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Electrical energy is a primary need to supply all aspects of community needs andactivities for electricity. For this reason, maintenance is carried out to improve efficiency, quality, and distribution of electrical power. The PMT at thesubstations is used as a mechanical switch or as a circuit breaker. The methodused in this study was qualitative and quantitative to determine the presence of anomalies in electrical distribution. Based on in service/visual inspection, the condition of the equipment is good visually, and there is no anomalies were found. Testing at an insulation resistance, the rise and fall of the measurement results can be caused by several factors such as the wrong position of the measuring instrument, a dirty insulator body, or high humidity levels.

Introduction. Electrical insulation systems make up about 0.03 % of the traction electric machines (TEM) mass, but they are of exceptional importance and affect the design capabilities and manufacturing techniques of electric machines, ultimately - on their specific weight and overall dimensions, on the reliability and durability of the TEM. Purpose. The monitoring of the stability of the manufacturing process of electrical insulating systems of the TEM based on the insulation resistance measurements. Methodology. The analysis of the manufacturing process is carried out for three versions of the case of insulation of the magnetic system of the DC traction electric motor. Practical value. Construction and analysis of special graphs (charts) of individual values and cumulative sums of insulation resistance, sliding range MR allow to find out whether the technological process of manufacturing electric insulating systems of traction electric machines is in a statistically controllable state., Показано, что сопротивление изоляции может служить информативным параметром стабильности технологического процесса изготовления электроизоляционных систем тяговых электрических машин. Установлено, что сопротивление изоляции находится в пределах ±3σ относительно среднего значения каждой выборки трех вариантов исполнения электроизоляционной системы. Представлены контрольные карты индивидуальных значений и кумулятивных сумм сопротивления изоляции магнитной системы тяговых электродвигателей постоянного тока.

The insulation resistance of conventional atmospheric plasma-sprayed alumina coatings with 10–15% porosity is ∼1011 Ω. The presence of pores, lamellae boundaries, and other non-fillings dampens the...

The article deals with the possibility to create the cement-based material with improved electrophysical characteristics. The material can be used in the rail sleeper production, which will improve the insulation resistance of track circuits and increase transportation reliability. Besides, various kinds of structures made of it, e.g. foundations, piles, supports, bridges and tunnels, will decrease the impact from leakage and stray currents leading to intensification of electrocorrosion processes in railway structures, and will increase life cycle of the structures. It has been experimentally established that addition of bitumen emulsion to the cement and sand grout increases electrical resistance 4 times in the test samples in comparison with a check sample without additives. Insignificant increase in the setting-up time can be eliminated with early-strength admixtures or by the concrete steam treatment traditionally applied at concrete product plants.

阐述了绝缘电阻的定义及重要性；分析了测量方法对绝缘电阻测量结果的影响；建立了绝缘电阻测量不确定数学模型，并确定了不确定分量的灵敏度系数。测量了BV线的绝缘电阻，并确定了不确定分量的评定方法，计算得到测量扩展不确定度。最后提出了测量绝缘电阻的建议。 The importance and definition of insulation resistance were discussed. The influence produced by measurement method was analyzed. The mathematical model was built, and sensitivity coefficient of uncertainty components was determined. Insulation resistance of wires with the model BV was measured, and evaluation method of uncertainty components was determined, and expanded uncertainty was obtained. Proposal for measurement of insulation resistance was presented.

De-trapped charge dislodged from interfacial region of oil-paper insulation can be used as an effective insulation sensitive parameter. Over time, various physiochemical reactions takes place at interfacial region and consequently results in the formation of different trap sites (deep and shallow). Charges which resides at these traps sites are de- trapped after gaining sufficient energy. In present analysis, it is found that charge dislocated from deep traps maintains some specific type of relationship with different insulation sensitive parameters. Before using de-trapped (dislodge from deep traps) as an effective insulation sensitive parameter the effect of geometry must be reduced, as amount of de-trapped charge depends on the area of interfacial region which is not identical for all units. Result presented in this paper shows that use of geometric capacitance for normalization purposes significantly reduces the effects of insulation physical dimensions on de- trapped charge. The capability of deep charge (normalized using dc insulation resistance and geometrical capacitance) is also compared in the present work.

This paper presents an electrical performance testing of AC motors by measuring the Insulation Resistance Measurement, Polarization Index Measurement, Winding Resistance Measurement and Surge Comparison Measurement according to IEEE standards. The test results indicate that the efficiency of the motor. It can be developed into software and also be applied for practical work.

Operational direct current grids (ODCG) are one of the most important components of many power plants and substations, for example, hydroelectric power plants. They are designed for power supply of relay protection devices, signalization and automation, and for the power supply of important equipment, emergency lighting, drives of highvoltage switches, etc. The importance of this type of equipment leads to high-reliability demands of the ODCG. Quality of cable insulation of the ODCG is crucial. The research conducted in this field shows that both gradual and sudden short-term insulation resistance fluctuations depend on many factors. Among them are the mode of operation, network load, state of cable channels, and state of switching equipment. The results of five-year observations on insulation resistance of open distribution unit ODU-110/330 kV Dniester HPP-1, an distribution unit of DU-35 kV HPP-2 and a complete distribution unit CDU-330 kV of a pumping station in 2012–2017 are analyzed.

LH4-1 oil field is a subsea tie-back which was developed by CNOOC in 2012. After a short period of production, the subsea control umbilical started with low Insulation Resistance (IR) of its electric control quads. Extensive trouble shooting work immediately started. The trouble was identified to be on the main umbilical. The subsea electric control was swapped to the spare quad. After about a year, the spare quad also had zero IR. In order to resume the subsea control, feasibility of using the spare Medium Voltage (MV) power cable triads as control channel was studied immediately. The idea of using three core triad to establish dual communication channels with two frequency bands was thoroughly studied and it was found theoretically feasible. Originally the communication was one loop controls 4 wells, now with the new arrangement one loop controls 8 wells, 3-core with one as common return makes two loops. So the new MV cable communication configuration can still achieve subsea control with 100% redundancy. Subsea special bridge flyleads were designed and manufactured to convert the 70mm2 3-core MV flylead to 10mm2 4-core communication flylead. Offshore intervention work was done in 2014. After installation, subsea communication to all 8 wells was re-established as expected. The signal qualitywas much better that the original umbilical possibility due to the large MV copper cores.

The insulation degradation of a voltage transformer winding is not easy to find, but it may ultimately cause the transformer to explode, leading to accidents such as phase-to-phase short circuits. At present, power transformers, lightning arresters, and other equipment have on-line methods to detect the insulation state. However, there is no mature method for the on-line monitoring of voltage transformer winding insulation. In this study, a small current disturbance method based on a zero-sequence loop is proposed. The characteristic parameters of the low-frequency oscillation of zero-sequence voltage after a disturbance are used to evaluate the insulation state of the winding and detect faults. Theoretical modeling, simulation tests, and field tests show that when the insulation resistance of the voltage transformer winding is in the range 0&ndash, 40 k&Omega, a low frequency oscillation of about 10 Hz can be detected on the zero-sequence voltage, and its amplitude and duration are proportional to the degree of damage to the insulation. This can hence be used as a criterion for the on-line detection of voltage transformer winding insulation defects.

In this paper, the authors discuss the crucial aspects of the insulation resistance testing of PV installations. This test verifies the integrity of wiring systems, and can be used to detect or prevent damages to wiring and ground faults. The insulation resistance test measures the resistance between ungrounded circuits and ground, under the application of high-voltage. Baseline insulation resistance can be compared to measurements over time to assess degradation of PV arrays or conductors. This test is worldwide accepted as a crucial element of commissioning, and acceptance, and is governed by several technical standards. In this paper, the authors critically discuss technical issues related to the insulation resistance test, which can be challenging in large PV systems, and the correct application of standards. In addition, a case study is presented, which includes the results of insulation measurements performed on a 4.9 MWp free-field grid-connected PV installation, located in Southern Italy, whose operation was affected by continuous insulation failures.

Изоляторы воздушных линий электропередач играют важную роль в обеспечении транзита электрической энергии к потребителям. Правильный выбор и грамотный подход к диагностике и контроля электрических параметров изоляционных конструкций воздушных линий электропередач это залог эффективной и безаварийной работе сети. В данной статье проанализированы работы зарубежных авторов [1, 2] по методу косвенного измерения длинны пути утечки в изоляторах воздушных линий электропередач, а также разработанного алгоритма по диагностике распределения напряжения и сопротивления гирлянд изоляторов, в средах с высоким уровнем загрязнения атмосферы, для дальнейшего обнаружения неисправных изоляторов. В работе рассмотрены методы диагностики изоляционных конструкций воздушных линий электропередач. Данные методы направлены на обеспечение повышения эффективного использования линий электропередач. Применяя метод оценки состояния изоляции согласно [2], можно на ранних стадиях развития дефекта изоляции предотвратить аварийное отключение линий электропередач. Полученные коллегами их Китая результаты измерений распределения напряжения по длине гирлянды изоляторов, вызывают интерес, поскольку все исследования подобных распределений дают несколько иные результаты. Определить достоверность данных приведённых в статье по ее материалам практически невозможно. По нашему мнению, такие результаты могут быть обусловлены методом измерения распределения напряжения по длине гирлянды изоляторов и сложностью определения момента определения приложенного напряжения. Если принять полученные в статье результаты за истину, то применяя методы диагностики [1, 2] к расчетам потерь энергии в изоляционных конструкциях, можно более точно произвести вычисления токов утечки по поверхности изоляторов в зависимости от степени загрязненности атмосферы и погодных условий при достоверном распределения напряжения и сопротивления изоляции гирлянд изоляторов. Overhead power line insulators play an important role in ensuring the transit of electrical energy to consumers. The right choice and competent approach to the diagnosis and control of the electrical parameters of the insulating structures of overhead power lines is the key to effective and trouble-free operation of the network. In this article analyzes the works of foreign authors [1, 2] by the method of indirectly measuring the creepage distance in insulators of overhead power lines, as well as the developed algorithm for diagnosing the distribution of voltage and resistance of insulator strings in environments with a high level of atmospheric pollution, for further detection of malfunctioning insulators. The paper discusses methods for the diagnosis of insulating structures of overhead power lines. These methods are aimed at ensuring increased effective use of power lines. Using the method of assessing the state of insulation according to [2], it is possible to prevent an emergency shutdown of power lines in the early stages of the development of an insulation defect. The results of measurements of the distribution of voltage along the length of a string of insulators obtained by colleagues in China are of interest, since all studies of such distributions give somewhat different results. It is almost impossible to determine the reliability of the data given in the article on its materials. In our opinion, such results may be due to the method of measuring the voltage distribution along the length of the string of insulators and the difficulty in determining the moment of determining the applied voltage. If we accept the results obtained in the article as true, then applying the diagnostic methods [1, 2] to the calculation of energy losses in insulating structures, we can more accurately calculate the leakage currents on the surface of insulators depending on the degree of pollution of the atmosphere and weather conditions with a reliable voltage distribution and insulation resistance of garlands of insulators.

В данной работе подробно рассмотрен частный случай замера сопротивления изоляции на конкретном объекте, рассмотрены пошагово действия от начала замеров до его окончания. Отдельное внимание уделено Ñ‚ÐµÑ Ð½Ð¸ÐºÐµ безопасности при работе с высокоточным оборудованием и Ñ‚ÐµÑ Ð½Ð¸ÐºÐµ безопасности в процессе снятия показаний. На ÑÑ ÐµÐ¼Ð°Ñ Ñ€Ð°ÑÑÐ¼Ð¾Ñ‚Ñ€ÐµÐ½Ñ‹ структуры Ñ€Ð°Ð·Ð»Ð¸Ñ‡Ð½Ñ‹Ñ Ð²Ð¸Ð´Ð¾Ð² кабелей. Изучены значения и область применения Ñ‚ÐµÑ Ð½Ð¸Ñ‡ÐµÑÐºÐ¾Ð¹, нормативной и регламентируемой документации в Ð¿Ñ€Ð¾ÐµÐºÑ‚Ð°Ñ ÑÐ»ÐµÐºÑ‚Ñ€Ð¸Ñ‡ÐµÑÐºÐ¸Ñ ÑÐµÑ‚ÐµÐ¹. Указаны ÑÑ ÐµÐ¼Ñ‹ Ð¿Ñ€Ð¾Ð´ÐµÐ»Ð°Ð½Ð½Ñ‹Ñ Ñ€Ð°Ð±Ð¾Ñ‚., In this paper, a special case of measuring the insulation resistance on a particular object is considered in detail, the step-by-step actions from the beginning of measurements to its end are considered. Special attention is paid to safety when working with high-precision equipment and safety in the process of taking readings. The structures of different types of cables are considered in the diagrams. The values and scope of technical, regulatory and regulatory documentation in the projects of electrical networks are studied. Schemes of the work performed are indicated.

The article provides an analysis of the properties of the working environment of submersible electrical equipment. The influence of the operating parameters of electrical equipment on the physical properties of the fluid (its electrically conductive properties) is considered. Mathematical confirmation of the implementation of electroosmosis in the capillaries of the insulation of submersible electric motors is given. The rationale for the active method of protecting submersible electrical equipment from reducing insulation resistance and preventing electrical breakdown is given.

Diferentes ensayos complementarios se implementaron sobre muestras de aisladores cerámicos sin y con defecto visual (suspensión, poste y buje) que operan en el nivel de tensión de 33 kV del operador de red CHEC S.A E.S.P, para conocer su grado de afectación después de haber sido sometidas a diferentes tensiones aplicadas (tensiones no disruptivas y flameo). Durante los ensayos de tensión, se realizaron lecturas simultáneas de: corriente de fuga, termografía y ultrasonido, las cuales fueron complementadas con pruebas de resistencia de aislamiento y factor de pérdidas ó tangente delta, antes y después de los ensayos de tensión. Las variaciones de éstas últimas complementadas con las lecturas simultáneas, permitió clasificar el aislamiento de acuerdo con su grado de afectación. Por último se realizó el procesamiento de las señales acústicas en condición de corona audible y flameo con la transformada wavelet. Los resultados confirmaron que el fenómeno de corona audible no solo se concentra en las bajas frecuencias del espectro acústico, sino, que los aislamientos que presentaron la mayor afectación después de los ensayos de tensión, mostraron los más altos contenidos de energía porcentual de su emisión acústica en baja frecuencia. Esto permitió clasificar el aislamiento de acuerdo con su energía acústica y compararlo con sus pruebas complementarias, observando una coincidencia del 100 % para ambas clasificaciones del aislamiento Abstract: Diverse complementary tests were undertaken on the ceramic insulator samples with and without visual defect (suspension, line post and bushing) that belong to the Local Energy Distribution CHEC S.A E.S.P and that operate at a voltage of 33 kV. These tests were performed with the aim to identify the affectation level in ceramic insulators after having been exposed to different withstand voltages (non-disruptive voltages and low-frequency dry flashover). During the high-voltage assessment, simultaneous measures were taken: leakage current, infrared imaging and ultrasound, which were complemented with other tests such as insulation resistance and losses factor or dissipation before and after the high-voltage testing. The variations on the findings of both tests allowed the classification of the insulation according to its affectation level. Along with the procedures aforementioned, the processing of acoustic signals in condition of audible corona and low-frequency dry flashover with the wavelet transform was implemented. The results yielded that not only does the phenomenon of audible corona concentrate on low frequencies of the acoustic spectrum, but also that the insulations with the major affectation levels showed the highest content of the porcentual energy of their acoustic emission in low frequency. This issue allowed the classification of insulation based upon its acoustic energy and the comparison to its complementary tests. A coincidence of 100% was observed in both classifications Maestría

Improving the fire resistance of the key cables connected to firefighting and safety equipment is of great importance. Based on the engineering practice of an oil storage company, this study proposes a modification scheme that entails spraying fire-retardant coatings on the outer surface of a cable tray to delay the failure times of the cables in the tray. To verify the effect, 12 specimens were processed using five kinds of fire-retardant coatings and two kinds of fire-resistant cotton to coat the cable tray. The specimens were installed in the vertical fire resistance test furnace. For the ISO 834 standard fire condition, a fire resistance test was carried out on the specimens. The data for the surface temperature and the insulation resistance of the cables in trays were collected, and the fireproof effect was analyzed. The results showed that compared with the control group, the failure time of the cable could be delayed by 1.57–14.86 times, and the thicker the fire-retardant coatings were, the better the fireproof effect was. In general, the fire protection effect of the fire-retardant coating was better than that of the fire-resistant cotton.

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.

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.

Purpose. The article deals with the insulation resistance of the track circuit as one of the parameters that affect the operating performance of the railway transport. To reduce the influence of the insulation resistance on the operation modes of the track circuits and the performance indicators of railway transport it is assumed to study the influence of crushed stone treatment on the value of dielectric permeability of the ballast bed. Methodology. The influence of material type for the surface treatment of crushed stone on the value of the dielectric permeability was assessed on the basis of the physical nature determination of the relative dielectric permeability. Determination of the relative dielectric permeability of granular media can only be indirect, as a consequence of incomplete adjoining of crushed stone grains and uncertainty of the pore volume. Thus, the calculations were performed by comparing the measured capacity for a medium with the known with measured medium capacity, for which it is necessary to define. That is, the more the measured capacity is changed, the more changes the dielectric permeability of the medium. Findings. Sleepers and ballast significantly change their electrical conductivity depending on the presence of moisture, ambient temperature changes, the presence of pollutants and other factors. The article analyzes the existing models to describe the dielectric properties of such systems. It has been established that coating the crushed stone ballast with organic substances influences the value of its relative dielectric permeability. The greatest effect of reducing this value is observed for the coatings based on rosin mixture and silicone. Originality . Authors proposed original method of dielectric properties increase of the permanent way by grains’ coating with nonwettable substances, on the surface of which is not formed a water film. Practical value . The article shows the possibility of minimizing the negative influence of reducing the isolation with maximum its elimination. It is proposed the solution of actual problem by eliminating the influence of insulation resistance on the modes of track circuits operation, which will eliminate the part of causes of the failure of signaling devices and reduce the number of cases of «false business».

Thailand is located in the tropical zone dominated by monsoons for more than six months in a year. These climatic conditions illustrate elevated relative humidity and temperature that contributes to Potential Induced Degradation (PID). Humidity has been reported to be potential cause of degradation in the systems with high voltages. Moisture helps leakage currents in passing through laminate permeation and back sheet from cell to ground frame. The PID occure in PV systems when connected in series using DC voltages of high orders. This research shows comparisons of both PV systems, with negative grounding and floating grounding with a system voltage about 800 Vdc. Investigations of insulation resistance (MΩ) in PV strings and modules after two years operation has been done. It was found that the decrement in average insulation resistance (MΩ) of PV string using negative grounding, floating grounding was 14.5 MΩ, 11.0 MΩ and average leakage current per string was 68.9 µA, 90.9 µA respectively. Moreover, the wet leakage current per module showed the decrement in average insulation resistance (MΩ.m2) was 174 MΩ.m2, 133 MΩ.m2 and average leakage current per module was 5.75 µA, 7.51 µA respectively.

Test results for a range of potting materials for encapsulation of wire bonds for a high temperature multi-chip module is presented. The potting materials include gels and more rigid epoxies, silicone, and silicone-ceramic materials. The materials were initially screened based on ease of processing, cracking, and weight loss at 200, 225, and 250°C. Materials that performed well after this initial screening were tested for insulation resistance at 200, 225, and 250°C and wire bonds were encapsulated for thermal cycled at −55 to 200°C and −55 to 250°C.

This paper presents the investigated variations in insulation resistances of amorphous silicon (a-Si), multi crystalline silicon (MC-Si) and hybrid solar cell (HIT). The insulation resistance of PV string of each system was measured and used to represent leakage current in photovoltaic system and the analysis was done in accordance with IEC 61215 Standard. The 10.152 kW multi-PV cell technologies grid connected system supports the energy demand of the 10 kW Building at School of Renewable Energy Technology (SERT), Naresuan University since July 2005 till date. In general the system was found effectively working under hot and humid climatic conditions of Thailand for a long duration. However the decrement in insulation resistance (MΩ) of a-Si string, MC-Si string and HIT string have affected electrical parameter of each system. The decrements in fill factor (F.F) over the 10 years period (July 13, 2005 – January 25, 2015) of a-Si, MC-Si and HIT were-27.4%, -21.9% and-6.2% respectively.

The article presents a computer simulation of absorption currents in dielectrics. The results of the study of changes in the absorption currents in time, as well as accelerated measurement of the insulation resistance taking into account the absorption current, are considered. When measuring the insulation resistance of electric power facilities, the absorption current which flows through the insulation and drops to zero in a very long time may initially exceed the leakage current. The article analyzes various patterns of representing the absorption current and proposes a new formula containing exponential and power functions. An approach is proposed for accelerated measurement of insulation resistance using extrapolation of absorption currents, that is, the calculation of the value (forecast) of the steady-state current in the measuring circuit, without waiting for the end of the absorption current flow and transients.