High Voltage Power Transmission Research Articles

Comparison of short-circuit ratios of converter control for high-voltage DC power transmission systems

Comparison of short-circuit ratios of converter control for high-voltage DC power transmission systems

Location of overhead power lines within Bukowe hills mesoregion in relation to the assessment of forest area fragmentation

National power grid in Poland requires modernisation, therefore by 2030 numerous actions are scheduled regarding the expansion of the existing network and the construction of new electricity transmission lines (power lines). The planned activities will undoubtedly change the quality of landscape and result in fragmentation of forest habitats, some of which are characterised by high biodiversity and constitute a key element of ecological corridors. The aim of the present paper was to outline the issue of the impact of the power line corridors on forest habitat fragmentation, as well as to present the GuidosToolbox software (Graphical User Interface for the Description of image Objects and their Shapes) used, among other things, for the determination of the degree of fragmentation of forest habitats. The analysis concerned the Puszcza Bukowa forest, which is a part of the Natura 2000 network and is protected under the Szczecin Landscape Park ‘Puszcza Bukowa’. Despite abundant natural assets of the Puszcza Bukowa forest, it was necessary to run many power lines through its area due to location of the forest in the vicinity of the Szczecin agglomeration. The course of power lines contributed to the fragmentation of the discussed forest complex and to the depletion of its interior classified with the GuidosToolbox software as ‘Intact’. The software discussed in the present paper may prove useful in the identification of the degree of forest area fragmentation, connected with the course of high-voltage power transmission lines, and in the assessment of the impact of the planned investment projects on biocenoses.

Alumina Trihydrate Effect on Flashover Voltage of Polyester Insulators by Whale Optimization Algorithm Technique

Ceramic materials are commonly used as outdoor insulators for high-voltage power transmission lines. Presently, these ceramic insulators are replaced by composite polymeric insulators with polyester, especially in rainy areas. Unlike ceramic materials, polymer materials have a shorter life, so fillers are used to improve their physical and chemical properties. This paper aims to improve the flashover voltage performance of polyester loaded with Alumina Trihydrate filler in wet weather condition. Due to the high cost of raw materials (polyester and Alumina Trihydrate filler), the Whale Optimization Algorithm model was used to predict the best concentration of Alumina Trihydrate filler to give the best value of flashover voltage. The model is based on experimental data of flashover voltage measurements. A positive correlation of the calculations from the Whale Optimization Algorithm model with experimental data has been demonstrated. The results showed that the flashover voltage performance of polyester is increased with the increase of Alumina Trihydrate filler concentration. Also, the optimum concentration of Alumina Trihydrate filler and flashover values predicted by the MATLAB Whale Optimization Algorithm are very accurate.

Modeling the Reliability of High-Voltage Power Transmission Lines Taking into Account the Influence of the Parameters of a Sharply Continental Climate

Modeling the Reliability of High-Voltage Power Transmission Lines Taking into Account the Influence of the Parameters of a Sharply Continental Climate

ОЦІНЮВАННЯ ВПЛИВУ НЕСИМЕТРІЇ ЛІНІЇ ЕЛЕКТРОПЕРЕДАВАННЯ НАДВИСОКОЇ НАПРУГИ НА ВИЗНАЧЕННЯ ПАРАМЕТРІВ КОМПЕНСАЦІЙНОГО РЕАКТОРА

The article shows the urgency of the problem of studying resonant processes in extra high voltage power lines. The research of processes in extra high voltage power transmission lines is carried out to develop and implement measures to prevent overvoltages. Resonant overvoltages arising because of open phase modes of operation of the extra high voltage transmission line are considered. The paper shows the influence of the levels of longitudinal asymmetry on the calculation of the resistances of compensating reactors to reduce the values of overvoltages in the pause of single-phase automatic reclose. The degree of influence of the wire transposition scheme on the choice of the resistance of the compensation reactor and on the values of resonant overvoltages in the cycle of single-phase automatic reclose is considered. Estimation of asymmetry coefficients for different transposition schemes is performed. To select the resistance of the compensation reactor, the data of the existing high-voltage transmission lines of 750 kV were taken. Recommendations for the implementation of measures to prevent and limit resonant overvoltages are given. The current theoretical and practical problems of operation of the extra high voltage power line are considered and the ways of further research are shown. References 14, figures 5, tables 2.

Photothermal Radiometry Depth-Profiling of Aged Silicone Rubber Composite Insulators

Thermal and structural properties of aged silicone rubber composite insulators widely used in high-voltage transmission power systems were characterized by photothermal radiometry (PTR) to evaluate the degree of aging. A two-layer PTR theoretical model was developed to extract the thermal diffusivity and the aged layer thickness from the PTR frequency-scan data. Results show that aging generated an aged layer with a reduced thermal diffusivity at the surface of the composite insulator. Further investigation into the depth dependence of the thermal diffusivity of aged composite insulators found a monotonically increasing thermal diffusivity along the depth direction, approximating to a hyperbolic tangential profile, which indicates a spatially continuous variation from surface to bulk during the aging process. The PTR depth-profiling of thermal and structural properties provides a deeper understanding of the aging process in composite insulators.

Analyzing the Limit Loading of Transmission Tower by Means of Finite Element Model

The truss structure has been widely used in the area of high-voltage electric power transmission due to its limited mass and great stiffness. The carrying capacity should be known in advance before the practical usage of transmission tower. As a result, analyzing the limit loading of transmission tower can be significantly useful. In this research, a model of transmission tower structure has been established by a software named Abaqus 6.14. By imposing different loading forces to the finite element model, the locations of limit stress and displacement were figured out. It has shown that the truss structure in this article can bear no more than 198 kN of loading. Stresses meanly distribute in the two side of the tower body, decreasing with the increasing height. The limit stress shows up at the bottom and is at same side of loading force. Stress and displacement responses fit Hooke’s law perfectly, in other words, the proposed finite element model can be used in the design of transmission tower in practice.

ELECTROMAGNETIC INTERFERENCE (EMI) PRODUCED BY HIGH VOLTAGE TRANSMISSION LINES

Electromagnetic interference in high voltage transmission lines has been an interest topic due to its effect on human health, plants, electrical and telecommunication equipment. Extremely high voltages (EHV) in transmission lines are reasons of electrostatic effects, while short circuit currents and line loading currents are responsible for electromagnetic effects. The aim of this research is to analyze electromagnetic fields in high voltage transmission lines in theoretical study and calculating its level in overhead T. L and therefore estimated the EMI produced, by employing a mathematical model of 230 KV tower double circuit configurations of high voltage transmission lines. The calculation is based on computer aided analysis (CAA) by using fields and corona effects software (FACE). It's found that the overhead power lines of general frequency (50 Hz) generates a highly intense magnetic field, the electromagnetic fields depends on the distance from sources and the type of line configuration. They decrease as the distance increase from the tower and conductors and increase with a high current. The strength of an electric field is proportional to the voltage of the line and the magnetic field strength is proportional to the current in the high voltage transmission lines. Distribution line with a high current load may produce a magnetic field that is as high as those produced by some high voltage transmission lines. Some techniques of reduction of the effects of electromagnetic interference have suggested such as rearrangement conductors of transmission line, and distance from phase conductor and grounding system. The study recommended to keep safety distance operation in high voltage transmission lines with the necessity for engineer to take into account the effect of electromagnetic interference in the design stage of high voltage transmission power system, and to avoid any addition cost may be occur due to neglected effects of electromagnetic interference that produces by high voltage transmission lines

Cumulative Fatigue Damage Balancing for Modular Multilevel Converter

With many advantages, modular multilevel convert (MMC) has been extensively used in high and medium voltage power transmission projects. The thermal performance and reliability of components in MMC are key issues in system operation. However, in the current research on the reliability of MMC components, there are few methods to improve service lifetime expectancy of the components. This paper proposes a balance control algorithm, based on the cumulative fatigue damage of components, feedback to the control terminal for allocating the sub-module (SM) operating state and generating trigger pulses. Finally, the effectiveness of the proposed algorithm is verified and discussed in case studies. It is found that this algorithm is able to improve the aging degree of components in the meanwhile, the improvement in MMC reliability comes at the cost of slightly increasing capacitor voltage fluctuations and total harmonic distortion (THD). Due to the limitation of capacitor thermal performance, SM capacitor banks become a weak link in MMC reliability.

Site selection by using the multi-criteria technique-a case study of Bafra, Turkey.

Population growth, which is the main source of the biggest problems of the world today, combined with migration from rural areas to urban centers, causes the urban centers to be even more concentrated. This necessitates the opening of new residential areas in many city centers, but new residential areas are mostly determined by the decisions of local authorities, who may not base their decisions on scientific data. With the wrong area selection, ordinary natural events can be potentially catastrophic. Such events can result in large numbers of casualties and material damage every year. In this study, an example of applying a method for location selection using various parameters has been realized. The study focuses on Bafra, Turkey (the study area). Risk maps were created in terms of floods and overflows; maps of regions and high-voltage power transmission lines that enjoy a protected area status; and maps of regions in terms of biocomfort suitability. As a result of the evaluation made according to these criteria, it is calculated that only 1.96% of the total working area is suitable for use as a residential area. In relevant literature studies, it was observed that the studies related to the selection of residential areas were carried out only depending on a single standard or criterion. Some suggested biocomfort, and others used vulnerability to risks such as landslide, flood, and earthquakes as their main principle. Studies based on multi-criteria were generally used for purposes such as solid waste site selection and determination of the road routes. The study aims to shed light on the multi-criteria method in an attempt to standardize it in regional planning studies and to inspire similar studies in which different criteria can be used to achieve the maximum efficiency.

Electrical tree degradation in high‐voltage cable insulation: progress and challenges

High-voltage direct current (HVDC) and high-voltage alternating current (HVAC) cables are the most important equipment for high-voltage, large-capacity and long-distance power transmission. Electrical tree is a pre-breakdown phenomenon leading to failure of insulation materials, and it is the major issue that threatens the safe and stable operation of HVDC and HVAC cable systems. This study summarises and analyses the achievements in the research of electrical tree for HVDC and HVAC cables. The initiation mechanisms of the electrical tree, including Maxwell electro-mechanical stress, charge injection–extraction, charge trapping and electroluminescence theories, are elaborated for fully understanding the electrical degradation process in insulation materials. Then, the influences of the high electric field, high temperature and mechanical stress on electrical tree behaviours are discussed, and the relationship between charge transport and the electrical tree is analysed and illustrated. The suppression methods of the electrical tree are put forward by introducing inorganic and organic additives into insulation materials, and the suppression mechanisms are presented from the viewpoints of the structure-property and microscale–macroscale relationships. Recently, the electrical tree research studies are focused on the high-precision of initiation models, high-dependence of multi-physical fields and high-efficiency of suppression methods. The achievements provide theoretical support for improving the electrical performance of insulation materials, while it is a practical problem to explore their application feasibility in HVDC and HVAC cable.

A Procedure for Placing Shunt Reactors in High-Voltage Networks and Justification of its Efficiency

In recent years, the controlled shunt reactor (CSR), a type of FACTS device, has been widely used to regulate voltage and reactive power flows in the high-voltage electrical network. The selection of location and the determination of the law of CSR control under the stochastically variable operation of high-voltage power transmission lines are associated with numerous technical and economic factors. At the same time, one should take into account such limiting conditions as ease of use, performance, purpose, and location in the system, as well as the time of commissioning. In the proposed procedure, these factors are considered as fuzzy constraints. The paper proposes a procedure for CSR placement in the 330 kV electrical network of the “Azerenergy” system for control of reactive power flows, given the mentioned fuzzy constraints. The obtained simulation results demonstrate the advantage of the proposed procedure. The computational experiments confirm the CSR efficiency.

Optimized Portable Unilateral Magnetic Resonance Sensor for Assessing the Aging Status of Silicon Rubber Insulators

Silicone rubber insulators (SRIs) play an important role in high-voltage power transmission lines. Given that SRIs critically threaten the safe operation of the power grid, quantitatively assessing the aging status of SRIs in situ is crucial. In this article, a portable unilateral magnetic resonance (UMR) sensor with a U-shaped magnet structure and its measuring circuit were designed for the nondestructive detection of the aging status of SRIs in situ. First, the optimization efficiency of the magnet structure was improved through a uniform design method. Then, the planar radio frequency (RF) coil was designed by the finite-element method. Furthermore, the demagnetization effect of eddy currents induced in metal materials on the RF magnetic field was analyzed. We measured the SRI sheds at different service times and obtained the corresponding 1H transverse relaxation decay curves by importing the Carr- Purcell-Meiboom-Gill (CPMG) sequence. Finally, the transverse relaxation decay curves were postprocessed using inverse Laplace transformation, and the 1-D spectrum distributions of transverse relaxation time (T2) were obtained. The results reveal that T2 of the surface of the SRI shed decreases as the service time of the SRI increases. In addition, the difference in T2 between the surface and interior of the SRI shed increases. The comparison experiments demonstrate that the U-shaped sensor designed in this article is superior to the curved sensor previously designed by our team. The effect of temperature variation on SRIs aging assessment was considered at last.

정적 하중 조건의 고전압 전선용 플라스틱 얼레의 구조 강건성

나무로 만들어진 현재의 고전압 전선용 얼레는 제조 과정에서 비용이 많이 들고 무겁다는 단점과 함께 재사용 측면에서도 어려움이 있기 때문에 대안으로 공학용 플라스틱 소재를 사용하는 것이 고려되고 있다. 본 연구에서 해당 플라스틱 소재에 적합한 컨셉 모델을 제안하여 최대 자중과 등가 충격 하중에 대해 정적인 구조 강도를 가지는지를 검증하였다. 최대 적재 중량인 4,000kg 조건에서 발생되는 자중에 의해 제안된 모델의 최대 응력을 분석하였으며, 자유 낙하 상태에서 발생되는 등가 충격 하중을 활용한 구조의 정적 강도 해석도 수행하였다. 두 가지 해석 결과를 바탕으로 기존의 나무로 만들어진 전선용 얼레를 새로 제안한 플라스틱 소재의 컨셉 모델로 대체할 경우 정적 구조 해석 측면에서 충분한 타당성이 있음을 확인하였다.

Wireless Power Transfer Using Domino-Resonator for 110-kV Power Grid Online Monitoring Equipment

Nowadays, smart grid online monitoring systems are widely used in high-voltage (HV) power transmission networks, leading to the requirement of reliable power supply units for the monitoring equipment. In this article, we present a novel solution to harvest energy from the magnetic field around a 110-kV transmission line and transmit the energy to the online monitoring equipment on the transmission tower over 1.1 m insulation distance. Printed circuit board resonators are covered by the composite insulation material forming the first HV insulator with wireless power transfer (WPT) capability. The prototype of the HV insulator has passed the rigorous HV tests at 550 kV. The WPT characteristic of the HV insulator including the effects of corona rings is analyzed and verified by practical measurement.

Computer simulation of the operation of the device for monitoring the state of high-voltage insulators during its operation

This article presents the design and operation principle of the high-voltage isolator state indicator of the high-voltage power transmission line. The present indicator operates without the use of a separate power supply on the principle of electric field energy accumulation. The efficiency of such a device requires that as little as possible be lost during energy storage. Therefore, the development of criteria for selection of elements of the indicator circuit with minimum leakage currents is fundamental, which was one of the first tasks set during simulation. Calculations were carried out by constructing and analyzing a three-dimensional model of the insulator and solving differential equations by finite element method in the COMSOL Multiphysics software environment. The object of the study was a linear suspended insulator with polymer insulation of LK 70/35 type, designed for insulation and attachment of wires of AC overhead power transmission lines with voltage from 35 to 500 kV. Computer simulations and all calculations were made for the said insulator. On the basis of the obtained results of simulation of the insulator operation with the optical indicator installed on it, requirements to electronic components of the developed scheme were formed and corresponding components were selected.

Role of Micro and Nano Filler Combination in Hydrophobic Recovery of Glass Fiber Reinforced Epoxy Composites under Various Contaminants

Use as outdoor insulators in high voltage power transmission is a potential application of epoxy composites. Vulnerability of these insulators to various stresses when exposed to external environment, limit their potential. Better pollution performance in hostile environments can be achieved in these composites by using nano and micro combination of fillers. This paper discusses the merits of using combination of micro and nano fillers consisting of silica, alumina, ATH, CaCO3 and MgO in glass epoxy to demonstrate that they serve a better alternative to the conventional glass epoxy composite insulation systems. Extensive investigations have been carried out on hydrophobic recovery of these composites for understanding their pollution performance under various contaminants such as NaCl, seawater, acid and cement. The addition of filler combinations to glass epoxy enhanced the hydrophobic properties of the composites compared to the glass epoxy without fillers. The results revealed that the composite with MgO filler showed 37% increase in contact angle in as-cast form compared to contact angle of epoxy without fillers.

THE ANALYSIS OF LANDS IN SECURITY ZONES OF HIGH-VOLTAGE POWER LINES (POWER LINE) ON THE EXAMPLE OF THE FERGANA REGION

Practice shows that the lack or late receipt of information with special conditions for the use of territories often has a negative impact not only on the budget and time frame for the construction of a real estate facility, but also on the fate of the built facility in general. The protection areas of underground and above-ground engineering communications play an important role for the future in land use. And also, when using these lands for agricultural needs, with the correct organization of cadastral relations represents the relevance of the issue under study. In the present, as an example, a section of high-voltage power transmission lines (power lines) of 1 km length is presented. KEY WORDS: security zones, land plot, information about zones, high-voltage zones, power transmission lines, pipelines, gas pipelines, bonality score, engineering networks, construction of buildings and structures.

Right-of-Way Monitoring Camera Storage Energy Around High Voltage Power Transmission Using Hybrid Energy Harvesting-Mfield, Efield to Super Capacitor Batteries Back-Up Charger

Magnetic and electric fields are the loss of the field that occur continually around high voltage transmission lines in the power systems. The current and voltage are significant variables for generating magnetic and electric fields respectively. This research is interested in the development of these fields to store harvested energy and the correct way of using camera node monitoring. In this work, the authors purpose energy harvesting from magnetic and electric fields, with a case study based on 230 kV and 500 kV in the Thai power transmission system. Two approaches are used for the hybrid harvester, with the first method using the number of coil turns in each dielectric physical model, such as air, metal, or ferrite dielectric to harvest the magnetic field from the power line. The number of coils uses N-turn, 250 N, 600 N, and 1000 N, with a dielectric distance of 4, 6, and 10 cm is used. The second approach is electric field harvest, using a varied electrode plate from ground to an electric conductor, with three plates used in the experimental model. At the investigational stage, the common plate is varied from the nearest conductor to the ground to analyses data results. After that, two sources of energy are taken to the hybrid storage harvester using the rectifier circuit and stored in a super capacitor. The energy from the backup super capacitor is used to supply to the right-of-way camera monitoring or other low energy source devices. This study result show that energy harvesting from the field harvest varied according to the number of coil turns, distance of the dielectric, size of the plate, and distance from the high voltage conductor. The voltage from field can be stored to super capacitor from 0 V to approximately 0.8 V in 180 min for a magnetic field yield. Furthermore, the electric field harvesting can charge the supper capacitor from 0 to 15 V in 180 min. The research therefore combines two approaches for charging in the battery backup using low energy devices, referred to as a hybrid harvesting approach. This research is advantageous for right-of-way camera monitoring supply on high voltage–power transmission lines.

Assessing the type and quality of high voltage composite outdoor insulators by remote laser-induced breakdown spectroscopy analysis: A feasibility study

The use of composite polymeric insulators in overhead high voltage (HV) power transmission lines and in substations has been rapidly growing, as a result of their excellent operational performance, even under environmental pollution conditions. However, it has been observed that the insulation capacity of the composites deteriorates gradually for in-service insulators as a result of ageing, caused by several processes arising because of environmental, electrical and mechanical stresses. For these reasons, development of non-destructive diagnostic techniques for real-time, on-site inspection of the insulators' condition is required for ensuring high reliability of power transmission networks. To this end, laser-induced breakdown spectroscopy (LIBS) is found to offer an effective and reliable method for assessing the state of polymeric insulators, primarily silicone rubber (SIR) ones, that have been in service for up to 20 years on the HV power network of Crete, Greece. Determining the type of composite and furthermore the chemical integrity of the insulator is based on simple spectral indicators, which reflect the extent of chemical modifications induced on the insulator surface, as found in both standard and remote LIBS measurements performed in the laboratory. As a result, a stepwise diagnostic procedure was proposed and tested in an outdoors campaign, demonstrating that LIBS can become a field deployable technique for the efficient and reliable assessment of the performance of HV outdoor insulators in service.