1,723,376 research outputs found
A diagnostic method for moisture intrusion fault in OIP bushing
No full textOil-impregnated paper (OIP) bushing is essential equipment in power substations, and moisture intrusion is one of the major faults during its operation. In this article, a method is proposed to diagnose the moisture intrusion fault by the hidden Markov model (HMM) and the shuffled frog-leaping algorithm (SFLA). First, HMM is employed to characterize the probabilistic relationship between the moisture states and frequency-domain spectroscopy (FDS). Then, SFLA is adopted to optimize the locatable results of moisture intrusion point (MIP) in the bushing. Next, extensive simulated data are used for parameter training in the HMM-SFLA model library, with cross-validation for optimal parameters' configuration of HMM and SFLA. Finally, the proposed method was validated by experiment in laboratory and field measurements. The results show that the proposed method can effectively diagnose the MIP of OIP bushings
PEMELIHARAAN BUSHING TRAFO NO. 4
No full textDilapangan dijumpai juga kasus yang bermasalah, baik dari awal perencanaan, prosedur pemeliharaan bahkan pemeliharaan yang kurang baik sehingga kinerja Bushing Trafo sendiri tidak bisa optimal. Oleh karena itu perencanaan dan prosedur kinerja Bushing Trafo distribusi pada jaringan tegangan menengah harus diperhatikan dan yang lebih penting lagi, sebelum Bushing Trafo dipakai sebaiknya diuji terlebih dahulu supaya dapat memastikan bahwa Bushing Trafo yang akan digunakan betul-betul baik dan tepat nilai transformasinya. Tujuan Penelitian adalah mengetahui cara pemeliharaan Bushing Trafo distribusi yang baik dan benar untuk dipakai pada jaringan tegangan menengah 25 KV Metode Penelitian dengan teknik Observasi, Peneliti mengadakan suatu pengamatan secara langsung dari semua peralatan yang dikerjakan. Dengan metode ini penyusun dapat mengetahui secara pasti tentang peralatan tersebut. Dan Metode ini dilakukan dengan cara membaca buku-buku literatur yang dijadikan referensi untuk memperoleh data. Dengan demikian Peneliti menjadi lebih tahu dan jelas tentang peralatan atau perlengkapan yang dipasang pada Bushing Trafo di jaringan distribusi Hasil Penelitian : Tegangan pada Bushing Trafo distribusi selalu dinaikkan sampai dengan 5%. Hal ini dimaksudkan agar dapat mengantisipasi terjadinya drop tegangan pada saluran dengan rincian sbb: 1. Maksimum 3% hilang pada saluran antara pembangkit (dalam hal ini Bushing Trafo distribusi) sampai dengan sambungan rumah. 2. maksimum 1% hilang pada saluran antara sambungan rumah sampai dengan KWh meter. 3. Maksimum 1% hilang pada saluran KWh meter - panel pembagi - alat listrik terjauh. Semakin besar rugi daya dalam persen, berarti semaki besar kerugian energi yang terjadi. Kata Kunci: Bushing, trafo,gardu induk, 150 KV, Kebase
Target Driven Bushing Design for Wheel Suspension Concept Development
No full textBushing elasticity is one of the most important compliance factors that significantly influence driving behavior. The deformations of the bushings change the wheel orientations under external forces. Another important factor of bushing compliance is to provide a comfortable driving experience by isolating the vibrations from road irregularities. However, the driving comfort and driving dynamics are often in conflict and need to be balanced in terms of bushing compliance design. Specifically, lateral force steer and brake force steer are closely related to safety and stability and comprises must be minimized. The sensitivity analysis helps engineers to understand the critical bushing for certain compliance attributes, but optimal balancing is complicated to understand. The combination of individual bushing stiffness must be carefully set to achieve an acceptable level of all the attributes. Traditional bushing tuning method involves an optimization process in Adams Car or any other multi-body simulation software. Though they provide reliable results, it is a time-consuming process to build models for the complete Kinematic and Compliance analysis. Therefore, a method to set the bushing specifications automatically according to the compliance targets is proposed by the author. The method makes sure the instant motion of the wheel meets the targets. The bushing stiffness values are calculated according to force distribution and motion ratios between the wheel and each bushing. The method decouples the axial stiffness and radial stiffness. It provides a method to set up the radial stiffness automatically. The new method will reverse the traditional trial-and-error approach, to avoid extensive iterations and significantly reduce the development time
Target Driven Bushing Design for Wheel Suspension Concept Development
No full textBushing elasticity is one of the most important compliance factors that significantly influence driving behavior. The deformations of the bushings change the wheel orientations under external forces. Another important factor of bushing compliance is to provide a comfortable driving experience by isolating the vibrations from road irregularities. However, the driving comfort and driving dynamics are often in conflict and need to be balanced in terms of bushing compliance design. Specifically, lateral force steer and brake force steer are closely related to safety and stability and comprises must be minimized. The sensitivity analysis helps engineers to understand the critical bushing for certain compliance attributes, but optimal balancing is complicated to understand. The combination of individual bushing stiffness must be carefully set to achieve an acceptable level of all the attributes. Traditional bushing tuning method involves an optimization process in Adams Car or any other multi-body simulation software. Though they provide reliable results, it is a time-consuming process to build models for the complete Kinematic and Compliance analysis. Therefore, a method to set the bushing specifications automatically according to the compliance targets is proposed by the author. The method makes sure the instant motion of the wheel meets the targets. The bushing stiffness values are calculated according to force distribution and motion ratios between the wheel and each bushing. The method decouples the axial stiffness and radial stiffness. It provides a method to set up the radial stiffness automatically. The new method will reverse the traditional trial-and-error approach, to avoid extensive iterations and significantly reduce the development time
Development of a MR Hydraulic Bushing for Automotive Applications
No full textI hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii The purpose of this work is to design a semi-active magnetorheological (MR) hydraulic bushing. The semi-active bushing is intended to be used to isolate a cylinder deactivating engine. Cylinder deactivation causes high transient torsional loading in addition to changing the magnitude and mode of engine vibrations requiring an adaptive or controllable isolator. Practical and simple semi-active control strategies are inspired by investigating the optimization of linear and slightly cubic nonlinear single degree of freedom isolators. Experimental verification of the optimization technique, which minimizes the root mean square (RMS) of engine acceleration frequency response and RMS of the force transmitted frequency response, shows that this method can be implemented on real linear systems to isolate the engine from harmonic inputs. This optimization technique is also applied to tune selected model parameters of existing two degree of freedom hydraulic bushings. This thesis also details the development of a MR hydraulic bushing. The MR bushing design retrofits an existing bushing with a pressure driven flow mode valve on the inertia track. A new efficient valve design is selected and developed for the application. The MR hydraulic bushing is designed, mathematically modeled, and numerically simulated. The simulation results show that the MR bushing tends to increase the low frequency dynamic stiffness magnitude while simultaneously decreasing the phase. The next stage of the project is fabrication and testing of the semi-active bushing. The performance of the manufactured MR bushing is tested on a base excitation apparatus. Varying the current input to the MR valve was found to have a small effect on the response of the suspended mass. The results are in agreement with the effects demonstrated by the dynamic stiffness numerical simulation. ii
Numerical analysis of bushing of car stabilizer
No full textThe goal of this work is to create numerical model, which will be used for design and optimization of a rubber bushing of stabilizer bar. Thanks this model we are able to predict the mechanical behavior of the bushing. To get material constants for the model, the material of bushing (rubber) was tested in special deformations modes. A hyperelastic material model was set and it was implemented into the numerical model of the bushing. Critical points in the construction of bushing were reveled by the analysis of the numerical model
Insulation assessment of high voltage oil impregnated paper bushing and resin impregnated paper bushing
Get PDFTransformer diagnostic testing is perform to reveal the condition of the transformer. Early detection of problems can minimize the repairs involved and mitigate catastrophic failures. CIGRE findings show that bushings are common reason for power transformer failures. There are few research development conducted over the years to improvise construction of condenser bushings. One of the first technologies was the Resin Bonded Paper (RBP), but not manufactured anymore due to many technical & environmental reason. Secondly and the most widely used is Oil Impregnated Paper (OIP) technology apparently because of its low primary cost. In the circumstances? whenever there is problem with the insulation or internal degradation, it can accumulate high internal pressure inside bushing which can cause explosion of OIP bushing. That why migration from Oil Type to Dry Type Bushing Technology chosen to reduce risk of explosion /caught in fire during bushing failures .The new safer alternative considered is the Resin Impregnated Paper (RIP) technology which offer better technical performance over OIP bushings. This study presents comparison on insulation assessment of both types of bushing through power factor measurement and dielectric frequency response (DFR) analysis that contributing to assessment of failure characteristics of OIP and RIP bushings. Field testing was implemented to capture data for comparison purpose focusing on selection power transformer in grid division installation. The measurement of bushing insulator capacitances and measurement of the dissipation factor is to determine bushing health condition while DFR measurements as a supporting diagnostic tool for bushing condition assessment on paper inside the bushing. Commonly, both OIP & RIP constructions are that they are subject to very high mechanical, electrical and thermal stresses during operation. With result of this study, it may become possible to identify failure characteristic of insulating material between Oil Impregnated Paper Bushings (OIP) and Resin Impregnated Paper Bushings (RIP) and explain that moisture content in oil and paper has significantly contributed to the degradation of bushing. This methodology can be utilize for effective way to monitor moisture content at site and as a tool to decide condition of insulation bushing
Bushing Extractor and Inserter
No full textPatent for the creation of a manner in the method of bushing extractors and inserters
Transient Voltage Distribution in Bushing
No full textAn electrical bushing is one of the most important elements in a power transformer. Steep front surges such as transient impulse voltage from lightning strikes is an inevitable electromagnetic transient mostly happening in power transmission and distribution system. The bushing might lead to be degraded due to such kind of surge. This project deals with overvoltage stress distribution on the transformer bushing under the effect of electromagnetic transient response such as lightning impulse. To understand the behavior of transient response on the bushing, a proper model of power transformer bushing is built-in Comsol multiphysics to authenticate the stress distribution. The electromagnetic wave of impulse propagates onto the overhead line that connects with the transformer. Some understanding of the transient behavior of a conductor bushing has been achieved through studying the influence of inductance property and the skin effect characteristics of a multi-layer coaxial cable on the wave propagation, which has been structured in this project to simplify the model. On the other hand, the skin effect analysis on the conductor of the bushing has been taken also into account in this project using real conductor simulation in the Comsol model. Thus, it will be interesting to compare the real conductor model with the perfect conductor of the bushing through analyzing the current density effect on it. In this project, multi-layer of coaxial cable and transformer bushing are simulated. The simulation is carried out for time domain and frequency domain in Comsol based on the model characteristics. En elektrisk genomföring är ett av de viktigaste elementen i en transformator. Spänningsvågor med branta fronter som impulsspänningar från blixtnedslag är ett oundvikligt elektromagnetiskt övergående fenomen som oftast sker i kraftöverförings- och distributionssystem. Genomföringen kan leda till att degraderas på grund av en sådan våg. Detta projekt handlar om fördelning av överspännings på transformatorgenomföringen under påverkan av elektromagnetisk transient respons, såsom blixtimpuls. För att förstå beteendet hos övergående respons på genomföringen är en korrekt modell av transformatorgenomföring inbyggd Comsol-flerfysik för att autentisera spänningsfördelningen. Den elektromagnetiska impulsvågen fortplantas från luftledningen som ansluter till transformatorn. Viss förståelse för det övergående beteendet hos en ledargenomföring har uppnåtts genom att studera påverkan av induktansegenskaper och hudeffektegenskaperna hos en flerskikts koaxialkabel på vågutbredningen, vilket har strukturerats i detta projekt för att förenkla modellen. Å andra sidan har hudeffektanalysen på genomföringens ledare beaktats i detta projekt med användning av verklig ledarsimulering i Comsol-modellen. Således blir det intressant att jämföra den riktiga ledarmodellen med den perfekta ledaren för genomföringen genom att analysera strömtäthetseffekten på den. I detta projekt simuleras flerskikt av koaxialkabel och transformatorgenomföring. Simuleringen utförs för tidsdomän och frekvensdomän i Comsol baserat på modellegenskaperna
Advanced bushing script program in MSC ADAMS
No full textThe thesis focuses on investigating and optimizing a bushing script implemented as a tool in MSC ADAMS/Car. The study provides an insight on the representation of a rubber bushing and identify parameters which can be used to define the properties of a bushing in a simulation environment such as ADAMS/Car. The tool being studied here can be used to implement different kind of bushings such as a hydro bushing and a general rubber bushing, but optimization was implemented for the rubber bushing only. With an increasing reliance on Computer Aided Engineering (CAE) tools in the designing process, it is necessary that the vehicle behaviour can be predicted without relying on physical testing. CAE tools reduces the need of prototypes and provides a faster approach to designing vehicles. MSC ADAMS/Car is one such tool, which has been used here to predict the vehicle dynamic behaviour, which will influence the ride, handling and comfort characteristics of the vehicle. Rubber bushings, which have been studied here, have a significant contribution to the overall stiffness of the vehicle and as such, it is imperative that the tool being used here, is accurate and makes the designing process easy. The rubber bushing can be imagined to be a combination of a non-linear elastic spring, a frequency dependent Maxwell component and an amplitude dependent frictional element. In order to ease the design of the bushing properties, a reduced number of input properties are used to calculate the bushing properties internally. While trying to validate the force hysteresis loop obtained through the model with the measured data, it was seen that the accuracy was quite poor for the model when loading it with dynamic loads corresponding to amplitudes of0.2 mm and lower. The quasi-static loading and dynamic loading above 0.2 mm is shown to have a satisfactory accuracy when compared to the measured data
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