Возбуждение глобальных искусственных сигналов диапазона Рс1 в эксперименте FENICS-2024: 1. Наблюдения

Electrical power systems are different in their sizes because of their amount of generation power stations, substations, transmission lines and loads. Therefore, these factors may impact on short circuit levels values. Capacity of power stations and dummy transmission lines in Extra high voltage grid (400kV) of the Iraqi Electrical power grids cause high short circuit levels values such that exceed both rating of the peak and breaking capacity of switchgear equipment's. Reduction of short-circuit levels by using Fast-acting Flexible Alternating Current Transmission Systems (FACTS) types devices in power grids maintain the operation of power grids with acceptable value of short circuit levels for their electrical equipment's and preventing cascading event outages which may lead to blackouts. This paper mainly studies strategies on how to add Short Circuit Current Limiter (SCCL) device by determining its number, value and location of connection in power grids by programing with (PSS™E version 30.3 Package Program). IEEE 25-bus system is used for testing the adding series SCCL at power transmission lines method procedure. The results of adding series SCCL with power transmission lines give significant reducing short circuit levels for the stations have highest short circuit levels in order to prevent the blackouts of overall power grid.

Impact of high-voltage power transmission lines on photovoltaic power production

Geomagnetically induced currents (GICs) represent a significant challenge for society on a stable electricity supply. Space weather activates global electromagnetic and plasma processes in the near-Earth environment, however, the highest risk of GICs is related not directly to those processes with enormous energy yield, but too much weaker, but fast, processes. Here we consider several typical examples of such fast processes and their impact on power transmission lines in the Kola Peninsula and in Karelia: interplanetary shocks; traveling convection vortices; impulses embedded in substorms; and irregular Pi3 pulsations. Geomagnetic field variability is examined using data from the IMAGE (International Monitor for Auroral Geomagnetic Effects) magnetometer array. We have confirmed that during the considered impulsive events the ionospheric currents fluctuate in both the East-West and North-South directions, and they do induce GIC in latitudinally extended electric power line. It is important to reveal the fine structure of fast geomagnetic variations during storms and substorms not only for a practical point of view but also for a fundamental scientific view.

Along with the rapid economic development in recent years, people's demands for electricity have also been increasing very rapidly, which makes the power industry grow very fast, however, there have also been new challenges for the safety of the grid. Due to the complexity of China's topography, many power transmission lines under construction and planning are inevitable to pass through the high-altitude areas. Due to the high altitude and low air pressure, a number of external environmental factors are quite different from these of the low-altitude areas, and all these factors have a great impact on the power transmission lines, which will bring a lot of special problems to the design and operation of the power transmission lines. This paper describes the finite element method analysis which is used to calculate the relevant parameters of power transmission lines in high-altitude areas, as well as the status quo of the research on high-voltage AC power transmission lines in high-altitude areas. By analyzing the status quo of these studies and combined with the actual terrain situations of high-altitude areas, we can provide the construction of high-voltage AC power transmission line in high-altitude areas with some valuable references, thus to ensure the safe operation of such power transmission lines.

Trip faults are obviously increased by frequent lightning strikes, and increasing lightning trip-out seriously affects a system’s stability and power supply reliability. In this paper, the reasons for high lightning trip-out rates in electric power transmission lines are analyzed in detail from three perspectives, as follows: the substandard lightning resistance level, lightning complexity at a mid-point between towers, and the complexity of first and subsequent lightning stroke conditions. Experiments and simulations demonstrate that the solid-phase gas arc-extinguishing method has a strong ability to extinguish power–frequency continuous-current arcs and to protect against first and subsequent lightning strokes. Since the time taken by gas arc-extinguishing is much less than the response time of relay protection, trip accidents caused by lightning strikes can be avoided and the trip rates of lightning strikes can be reduced using this method. The case analysis and practical operation results show that the solid-phase gas arc-extinguishing lightning protection method can reduce the lightning trip-out rate by more than 90%, completely solve the problem of high lightning trip-out rates, and significantly improve the reliability of power supply.

The electrical power generation industry is undergoing significant digital transformation in every aspect. One of the most important assets of this industry is the power transmission line (PTL) system. PTL system distributes electric power for residential and industrial uses. PTL requires regular inspections for early damage detection and maintenance to transmit high-voltage electric power efficiently and reliably. The detection and localization of damage across transmission equipment are crucial, as they help power transmission companies reduce maintenance expenses and prevent unexpected power outages. Traditionally, these inspections have been conducted by line crawling or with the assistance of a helicopter to plan for necessary repair or replacement works before any significant damage that could cause a power outage. These traditional solutions are slow, costly, and dangerous. The emergence of drones, high-resolution cameras, edge computing, and deep learning technology opens the opportunity for PTL inspection using drones. In this paper, the literature review is conducted as a preliminary study for our research. Moreover, the state-of-the-art of PTL technology, the general autonomous drone-based PTL inspection system, is being discussed. Finally, we summarize the research challenge and future direction of research in this field.

Animations of electromagnetic transients in power transmission lines by means of the two-dimensional numerical Laplace transform

In this paper, we investigate the energy problem of monitoring sensors on high-voltage power transmission lines and propose a wireless charging scheme for a Radio Frequency IDentification (RFID) sensor tag to solve a commercial efficiency problem: the maintenance-caused power outage. Considering the environmental influences on power transmission lines, a self-powered wireless energy relay is designed to meet the energy requirement of the passive RFID sensor tag. The relay can obtain the electric field energy from the transmission lines and wirelessly power the RFID sensor tags around for longer operating distance. A prototype of the energy relay is built and tested on a 110 kv line. The measurement results show that the energy relay can provide stable energy even with the influences of wind, noise and power outage. To our knowledge, it is the first work to power the RFID sensor tags on power transmission lines.

The efficiency of power systems is based mainly on the continuity of the service, avoiding faults that suppose economic losses for utilities and users. It is very important to detect, locate and eliminate the faults of power systems, especially on power transmission lines. This paper presents a new method based on non–linear frequency analysis for online detection and location of the high impedance faults on power transmission lines, which has been one of the most difficult problems in power transmission and distribution systems. The proposed technique is based on the non–linear characteristics of the high impedance faults and severely contaminated insulators on power lines. The non–linear frequency responses related to the signal of power line carrier were used to detect the occurrence of the high impedance fault. The location of the fault and the degraded insulator on the power lines could be determined by detecting the position of the non–linear component in the power transmission system. The effectiveness of the method has been verified through simulation studies. The results demonstrated that the proposed method has the potential to be applied in practice to resolve high impedance fault real time monitoring problem.

A special feature of the existing relay protections of power transmission lines (PTL) is their operation on an already existing damage in the electrical network, when the short-circuit current already acts on the primary equipment and on the parameters of the entire electrical network, and when approaching an unacceptable distance to the line of people passes through the human body. To date, there are no relay protection devices capable of shutting down PTL before an emergency or abnormal line operation occurs: when people, mechanisms, or trees approach it at an unacceptable distance. The practical issue of creating a fundamentally new relay protection trigger (RPT) based on measuring high-frequency current in phase wires of PTL is considered. Mathematical modeling of three-phase operation and experimental study of single-phase relay protection triggers in case of emergency and abnormal operating modes on a 50 m long transmission line section were performed. Mathematical modeling was performed in the MMANA GAL Basic V.3.0.0.30 program for the following operating modes: normal, emergency (with single-phase, two-phase and three-phase short circuits), abnormal (interruption of any phase, approaching an unacceptable distance to PTL wires of current-carrying devices). As a result of experimental studies, quantitative indicators of changes in the parameters of the high-frequency current generated in the phase wire during short circuits, approaching the wire of a conducting object and wire breakage have been determined, which can be used as an input signal for triggering the developed circuit. The creation of a new RPT and its use in relay protection terminals of PLT will make it possible to disable both “classic” emergency and abnormal operating modes of lines, as well as damage caused by people and objects conducting electric current approaching an unacceptable distance.

A global analysis technique is proposed to calculate the effectiveness of decoupling capacitors on practical power delivery networks (PDN). The proposed method is based on separation of a PDN into its power transmission lines (PTL) and non-PTL sections. The PTL section consists of circuit components with the highest impact on the impedance of the specified power pin, including the pin itself, the nearest capacitor and segments of PTL on both sides of the capacitor. The rest of the PDN makes up the non-PTL section which could be composed of planar shapes, PTLs or a mixture of both. The non-PTL section is characterized as a distributed circuit, preferably using an electromagnetic (EM) simulator. The effectiveness of the capacitor is measured by the self-impedance of the pin which depends on the distance between them. The pin impedance is cast in a transcendental equation in the PTL section including the impedance of the non-PTL section. The optimal placement of the capacitor is calculated using an iterative approach. With the proposed method, the use of an EM simulation at each step of the iteration is eliminated, significantly speeding up the computation process. The proposed method is validated on real-life design cases.

The peculiarities of detection using the location method of single-line-to-ground faults in the electricity transmission lines (ETLs) with 6–35 kV of tree topology and linear structures of 110 kV and higher have been studied. Ways of recognizing reflectograms if there is a fault in the ETL are presented. The investigations were carried out in laboratory settings using ETL models and under real conditions on working ETLs.

Renewable energy is generally defined as energy that is collected from resources which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves, air and geothermal heat. Renewable energy often provides energy in four important areas: electricity generation, air and water heating/cooling, transportation and rural (off- grid) energy services. With the development of power transmission in deregulated system, it becomes more and more important to control the power flow along the transmission line. The calculation of power transmission lines parameters of electric energy has a fundamental importance in the design, construction and simulation of electric power systems. This can be made in an experimental way by means of appropriate equipment for measurements of parameter on the line. This paper present theoretical and applicable circuit models for a transmission lines which focus on energy management and power-flow studies. This concentration power flow control, computation and the steady state behavior of electrical power transmission lines by implementation of FACTS devices on IEEE 3 BUS system in MATLAB/ SIMULINK package and PWS.

With the continuous growth of electricity demand, the safety and stability of transmission lines have become increasingly important. To ensure the reliability of power supply, it is essential to promptly detect and address foreign object intrusions on transmission lines, such as tree branches, kites, and balloons. Addressing the issues where foreign objects can cause power outages and severe safety accidents, as well as the inefficiency, time consumption, and labor-intensiveness of traditional manual inspection methods, especially in large-scale power transmission lines, we propose an enhanced YOLOv8-based model for detecting foreign objects. This model incorporates the Swin Transformer, AFPN (Asymptotic Feature Pyramid Network), and a novel loss function, Focal SIoU, to improve both the accuracy and real-time detection of hazards. The integration of the Swin Transformer into the YOLOv8 backbone network significantly improves feature extraction capabilities. The AFPN enhances the multi-scale feature fusion process, effectively integrating information from different levels and improving detection accuracy, especially for small and occluded objects. The introduction of the Focal SIoU loss function optimizes the model’s training process, enhancing its ability to handle hard-to-classify samples and uncertain predictions. This method achieves efficient automatic detection of foreign objects by comprehensively utilizing multi-level feature information and optimized label matching strategies. The dataset used in this study consists of images of foreign objects on power transmission lines provided by a power supply company in Jilin, China. These images were captured by drones, offering a comprehensive view of the transmission lines and enabling the collection of detailed data on various foreign objects. Experimental results show that the improved YOLOv8 network has high accuracy and recall rates in detecting foreign objects such as balloons, kites, and bird nests, while also possessing good real-time processing capabilities.

Unmanned aerial vehicles (UAVs) have become important tools for power transmission line inspection. Cameras installed on the platforms can efficiently obtain aerial images containing information about power equipment. However, most of the existing inspection systems cannot perform automatic real-time detection of transmission line components. In this paper, an automatic transmission line inspection system incorporating UAV remote sensing with binocular visual perception technology is developed to accurately detect and locate power equipment in real time. The system consists of a UAV module, embedded industrial computer, binocular visual perception module, and control and observation module. Insulators, which are key components in power transmission lines as well as fault-prone components, are selected as the detection targets. Insulator detection and spatial localization in aerial images with cluttered backgrounds are interesting but challenging tasks for an automatic transmission line inspection system. A two-stage strategy is proposed to achieve precise identification of insulators. First, candidate insulator regions are obtained based on RGB-D saliency detection. Then, the skeleton structure of candidate insulator regions is extracted. We implement a structure search to realize the final accurate detection of insulators. On the basis of insulator detection results, we further propose a real-time object spatial localization method that combines binocular stereo vision and a global positioning system (GPS). The longitude, latitude, and height of insulators are obtained through coordinate conversion based on the UAV’s real-time flight data and equipment parameters. Experiment results in the actual inspection environment (220 kV power transmission line) show that the presented system meets the requirement of robustness and accuracy of insulator detection and spatial localization in practical engineering.