scholarly journals Frequency-Domain Nonlinear Modeling Approaches for Power Systems Components—A Comparison

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2609
Author(s):  
Marco Faifer ◽  
Christian Laurano ◽  
Roberto Ottoboni ◽  
Sergio Toscani ◽  
Michele Zanoni

Harmonic simulations play a key role in studying and predicting the impact of nonlinear devices on the power quality level of distribution grids. A frequency-domain approach allows higher computational efficiency, which has key importance as long as complex networks have to be studied. However, this requires proper frequency-domain behavioral models able to represent the nonlinear voltage–current relationship characterizing these devices. The Frequency Transfer Matrix (FTM) method is one of the most widespread frequency domain modeling approaches for power system applications. However, others suitable techniques have been developed in the last years, in particular the X-parameters approach, which comes from radiofrequency and microwave applications, and the simplified Volterra models under quasi-sinusoidal conditions, that have been specifically tailored for power system devices. In this paper FTM, X-parameters and simplified Volterra approaches are compared in representing the nonlinear voltage –current relationship of a bridge rectifier feeding an ohmic-capacitive dc load. Results show that the X-parameters model reaches good accuracy, which is slightly better than that achieved by the FTM and simplified Volterra models, but with a considerably larger set of coefficients. Simplified Volterra models under quasi-sinusoidal conditions allows an effective trade-off between accuracy and complexity.

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3310 ◽  
Author(s):  
Ignacio Blanco ◽  
Daniela Guericke ◽  
Anders Andersen ◽  
Henrik Madsen

In countries with an extended use of district heating (DH), the integrated operation of DH and power systems can increase the flexibility of the power system, achieving a higher integration of renewable energy sources (RES). DH operators can not only provide flexibility to the power system by acting on the electricity market, but also profit from the situation to lower the overall system cost. However, the operational planning and bidding includes several uncertain components at the time of planning: electricity prices as well as heat and power production from RES. In this publication, we propose a planning method based on stochastic programming that supports DH operators by scheduling the production and creating bids for the day-ahead and balancing electricity markets. We apply our solution approach to a real case study in Denmark and perform an extensive analysis of the production and trading behavior of the DH system. The analysis provides insights on system costs, how DH system can provide regulating power, and the impact of RES on the planning.


1999 ◽  
Vol 23 (1B) ◽  
pp. 117-127
Author(s):  
R. Lykins ◽  
M. Ramalingam ◽  
B. Donovan ◽  
E. Durkin ◽  
J. Beam

A computerized analytical program is being developed to help investigate the impact of power system requirements on aircraft performance. The program has an user interface that operates in MS-EXCEL, linking several subsystems analysis programs for execution and data transfer in the power systems analysis. The program presently includes an encoded propulsion engine cycle code, which allows the inspection of power extraction effects on engine performance. To validate the results of the encoded engine program, a study was conducted to investigate the separate effects of shaft power extraction and pneumatic bleed. The selected engine cycle was that for a standard tactical fighter, with a flight condition of varied altitude (sea level to 40,000 ft) and constant Mach Number (0.9). As expected the resultant data showed that the engine performance was more sensitive to pneumatic bleed than to shaft power extraction. The paper’s efficiency comparisons between shaft power and bleed air power helps indicate the higher efficiency for the power system of a more-electric type aircraft. Present efforts on the analytical interface are to incorporate a fuel thermal management analysis capability.


Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2268 ◽  
Author(s):  
Dong-Hee Yoon ◽  
Sang-Kyun Kang ◽  
Minseong Kim ◽  
Youngsun Han

We present a novel architecture of parallel contingency analysis that accelerates massive power flow computation using cloud computing. It leverages cloud computing to investigate huge power systems of various and potential contingencies. Contingency analysis is undertaken to assess the impact of failure of power system components; thus, extensive contingency analysis is required to ensure that power systems operate safely and reliably. Since many calculations are required to analyze possible contingencies under various conditions, the computation time of contingency analysis increases tremendously if either the power system is large or cascading outage analysis is needed. We also introduce a task management optimization to minimize load imbalances between computing resources while reducing communication and synchronization overheads. Our experiment shows that the proposed architecture exhibits a performance improvement of up to 35.32× on 256 cores in the contingency analysis of a real power system, i.e., KEPCO2015 (the Korean power system), by using a cloud computing system. According to our analysis of the task execution behaviors, we confirmed that the performance can be enhanced further by employing additional computing resources.


2014 ◽  
Vol 672-674 ◽  
pp. 227-232
Author(s):  
Xu Zhi Luo ◽  
Hai Feng Li ◽  
Hua Dong Sun ◽  
An Si Wang ◽  
De Zhi Chen

With the fast development of the wind power, security constraints of power systems have become the bottleneck of the acceptable capacity for wind power. The underdamping oscillation modes of the inter-area is an important aspect of the constraints. In this paper, an equivalent model of a power system with wind plants has been established, and the impact of the integration of the large-scale wind power on the inter-area oscillation modes has been studied based on the frequency-domain and time-domain simulations. The results indicate that the damping of inter-area oscillation mode can be enhanced by the replacement of synchronous generators (SGs) with the wind generators. The enhancing degree is up to the participation value of the SGs replaced. The conclusion has been verified by the actual system example of Xinjiang-Northwest grid. It can provide a reference for system programming and operation.


Author(s):  
W Edge ◽  
R Partridge ◽  
E Maxeiner

The next generation of large surface combatants will feature a number of challenging hurdles with regards to performance, complexity and capability whilst being mindful of tomorrow’s fiscal pressures. Over the past two decades, new warship programmes have focussed on more complex, multi-role capabilities necessitating more adaptable mission and platform systems. With tomorrow’s vessels facing a service life between 35-50 years the selected power systems need to be sympathetic of today’s requirements as well as through life technology insertion for tomorrow’s needs. To facilitate this, a number of tomorrow’s warships are looking to adopt an all-electric architecture making use of developing energy storage technologies and more power dense prime movers. Whilst this in itself is no revelation, the impact that electric weapons and sensors have on an electrical power system, as well as the added costs incurred through provision of electrical margins, means it becomes imperative that design experience, lessons learnt, and evolving technologies are all considered during the concept design phase. Electrification of warships has been commonplace since the early 1990s and in-service experiences on platforms with Integrated Power Systems (IPS) are now informing the requirement set for their replacement vessels. The DDG1000 Destroyer as an example, at sea since 2013, has yielded some valuable insights in areas of design optimisation and resilience that can benefit future combatant types. These experiences and the proven products on board these vessels will be augmented by new technologies and configured as part of new architectures to service the new types of loads that accompany the deployment of high energy weapons and sensors. Meeting these demands in an affordable, efficient, resilient and reliable manner will be key to ensuring the future platform’s success and longevity. This paper aims to visit the key in-service experiences of today’s all electric ships whilst considering core aspects of future ‘second generation’ all electric ship design. This will include the need for power system ‘granularity’; investigating the building blocks of power generation that make up these complex systems, whilst analysing the maturity of their constituent parts and the enabling technologies that make these systems possible.


2019 ◽  
Vol 114 ◽  
pp. 05007 ◽  
Author(s):  
Felix Byk ◽  
Yana Frolova ◽  
Ludmila Myshkina

The existing centralized power supply system has the alternative due to distributed generation. By certain conditions distributed cogeneration allows to increase the reliability and quality of power supply and to reduce the cost of electricity for consumers. Therefore, a lot of energy-intensive consumers switched to their own power supply systems, as it turned out to be a competitive technical solution. The total gasification of the country’s regions and the presence of domestic manufacturers of gas turbine and gas piston power plants accelerated this process. Nowadays local power systems are emerging with cogeneration plants are the main source of heat and electricity there. The feasibility justification of the kind and type of generation is determined by many factors, including circuit-mode parameters in the local power system and adjacent network. Local power systems based on the principles of self-balance are proposed to name as energy cells. The integration of energy cells with regional power system increases the technical and economic effectiveness of power supply system for consumers. The proposed power systems transition leads to certain systemic effects. Received effects are depending on functions of distributed generation. This paper explores the impact of scheme and mode factor on the technical effects.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3219 ◽  
Author(s):  
Martin Ćalasan ◽  
Tatjana Konjić ◽  
Katarina Kecojević ◽  
Lazar Nikitović

In the current age, power systems contain many modern elements, one example being Flexible AC Transmission System (FACTS) devices, which play an important role in enhancing the static and dynamic performance of the systems. However, due to the high costs of FACTS devices, the location, type, and value of the reactive power of these devices must be optimized to maximize their resulting benefits. In this paper, the problem of optimal power flow for the minimization of power losses is considered for a power system with or without a FACTS controller, such as a Static Var Compensator (SVC) device The impact of location and SVC reactive power values on power system losses are considered in power systems with and without the presence of wind power. Furthermore, constant and variable load are considered. The mentioned investigation is realized on both IEEE 9 and IEEE 30 test bus systems. Optimal SVC allocation are performed in program GAMS using CONOPT solver. For constant load data, the obtained results of an optimal SVC allocation and the minimal value of power losses are compared with known solutions from the literature. It is shown that the CONOPT solver is useful for finding the optimal location of SVC devices in a power system with or without the presence of wind energy. The comparison of results obtained using CONOPT solver and four metaheuristic method for minimization of power system losses are also investigated and presented.


2021 ◽  
Vol 17 (2) ◽  
pp. 27-37
Author(s):  
Ahmed Abbas ◽  
Mazyed Al-Tak

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


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