scholarly journals EVALUATION OF THE ERROR EFFECT IN SYNCHRONOUS VECTOR MEASUREMENTS OF ANGLES AT VOLTAGES ON ASSESSING THE DUTY PARAMETERS OF ELECTRIC POWER SYSTEMS

Author(s):  
Natalia L. Batseva ◽  
Julia A. Foos ◽  
Aleksey V. Pankratov

Telemeasurements and telesignals coming from telemechanics devices to the operational information complex are used as the initial data for solving the problem of state assessment. The disadvantage of telemeasurement chopping is that they do not contain angles at voltages that are necessary for assessing the mode parameters in solving a number of technological problems. Implementing the Transitional Modes Monitoring System has provided opportunities to improve solving the problem of state assessing by the data of synchronous vector measurements coming from synchronous vector measurement devices. However, failures on the satellite channel of synchronous vector measurement devices, as well as high load of communication networks result in errors in the arrays of synchronous vector measurements. The question of accuracy in solving the problem of state assessing at the influence of errors in synchronous vector measurements of angles at voltages on the mode parameters is not fully studied and is at the stage of research. State assessment is done using algorithms based on mathematical methods. The existing algorithms do not make it possible to take into account synchronized vector measurements of angles at voltages and require modification. The article presents a modified algorithm developed on the basis of the Gauss–Newton method, making it possible to use telemeasurements and synchronized vector measurements together, to evaluate the impact errors in synchronized vector measurements of angles at voltages on assessing the mode parameters, to determine allowable error intervals according to conditions of ensuring correct estimation mode parameters, to make the conclusion on advisability to use synchronized vector dimensions of angles in solving the problem of state assessing. The algorithm is tested using computational experiments when evaluating such mode parameters as active and reactive load power, voltage module, power flows. On the basis of studies, the error intervals of angles have been revealed, beyond which taking into account the angles at voltages will contribute to improving the accuracy of state estimation. The parameters of the mode that are the most sensory to the increase of errors in synchronized vector measurements of angles are determined.

2020 ◽  
Vol 19 (6) ◽  
pp. 1154-1172
Author(s):  
Yu.V. Granitsa

Subject. The article addresses projections of regional budget revenues, using distributed lag models. Objectives. The purpose is to review economic and statistical tools that are suitable for the analysis of relationship between the revenues of the regional budget system and regional macroeconomic predictors. Methods. The study draws on statistical, constructive, economic and mathematical methods of analysis. Results. In models with quantitative variables obtained under the Almon method, the significant predictors in the forecasting of regional budget revenues are determined mainly by the balanced financial result, the consumer price index, which characterizes inflation processes in the region, and the unemployment rate being the key indicator of the labor market. Models with quantitative variables obtained through the Koyck transformation are characterized by a wider range of predictors, the composition of which is determined by the peculiarities of economic situation in regions. The two-year forecast provides the average lag obtained during the evaluation of the models. The exception is the impact of unemployment rate, which is characterized as long-term. Conclusions. To generate forecasts of budget parameters, the results of both the Koyck method and the Almon method should be considered, though the former is more promising.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3274
Author(s):  
Jose Rueda Torres ◽  
Zameer Ahmad ◽  
Nidarshan Veera Kumar ◽  
Elyas Rakhshani ◽  
Ebrahim Adabi ◽  
...  

Future electrical power systems will be dominated by power electronic converters, which are deployed for the integration of renewable power plants, responsive demand, and different types of storage systems. The stability of such systems will strongly depend on the control strategies attached to the converters. In this context, laboratory-scale setups are becoming the key tools for prototyping and evaluating the performance and robustness of different converter technologies and control strategies. The performance evaluation of control strategies for dynamic frequency support using fast active power regulation (FAPR) requires the urgent development of a suitable power hardware-in-the-loop (PHIL) setup. In this paper, the most prominent emerging types of FAPR are selected and studied: droop-based FAPR, droop derivative-based FAPR, and virtual synchronous power (VSP)-based FAPR. A novel setup for PHIL-based performance evaluation of these strategies is proposed. The setup combines the advanced modeling and simulation functions of a real-time digital simulation platform (RTDS), an external programmable unit to implement the studied FAPR control strategies as digital controllers, and actual hardware. The hardware setup consists of a grid emulator to recreate the dynamic response as seen from the interface bus of the grid side converter of a power electronic-interfaced device (e.g., type-IV wind turbines), and a mockup voltage source converter (VSC, i.e., a device under test (DUT)). The DUT is virtually interfaced to one high-voltage bus of the electromagnetic transient (EMT) representation of a variant of the IEEE 9 bus test system, which has been modified to consider an operating condition with 52% of the total supply provided by wind power generation. The selected and programmed FAPR strategies are applied to the DUT, with the ultimate goal of ascertaining its feasibility and effectiveness with respect to the pure software-based EMT representation performed in real time. Particularly, the time-varying response of the active power injection by each FAPR control strategy and the impact on the instantaneous frequency excursions occurring in the frequency containment periods are analyzed. The performed tests show the degree of improvements on both the rate-of-change-of-frequency (RoCoF) and the maximum frequency excursion (e.g., nadir).


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1688 ◽  
Author(s):  
C. Birk Jones ◽  
Matthew Lave ◽  
William Vining ◽  
Brooke Marshall Garcia

An increase in Electric Vehicles (EV) will result in higher demands on the distribution electric power systems (EPS) which may result in thermal line overloading and low voltage violations. To understand the impact, this work simulates two EV charging scenarios (home- and work-dominant) under potential 2030 EV adoption levels on 10 actual distribution feeders that support residential, commercial, and industrial loads. The simulations include actual driving patterns of existing (non-EV) vehicles taken from global positioning system (GPS) data. The GPS driving behaviors, which explain the spatial and temporal EV charging demands, provide information on each vehicles travel distance, dwell locations, and dwell durations. Then, the EPS simulations incorporate the EV charging demands to calculate the power flow across the feeder. Simulation results show that voltage impacts are modest (less than 0.01 p.u.), likely due to robust feeder designs and the models only represent the high-voltage (“primary”) system components. Line loading impacts are more noticeable, with a maximum increase of about 15%. Additionally, the feeder peak load times experience a slight shift for residential and mixed feeders (≈1 h), not at all for the industrial, and 8 h for the commercial feeder.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1387
Author(s):  
Oswaldo Sebastian Peñaherrera-Pulla ◽  
Carlos Baena ◽  
Sergio Fortes ◽  
Eduardo Baena ◽  
Raquel Barco

Cloud Gaming is a cutting-edge paradigm in the video game provision where the graphics rendering and logic are computed in the cloud. This allows a user’s thin client systems with much more limited capabilities to offer a comparable experience with traditional local and online gaming but using reduced hardware requirements. In contrast, this approach stresses the communication networks between the client and the cloud. In this context, it is necessary to know how to configure the network in order to provide service with the best quality. To that end, the present work defines a novel framework for Cloud Gaming performance evaluation. This system is implemented in a real testbed and evaluates the Cloud Gaming approach for different transport networks (Ethernet, WiFi, and LTE (Long Term Evolution)) and scenarios, automating the acquisition of the gaming metrics. From this, the impact on the overall gaming experience is analyzed identifying the main parameters involved in its performance. Hence, the future lines for Cloud Gaming QoE-based (Quality of Experience) optimization are established, this way being of configuration, a trendy paradigm in the new-generation networks, such as 4G and 5G (Fourth and Fifth Generation of Mobile Networks).


2015 ◽  
Vol 25 (12) ◽  
pp. 1550167
Author(s):  
Lei Wang ◽  
Hsiao-Dong Chiang

This paper presents online methods for controlling local bifurcations of power grids with the goal of increasing bifurcation values (i.e. increasing load margins) via network topology optimization, a low-cost control. In other words, this paper presents online methods for increasing power transfer capability subject to static stability limit via switching transmission line out/in (i.e. disconnecting a transmission line or connecting a transmission line). To illustrate the impact of network topology on local bifurcations, two common local bifurcations, i.e. saddle-node bifurcation and structure-induced bifurcation on small power grids with different network topologies are shown. A three-stage online control methodology of local bifurcations via network topology optimization is presented to delay local bifurcations of power grids. Online methods must meet the challenging requirements of online applications such as the speed requirement (in the order of minutes), accuracy requirement and robustness requirement. The effectiveness of the three-stage methodology for online applications is demonstrated on the IEEE 118-bus and a 1648-bus practical power systems.


2021 ◽  
Vol 3 (2) ◽  
pp. 409-423
Author(s):  
Ayman Awad ◽  
Hussein Abdel-Mawgoud ◽  
Salah Kamel ◽  
Abdalla A. Ibrahim ◽  
Francisco Jurado

Distributed generation (DG) is becoming a prominent key spot for research in recent years because it can be utilized in emergency/reserve plans for power systems and power quality improvement issues, besides its drastic impact on the environment as a greenhouse gas (GHG) reducer. For maximizing the benefits from such technology, it is crucial to identify the best size and location for DG that achieves the required goal of installing it. This paper presents an investigation of the optimized allocation of DG in different modes using a proposed hybrid technique, the tunicate swarm algorithm/sine-cosine algorithm (TSA/SCA). This investigation is performed on an IEEE-69 Radial Distribution System (RDS), where the impact of such allocation on the system is evaluated by NEPLAN software.


Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 108
Author(s):  
Dong Qin ◽  
Yuhao Wang ◽  
Tianqing Zhou

This paper investigates the impact of cooperative spectrum sharing policy on the performance of hybrid radio frequency and free space optical wireless communication networks, where primary users and secondary users develop a band of the same spectrum resource. The radio frequency links obey Nakagami-m distribution with arbitrary fading parameter m, while the free space optical link follows gamma-gamma distributed atmospheric turbulence with nonzero pointing error. Because the secondary users access the spectrum band without payment, their behavior needs to be restricted. Specifically, the power of the secondary users is dominated by the tolerable threshold of the primary users. Considering both heterodyne and intensity modulation/direct detection strategies in optical receiver, the performance of optical relaying networks is completely different from that of traditional networks. With the help of bivariable Fox’s H function, new expressions for cumulative distribution function of equivalent signal to noise ratio at destination, probability density function, outage probability, ergodic capacity and symbol error probability are built in closed forms.


2018 ◽  
Vol 3 (3/4) ◽  
pp. 139-152
Author(s):  
Hatem Adela

Purpose This paper aims to contribute to formulating the methodological framework for a paradigm of Islamic economics, using the development of the conventional economics, theoretical and mathematical methods. Design/methodology/approach The study based on the inductive and mathematical methods to contribute to economic theory within the methodological framework for Islamic Economics, by using the return rate of Musharakah rather than the interest rate in influence the economic activity and monetary policy. Findings Via replacement, the concept of the interest rate by the return rates of Musharakah. It concludes that the central bank can control the monetary policy, economic activity and the efficient allocation of resources by using the return rates of Musharakah through the framework of Islamic economy. Practical/implications The study is a contribution to formulate the methodological framework for a paradigm of Islamic economics, where it investigates the impact of return rates of Musharakah on the money market and monetary policy, by the mathematical methods used in the conventional economy. Also, the study illustrates the importance of further studies that examine the methodological framework for Islamic Economics. Originality/value The study aims to contribute to formulating the Islamic economic theory, through the return rate of Musharakah financing instead of the interest rate, and its effectiveness of the monetary policy. As well as reformulating the concepts of the investment function, the present value and the marginal efficiency rate of investment according to the Islamic economy approach.


2014 ◽  
Vol 513-517 ◽  
pp. 772-776
Author(s):  
Chen Wang ◽  
Hong Ai ◽  
Lie Wu ◽  
Yun Yang

The smart grid that the next-generation electric power system is studied intensively as a promising solution for energy crisis. One important feature of the smart grid is the integration of high-speed, reliable and secure data communication networks to manage the complex power systems effectively and intelligently. The goal of smart grid is to achieve the security of operation, economic efficient and environmental friendly. To achieve this goal, we proposed a fine-grained access control model for smart grid. In order to improve the security of smart grid, an access-trust-degree algorithm is proposed to evaluate the reliability of the user who want to access to the smart grid.


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