Power Research - A Journal of CPRI

Failure Analysis on OPGW Cable During Short Circuit Test

T. Prabakaran, Sumbul Munshi, Himangshu Roy, Saumitra Pathak — Fri, 01 Mar 2024 00:00:00 +0000

A new type of ground wire used for communication lines in high-voltage power transmission systems is called Optical Ground Wire cable (OPGW). In addition to serving as a communication optical cable and standard overhead ground wire, it may also prevent lightning strikes and carry short circuit currents. The OPGW cable must fulfil the specifications for both construction and performance for the ground wire to work, the optical fiber integrity, and the optical transmission characteristics to be appropriate for the intended use. It is anticipated that OPGW cables will safeguard the optical fiber and that the cable’s temperature won’t rise to the point where the fiber’s parameters could deteriorate. This paper examines the analysis and review of OPGW cable failure cases during short circuit tests.

Introduction to Topology Optimization for the Design of High Voltage Insulators

Balaji Sriram, Harivinay Varadaraju, Nandini Gupta — Fri, 01 Mar 2024 00:00:00 +0000

High Voltage insulators play a vital role in power transmission systems and are subjected to combined electrical, mechanical, and thermal stress. Common design strategies for HV insulators involve semi-analytical methods and Finite Element Analyses (FEA) to arrive at designs that meet the required design and manufacturing criteria. Topology Optimization (TO) is a design strategy widely adopted to minimize the weight and volume of the design while retaining its performance. In this work, we propose a modification to the traditional TO process to maximize the combined electrical and structural performance of HV insulators. This modification incorporates electric field considerations into the T.O. process.

Study on Advancements in Dielectric Testing in High Voltage Applications and Assessment of Effects of Ageing on Dielectric Properties

Ankit Vijay, Gaurav Savla, Gagan Kishore Nand, B. R. Pattanaik — Fri, 01 Mar 2024 00:00:00 +0000

The reliability of a power system relies heavily on the performance of insulation or dielectric materials used in various equipment like power cables, transformers, generators, switch gears, capacitors, reactors, and arresters. However, dielectrics can degrade over time due to various factors, including electrical stress, temperature, humidity, and other environmental conditions. The degradation or failure of insulation can lead to equipment malfunction, power outages, or even a catastrophic failure. Therefore, a periodic assessment and monitoring of insulation health and integrity through proper dielectric testing mechanisms serves as an essential tool for the safe and sustainable operation of an electrical power system. This paper also addresses the development of aging models and predictive tools for assessing the remaining life of dielectric materials in high-voltage applications, valuable insights into the long-term performance and reliability of dielectrics, enabling improved maintenance strategies and design guidelines for high-voltage systems.

Novel Halbach Permanent Magnet Solenoid Design using Finite Element Method

P. Trivedi — Fri, 01 Mar 2024 00:00:00 +0000

To generate the high axial field usually Electromagnetic Coils solenoid is used but it consumes large DC power supplies and cooling system and is not compact. The PM (Permanent Magnet) solenoid on the contrary can give fixed axial field profiles that are very compact and do not require any energy source as they are themselves energy sources. PM solenoids are usually designed using large radial and axial magnetized magnets. The drawback of such a design is using large radial magnets which are often unavailable with assembly problems. The paper discusses the novel Halbach solenoid configuration design and uses ref1 solenoid results to verify it. The finite element magneto static method is used to analyze the two models. The FEM magneto static analysis was done in Magnet Infolytica FEM magneto static analysis package.

Utilization of Capacitor Bank for Electromagnetic Pulse Crimping

Naushad Ali, Surender Kumar Sharma, Abhishek Lanje, Archana Sharma — Fri, 01 Mar 2024 00:00:00 +0000

Capacitors play an important role in an electrical system. They have numerous applications in the field of lasers, fast X-ray, neutron sources, electromagnetic pulse generators, electron beam accelerators, plasma generation and electromagnetic welding of materials. One of the applications of high voltage capacitors as energy storage and discharge devices is in the crimping of cables using the electromagnetic pulse forming technique. This research paper investigates the use of a high-voltage energy storage capacitor with a capacitance of 208 microfarads and rated voltage of 44 kV to perform Electromagnetic Pulse Crimping (EMPC) of lugs for 70 mm² and 120 mm² cables. The capacitor operates at 12 kV and is discharged to produce a high current that generates a strong magnetic field of up to 20 Tesla, which is utilized for joining the cable conductor and the lug. The study examines the performance of the capacitor under different operating values such as voltage, capacitance, and discharge time and investigates the effect of these parameters on the termination quality. The paper presents the experimental results of the crimping, which include the contact resistance, weld strength, microstructure, and defects of the welded joints. The results indicate that the capacitor-based electromagnetic pulse crimping produces welds with high strength and minimal defects. Additionally, the paper discusses the future scope of research in this area and the potential applications of such capacitors in other welding techniques. The findings of this research paper provide valuable insights for engineers and researchers working in the field of energy storage, high-voltage applications and welding.

Comparative Study of Different High Voltage Switches Used in Pulsed High Voltage Application

Sai Kiran Panda, Sabyasachi Mitra, J. Mondal, A. Roy — Fri, 01 Mar 2024 00:00:00 +0000

High-voltage switches play a crucial role in pulsed power applications, where the efficient and reliable control of highvoltage pulses is required. This study aims to compare different types of high-voltage switches commonly used in pulsed power systems including electromechanical switches, vacuum switches, gas-filled switches, triggered spark gaps and solidstate switches. The comparison study focuses on key performance parameters such as voltage handling capability, current carrying capacity, turn-on time, and repetition rates are considered to provide a comprehensive study and analysis of the switch’s suitability for different pulsed power applications. Gas-filled switches such as spark gaps, thyratrons and ignitrons have been used in pulsed power systems due to their high voltage handling capability and low switching losses. However, they suffer from a limited lifetime and require maintenance and periodic replacement. Solid-state switches, i.e. Silicon-Controlled Rectifiers (SCRs), Insulated Gate Bipolar Transistors (IGBTs) and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) offer advantages in terms of longevity, reliability, and reduced maintenance. However, they have limitations in high-voltage applications and exhibit higher switching losses. The findings of this comparison study will assist researchers, engineers, and system designers in selecting the most appropriate high-voltage switch for pulsed power applications, considering the specific requirements and constraints of the system. This will ultimately contribute to the advancement and optimization of pulsed power technologies across a wide range of scientific, industrial, and strategic applications.

Challenges in Measurement of Low-Value ESL and ESR of High-Performance PFN Capacitors for Klystron Modulator

Fri, 01 Mar 2024 00:00:00 +0000

In the high voltage line type pulse modulators, Pulse Forming Network (PFN) capacitors are one of the important components. These capacitors operate at peak kilo ampere current range and at repetition rate in the range of a few hundred hertz. The performance of these capacitors is critical w.r.t. overall system performance, and they are required to operate at high power density and low losses with high reliability. The Equivalent Series Inductance (ESL) and Equivalent Series Resistance (ESR) are two critical parameters that affect the performance of these capacitors. PFN modulator demands a capacitor of very low ESL and ESR for reliable operation and generation of high-voltage pulses. Higher ESR value adversely affects the performance of the capacitor by raising its temperature and thus deteriorating its life. ESL value does not directly affect life, but it affects the quality of high voltage pulse. In RRCAT, the PFN capacitors purchased from Indian manufacturers were showing high-temperature rise and failures. Therefore, new capacitors were designed to have lower ESL and ESR values. Measurement of ESL and ESR is important to evaluate the performance of the capacitors. The low value of these parameters makes their measurement a challenging task and requires special techniques. For low values of ESL and ESR (less than 100 mΩ) measurement, a differential measurement technique was used in which modification and different layouts were explored to improve the repetitive accuracy of the measurements. The differential ESR and ESL measurement techniques with more emphasis on the low-value ESR measurement will be discussed in the paper.

EMI EMC: Background, Standards and Design Aspects

Hari Balakrishna, Ankit Agrawal, Shivam Gupta, Vivek Sanadhya — Fri, 01 Mar 2024 00:00:00 +0000

In a multi subsystem environment, in order for the subsystems to interoperate, electromagnetic interference and compatibility aspects have to be addressed. This is a critical aspect of the design and identifying the EMI and EMC aspects at the specifications stage itself lends to a better final design outcome. This paper provides a brief overview of the current standards and elucidates the EMI EMC design aspects with the help of three case studies viz. Antenna Platform for LCA MMR, IDSN32 SRCU and Anuchitra DBS. The methods, measures and design practices used for a successful EMI-EMC performance outcome are elucidated.

Shielding Effectiveness of HV-HF Transformer for Accelerator Applications

Fri, 01 Mar 2024 00:00:00 +0000

High-voltage high-frequency transformers are employed in DC accelerators. The high frequency produced by the inverter at lower voltage is stepped up to several tens of kilovolts using step-up transformers. These transformers are subjected to high-frequency transients from high-voltage multiplier columns. Electrostatic shielding is very effective in common mode noise reduction. However, in accelerator applications, shielding effectiveness obtained using conductive shields is found compromised in practice. This paper investigates the reasons behind this phenomenon and explores remedial measures.

Effect of Electrode Protrusions on Properties of Polyethylene as a Dielectric for Capacitors

Parimal Sharma, C. Iyyappan, C. C. Reddy — Fri, 01 Mar 2024 00:00:00 +0000

The electric field distribution within capacitors and cables is predominantly influenced by the geometrical profile of the electrodes. It is important to consider the presence of protrusions on the electrode surface, as they can significantly impact the electric field intensity. These protrusions can intensify the electric field, potentially leading to premature breakdown of the dielectric material. Hence, the presence of protrusions on the surface of electrodes in high-voltage capacitors holds immense significance and should be carefully considered in the design and manufacturing processes. In this paper, a capacitor model with protrusions is simulated in FEM-based COMSOL Multiphysics software. Electric field distribution is obtained and the effect of protrusion geometry on peak electric field is analyzed.

Investigation of Planar Antenna Performances on Commercially Available Dielectric Materials

S. Subin, Vijay K. Goyal, Vivek Sanadhya — Fri, 01 Mar 2024 00:00:00 +0000

Planar RF antennas with their conformal geometry, good RF performances and ease of construction find a wide range of applications ranging from mobile phones to RADAR and wearable electronic gadgets to medical implant devices. The selection of a suitable dielectric material is by far the most crucial step in the antenna design process to achieve the desired RF characteristics. The directivity, efficiency and bandwidth of an antenna depend on the substrate dielectric constant, loss tangent and material thickness. This paper investigates the RF performances of two planar antennas designed using two commercially available dielectric materials namely RT Duroid and FR4 with a full wave 3D EM simulation tool. The results show the superior RF characteristics of the antenna designed using RT Duroid over FR4. The antenna designed with RT Duroid substrate is fabricated and the measurement results obtained are found to be in good agreement with the simulation results.

Precision, High Stability High Voltage Module Power Supply for Analytical Instrumentation

Sunil Kumar Sahu, P. G. Abichandani, S. Malhotra — Fri, 01 Mar 2024 00:00:00 +0000

Analytical instruments like mass spectrometer^1-4 require a highly stable environment for precise measurements. A minute fluctuation in supply can cause large errors in measurements. For accelerating the ions in a mass spectrometer, a highly stable high-voltage power supply is required. High voltage power supplies up to 30kV/10W with 10ppm short-term stability are extensively used in various analytical instruments like mass spectrometers, PMT and CEM, scanning electron microscope, electron spectroscopy etc. This paper will illustrate the design concept and implementation of an HV module based on a compound regulatory system, where a linear regulator feeds the power to the switching regulator (ZVS mode resonance converter fly-back topology, SMPS) operating around 100 kHz.

Usage of Energy Storage Capacitors in TE Gas Laser Pulsers

Pallavi Raote, J. P. Nilaya, D. J. Biswas — Fri, 01 Mar 2024 00:00:00 +0000

An energy storage capacitor is crucial for both electrically pumped and optically pumped pulsed lasers. In electrically pumped lasers, the energy stored in the capacitors is directly deposited into the lasing medium, while in optically pumped lasers, it energizes the flash lamp that, in turn, pumps the lasing medium. We discuss here the application of energy storage capacitors in the operation of electrically pumped pulsed gas lasers. Increasing the operating pressure of the gain medium, a prerequisite for obtaining higher energy from the laser, has resulted in great advancements in the gas laser pulse technology. This progress has led to the development of transverse electric discharge pumping, enabling easy scalability of gas pressure and achievable output power. An ideal TE pulser efficiently charges the capacitor to an appropriate voltage with minimal energy dissipation on the charging element and facilitates a rapid and uniform transfer of this stored energy into the lasing medium before a glow-to-arc transition can set in. Various types of pulser circuits employed to energize pulsed gas lasers are described in this paper.

Review of High Voltage Pulsed Power Supplies and Power Electronics in Pulse Power Generation

Khuban Lateef Khan, Rishi Verma, Amitava Roy — Fri, 01 Mar 2024 00:00:00 +0000

Recently, pulse-shaped power supplies have become more popular. Pulsed power is versatile and useful as a supply method since it can take several shapes and has many pulse characteristics. The release of electrons, protons, and neutrons from an atom and the synthesis of molecules to generate ions or other molecules require a lot of immediate energy. Pulsed power is needed for decomposition, molecular fusion and material joining, radiation generation (e.g., electrons, lasers, radar), explosive processes for concrete recycling, wastewater and exhaust gas treatment, and material surface treatments. Industrial and environmental applications require pulsed power, which requires efficient and adaptive pulse modulators. Higher-quality repeating pulses are needed for plasma fusion and laser weapons. Marx Generators, Magnetic Pulse Compressors, Pulse Forming Networks, and Multistage Blumlein Lines have several uses. Pulse modulators use spark gap and hydrogen thyratron gas/magnetic switching technologies for their high voltage tolerance and low-rise times. These creatures are inefficient, unreliable, repetitious, and short-lived. These devices are heavy, bulky, and expensive. Solid-state switching technology can replace conventional devices, improving pulse supply. High-frequency switching repeats the pulsed power supply. These items are compact, efficient, affordable, reliable, and durable. Solid-state transistor applications may not meet switch voltage ratings and rise time constraints. Various power electronics configurations can produce solid-state high-voltage pulses.

A Comparative Study on Lattice Tower Angle Member Capacities as Per Indian, American, and BSEN Standards

Sankara Ganesh Dhoopam — Fri, 01 Mar 2024 00:00:00 +0000

The transmission lines and Telecommunication networks are normally supported by lattice towers. Therefore, the reliability of these essentials depends much on the reliability of the towers and their foundations. In Both telecom and power transmission line sectors, the towers are mass-produced and generally based on optimized tower weight and foundation volumes. The weight of a tower is influenced to a great extent by the selection of tower configuration, choice of bracing patterns, choice of steel grade, and profile type. The towers in general are lattice types consisting of main legs, diagonals, horizontals, cross-arm members, and peak members. The telecommunication and power transmission line tower members are generally made of steel equal-angle sections. These tower members are modeled and analyzed as pin-jointed 3-dimensional space truss models and the members are subjected to axial forces, either axial compression or axial tension in nature. Estimation of member compression capacity is the most vital parameter in design as per respective local standards and proving those estimations during full-scale model tower testing if carried out. This paper presents the differences in axial compression capacity of angle members as per Indian, American, and European standards viz., IS: 802 (Part 1/Sec 2)-2016, IS 800-2007, ASCE 10-15 and BS EN 1993-3-1:2006.

Design and Development of Electromagnet Power Supply for Burst Mode Repetitive High Power Microwave Sources

Fri, 01 Mar 2024 00:00:00 +0000

Single frequency High-power microwave sources like Backward Wave Oscillator, Relativistic Magnetron etc., require a high magnetic field of about 1T to 4T for efficient operation. Single-shot HPM systems usually consist of pulsed magnetic systems. However, for repetitive HPM generation, a continuous magnetic field is required. To obtain a continuous high magnetic field in the required volume usually three solutions are worldwide preferred i.e., permanent magnet, DC electromagnet with cooling arrangements and superconductor-based magnetic coil. All these three systems are bulky, expensive and technologically demanding. In this paper, a novel power supply has been suggested that discharges a charged capacitor through a magnetic coil keeping the discharging current constant for a small period like hundreds of milliseconds to a second. An IGBT switch is used to discharge the capacitor1. The duty cycle of the IGBT switch is controlled using a current feedback signal from the hall sensor, thus keeping the current steady at a preset reference value. An experimental setup has been developed using a 300mF capacitor. A constant current up to 500A is achieved for 200mS. This system is scalable. For a longer duration of operation, more capacitor modules need to be added. Details of design, development and experimental results are presented in this paper.

Use of Data Analytics for Power Plant Operation Optimization

Arnada Prasad Samal — Fri, 01 Mar 2024 00:00:00 +0000

Optimized operation and maintenance of a power plant to improve the KPIs is the key to success. Forced outages not only make the unit unavailable but also increase the number of start-ups and hence high cost and deteriorated plant life. Fault diagnostics and prediction of future behavior of equipment by data analytic techniques will be very handy in improving reliability. On the other hand, the cost of generation depends upon how efficiently the plants are operated. Any deviation from the optimized design point, results in losses and hence as far as possible the deviations should be minimized. However, the deviations are unavoidable due to various reasons. Along with efficient operation, Environmental compliance, and flexibility is also to be ensured to meet the statutory requirements. With the advancement of computing techniques, data analytics, and Artificial Intelligence are being used for the optimization of many industrial processes. Given the background, the objective of this paper is to study and suggest how Data Analytics can be utilized for the optimization of power plant operations to improve reliability, efficiency, and flexibility, and minimize the impact on the environment. Many statistical methods are available to identify the hidden pattern in the data which can be used for optimisation of processes. AI is used for process control, diagnosing faults, and predicting of future behaviors so that advanced action can be taken to avoid surprises. The domain expertise along with data analytic methods can be utilized to find solutions to a variety of problems. In this paper, a comprehensive data analytic tool with four modules i.e., “Efficiency optimization”, “Plant Health monitoring and reporting”, “Optimization of life consumption” and “Environment protection” has been conceived for application. These Modules work in an integrated manner and shall monitor, optimize, control, and report/advise. The tool shall have a digital replica of the individual equipment for simulation individually as well as in combination with other related equipment for whole plant performance prediction and diagnosis. The replica shall use its database for machine learning and for running of diagnostic process.

Meeting Power Challenges with TCSC and Next Generation TCSC: SPLIT TCSC

Niharika Agrawal, Faheem Ahmed Khan, Mamatha Mahesh Gowda — Fri, 01 Mar 2024 00:00:00 +0000

The electricity demand is continuously increasing due to population growth and development. There is a lack of generation and transmission facilities, so the existing system is used to transfer more power to meet the rising power demand. This causes overexploitation of the present power system and gives rise to stability problems. The power transfer capacity of the existing transmission lines can be increased by using fixed capacitors by varying the impedance of the transmission lines, but they have associated SSR problems. In this situation FACTS devices TCSC are used to control power flow in the system. TCSC mitigate power oscillation, stability problems and various power quality problems like voltage sag and voltage swell created due to disturbances or faults. In the proposed work the TCSC is used to increase the power flow capacity of the system without the need for investment in new lines and systems. The active power transfer with different controllers is discussed. The two modules of TCSC with different ratings are taken and analysed. Then there are some problems in ordinary TCSC too. On tuning the ordinary TCSC in the critical region of the reactance characteristic curve there is observed a large gap of reactance at both the inductive and capacitive critical regions. Because of the large elapse/gap of reactance in this region small change of power demand is not possible in the power system which reduces the flexibility of the power system, and it becomes rigid. These challenges of ordinary TCSC are met here by the next generation device of TCSC: Split TCSC in the power system. Split TCSC tunes the critical region reactance with many firing points and hence elapse of reactance is very small which allows for fine tuning of power flow over the transmission line thus mitigating the problems of ordinary TCSC. Split TCSC includes all the other benefits of ordinary TCSC such as increased power flow, stability improvement, damping oscillations, and mitigating SSR as it belongs to the family of TCSC. Thus, in the proposed work the power challenges are met using TCSC and Split TCSC.

Mathematical Simulation for Right of Way Corridor for Overhead Transmission Line

Rajiv Ranjan, P. Sowmya Krishnan, Animesh Kumar — Fri, 01 Mar 2024 00:00:00 +0000

Transmission lines play a vital role in the operation of a reliable electrical power system and that is why the transmission line system is considered as a lifeline system for power supply. The transmission line traverses across the length and breadth of the country, and it crosses all the natural reserves like forests, rivers, vegetation, mountains, etc., to make the system effective, Right of Way (ROW) plays a decisive role in the transmission line. But in today’s growing population and economy, land acquisition for the construction of transmission lines is a major bottleneck. This leads to huge compensations for the utilities and a threat to the natural resources. This paper attempts to arrive at a mathematical simulation for effective ROW by studying different codal provisions and utility practices. The approach is made to make efficient use of the land available without compromising any relevant parameters for ROW.

Review of Cockcroft-Walton High Voltage Low Current DC Power Supplies

Urmil Thaker, Santosh C. Vora — Fri, 01 Mar 2024 00:00:00 +0000

High-voltage power supplies are key for developing particle accelerators, neutron generators, x-ray systems, ion implantation, etc. This paper reviews various developed voltage low current power supplies based on Cockcroft-Walton voltage multiplier circuits for accelerator-based neutron sources and other industrial and medical applications. The paper presents a detailed review of the topology of the power supply used for the high voltage generation, the key design parameters, key active and passive components used in the High Voltage (HV) system, key experimental results, protection and measurement circuit used in the power supply and about the system performance. The improvement that occurred in the size and performance of the power supplies due to the development in the technology of the magnetic components, semiconductors and energy storage devices in successive years is apparent in the discussion. Finally challenges and possible solutions for the compact design and system performance are concluded for the development of high voltage low current power supplies.

Experimental Investigation of Lateral Load Test on Diagonal Braced 3M Glass Fiber Reinforced Polymer Transmission Tower

R. Krishnasamy, S. Christian Johnson, P. Saravana Kumar, R. Mohanraj — Fri, 01 Mar 2024 00:00:00 +0000

Over the past decades, numerous research and development studies worldwide have focused on various civil engineering applications involving composite materials. Presently, recent investigations have explored the utilization of Glass Fiber Reinforced Polymer (GFRP) members in tower panels, composite cross arms in towers, full-scale 66 kV FRP double circuit towers, FRP towers created through filament winding techniques, GFRP triangular base communication towers, GFRP square base tower panels with bolted connections and strength and stability assessments of Glass Fiber Polyamide (GFP) towers and carbon fibre reinforced towers. The susceptibility of conventional TLT members to theft, where thieves often cut and steal them, prompted the suggestion to consider TLTs constructed with different materials. The study for examining the behavior of hybrid joints in angle-to-angle connections, with an ‘e/d’ ratio is 5. The well-performing hybrid joint has been implemented in a GFRP tower model and subjected to lateral loading to assess the effectiveness of such joints.