Dominated Power System Research Articles

Voltage stability index: a review based on analytical method, formulation and comparison in renewable dominated power system

In an interconnected complex power system network voltage stability evaluation is indispensable to guarantee secure power system operation. To further increase the system performance and to make the system safer assessment, the voltage stability improvement is obligatory. In the various literature different voltage security assessment method using the voltage stability index has been presented. Different lists proposed in literature can be utilized to realize the weak buses and weak transmission lines to enacting the countermeasures against issues of voltage insecurity. Additionally, the arrangement and measuring of inexhaustible assets, on the web and disconnected observing of force framework and the measure of load to be shed at whatever point essential. This paper shows a survey on the different voltage stability index from various perspectives. The audit results on various record gives a far and wide logical to perceive the impending works in this field and to choose the best index for variety of applications such as voltage security assessment, renewable energy integration, distributed generation (DG) placement and sizing, online monitoring of the power system, and shedding of load.

A computational efficient approach for distributionally robust unit commitment with enhanced disjointed layered ambiguity set

AbstractTo achieve the sustainable development of the society, renewable energy dominated power systems are gradually formed. However, the uncertainty of renewable power poses challenges for power system operations, such as balancing the load and generation in day‐ahead unit commitment problems. To address this issue, an enhanced disjointed layered ambiguity set is proposed in this paper to effectively capture the uncertainty of renewable generation forecast errors. On this basis, a two‐stage distributionally robust unit commitment optimization problem is formulated, which is computational challenge. To this end, a novel reformation approach and a worst‐case support set identification method are proposed to derive the optimal solution in a computationally efficient way. Simulation results demonstrate that the proposed ambiguity set brings lower operation costs of unit commitment while maintaining similar reliability compared to existing methods. In detail, the proposed ambiguity set achieves a reduction in operating costs of approximately 10.01%. The proposed novel reformation approach and solution method are also shown to have higher computation efficiency than the existing Benders decomposition method, resulting in a reduction in computation time to less than 3.78% of the original duration.

Technical and economic study of renewable-energy-powered system for a newly constructed city in China

The power and transportation sectors are major carbon emission sources of cities in China, meanwhile, urbanization and industrialization remain the most important impetus for the Chinese economy. Thus, urban-level carbon mitigation is critical for China to realize a low carbon development strategy. This study designs two renewable-energy power-generation dominated power systems for a totally newly built Chinese city, Xiongan, considering emerging technologies, such as vehicle-to-grid as an energy storage facility and geothermal as a local renewable energy resource. The new energy systems are assessed from both economic and carbon emission aspects based on short &long terms power load forecasts. The simulation results shows that the optimal short-term system is a photovoltaic (PV)/geothermal generator/grid purchase/100 Li battery/converter. For the short term, the system's net present cost (NPC) is approximately $8.26B, and the average cost of valuable electrical energy (COE) produced by the system is approximately $0.0942/kWh. The optimal long-term system is a PV/geothermal generator /V2G/ converter, the NPC of the optimal system is approximately $47.7B, and the COE of the system is approximately $0.078/kWh. Energy bill and carbon emissions can both be cut sharply for the city if it adopts these new types of renewable energy dominated systems.

Call for Papers: Special Section on Grid-Forming Converter Dominated Power Systems

Call for Papers: Special Section on Grid-Forming Converter Dominated Power Systems

Design of Hybrid Power Filters for Supraharmonics Suppression in Power Electronics Dominated Power Systems

Design of Hybrid Power Filters for Supraharmonics Suppression in Power Electronics Dominated Power Systems

Subsidizing Grid-Based Electrolytic Hydrogen Will Increase Greenhouse Gas Emissions in Coal Dominated Power Systems.

Clean hydrogen has the potential to serve as an energy carrier and feedstock in decarbonizing energy systems, especially in "hard-to-abate" sectors. Although many countries have implemented policies to promote electrolytic hydrogen development, the impact of these measures on costs of production and greenhouse gas emissions remains unclear. Our study conducts an integrated analysis of provincial levelized costs and life cycle greenhouse gas emissions for all hydrogen production types in China. We find that subsidies are critical to accelerate low carbon electrolytic hydrogen development. Subsidies on renewable-based hydrogen provide cost-effective carbon dioxide equivalent (CO2e) emission reductions. However, subsidies on grid-based hydrogen increase CO2e emissions even compared with coal-based hydrogen because grid electricity in China still relies heavily on coal power and likely will beyond 2030. In fact, CO2e emissions from grid-based hydrogen may increase further if China continues to approve new coal power plants. The levelized costs of renewable energy-based electrolytic hydrogen vary among provinces. Transporting renewable-based hydrogen through pipelines from low- to high-cost production regions reduces the national average levelized cost of renewables-based hydrogen but may increase the risk of hydrogen leakage and the resulting indirect warming effects. Our findings emphasize that policy and economic support for nonfossil electrolytic hydrogen is critical to avoid an increase in CO2e emissions as hydrogen use rises during a clean energy transition.

Decentralized Composite Control for Enhanced Power and Voltage Regulation in Grid-Forming VSC Dominated Power System

Decentralized Composite Control for Enhanced Power and Voltage Regulation in Grid-Forming VSC Dominated Power System

Assessment of grid electricity systems using the life-cycle carbon-emission model

The previous study developed a life-cycle carbon emissions (LCCE) algorithm in MS Excel. Despite improvements, a comprehensive approach is needed to conduct life-cycle carbon emissions inventory (LCCEI) analysis using current methods. This study diverges from existing research by assessing LCCEI data of power generation and transmission systems on studied grids, considering component lifespans, recycling pollutants, and retirement rates. The life-cycle carbon emissions inventory analysis results improve understanding of power system environmental performance, aligning with stakeholders’ objectives. This study aims to enhance the environmental performance of electric power systems in Kenya, Rwanda, and Tanzania by evaluating the LCCE of power generation and transmission within their national grids. The selected grids are the right participants for the study, of non-renewable and renewable grid electricity generation mixes, due to their different environmental features, potential power trade, upcoming grid interconnection, and power transmission practices at various scales. The study applied a life cycle assessment method and simulated the learning patterns using RStudio. The data (emission factors and activity) has been collected from the reports (scientific and technical) and national utility actors. The presented results show that only Kenyan generation and transmission systems have a lifetime decarbonization performance relationship between renewable energy sources dominated power systems and non-renewable energy sources dominated power systems. A major challenge of this study has been the scarcity of primary data, leading to reliance on some secondary and external sources. Therefore, future research should consider the use of more internal and primary data sources, and the use of the most current data, including new technologies adopted from cradle-to-grave of the systems. This study’s findings inform better system designs, policies, and plans for improved environmental performance in electrical power systems.

Survey of Real-World Grid Incidents–Opportunities, Arising Challenges and Lessons Learned for the Future Converter Dominated Power System

Survey of Real-World Grid Incidents–Opportunities, Arising Challenges and Lessons Learned for the Future Converter Dominated Power System

Rapid Decarbonization Roadmap for India Based on Photovoltaic Systems

According to the Paris Agreement signed by national leaders, the rapid decarbonization roadmap is critical for many citizens worldwide. The burden of saving the climate at acceptable levels urges national energy planning activities accordingly. Currently, India has a fossil fuel dominated power system with a rapid increase in renewable energy installations, namely photovoltaic, in the amount of 10 GW per year. India aims to reach 500 GW of installed electricity capacity from non-fossil fuel sources by 2030. This is a very ambitious target, which would require appropriate planning studies for judicious integration and optimal management of the system. Using Energy PLAN (advanced energy system analysis computer model), the authors created various scenarios involving the integration of the above-mentioned renewable energy based capacities into India’s power system. It will provide key insights into the effects of certain policies and scenarios on the future overall energy balance, as well as the environmental (namely CO2 emissions) and social impact, thus enabling more effective policymaking in this key dimension.

Impedance-Based Stability Analysis: Nodal Admittance or Bus Admittance?

Impedance-based stability analysis is widely adopted for small-signal stability demonstration of power electronics dominated power systems. Stability assessment can be performed using either nodal admittance or bus admittance (i.e. equivalent admittance of a network viewed from a specific bus). This paper demonstrates that stability analysis using the bus admittance may not always produce correct results, even though it is easier to implement. Unstable multi-bus systems can be wrongly identified as stable by the single-bus analysis, in the cases where other buses play a dominant role in causing instabilities. A detailed comparison between nodal and bus admittance stability analysis is presented, leading to recommendations for their practical use. A phase-based method is proposed to facilitate the acquisition of eigenloci encirclement around the critical point, which can be used in the stability analysis based on either nodal or bus admittance. Following the conclusion of our work, we recommend multi-bus analysis in white-box model applications for instability mode analysis and stability-oriented design. Single-bus analysis is preferable in black-box model applications due to its simplicity. It is also suggested to select a bus for analysis from those connected to a high share of inverter-based resources, to ensure the correctness of results.

Computing the Demand Response in a Renewable Dominated Power System

Computing the Demand Response in a Renewable Dominated Power System

Preserving Existence of Equilibrium Point for Renewable Energy Source Dominated Power System

Preserving Existence of Equilibrium Point for Renewable Energy Source Dominated Power System

Analysis of the impact of transient overvoltage on grid-connected PMSG-based wind turbine systems

The annual increase in installation capacity and electrical production of renewable energy sources, primarily wind turbine generators (WTG), is shaping a renewable energy dominated power system. WTGs are susceptible to the temporary overvoltage caused by reactive power surplus following low-voltage ride through (LVRT). This can lead to the large-scale trip-off of WTGs and pose significant risks to the secure and stable operation of power systems. An insightful elaboration of the underlying mechanisms determining the occurrence of temporary overvoltage, and an analysis of influencing factors, is pivotal to ensure the reliable integration of WTGs. This paper investigates the temporary overvoltage in the AC systems integrated with multiple renewable energy stations. A temporary overvoltage model that accounts for various types of equipment has been derived. Resorting to the model, the influence of LVRT parameters of WTGs, SCR and IR of the AC system on the maximum terminal overvoltage has been quantitatively assessed. Simulations and semi-physical validations have been conducted to verify the effectiveness and accuracy of the theoretical analysis.

Review on measurement-based frequency dynamics monitoring and analyzing in renewable energy dominated power systems

The massive integration of clean energy and renewable energy source (RES) is one of the most important trends in the low carbon energy transition toward carbon neutrality. Such an important goal significantly alters the power system dynamic behavior. Consequently, monitoring and analyzing the complex frequency dynamic of RES-dominated power systems play an essential role in ensuring power system security and stability. The measurements, especially those supported by wide area measurement systems (WAMSs), can enable full state awareness and deep informatization of the power system and therefore provide effective solutions for monitoring and analyzing system frequency dynamic behaviors with complex features. This paper focus on the application of measurements in monitoring and modeling analysis technologies for the features of frequency dynamics of RES-dominated power systems. We summarize related research on online monitoring of frequency dynamic behavior features based on the information from measurements. Further, for system frequency security assessment, measurements can improve the traditional methods and promote new data-driven methods for more accuracy and effective frequency dynamics analysis. Finally, future directions and possible solutions for measurement-based frequency dynamics monitoring and analyzing are prospected.

Plausibility and Implications of Converter-Driven Oscillations Induced by Unstable Long-Term Dynamics

For decades, synchronous generators have dominated power system dynamics and have been the foundation for the comprehension of the physical phenomena involved in power system stability. This paradigm is rapidly changing; large synchronous generators that contribute to system strength are being replaced by inverter-based generators. Consequently, new kinds of instabilities are emerging. Slow-interaction converter-driven instability is one example in which undamped oscillations occur when inverter-based generators operate in weak areas. Transmission system operators have observed the phenomenon under the scope of short-term dynamics following a disturbance during a weak operating condition. This paper suggests that converter-driven oscillations can occur even in the case when the system's initial operating condition is strong. It concludes that the phenomenon can be triggered by long-term dynamics that slowly weaken the system in which small-signal and short-term simulations show an ample stability margin. The outcome is a combination of unstable long-term dynamics and undamped oscillations. Furthermore, this work suggests that classical emergency controllers that are effective against long-term instability may not be successful if undamped oscillations are also present. A method for instability detection and counteraction is proposed based on Prony analysis and time-domain simulations on the IEEE test system for voltage stability assessment.

Optimal capacitor planning for power factor improvement using hybrid particle swarm and harmony search optimization

Industrial loads reduce the Power Factor (PF) of supply systems, causing increases in power losses, damaging equipment and higher utility bills. Optimization techniques are used in planning reactive sources to improve PF of power systems. However, conventional techniques suffer difficulties in passing over local optimal, divergence risk, constraints handling or computing higher order derivatives. Herein, the hybridization of Particle Swarm and Harmony Search Algorithm (PS – HSA) is developed for optimal capacitor planning to improve PF, and comparison is made with the Enhanced Particle Swarm Optimization (EPSO) and Improved Adaptive Harmony Search Algorithm (IAHSA). The test systems are the Modified IEEE 6 and 16 buses and nodes respectively. To create semblance of industrial load dominated power systems, the test networks were modified by increasing the reactive load demand at all buses of the IEEE 6 and 16 by 50% and 70% respectively. The capacitor is modelled as static shunt-controlled element deployed to inject reactive power at buses/nodes. Results show that for IEEE 6 buses, PF improved from 0.68 to 0.8983, 0.8986 and 0.8992 with EPSO, IAHSA and hybrid PS – HSA respectively. Similarly, in IEEE 16 nodes, PF improved from 0.76 to 0.9439, 0.943, and 0.944 with EPSO, IAHSA and hybrid PS – HSA respectively. Furthermore, real power losses reduced from 16.94 MW to 14.03 MW in IEEE 6 buses, translating to 17.2% reduction with the hybrid PS - HSA. While in IEEE 16 nodes, reduction is from 0.719 MW to 0.69 MW accounting for 4% reduction, also with the hybrid PS - HSA.

Transient Stability Assessment of Renewable Dominated Power Systems by the Method of Hyperplanes

With continuous increase of penetration of renewable energies and power electronic equipment, power grid stability incidents are emerging frequently worldwide. In this paper, the transient stability assessment of renewable dominated power systems with multiple PLL-based voltage source converters (VSCs) is studied by calculating critical clearing time (CCT). A tangent hyperplane method is developed, which approximates the boundary of basin of attraction near unstable equilibrium point by linear system theory. The detailed algorithm is presented, accompanying with four typical case studies, including a single machine infinite system, two parallel VSCs, modified IEEE 9- bus, and modified 39- bus systems. Broad EMT simulations are performed to verify the accuracy and computational effectiveness of the algorithm. In all these tests, we find that the hyperplane method can give accurate estimations of CCTs. Hence it is expected to be an efficient method. In addition, we find that generally the CCT in renewable dominated power systems is around tens of milliseconds, which is much shorter than that in traditional power systems around hundreds of milliseconds. Therefore, it might be imperative to adopt faster controls and protections for renewable dominated power systems.

Female Subjugation and Resistance in Jean Rhys's Wide Sargasso Sea

Jean Rhys's Portrays the European domination and patriarchal cultural context of Jamaica after the passage of the Emancipation Act (1833). The novelist stages creole characters who are exclusively exploited, subjugated and marginalized in colonial regime. In this respect, the representations of the female characters such as Antoinette, Christophine, Gracepoole, Amelie, Leah, among others clearly display the debased status of females in Jamaica even after the emancipatory proclamation. The novel dramatizes the violence perpetrated on women by the White colonizers even after the colonial rule. Moreover, Rhys projects female characters to expose the humiliating state of women in the novel. Thus, this article proposes to analyze the female body as a subordinated site as well as resistance in the purview of postcolonial feminist theory especially of Gyatri Spivak, Ketu Katrak and Chandra D. Mohanty address the challenges faced by subjugated and marginalized voices in representing themselves within dominant discourses. So, the research draws on the ideas of Spivak’s “Can the subaltern speak?” as the subaltern refers to individuals or groups who are socially, politically, racially, culturally and economically subjugated and silenced by dominant power structure and system. Their feminist stands unbox the exploitation of female and their feeble resistance in the commonwealth countries that this research critically analyzes Rhys’s novel. Imbibing their arguments it further, argues that Wide Sargasso Sea not only revisits the lacuna prevalent in colonial historiography by depicting the colonized people but also clearly points out the marginal representation of female under the ambit of imperial power.

Representing Online Hostility against Women

Representing Online Hostility against Women