A research into the operation of a system of electric energy accumulation as part of a cyber-physical real time simulation facility

2020 ◽  
Vol 2 (4) ◽  
pp. 209-218
Author(s):  
A. G. Volkov ◽  
D. A. Sagaiko

Introduction: the frequency and capacity control, as well as the maintenance of electric energy systems rely on the choice of the items of equipment that comprise a particular electric energy system. Generators are the core items of equipment comprising traditional electricity systems, while in off-grid electricity systems this function is assumed by the power-driven converter equipment coupled with energy accumulation systems. The main problem of these systems consists in a fast response generated by the power-driven converter equipment to the changing environment. Excessively fast responses, given by the controllers, make the whole off-grid electricity system unstable.Methods: the resolution of the problem of an unstable off-grid electricity system requires the use of algorithms for the control over inverters and frequency converters, designed according to the principle of a virtual synchronous machine that applies voltage and frequency droops. The model of an electricity system has been produced. It has six key elements: a basic balancing inverter, two generators, lithium-oil battery simulation, an interface converter and a real time digital simulator (RTDS). The model was used to perform an experiment to implement two-way data transmission from RTDS to converting facilities and to verify the performance capability of the algorithm and the electricity system as a whole.Results and discussion: as a result of this experiment, the contact was made between RTDS, Generator 1, Generator 2 and the basic balancing inverter through interface converters. This electricity system is resilient and failure-free.Conclusion: data communication was organized between the real time module of digital simulation and Generator 2. Control commands were delivered from the digital simulation module through interface converters, and their execution monitoring was used as a feedback. The operation of grid-forming and grid-filling converters of a self-contained electricity system was stand tested at the MIPT Centre for Engineering, and optimization algorithm performance results were obtained in respect of a battery used in the course of the application of virtual synchronous machines.

2021 ◽  
Vol 9 ◽  
Author(s):  
Johanna Olovsson ◽  
Maria Taljegard ◽  
Michael Von Bonin ◽  
Norman Gerhardt ◽  
Filip Johnsson

This study analyses the impacts of electrification of the transport sector, involving both static charging and electric road systems (ERS), on the Swedish and German electricity systems. The impact on the electricity system of large-scale ERS is investigated by comparing the results from two model packages: 1) a modeling package that consists of an electricity system investment model (ELIN) and electricity system dispatch model (EPOD); and 2) an energy system investment and dispatch model (SCOPE). The same set of scenarios are run for both model packages and the results for ERS are compared. The modeling results show that the additional electricity load arising from large-scale implementation of ERS is mainly, depending on model and scenario, met by investments in wind power in Sweden (40–100%) and in both wind (20–75%) and solar power (40–100%) in Germany. This study also concludes that ERS increase the peak power demand (i.e., the net load) in the electricity system. Therefore, when using ERS, there is a need for additional investments in peak power units and storage technologies to meet this new load. A smart integration of other electricity loads than ERS, such as optimization of static charging at the home location of passenger cars, can facilitate efficient use of renewable electricity also with an electricity system including ERS. A comparison between the results from the different models shows that assumptions and methodological choices dictate which types of investments are made (e.g., wind, solar and thermal power plants) to cover the additional demand for electricity arising from the use of ERS. Nonetheless, both modeling packages yield increases in investments in solar power (Germany) and in wind power (Sweden) in all the scenarios, to cover the new electricity demand for ERS.


Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4666 ◽  
Author(s):  
Bingda Zhang ◽  
Xianglong Jin ◽  
Sijia Tu ◽  
Zhao Jin ◽  
Jie Zhang

Considering the rational use of field programmable gate array (FPGA) resources, this paper proposes a new FPGA-based real-time digital solver (FRTDS) for power system simulation. Based on the relationship between the number of computing components, the operating frequency, and the pipeline length, the best selection principle is given. By analyzing the implementation method of the Multi-Port Read/Write Circuit, the computing formula of the Look-Up-Table (LUT) consumption was derived. Given the excessive use of LUTs in the original computing components, the computing components were assembled in a single typical arithmetic expression of the power system simulation program, as the basic computing formula was characterized by a subset of the typical computing formula and multiple uses of the same variable. Data communication between different computing components was realized by using Multi-Port Input Circuits that share some outputs of read controller, and Multi-Port Output Circuits, which share some outputs of computing cores. According to the test results of original FRTDS and new FRTDS, it was found that the solution proposed in this paper had a shorter ideal simulation time and a higher parallel computing capability, which was very suitable for real-time digital simulation of power systems.


2020 ◽  
Vol 8 (3) ◽  
pp. 162-172
Author(s):  
Eberhard Rothfuß ◽  
Festus Boamah

Dominant electricity systems are inevitably transitioning into new forms in terms of power generation mix, mode of energy system governance and vested interests, the extent of state and consumer/citizen participation in the energy system, and energy justice expectations in different geographies in the Global North and Global South. In this editorial to the thematic issue entitled <em>Politics and (Self-)Organisation of Electricity System Transitions in a Global North–South Perspective</em>, we discuss politics and (self)-organisation of (just) energy transitions to expose how messy, convoluted, and fluid future electricity system transitions can be in both the Global North and Global South.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8404
Author(s):  
Janailson Queiroz ◽  
Sarah Carvalho ◽  
Camila Barros ◽  
Luciano Barros ◽  
Daniel Barbosa

Real-Time Digital Simulation (RTDS) is a powerful tool in modeling and analyzing electrical and drive systems because it provides an efficient and accurate process. There are several hardware devices for this type of simulation; however, their high costs have led to the increasing use of more affordable and reconfigurable technologies. In this context, many logic blocks and storage elements make the Field Programmable Gate Array (FPGA) an ideal device to perform RTDS. This work proposes a technique to embed a real-time digital simulator in an FPGA through Hardware Description Language (HDL) since it provides liberty in the architecture choice and no dependency on commercial ready-made hardware–software packages. The approach proposed focuses on system design developing with expression tree graph, synthesizing and verifying, prioritizing the performance and design accuracy concerning area and power consumption. Thus, the result acquisition occurs at a time step considered in real-time. A simulation of a direct current (DC) motor speed control has been incorporated into this work as an example of application, which includes the embedding and simulation of the electric machine and its drive system. Performance tests have shown that the developed simulator is real-time and makes possible realistic analysis of the interaction between the plant and its control. In addition, an idea of the hardware requirement for real-time simulation is proposed based on the number of mathematical operations.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 593
Author(s):  
Moiz Muhammad ◽  
Holger Behrends ◽  
Stefan Geißendörfer ◽  
Karsten von Maydell ◽  
Carsten Agert

With increasing changes in the contemporary energy system, it becomes essential to test the autonomous control strategies for distributed energy resources in a controlled environment to investigate power grid stability. Power hardware-in-the-loop (PHIL) concept is an efficient approach for such evaluations in which a virtually simulated power grid is interfaced to a real hardware device. This strongly coupled software-hardware system introduces obstacles that need attention for smooth operation of the laboratory setup to validate robust control algorithms for decentralized grids. This paper presents a novel methodology and its implementation to develop a test-bench for a real-time PHIL simulation of a typical power distribution grid to study the dynamic behavior of the real power components in connection with the simulated grid. The application of hybrid simulation in a single software environment is realized to model the power grid which obviates the need to simulate the complete grid with a lower discretized sample-time. As an outcome, an environment is established interconnecting the virtual model to the real-world devices. The inaccuracies linked to the power components are examined at length and consequently a suitable compensation strategy is devised to improve the performance of the hardware under test (HUT). Finally, the compensation strategy is also validated through a simulation scenario.


Author(s):  
Wolf Schulze ◽  
Maurizio Zajadatz ◽  
Michael Suriyah ◽  
Thomas Leibfried

AbstractA test bed for the evaluation of novel control methods of inverters for renewable power generation is presented. The behavior of grid-following and grid-forming control in a test scenario is studied and compared.Using a real-time capable control platform with a cycle time of 50 µs, control methods developed with Matlab/Simulink can be implemented. For simplicity, a three-phase 4‑quadrant voltage amplifier is used instead of an inverter. Thus, the use of modulation and switched power semiconductors can be avoided. In order to show a realistic behavior of a grid-side filter, passive components can be automatically connected as L‑, LC- or LCL-filter. The test bed has a nominal active power of 43.6 kW and a nominal voltage of 400 V.As state-of-the-art grid-following control method, a current control in the d/q-system is implemented in the test bed. A virtual synchronous machine, the Synchronverter, is used as grid-forming control method. In combination with a frequency-variable grid emulation, the behavior of both control methods is studied in the event of a load connection in an island grid environment.


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