B. Subba Reddy

Indian Institute of Science (IISc) Bangalore India · High Voltage Lab Dept of Electrcical Engg & Interdisciplinary center for Energy Research

The leakage current which flows on the surface of dielectric rods under high voltage involves a series of events which include partial arcing, discharges and corona, these phenomenon are highly non-linear. These sequence of events render the leakage current signal to be very much chaotic. In the present work, the process of delay-embedding is emplo...

Strong electric field enhancements near both end fittings of the high-voltage polymeric outdoor insulator contribute to premature degradation and aging. Nonlinear resistive field grading composites offer a promising possibility to stress control and more competitive products, especially with the increasing power density and voltage levels. Recently...

The investigation pertains to the failure analysis of Fibre Reinforced Plastic rods used in overhead transmission line insulators using appropriate data acquisition and analysis. The leakage current data, over an experimental period is captured and time-frequency analysis is implemented for determining the in-service condition of the overhead trans...

Thermoelectric Devices operate as a Thermal Heat Pump using Electricity and involve Electrical and Thermal Domains. The Bond Graph Approach is a Multi Domain Modelling Methodology which can be used to model these devices. The Bond Graph Model for Thermoelectric Devices is developed and explained in this paper along with Validation Experimentally. F...

In the present investigation, the application of the modified Johnson converter on a thermoelectric module is described. The electrical voltage and current are the thermoelectric module’s input, and output is the temperature difference between two surfaces. If the reverse voltage is applied to the thermoelectric module, the temperature of the surfa...

Implementation of smart meters with replacing the traditional energy meters are increasing each day because of the possibility of two-way communication between the customer and the utility. The data from the smart meters provide an opportunity for utilities and the clients in maintaining the accurate database, the data will be useful to understand...

In the contemporary world, the share of AC loads is significant; however, the requirement of DC loads is rapidly increasing, particularly in household and industrial applications. The systems in which both the AC and DC loads are installed require a dual converter, acting as either a DC-DC converter or DC-AC converter. The usage of the dual convert...

With the need for Power Quality Improvement in Distribution System, the need to test the possible solutions for this dynamic problem increases. Although simulation tools are available, they do not give practical output and the knowledge gained from the design of a test setup is unparalleled. Hardware design not only improves the understanding, but...

The present investigation proposes a DC-DC converter that can act as a buck-boost converter with an extended range of gain. The conventional buck-boost converter provides a high gain around unity duty ratio; however, the inductor is shorted to the source resulting in capacitor discharge to the connected load. This problem is addressed in the propos...

The advantages of polymeric insulators over the age-old ceramic or glass insulators laid the foundation for large-scale usage in power transmission. However, insulators in the field need to be monitored continuously for the proper functioning of the power system. In this chapter, the authors have attempted to evaluate the performance of 110 kV poly...

A modular approach for DC circuit breaker (DCCB) is presented in the paper; a commutation circuit is used as a module to compensate for the fault current in the primary circuit. The present investigation deals with the circuitry, extending both voltage and current ratings for the overall breaker. A series combination of these modular commutation ci...

This paper proposes a Direct Current (DC) circuit breaker based on a coupled inductor capable of interrupting a short circuit current in a few hundreds of microseconds. It consists of five MOSFETs, a unipolar capacitor, a mechanical circuit breaker, an inductor, and a coupled inductor. The proposed topology is a hybrid circuit breaker that provides...

The tracking of power in Solar PV systems depends on controlling the voltage or current to the optimum level irrespective of changes in Solar Irradiation. There are two aspects of Maximum Power Point Tracking (MPPT), first is to control the voltage or current and second is to find the peak power with an algorithm. This work deals with both the aspe...

Energy Management Systems involve monitoring of loads, control, and providing recommendations to reduce demand or energy costs. Energy Disaggregation works on monitoring loads non-intrusively, by having a single smart meter at the entry point to perform the task with machine learning techniques. Training of the machine learning model is an importan...

Phosphoric acid digestion of carbonate generates CO2 for stable oxygen and clumped isotope analysis using gas source isotope ratio mass spectrometer. The initial step of digestion reaction is protonation of calcite while the product CO2 equilibrates with the system allowing further exchange of isotopes to various extents depending on the nature of...

Our country is witnessing rapid growth in AC and DC transmission. There is a growing demand for the converters, which can play a dual role of conversion from DC voltage level to another DC voltage level and DC voltage to AC voltage. The proposed investigation focuses on the converter or inverter system, which can be connected to both DC and AC load...

Polymeric or silicone rubber insulators are extensively used for high-voltage transmission by electrical utilities due to advantageous features like lightweight, better contamination performance, etc. The performance of silicone rubber insulators exposed to low temperature conditions with continuous application of electric stress is of utmost impor...

This paper presents a novel method of utilizing pixel saturation of digital images of corona discharges to assess the degradation of polymeric insulating samples. A total of 20 corona images with varying exposure time from 0.5 to 120 s are captured and the image pixel intensity along the reference line is obtained. It is observed that the profile o...

The cover image is based on the Research Article Fractionation of stable oxygen and clumped isotopes during acid digestion of calcite in the presence of an external direct current electric field by Sanchita Banerjee et al., https://doi.org/10.1002/rcm.8921.

Integration of solar photovoltaic (PV) with AC grid is gaining more popular in distributed generation. In future, DC grid is likely to play a major role in the distribution system. With this in view the present investigation highlights the integration of solar PV with DC grid. High gain non-isolated DC-DC converter is used to connect two solar PV p...

Rationale Phosphoric acid digestion of carbonate generates CO2 for stable oxygen and clumped isotope analysis using a gas source isotope ratio mass spectrometer. The initial step of digestion reaction is protonation of calcite while the product CO2 equilibrates with the system allowing further exchange of isotopes to various extents depending on th...

The failure mechanism of in-service fiber reinforced plastic (FRP) rod used in composite insulators is studied experimentally; the integrity of Electrical/Chemical Resistance (ECR) of glass fibers in an epoxy-resin matrix of FRP rod used in transmission composite insulator is the subject of study. FRP Rods are subjected to extreme conditions of agi...

The present investigation highlights simulation study performed considering the temporal transformation of the electric field from capacitive to resistive. The effect of uniform pollution, single dry-band, multiple dry-bands and non-uniform pollution are studied in detail. The simulation results indicate the effect of surface current can literally...

Due to insufficient literature on the performance of insulators for HVDC, multi-stress accelerated ageing study on composite insulators is envisaged, wherein the degradation mechanisms, long-term performance of insulators under HVDC experimental investigations are conducted. With the available literature and standards for ac stress, in the present...

Polymeric based Composite insulators are extensively used for overhead rail electric traction system; these insulators play an important role in the traction electrification which supply power to the locomotives of train. Traction insulators are subjected to a variety of stresses, like mechanical, electrical, environmental, etc., these stresses act...

Electric power demand is growing at an exponential rate due to establishment of industries and economic growth in the country. Central electricity authority of India (CEA) has estimated per capita electricity consumption will increase at 6 percent per annum, this will increase the load on the transmission and distribution system. Limitations of Rig...

Electric field computation under unipolar voltage is different from that under power frequency. The general boundary condition for dielectric interfaces includes equality of the tangential component of the electric field and the difference of the normal component of electrical flux density that is equal to the surface charge accumulated along the i...

Composite or polymeric insulators are being used in various parts of the world for high-voltage transmission and distribution lines. In some parts of India, places in the states like Rajasthan and Gujarat experience an increase in the daytime temperature up to 50 °C, while the nighttime temperature reduces as low as 3-5 °C. Because of these extreme...

Bulk molding compound (BMC) or Glass Reinforced plastic (GRP) composite insulators are extensively used for the third rail electric traction system. The performance of these insulators primarily depends on the local environmental conditions that cause degradation over a period of time. Degradation leads to partial arcing which grow more severe and...

In the present work, surface degradation studies are performed on silicone rubber based polymeric insulators using rotating wheel and dip test under DC voltage application. This work gains importance as number of HVDC lines are being constructed for transferring bulk power over long distances particularly in the country. A newly developed rotating...

Silicone rubber based polymeric insulators are being used widely used as outdoor insulation for high voltage applications. However, their long-term service life performance is highly dependent on local environmental conditions that cause deterioration of material properties of the insulators. In the present work, tracking and erosion studies are co...

Recently, we reported fracture of edge cracked thin metallic conductors upon passing only electric current, i.e., due to the self-induced electromagnetic forces. In this study, effect of simultaneous application of an electric current and a mechanical load on fracture of a thin edge-cracked conductor is investigated. Firstly, finite element method...

We investigated propagation of a sharp crack in a thin metallic conductor with an edge crack due to electric current induced electromagnetic forces. Finite element method (FEM) simulations showed mode I crack opening in the edge-cracked conductor due to the aforementioned (i.e., self-induced) electromagnetic forces. Mode I stress intensity factor d...

In the present investigation, long term service performance of silicone rubber based polymeric insulators under DC stress with controlled climatic conditions is attempted. Simultaneous application of UV, thermal, humidity with DC electrical stress is applied to polymeric insulators enclosed in a specially fabricated climatic chamber. The stresses a...

Polymeric insulators are emerging as popular outdoor insulation for high voltage applications. However, environmental stresses along with prolonged electric discharges cause degradation to the promising properties of polymeric insulators. In present work, an attempt has been made to fabricate the experimental facility, study the multiple stresses (...

This paper presents a single DC source fed fivelevel converter topology for medium voltage high power isolated grid-tied systems with reduced power switch count. The proposed converter generates two phase system of voltages that are further converted to three phases by using Scott-T transformer connection. Compared to existing topologies, the propo...

Currently there is a significant requirement for the electrical energy across the globe. Many countries including India are adopting ultra high voltage (UHV) AC and DC transmission. HVDC transmission is increasingly being adopted for long distance transmission for evacuating huge power transfer in comparison to UHVAC. The design of overhead transmi...

Assessment of the material degradation in laboratory similar to field conditions is still a challenge. In the present work an attempt is made to study the effect of environment conditions in service life of polymeric insulators on tracking and erosion resistance. Evaluation of tracking and erosion resistance of Silicone Rubber insulating samples of...

A novel single DC source fed five-level converter topology for medium voltage high power isolated grid-tied systems requiring only twelve power switches is proposed. The present configuration has two stages namely, five level converter and the Scott-T transformer. The five level converter stage generates only two phase voltages. Latter these voltag...

Voltage sag or voltage dips are significant to industrial reliability. There is a necessity to characterize the feeder level power quality (PQ) and the PQ performance among various utility companies. Contamination/pollution induced flashover is the ultimate consequence of the creeping discharges across the insulator strings which induce voltage sag...

This paper presents a novel single source fed isolated gate driver circuit based on the dual forward converter topology. The two forward converters are paralleled at the secondary side to achieve 0 - 100% duty cycle range together with galvanic isolation. The gate driver switching frequency is independent of the main pulse width modulation frequenc...

Accelerated aging experimental investigations are performed on polymeric insulators which are used for extra high voltage (EHV) and ultra high voltage (UHV) transmission. A newly developed rotating wheel and dip test facility as per std. IEC 62217 is used for the study. The experimental study is conducted with AC stress for 1500 cycles. The specime...

In recent times, high temperature vulcanized (HTV) silicone rubber (SIR) insulators featuring several advantages, have gained importance over conventional ceramic and glass insulators. However, environmental stresses and electrical discharge activities degrade their superior performance therefore long term reliability of polymeric insulators is sti...

In the present work, behavior of corona discharges on the polymeric insulating sample, generated from a multiple needle electrode in the presence of normal air and fog (mist) condition is studied with the aid of an image processing technique. The development of streamers is closely monitored using the high resolution digital single lens reflection...

Corona is considered to be an unavoidable event in high voltage transmission system. The effect of corona includes the generation of audio noise, radio interference, power loss etc., adding to the list, corona has been identified as a potential threat for the long term operation of high voltage polymeric insulators. Studies on the corona phenomena...

In recent times high temperature vulcanized (HTV) silicon rubber insulators (SIR) are being widely used for overhead high voltage transmission and distribution systems. However, over a period the insulator surface will be exposed to high temperature in several places particularly in desert areas, further accumulation of pollutants can alter the tem...

Digital image processing is being widely used in all fields of science and engineering, like the detection of cancer cells, identification of the soil properties etc. Application of image processing to high voltage phenomenon has not been well explored. The present work attempts to identify the possible application of image processing techniques to...

Presently there is a continuous demand for the electric power consumption across the globe, however with the existing distribution lines are reaching critical limits of ampacity and sag, it has become difficult in finding corridors to construct new overhead lines in many industrialized countries including India. Replacing the existing ACSR conducto...

For last few decades, high temperature vulcanized (HTV) silicone rubber (SIR) insulators are increasingly being accepted as outdoor insulation due to its advantages in comparison with porcelain or glass insulators. However, over a period of time, insulator is exposed to higher temperature in arid climates and deposition of contaminated substances o...

In recent times due to several advantages, high temperature vulcanized (HTV) silicon rubber insulators (SIR) are being widely used for overhead high voltage transmission and distribution systems. However, over a period the insulator surface is exposed to high temperature in several places including desert areas, further accumulation of pollutants c...

Polymeric insulators are used for high voltage transmission and distribution systems due to their advantages over traditional ceramic/glass insulators. However, these insulators encounter various stresses in the service condition. CIGRE working group D1.14 has identified twelve important parameters for the evaluation of polymeric outdoor insulation...

A rapid increase in electric power consumption is witnessed, there is a demand for the uninterrupted power supply. Newer generation units are being built with the increased installed power. The available transmission lines are reaching critical limits of ampacity and sag; hence there exists an intricacy in finding corridors particularly in densely...

Corona resulting from the metallic parts of the transmission line insulators and hardware has proven to be the potential factor in inducing the degradation of polymer insulators. Corona activity is found to increase substantially during the foul weather condition (rain, fog/mist, hoarfrost), which further promotes the ageing of polymer insulators....

In the recent years there has been a considerable increase in the demand for electrical power requirement across the globe. The transmission voltage levels have increased to 765 kV ac and ±800 kV dc. Further HVDC transmission is becoming increasingly viable as it is more economical for long distance transmission and can carry large amount of power...

Corona discharges resulting from the metal parts of insulators and the line hardware affect the long term performance of the polymeric insulators used for outdoor application and can lead to its eventual failure. The authors previous work, involved in developing a new methodology to evaluate the performance of polymeric shed materials subjected to...

Tracking and erosion is an important constraint for the long term evaluation of polymeric insulators used in high voltage transmission. In the present work, experiments are conducted on different polymer insulator samples; to evaluate these insulating samples a Recurrence plot (RP) analysis is adopted. The results of the recurrence plot analysis of...

Corona discharges from the insulator metal parts and the line hardware influence long term performance of the silicon rubber insulators used in HVAC and HVDC transmission. Polymeric insulators when installed are highly hydrophobic; they have to perform under various mechanical, electrical and environmental stresses, over a period the hydrophobic pr...