scholarly journals Multi-State Reliability Assessment Model of Base-Load Cyber-Physical Energy Systems (CPES) during Flexible Operation Considering the Aging of Cyber Components

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3241
Author(s):  
Zhaojun Hao ◽  
Francesco Di Maio ◽  
Enrico Zio

Cyber-Physical Energy Systems (CPESs) are energy systems which rely on cyber components for energy production, transmission and distribution control, and other functions. With the penetration of Renewable Energy Sources (RESs), CPESs are required to provide flexible operation (e.g., load-following, frequency regulation) to respond to any sudden imbalance of the power grid, due to the variability in power generation by RESs. This raises concerns on the reliability of CPESs traditionally used as base-load facilities, such as Nuclear Power Plants (NPPs), which were not designed for flexible operation, and more so, since traditionally only hardware components aging and stochastic failures have been considered for the reliability assessment, whereas the contribution of the degradation and aging of the cyber components of CPSs has been neglected. In this paper, we propose a multi-state model that integrates the hardware components stochastic failures with the aging of cyber components, and quantify the unreliability of CPES in load-following operations under normal/emergency conditions. To show the application of the reliability assessment model, we consider the case of the Control Rod System (CRS) of a NPP typically used for a base-load energy supply.

2021 ◽  
Vol 58 (3) ◽  
pp. 47-65
Author(s):  
L. Petrichenko ◽  
R. Petrichenko ◽  
A. Sauhats ◽  
K. Baltputnis ◽  
Z. Broka

Abstract The electricity sector in Europe and in the world is undergoing rapid and profound changes. There is a sharp increase in the capacity of renewable energy sources, coal and nuclear power plants are being closed and new technologies are being introduced. Especially rapid changes are taking place in the energy systems of the Baltic States. Under these conditions, there is an emerging need for new planning tools particularly for the analysis of the power system properties in a long-term perspective. The main contribution of this article lies in the formulation and solution of optimization problems that arise when planning the development of power systems in the Baltic States. To solve this problem, it is necessary to use models of various power plants and make a number of assumptions, the justification of which requires the following actions: to briefly review the current situation of the production and demand of energy in the Baltic power systems; to conduct an overview of the Baltic interconnections and their development; to make forecasts of energy prices, water inflow, energy production and demand; to set and solve the problems of optimization of power plant operation modes; to demonstrate the possibility and limitations of the developed tools on the basis of real-life and forecast data. In this paper, a case study is performed using the main components of the overall modelling framework being developed. It focuses on the Baltic power systems in 2050 under the conditions of significant expansion in the installed capacity of renewable energy sources (RESs) and diminished fossil fuel power plant activity. The resulting electricity generation mix and trade balance with neighbouring countries is assessed, showing that even with significant RES expansion, the Baltic countries remain net importers and because of the intermittency of RESs, there are hours within the year when the demand cannot be met.


2021 ◽  
Vol 264 ◽  
pp. 04083
Author(s):  
Abror Kurbanov ◽  
Mansur Khasanov ◽  
Anvar Suyarov ◽  
Urinboy Jalilov ◽  
Bakhodir Narimonov ◽  
...  

The use of renewable energy sources (RES) by many power grids companies around the world has increased significantly in recent years. The trend towards the use of RES is mainly due to ecological problems and rising fuel prices related to conventional power generation. Wind power is an approved source for power generation among renewable sources that makes a positive contribution to the global, social and economic environment. Today, wind turbine generator (WTG) is a mature, abundant, and eco-friendly power generation technology, and much of the electricity demand is supplied by wind. However, the uncertain nature of wind speed poses a variety of challenges for the planning and operation of power systems. One of the problems in increasing wind power can be seen in terms of assessment of power system reliability. This paper presents a reliability assessment model of power generation systems (PGS), including WTG, by using an analytical method. The presented model in this paper applied to the Roy Billinton Test System (RBTS). The methodology and results presented in this paper are intended to provide useful information to planners or developers seeking to assess the reliability of PGSs, including WTG.


Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5368
Author(s):  
Ramakrishna S. S. Nuvvula ◽  
Devaraj Elangovan ◽  
Kishore Srinivasa Teegala ◽  
Rajvikram Madurai Elavarasan ◽  
Md. Rabiul Islam ◽  
...  

Higher penetration of variable renewable energy sources into the grid brings down the plant load factor of thermal power plants. However, during sudden changes in load, the thermal power plants support the grid, though at higher ramping rates and with inefficient operation. Hence, further renewable additions must be backed by battery energy storage systems to limit the ramping rate of a thermal power plant and to avoid deploying diesel generators. In this paper, battery-integrated renewable energy systems that include floating solar, bifacial rooftop, and wind energy systems are evaluated for a designated smart city in India to reduce ramping support by a thermal power plant. Two variants of adaptive-local-attractor-based quantum-behaved particle swarm optimization (ALA-QPSO) are applied for optimal sizing of battery-integrated and hybrid renewable energy sources to minimize the levelized cost of energy (LCoE), battery life cycle loss (LCL), and loss of power supply probability (LPSP). The obtained results are then compared with four variants of differential evolution. The results show that out of 427 MW of the energy potential, an optimal set of hybrid renewable energy sources containing 274 MW of rooftop PV, 99 MW of floating PV, and 60 MW of wind energy systems supported by 131 MWh of batteries results in an LPSP of 0.005%, an LCoE of 0.077 USD/kW, and an LCL of 0.0087. A sensitivity analysis of the results obtained through ALA-QPSO is performed to assess the impact of damage to batteries and unplanned load appreciation, and it is found that the optimal set results in more energy sustainability.


Author(s):  
Ye Cheng ◽  
Wang Minglu ◽  
Qiu Zhongming ◽  
Wang Yong

Nuclear power plants are used extensively as base load sources of electricity. This is the most economical and technically simple mode of operation. In this mode, power changes are limited to frequency regulation for grid stability purposes and shutdowns for safety purposes. However for countries with high nuclear shares or desiring to significantly increase renewable energy sources, the question arises as to the ability of nuclear power plants to follow load on a regular basis, including daily variations of the power demand. This paper give a detailed analysis of the technical and economic aspects of load-following with nuclear power plants, and summaries the impact of load-following on the operational mode.


Author(s):  
Giorgio Locatelli ◽  
Andrea Fiordaliso ◽  
Sara Boarin ◽  
Marco Ricotti

Nuclear Power Plants (NPPs) has been historically deployed to cover the base-load of the electric power demand. Nowadays this scenario is changing and some NPPs are requested to perform daily load cycling operation (i.e. load following) between 50% and 100% of their rated power. The traditional methods to perform the load following are by inserting negative or positive reactivity into the core, moving the control rods. This strategy reduces the produced thermal power and in turn the electric power output with respect to the base-load strategy. From a technical standpoint this strategy submits the primary circuit to thermodynamic transients, which causes thermomechanical stresses on some components. From an economic standpoint this operation is very inefficient since, in NPPs, costs are mainly fixed and sunk, and there is a negligible cost saving (if any) in reducing the power of the reactor. A more efficient alternative might be doing the “Load Following by Cogeneration”, i.e. performing the Load Following by diverting the excess of power to an Auxiliary Plant. This paper assesses the technical feasibility of the coupling between a NPP and hypothetical cogenerate plants producing: diesel-like fuels from plastic pyrolysis, or desalinated water, or pellets from waste wood, or hydrogen from water splitting.


Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6587
Author(s):  
Ioannis Avagianos ◽  
Dimitrios Rakopoulos ◽  
Sotirios Karellas ◽  
Emmanouil Kakaras

Since the widespread deployment of non-dispatchable, intermittent, and highly variable power production from renewable energy sources (RES), the demand for flexible power production has been steadily growing. As new-built dispatchable power plants have not been very quickly adapted to the emerging flexible operation, this task has been addressed by existing plants as well. Existing solid-fuel thermal power plants have undergone an extensive study to increase their flexible operation. Thermodynamic process-modeling tools have been extensively used for plant modeling. Steady- and transient-state simulations have been performed under various operating regimes, supplying valuable results for efficient power-plant operation. Flexibility aspects regarding low-load operation and steady operational conditions are mostly investigated with steady-state simulations. Flexibility aspects related to variation over time such as ramping rates are investigated with transient simulations. The off-design operation is mainly attributed to the existing fleet of power plants, struggling to balance between their former operational schemes as base and/or medium-load plants. However, off-design operation is also considered for new plants in the design phase and is included as a simulation aspect. Process modeling turns out to be a proven tool for calculating plant flexibility and predicting extreme operating conditions, defining further steps for a new operational scheme, drafting accident mitigation control procedures or, furthermore, provisioning more complex and cross-field future tasks. A review of the off-design aspect as a simulation approach is undertaken and presented in this work. Finally, challenges and future perspectives for this aspect of solid-fuel thermal power plants are discussed.


Mathematics ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 868 ◽  
Author(s):  
Rebecca Kim ◽  
Yifan Wang ◽  
Sai Pushpitha Vudata ◽  
Debangsu Bhattacharyya ◽  
Fernando V. Lima ◽  
...  

With the increasing penetration of intermittent renewable energy sources into the grid, there is a growing need for process systems-based strategies that integrate dispatchable and variable energy systems for supplying the demand while maintaining grid reliability. The proposed framework corresponds to a dynamic mixed-integer linear programming optimization approach that integrates coal-fired and natural gas-fired power plants, NaS batteries for energy storage, and solar/wind energy to supply the demand. This optimization approach considers an economic goal and constraints to provide power balance while maintaining the overall damage of the natural gas combined cycle (NGCC) power plant drum under a maximum stress as well as avoiding the overheating of the NGCC superheater and reheater. Renewable curtailment levels are also retained at minimum levels. Case studies are analyzed considering different loads and renewable penetration levels. The results show that the demand was met for all cases. Grid flexibility was mostly provided by the NGCC, while the batteries were used sparingly. In addition, considering a CO2 equivalent analysis, the environmental performance was intrinsically connected to grid flexibility and the level of renewable penetration. Stress analysis results reinforced the necessity for an equipment health-related constraint.


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