Electricity Transmission Network Research Articles

Convex Relaxations of Maximal Load Delivery for Multi-Contingency Analysis of Joint Electric Power and Natural Gas Transmission Networks

Recent increases in gas-fired power generation have engendered increased interdependencies between natural gas and power transmission systems. These interdependencies have amplified existing vulnerabilities in gas and power grids, where disruptions can require the curtailment of load in one or both systems. Although typically operated independently, coordination of these systems during severe disruptions can allow for targeted delivery to lifeline services, including gas delivery for residential heating and power delivery for critical facilities. To address the challenge of estimating maximum joint network capacities under such disruptions, we consider the task of determining feasible steady-state operating points for severely damaged systems while ensuring the maximal delivery of gas and power loads simultaneously, represented mathematically as the nonconvex joint Maximal Load Delivery (MLD) problem. To increase its tractability, we present a mixed-integer convex relaxation of the MLD problem. Then, to demonstrate the relaxation’s effectiveness in determining bounds on network capacities, exact and relaxed MLD formulations are compared across various multi-contingency scenarios on nine joint networks ranging in size from 25 to 1191 nodes. The relaxation-based methodology is observed to accurately and efficiently estimate the impacts of severe joint network disruptions, often converging to the relaxed MLD problem’s globally optimal solution within ten seconds.

Identification of appropriate sites for solar-based green hydrogen production using a combination of density-based clustering, Best-Worst Method, and Spatial GIS

Hydrogen is a relatively new source of sustainable energy resources; presently, its usage ranges from direct energy generation in mixed-cycle thermal power plants to its usage in the internal combustion engine. If the generation of hydrogen is coupled with renewable energy resources, the use of hydrocarbons can be substantially reduced in both energy generation and transportation. In this paper, we conducted a national-level assessment to identify the hydrogen generation capacity of Pakistan. The methodology used in this study is a combination of spatial multi-criteria analysis and density-based clustering in a geographical information systems environment. Based on the analysis, the national clusters capable of producing green hydrogen were identified. The results shows that the hydrogen generation capacity for Pakistan is approximately 7 million tons per year using solar photovoltaic energy. The Surab-Gwadar alignment, N-25 national highway, and Quetta-to-D-I-Khan alignment offer potential hydrogen generation sites with water resources. Most of the identified sites for the production of hydrogen in the country were found to be near the national electricity transmission networks. The Best-Worst Method was further employed to provide policymakers with a road map for prioritizing the development of these capacities based on their proximity to the national networks, their terrain suitability, and their generation capacities.

Integration assessment of turquoise hydrogen in the European energy sector

Turquoise hydrogen from natural gas pyrolysis has recently emerged as a promising alternative for low-carbon hydrogen production with a high-value pure carbon by-product. However, the implications of this technology on the broader energy system are not well understood at present. To close this literature gap, this study presents an assessment of the integration of natural gas pyrolysis into a simplified European energy system. The energy system model minimizes the cost by optimizing investment and hourly dispatch of a broad range of electricity and fuel production, transmission, and storage technologies, as well as imports/exports on the global market. Norway is included as a major natural gas producer, and Germany as a major energy importer. Results reveal that pyrolysis is economically attractive at modest market shares where the carbon by-product can be sold into high-value markets for 400 €/ton. However, pyrolysis-dominated scenarios that employ methane as a hydrogen carrier also hold promise as they facilitate deep decarbonization without the need for vast expansions of international electricity, hydrogen, and CO2 transmission networks. The simplicity and security benefits of such pyrolysis-led decarbonization pathways justify the modest 11 % cost premium involved for an energy system where natural gas is the only energy trade vector. In conclusion, there is a strong case for turquoise hydrogen in future energy systems and further efforts for commercialization of natural gas pyrolysis are recommended.

Transmission Line Fault Classification Based on the Combination of Scaled Wavelet Scalograms and CNNs Using a One-Side Sensor for Data Collection.

This research focuses on leveraging wavelet transform for fault classification within electrical power transmission networks. This study meticulously examines the influence of various parameters, such as fault resistance, fault inception angle, fault location, and other essential components, on the accuracy of fault classification. We endeavor to explore the interplay between classification accuracy and the input data while assessing the efficacy of combining wavelet analysis with deep learning methodologies. The data, sourced from network recorders, including phase currents and voltages, undergo a scaled continuous wavelet transform (S-CWT) to generate scalogram images. These images are subsequently utilized as inputs for pretrained deep learning models. The experiments encompass various fault scenarios, spanning distinct fault types, locations, times, and resistance values. A remarkable feature of the proposed work is the attainment of 100% classification accuracy, obviating the need for additional algorithmic enhancements. The foundation of this achievement is the deliberate selection of the right input. The decision to employ an identical number of samples as the number of scales for the CWT emerges as a pivotal factor. This approach underpins the high accuracy and renders supplementary algorithms superfluous. Furthermore, this research underscores the versatility of this approach, showcasing its effectiveness across diverse networks and scenarios. Wavelet transform, after rigorous experimentation, emerges as a reliable tool for capturing transient fault characteristics with an optimal balance between time and frequency resolutions.

Work Domain Analysis of Electric Transmission Networks and Operation

Work Domain Analysis of Electric Transmission Networks and Operation

Vulnerability Analysis of Power Transmission Grids Subject to Cascading Failures

Cascading failures are a major threat to interconnected systems, such as electrical power transmission networks. Typically, approaches proposed for devising optimized control strategies are demonstrated with reference to a few test systems of reference (IEEE systems). However, this limits the robustness of the proposed strategies with respect to different power grid structures. Recently, this issue has been addressed by considering synthetic networks randomly generated for mimicking power transmission grids’ characteristics. These networks can be used for investigating the vulnerability of power networks to cascading failures. In this work, we propose to apply a recent algorithm for sampling random power grid topologies with realistic electrical parameters and further extend it to the random allocation of generation and load. Integration with a realistic cascade simulation tool, then, allows us to perform thorough statistical analyses of power grids with respect to their cascading failure behavior, thus offering a powerful tool for identifying the strengths and weaknesses of different grid classes. New metrics for ranking the control and mitigation effort requirements of individual cascade scenarios and/or of grid configurations are defined and computed. Finally, genetic algorithms are used to identify strategies to improve the robustness of existing power networks.

System modeling of the impact of multiple capacitor coupled substations located at different proximities on a transmission network

Electricity plays a vital role in the economy of any nation, and its availability has transformed from being a luxury to being an essential requirement. However, the implementation of conventional distribution networks in sparsely populated rural areas is often deemed economically impractical. Consequently, the exploration of alternative technologies for rural electrification becomes imperative. One such technology is the Capacitor Coupled Substation (CCS), which taps electrical power from high-voltage lines through coupling capacitors. Given that capacitors can introduce interference in an electrical system, the deployment of a CCS necessitates consideration to minimize these network disturbances. This paper modelled and analyzed the impact of multiple CCSs on the electrical transmission network, with a specific focus on the impact on the transmission line voltage when multiple CCSs are located at different proximity to one another. A typical electrical transmission network with fixed supply voltage represented as 230kVac and downstream parameters with a 230kVac and 100 kW load was selected. A system model comprising three CCSs, located at known proximities from one another, was developed using MATLAB/Simulink to simulate the network's response when one or more CCS units are connected or disconnected from the electrical transmission network. Three prototypes were also constructed to represent real-world electrical systems with different loads. The model simulation was executed while connecting and disconnecting one or more CCS at a time and at different proximities from one another within the electrical transmission network. The same procedure was repeated on the prototypes where they were connected and disconnected from the selected network. The proximity to one another was represented by different resistances which represented the electrical transmission lines between the different locations of each CCS on the electrical network. The obtained test results were subjected to comparison across three platforms: the MATLAB/Simulink model, physical prototype testing using a multimeter, and digital testing using an oscilloscope. The results showed negligible disruptions on the supply side and downstream side of the transmission network. The primary goal of this research was to provide valuable insights into the potential application of CCS technology in rural electrification by examining its impact on the transmission network. Further analysis is recommended to understand the impact of each critical component within a CCS.Capacitor Coupled Substation; Rural Electrification; System Modeling; Multiple CCS

Optimal redundancy allocations for series systems under hierarchical dependence structures

AbstractRedundancy allocations strategies are commonly used in reliability engineering to enhance the performance of reliability systems. This paper makes use the hierarchical copula to characterize the dependence structures among the components and hot/cold standbys in series systems. Optimal allocation policies of hot and cold standbys are presented for series systems with dependent components and redundancies under certain conditions imposed on the hierarchical copula as well as the components and spares reliabilities. It is shown that, under certain mild conditions imposed on the copula function and lifetimes of components and redundancies, the optimal allocations should be following the way that the resultant lifetimes for all nodes should be balanced as much as possible to enhance the system's performance. The results extend some related ones well‐known in the literature from the independent case to the dependent setting. Some numerical examples are presented as illustrations. We also present a real application in optimal allocations of redundant wires for improving the reliability of high‐voltage electricity transmission network systems.

A Methodology for Rating Electricity Transmission Lines to Assess the Most Important or Critical Lines

The proposed method, based on three combined criteria—Sn—design capacity of the power line, LF, (line flow)—power flow in an electric transmission line, MVA, and the ratio of LF/Sn—allows for ranking electric transmission lines when calculations are performed in normal/pre-emergency modes. A combined set of criteria used to study critical/post-emergency N-k modes is developed. The simulations were performed on the real Baltic 330 kV electricity transmission system. The results reveal that when the power system operates in different load modes, most of the critical power lines determined by our method fall into the actual set of important/“critical” power transmission lines. This allows us to significantly reduce the number of simulated combinations and shorten the calculation time required for it. During the study of the Baltic electricity system, it was found that the developed method was accurate and efficient and suitable for the assessment of the reliability of real electricity transmission networks when planning operational and perspective work modes. The simulations results revealed the high reliability of the Baltic electricity system. The 330 kV electricity transmission network of the Baltic countries fully meets the N-2 criterion (usually, electricity transmission networks are designed to meet the N-1 criterion).

Electric Transmission and Distribution Network Air Pollution.

There is a consensus within the scientific community regarding the effects on the environment, health, and climate of the use of renewable energy sources, which is characterized by a rate of harmful polluting emissions that is significantly lower than that typical of fossil fuels. On the other hand, this transition towards the use of more sustainable energy sources will also be characterized by an increasingly widespread electrification rate. In this work, we want to discuss whether electricity distribution and transmission networks and their main components are characterized by emissions that are potentially harmful to the environment and human health during their operational life. We will see that the scientific literature on this issue is rather limited, at least until now. However, conditions are reported in which the network directly causes or at least promotes the emissions of polluting substances into the environment. For the most part, the emissions recorded, rather than their environmental or human health impacts, are studied as part of the implementation of techniques for the early determination of faults in the network. It is probable that with the increasing electrification of energy consumption, the problem reported here will become increasingly relevant.

LEGAL OVERVIEW OF COMPENSATION FOR LAND IN THE DEVELOPMENT OF PT. PLN'S SUTET TOWER NETWORK IN THE TAKTAKAN DISTRICT OF SERANG CITY, BANTEN PROVINCE

The implementation of land compensation to the community for the construction of the Extra High Voltage Transmission Network (SUTET) by PLN falls under the Ministry of Energy and Mineral Resources (ESDM). The Ministry of Energy and Mineral Resources released Ministerial Regulation (Permen) ESDM number 13 of 2021 regarding Free Space and Minimum Clearance Distance for Electric Power Transmission Network and Compensation for Land, Buildings, and/or Plants Located in the Free Space of Electric Power Transmission Network. This regulation was enacted by Minister of ESDM Arifin Tasrif on June 17, 2021, and took effect upon its promulgation on June 17, 2021. With this regulation, the rights of the community whose land is traversed by the transmission will receive compensation. However, the regulation does not comprehensively address the impact of the development and compensation for the transmission lines of 500 kV or 150 kV, leading to injustice and legal uncertainty. PLN's responsibility for the land value of the community affected by the construction of the SUTET transmission network is limited. In providing compensation to the community whose land is traversed by the Extra High Voltage Transmission Line (SUTET), PT PLN follows existing regulations. PLN refers to Ministerial Regulation No. 01.P/47/MPE/1992 on SUTET Free Space and SUTET for Electricity Distribution Article 5 paragraph (3) concerning land for establishing support structures, including buildings and plants on that land, which must be cleared and compensated.

Physical phenomena analysis of solution structures in a nonlinear electric transmission network with dissipative elements

Physical phenomena analysis of solution structures in a nonlinear electric transmission network with dissipative elements

Optimization of SVC Placement and Capacity in the Electric Power System Transmission Networks using Multi-Objective Improved Sine Cosine Algorithm

Current technological developments are in line with the increasing consumption of electrical energy. There is a value of power losses of the electricity transmission process caused by an increase in the value of power losses, to overcome this, SVC (Static VAR Compensator) of the Flexible AC Transmission System (FACTS) can be used. From previous studies, the optimization of SVC placement in the transmission network has not been carried out to get better power losses. This research uses the Improved-Sine Cosine Algorithm (ISCA) that has a different function of r1 compared to the ordinary SCA, in which the use of the ISCA method is able to overcome the weaknesses of the SCA method. The determination of location and capacity can use more than one objective function. From the result, the optimization of SVC placement and capacity is able to reduce the value of power losses by up to 85%.

Conformable derivative in a nonlinear dispersive electrical transmission network

Conformable derivative in a nonlinear dispersive electrical transmission network

Extended Fan’s sub-ODE technique and its application to a fractional nonlinear coupled network including multicomponents — LC blocks

The present work deal with the improved Fan’s sub-ordinary differential equation (ODE) method and peruse abundant soliton solutions for a fractional nonlinear coupled network including multicomponents — LC blocks. The extended Fan’s sub-ODE technique is applied on a fractional nonlinear coupled electrical transmission network in addition — LC blocks and through some graphical representations we exhibit novelties. The integer version of the electrical circuit explored here is recently investigated but its fractional partner is weakly scrutinized. Then, we pay attention on the fractional nonlinear coupled electrical network including multicomponents — LC blocks and peruse peculiar voltage waves from the voltage wave equation governing their dynamics. The voltage waves dynamics equation is obtained by means of the Kirchhoff laws’ including the modified Riemann–Liouville derivatives. Through the fractional complex transform, we derive a nonlinear ordinary differential equation that is tackled by the suggested technique. The main gaps of the present investigation based not only on the use of the fractional version of the electrical model, but, also in the capacitor charge nonlinearity’s (the integer version used Qn,mt=C0Vn,m+b1Vn,m2, the fractional partner explored now Qn,mt=C0Vn,m+b2Vn,m3) and the proposed straightforward implemented. In addition, the technique performed here led us to discover new kind of voltage waves by using five auxiliary equation’s key parameters, more than two or three ones commonly involved into such straightforward method reported in the literature. We also prove the existence of our findings by examining the fixed points, phase portraits and related potentials according accurate electrical parameters ranges, coupling elements values wisely chosen. The current technique is reported in the present investigation in manner to be replicable to many other physical systems (electrical, mechanical, optics, acoustics to cite just a few) described by nonlinear evolution equations fractional or not.

PSO Tuning of a Second-Order Sliding-Mode Controller for Adjusting Active Standard Power Levels for Smart Inverter Applications

In recent years, due to their ability to supply electricity in isolated places where building electrical transmission networks are expensive, Microgrids (MGs) have gained much attention. A new technology called smart inverters (SIs) is currently implemented in inverter-based MGs. SIs are designed to regulate energy under given standards for connecting inverters to the grid. The closed-loop control of SIs technology is still under study and improvement due to several challenges in fields such as stability and reliability. This paper proposes a DQ control for active power regulation on a single-phase voltage source inverter (SPVSI) using a second order sliding mode control (SMC-2) for addressing the abovementioned concerns. The SMC-2 tuning is performed by a metaheuristic algorithm known as particle swarm optimization (PSO). Moreover, to simulate domestic MGs, the SPSVI operation for tracking active power values is performed by ramp rate references based on standard IEEE Std 1547-2018 for inverters connected to the grid. The SMC-2 was appropriately tuned by a PSO algorithm through MATLABTM and the system simulation through PSCADTM. The results show that the algorithm performed better compared to a classical algorithm such as proportional-integral control in terms of integral absolute error (IAE) and integral square error (ISE).

Influence of Tectonic and Geological Structure on GIC in Southern South Island, New Zealand

AbstractAs part of a 5‐year project to assess the risk posed by geomagnetically induced currents (GIC) to the New Zealand electrical transmission network, long‐period magnetotelluric (MT) measurements have been made at 62 sites in southern South Island of New Zealand, a region where there was an absence of previous MT data. The data are largely 3‐dimensional in character, but show distinct features that can be related to the known tectonic and geological structure. In this work we focus on how the measured MT impedance tensors, and a simple interpretation of conductivity structure, can be used to assess the influence of tectonic and geological structure on GIC. We use the impedance tensors to calculate the magnitudes and orientations of induced electric fields in response to various orientations of inducing magnetic field. The electric fields so calculated are then used in a simplified model of the transmission network to calculate GIC at grounded substations. Our results confirm that tectonic/geological structure in the lower South Island and the resulting electrical conductivity variations have important impacts on the GIC magnitude. In the south‐west, smaller induced electric fields, associated with the higher conductivity in that region, lead to much reduced GIC at a substation in that area. In contrast, higher electric fields occurring in a NW‐SE band across the center of the region, contribute to much larger GIC in Dunedin city. Our results thus help explain the observed GIC reported at transformers in the region.

Hybrid DGA Method for Power Transformer Faults Diagnosis Based on Evolutionary k-Means Clustering and Dissolved Gas Subsets Analysis

Considered as the heart of electrical power transmission and distribution networks, power transformers are essential part of the electricity transmission grid. Among the condition monitoring and fault diagnosis tools for these machines, dissolved gas analysis (DGA) has proven its effectiveness in their early detection and classification of faults. Up to date, many methods have been proposed in the literature for the interpretation of DGA data, classified into traditional and intelligent methods. This paper proposes a two-steps hybrid method, which uses the strengths of both methods. The approach uses the evolutionary k-means clustering algorithm based on the genetic algorithm for subset formation and subset analysis by human expertise. In the diagnostic procedure, to determine the condition of a sample, the subset to which it belongs is first identified and then the corresponding diagnostic sub-model is applied. The proposed method has been implemented with 595 DGA data, tested on 254 DGA data and validated on the International Electrotechnical Commission (IEC) TC10 database. Their performances were evaluated and compared with existing traditional, intelligent and hybrid methods. From the results obtained with the IEC TC10 database, the newly proposed approach depicts the best overall diagnosis accuracies. Indeed, the best performance is achieved with the proposed method compared to other models in the literature, with diagnostic accuracy of 98.29% compared to 88.89% of the Gouda triangle method, to 88.03% of the Hyosun Corporation gas ratio method or to 86.32% of the three ratios technique.

Mathematical modeling of chirped modulated waves along a multi-coupled nonlinear electrical transmission line with dispersive elements

This work presents a mathematical modeling of chirped modulated waves propagating along a two-dimensional nonlinear electrical transmission line consisting of nonlinear dispersive and purely nonlinear capacitive elements. Combining the rotating-wave approximation technique with the perturbation method, we derive a two-dimensional extended nonlinear Schrödinger equation with self-steepening and self-frequency shift, that predicts the formation and propagation of a very rich variety of soliton-like waves including bright, dark, kink, and double-kink soliton-like waves with nonlinear chirp in a multi-coupled nonlinear electrical transmission network with dispersive elements. Using this model equation, parameter domains are delineated in which these modulated waves exist. The parameter domains are found to be strongly dependent on the dispersive elements of the network system. Through exact solutions of the amplitude equation, we investigate the dynamics of chirped modulated waves along the network system under consideration. Our results show that the nonlinear chirp associated with each of the found soliton-like pulses is directly proportional to the wave intensity and is saturated at some finite value as the propagation coordinate approaches its asymptotic value. Also, we show that increasing the number of the network lines decreases the propagating speed of the soliton-like pulses. Most importantly, theoretical analysis show that chirping of found network pulses can be controlled by varying the self-steepening term and self-frequency shift. The validity of analytical results and the robustness of these chirped soliton-like voltage signals which may have important applications in signal processing systems are confirmed by numerical simulations. The results of our study may be launched in long distance telecommunication lines involving higher-order nonlinearities of the fiber.

Вплив інвестицій на стійкість енергетичного сектору України

Introduction. The importance of the article is determined by the need to increase the stability of the energy sector of Ukraine, the search for energy projects, the implementation of which will contribute to increasing the stability of the entire domestic energy sector. Problem Statement. In Ukraine, the energy sector is of particular importance. He ensured the vital activity of all branches of the national economy, and also made a decisive contribution to the formation of the main financial and economic indicators of the state. It is common knowledge that the stability of the energy sector, which was disrupted by hostilities initiated on the territory of the country, is one of the main elements of Ukraine's national security, which forces us to look for ways to restore it. Methods. General and special methods are used: analysis, synthesis, grouping, description, comparison, theoretical generalization, and abstract-logical. Results. It has been established that increasing the stability of the energy sector of Ukraine thanks to investments has several specific directions: investments aimed at the repair and restoration of damaged energy facilities, such as power plants, transformer substations and electricity transmission networks, contribute to the restoration of energy supply in territories affected by military actions , and ensure the provision of vital services for the population; investments to modernize and strengthen energy infrastructure, including power plants, substations and power transmission networks. The following energy projects have been identified, the implementation of which will contribute to increasing the sustainability of the entire domestic energy sector: independent energy projects created to increase the generating capacity of local energy systems; projects in transmission networks; projects in the distribution network; autonomous projects; investment in technology. Conclusions. It was concluded that, based on the current situation, in the coming years the country will either have to increase the import of energy (energy carriers), or significantly increase their generation (production), or abandon plans for economic growth and GDP growth.