Transmission System Operators Research Articles

Ant-colony optimization-based multi-input multi-output (ACO-MIMO) equalization for low-complexity mode-division multiplexing (MDM) processing

In mode-division multiplexing (MDM) systems, the computational complexity of the multi-input multi-output (MIMO) equalization module is a critical obstacle to practical development. The step size μ and the number of taps K are key parameters in the equalization algorithm, influencing the performance of finite impulse response (FIR) equalizers, including convergence speed and output signal quality. To alleviate the computational burden of locating the optimal μ-K combination, we propose two ant colony optimization (ACO) -based MIMO equalization schemes: the fixed ACO-MIMO and the random ACO-MIMO, corresponding to two optimization strategies. These schemes expedite the initialization process of both parameters. Subsequently, we conduct experiments to evaluate their performance in a 3-mode recirculating-loop transmission system. Our findings demonstrate that, compared to conventional schemes, such as genetic algorithm (GA) and steepest descent algorithm (SDA), the proposed ACO-MIMO schemes significantly reduce the number of calls to the equalization algorithm for locating optimal μ-K combination by up to 42.74% and 80.63%, reducing the complexity of the whole MIMO equalization for MDM systems. And the resulting hit-rate Phit for the optimal μ-K combination reaches up to 99.34%. Moreover, the ACO-MIMO schemes exhibit stable performance across different data collected from various round-trips, confirming the robust operation for the long-haul MDM transmission. Finally, we investigate the performance disparity between the two proposed ACO-MIMO schemes through bit-error-rate (BER) distribution, concluding that under a large dataset with various BER distributions, the performance of both schemes is essentially equivalent.

Enhancing IT Infrastructure with Fiber Optics: Revolutionizing Data Flow and Beyond

Fiber optics technology has emerged as a transformative solution in modern IT infrastructure, significantly enhancing data flow and other critical aspects of digital communication. This article explores the latest advancements in fiber optics and how they can be leveraged to improve IT infrastructure. By delving into the benefits of fiber optics, such as increased bandwidth, reduced latency, and improved security, this paper highlights how these technologies can revolutionize data transmission and overall IT operations.

Coordinated voltage control for large-scale wind farms with ESS and SVG based on MPC considering wake effect

The wake effect reduces the wind speed at downstream wind turbines (WTs), making it necessary for the central controller to collect wind power generation data from each WT. However, wind farms (WFs) face a more complex problem in maintaining the voltage stability at the WT terminal while following the transmission system operator (TSO) instructions due to the information collection as well as the possible data loss during transmission. Therefore, this study proposes a coordinated control method for WTs and multiple power sources based on model predictive control under wake disturbance conditions, aiming to reduce the average voltage deviation in WT terminals and go close to the rated voltage and ensure effective compliance with TSO commands in large-scale WFs. Accordingly, the Jensen wake model was utilized to accurately calculate the available active and reactive power limits for each WT. Energy storage systems and static Var generators were modeled to coordinate and maintain the voltage in all WT terminals within the feasible range, providing peak shaving and valley filling support to reduce wind energy waste and shortfall, thereby enhancing the economic and operational reliability of WF. Further, the effectiveness of the proposed method was validated in MATLAB/Simulink.

A Review on FPGA-based Architectures for Noise Removal of Digital Images using High-Level Design

Image corruption during the acquisition and transmission operations may be caused by a variety of disturbances. Scientists are still having trouble getting rid of the noise in the original picture. picture denoising is a technique used to improve a picture's visual quality and extract small details from a damaged image. Improving an image to make it crisper than it was originally is the aim of image restoration. The field of image processing is vast. This paper presents the results of some significant work in the subject of image denoising. It looks into image denoising using some of the most recent methods, such as SEPD (Simple Edge Preserved De-noising) and RSEPD (Reduced Simple Edge Preserved De- noising).Image corruption during the acquisition and transmission operations may be caused by a variety of disturbances. Scientists are still having trouble getting rid of the noise in the original picture. picture denoising is a technique used to improve a picture's visual quality and extract small details from a damaged image. Improving an image to make it crisper than it was originally is the aim of image restoration. The field of image processing is vast. This paper presents the results of some significant work in the subject of image denoising. It looks into image denoising using some of the most recent methods, such as SEPD (Simple Edge Preserved De-noising) and RSEPD (Reduced Simple Edge Preserved De- noising). Keywords— Power consumption analysis, Digital logic circuits, Ultra-low power, Subthreshold operation, Static CMOS gates

Analyzing the boundaries for TSO-DSO coordination when activating flexibility for DSO´s in networks with an expected significant load increase

The Transmission System Operators (TSO) and Distribution System Operators (DSO) coordination literature deals with different coordination schemes or coordination methodologies. However, consumer actions or regular DSO operations continuously affect the system balance operation, and no major coordination is required as these actions individually have negligible impacts on the overall system. The literature has not previously analysed where the limit beyond which coordination is necessary. This question requires an analysis of the DSO operations where the need for coordination is foreseen and a case-by-case study of what type of impacts are created by the activation of the DSO flexibility resources on the responsibilities of the TSO. Such analysis helps to define thresholds and scenarios considering existing changes in distribution networks, which can be a reference for delimitating costly coordination procedures. This paper presents a revision of all the possible scenarios of the DSO operation needs and their impacts on TSO responsibilities considering the possible TSO/DSO borders at different voltage levels. Afterward, a methodology is proposed to analyse more deeply the impact of flexibility activation with an expected significant load increase. Representative case studies evaluate the possible impacts on TSO responsibilities of local flexibility activation. This paper concludes that the impact of local flexibility is expected to be significant when large power changes are managed in the short term, estimated in more than 50 MW if the DSO operates in 132 kV or more than 15 MW if the DSO operates up to 66 kV. At LV or MV level, minor coordination would be needed.

Levers and obstacles for implementing public engagement practices in electricity grid development

The scale of change required through the development of new energy infrastructure throughout Europe is vast. The societal dimensions of the energy transition are increasingly recognised as centrally important and approaches to infrastructure development which seek to incorporate such considerations are warranted. EirGrid - Ireland's national electricity transmission operator - through their own historical context, have undergone a journey to develop new strategies for citizen and community engagement with relation to energy grid developments.Here, we reflect upon this journey, situating it within their previous failures and the national context. This process of reflective practice seeks to provide findings for other organisations internationally undertaking a journey towards establishing new engagement practices. The establishment of such practices is critical for enabling deeper societal engagement on the energy transition. A research gap exists in relation to the organisational development of new public engagement practices within institutions tasked with developing infrastructure associated with the energy transition. This creates a challenge whereby ever-increasing calls for public engagement are made, but no lessons exist with relation to how such new practices can be embedded within an organisational strategy. We contribute to this space through answering the research question: what are the key levers and barriers for organisation change towards new forms of public engagement in infrastructure delivery?The reflections outlined through this paper have been provided by individuals in different positions across the organisation. The paper develops key findings which add to the literature in relation to levers and obstacles for implementing public engagement and associated factors.

Strategic behavior in TSO-DSO coordinated flexibility markets: A Nash equilibrium and efficiency analysis

This paper investigates the way in which the design of a TSO-DSO coordinated flexibility market can enable strategic behavior by flexibility service providers (FSPs). Multiple flexibility market models are considered for the procurement of flexibility services by transmission and distribution system operators, namely: a common (joint) market, a fragmented market, and a sequential multi-level market. Considering these market models, three non-cooperative games are introduced to investigate the strategic bidding and interaction between FSPs therein. Detailed conclusions are then drawn on the existence and uniqueness of Nash Equilibria (NEs) in the developed games, including derivations of closed-form expressions of the resulting NEs and corresponding price-of-anarchy, capturing the FSPs’ strategic bidding impact on the markets’ efficiency. The analysis considers – first in a duopoly setting, then with multiple players – three different use cases representing when: (1) a sufficient flexible capacity exists (sufficient flexibility offered from the FSPs and adequate interconnection/grid capacity between systems); (2) participants have a scarce flexibility capacity; and (3) a restrictive interface capacity exists between the systems. A case study considering an interconnected transmission–distribution system and multiple FSPs corroborates the analytical findings. The obtained results show that market participants have incentives to set bid prices greater than their marginal costs, thus decreasing the markets’ efficiency. This aspect is shown to be more pronounced when the available flexible capacity is limited, a restrictive line limit is present, or when the market is fragmented, thus supporting the need for additional network investments and the creation of joint flexibility market formats.

TSO-DSO interface for Net Zero: the German case of 50Hertz and its DSO neighbour TEN Thüringer Energienetz*

As Germany advances towards its energy transition goals, the imperative to expand and restructure its power grid infrastructure becomes increasingly evident. The current infrastructure lacks the capacity to meet future demands, highlighting the pressing need for action. Escalating challenges related to system security and grid reliability underscore the critical importance of fostering close coordination between Distribution System Operators (DSOs) and Transmission System Operators (TSOs). Collaboration is particularly crucial in control areas such as for instance 50Hertz’s in north-eastern Germany, where efficient management of energy fluctuations is essential for the successful transition to high renewable energy usage. Regulatory strategies aimed at facilitating this transition must prioritize a strong collaboration between DSOs and TSOs necessary for stability, optimizing operations, and securing the network. This article is intended to illustrate how a regulatory framework for such TSO-DSO cooperation in north-eastern and eastern Germany for congestion management could be necessary, in accordance with the next grid development plans. Regulatory gaps associated with such interface will be identified and policy recommendations derived from them will address the challenges and opportunities linked to congestion management and the utilization of smart grid technologies.

Hybrid strategy of flexibility regulation and economic energy management in the power system including renewable energy hubs based on coordination of transmission and distribution system operators

Energy management of energy hubs in the power system impacts both transmission and distribution networks and their operations. Hence, to enhance efficiency, there should be bilateral coordination between distribution and transmission networks. Moreover, thanks to including power sources, storage, and responsive loads, hubs can earn financial benefits from the energy and ancillary services market. Therefore, this paper presents the operation of distribution and transmission networks in the presence of flexible-renewable energy hubs based on transmission system operator (TSO)-distribution system operator (DSO) coordination according to the market clearing price modeling in energy and flexibility markets. The proposed scheme minimizes the sum of the expected operating costs of the networks and hubs minus the expected flexibility profit of the hubs. The scheme is constrained to optimal power flow equations of the networks, flexibility limit of the networks, and flexibility-operation model of renewable energy hubs located in transmission and distribution networks. The unscented transformation method is used to model the uncertainties of load, renewable sources, and stationary storage (aggregation of electric vehicles). Energy price and flexibility are among the dual variables of the problem. To simultaneously calculate these variables and the main variables of the problem, an integrated model of the suggested scheme based on the penalty function technique is extracted. Eventually, numerical results validate the capability of the scheme in enhancing the operation, economic, and flexibility status of the proposed scheme, in which renewable sources along with storage and responsive load in the energy hub can obtain 100 % flexibility conditions for the networks. They help enhance the economic and operation indices of distribution and transmission networks by about 26 %-44 % and 22 %-33 % compared to the case without hubs and renewable sources.

Energy Efficient strategy for Wireless Sensor Networks lifetime endurance using Genetic Algorithm

This study propose an optimized routing scheme for multiple hops Wireless Sensor Networks to enhance the lifetime of the network. Since the wireless sensor networks work as application-centric having the capabilities of data gathering and transmission to the base station. Therefore, a significant amount of sensor networks` energy spends during such operation of data collection and transmission if the route is not optimized. So, a meta-heuristic genetic algorithm plays a vital role in finding the optimized route. We will modify the genetic algorithm for better optimization results so that the best route can be selected among all possible routes and will save the wireless sensor networks` energy. All information is routed towards the sink via intermediate neighbor nodes, which only relay the data without performing any computation or operation. The genetic algorithm determines the route information to all nodes and sinks. Then, the data takes the most optimal route for data transmission. Thus, this study proved a considerably saved extra waste of energy.

Production or transmission investments? A comparative analysis

AbstractThe European electricity market is moving towards an integration process, and to facilitate that integration and the flow of electricity in that market, the European Transmission System Operator proposes different investments in transmission and production capacities. I develop a model of imperfect competition to study those investments, and I identify the economic forces that determine the equilibrium price and the flow of electricity: The size and the competitive effects. I prove formally when those forces operate simultaneously or independently, and how they determine consumers’ surplus and suppliers’ profits. I prove that an investment in transmission capacity outperforms an investment in production capacity by maximizing consumers’ welfare, but the performance in terms of suppliers’ profits is ambiguous.

Planning natural gas supply chain pathways for energy system decarbonisation: An Australian case study

The future role of natural gas systems in a deeply decarbonised world is very uncertain. This work seeks to characterise the changes that the clean energy transition is likely to induce in the natural gas chain, across extraction and transmission, distribution networks and gas consumption/use trends, for various scenarios with different demand and supply drivers. First, the results of a least-cost macro-scale energy system planning optimisation are explored to identify future natural gas demand and supply requirements. Second, those findings are used as inputs to a detailed analysis of the full gas supply chain, from extraction to final use, to examine the evolution of i) stored resource levels; ii) transmission and distribution networks operation and financing; and iii) required capacity and siting of gas generation; all, with a realistic account of the related infrastructure. Australia is investigated as a case study that relies on natural gas for both domestic and export purposes. Results project a shift towards a more localised gas consumption to be largely supplied by fewer basins, with associated potential transmission and extraction bottlenecks. They anticipate an overall less utilised, ageing distribution network with potential challenges to asset reliability and financing. Finally, they demonstrate both the scheduled and early retirement of fossil generation assets can allow the siting of considerable amounts of new gas power firming capacity on brownfield sites, thus offering an opportunity to reduce total system costs.

ID-Det: Insulator Burst Defect Detection from UAV Inspection Imagery of Power Transmission Facilities

The global rise in electricity demand necessitates extensive transmission infrastructure, where insulators play a critical role in ensuring the safe operation of power transmission systems. However, insulators are susceptible to burst defects, which can compromise system safety. To address this issue, we propose an insulator defect detection framework, ID-Det, which comprises two main components, i.e., the Insulator Segmentation Network (ISNet) and the Insulator Burst Detector (IBD). (1) ISNet incorporates a novel Insulator Clipping Module (ICM), enhancing insulator segmentation performance. (2) IBD leverages corner extraction methods and the periodic distribution characteristics of corners, facilitating the extraction of key corners on the insulator mask and accurate localization of burst defects. Additionally, we construct an Insulator Defect Dataset (ID Dataset) consisting of 1614 insulator images. Experiments on this dataset demonstrate that ID-Det achieves an accuracy of 97.38%, a precision of 97.38%, and a recall rate of 94.56%, outperforming general defect detection methods with a 4.33% increase in accuracy, a 5.26% increase in precision, and a 2.364% increase in recall. ISNet also shows a 27.2% improvement in Average Precision (AP) compared to the baseline. These results indicate that ID-Det has significant potential for practical application in power inspection.

Time-domain equivalent model for harmonic simulations of wind and photovoltaic plants

Equivalent models of wind power plants or photovoltaic systems reduce the computational burden relative to detailed models (DMs) during power quality studies. However, existing time-domain equivalent models are ineffective for predicting harmonic currents because they do not consider switching behavior from power converters. This paper proposes a novel time-domain equivalent model, the aggregated harmonic model (AHM), to perform harmonic current prediction in large plants. The AHM uses the National Renewable Energy Laboratory method to equalize the collector system and applies the superposition principle to include the dead time and switching effects. Simulations were executed using the DM and AHM of actual plants. Field measurements were performed to validate the AHM. The results show that the proposed model produced well-matched curves for current waveforms, frequency responses, and harmonic spectra. Consequently, this model is an accurate tool for transmission system operators.

Cyber-Physical Modeling and Vulnerability Assessment of Substations for Transmission System Operator

In bulk power systems, the majority of interaction between cyber and physical components takes place in substations. However, in most of the cyber–physical power system models the physical layer is typically done using the bus-branch (BB) model, where each substation is considered as a single node. This approach will not capture the details of the cyber layer. This paper proposes a framework to model the substations using node-breaker (NB) models for physical system representation so that the detailed station configurations, the current and the voltage transformer positions, arrangements of protective relays, bay control units and associated communication infrastructure within the substations and its dependencies on the physical elements can be captured effectively using a single cyber–physical graph. Keeping a transmission system operator in view, who does not use power flow and security assessment tools for station operations and maintenance, a vulnerability assessment approach is proposed to assess the risk using some representative attack scenarios. The proposed approach is demonstrated using WECC 3-machine system for breaker and half station configuration. The attack scenarios are developed based on the real substation configuration and the adversary’s ability to understand the substation protection and BI/BO operations.

Solar energy generation from residential buildings, transition of the energy sector from fossils to carbon-free energy and meeting UN SDG

Purpose This study aims to focus on the transition of Kosovo’s energy generation sector from fossil fuels (94%), to renewable sources. The installation of 10 kW photovoltaic (PV) panels in individual houses will mitigate CO2 emissions from electrical energy generation and contribute meeting the sustainable development goals (SDGs; 7, 11 and 13) set by United Nations General Assembly. This study case is based on the installation of PV panels on the roofs, and where possible on the facades of the private residential buildings in seven, the most populated towns of Kosovo (Prishtina, Prizren, Mitrovica, Peja, Gjakova, Ferizaj and Gjilan). Design/methodology/approach This study used the data, in regard to direct normal irradiation, altitude, coordinates, PV system configurations, specific PV power output and optimum tilt of PV panels specific for the selected locations,retrieved from Global Solar Atlas, which is a web-based-tool, as provided by “Solargis,”a company that provides online and commercial solar data resources, selected by The World Bank and the International Finance Corporation. The second software was RETScreen Expert, which is more sophisticated and allows input of more variables with regard to the proposed 10 kW PV system. With the use of RETScreen Expert software, the financial viability of the project, the equity payback period, and the reduction in greenhouse gas (GHG) emissions compared to the base case were assessed. Based on the gained data, the feasibility and outcome of the study case were assessed in terms of power generation, cost and comparison with the present PV installed capacities in Kosovo. Findings Small-scale solar energy generated from individual buildings can make great impact of country’s policies toward lowering CO2 emission as one most influential greenhouse gas in rising average global temperature, improving air quality in towns by lowering emission of harmful gases and particulate matter (PM). As the study foresees installation of 10 kW of PV in residential houses, the calculated yearly energy generation would be around 15 MWh, which is twice of the average of real consumption of a household in Kosovo. This calculated energy generation from private houses is equal in capacity with generation of present PV parks that are connected on grid as reported from Transmission, System and Market Operator of the Republic of Kosovo. This proves that, if implemented, the study outcome would make Kosovo to meet the goal for a carbon free energy and meeting targets of at least three out of 17 SDG set by UNSC. Originality/value This paper’s model provides a ground for a transition of national energy sector from 90% fossils dependence to renewable energy sources (RES). Despite of some barriers such as cost of initial investment, energy storage, lack of government’s incentives and legislative base for households to become prosumer or at best energy self-sufficient buildings, this solution will make Kosovo harness its unused RES and meet targets of Paris Climate Agreement for net zero CO2 emissions from energy production by 2050 and SDG targets.

Maximizing social welfare in local flexibility markets by integrating the value of flexibility loss (VOFL)

The increasing integration of Renewable Energy Sources (RESs) poses challenges due to their unpredictable nature. To address these challenges, flexible Distributed Energy Resources (DERs), such as Distributed Generators (DGs), Flexible Loads (FLs), and Energy Storage Systems (ESSs), have emerged in distribution networks. This paper proposes a linear programming formulation for optimizing flexibility provision in the Local Flexibility Market (LFM) to maximize Social Welfare (SW), contrasting with existing literature. The concept of the Value of Flexibility Loss (VOFL) is introduced to enable the Distribution System Operator (DSO) to optimize flexibility procurement, ensuring economic profitability for both providers and consumers. Additionally, the DSO can interchange flexibility with the Transmission System Operator (TSO) based on economic incentives. Numerical results demonstrate the accuracy and efficiency of the proposed model.

Intelligent alarm flood management for power systems

Alarm floods pose a challenge to the successful operation of transmission and distribution systems because the alarm rate is often higher than what operators can effectively manage. Such a high volume of alarms can distract operators from unrelated but relevant alarms that occurred during the flood. To mitigate this situation, we propose a method to group alarm floods into clusters and identify additional alarms that might be lost in the flood and ignored by the operator. To do so, three different clustering approaches are introduced and tested using historical alarm data from a transmission system operator (TSO). Importantly, the results are validated by the end user highlighting the applicability of the proposed alarm flood management tool in real world scenarios.

Real-time coordination of integrated transmission and distribution systems: Flexibility modeling and distributed NMPC scheduling

This paper proposes a real-time distributed operational architecture to coordinate integrated transmission and distribution systems (ITD). At the distribution system level, the distribution system operator (DSO) calculates the aggregated flexibility of all controllable devices by power-energy envelopes and provides them to the transmission system operator (TSO). At the transmission system level, a distributed nonlinear model predictive control (nmpc) approach is proposed to coordinate the economic dispatch of multiple TSOs, considering the aggregated flexibility of all distribution systems. The subproblems of the proposed approach are associated with different TSOs and individual time periods. In addition, the aggregated flexibility of controllable devices in distribution networks is encapsulated, re-calculated, and communicated through the power-energy envelopes, facilitating a reduction in computational complexity and eliminating redundant information exchanges between TSOs and DSOs, thereby enhancing privacy and security. The framework’s effectiveness and applicability in real-world scenarios are validated through simulated operational scenarios on a summer day in Germany, highlighting its robustness in the face of significant prediction mismatches due to severe weather conditions.

Can we compute the worst voltage case under power flows uncertainty at TSO-DSO interfaces?

This paper proposes the new problem of calculating the worst-voltage-case (WVC) under power flows uncertainty, particularly at interfaces between transmission and distribution grid operators. The goal of the calculation is to verify if the realization of the worst uncertainty scenario leads to abnormal voltages, or assure where the voltage instability is not a risk, and inform the transmission system operator. The problem is formulated as a tailored non-convex, nonlinear optimal power flow (OPF) with complementarity or equilibrium constraints (ECs). The latter model the generator switch between under voltage control and under reactive power limit. The problem is converted into a mathematically equivalent nonlinear programming OPF problem in which ECs are handled as penalty terms in the objective function. The paper has conducted a series of experiments on the 60-bus Nordic system, which have pointed out the challenges associated to such computations to obtain meaningful results and unveiled new insights. The findings and scalability are confirmed using a real-world 1203-bus system.