Electric Power System Analysis Research Articles

Demand Side Management Techniques for Home Energy Management Systems for Smart Cities

In this paper, three distinct distributed energy resources (DERs) modules have been built based on demand side management (DSM), and their use in power management of dwelling in future smart cities has been investigated. The investigated modules for DERs system are: incorporation of load shedding, reduction of grid penetration with renewable energy systems (RES), and implementation of home energy management systems (HEMS). The suggested approaches offer new potential for improving demand side efficiency and helping to minimize energy demand during peak hours. The main aim of this work was to investigate and explore how a specific DSM strategy for DER may assist in reducing energy usage while increasing efficiency by utilizing new developing technology. The Electrical Power System Analysis (ETAP) software was used to model and assess the integration of distributed generation, such as RES, in order to use local power storage. An energy management system has been used to evaluate a PV system with an individual household load, which proved beneficial when evaluating its potential to generate about 20–25% of the total domestic load. In this study, we have investigated how smart home appliances’ energy consumption may be minimized and explained why a management system is required to optimally utilize a PV system. Furthermore, the effect of integration of wind turbines to power networks to reduce the load on the main power grid has also been studied. The study revealed that smart grids improve energy efficiency, security, and management whilst creating environmental awareness for consumers with regards to power usage.

Analysis of Electric Power Systems with Untransposed Transmission Lines.(Dept.E)

Untransposition in O.H.T.L. creates the unequiality of T.L. phase impedances. Several problems are srised due to the out -of- balance of the phase impedances. The main of which is that it affects on the system performance. For the seek of system analysis with untransposed T.L., the modeling of system element in matrix form is given and the modeling of the power system as a whole is also cleared. The methods for the reduction of the out-of-balance are discussed and the flow-chart for the problem analysis is given. It could be noticed that transposition is the best method for the out-of-balance reduction, but it reduces the reliability of the system.

A Case Study of an Industrial Power Plant under Cyberattack: Simulation and Analysis

For critical infrastructures, technological developments regarding real-time data transmission and processing improve the system’s operability and reliability. However, vulnerabilities are introduced in the case of implementing new remote access methods or where redundancy is low. At the national level, most critical infrastructures are connected, and, therefore, achieving a level of security and resilience is based on identifying a multitude of risks. In this respect, the reduction of risk to acceptable levels directly affects the quality of citizens’ lives and decreases losses in the industry. This study starts from the threats to power systems, namely cyberattacks, which are much more dangerous, although less visible, to operators, and almost invisible to the public or the media. From this point of view, it was proved that the most vulnerable parts of the power system were human–machine interfaces, electrical equipment, Surveillance, Control, and Data Acquisition (SCADA) systems. This paper’s main achievements include the simulation of cyberattacks on existing electrical equipment from a petrochemical plant (case study), which consists of modifying the remote data transmitted by the SCADA system. Two locations were submitted to simulated cyberattacks that were considered critical for the overall plant operation. Furthermore, the changes that occur following each fault resulting from the cyberattack and the influence of the electrical parameter changes upon the process flow were analyzed. Furthermore, by using Electrical Power System Analysis Software—ETAP—the changes that occur following each fault due to the cyberattack and the influence of the electrical parameter changes upon the process flow were analyzed. By considering the two malfunction events, the resilience assessment of the system was analyzed. In the second case, only partial resilience action, up to 40%, restored the operability of the industrial power plant.

Sensitivity factors in electricity-heating integrated energy systems

In integrated energy systems, adjusting the energy conversion of a coupling unit changes the power flow in the connected energy systems. Also, it forces other units to adapt their generation to keep the energy balance in the energy systems. The impact on the power flow and the complexity of the interaction between single networks will increase the more coupling units are installed. The impact on the power flow can be determined by power flow calculation and optimization algorithms. However, to analyze the impact of a unit’s power change on all state variables, the available methods need to solve a second power flow or optimization. This is computationally effortful and time-consuming. Hence, this paper proposes a method that estimates such a change easily and quickly. The method extends the widely used approach of sensitivity factors in electric power system analysis to electricity-heating integrated energy systems. The sensitivity factors are derived in a straightforward way by linearization using the Jacobian matrix of a coupled power flow calculation before the change. These new sensitivity factors can precisely estimate the impact of a change on the energy system’s power flow and reduce the calculation time of new setpoints by factor eight on average.

Simulink Matlab applications program in power system: Study of effect of simulink matlab program acceptance in power system analysis

The Simulink Matlab application program in electrical power system analysis needs acceptance from its users. This research is purposed to investigate the effect of Simulink Matlab application program acceptance to power system analysis. This research uses a quantified approach. The sample of this research is 119 students using the Simulink Matlab application program to do power system analysis. The data is analyzed with path analysis with the Partial Least Square approach. The result shows that the perception of ease has a direct effect to the perception of usage, behavior, and intention to use the Simulink application program with the path coefficient of 0.581, 0.574, and 0.249 respectively; the perception of usage and easiness in the usage of the Simulink application program has a direct effect to behavior in using the Simulink application program with the path coefficient of 0.218 and 0.574 respectively; the behavior in using the Simulink application program has a direct effect to the intention in using the Simulink application program with the path coefficient of 0.581, and the intention in using Simulink application program has a direct effect to the usage of the real Simulink Matlab application program with the path coefficient of 0.491. This research concludes that the usage of the Simulink application program for power system analysis is affected by the easiness and the usage of the application as well as the attitude of users.

New Iterative Method Based Jacobian Matrix and λ<sub>opt</sub> to Solve Power Flow Equation for Islanded MGs

Power flow analysis and calculation play an essential role in analysis of electrical power system. Solving the load flow equations of an electrical power system are very sensitive to the value of the right-hand side constant vector or to the value of the coefficients of the Jacobian matrix, the equations of the electrical power system are called to be ill-conditioned. In an ill-conditioned case study, the determinant of the Jacobian matrix is close to singular or singular. Computing the set of load flow equations of an electrical power system may sometimes lead to the incidence of the ill-conditioned equations. The ill-conditioning mood in MGs power system is due to several reasons such as the situation of the reference bus, high value of r/x ratio of power system's lines, connections of very low and very high impedance power system's lines at a bus and heavy loading condition of an electrical power system. In an islanded MG, the use of traditional PFA is not effective as the voltage of the swing or slack bus and the frequency of the MG are assumed to be constant. This paper proposes a simple and effective iterative method based on the Jacobian matrix λ_opt to solve the PF equation for islanded MGs. The new proposed technique prepares a simple, straightforward for implementation, and precise technique to calculate the PF equations for MGs. The new suggested technique is exerted to the 38-bus case study electrical power system. The outcomes are compared against simulation outcomes that accredit the efficiency of the new technique.

A Hetero-Functional Graph Resilience Analysis of the Future American Electric Power System

As climate change takes hold in the $21^{st}$ century, it places an impetus to decarbonize the American Electric Power System with renewable energy resources. There is a broad technical consensus that these renewable energy resources cannot be integrated alone but rather require a host of profound changes in the electric grid’s architecture; including meshed distribution lines, and energy storage solutions. One question that arises is whether these three types of mitigation measures required by decarbonization will also serve as adaptation measures when the climate changes and extreme weather phenomena become more prevalent. Consequently, this paper presents a structural resilience analysis of the American electric power system that incrementally incorporates these architectural changes in the future. Building upon a preliminary study, the analysis draws on an emerging hetero-functional graph theory based upon the inter-connectedness of a system’s capabilities. The hetero-functional graph analysis confirms our formal graph understandings from network science in terms of cumulative degree distributions and traditional attack vulnerability measures. The paper goes on to show that hetero-functional graphs relative to formal graphs more precisely describe the changes in functionality associated with the addition of distributed generation and energy storage as the grid evolves to a decarbonized architecture. Finally, it demonstrates that the addition of all three types of mitigation measures enhance the grid’s structural resilience; even in the presence of disruptive random and targeted attacks. The paper concludes that there is no structural trade-off between grid sustainability and resilience enhancements and that these strategic goals can be pursued simultaneously.

Integrasi Model Pembangkit Listrik Tenaga Angin Pada Analisis Aliran Daya Sistem Tenaga

This paper proposes a new method for modeling and integrating wind turbine generating system (WTGS) into power flow analysis. The proposed WTGS model is based on the slip calculation of the WTGS induction generator. Unlike some previous methods where machine slip is determined after the iteration process has been completed, in the proposed method, machine slip is included in the calculation or iteration process and computed together with other electrical quantities. In this way, the formulation for induction generator rotor voltage (which is usually complicated and often represented by bi-quadratic equation) is no longer needed in the modeling. Validation results show that the proposed method is accurate. The application of the WTGS model in load flow analysis of the multi-bus electric power system is also presented. In addition, the effect of WTGS installation on system steady-state performance is also investigated in this paper.

Power System Analysis Using LabVIEW

The focus of this work is on investigation of LabVIEW electric power tool in particular and LabVIEW software in general for the analysis and design of electric power systems. Here we are targeting the solution of different electrical engineering problems which we very often face in teaching the course of power system analysis. At the time being, at Zarqa University, we are preparing a self study report for submission to ABET for accreditation of electrical engineering program. ABET considers that the application of different software tools during the learning process is essential and must be covered. Thus, power system analysis course has been selected as one of the courses that are decided to reach this outcome. As a result of that, a literature survey was conducted and several relevant topics were selected to be investigated. This included the following: simulation of on-line measurement of RMS and instantaneous values of electric power, calculation of symmetrical components using matrix analysis, on-line estimation of symmetrical components, use of phasor analysis to find phasor magnitude and phase angles, conversion of star to delta and delta to star configurations, and simulation of rotating phasors. All designed virtual instruments were analyzed, tested, and chosen solved examples gave very accurate results.

An approach for contingency ranking analysis of electrical power system

This paper presents an algorithm for ranking the critical contingencies in a high voltage power system. The presented approach based on a hybrid weighted performance index. The hybrid performance index measures the overloaded transmission lines and bus voltage deviation out the permissible limits. A linear technique is used in computing the hybrid performance index. The proposed algorithm is applied to the IEEE24 bus reliability test system. There is a good match between the results obtained with the proposed algorithm with those obtained by applying a full AC load flow iterative method.

Comparison of Numerical Methods and Open-Source Libraries for Eigenvalue Analysis of Large-Scale Power Systems

This paper discusses the numerical solution of the generalized non-Hermitian eigenvalue problem. It provides a comprehensive comparison of existing algorithms, as well as of available free and open-source software tools, which are suitable for the solution of the eigenvalue problems that arise in the stability analysis of electric power systems. The paper focuses, in particular, on methods and software libraries that are able to handle the large-scale, non-symmetric matrices that arise in power system eigenvalue problems. These kinds of eigenvalue problems are particularly difficult for most numerical methods to handle. Thus, a review and fair comparison of existing algorithms and software tools is a valuable contribution for researchers and practitioners that are interested in power system dynamic analysis. The scalability and performance of the algorithms and libraries are duly discussed through case studies based on real-world electrical power networks. These are a model of the All-Island Irish Transmission System with 8640 variables; and, a model of the European Network of Transmission System Operators for Electricity, with 146,164 variables.

Comparison of Industrial Substation Arrangements

This paper presents a comparative analysis for two alternatives of industrial substation arrangement with selective secondary radial type: first with one main transformer and one reserve and the second one with two main transformers and one reserve. The analysis are based on the power flow calculation, short circuit and reliability indices using the Electrical Power System Analysis Software (ETAP) and on the acquisition costs of equipment and materials. The analysis' methodology application in both alternatives is presented and the results are analyzed and compared as well.

Stochastic Eigen-Analysis of Electric Power System With High Renewable Penetration: Impact of Changing Inertia on Oscillatory Modes

This article proposes a framework for stochastic eigenvalue analysis of electric power systems with a high penetration of inertialess renewable generation, focusing on the influential factors that affect the eigenvalue movement resulting from the inertia reduction. We analytically investigate the influence of the inertia and the variation in renewable generation on small-signal stability using stochastic Monte-Carlo based eigenvalue and modal controllability analysis. With the increasing penetration of renewable generation, power system behavior depends on meteorological conditions more, which results in the reduction of power system inertia due to the decommitment of generators and a consequent deterioration of power system stability. Against this backdrop, stochastic eigenvalue analysis is carried out to examine the movement of eigenvalues resulting from the variable operating conditions. The contribution of the generators to the oscillatory modes is theoretically proved using modal controllability in a power system with reduced inertia. For the verification of the research, the simulation is carried out using DIgSILENT/PowerFactory.

Fault Analysis of Electric Power System using PLC and Wireless Communication System

In present scenario electricity theft is the major hurdle in front of government. This paper comprises of functions and architecture of the smart metering and monitoring network system which works on real time data communication and have its own network. Our main motive is to design and develop such a wireless metering system which will prevent power theft and provide us a reliable and accurate metering monitoring system by using modern technology. The design comprises of wireless power metering and monitoring network which will work on principle of real time data communication(which is not available in existing wireless GSM metering system) and will use its own reliable network with the help of Programmable Logic Controller. Programmable Logic Controller, smart meters, wireless communication modules and profinet cable are the key components of the system. To provide a better and easy human interface with the smart meter we are using simplify S CADA and programming which is very user affable.

Modeling of multi-physics transients in PEM fuel cells using equivalent circuits for consistent representation of electric, pneumatic, and thermal quantities

Digital simulators of electric networks have been indispensable tools for engineers and researchers engaged in the analysis and design of electric power and energy systems. With the increasing interest to extend electric energy toward multi-energy systems covering multiple energy carriers, there arises a need to also extend the capabilities of today’s simulators. Such an extension is proposed here in the form of a Proton Exchange Membrane Fuel Cell (PEMFC) model that covers the multi-physics transients involved in the flows of the electric current, hydrogen and other gases, and the enthalpy. The modeling makes use of given analogies to allow for a uniform representation of electric, pneumatic, and thermal transients based on electric circuit equivalents. It is shown how these models representing different transients are coupled as part of a PEM fuel cell system. Validation and application are carried out to verify the value of the modeling. The investigations are performed with an electric network simulator of type EMTP (Electromagnetic Transients Program) and so substantiate the possibility of using the latter for studying multi-energy systems.

Reliability analysis for electric power systems of more-electric aircraft based on the minimal path set

With the raise of aircraft performance and the increasing electrical applications, the more-electrical or all-electric aircraft will become the main aircraft model in future. The reliability assessment of aircraft electric power system is critical to guarantee the reliable operation of the aircraft . A reliability assessment method for complex power system of large aircraft such as Boeing 787 has been described in this paper. First the aircraft power distribution system is abstracted as a topology diagram based on the graph theory. Then the minimal path sets are searching from the source node to the load nodes by the depth-first search. These path sets can represent the normal power supply path of the electric power system. Finally, using the raw reliability data of components, the reliability function of various important buses is established and the reliability index of large aircraft power distribution system is calculated. This assessment method can be used to analyze and assess the reliability of power supply and distribution system of different models and to provide a reference for the design and analysis of complex electric power system of civil aircraft.

Field validation of a standard Type 3 wind turbine model implemented in DIgSILENT-PowerFactory following IEC 61400-27-1 guidelines

Transient stability analyses are one of the key tools used to ensure grid stability and safeguard security of electricity supply, as well as to comply with different countries grid interconnection agreements. Transmission and distribution system operators require validated wind turbine models to perform these studies. This is becoming increasingly important in current power systems because wind energy penetration is constantly expanding, and its integration has a significant impact on power grid planning and operation. The definition of generic wind turbine models by international standard IEC 61400-27-1, first released in February 2015, aims to deal with this issue. Therefore, since the validation process of the most widely used model defined by this standard and one of the most technically advanced, the generic type 3 wind turbine, i.e., the doubly-fed induction generator, has only been conducted using non-specialised software tools in the field of electrical engineering, the present paper addresses the validation process of this WT when simulated in one of the leading electric power system analysis software tools: DIgSILENT-PowerFactory. The model is subjected to voltage dips of varying magnitude and duration, under both full and partial load conditions. The results are compared to field measurement data according to IEC 61400-27-1 guidelines, and validation errors are estimated.

Toward a More Reliable System for Contingency Selection in Static Security Analysis of Electric Power Systems

The reliable supply of electricity plays a key role in the contemporary way of life. In order to provide more benefits to the population, electric networks are getting bigger to produce more energy. This growth, while necessary, brings problems in operation and maintenance, since the networks are more complex. This complexity requires that network security analysis should be performed in real time to avoid decision errors when disconnecting a device from the network or predicting the possibility of operating output from an undersized device. In this article, an intelligent system for contingency selection in the static security analysis of electric power systems is proposed. The severity of contingencies indication is the first step to develop control actions and maintain the system operation integrity. We propose and evaluate the contingency selection as a combinatorial optimization problem, employing an ACO metaheuristic to model the situation. The system is evaluated over the IEEE 30-bus network and a real 810-bus network, considering double outages of branches. Results show an accuracy close to five-nines for severing contingencies.

A New Approach for Contingency Analysis Based on Centrality Measures

The contingency analysis of power systems represents a critical part of security monitoring, required to maintain power system reliability. In general, traditional $N-1$ contingency analysis methods simulate a few outages, due to the high computational costs involved. Thus, they may fail to identify some critical contingencies that can lead to cascading failures. This paper proposes a new approach to $N-1$ contingency analysis of electric transmission systems, based on network centrality measures. The proposed method evaluates all possible transmission line outages in a very short computational time, and it requires only topological information. Results are shown for two electric power systems: ITAIPU 11 bus and IEEE 39 bus. Comparisons between the results obtained by the proposed method and traditional ones show the accuracy of the proposed method to identify critical buses and transmission lines, in local and global context, even in absence of electrical information. The proposed method is interesting as a direct and fast tool applied to the pre-analysis process, since topological network behavior is verified. Thus, pre-analysis provides a prior response to the system operator of the points by which the electrical power system analysis should begin, in order to ensure safe operational state of the system.

Simulink-based programs for power system dynamic analysis

This paper introduces Simulink-based programs developed for dynamic analysis of electrical power systems. The program can be used for research studies or as a teaching tool. With the program, time-domain simulation, modal analysis, participation factor analysis and visualization, frequency response analysis, and design of conventional and intelligent controllers can be obtained. A special case of constant impedance load is also studied. IEEE 9-bus, IEEE 68-bus, Texas 2007-bus 282-machine, and the 25,000-bus northeastern US test systems are employed in this paper. The synchronous machines are assumed to be equipped with exciter, turbine, and stabilizer. Static var compensator is added using conventional and adaptive neuro-fuzzy controllers. Different types of disturbances are applied to the systems including generator-side and network-side disturbances. The program is free of algebraic loops that may increase the errors and slow down the simulation. All blocks and signals in the Simulink model are in vector form that can be used to simulate a power system of any size.