Electric Power System Analysis Research Articles

Dynamic stability analysis of the aircraft electrical power system in the more electric aircraft concept

This paper presents the modelling and analysis process of the electrical power management system on board an electrified aircraft conforming to the More/All Electric Aircraft concept. The main objective of the study is to assess the stability of the Electric Power Distribution System under different operational conditions, including the aspect of constant power loads. The paper describes the structure of the system, in which the key role is played by a synchronous generator and a three-phase rectifier converting alternating current AC into direct current DC. To solve the problem, modeling methods in the Matlab/Simulink environment were used, which enabled the analysis of the dynamic properties of the system and the assessment of stability under various types of loads. The obtained test results show that the presence of constant power loads can lead to instability in the EPDS system, manifested by voltage and current oscillations exceeding the standards specified in the MIL-STD-704E standard. The paper also provides tools for predicting system stability without the need to conduct full stability tests, which is important for the design of modern aviation power systems. The final section of the work presents the research results obtained and the resulting significant insights and practical conclusions.

I-CNN-LSTM: An Improved CNN-LSTM for Transient Stability Analysis of More Electric Aircraft Power Systems

I-CNN-LSTM: An Improved CNN-LSTM for Transient Stability Analysis of More Electric Aircraft Power Systems

Composite reliability analysis of electric power systems considering climatic and spatial conditions using self-organizing map

This article presents an innovative approach by integrating different models that represent the failure rates of components related to weather events, considering the geographic location and its variation over time, to a customized Monte Carlo simulation model to ensure the draw synchronized with the load and generation curves, and then quantify the impact of these events through the power flow. The study focuses on using a neural network is trained to classify/filter system states in order to reduce the need for electrical studies and speed up the reliability assessment process. The approach is demonstrated with reference to the IEEE-RTS network test case. The results obtained indicate that the inclusion of renewable sources and climatic conditions have a significant impact on reliability indicators, as failure rates subject to these meteorological conditions tend to increase, providing a greater risk of simultaneous shutdowns, and contributing to the worsening of the system severity index. Therefore, the proposed model allows for a faster and more realistic reliability assessment, directing the planning of expansions and reinforcements and allowing risk monitoring during system operation.

Ecological network analysis and optimization of resilience and efficiency for electric power systems design

The simultaneous increase in natural disasters and human dependence on critical infrastructures for essential services such as water, electricity, etc., places ever-increasing demands on the reliable, safe, resilient design and operation of these infrastructures, with a trade-off between continuity of supply (safety and resilience) and quality of supply (reliability and efficiency) at limited cost. With this in mind, a new methodology for the analysis of electric power systems inspired by natural ecosystems is proposed here and applied to representative systems from literature. Information theory is used to quantify the results of the ecological network analysis (ENA) performed. The analysis shows that electric power systems are more efficient than reliable and vulnerable to disasters. A flow matrix is constructed from the available IEEE systems data, quantified and analyzed using information theory, and finally validated by contingency analysis and SCOPF analysis. The original network configurations are compared to random generated topologies. Comparisons are also made with ENA-inspired configurations. The latter show significantly fewer violations in each contingency scenario compared to the original configurations, further supporting the use of ENA to balance power system efficiency and resilience. Thus, ENA can be used to develop power systems with balanced efficiency and resilience.

Efficiency evaluation and productivity analysis of complex electric power systems in China: A directional slacks-based network data envelopment analysis approach

The paper introduces a robust methodology for evaluating complex electricity system efficiency, making several contributions. It systematically decomposes the electric power system into various processes, including power generation, transmission, distribution, and power consumption, with parallel sub-processes for production and domestic power consumption. Employing data envelopment analysis (DEA), the paper develops a network directional slacks-based (DSB) model to evaluate the whole system and the internal processes. The model is theoretically proven to be feasible, providing efficiency scores and identifying inefficiencies in the system and its processes. A noteworthy addition is the introduction of the DSB green Luenberger productivity index and its decomposition, offering an analysis of productivity changes in electricity systems. Empirical analysis covering 30 Chinese provinces from 2013 to 2019 uncovers the performance variations among provinces and processes, pointing out inefficiencies and changes in technology and efficiency over time. The empirical findings aim to support efforts in enhancing the overall efficiency of China’s interprovincial power system.

Application of noise-filtering techniques to data-driven analysis of electric power systems based on higher-order dynamic mode decomposition

A transition to renewable energy is increasing the long-distance export of power, with reduced spinning inertia and small stability margins. In this work, we apply higher-order variants of a data-driven technique, the dynamic mode decomposition (DMD), for stability analysis and short-term prediction of power systems with renewable sources of energy. In the present paper we study the sampling duration for extraction of physically relevant dynamics suitable for prediction using noisy historical measurements of power system disturbance events. Trends in behaviour of the dominant mode are studied to estimate the singular value threshold and the delay embedding for prediction. In a sampling window around ten times the dominant periodic interval, the higher-order Kalman filtering DMD and extended Kalman filtering DMD (filtering for system identification) are newly applied to predict an historical resonance and a possible near-resonance events of single dominant frequency. In turn, multiple frequencies of a wide-area oscillatory disturbance with low-level non-Gaussian noise are best captured and predicted using the total-least-squares higher-order DMD.

Analysis of a Balanced Short Circuit on a Sulbagsel Electrical System by Using The FFA-ABC Method Approach

Fault studies are an important part of electrical power system analysis. The purpose of this study was to determine the amount of line current at the point of disturbance when a three-phase balanced fault occurs in the real Sulbagsel electrical system. In this paper, a new hybrid FFA-ABC (Fruit Fly Algorithm-Artificial Bee Colony) method is proposed, which is one of the new methods used to calculate balanced three-phase short circuit currents in electric power systems, especially in the real Sulbagsel electrical system of South Sulawesi, Indonesia. The real electricity system of Sulbagsel was chosen as the research object because this system consists of 15 generators, 44 buses, 52 transmission lines, and 29 load buses with system voltages varying from 30 kV, 70 kV, 150 kV, and 275 kV so that this system is included in the complex system category. To test the effectiveness of the proposed FFA-ABC method, it was implemented on a real electric power system, namely the Sulbagsel System. In addition, it can also be applied to IEEE electrical systems or other real electric power systems. The results of the new hybrid FFA-ABC method of the balanced short circuit analysis of the Sulbagsel electrical system are then compared using the FFA method, the ABC method, and the deterministic method (in this case, the bus impedance matrix (BIM) method). The simulation results obtained show that the FFA-ABC hybrid method is able to solve the problem of balanced short circuit analysis in the Sulbagsel electrical system in South Sulawesi, Indonesia which the largest fault current occurs when the fault is close to the slack bus generator (bus 2=Sidrap) of 18.9697 p.u, and the smallest fault current occurs when the fault is farthest from the slack bus generator (bus 44=Poso) of 0.8457 p.u.

A universal model of three-phase asynchronous motors for electrical power system analysis

<p><span lang="EN-US">The high incidence of three-phase asynchronous motors (TAM) in global energy consumption and its influence on the operation of electrical systems makes it necessary to develop models that allow their analysis effectively. Based on this, this paper presents a universal model of TAM based on the relationship between the active and reactive power of the TAM and the deviation of voltage and frequency. It can be applied to any general-purpose TAM and is very useful when representing these motors in electrical power system studies. The model parameters were obtained from a statistical analysis performed on 70 TAM of different classifications. The results are validated by comparing them with those obtained from the solution of the equivalent circuit, demonstrating its validity by less than 6% errors.</span></p>

About the Planned Reliability of Electric Power Systems

The article discusses the issue of expanding the methodological foundations of system reliability of electric power systems as part of the development of a new type of system reliability - planned reliability. Planned reliability is a type of system reliability intended for the analysis of electric power systems when planning their operation for a period of up to 1-2 years. Planned reliability includes some signs of security and adequacy. The need for the development of methodological foundations for this type of system reliability is associated with the need to solve a number of important problems in electric power systems, such as planning repairs of power equipment, long-term planning of power system modes, etc.

Reliability Assessment Based on Optimal DGs Planning in the Distribution Systems

Due to increased load demands, distribution systems suffer from high power losses, low voltage levels, high current, and low reliability. To solve these problems, integrate distributed generator units (DG) into the distribution system. DG units are among the most popular methods of improving distribution system reliability, power losses, and bus voltage improvement through the placement and selection of distributed generator units in an optimal location and size. This work proposed Enhanced Particle Swarm Optimization (EPSO) technology to find the optimum location and size of DG units to reduce power losses, improve bus voltage level, and employed the Transient Electricity Analyzer (ETAP) to evaluate the reliability of the distribution system network. ETAP is a programming tool for modeling, analysis, design, optimization, operation, and control of electrical power systems. These findings may be useful in conducting reliability assessments and correctly utilizing dispersed generation sources for future power system growth by power utilities and power producer companies. The proposed method was employed on the Iraqi distribution system (AL-Abasia distribution network (F10 feeder)). After adding three DG units to the distribution system, theer adding three DG units to the distribution system, the obtained simulation results showed a significant reduction in power losses, voltage levels, and reliability enhancement.

PanSuite: A free simulation environment for the analysis of hybrid electrical power systems

In many engineering domains, complex systems are composed of several interconnected and interacting parts that are modeled and analyzed in different ways. This is the case, for instance, of modern power systems, which are commonly labeled as “hybrid” for this very reason. This heterogeneity has triggered the development of numerical tools capable of simulating the different parts making up a hybrid system. Often, however, these tools either tackle a very specific aspect of power systems analysis (e.g., power flow computation), or are composed of interacting parts that rely on heuristics for their correct functioning. In this paper we describe pan, a free simulator developed in our group combining very high numerical efficiency with a vast choice of simulation algorithms suited for power system analysis. We also introduce three recently developed open-source interfaces to panwritten in the MATLAB, Python, and Juliaprogramming languages, which greatly reduce development times and allow the user to incorporate power system analysis into extended simulation and analysis workflows. Together, these tools make up pansuite.

An analytical review for the power system of a spacecraft

Electrical bus is needed for the operation of all active spacecraft systems and subsystems. In the spacecraft mechanism, the battery charging system and the bus storage continued with bus control, the conditioning and bus distribution is an essential part for keeping the spacecraft in working mode. In this paper, the discussion for electrical power system (EPS) analysis in the spacecraft body will be elaborated from the previous research papers on this subject covering the topics of solar array, solar array drive, over current and over voltage protection, battery charging and discharging, bus control, conversion.

Comparison of Radial and Zonal DC Distribution System for Hybrid-Powered Trimaran Vessels Power Flow Analysis

Two types of power grid structures have been applied to the shipboard, namely the radial and the zonal networks. These two distribution systems have different power characteristics transmitted to the bus panel. The power characteristics affect the power density of each bus at each level. This paper explores the power characteristics of the radial type and the zonal type power grid structures in a DC distribution system. The power flow of both distribution system types has been determined by the Adaptive Newton-Raphson method and simulated based on ship operation conditions using Electrical Power System Analysis Software (ETAP). In determining the power flow for the DC distribution system, one-line diagram modelling is developed in radial type and zonal type. The simulation parameters are adjusted to the operating conditions of the ship, namely sailing, manoeuvring, loading-unloading, and at the port. After that, a power flow simulation has been carried out using ETAP and has showed what had successfully implemented the power flow in the DC distribution system for radial and zonal types. The capacity of Power generation is adequate all through a ship operation. The characteristics of the transmitted power show that the zonal type has a higher efficiency rate than the radial type. The zonal type has a backup bus so that the electrical system's reliability is higher than the radial type. However, the power distributed to the equipment bus from the load bus, both the radial type and the zone type, has the exact power requirements.

Seismic Vulnerability Assessment of Thermal Power Plants Based on Beta Function

The study on seismic vulnerability of thermal power plants is of great significance for seismic damage prevention of the electrical power system and risk analysis of seismic economic loss. This paper presented a study method for obtaining the seismic vulnerability matrix and vulnerability curve of thermal power plants based on beta function. Firstly, according to the study results of thermal power plants in American ATC-25 report, the expected values of seismic damage indexes of thermal power plants under different seismic intensities were calculated. It was assumed that the expected values of seismic damage indexes of substation and thermal power plant were the same, and the dispersion of distribution of seismic damage indexes was the same. Then, based on the actual seismic vulnerability matrix of substations obtained from statistics in Wenchuan earthquake, the seismic vulnerability matrix of thermal power plants under different seismic intensities was fitted by using the probability density function of beta distribution. Finally, the seismic vulnerability curve of the thermal power plant based on peak ground acceleration (PGA) was obtained by using the cumulative function curve of standard lognormal distribution. The calculation results show that the seismic damage ratio calculated from the seismic vulnerability matrix of thermal power plants is basically consistent with the seismic damage ratio in ATC-25 report.

A Methodology for the Comparative Analysis of Hybrid Electric and All-Electric Power Systems for Urban Air Mobility

The present investigation addresses the topic of Urban Air Mobility with particular reference to the air-taxi service with electrified power systems. A new and detailed methodology is proposed for the simplified design and energy analysis of conventional, hybrid-electric, and full-electric power systems for this application. The original contributions to the scientific literature on UAM are the detailed modeling approach, the evaluation of CO2 emissions with a Well-to-Wing approach as a function of the electricity Emission Intensity factor, and the comparison with road vehicles performing the same route in different driving conditions. The comparison demonstrates the advantages of a full electric air-taxi with today’s technology versus a hybrid-electric road taxi, especially in cases involving low emission intensity and unfavorable driving conditions (congested traffic, aggressive driving style, and high circuity factor values). In the case of 2035 technology, the comparison with a referenced fully electric road vehicle is detrimental to the air taxi but the values of Well-to-Wheel/Wing CO2 with the expected Emission Intensity of 90 g/kWe for the European Union are still quite low (67 g/km). The investigation also quantifies the negative effect of battery aging on the consumption of the air taxi and on the number of consecutive flights that can be performed without fully charging the battery.

A new approach to three-phase asynchronous motor model for electric power system analysis

In this paper, a new steady-state model of a three-phase asynchronous motor is proposed to be used in the studies of electrical power systems. The model allows for obtaining the response of the demand for active and reactive power as a function of voltage and frequency. The contribution of the model is the integration of the characteristics of the mechanical load that can drive motors, either constant or variable load. The model was evaluated on a 2500 kW and 6000 V motor, for the two types of mechanical load, in a wide range of voltage and frequency, as well as four load factors. As a result of the evaluation, it was possible to verify that, for the nominal frequency and voltage variation, the type of load does not influence the behavior of the powers and that the reactive power is very sensitive to the voltage variation. In the nominal voltage and frequency deviation scenario, it was found that the type of load influences the behavior of the active and reactive power, especially in the variable load. The results demonstrate the importance of considering the model proposed in the simulation software of electrical power systems.

A hybrid algorithm for load curve filtering and clustering

ABSTRACT Clustering of electrical load curves is an important resource used in the analysis of Electric Power Systems, as it extracts characteristics from the behavior of the load. Real data of load curve presents outliers and acquisition problems that are not suitable for clustering. This research proposes a hybrid algorithm for load curve filtering and clustering. An iterative process using the Hampel filter and the Wavelet Transform was applied to filter the data from the load curve. Then, the dimensionality of the load curves was reduced, using the Wavelet Transform, followed by clustering performed with the k-means algorithm. The result of the filtering step demonstrated the effectiveness in correcting abnormalities present in the load curves, thus excluding the load curves with a predominance of abnormalities indicating failures in the measurement system. The clusters resulting from the dimensionality reduction method followed by clustering, originated load curves with well-defined typologies, as well as typical days and periods of the year, in addition to a reduced processing time. The entire methodology was applied using real data from a total of 2588 load curves discretized every 5 minutes.

Developing an electrical power system of a mobile electron beam accelerator to treat wastewater and industrial effluents / Desenvolvimento de um sistema de energia elétrica de um acelerador móvel de feixe de elétrons para tratar águas residuais e efluentes industriais

The treatment of wastewater and industrial effluents by electron beam irradiation is a promising technique, however, not very widespread in Brazilian territory. The design and construction of a mobile unit by the Nuclear and Energy Research Institute, containing an electron beam accelerator of 700 keV and 20 kW is innovative to demonstrate the effects and positive results of this technology. The aim is to transfer the mobile unit to several companies with interest in liquid waste treatment, connect to the industry electrical system and start the ionization treatment process through electron beam. The mobile unit connection to the local electrical system may be a challenge due to the great diversity of voltages and distances involved, as well as the large injections of harmonic content generated by the electron beam accelerator that can affect sensitive loads in the industrial system. In this work, an analysis of the electrical power system of the mobile unit was made, regarding the interruption capacity, selectivity protection and adequate short circuit levels, in order to assure a greater reliability in the operation. At the end, the control panel of the mobile unit, simulations and measurements were carried out at the 1.5 MeV and 37.5 kW electron beam accelerator, installed in the Radiation Technology Center, demonstrating the necessity of applying a filter to reduce the measured harmonic distortion. The analysis of the mobile unit electrical power system was made, in order to assure a greater reliability in the operation.

Probabilistic Assessment of Power Systems with Renewable Energy Sources based on an Improved Analytical Approach

The increasing penetration of renewable energy sources has introduced great uncertainties and challenges into computation and analysis of electric power systems. To deal with uncertainties, probabilistic approaches need to be used. In this paper, we propose a new framework for probabilistic assessment of power systems taking into account uncertainties from input random variables such as load demands and renewable energy sources. It is based on the cumulant-based Probabilistic Power Flow (PPF) in combination with an improved clustering technique. The improved clustering technique is also developed in this study by making use of Principal Component Analysis (PCA) and Particle Swarm Optimization (PSO) to reduce the range of variation in the input data, thus increasing the accuracy of the traditional cumulant-based PPF (TCPPF) method. In addition, thanks to adopting PCA for dimensionality reduction, the improved clustering technique can be effectively dealt with a large number of input random variables so that the proposed framework for probabilistic assessment can be applied for large power systems. The IEEE-118 bus test system is modified by adding five wind and eight solar photovoltaic power plants to examine the proposed method. Uncertainties from input random variables are represented by appropriate probabilistic models. Extensive testing on the test system indicates good performance of the proposed approach in comparison to the traditional cumulant-based PPF and Monte Carlo simulation. The IEEE-118 bus test system is modified by adding five wind and eight solar photovoltaic power plants to examine the proposed method. Extensive testing on the test system, using Matlab (R2015a) on an Intel Core i5 CPU 2.53 GHz/4.00 GB RAM PC, indicates good performance of the proposed approach (PPPF) in comparison to the TCPPF and Monte Carlo simulation (MCS): In terms of computation time, PPPF needs 4.54 seconds, while TCPPF and MCS require 2.63 and 251 seconds, respectively; ARMS errors are calculated for methods using benchmark MCS and their values clearly demonstrate the higher accuracy of PPPF in estimating probability distributions compared to TCPPF, i.e., the maximum (Max) and mean (Mean) values of ARMS errors of all output random variables are: ARMSPPPFmax = 0.11%, ARMSTCPPFmax = 0.55%, and ARMSPPPFmean = 0.06%, ARMSTCPPFmean = 0.35%.

Grid Resilience analysis and planning of electric power systems: The case of the 2021 Texas electricity crises caused by winter storm Uri (#TexasFreeze)

The frequency of Very Large-Scale Weather Events (VLSWEs) such as Superstorm Sandy in 2012, Hurricane Maria in 2017 and Winter Storm Uri in 2021, among others, in the last decade have led increased conversations around the topic of grid resilience, by grid operators, planners, government agencies and other industry stakeholders. These events, which were to only occur “once in 100 years” exert a heavy toll on life and property. For example, winter storm Uri and the statewide power outages it caused in Texas directly and indirectly led to the death of 210 people and by some estimates caused over $120 billion in economic losses. The 2021 Texas electricity crises, which led to over 4 million people losing electricity and water for almost a week has brought about a renewed interest in the resilience of the electric power system in general and the Electric Reliability Council of Texas (ERCOT) in particular. Historically these conversations have been about grid reliability, but with the increase in frequency and the sheer size of devastation caused by VLSWEs more holistic and robust approaches to addressing their effects on the grid are being considered by industry stakeholders and policy makers. In this paper the events of this crisis are analyzed using a syncretistic approach developed from analyzing and then synthesizing important resilience constructs, frameworks and concepts.