Insulation Resistance Value Research Articles

Identification of inter-turn insulation faults in induction motor

Purpose Induction motors (IMs) are considered one of the most important elements of the industrial process. However, in this environment, these machines are subject to electrical and mechanical faults, which may cause significant financial losses. Thus, the purpose of this paper is to propose an optimal identification of inter-turn insulation faults present in the random wound IM. Design/methodology/approach The design approach deals with a simple technique, using the effect of the inter-turn fault in modifying the high-frequency components of the applied pulse-width-modulated voltage. Findings The change in insulation strength between the turns affects the capacitive component of the stator line current. Resulting changes in wave shapes of the applied voltage have been studied with respect to both the distance of inter-turn faults from line end and reduction in the insulation strength, and hence in the insulation resistance value. Originality/value Studies have been conducted by using computer simulation and validated by experiments. There is ample evidence that an impending and progressing inter-turn fault can be identified in adjustable speed drives driven by frequency converters by studying line-end coil-voltage waveforms.

PROSES PERAKITAN DAN PENGUJIAN KUBIKEL SM6 VACUUM CIRCUIT BREAKER 20 kV DI PT. GALLEON CAHAYA INVESTAMA

At PT. Galleon Cahaya Investama which in this case much needed electrical appliance to be used in distribution network that is one tool of cubicles before marketed at other company. Cubiclesis a connecting device, divider and disconnecting load doing testing. In this cubicle insulation testing,cubicle is already in pairs and have connected with The transformer after that just done insulation testing with mega ohm meter, because cubicle is already 5 with the transformer then the insulation resistance value will be reduced because of the existing transformer windings in it. In testing leakage current PMT component is still in good condition, seen from test results that is still Below 300 μA, and in the test of isolation resistance, also in good condition, looking from the results that have been tested still shows the value above the standard isolation resistance. With visual inspection by looking at the results of work with the eyes and tools, namely see the shape, rust and placement of components that have been right.

Criteria of creating a multi-level system of electrical equipment diagnostics, control and protection

The reliability of the power electrical equipment (EE) of industrial enterprises, agriculture and medical institutions largely depends on the operating modes and power quality of the supply network. The existing methods of protecting EE, of an X-ray CT scanner, for example, act selectively and their actions are aimed at identifying and protecting electrical equipment from a certain type of a defect. This paper considers the criterion for creating a unified system of control, diagnostics and protection, which is – «EE + supply network» as a unified complex for controlling the switching modes of EE. The total volume of the system consists of five levels of protection types. The number of levels is determined by the type of EE and the magnitude of the possible estimated damage. The first level of protection is the diagnostics of the network state – the initial and subsequent continuous monitoring of the line voltages level and the rate of change of the front of the supply voltage first harmonic component. The second level is the diagnostics of the causes of the current-carrying lines breakage. The third level of protection is EE temperature protection and diagnostics of the thermal overloads causes. The third level is continuous monitoring of temperature indicators of EE. The fourth level is continuous monitoring of bolted connections temperature indicators. The fifth level is control of the insulation resistance value and diagnostics of the reasons for its decrease; moisture isolation protection; EE life prolongation, reliability and trouble-free work ensuring

Research on Intelligent Optimization Algorithm for the Hot Press Insulation of Generator Stator Bar

As the heart of generator, stator bar’s production quality will directly influence the whole generator’s quality. We researched heating and solidification process of stator bar at the beginning to clarify the relationship between heating time and temperature. BP neural network toolbox in MATLAB platform was used to build neural network model which will relatively accurate estimate bar’s resistance with four process parameters. Through the resistance, people can find out the best technological parameters before actually production. We used some data collected from one factory as learning data. Others were test data, used to illustrate the rationality of the model, which can forecast insulation resistance value in later production, finding the optimal process parameters.

Simulation analysis of the influence of leakage resistance on 1–10–100 TΩ guarded resistance transfer devices accuracy

Abstract Accuracy of high resistance transfer devices is very much dependent on insulation leakage. The subject of this paper is a digital analysis of the influence of insulation leakage on 1–10–100 TΩ guarded transfer device. The aim of this analysis is to minimize the errors of guarded resistance transfer devices caused by insulation leakage. The effects of the choice of the values of guarding resistors and their arrangement in the devices on transfer accuracy has been examined. Moreover, the influence of a decrease of the insulation resistance value was probed. The results of the research clearly indicate that a proper selection of guarding resistor values can improve the accuracy of the guarded transfer device. Also appropriate arrangement of the main and guarding resistors in transfer devices allows a decrease in errors of the transfer devices.

Dynamic parametric design and feasibility assessment for a high resistance measuring system

Abstract A high resistance measuring system (HRMS) is used to measure the surface insulation resistance (SIR) values of the printed circuit board (PCB), and monitor whether a momentary circuit short and/or the case of current slow leakage occur, which will affect the electrical properties of electronic components. This study constructs a dynamic parameter design for optimization of the test parameters of the HRMS in order to obtain robust test results. The optimal test parameters for SIR testing are: 390 ms test time, 100 V test voltage, 100 V, 15 s charge time, and 100 s pause interval. Further investigation is conducted on the impact of the test parameters on the measurement performance.

The Effect of Self-producing Heat and External Radiation on the Insulating Property of Wire

The effect of self-producing heat and external radiation on the insulating property of wire are studied experimentally in this paper. In the experiments of self-producing heat of wire, 6 types of wires are used under the situation of overloading. The results show that the effect of the temperature rise of wire on insulating property of wire is remarkable. Under the situation of having electric current wired to produce heat by itself, the insulation resistance of wire decreases and the leakage of electricity electric current enhances. Under the situation that electric current is relatively stable, the temperature becomes stable when rising to a certain value, conducting wire heat dissipating and fever heat are in an equilibrium state. In the experiments of external radiation, such as the situation of building fire, RV sheathed wires present a similar regulation to the self-producing heat experiments. The difference is that the effect of external factor (such as air flow, voltaic instability, etc.) on temperature of wire is more obvious than that on the insulation resistance of wire. When external factor makes the wire temperature decrease to a certain value, the insulation resistance value is higher than that out of the effect.

THE ABSORPTION CHARACTERISTICS OF THE PHASE AND ZONE PAPER-IMPREGNATED INSULATION OF POWER CABLE AT DIRECT VOLTAGE

Introduction. The moral and physical deterioration of medium voltage power cables with phase and zone paper-impregnated insulation requires implementation of quality systems and reliable nondestructive electric diagnostic. Informative indicator of the insulation is the time decay curve of the charging current. It reflects the processes of accumulation of space charges (absorption). The measurements are carried out the 15th since the second direct voltage supply, then – on the 30th and the second on the 60th second. The ratio of the parameters measured in these times gives the dimensionless criteria – absorption coefficients. Three measurements are made at different times, provide a more complete picture of the state of insulation than the measurement of the value of steady leakage (conduction-through), adopted in conventional prevention trials. Purpose. Research and testing methods of diagnostics of power cables with paper-impregnated insulation by absorption and phase characteristics of the belt insulation based on the total measurements. Methodology. A procedure for determining the individual characteristics of phase and zone paper-impregnated insulation based realized on the use of the equivalent circuit of a three-core cable in the metal shell and solved of an over determined system of linear algebraic equations by least squares. Results. The proposed method allows determining the absorption characteristics of the individual phase and zone insulation medium voltage power cables in the overall metal shell at a direct voltage. Individual characteristics reflect the characteristics of cables and allow a greater degree to assess the degree of aging of each of the components of paper-impregnated insulation. Originality. Regardless of the cable connection diagrams probing electric field grabs as the phase, and zone insulation. The cumulative nature of the measurement leads to the fact that the differences in the properties of insulation components are smoothed: the aggregate results of the measurements do not differ for the different schemes of the same type. The individual characteristics of isolation, defined on the basis of the proposed method are more differences than total, indicating that non-symmetrical modes of operation of the cable. Practical value. The values of individual characteristics power cables 6 kV are 3 times more total, because of what their direct measurement may be a problem. The total resistance of several insulation spaces connected in parallel, behind the individual. Smaller values of insulation resistance are measured more easily, especially on short samples cables.

절연저항 측정 장치에 의한 지락사고 전류의 비변화

Abstract With progress in industrialization, facilities for generating, delivering, and receiving high levels of electric power are in great demand. The scale of electric power equipment is increasing in both size and complexity. This has contributed to the development of our modern, high-tech and information-based society. However, if the generation of electric power is suspended due to unexpected accidents at power facilities or power stations, a range of equipment the operations of which are dependent on electric power can be damaged, causing substantial socioeconomic losses in an industrial society. A great deal of time and money would be expended to repair damaged facilities at a power station, causing enormous economic loss.In order to detect the deterioration processes of power cables, and to prevent the destruction of power cables, the operation status of power cables should be monitored on a regular basis. We have installed equipment at Korea Western Power Co., Ltd., located in Taean, in order to predict and prevent the destruction of power cables. This is an entirely new installation: a set of equipment invented specifically to measure the insulation resistance of power cables. Installation of the equipment does not cause the flow of earth fault current. This ensures accurate measurement of insulation resistance values by the equipment. We have been studying this equipment in order to develop preventive technology that would show the deterioration processes of power cables.

Influence of ambient and test conditions on insulation resistance/polarization index in hv electrical machines - a survey

Ambient and test conditions can affect the analysis results of the insulation system testing in high voltage (HV) electrical machines. In this context, insulation resistance (IR) and polarization index (PI) are two common techniques for winding insulation assessment in offline mode. This paper investigates the influence of main parameters that affects IR/PI tests results. Temperature, humidity, and pressure are the wellknown environmental parameters which could affect dielectric parameters of insulation such as IR and PI. On the other side, test voltage level and voltage polarities connections are two prominent factors in sampling the resistance during the test. Moreover, the insulation resistance value depends on the type of fault and its severity. The variations of insulation resistance with considering the mentioned parameters are evaluated in this paper, to study the possible correlation between IR/PI and changes in other parameters. It was found that with taking the effective parameters into account, the accurate and reliable insulation test interpretation can be achieved in HV electrical machines. A comprehensive review of literature was done and industry experts were surveyed for their ideas and experience under a research project. The main results are summarized in this paper.

Insulation Resistance Degradation in Ni–BaTiO3Multilayer Ceramic Capacitors

Insulation resistance (IR) degradation in Ni-BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> multilayer ceramic capacitors has been characterized by the measurement of both time to failure (TTF) and direct current leakage as a function of stress time under highly accelerated life test conditions. The measured leakage currenttime dependence data fit well to an exponential form, and a characteristic growth time τSD can be determined. A greater value of τSD represents a slower IR degradation process. Oxygen vacancy migration and localization at the grain boundary region results in the reduction of the Schottky barrier height and has been found to be the main reason for IR degradation in Ni-BaTiO3 capacitors. The reduction of barrier height as a function of time follows an exponential relation of φ(t) = φ(0)e <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2Kt</sup> , where the degradation rate constant K = K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> e(-E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</sub> /kT) is inversely proportional to the mean TTF (MTTF) and can be determined using an Arrhenius plot. For oxygen vacancy electromigration, a lower barrier height φ(0) will favor a slow IR degradation process, but a lower φ(0) will also promote electronic carrier conduction across the barrier and decrease the IR. As a result, a moderate barrier height φ(0) (and therefore a moderate IR value) with a longer MTTF (smaller degradation rate constant K) will result in a minimized IR degradation process and the most improved reliability in Ni-BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> multilayer ceramic capacitors.

High Voltage Security System Design and Testing of Electric Car

Safety design of high voltage part is the foundation of the whole automobile design; it is based on safety design requirements of the electric car, and the security function of hardware. The design the different functions of hardware modules are presented, through circuit principle diagram layout of PCB, and circuit board is made, the systems hardware test board is design according to the functional test of the system. Test results show that relative errors between the measurement of insulation resistance value of the safety system and the theoretical value is only 0.3%, thus the rationality of the design calculation model of the insulation resistance is verified. The response times of DC (direct current) contactor are higher than the national standard requirements, so the system security design meets the design requirements. DOI : http://dx.doi.org/10.11591/telkomnika.v12i5.4899

Design of Side Line Short Circuit Detection Device Load of Low Voltage Circuit Breaker before Closing

It uses MSP430F2274, the ultra low power microcontroller, as the control core of short circuit detection device, through the accurate measurement of low voltage circuit breaker load side of the main wiring of insulation resistance value and the interphase insulation resistance value, outputting high voltage startup sound and light alarm device, and then accomplish the open circuit fault detection. Testing power supply is the use of magnetic coupling resonance principle, from the main power grid electrical insulation for short circuit detection device. The device has the advantages of low cost, small volume, good safety, good detection effect, and can be embedded in use in low voltage circuit breaker.

Research of Airfield Lighting Insulation Resistance Prediction Based on Gray System Theory

Airfield lighting circuit is an important part of airfield lighting system, and the insulation resistance value of this circuit is affected by humidity, temperature, the quality and the number of the Isolation Transformers and many other factors, so it is difficult to accurately predict the resistance size by using traditional methods. In the light of insulation resistance values of airfield lighting circuit, this paper put forward adopting Gray System Theory to make the prediction, and then build GM(2,1) model to analyze and forecast the resistance values according to the actually measured values of the insulation resistance at Shanghai Pudong International Airport. Finally, the research shows that there is only a little difference between predicted values and the actually measured values. In other words, the prediction of insulation resistance based on Gray System Theory is viable.

Design and application of GDC on EAST Tokamak

On EAST Tokamak, DC glow discharge (GDC) is developed to clean the first wall of plasma. It can effectively control the recycling of H, C, O impurities and improve the wall conditions. There are four GDCs which distribute equally on the EAST Tokamak vacuum vessel wall. Each GDC is equipped with an anode, a stainless steel cover and four support legs. The anode is insulated from cover with Al 2O 3 ceramics. After a round of experiment, the value of insulation resistance of GDC decreases remarkably due to metallization. To protect the insulation parts and heighten the reliability, ceramic protection covers are used on the GDCs. The other measures which can heighten insulation grades are also taken. After upgrade, the insulation resistance of each GDC between anode and ground is raised highly. When the pressure reaches 4 Pa, H 2-GDC and He-GDC is strarted. Boronation and siliconization are also applied to the device wall conditioning. After GDC cleaning, the impurities and partial pressure of remainder gases in vacuum vessel (VV) is decreased greatly and vacuum degree of VV can reach high easily.

Thermal response simulation for tuning PID controllers in a 1016 mm guarded hot plate apparatus

A mathematical model has been developed and used to simulate the controlled thermal performance of a large guarded hot-plate apparatus. This highly specialized apparatus comprises three interdependent components whose temperatures are closely controlled in order to measure the thermal conductivity of insulation materials. The simulation model was used to investigate control strategies and derive controller gain parameters that are directly transferable to the actual instrument. The simulations take orders-of-magnitude less time to carry out when compared to traditional tuning methods based on operating the actual apparatus. The control system consists primarily of a PC-based PID control algorithm that regulates the output voltage of programmable power amplifiers. Feedback parameters in the form of controller gains are required for the three heating circuits. An objective is to determine an improved set of gains that meet temperature control criteria for testing insulation materials of interest. The analytical model is based on aggregated thermal capacity representations of the primary components and includes the same control algorithm as used in the actual hot-plate apparatus. The model, accounting for both thermal characteristics and temperature control, was validated by comparisons with test data. The tuning methodology used with the simulation model is described and results are presented. The resulting control algorithm and gain parameters have been used in the actual apparatus without modification during several years of testing materials over wide ranges of thermal conductivity, thickness, and insulation resistance values.

Effect of posture positions on the evaporative resistance and thermal insulation of clothing

Evaporative resistance and thermal insulation of clothing are important parameters in the design and engineering of thermal environments and functional clothing. Past work on the measurement of evaporative resistance of clothing was, however, limited to the standing posture with or without body motion. Information on the evaporative resistance of clothing when the wearer is in a sedentary or supine posture and how it is related to that when the wearer is in a standing posture is lacking. This paper presents original data on the effect of postures on the evaporative resistance of clothing, thermal insulation and permeability index, based on the measurements under three postures, viz. standing, sedentary and supine, using the sweating fabric manikin-Walter. Regression models are also established to relate the evaporative resistance and thermal insulation of clothing under sedentary and supine postures to those under the standing posture. The study further shows that the apparent evaporated resistances of standing and sedentary postures measured in the non-isothermal condition are much lower than those in the isothermal condition. The apparent evaporative resistances measured using the mass loss method are generally lower than those measured using the heat loss method due to moisture absorption or condensation within clothing. Statement of Relevance: The thermal insulation and evaporative resistance values of clothing ensembles under different postures are essential data for the ergonomics design of thermal environments (e.g. indoors or a vehicle's interior environment) and functional clothing. They are also necessary for the prediction of thermal comfort or duration of exposure in different environmental conditions.

컨버터 내장형 LED 가로등 및 보안등의 전기적 특성 분석

In this paper, we studied electrical characteristics of internal converter type of LED lamps for road and street lighting. We surveyed electro-technical regulations and KS(Korean industrial standards) about LED luminairs. Waveforms of voltage and current, thermal distributions, insulation resistances between live parts and exposed conductive parts, and flame test of cover of LED lamps were experimented and analyzed. In regulations, insulation resistance between live conductors and exposed conductive parts should be greater than 0.2㏁ in case nominal voltage of wiring is 220V. In KS codes, the value of insulation resistance should be greater than 2㏁ while applying DC 500V or DC 100V. In the result of this study, waveforms of primary voltage and current were distorted. There was difference in waveforms of secondary voltage and current according to composition of converter. Mostly, insulation resistances were measured high more than regulation and code value but some measured points were measured badly(0.0㏁). Cover of LED lamps was ignited easily. We expect that the results of this study would be helpful for revision of regulations and national codes for the electrical safety of LED road and street lighting.

고용량 적층 세라믹 커패시터에서 설계 및 제조공정에 따른 전기적 특성 평가

The purpose of this work was to investigate the design and fabrication process effects on electrical properties in high capacitance multilayer ceramic capacitor (MLCC) with nickel electrode. Dielectric breakdown voltage and insulation resistance value were decreased with increasing stack layer number, but dielectric constant and capacitance were increased. With increasing green sheet thickness, dielectric breakdown voltage, C-V and I-V properties were also increased. The major reasons of the effects were thought to be the defects generated extrinsically during fabrication process and interfacial reactions formed between nickel electrode and dielectric layer. These investigations clearly showed the influence of both green sheet thick ness and stack layer number on the electrical properties in fabricating the MLCC.

Noise thermometry in crystal growth facilities for the International Space Station (ISS)

AbstractAlthough noise thermometry is an established technique for absolute temperature measurement, several aspects needed to be clarified before this method can be employed for temperature measurement in a space furnace at 1800°C. First, the electrical insulation resistance for sheathed sensors with different insulation materials were measured. Five test sensors with outer diameters of 3.2 mm or less were fabricated and tested. The measurements clearly show a significant advantage for the pyrolytic boron nitride (pBN) insulation compared to Hafnium oxide. The electrical insulation resistance values at 1800°C for the sensors with HfO2 were below 10 Ω, whereas pBN‐insulated test sensors exhibited values of more than 600 Ω for the same diameter. Furthermore, no difference has been found between the resistance of bent and straight sensors. Based on these results a miniaturised and bent noise thermometer with a diameter of 3.2 mm having a pBN insulation was fabricated. This sensor and additional control thermocouples were subjected to performance tests up to 1800°C in a space‐compatible furnace. All sensor readings exhibited a consistent figure during the tests. The noise thermometer, however, showed always the highest reading indicating that noise thermometry is an appropriate method for accurate measurements of absolute temperatures, even in the harsh environment of a compact multi‐zone space furnace.