Applied Sciences

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18 pages, 1439 KiB

Open AccessArticle

Source-Grid Coordinated Planning Considering Network Node Inertia Level Differences Under Coal-Fired Power Unit Retirement

by Yutao Xu, Chao Sun, Lu Liu, Houyi Zhang, Wenxia Liu and Zhukui Tan

Appl. Sci. 2025, 15(3), 1490; https://doi.org/10.3390/app15031490 - 1 Feb 2025

Viewed by 578

Abstract

How to consider the differentiated inertia levels of each node during the retirement of coal-fired power units to ensure system frequency security is a current research challenge. This paper proposes a source-grid collaborative planning method that accounts for the differentiated inertia levels of [...] Read more.

How to consider the differentiated inertia levels of each node during the retirement of coal-fired power units to ensure system frequency security is a current research challenge. This paper proposes a source-grid collaborative planning method that accounts for the differentiated inertia levels of network nodes during the coal-fired power unit retirement. First, a frequency response model based on a multi-machine equivalence approach and a differentiated inertia level model based on a virtual synchronous machine transformation approach for each network node are established, and a node inertia constraint model can be obtained. Next, the characteristics of coal-fired power unit retirement are analyzed. Subsequently, a source-grid collaborative planning model that considers the differentiated inertia levels of network nodes during the retirement of coal-fired power units is proposed. Finally, the feasibility and effectiveness of the coal-fired unit retirement and source-grid planning model are validated by the IEEE 24-node case and a real-region case. The case study analysis indicates that compared with the conventional planning scheme, the planning scheme considering the node inertia level constraints has less retired thermal unit capacity, more installed capacity of new thermal units, and a uniform distribution of inertia levels. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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32 pages, 6854 KiB

Open AccessArticle

Quantifying the Impact and Policy Implications of Transitioning to Zonal and Nodal Pricing in the Electricity Market: A South Korean Case Study

by Kyuhyeong Kwag, Hansol Shin, Hyobin Oh, Hyeongseok Yun, Hyojeong Yoon and Wook Kim

Appl. Sci. 2025, 15(2), 716; https://doi.org/10.3390/app15020716 - 13 Jan 2025

Viewed by 1127

Abstract

Electricity markets are transitioning to zonal and nodal pricing to maximize social welfare, improve price signals, and enhance congestion management. South Korea, traditionally reliant on uniform pricing, is evaluating this transition but lacks a detailed impact analysis. This study assessed the impacts of [...] Read more.

Electricity markets are transitioning to zonal and nodal pricing to maximize social welfare, improve price signals, and enhance congestion management. South Korea, traditionally reliant on uniform pricing, is evaluating this transition but lacks a detailed impact analysis. This study assessed the impacts of various zonal and nodal pricing schemes on power systems and provided policy implications for this transition. We (1) modeled the power system at various levels of granularity, obtaining a detailed 4579-node representation; (2) constructed a set of zonal and nodal pricing schemes reflecting changes in market-clearing models and pricing mechanisms; and (3) performed quantitative analyses through simulations for each scheme. Under the current system marginal price (SMP)-based uniform pricing, the schemes with the least market impact are SMP-based zonal pricing with two bidding zones and extended locational marginal pricing. These results can guide the development of an appropriate pricing transition pathway, although a market price reduction of 4.8–7.0% appears inevitable. Within the Korean electricity market, wherein a Transco is a monopoly retailer, we identified potential conflicts of interest for the Transco in zonal and nodal pricing. By focusing on South Korea, this study offers valuable insights into any electricity market considering the transition to zonal and nodal pricing. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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18 pages, 3189 KiB

Open AccessArticle

Analysis of China’s Low-Carbon Power Transition Path Considering Low-Carbon Energy Technology Innovation

by Peng Xia, Gang Lu, Bo Yuan, Yichun Gong and Haitao Chen

Appl. Sci. 2025, 15(1), 340; https://doi.org/10.3390/app15010340 - 1 Jan 2025

Cited by 1 | Viewed by 978

Abstract

Innovation in key low-carbon technologies plays a supporting role in achieving a high-quality low-carbon transition in the power sector. This paper aims to integrate research on the power transition pathway under the “dual carbon” goals with key technological innovation layouts. First, it deeply [...] Read more.

Innovation in key low-carbon technologies plays a supporting role in achieving a high-quality low-carbon transition in the power sector. This paper aims to integrate research on the power transition pathway under the “dual carbon” goals with key technological innovation layouts. First, it deeply analyzes the development trends of three key low-carbon technologies in the power sector—new energy storage, CCUS, and hydrogen energy—and establishes a quantitative model for their technological support in the low-carbon transition of the power sector. On this basis, the objective function and constraints of traditional power planning models are improved to create an integrated optimization model for the power transition pathway and key low-carbon technologies. Finally, a simulation analysis is conducted using China’s power industry “dual carbon” pathway as a case study. The optimization results include the power generation capacity structure, power generation mix, carbon reduction pathway, and key low-carbon technology development path for China from 2020 to 2060. Additionally, the impact of uncertainties in breakthroughs in new energy storage, CCUS, and hydrogen technologies on the power “dual carbon” pathway is analyzed, providing technological and decision-making support for the low-carbon transition of the power sector. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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26 pages, 7547 KiB

Open AccessArticle

Optimization of Active Distribution Network Operation with SOP Considering Reverse Power Flow

by Zhanhui Ma and Fang Cao

Appl. Sci. 2024, 14(24), 11797; https://doi.org/10.3390/app142411797 - 17 Dec 2024

Viewed by 906

Abstract

As the penetration of distributed renewable energy increases, the phenomenon of bidirectional power flow in distribution networks becomes increasingly severe. Traditional regulation devices like OLTC (on-load tap changer) and CB (capacitor bank) cannot effectively mitigate reverse power flow in distribution networks due to [...] Read more.

As the penetration of distributed renewable energy increases, the phenomenon of bidirectional power flow in distribution networks becomes increasingly severe. Traditional regulation devices like OLTC (on-load tap changer) and CB (capacitor bank) cannot effectively mitigate reverse power flow in distribution networks due to their limitations. The transmission capacity of the distribution network under reverse power flow is approximately 50% of the rated capacity of the OLTC, leading to issues such as voltage limit violations and high wind and solar curtailment rates. This paper proposes a method for calculating the reverse power flow delivery capacity of distribution networks, quantitatively describing the distribution network’s delivery limits for reverse power flow. Based on this, a joint optimization model for multiple distribution networks with an SOP is established. The SOP is utilized to share reverse power flow delivery capacity among multiple distribution networks, enhancing operational economy and increasing the accommodation of the DG. Finally, the method’s effectiveness and correctness are verified in the IEEE 33-node system. The results validate that while joint operation does not enhance the reverse flow transmission capacity of a single distribution network, it can, through the shared reverse flow transmission capacity approach, elevate the reverse flow transmission capacity to approximately 70% during the majority of time periods. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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19 pages, 2454 KiB

Open AccessArticle

Real-Time Optimization of Ancillary Service Allocation in Renewable Energy Microgrids Using Virtual Load

by Amir Abed and Goran Dobric

Appl. Sci. 2024, 14(18), 8370; https://doi.org/10.3390/app14188370 - 18 Sep 2024

Cited by 2 | Viewed by 1341

Abstract

The stability of global economies relies heavily on power systems (PS) that have sufficient operating reserves. When these reserves are insufficient, power systems become vulnerable to issues such as load shedding or complete blackouts. Maintaining grid stability becomes even more challenging with a [...] Read more.

The stability of global economies relies heavily on power systems (PS) that have sufficient operating reserves. When these reserves are insufficient, power systems become vulnerable to issues such as load shedding or complete blackouts. Maintaining grid stability becomes even more challenging with a high penetration of renewable energy sources (RES). However, RES, connected through power electronic devices, offer significant potential as ancillary service (AS) sources. Renewable energy-based microgrids (MG), which aggregate various RES resources and have substantial load control potential, further enhance the capability of AS provision from RES. The presence of diverse AS resources raises the question of how to dispatch ancillary service signals optimally to all resources. Most of the previous research work related to AS allocation relied on single-bus MG models. This paper proposes a detailed MG model for the optimal dispatching of ASs among the resources using Virtual Load, along with an optimization procedure to achieve the best results. The model incorporates voltage profiles and power losses for AS dispatching, and a comparative analysis is conducted to quantify the significance of grid modeling. The model and proposed procedure are tested using the CIGRE microgrid benchmark model. The results indicate that detailed modeling of MG can impact the results by 11%, compared to single-bus modeling, which qualifies detailed MG modeling for all future research work and shows the impact that modeling can have on technical and economic indicators of MG operation. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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22 pages, 4141 KiB

Open AccessArticle

Coordinated Planning of Soft Open Points and Energy Storage Systems to Enhance Flexibility of Distribution Networks

by Jingyu Li, Yifan Zhang, Chao Lv, Guangchen Liu, Zhongtian Ruan and Feiyang Zhang

Appl. Sci. 2024, 14(18), 8309; https://doi.org/10.3390/app14188309 - 14 Sep 2024

Cited by 2 | Viewed by 1147

Abstract

With the large-scale penetration of distributed generation (DG), the volatility problems of active distribution networks (ADNs) have become more prominent, which can no longer be met by traditional regulation means and need to be regulated by introducing flexible resources. Soft open points (SOP) [...] Read more.

With the large-scale penetration of distributed generation (DG), the volatility problems of active distribution networks (ADNs) have become more prominent, which can no longer be met by traditional regulation means and need to be regulated by introducing flexible resources. Soft open points (SOP) and energy storage systems (ESS) can regulate the tidal currents on spatial and temporal scales, respectively, to improve the flexibility of ADN. To this end, in-depth consideration of DG admission is given to establish flexibility assessment indicators from the power side of ADN. The conditional deep convolution generative adversarial network (C-DCGAN) is used to generate the output scenario of DG. On this basis, the SOP and ESS two-layer planning models, which take account of the potential for improvement in the flexibility of ADN, are constructed. Among them, the upper layer is the site selection and volume determination layer, which considers the economy of the system with the optimization objective of minimizing the annual integrated cost; the lower layer is the operation optimization layer, which considers the flexibility of the system and takes the highest average daily flexibility level as the optimization objective. The planning model is solved using genetic algorithm-particle swarm optimization (GA-PSO) and second-order cone programming (SOCP). The case analysis verifies the rationality and effectiveness of the planning model. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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24 pages, 3493 KiB

Open AccessArticle

Synergistic Optimization of Coal Power and Renewable Energy Based on Generalized Adequacy

by Hao Yue, Bingqing Wu, Shunxin Li, Yin Zhang, Jin Gao, Yi Zhou, Zijian Meng and Zhaoyuan Wu

Appl. Sci. 2024, 14(17), 7864; https://doi.org/10.3390/app14177864 - 4 Sep 2024

Cited by 2 | Viewed by 1046

Abstract

As China accelerates its transition to a low-carbon society, its power system is facing growing challenges in terms of maintaining adequacy amid a rapidly evolving energy structure. The concept of adequacy, traditionally focused on power capacity and generation, has broadened to include dimensions [...] Read more.

As China accelerates its transition to a low-carbon society, its power system is facing growing challenges in terms of maintaining adequacy amid a rapidly evolving energy structure. The concept of adequacy, traditionally focused on power capacity and generation, has broadened to include dimensions like flexibility and inertia. Against this backdrop, optimizing the integration of coal power and renewable energy to meet the system’s needs for adequacy, flexibility, and frequency stability has become a critical research area. This paper introduces the concept of “Generalized Adequacy”, expanding the traditional understanding of adequacy, and proposes an optimization model for the coordinated development of coal power and renewable energy based on this concept. This study examines the effects of extreme weather, renewable energy penetration, wind–solar ratios, and generalized adequacy constraints using a case study from a central region of China. The findings reveal that extreme weather conditions drive an increase in photovoltaic installations, while higher renewable energy penetration leads to more wind power installations. Accounting for generalized adequacy constraints can moderate the retirement of coal-fired plants, reducing unnecessary inertia support in normal conditions and ensuring dynamic frequency stability during extreme weather events. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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24 pages, 2897 KiB

Open AccessArticle

Multi-Stage Coordinated Planning for Transmission and Energy Storage Considering Large-Scale Renewable Energy Integration

by Yan Liang, Hongli Liu, Hengyu Zhou, Zijian Meng, Jinxiong Liu and Ming Zhou

Appl. Sci. 2024, 14(15), 6486; https://doi.org/10.3390/app14156486 - 25 Jul 2024

Cited by 5 | Viewed by 1112

Abstract

Due to the large-scale integration of renewable energy and the rapid growth of peak load demand, it is necessary to comprehensively consider the construction of various resources to increase the acceptance capacity of renewable energy and meet power balance conditions. However, traditional grid [...] Read more.

Due to the large-scale integration of renewable energy and the rapid growth of peak load demand, it is necessary to comprehensively consider the construction of various resources to increase the acceptance capacity of renewable energy and meet power balance conditions. However, traditional grid planning methods can only plan transmission lines, often resulting in low utilization rates of newly constructed lines. Additionally, static planning methods can only address single-target scenarios and cannot cope with dynamic growth in load and renewable energy. To address these issues, this paper proposes a multi-stage collaborative planning method for transmission networks and energy storage. This method considers the non-line substitution effect of energy storage resources and their characterization methods. It establishes the coupling relationship between resources across different planning stages to achieve coordinated multi-stage planning for transmission networks and energy storage. Based on the IEEE-24 node system and a case study in a northern province of China, the results show that the proposed method reduces investment costs by approximately 30% compared to static planning methods and by about 7.79% compared to conventional grid planning methods. Furthermore, this method can accommodate more renewable energy. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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16 pages, 2914 KiB

Open AccessArticle

Analyzing the Impact of Volatile Electricity Prices on Solar Energy Capture Rates in Central Europe: A Comparative Study

by Marek Pavlík, Matej Bereš and František Kurimský

Appl. Sci. 2024, 14(15), 6396; https://doi.org/10.3390/app14156396 - 23 Jul 2024

Cited by 1 | Viewed by 1934

Abstract

Electricity prices have been exceptionally volatile in recent years. In 2022, we witnessed a sharp increase in electricity prices in many countries. Several factors contributed to this, including reduced electricity production by hydropower plants due to climatic conditions and geopolitical situations around the [...] Read more.

Electricity prices have been exceptionally volatile in recent years. In 2022, we witnessed a sharp increase in electricity prices in many countries. Several factors contributed to this, including reduced electricity production by hydropower plants due to climatic conditions and geopolitical situations around the world, amongst other factors. The research presented in this paper aims to analyze electricity price data and determine the parameters CPS (Capacity Payment Scheme) and CRS (Capacity Remuneration Scheme). These parameters are calculated from hourly data on a monthly basis from 2018 to the present. Determining these parameters provides a clearer understanding of the efficiency of utilizing photovoltaic power plants. However, the results indicate that identical CRS values can signify different situations in the electricity market. Given the current support for projects utilizing photovoltaic energy, the research findings may offer insights into the future direction of photovoltaic energy utilization. If CRS and CPS show positive trends (e.g., increasing values), this may suggest that current political measures (subsidies, supports, etc.) are effective. Policymakers could then strengthen or expand these measures. The research outcomes could shape the geopolitical situation in individual states. The research results show how differences in electricity prices in 2022 compared to pre-2022 affected CSP and CRS parameters. The findings also indicate that electricity prices vary across different countries, which naturally impacts the calculation of CPS and CRS. In 2024, a significant decline in CRS was observed across all analyzed countries, which may indicate issues with integrating solar energy into the market, market saturation, or changes in market dynamics. Full article

(This article belongs to the Special Issue New Insights into Power Systems)

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