scholarly journals Power system voltage collapse prediction using a new line stability index (NLSI-1): A case study of the 330-kV nigerian national grid

2019 ◽  
Vol 9 (6) ◽  
pp. 5125
Author(s):  
I. A. Samuel ◽  
J. Katende ◽  
C. O. A. Awosope ◽  
A. A. Awelewa ◽  
A. I. Adekitan ◽  
...  
Keyword(s):  
Power System ◽  
Stability Index ◽  
Base Case ◽  
Voltage Collapse ◽  
Cumulative Number ◽  
The Novel ◽  
A Value ◽  
System Collapse ◽  
The Difference ◽  
Reliability Issue

The cumulative number of historical and recent power system outages substantiates the fact that further studies are necessary for an improved solution to the issue of voltage instability on the grid and the subsequent system collapse. Voltage collapse is a serious reliability issue which inhibits the objective of running a reliable and secure power system network. In this study, a new line stability index (NLSI_1) for predicting voltage collapse is presented.  The new index considers a switching logic which is derived from the difference of voltage angle between the two load buses. The index is deployed for performance analysis using the 28-bus, 330-kV Nigeria National Grid (NNG).  The simulation implemented in MATLAB shows that the index gives the same results as Line stability index (Lmn) and Fast Voltage Stability Index (FVSI) indices. The base case and the contingency scenarios were considered during the simulation. The base case analysis using the NNG values of all the three indices FVSI, Lmn, and NLSI_1 for simulation generates a value less than one for the entire lines which implies that the NNG is stable in this mode. The values of the three indices are almost the same, which confirms the accuracy of the novel index developed. The analysis for the contingency case reveals that the load bus 16 (Gombe) which has the lowest, maximum permissible reactive load of 139.5MVAR is the weakest; also power line 16-19 is identified as the critical line. The result of the simulation confirms that the accuracy was improved by using NLSI_1.

scholarly journals Voltage Collapse Prediction of IEEE 30-Bus system

2021 ◽  
Vol 28 (1) ◽  
pp. 98-112
Author(s):  
Mohammed Ibrahim ◽  
Abdulsattar Jasim
Keyword(s):  
Power System ◽  
Modal Analysis ◽  
Voltage Stability ◽  
Stability Index ◽  
Maximum Load ◽  
Voltage Collapse ◽  
Analysis Method ◽  
The Stability ◽  
Stability Indices ◽  
Participation Factor

Voltage collapse in the power system occurs as a result of voltage instability, thus which lead to a blackout, and this is a constant concern for network workers and customers alike. In this paper, voltage collapse is studied using two approved methods: the modal analysis method and voltage stability indices. In the modal analysis method, the eigenvalues were calculated for all the load buses, through which it is possible to know the stability of the power system, The participation factor was also calculated for the load buses, which enables us to know the weakest buses in the system. As for the Voltage stability Indices method, two important indices were calculated, which are: Fast Voltage Stability Index (FVSI) and Line stability index (Lmn). These two indices give a good visualization of the stability of the system and the knowledge of the weakest buses, as well as the Maximum load-ability of the load buses. The above mentioned two methods were applied using software code using MATLAB \ R2018a program to the IEEE 30-Bus test system. In the modal analysis, the buses which have the maximum participation factor are 26, 29, and 30 this indicates that they are the weakest in the system. as well as in the voltage stability indices. These buses have the lowest maximum load ability which demonstrates the possibility of using both methods or one of them to study the voltage collapse.

scholarly journals New Techniques for the Prevention of Power System Collapse

2013 ◽  
pp. 294-300
Author(s):  
Fouzul Azim Shaikh ◽  
Ramanshu Jain ◽  
Mukesh Kotnala ◽  
Nickey Agarwal
Keyword(s):  
Power Systems ◽  
Power System ◽  
Distribution System ◽  
Reactive Power ◽  
Low Voltage ◽  
Point Of View ◽  
Voltage Collapse ◽  
Transmission Grid ◽  
System Collapse ◽  
Stability Point

From voltage stability point of view, maximum permissible loading limits must not be exceeded in the operation of power systems. The risk of cascading outages in power systems manifests itself in a number of ways like loss of generation units, breaker failures, common tower and common right-of-way circuit outages, combination of system conditions and events. With the advent of structured competitive power markets, and with the lack of needed investment in the transmission grid, electric power systems are increasingly being operated close to their limits. When a power system is subjected to large disturbances control actions need to be taken to steer the system away from severe consequences and to limit the extent of the disturbance. The main factor, which causes these unacceptable voltage transients, is the inability of the distribution system to meet the demand for reactive power. The major research in dealing with voltage collapse is the proper diagnosis of the underlying factors causing low voltage. These disturbances often result in voltage collapse of the system, which in turn causes huge losses in the system as well as monetary losses. This paper deals with some newer techniques for the prevention of the voltage system collapse for voltage system collapse, which may have a very large economic impact on the society. It also focuses on right initiation at right time to ease control action to enhance stability, reliability and security of the power system so as to provide a preventive plan to minimize the chances of failure in power system as possible.

scholarly journals Novel Voltage Stability Index for Electric Power System Monitoring

2019 ◽  
Vol 10 (1) ◽  
pp. 1-9
Author(s):  
Aziz Oukennou ◽  
Abdelhalim Sandali
Keyword(s):  
Power System ◽  
Power Flow ◽  
Voltage Stability ◽  
Stability Index ◽  
Test System ◽  
Electric Power System ◽  
Monitoring Tool ◽  
Voltage Stability Index ◽  
Power System Monitoring ◽  
The Difference

This paper aims to develop a novel voltage stability index (NVSI) to evaluate and detect the voltage collapse proximity in the power system. This NVSI is based on the combination of two indices and the approximation made on the difference in angle between the sending bus and the receiving one in the power system. Compared to indices developed in the literature, the advantage of the new voltage stability index (NVSI) is that it can be computed very quickly and easily from power flow results, such as voltages, magnitudes and angles. The static and dynamic studies have been carried out on the IEEE 14-bus test system using PSAT Software. The proposed index has shown more sensitivity and simplicity, and that it can be used as a monitoring tool.

scholarly journals Voltage Stability Index Calculation by Hybrid State Estimation based on Multi Objective Optimal Phasor Measurement Unit Placement

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2688
Author(s):  
Matsukawa ◽  
Watanabe ◽  
Wahab ◽  
Othman
Keyword(s):  
Power System ◽  
State Estimation ◽  
Voltage Stability ◽  
Stability Index ◽  
Phasor Measurement Unit ◽  
Measurement Unit ◽  
Voltage Collapse ◽  
Hybrid State ◽  
Voltage Stability Index ◽  
Critical Boundary

Operation of a power system close to the voltage stability limit due to increasing of load demand and limited power sources may result in disastrous economic loss with voltage collapse of the entire power system. A system operator has to understand how far the system is from the critical boundary of the voltage collapse. This paper investigated the influence of State Estimation (SE) in the calculation of the Critical Boundary Index (CBI) as a voltage stability index. For SE, Hybrid State Estimation (HSE), including the measurement set of both Remote Terminal Unit (RTU) in Supervisory Control and Data Acquisition (SCADA) and Phasor Measurement Unit (PMU), is employed. Concurrently, the CBI is estimated using voltage phasor estimated by HSE based on optimal PMU location, which is selected from a Pareto optimal front obtained by the Non-dominated Sorting Genetic Algorithm II (NSGA-II). As a result of CBI estimation, HSE using PMU is relatively accurate in voltage stability index estimation compared to SCADA SE, which uses the RTU alone. However, when a mixed measurement condition in some lines affects the CBI estimation, it is suggested that it may be necessary to discard PMU measurements in some cases.

PENGAKUAN CALABAI: SEBUAH ANALISIS INTERTEKSTUAL NOVEL PASUNG JIWA KARYA OKKY MADASARI DAN NOVEL CALABAI KARYA PEPI AL-BAYQUNIE

Jurnal KATA ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 50
Author(s):  
Krisna Aji Kusuma ◽  
Herman J Waluyo ◽  
Nugraheni Eko Wardani
Keyword(s):  
Content Analysis ◽  
Analysis Data ◽  
Qualitative Approach ◽  
The Novel ◽  
Research Results ◽  
Self Actualization ◽  
Similarities And Differences ◽  
The Difference ◽  
Descriptive Qualitative

<p><em>This study aims to describe the intertextuality relationship between the novel Pasung Jiwa by Okky Madasari and Calabai by Pepi Al-Bayqunie. The type of research is descriptive qualitative approach using content analysis. Data are collected by inventorying events that are similarities and differences, specifications on the characters, settings, plots, and themes of both text. The research results indicate that there are similar themes on the two novels, the theme of self actualization in addition with the theme of family and friendship. The same characterization are also used by both author, masculine figures with feminine soul characters. The difference between the two novels lies on the plot and setting. Pasung Jiwa uses progressive plot and Calabai uses a flash-back plot.. Okky Madasari takes Java Island as the background in the novel Pasung Jiwa, while the novel Calabai, Pepi Al-Bayqunie using the setting of Sulawesi Island. The basis of the similarity of theme and characterization supported by the similirity of events in the story shows the existence of intertextual relationship between the two novels. As a previously published work, the novel Pasung Jiwa by Okky Madasari is a hipogram and novel Calabai by Pepi A-Bayqunie as a transformational text. On the theme and characterization, the transformation of Calabai forward the hypogram, while in the plot and setting deviates his hypogram, Pasung Jiwa.</em></p><p>Penelitian ini bertujuan untuk mendeskripsikan hubungan intertekstualitas antara novel Pasung Jiwa karya Okky Madasari dan novel Calabai karya Pepi Al-Bayqunie. Jenis penelitian ini adalah deskriptif kualitatif dengan pendekatan konten analisis. Data dikumpulkan dengan menginventariskan peristiwa yang merupakan persamaan dan perbedaan, spesifikasi pada tokoh, latar, alur, dan tema dari kedua teks. Hasil penelitian ini menunjukkan bahwa terdapat kesamaan tema pada kedua novel, yaitu tema aktualisasi diri, ditambah dengan tema keluarga dan persahabatan. Penokohan yang sama juga digunakan oleh kedua penulis, yaitu tokoh maskulin dengan karakter jiwa feminin. Perbedaan kedua novel terletak pada alur dan latar. Pasung Jiwa menggunakan alur maju dan Calabai menggunakan alur campuran. Latar dalam novel Pasung Jiwa, Okky Madasari mengambil latar Pulau Jawa, sedangkan novel Calabai, Pepi Al-Bayqunie menggunakan latar Pulau Sulawesi. Dasar kesamaan tema dan penokohan didukung kesamaan peristiwa-peristiwa dalam cerita menunjukkan adanya hubungan intertekstual antara kedua novel. Sebagai karya yang terbit terlebih dahulu menjadikan novel Pasung Jiwa karya Okky Madasari adalah hipogram dan novel Calabai karya Pepi Al-Bayqunie sebagai teks transformasi. Pada tema dan penokohan, transformasi Calabai meneruskan hipogram, sedangkan pada alur dan latar menyimpangi hipogramnya, Pasung Jiwa.</p>

scholarly journals Modelling spreading of an infection using time series by a novel family of models; fitting the time series of the confirmed cases of COVID-19 in China

2020 ◽  
Vol 9 (s1) ◽  
Author(s):  
Babak Jamshidi ◽  
Shahriar Jamshidi Zargaran ◽  
Mansour Rezaei
Keyword(s):  
Infectious Disease ◽  
Time Series ◽  
Communicable Disease ◽  
Time Series Models ◽  
Cumulative Number ◽  
The Novel ◽  
New Family ◽  
Two Samples ◽  
Almost All ◽  
Number Of Individuals

AbstractIntroductionTime series models are one of the frequently used methods to describe the pattern of spreading an epidemic.MethodsWe presented a new family of time series models able to represent the cumulative number of individuals that contracted an infectious disease from the start to the end of the first wave of spreading. This family is flexible enough to model the propagation of almost all infectious diseases. After a general discussion on competent time series to model the outbreak of a communicable disease, we introduced the new family through one of its examples.ResultsWe estimated the parameters of two samples of the novel family to model the spreading of COVID-19 in China.DiscussionOur model does not work well when the decreasing trend of the rate of growth is absent because it is the main presumption of the model. In addition, since the information on the initial days is of the utmost importance for this model, one of the challenges about this model is modifying it to get qualified to model datasets that lack the information on the first days.

scholarly journals The Water Footprint of Primary and Secondary Processing of Beef from Different Cattle Breeds: A Value Fraction Allocation Model

2021 ◽  
Vol 13 (12) ◽  
pp. 6914
Author(s):  
Frikkie Alberts Maré ◽  
Henry Jordaan
Keyword(s):  
Water Footprint ◽  
Negative Relationship ◽  
High Water ◽  
Allocation Model ◽  
Cattle Breeds ◽  
A Value ◽  
Average Production ◽  
High Water Intake ◽  
The Difference ◽  
By Products

The high water intake and wastewater discharge of slaughterhouses have been a concern for many years. One neglected factor in previous research is allocating the water footprint (WF) to beef production’s different products and by-products. The objective of this article was to estimate the WF of different cattle breeds at a slaughterhouse and cutting plant and allocate it according to the different cuts (products) and by-products of beef based on the value fraction of each. The results indicated a negative relationship between the carcass weight and the processing WF when the different breeds were compared. Regarding a specific cut of beef, a kilogram of rib eye from the heaviest breed had a processing WF of 614.57 L/kg, compared to the 919.91 L/kg for the rib eye of the lightest breed. A comparison of the different cuts indicated that high-value cuts had higher WFs than low-value cuts. The difference between a kilogram of rib eye and flank was 426.26 L/kg for the heaviest breed and 637.86 L/kg for the lightest breed. An option to reduce the processing WF of beef is to lessen the WF by slaughtering heavier animals. This will require no extra investment from the slaughterhouse. At the same time, the returns should increase as the average production inputs per kilogram of output (carcass) should reduce, as the slaughterhouse will process more kilograms.

scholarly journals Characterization of the SARS-CoV-2 coronavirus X4-like accessory protein

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Olanrewaju Ayodeji Durojaye ◽  
Nkwachukwu Oziamara Okoro ◽  
Arome Solomon Odiba
Keyword(s):  
Rapid Development ◽  
Protein A ◽  
The Novel ◽  
Quality Model ◽  
A Value ◽  
Model Protein ◽  
Novel Coronavirus ◽  
Global Threat

Abstract Background The novel coronavirus SARS-CoV-2 is currently a global threat to health and economies. Therapeutics and vaccines are in rapid development; however, none of these therapeutics are considered as absolute cure, and the potential to mutate makes it necessary to find therapeutics that target a highly conserved regions of the viral structure. Results In this study, we characterized an essential but poorly understood coronavirus accessory X4 protein, a core and stable component of the SARS-CoV family. Sequence analysis shows a conserved ~ 90% identity between the SARS-CoV-2 and previously characterized X4 protein in the database. QMEAN Z score of the model protein shows a value of around 0.5, within the acceptable range 0–1. A MolProbity score of 2.96 was obtained for the model protein and indicates a good quality model. The model has Ramachandran values of φ = − 57o and ψ = − 47o for α-helices and values of φ = − 130o and ψ = + 140o for twisted sheets. Conclusions The protein data obtained from this study provides robust information for further in vitro and in vivo experiment, targeted at devising therapeutics against the virus. Phylogenetic analysis further supports previous evidence that the SARS-CoV-2 is positioned with the SL-CoVZC45, BtRs-BetaCoV/YN2018B and the RS4231 Bat SARS-like corona viruses.

scholarly journals A Fast Retrieval of Cloud Parameters Using a Triplet of Wavelengths of Oxygen Dimer Band around 477 nm

2021 ◽  
Vol 13 (1) ◽  
pp. 152
Author(s):  
Haklim Choi ◽  
Xiong Liu ◽  
Gonzalo Gonzalez Abad ◽  
Jongjin Seo ◽  
Kwang-Mog Lee ◽  
...  
Keyword(s):  
Scattered Light ◽  
Trace Gas ◽  
Retrieval Algorithm ◽  
The Novel ◽  
Cloud Parameters ◽  
Retrieval Scheme ◽  
The Difference ◽  
The Look ◽  
Time Required ◽  
Cloud Top Pressure

Clouds act as a major reflector that changes the amount of sunlight reflected to space. Change in radiance intensity due to the presence of clouds interrupts the retrieval of trace gas or aerosol properties from satellite data. In this paper, we developed a fast and robust algorithm, named the fast cloud retrieval algorithm, using a triplet of wavelengths (469, 477, and 485 nm) of the O2–O2 absorption band around 477 nm (CLDTO4) to derive the cloud information such as cloud top pressure (CTP) and cloud fraction (CF) for the Geostationary Environment Monitoring Spectrometer (GEMS). The novel algorithm is based on the fact that the difference in the optical path through which light passes with regard to the altitude of clouds causes a change in radiance due to the absorption of O2–O2 at the three selected wavelengths. To reduce the time required for algorithm calculations, the look-up table (LUT) method was applied. The LUT was pre-constructed for various conditions of geometry using Vectorized Linearized Discrete Ordinate Radiative Transfer (VLIDORT) to consider the polarization of the scattered light. The GEMS was launched in February 2020, but the observed data of GEMS have not yet been widely released. To evaluate the performance of the algorithm, the retrieved CTP and CF using observational data from the Global Ozone Monitoring Experiment-2 (GOME-2), which cover the spectral range of GEMS, were compared with the results of the Fast Retrieval Scheme for Clouds from the Oxygen A band (FRESCO) algorithm, which is based on the O2 A-band. There was good agreement between the results, despite small discrepancies for low clouds.

Sign in / Sign up

Export Citation Format

Share Document