Power Substations Research Articles

A framework to assess the impacts of digital electrical substations

In the context of the digital transformation of the electricity sector, the most recent technologies in power substations has promised benefits related to improved engineering, operations, and maintenance, transforming them into “smart” substations. However, methods and tools to analyse the impacts and estimate the benefits of electrical substation digitalisation to support investment decision-making have rarely been reported. We propose a comprehensive framework for assessing the impacts of the digitalisation of electrical power substations. Literature review, interviews with stakeholders and an expert survey were carried out to better understand those impacts and support the definition of the conceptual model. The framework identifies six key technological drivers and a total of 12 impacts, establishes the relationships between them, and defines key performance indicators for quantifying the impacts. The proposed framework was applied in a case study of the digital retrofit of a distribution substation on the scope of a research and development project on intelligent substations. The application demonstrates the framework's usefulness as a tool to systematically assess digital substations and highlights how digitalisation can benefit engineering and construction, and operations and maintenance activities. The proposed framework can also be applied to other contexts, thus contributing to an increasingly digital and connected electricity sector.

Design and Application of Station Power Supply System for Lithium Iron Phosphate Battery Based on Power Exchange Operation

Based on the engineering application design and development of the power supply system of lithium iron phosphate battery pack in the operation and maintenance mode, this paper conducts the application research from four aspects of battery quantity selection, capacity calculation selection, battery management system design, battery pack modular design, etc. The design scheme of the lithium iron phosphate power supply system is formulated, and the matching battery management system is designed. A universal lithium iron phosphate battery module with an “N+1” redundant configuration is developed to improve the maintenance efficiency of the battery pack. It reliably supports the substation power changing operation and maintenance mode and ensures the reliability and operation safety of the substation power supply system.

Разработка мероприятий по устранению резонансных явлений на частотах высших гармоник на линии электропередачи 35 кВ

One of the problems to ensure the quality of electricity and reliability of the network is significant deviation of the voltage curve from sinusoidal in some active electricity transmission lines of the energy system of the Irkutsk region. The purpose of the research is to develop organizational and technical measures to eliminate resonance phenomena at higher harmonics that occur in the active 35 kV electrical line connected to a traction power substation. The object of the research is non-sinusoidal mode of the 35 kV electric power transmission line connected to the medium voltage winding of the three-winding traction transformer. The authors have used technological research methods of calculation using an equivalent circuit of the existing linear circuit of an electrical power system with a traction substation. The software “Calculation program of non-symmetric and non-sinusoidal modes of the electric power system” and Microsoft Excel are used for the research. The authors have developed a 110–35–10 kV “Consumer 1 – Consumer 2 – Consumer 3” model using the software “Calculation program of non-symmetric and non-sinusoidal modes of the electric power system”. The calculation results are processed using Microsoft Excel. Non-sinusoidal electrical modes of the equivalent circuit of the electrical power system and the power transmission lines are calculated. Calculation of non-sinusoidal modes of a 35 kV line is carried out to show the distribution of higher harmonic voltages along the line. It is established that the quality indicators of electricity in terms of non-sinusoidal voltages in most nodes of the 35 kV power transmission line do not comply with GOST 32144-2013. Calculation and analysis of non-symmetric and non-sinusoidal modes of the network have shown resonance voltage increase along the line on the odd harmonics frequencies and elimination of resonance factor when installing the compensation reactor at the beginning of the 35 kV line. Based on the calculation results, the diagrams of harmonics power-voltage curve from 3 to 39 are compiled. Based on the results obtained, the authors have proposed technical measures such as installation of a compensation reactor at the beginning of the electrical power system line to prevent resonance factor to improve the electrical power quality in terms of voltage unsinusoidality in the consumers busbars connected to the 35 kV line. The proposed measures will improve the electrical power quality in busbars of consumers and satisfy the requirements of GOST 32144-2013.

Comparison of regenerative braking energy recovery of a DC third rail system under various operating conditions

Conducting simulations prior to real-world testing is essential for the planning and development of rail systems. However, accurately representing the train trajectory characteristics resulting from the railway power system and the dynamic load changes based on the train position can be challenging. The power exchange between trains and the fluctuating rail resistance between them add to the computational complexity. Given these challenges, the aim of this study is to develop a comprehensive model of DC third rail systems based on the operational requirements and parameters of the MRT Line 2 Malaysia. Moreover, the simulation method should be adaptable to investigate potential energy savings through regenerative braking systems, thereby maximizing the energy efficiency of electric railways. This study outlines the development of a framework that models the power flow within an electric rail network using a specific case study example. A simulation is presented with 15 trains operating on a double rail track to validate the model for multiple train operations. Notably, the simulation methodology developed in this research is unique compared to other approaches found in relevant literature. It integrates both the power system and train trajectory, incorporating actual system information from a practical DC third rail system to generate precise trajectory outcomes. The results show that implementing a regenerative braking energy recovery system in all traction power substations (TPSSs) has the potential to achieve significant electrical energy savings of up to 55.75% for the entire system.

Nonlinear modeling of magnetic materials for circuit simulations

Magnetic materials in the form of magnetic rings are widely used in power engineering products. In many cases, they operate in high frequency and in nonlinear conditions, e.g., as damping elements in electrical power substations equipped with Gas-Insulated Switchgear (GIS) where they provide suppression of Very Fast Transient Overvoltages (VFTOs). To model phenomena in GIS with magnetic rings it is required to have realistic time-dependent models of magnetic materials operating in a wide frequency range and nonlinear conditions. Nowadays, this has become even more relevant due to the actual trend in the industry to create digital twins of physical devices. Models composed of high-precise discrete lumped nonlinear elements are in demand in circuit simulators like SPICE. This work introduces a method based on classical algorithms that find equivalent lumped models of magnetic cores based on frequency-dependent measurements of impedance under DC-bias current. The model is specifically designed to have smooth behavior in the current domain and thanks to that to improve numerical stability in the time domain simulations.

Programming code using the Duval method for diagnosing power transformers and direct way

A transformer is a piece of equipment of great value in a public or private power substation in that it allows power to be supplied to the production processes. Thus, as it is used, the equipment is exposed to different environmental conditions such as level of contamination, salinity. , height, humidity, among others, as well as energy demand and quality, causing different types of electrical and thermal stress inside. That is why the objective of this study is to implement a programming code using the Duval method for the diagnosis of power transformers. For this, programming based on the supervised learning algorithm is used as a methodology to process the gas concentration levels contained in the dielectric oil obtained from the analysis of dissolved gases and for its interpretation the Duval method is used, which is presented in IEEE C57.104™-2019 standard. The designed code individually processes the dissolved gas analysis reports as well as large quantities of reports from the same transformer or from different ones, allowing the comparison of historical data of the equipment or equipment and the evaluation of its status according to the electrical stress to which it is subjected.

A Review on Automatic Control in Power System

Power systems are the foundation of contemporary society, providing energy for businesses, homes, and technological advancements. Precision, adaptability, and reliability are essential for these systems' complicated network of parts to satisfy the rising needs of our energy-hungry society. In this review paper, the vital function of automatic control systems in power systems is examined, along with how very important they are to maintaining stability, dependability, and sustainability. In the opening section of the essay, the basic building blocks of power systems generators, transformers, transmission lines, distribution networks, substations, and control centers are explained. The complex interactions between these components highlight how dynamic and complicated power systems are, posing several problems that need for clever control measures. Different control methods are examined, from conventional ones like proportional-integral-derivative (PID) control to cutting-edge ones like model predictive control and adaptive control methods. Each approach is evaluated for its unique benefits and innate weaknesses, providing a thorough grasp of its applicability in various operational settings. The command and control of the current power grid depends on Wide-Area Monitoring and Control (WAMS) systems, which are made possible by synchrophasor technology and reliable communication networks. Grid operators have the tools they need to maintain stability and respond quickly to emergencies thanks to their capacity to offer real-time data and improve situational awareness.

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.

An Identification Method for Irregular Components Related to Terminal Blocks in Equipment Cabinet of Power Substation.

Despite the continuous advancement of intelligent power substations, the terminal block components within equipment cabinet inspection work still often require loads of personnel. The repetitive documentary works not only lack efficiency but are also susceptible to inaccuracies introduced by substation personnel. To resolve the problem of lengthy, time-consuming inspections, a terminal block component detection and identification method is presented in this paper. The identification method is a multi-stage system that incorporates a streamlined version of You Only Look Once version 7 (YOLOv7), a fusion of YOLOv7 and differential binarization (DB), and the utilization of PaddleOCR. Firstly, the YOLOv7 Area-Oriented (YOLOv7-AO) model is developed to precisely locate the complete region of terminal blocks within substation scene images. The compact area extraction model rapidly cuts out the valid proportion of the input image. Furthermore, the DB segmentation head is integrated into the YOLOv7 model to effectively handle the densely arranged, irregularly shaped block components. To detect all the components within a target electrical cabinet of substation equipment, the YOLOv7 model with a differential binarization attention head (YOLOv7-DBAH) is proposed, integrating spatial and channel attention mechanisms. Finally, a general OCR algorithm is applied to the cropped-out instances after image distortion to match and record the component's identity information. The experimental results show that the YOLOv7-AO model reaches high detection accuracy with good portability, gaining 4.45 times faster running speed. Moreover, the terminal block component detection results show that the YOLOv7-DBAH model achieves the highest evaluation metrics, increasing the F1-score from 0.83 to 0.89 and boosting the precision to over 0.91. The proposed method achieves the goal of terminal block component identification and can be applied in practical situations.

220 kV grid optimization in Shengli Oilfield

As an important oil industry base in China, Shengli oilfield has infrastructure supporting facilities for power generation, transmission, substation, and distribution. Based on the grid data, a BPA simulation model is built for the oilfield area, and a grid optimization scheme is proposed for the problems of the existing 220 kV grid in the Shengli oilfield. The simulation results show that the safety and stability of the oilfield grid are improved under the optimized scheme, which verifies the feasibility and effectiveness of the scheme.

Hybrid Twin Simulation Technology for Training and Testing of New Generation Substation Secondary System

In this paper, a hybrid twin scheme for power substations is proposed for secondary system simulation, which can be used to support operator training and equipment testing. The proposed scheme is composed of a hardware-in-the-loop (HIL) based twin substation and a digital twin substation which can reflect the real operating status for both primary and secondary systems of a real substation. Based on the proposed scheme, the modeling method and system architecture are studied in the paper. According to the proposed hybrid twin substation, equipment testing and operator training can be conducted for new-generation secondary systems with fewer costs and security risks.

An Adaptive Battery Charging Method for the Electrification of Diesel or CNG Buses as In-Motion-Charging Trolleybuses

The decarbonization of urban bus fleets can be made by their electrification as In-Motion-Charging (IMC) buses which can run both as trolleybuses or in battery-mode. The benefit is that IMC buses can use the existing trolleygrid infrastructure where their route overlaps with it to charge the battery, and operate in battery-mode outside of it. Presently, the IMC battery charging power is set conservatively to the minimum of all the spare capacities of the traction substations found along the bus route. This can render most electrification projects techno/economically infeasible as not enough energy is picked up for the battery-mode operation and long charging times at bus terminals are required. This paper proposes then an Adaptive Charging approach that uses the locally available spare capacity under any traction substation, taking into account the limitations of the maximum substation power and the minimum line voltage. The method is proven here both theoretically and in a case study over one full year of operation of four electrified diesel/CNG bus lines in Arnhem, the Netherlands, using comprehensive and verified trolleybus and trolleygrid models. The proposed Adaptive Charging method, as opposed to the present conservative method (here, Regular Charging), is shown to make one bus electrification project completely feasible, and reduce the extra terminal charging time for the other lines by up to 64%.

A Multi-objective Optimization Planning Framework for Active Distribution System Via Reinforcement Learning

The effective planning of active distribution networks is crucial for utility companies to make informed decisions regarding investments in distributed generation, reliability assessment, reactive power planning, substation revisions, and feeder repositioning. However, the dynamic nature of the solution space makes it challenging for model-based optimization methods to ensure computational performance in active distribution network planning. To address this issue, this study proposes a planning method that focuses on improving computational performance through the continuous updating of the planning model’s solution space during the reinforcement learning training process. Based on simulations conducted on the IEEE 33-bus test system, the proposed planning strategy successfully enhances computational performance while minimizing investment costs compared to other strategies. With the proposed method, the investment cost and the operation cost are reduced by 32.42% and 23.91%, respectively.

ВИЗНАЧЕННЯ ОПОРУ ЗАЗЕМЛЮВАЛЬНИХ ПРИСТРОЇВ ПІДСТАНЦІЙ 330(220) кВ

In the electric power industry of Ukraine, the main system-forming objects are power transmission lines and substations with 330(220) kV switchgear. The most powerful sources of danger at substations are short circuits on the busbars, a direct lightning strike or the operation of overvoltage limiters and arresters.The purpose of the article is to develop a method for determining the resistance of the grounding system of substations with open switchgear 330(220) kV, aimed at increasing accuracy, taking into account the most influential independent factors. The provisions of the theory of experiment planning, the theory of electric circuits, mathematical modeling in the package Grounding 1.0, LiGro and Microsoft Excel were used to conduct the research. In the paper, a comparative analysis of the known formulas for determining the resistance of the grounding system is carried out: the formula of the GOST 12.1.30-81 standard, Ohlendorf-Laurant, Laurent and Neumann, Schwartz, Sverak formulas, as well as the formula of the international standard IEEE Std 80-2013. The results of multifactorial experiments to determine the dependence of the resistance of the grounding system on its area, the size of the grid cell, the perimeter of the cross-section of the grounding, the equivalent specific resistance of the soil, the short-circuit current and the depth of the grid location are given. A graphical comparison of the results of determining the resistance according to the considered formulas was carried out. In the paper, the method of determining the parameters of grounding system of 330(220) kV substations was further developed, aimed at ensuring standardized values of the resistance of the grounding system and the ground potential rise using formulas obtained from the results of multifactorial experiments. The results obtained in the work will make it possible to reduce the probability of damage to the insulation of 6-10 kV cables, as well as cables of secondary circuits from low-frequency and high-frequency (pulse) voltages when large currents flow into the grounding system in the mode of a single-phase short-circuit to the ground in electrical grid with a grounded neutral. References 9, tables 2, figures 6.

IoT-based monitoring and control of substations and smart grids with renewables and electric vehicles integration

The integrated renewable energy resources (RERs) based smart grid in the power distribution network (PDN) has financial and ecological benefits. However, the emergence of RER-based microgrids and substations without real-time monitoring of their power parameters leads to various challenges in the PDN, such as suboptimal resource allocation, poor load management, grid instability, and lack of real-time decision-making capabilities. To mitigate these challenges, increase the system's visibility, and make efficient decisions, intelligent monitoring and control system is required for both smart grid and power substation. This proposed study develops IoT-based monitoring and control of power substations and associated distributed smart grids to make effective decisions of integration/segregation into the PDN. The proposed IoT-based integration/segregation of smart grids and load management can mitigate the stated challenges effectively. Using the HOMER Grid®, the research also investigates the annualized power production pattern of smart grids and the power consumption pattern of integrated loads to enable proactive decisions about energy management. The proposed study implements IoT technology for power parameters monitoring of substations and smart grids for their effective use, as it considers four types of load management, including industrial, domestic, commercial, and electric vehicles, with the aid of IoT technology to avoid power fluctuations and contingencies. Effective load management has been adopted based on annualized energy consumption, load patterns and real-time monitoring, and active decisions making. The results highlight that the proposed IoT-based approach helps advance smart grid integration into the PDN and enhance energy load management, consequently reducing energy costs and suppressing carbon emissions. The validation of the proposed model is verified by the constructed prototype, where the achieved real-time monitoring and control of power substations and smart grids into PDN is performed to make effective decisions related to energy and load management. Moreover, it effectively allows power distribution companies to manage loads during high demand or crises and enhances grid stability and energy efficiency.

Determination of the electric field strength of high-voltage substations

The electric field strength is one of the main factors influencing sensitive microprocessor equipment and personnel on power stations and substations, power lines. Determining its level is an important applied task for ensuring the safe operation of electrical installations. The aim is to develop calculation relationships for determining the electric field strength created by the busbar of high-voltage substations in the working areas of personnel. The solution of the problem was based on the use of the method of equivalent charges to determine the strength of the electric field created by the complex busbar of high-voltage substations. Methodology. The development was based on solving the problem of the potential of the electric field of a point charge located in a dielectric half-space for a cylindrical coordinate system. By representing the electrode in the form of a set of point charges and subsequent integration, an expression for calculating the potential is obtained, created by a busbar of arbitrary orientation of finite length in an analytical form. Using the principle of superposition of fields and the definition of the derivative, expressions were obtained for calculating the vertical component of the electric field strength at given heights. Results. Based on the obtained expressions, using Visual Basic, the simulation of the distribution of the electric field strength under a three-phase power line with a voltage of 150 kV was performed. Comparison with the known calculation results obtained on the basis of analytical expressions for infinitely long conductors showed that the obtained expressions have an error of no more than 7%. The scientific novelty lies in the fact that for the first time expressions were obtained for determining the electric field strength created by a system of electrodes of finite length, based on the analytical method for solving differential equations. Practical significance. The proposed technique is implemented as a test module of the LiGro specialized software package, which allows modeling complex busbar systems typical for power stations and substations and power lines. A test calculation was carried out for an operating substation of regional electric networks with a voltage class of 110 kV. By comparing the duration of the calculation of switchgears with a diagonal of about 500 m, it was found that the calculation time in the LiGro complex based on the analytical method is several tens of times less than the calculation based on the finite element method. In addition, a more powerful computer was used for the end element simulation.

A site selection framework for urban power substation at micro‐scale using spatial optimization strategy and geospatial big data

AbstractThe world is facing more energy crises due to extreme weather and the rapidly growing demand for electricity. Siting new substations and optimizing the location of existing ones are necessary to address the energy crisis. The current site selection lacks consideration of spatial and temporal heterogeneity in urban power demand, which results in unreasonable energy transfer and waste, leading to power outages in some areas. Aiming to maximize the grid coverage and transformer utilization, we propose a multi‐scene micro‐scale urban substation siting framework (UrbanPS): (1) The framework uses multi‐source big data and the machine learning model to estimate fine‐scale power consumption for different scenarios; (2) the region growing algorithm is used to divide the power supply area of substations; and the (3) location set coverage problem and genetic algorithm are introduced to optimize the substation location. The UrbanPS was used to perform siting optimization of 110 kV terminal substations in Pingxiang City, Jiangxi Province. Results show that the coverage and utilization rate of the optimization results under different power consumption scenarios are close to 99%. We also found that the power can be saved by dynamic regulation of substation operation.

A Hierarchical Maintenance Method for Power System Transmission and Substation Multi-Equipment Operation Status Considering Equipment Service Age

The current conventional maintenance methods for transmission and substation operation equipment are mainly used to extract fault data features by combining micro-network algorithms to process equipment operation data. The lack of effective analysis of equipment fault characteristics leads to poor maintenance results. In this regard, a power system transmission and substation multi-device operation status hierarchical maintenance method considering the age of equipment service is proposed. By accessing the configuration network and interacting with the grid intelligent collection of data, network storage and parallel processing of data are realized. The characteristics of transmission and substation equipment operation data are analyzed and processed to build the maintenance system. In the experiments, the proposed method is validated for the effect of condition assessment. The experimental results show that when the proposed method is used to process the transmission and substation equipment, the condition assessment accuracy is high and it has a more desirable equipment maintenance performance.

Current Limiting Simulation of Magneto-biased Superconducting Fault Current Limiter (SFCL)Applied in 66 kV/10 kV Power Substation in China

The short-circuit fault currents in the large capacity transmission lines pose a challenge to the stability and safety of power system. Magneto-biased superconducting fault current limiter (MBSFCL) is with the advantages of two-stage current limiting, self-triggering and fast recovery so that it can effectively reduce the short-circuit fault current when applied to the urban power system. This paper analyzes the operation principle of MBSFCL and establishes a package type magneto-thermal coupled simulation model of MBSFCL based on MATLAB/SIMULINK. A power system model of a 66 kV/10 kV Zhang Tai Zi power substation which is in Liaoning province in China has been established and the grid-connected simulation applied MBSFCL has been achieved. Moreover, the grid-connected test is carried out, and the results of fault current, quench resistance and temperature change are obtained. The comparison of results between simulation and test verifies the accuracy of the simulation model and the application feasibility of MBSFCL.

Coordinated optimization model for solar PV systems integrated into DC distribution networks

AbstractSolar photovoltaic (PV) systems will drive deep electrification of energy systems leading to clean energy 2050. However, connecting large amounts of solar PV systems on direct current (DC) networks, like solar farms and potential future DC distribution systems, would lead to over voltages and loss of solar PV power output due to voltage issues. Further, current PV integration within distribution networks operate exclusively to maximize output using maximum power point tracking algorithms, without network coordination, which may lead to reduced solar output due to voltage issues. Here, a coordinated optimization model for solar PV systems and distribution network voltage regulators is presented. The proposed model optimally controls the settings of voltage controllers (DC‐DC converters), placed at the outputs of solar PV units and selected distribution lines, while maximizing solar power output and minimizing substation power (i.e. system losses). The solar PV systems are modelled using a trained neural network. Testing various systems against uncoordinated situations revealed that the proposed model yielded an increase in solar power of up to 60.06%, in the 28‐bus case. The proposed method will be an excellent tool enabling deep electrification using solar PV system and it overcomes limitations of uncoordinated systems used in practice today.