effectively improve the design. To tackle the difficulties, I present several modeling approaches using Bayesian inference and nonparametric Bayesian network where the system is explicitly analyzed through the sensitivity analysis. In addition, this modeling approach is enhanced by incorporating a temporal dimension. However, the nonparametric Bayesian network approach generally accompanies with high computational efforts, especially, when a complex and large system is modeled. To alleviate this computational burden, I also suggest to building a surrogate model with quantile regression.
In summary, this dissertation studies and explores the use of Bayesian network in analyzing complex systems. All proposed methodologies are demonstrated by case studies.Dissertation/ThesisDoctoral Dissertation Industrial Engineering 201
The reliability of integrated reporting
Get PDFUK: В даній статті представлені висновки з аналізу надійності інтегрованої звітності в світлі стратегічної та інформаційної парадигми бухгалтерського обліку. Дослідження демонструє надійність в світлі міжнародних стандартів, які стандартизують інтегровану звітність, відповідно до якої існує необхідність в підвищенні довіри. В якості ключової форми підвищення надійності інтегрованої звітності автор вказує на внутрішню і зовнішню перевірку фінансових даних і їх розкриття, які засновані на звіті про управління, пов'язаному з відповідальністю підприємства. Мета дослідження була досягнута шляхом використання відповідних методів дослідження, включаючи, зокрема, критичний аналіз наукової літератури і метод аналогій. Дослідження носить аксіоматичний характер і ґрунтується на припущеннях фундаментальної теорії інституту бухгалтерського обліку. EN: The purpose of the article is to study the need and options for ensuring the relia-bility of integrated reporting using the methods of the Institute of Accounting.
Research results. This paper presents the conclusions from analyzing the reliability of integrated reporting in the light of the strategic and information-related paradigm of accounting. The study demonstrates the reliability in the light of international standards that standardize integrated reporting, according to which there is a need for the improvement of credibility. As a key form of improving the reliability of integrated reporting the author indicates an internal and external verification of financial data and non-financial disclosure, both based on accountability ac-count related to a company’s responsibility. The purpose of the study was achieved by employing pertinent research methods, including in particular a critical analysis of scholarly literature and the method of analogy. The study is axiomatic in nature, based on fundamental accounting theory assumptions.
Conclusions. Given the growing demand for information, it is expected that the sustainable development accounting system will be a proper tool for measuring asset value, capital and performance. Therefore, one of the key conditions for the development of integrated reporting by increasing its reliability is the development of verification and validation system and their adaptation to the needs that contribute to sustainable development
Sobre la justicia testimonial online. Matizando el optimismo de Karen Frost-Arnold acerca de la epistemología de la virtud
Get PDFIn Who Should We Be Online, Karen Frost-Arnold advocates an approach to epistemic virtues that resists pessimism about the possibility of our online epistemic agency being responsible and socially just. On the basis of a veritist episte-mology, her proposal overcomes both responsibi-list individualism and the socio-structural critique that delegates all responsibility to institutional transformations. The author identifies in online lurking an activity unique to online epistemic agency that can provide exposure to messages from people discriminated against by epistemic injustices. For Frost-Arnold, moreover, this implies the possibility of the lurker experiencing epistemic frictions that will favour a more relia-ble willingness to be fair in giving credit to the testimonies of those discriminated against. In this note I will qualify this optimistic stance, arguing the epistemic individualism that underlies it. I will point to a group virtue model as a possible solution.En Who Should We Be Online, Karen Frost-Arnold defiende una cierta aproximación a las virtudes epistémicas que resista al pesimismo acerca de la posibilidad de que nuestra agencia epistémica online sea responsable y justa. Sobre la base de una epistemología veritista, su propuesta supera tanto el individualismo responsabilista como la crítíca socio-estructural que delega toda responsabilidad en trans-formaciones institucionales. La autora identifica en el online lurking (fisgoneo online) una actividad exclusiva de la agencia epistémica online capaz de proporcionar una exposición a mensajes de personas discriminadas por injusticias epistémicas. Para Frost-Arnold, a su vez, esto implica la posibilidad de que el lurker experimente fricciones epistémicas que favorecerán una disposición más fiable a ser justos a la hora de dar crédito a los testimonios de personas discriminadas. En esta nota matizaré esta postura optimista, alegando el individualismo epistémico que subyace. Apuntaré a un modelo de virtudes grupales como posible solución
A Power System Reliability Evaluation Technique and Education Tool for Wind Energy Integration
Get PDFabstract: This thesis is focused on the study of wind energy integration and is divided into two segments. The first part of the thesis deals with developing a reliability evaluation technique for a wind integrated power system. A multiple-partial outage model is utilized to accurately calculate the wind generation availability. A methodology is presented to estimate the outage probability of wind generators while incorporating their reduced power output levels at low wind speeds. Subsequently, power system reliability is assessed by calculating the loss of load probability (LOLP) and the effect of wind integration on the overall system is analyzed. Actual generation and load data of the Texas power system in 2008 are used to construct a test case. To demonstrate the robustness of the method, relia-bility studies have been conducted for a fairly constant as well as for a largely varying wind generation profile. Further, the case of increased wind generation penetration level has been simulated and comments made about the usability of the proposed method to aid in power system planning in scenarios of future expansion of wind energy infrastructure. The second part of this thesis explains the development of a graphic user interface (GUI) to demonstrate the operation of a grid connected doubly fed induction generator (DFIG). The theory of DFIG and its back-to-back power converter is described. The GUI illustrates the power flow, behavior of the electrical circuit and the maximum power point tracking of the machine for a variable wind speed input provided by the user. The tool, although developed on MATLAB software platform, has been constructed to work as a standalone application on Windows operating system based computer and enables even the non-engineering students to access it. Results of both the segments of the thesis are discussed. Remarks are presented about the validity of the reliability technique and GUI interface for variable wind speed conditions. Improvements have been suggested to enable the use of the reliability technique for a more elaborate system. Recommendations have been made about expanding the features of the GUI tool and to use it to promote educational interest about renewable power engineering.Dissertation/ThesisM.S. Electrical Engineering 201
Dry clutch for automated manual transmissions. Structural analysis and control strategies
Get PDF2012 - 2013The goal of this thesis is the study of the automotive push-type dry clutches
used in the Automatic Manual Transmissions (AMTs) and in the Dual
Clutch Transmissions (DCTs) in order to improve their performances dur-
ing the engagements phases. The push-type clutch is very widespread in the
automotive sector because it allows many advantages in terms of cost, relia-
bility, isolation of vibrations to the driveline, reduced axial size and stability
to the facings wear [1]. Instead, the main advantages of an AMT, respect
to the Automatic Transmissions (ATs), are improvements in terms of safety,
reliability, and driving performances together with the reduction of the fuel
consumption and pollutant emissions [2]. For these reasons by mixing the
advantages of the push-type clutch with the advantages of the AMT it is
possible to attain very high performance [3, 4]. On the other hand, the
most important drawback of the AMT is the power interruption (the so
called "torque gap") during the gear shifts events. To solve this problem in
the last decade the DCTs have been introduced. In fact, by applying the
engine torque to one clutch just as the engine torque is being disconnected
from the other one [5] the torque transmission is allowed also during the
gear shift phases.
In this light, the work developed for this Thesis aimed at providing useful
information both to the clutch designers and to control algorithm designers
in order to enhance the performances, and consequently, the market di usion
mof the AMT and DCT transmissions.
The thesis is organized as follows. Chapter 2 is an introductory section on
the historical evolution of the clutches and of the automotive transmissions
systems. Chapter 3 deals with the transmissibility torque model by consid-
ering the main factors which a ect the elastic components of a push-type
clutch and the friction coe cient. In the Chapter 4 application of control
algorithms both for a two DoFs driveline model and for a ve DoFs model are introduced. Finally, the Chapter 5 underlines the concluding remarks. [edited by Author]XII n.s
The Diagnosis Technique of Abnormal Heating of Power Capacitors
Get PDFСуществующие системы защиты и диагностики не способны выявлять анормальный нагрев силовых конденсаторов, обусловленный развитием их внутренних неисправностей. В статье предлагается методика, позволяющая на ранней стадии обнаружить такой нагрев.
Данная методика содержит аппаратную часть и алгоритмы. Аппаратная часть состоит из микропроцессорного прибора, разработанного автором, измерительных трансформаторов тока и датчиков температуры. Это оборудование необходимо подключить к конденсаторной установке с номинальным напряжением 380 В. В процессе работы прибор осуществляет непрерывное измерение температуры поверхности корпуса каждого конденсатора установки, температуры внешней окружающей среды, напряжений и токов со стороны источника питания. Измеренные величины используются в математической модели тепловых процессов, позволяющей рассчитывать температуру наиболее нагретой точки каждого конденсатора в режиме
реального времени. Затем выполняется расчет характеристической разности между среднесуточными значениями температуры диэлектрика и начальным среднесуточным значением
этой температуры за вторые сутки от начала измерений. Если величина превысит значение абсолютной погрешности моделирования, то формируются диагностические сигналы
уровней опасности анормального нагрева: низкий, средний, высокий и очень высокий. Также необходимо выполнять расчет скорости изменения и учитывать полученные значения при формировании уровней опасности. При низком и среднем уровнях опасности анормального нагрева рекомендуется работа системы диагностирования на визуальный сигнал, при высоком уровне – работа на визуальный и звуковой сигналы, а при очень высоком уровне – на отключение конденсатора от сети. Приведенные алгоритмы разработаны эвристически. Окончательное их формирование возможно только после многолетней эксплуатации предлагаемой системы диагностирования на реальных объектах. Внедрение разработанной системы снизит вероятность внезапного отказа конденсаторных установок и соответственно повысит надежность системы электроснабжения предприятия.The existing system of protection and diagnostics are not able to detect abnormal heating of the power capacitors caused by its internal malfunction formation. The paper contains a proposal of a technique that enables to detect such heat at its early study. This technique consists
of a hardware and an algorithms. The hardware consists of a microprocessor-based instrument developed by the author, of measuring transformers of current and of temperature sensors. This
equipment must be connected to the condenser unit with a rated voltage of 380 V. In operation, the device performs continuous measurement of the surface temperature of the casing of each condenser, the temperature of the external environment, voltage and current from the power source.
The measured values are used in the mathematical model of thermal processes that enables to calculate the temperature of the hottest point of each capacitor in real-time. Then the calculation of the intrinsic difference between the average temperature values of the dielectric and the base
average value of this temperatures during the second day from the start of the measurements. If the value exceeds the value of the absolute error of simulation, diagnostic signals of abnormal levels
of heating, viz. low, medium, high and very high, are generated. It is also necessary to calculate the rate of change of and to consider the values obtained in the formation of hazard levels. For the low level and the average level of hazard the operation of diagnostic system with a visual signal is recommended,
while for the high level of hazard it is recommended to use both visual and sound signals, and for the very high hazard level the capacitor ought to be turned off from the source. The algorithms have been
developed heuristically. The final formation of the algorithms is possible only after the long-term operation of the proposed diagnosis system on real objects. The implementation of the developed system will
reduce the probability of sudden failure of capacitor units and, correspondingly, will increase the relia bility of power supply system of enterprise
