scholarly journals Application of Solid-State Transformers in a Novel Architecture of Hybrid AC/DC House Power Systems

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3432 ◽  
Author(s):  
Fabio Bignucolo ◽  
Manuele Bertoluzzo
Keyword(s):  
Solid State ◽  
Power Systems ◽  
Distribution Networks ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Dynamic Simulations ◽  
Load Variations ◽  
Solid State Transformers ◽  
Local Resources ◽  
Induction Cooking

The ongoing diffusion of solid-state DC/DC converters makes possible a partial migration of electric power systems from the present AC paradigm to a future DC scenario. In addition, the power demand in the domestic environment is expected to grow considerably, for example, due to the progressive diffusion of electric vehicles, induction cooking and heat pumps. To face this evolution, the paper introduces a novel electric topology for a hybrid AC/DC smart house, based on the solid-state transformer technology. The electric scheme, voltage levels and converters types are thoroughly discussed to better integrate the spread of electric appliances, which are frequently based on internal DC buses, within the present AC distribution networks. Voltage levels are determined to guarantee high safety zones with negligible electric risk in the most exposed areas of the house. At the same time, the developed control schemes assure high power quality (voltage stability in the case of both load variations and network perturbations), manage power flows and local resources according to ancillary services requirements and increase the domestic network overall efficiency. Dynamic simulations are performed, making use of DIgSILENT PowerFactory software, to demonstrate the feasibility of the proposed distribution scheme for next-generation smart houses under different operating conditions.

scholarly journals Solid State Transformers: Concepts, Classification, and Control

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2319 ◽  
Author(s):  
Mohammed Azharuddin Shamshuddin ◽  
Felix Rojas ◽  
Roberto Cardenas ◽  
Javier Pereda ◽  
Matias Diaz ◽  
...  
Keyword(s):  
Solid State ◽  
Power Distribution ◽  
Smart Grids ◽  
Energy Demand ◽  
Material Selection ◽  
Distribution Networks ◽  
Renewable Energy Resources ◽  
Power Sources ◽  
Solid State Transformers ◽  
And Control

Increase in global energy demand and constraints from fossil fuels have encouraged a growing share of renewable energy resources in the utility grid. Accordingly, an increased penetration of direct current (DC) power sources and loads (e.g., solar photovoltaics and electric vehicles) as well as the necessity for active power flow control has been witnessed in the power distribution networks. Passive transformers are susceptible to DC offset and possess no controllability when employed in smart grids. Solid state transformers (SSTs) are identified as a potential solution to modernize and harmonize alternating current (AC) and DC electrical networks and as suitable solutions in applications such as traction, electric ships, and aerospace industry. This paper provides a complete overview on SST: concepts, topologies, classification, power converters, material selection, and key aspects for design criteria and control schemes proposed in the literature. It also proposes a simple terminology to identify and homogenize the large number of definitions and structures currently reported in the literature.

scholarly journals Resilient and Immune by Design Microgrids Using Solid State Transformers

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3377 ◽  
Author(s):  
Mihai Sanduleac ◽  
João Martins ◽  
Irina Ciornei ◽  
Mihaela Albu ◽  
Lucian Toma ◽  
...  
Keyword(s):  
Solid State ◽  
Power System ◽  
New Technologies ◽  
Low Voltage ◽  
Distribution Networks ◽  
Electrostatic Energy ◽  
Time Interval ◽  
Solid State Transformers ◽  
Stability Point ◽  
Bulk Power

Solid State Transformers (SST) may become, in the near future, key technological enablers for decentralized energy supply systems. They have the potential to unleash new technologies and operation strategies of microgrids and prosumers to move faster towards a low carbon-based economy. This work proposes a paradigm change in the hierarchically and distributed operated power systems where SSTs are used to asynchronously connect the many small low voltage (LV) distribution networks, such as clusters of prosumers or LV microgrids, to the bulk power system. The need for asynchronously coupled microgrids requires a design that allows the LV system to operate independently from the bulk grid and to rely on its own control systems. The purpose of this new approach is to achieve immune and resilient by design configurations that allow maximizing the integration of Local Renewable Energy Resources (L-RES). The paper analyses from the stability point of view, through simplified numerical simulations, the way in which SST-interconnected microgrids can become immune to disturbances that occur in the bulk power system and how sudden changes in the microgrid can damp out at the Point of Common Coupling (PCC), thus achieving better reliability and predictability in both systems and enabling strong and healthy distributed energy storage systems (DESSs). Moreover, it is shown that in a fully inverter-based microgrid there is no need for mechanical or synthetic inertia to stabilize the microgrid during power unbalances. This happens because the electrostatic energy stored in the capacitors connected behind the SST inverter can be used for a brief time interval, until automation is activated to address the power unbalance for a longer term.

scholarly journals Design Optimisation of a Current-Fed Solid-State Transformer for MV Grid-Connected Applications

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3283
Author(s):  
Essam Hussain ◽  
Mohammad Abusara ◽  
Suleiman Sharkh
Keyword(s):  
Solid State ◽  
Flux Density ◽  
Holistic Approach ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Power Losses ◽  
Solid State Transformer ◽  
Design Optimisation ◽  
Solid State Transformers ◽  
Main Components

For integrating large batteries in the medium voltage grid, current fed solid-state transformers offer galvanic isolation and a significant weight and size reduction. While the power losses increase with frequency and flux density, the core volume is contrariwise. Therefore, a design optimisation to achieve minimum losses and/or a minimum volume is essential. An optimisation strategy is proposed in this paper to find the optimum operating frequency and core flux density under certain practical constraints such as winding voltage per turn, clearance between transformer windings, saturation flux density and minimum efficiency. Differently from previous works, the proposed strategy provides a holistic approach for the design considering all main power losses from all main components using nonsinusoidal voltage waveforms and different operating conditions. Analytical equations for the power losses calculation and the cores design are derived and validated using ANSYS and MATLAB Simulink software packages. Simulation results of the power loss calculation under different operating frequencies and duty cycles are presented and compared with the analytical results. A case study for designing a 1.0 MW, 0.6/18 kV current fed solid-state transformer is presented. The results of two optimisation objectives, minimum power losses or minimum total cores housing volume are also shown.

Optimal Placement of FACTS Devices for Voltage Stability Improvement with Economic Consideration Using Firefly Algorithm

2019 ◽  
Vol 14 (1) ◽  
pp. 5-11
Author(s):  
S. Rajasekaran ◽  
S. Muralidharan
Keyword(s):  
Power Systems ◽  
Voltage Stability ◽  
Firefly Algorithm ◽  
Transmission System ◽  
Operating Conditions ◽  
Optimal Placement ◽  
Voltage Collapse ◽  
Facts Devices ◽  
The Cost ◽  
Bus System

Background: Increasing power demand forces the power systems to operate at their maximum operating conditions. This leads the power system into voltage instability and causes voltage collapse. To avoid this problem, FACTS devices have been used in power systems to increase system stability with much reduced economical ratings. To achieve this, the FACTS devices must be placed in exact location. This paper presents Firefly Algorithm (FA) based optimization method to locate these devices of exact rating and least cost in the transmission system. Methods: Thyristor Controlled Series Capacitor (TCSC) and Static Var Compensator (SVC) are the FACTS devices used in the proposed methodology to enhance the voltage stability of power systems. Considering two objectives of enhancing the voltage stability of the transmission system and minimizing the cost of the FACTS devices, the optimal ratings and cost were identified for the devices under consideration using Firefly algorithm as an optimization tool. Also, a model study had been done with four different cases such as normal case, line outage case, generator outage case and overloading case (140%) for IEEE 14,30,57 and 118 bus systems. Results: The optimal locations to install SVC and TCSC in IEEE 14, 30, 57 and 118 bus systems were evaluated with minimal L-indices and cost using the proposed Firefly algorithm. From the results, it could be inferred that the cost of installing TCSC in IEEE bus system is slightly higher than SVC.For showing the superiority of Firefly algorithm, the results were compared with the already published research finding where this problem was solved using Genetic algorithm and Particle Swarm Optimization. It was revealed that the proposed firefly algorithm gives better optimum solution in minimizing the L-index values for IEEE 30 Bus system. Conclusion: The optimal placement, rating and cost of installation of TCSC and SVC in standard IEEE bus systems which enhanced the voltage stability were evaluated in this work. The need of the FACTS devices was also tested during the abnormal cases such as line outage case, generator outage case and overloading case (140%) with the proposed Firefly algorithm. Outputs reveal that the recognized placement of SVC and TCSC reduces the probability of voltage collapse and cost of the devices in the transmission lines. The capability of Firefly algorithm was also ensured by comparing its results with the results of other algorithms.

Experimental and numerical analysis to identify the performance limiting mechanisms in solid-state lithium cells under pulse operating conditions

2019 ◽  
Vol 21 (41) ◽  
pp. 22740-22755 ◽  
Author(s):  
Mei-Chin Pang ◽  
Yucang Hao ◽  
Monica Marinescu ◽  
Huizhi Wang ◽  
Mu Chen ◽  
...  
Keyword(s):  
Solid State ◽  
Numerical Analysis ◽  
Energy Density ◽  
Lithium Ion Batteries ◽  
Lithium Batteries ◽  
Safety Concern ◽  
Lithium Ion ◽  
Thermal Runaway ◽  
Operating Conditions ◽  
Lithium Cells

Solid-state lithium batteries could reduce the safety concern due to thermal runaway while improving the gravimetric and volumetric energy density beyond the existing practical limits of lithium-ion batteries.

scholarly journals Selection of Heat Pump Capacity Used at Thermal Power Plants under Electricity Market Operating Conditions

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 226
Author(s):  
Milana Treshcheva ◽  
Irina Anikina ◽  
Vitaly Sergeev ◽  
Sergey Skulkin ◽  
Dmitry Treshchev
Keyword(s):  
Electric Power ◽  
Heat Pump ◽  
Heat Load ◽  
Power Plants ◽  
Thermal Power ◽  
Heat Pumps ◽  
Operating Conditions ◽  
Energy Resources ◽  
Thermal Power Plants ◽  
Maximum Heat

The percentage of heat pumps used in thermal power plants (TPPs) in the fuel and energy balance is extremely low in in most countries. One of the reasons for this is the lack of a systematic approach to selecting and justifying the circuit solutions and equipment capacity. This article aims to develop a new method of calculating the maximum capacity of heat pumps. The method proposed in the article has elements of marginal analysis. It takes into account the limitation of heat pump capacity by break-even operation at electric power market (compensation of fuel expenses, connected with electric power production). In this case, the heat pump’s maximum allowable capacity depends on the electric capacity of TPP, electricity consumption for own needs, specific consumption of conditional fuel for electricity production, a ratio of prices for energy resources, and a conversion factor of heat pump. For TPP based on combined cycle gas turbine (CCGT) CCGT-450 with prices at the Russian energy resources markets at the level of 2019, when operating with the maximum heat load, the allowable heat pump capacity will be about 50 MW, and when operating with the minimum heat load—about 200 MW.

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