Power System Elements Research Articles

Multi-period optimal power flow for identification of critical elements in a country scale high voltage power grid

The paper focuses on the identification and numerical ranking of critical elements in a power transmission network. This problem is closely linked to the identification of critical infrastructure in a power grid. A quantitative ranking of the power system elements is necessary for the prioritization of actions enhancing system resilience, as the most critical elements require higher attention ensuring protection, functionality, redundancy and reliability. The paper presents a methodological approach based on alternating current multi-period optimal power flow problem formulation and application on a reference network replicating a country scale system. The multi-period optimal power flow method was tested and applied to the reference system and a number of critical elements were identified. The paper further discusses possible protection and mitigation measures.

A Review of methodologies for Fault Location Techniques in Distribution Power System

Since recent societies become more hooked into electricity, a higher level of power supply continuity is required from power systems. The expansion of those systems makes them liable to electrical faults and several failures are raised due to totally different causes, like the lightning strike, power system element failure caused by mechanical aging as well as human mistakes. These conditions impact the stability of the power as well as lead to costly maintenance and loss of output. This article examines the latest technologies and strategies to determine the location of faults in medium voltage distribution systems. The aim is to classify and assess different strategies in order to determine the best recommended models in practice or for further improvement. Several ways to locate failures in distribution networks have therefore been established. Because faults are unpredictable, quick fault location as well as isolating are necessary to reduce the impact of faults in distribution networks as well as removing the emergency condition from the entire system. This study also includes a comprehensive evaluation of several defect location methods depending on the algorithm employed, the input, the test system, the characteristics retrieved, and the degree of complexity. In order to gain further insight into the strengths and limitations of each method and also comparative analysis is carried out. Then the main problems of the fault location methods in distribution network are briefly expounded

Utilization of Active Distribution Network Elements for Optimization of a Distribution Network Operation

Electricity Distributions Networks (DNs) are changing from a once passive to an active electric power system element. This change, driven by several European Commission Directives and Regulations in the energy sector prompts the proliferated integration of new network elements, which can actively participate in network operations if adequately utilized. This paper addresses the possibility of using these active DN elements for optimization of a time-discrete network operation in terms of minimization of power losses while ensuring other operational constraints (i.e., voltage profiles and line currents). The active elements considered within the proposed optimization procedure are distributed generation units, capable of reactive power provision; remotely controlled switches for changing the network configuration; and an on-load tap changer-equipped substation, supplying the network. The proposed procedure was tested on a model of an actual medium voltage DN. The results showed that simultaneous consideration of these active elements could reduce power losses at a considered point of operation while keeping the voltage profiles within the permitted interval. Furthermore, by performing a series of consecutive optimization procedures at a given time interval, an optimization of network operations for extended periods (e.g., days, months, or years) could also be achieved.

Power systems automation, communication, and information technologies for smart grid: A technical aspects review

Smart grid (SG) introduced proven power system, based on modernized power delivery system with introduction of advanced data-information and communication technologies (ICT). SGs include improved quality of power transmission/distribution from power generation to end-users with optimized power flow and efficiency. In addition to above modern automation, two-way communications, advanced monitoring, and control to optimize power quality issues are the classic features of SGs. This ensures the efficiency and reliability of all its interconnected power system elements against potential threats and life time cycle. By integrating ICT into the power system SGs improved the working capabilities of the utility companies. Resultant of ICT with SG leads to better management of assets and ensure energy management for end users. This review article presents the different areas of communication and information technology areas involved in SG automation.

On-Line Remaining Useful Life Estimation of Power Connectors Focused on Predictive Maintenance.

Connections are critical elements in power systems, exhibiting higher failure probability. Power connectors are considered secondary simple devices in power systems despite their key role, since a failure in one such element can lead to major issues. Thus, it is of vital interest to develop predictive maintenance approaches to minimize these issues. This paper proposes an on-line method to determine the remaining useful life (RUL) of power connectors. It is based on a simple and accurate model of the degradation with time of the electrical resistance of the connector, which only has two parameters, whose values are identified from on-line acquired data (voltage drop across the connector, electric current and temperature). The accuracy of the model presented in this paper is compared with the widely applied autoregressive integrated moving average model (ARIMA), showing enhanced performance. Next, a criterion to determine the RUL is proposed, which is based on the inflection point of the expression describing the electrical resistance degradation. This strategy allows determination of when the connector must be replaced, thus easing predictive maintenance tasks. Experimental results from seven connectors show the potential and viability of the suggested method, which can be applied to many other devices.

Improving the efficiency of the railway electric power system

The railway productivity can be increased by increasing the efficiency of the electric power system, the main elements of which are traction substations, overhead contact systems and electric locomotives. The paper analyzes the technical infrastructure of the electric power system of the railway and evaluates the energy efficiency of the equipment. To assess the energy efficiency of the system elements, the revised law of conservation of energy in the electromagnetic field, spectral analysis of electrical quantities and mathematical computer modeling of electromagnetic processes in the system are used. The proposed energy characteristics of the elements of the electric power system made it possible to determine the reasons that hinder the further development of the throughput and carrying capacity of the railway. In order to eliminate the negative impact of inductive resistance of the system elements on the energy indicators of the traction supply and the AC electric rolling stock, the feasibility of the use of high voltage DC electric traction has been proved. Through the complete and continuous use of the voltage of the electricity system for electric traction, it is possible to ensure movement in the intersubstation zone of three linked multiple trains instead of one and increase the speed of trains by 20%. Using high-voltage direct current, the efficiency of electric traction of trains can be in-creased by 7% compared to electric traction of trains using alternating current by reducing the current by 40% in the overhead contact system.

Assessment and Impact of Var Injection Devices on System Parameters

In this research work, analysis and effect of reactive power injection at different voltage level are carried out. The 39-bus test network modeled in mipower software is a part of Rajasthan power system attached with North Regional Grid of Indian Power system synchronized at 765 kV voltage level. The present problem of high load and mismanagement in providing required compensation is addressed in this paper by simulation case study. Reactive power drawl from the components end is judged and analyzed by placing fictious generator at respective voltage level. State power system area is wide, having a hierarchy voltage level varying from 765 to 33 kV, but the utilities are still unaware of obtaining possible sites and voltage level in power system network. As a result, system faces higher loading levels and unnecessary line tripping thus raising losses and reduced reliability. Pertaining to the database collected of financial year 2018–2019. Due to renewable integration the variable load behavior must be accurately known by the system engineers then only load compensation must be provided. Because presently State Load Dispatch Centers provide instructions to the substations to utilize any available compensation device available in the network to use. This paper underlines a way to access the effects on voltage profile, losses, etc. on power system elements with var support at multiple voltage levels. Case studies for real-time network are detailed, to check the observability for a load of 370 MW. The impact of practices followed is observed for the complete network.

Globally optimal phasor measurement unit placement using branch and bound algorithm

Abstract This paper presents a new global optimal Phasor Measurement Unit (PMU) placement approach based on branch and bound algorithm. The proposed technique provides the global minimum number and locations of PMUs for any power system. Different objective functions are investigated including (i) minimum number and optimum location of PMUs for full observability, and (ii) maximum system observability with specific number of PMUs (PMU Investment phasing). Moreover, the loss of a power system element or a PMU is also considered. The effects of modeling zero-injection buses and using power flow measurements on the quality of the outputs and real-time studies are presented. The proposed technique is applied to the IEEE 14-, 30-, 57- and 118-bus systems using the MATLAB platform. A comparison between the proposed technique and recently published work is held. The proposed method improves the integer linear programming accuracy, shows superiority over other techniques, and reduces the overall cost.

Assessing the Vulnerability of Power Systems Using Multilevel Programming: A Literature Review

Vulnerability studies can identify critical elements in electric power systems in order to take protective measures against possible scenarios that may result in load shedding, which can be caused by natural events or deliberate attacks. This article is a literature review on the latter kind, i.e., the interdiction problem, which assumes there is a disruptive agent whose objective is to maximize the damage to the system, while the network operator acts as a defensive agent. The non-simultaneous interaction of these two agents creates a multilevel optimization problem, and the literature has reported several interdiction models and solution methods to address it. The main contribution of this paper is presenting the considerations that should be taken into account to analyze, model, and solve the interdiction problem, including the most common solution techniques, applied methodologies, and future studies. This literature review found that most research in this area is focused on the analysis of transmission systems considering linear approximations of the network, and a few interdiction studies use an AC model of the network or directly treat distribution networks from a multilevel standpoint. Future challenges in this field include modeling and incorporating new defense options for the network operator, such as distributed generation, demand response, and the topological reconfiguration of the system.f the system.

Comprehensive design analysis of a 3D printed sensor for readiness assessment applications

PurposeThis paper aims to develop a comprehensive model of a magnetic sensor array that will be operational for a multitude of electric components in continuous and nonintrusive condition monitoring (CM) or in readiness assessment (RA) applications.Design/methodology/approachA universal nonintrusive model of a flexible antenna array is introduced to monitor and identify failures in electric machine drives. An adjustable sensor is designed to serve as a RA for a vast range of electrical elements in a typical power system by capturing the low-frequency radiated magnetic fields.FindingsThe optimal placement of the most sensitive radiated fields from several components has been discovered in this case study, enabling the detection of healthy current flow throughout. Thereafter, the short-circuit investigation, representing faulty situations, is implemented and compared with healthy cases.Practical implicationsThis sensing technique can be used for nonintrusive CM of components that are out of reach and cannot have the sensor to be held around it such as components in offshore winds, wind energy generation and power and chemical plants.Originality/valueThe results are provided for three commonly used machines with a single sensor array with numerous settings. The three dimensional (3 D) finite element analysis is applied in the structuring of the sensor, detection of the optimum location and recognition of faults in the machines. Finally, based on the setup design, 3 D printing is used for the construction of the sensor array. Thus, the sensor array with fault detection avoids major component failures and increases system reliability/resiliency.

Research on the Construction Elements of the New Generation Power System

With the massive consumption of fossil energy, the traditional power system can no longer meet the high-quality development of the economy and society and the strict requirements of the ecological environment. The whole society urgently needs to build a new generation of power system to achieve the healthy development of the economy and society under increasingly strict constraints. For the new generation of power systems, the mainstream direction is that they should promote the deep replacement of fossil energy with electric energy in the energy consumption link, and increase the proportion of electricity in the final energy consumption and clean power generation. In addition, it should also include the informatization, intelligence and digitization of the power and even energy systems, and realize the iterative optimization of the whole system with faster communication and faster computer processing technology. In this paper, Dematel analysis method was used to identify and screen the construction elements of the new generation power system. And the role of each element in the construction process was analyzed, thus the key areas in the construction of the new generation power system were clarified.

Technical and economic optimization of fuel facilities – energy complex using elements of fuzzy logic and artificial neural networks

This article discusses the possibilities of optimizing the fuel and energy complex by improving the accuracy of the forecast of the state in both the operational and medium-term periods: from an hour to several years. The model used to implement the mentioned energy efficiency improvement is based on the use of fuzzy neural networks together with the function of minimizing power losses in the elements of electric power systems. The Mamdani modification is used, which takes into account the database of previous periods of the system state, represented as static load characteristics. The organization of this approach allows you to take into account weakly formalized factors, thereby improving the quality of forecasting and dispatching management. At the same time, it is possible to use models for a wide class of objects, which is achieved due to its scalability. The estimation of forecasting accuracy of the proposed approach exceeds similar indicators of currently used statistical methods and regression implementations. These factors are direct economic drivers of reducing production costs.

A Critical Review of Demand Response Products as Resource for Ancillary Services: International Experience and Policy Recommendations

Demand response is a key element of future power systems due to its capacity to defer grid investments, improve demand participation in the market, and absorb renewable energy source variations. In this regard, demand response can play an important role in delivering ancillary services to power systems. The lack of standardization and ancillary services programs prepared for traditional generators have blocked the participation of demand in these services. Nowadays, increasing needs to ensure the security of supply, renewable fluctuations, and information and communication technology advances are boosting the interest in demand response products to deliver ancillary services. While countries have had lengthy experience with these programs, others are starting from almost zero to develop these programs. To our knowledge, no analysis or standardized comparison exists of the different parameters and prices of demand response in ancillary services among different countries. Our study reviews more than 20 power systems around the world and their programs to classify them according to standard demand response parameters. At the end of the paper we discuss the main characteristics and prices that face demand response in ancillary services markets and a series of policy recommendations to policymakers to improve the deployment on demand participation in ancillary services.

The Application of Computer Network Technology in Power Information Communication Function

Electric power communication is the key to the formation of advanced, efficient power system elements, is to maintain the normal operation conditions of power market, the premise is to ensure that the computer network security, stability, is to realize the national non-electric industry diversification, the key to enrichment, is the focus of the development of advanced, scientific power management system. In the process of rapid economic development in our country, the society is also in constant development and progress, electric power communication technology is also continuously serving and contributing to the society, and computer network is also constantly expanding in the society. In this paper, the electrical computer network is introduced, and the prospect of electrical computer network is prospected through the power communication technology.

Analysis of Control Strategies Based on Virtual Inertia for the Improvement of Frequency Stability in an Islanded Grid with Wind Generators and Battery Energy Storage Systems

Rising levels of non-synchronous generation in power systems are leading to increasing difficulties in primary frequency control. In response, there has been much research effort aimed at providing individual electronic interfaced generators with different frequency response capabilities. There is now a growing research interest in analyzing the interactions among different power system elements that include these features. This paper explores how the implementation of control strategies based on the concept of virtual inertia can help to improve frequency stability. More specifically, the work is focused on islanded systems with high share of wind generation interacting with battery energy storage systems. The paper presents a methodology for modeling a power system with virtual primary frequency control, as an aid to power system planning and operation. The methodology and its implementation are illustrated with a real case study.

Mathematical modeling of power supply reliability at low voltage quality

Purpose. Finding dependence between reliability indexes and power quality. Working out methodology for calculation of reliability index reduction depending on poor power quality based on found dependency. Methodology. The method of harmonic analysis, the principle of superposition for instantaneous power and the methods of the theory of electric machines. The research objects are distribution processes, processes of transformation, transmitting and consumption of electrical energy in power systems of 6 and 0.4 kV with non-sinusoidal voltage in it. The subjects of the research are reliability indexes of separate power supply system units and its dependency of indexes of electromagnetic compatibility. Findings. Scientific explanation of equipment reliability index reduction depending on poor power quality in power system. Detection of the effect of non-sinusoidal voltage on the reliability of transformers and cable lines. Originality. The article analyzes the problems of electricity quality at the moment and describes the importance of solving these problems. The solutions are mainly based on the change in the level of harmonics affecting the power grids, thus improving the quality of electricity. In the work, the analysis of non-sinusoidal voltage influence on power system units reliability indexes is conducted based on typical city power supply scheme. Practical value. Finding of regularities of electromagnetic processes flaws in power system units of 6 and 0.4 kV depending on non-sinusoidal voltage level. Based on researched regularities, the process of reliability index change should be described depending on power quality. The research is conducted for such power system elements as transformers and cable lines. Based on the research, the characteristics of power system units reliability index change are built depending on the load level.

System integration of processes of ensuring electric power networks safety under the conditions of impact of meteorological factors

The problem of the influence of meteorological factors on electric power networks continues to be relevant. For the safe fulfillment of their purpose, electric power networks as an element of the electric power system must guarantee the safety, stability and efficiency of the electric power supply process. To solve the above problems, it is necessary to make decisions based on meteorological observations, since the safety of electric power networks depends on the timely forecasting of meteorological factors. The study examines the possibility of system integration of the process of ensuring the safety of electric power networks and the process of monitoring meteorological factors. In order to increase the level of safety of electric power networks, it is proposed to use a geo information system that collects, processes and transfers meteorological data.

LOCAL SELF-GOVERNMENT IN THE UNIFIED SYSTEM OF PUBLIC POWER IN RUSSIA

The relevance of the study is caused by the new constitutional amendments adopted in 2020 on the unified system of public power, bodies of a unified system of public power and cooperation between state and municipal bodies. The purpose of the work is to systematically analyze the constitutional provisions and identify the place of local self-government in the unified system of public power. In this regard, we studied the stages of local self-government development as an element of the public power system, and the provisions of the Constitution of the Russian Federation consolidating the subjects of different state power levels. The authors proposed the doctrinal concepts of local self-government, a unified system of public power, and bodies of a unified system of public power.

Development of a training complex of elements of power systems and metering of electric power with application of VR technologies

The paper describes the results of simulation of virtual power equipment of a substation and an electric power metering system for the purpose of training and practicing the actions of personnel during scheduled switching and emergency situations. An experimental model is presented that demonstrates the basic functionality of the simulator, which allows for rapid switching on a virtual substation model. The virtual model will help the trained operational personnel gain operational experience, as well as eliminate the possibility of electric shock and equipment failure. Due to the flexible functionality of the program that builds the project, it is possible to implement additional blocks of the simulator, having previously tested the innovation separately from the main project. This feature guarantees compatibility of new versions of the project with the old installed versions. It also allows the client to update the product without reinstalling the program. The model was created in the Unreal Engine 4 program. This product allows you to create projects for Windows, Lunix, and Mac OS operating systems. Unreal Engine 4 is compatible with the virtual reality system. Due to compatibility, it is possible to create interactive projects, in particular, an interactive project in the field of energy.

A Novel Short-Term Load Forecasting Method by Combining the Deep Learning With Singular Spectrum Analysis

One of the major issues about the operation of power systems is the prediction of load demand. Moreover, load forecasting is of prime concern to system operators. Recently, the integration of power system elements, such as renewable energy sources, energy storages and electricity vehicle, brings more challenges, particularly when there are large fluctuations in forecasting cycle. This study concentrates on short-term load demand forecasting and proposes a hybrid method that combines Singular Spectrum Analysis (SSA) with deep-learning Neural Network (NN) techniques. In the beginning, the SSA technique is applied as an initial filter to remove noises. Next, a hybrid neural network, including Backpropagation Neural Network (BPNN) and Long Short-Term Memory (LSTM), is developed and trained. Then, the trained network is used as the core forecasting algorithm. Each SSA has different forms to combine with neural networks. The performance of the proposed forecasting algorithm is demonstrated using the power demand data recorded in Taiwan. Furthermore, this study compares the forecasting results by five models, including SSA, SSA-BPNN, ANN, SSA-LSTM, Wavelet Neural Network (WNN) and LSTM. The forecasting results reveal that the proposed forecasting model using Singular Spectrum Analysis provides the best performance on load forecasts.