Pub Date : 2024-12-04DOI: 10.35833/MPCE.2024.000136
Weihua Zhou;Mohammad Hasan Ravanji;Nabil Mohammed;Behrooz Bahrani
The maximum power transfer capability (MPTC) of phase-locked loop (PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control loops. This paper reveals and compares the mechanisms of these violations across different control strategies. Using admittance decomposition and full-order state-space models for eigenvalue analysis, MPTC limitations from control loops and their interactions are identified. The small-signal stabilities of different control loops are compared under varying grid strength, and both static and dynamic MPTCs for each control mode are examined. This paper also explores how control loop interactions impact the MPTC, offering insights for tuning control loops to enhance stability in weak grids. For example, fast power control improves the MPTC when paired with a slow PLL, while power control has minimal effect when the PLL is sufficiently fast. The findings are validated through frequency scanning, eigenvalue analysis, simulations, and experiments.
{"title":"Effects of Control Loop Interactions on Maximum Power Transfer Capability of Weak-Grid-Tied Grid-Following Inverters","authors":"Weihua Zhou;Mohammad Hasan Ravanji;Nabil Mohammed;Behrooz Bahrani","doi":"10.35833/MPCE.2024.000136","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000136","url":null,"abstract":"The maximum power transfer capability (MPTC) of phase-locked loop (PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control loops. This paper reveals and compares the mechanisms of these violations across different control strategies. Using admittance decomposition and full-order state-space models for eigenvalue analysis, MPTC limitations from control loops and their interactions are identified. The small-signal stabilities of different control loops are compared under varying grid strength, and both static and dynamic MPTCs for each control mode are examined. This paper also explores how control loop interactions impact the MPTC, offering insights for tuning control loops to enhance stability in weak grids. For example, fast power control improves the MPTC when paired with a slow PLL, while power control has minimal effect when the PLL is sufficiently fast. The findings are validated through frequency scanning, eigenvalue analysis, simulations, and experiments.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 3","pages":"1078-1089"},"PeriodicalIF":5.7,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10778170","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-04DOI: 10.35833/MPCE.2024.000448
Xiaoping Gao;Guobing Song;Xiaoning Kang;Can Cui;Jifei Yan
Multiterminal low-frequency transmission system (LFTS) has promising potential for large-scale offshore wind power integration. Nevertheless, the existing protection suffers from low sensitivity, and even operates incorrectly because the converters connected to both ends of cables change fault characteristics substantially. To address this problem, this paper firstly inspects the adaptability of current differential protection, revealing the manner in which control strategies after fault impact the sensitivity of the existing protection. Then, based on the characteristics of armored three-core cable, phase-mode transformation is utilized to decouple the fault information and the specific moduli are selected to reflect all kinds of fault types. The expression of backward traveling-wave (BTW) voltage based on interpolation is derived under the condition of low sampling frequency. Finally, a pilot protection based on BTW voltage difference for submarine cables of LFTS with integrated offshore wind power is proposed, which has higher sensitivity because the difference between BTW calculated from local information and the one from remote information is considerable during fault transient period. Simulation tests compare the performance of the existing protection with that of the proposed protection. Extensive simulations corroborate that the proposed protection reliably identifies the fault cable in various fault scenarios.
{"title":"Pilot Protection Based on Backward Traveling-Wave Voltage Difference for Submarine Cables of Low-Frequency Transmission System with Integrated Offshore Wind Power","authors":"Xiaoping Gao;Guobing Song;Xiaoning Kang;Can Cui;Jifei Yan","doi":"10.35833/MPCE.2024.000448","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000448","url":null,"abstract":"Multiterminal low-frequency transmission system (LFTS) has promising potential for large-scale offshore wind power integration. Nevertheless, the existing protection suffers from low sensitivity, and even operates incorrectly because the converters connected to both ends of cables change fault characteristics substantially. To address this problem, this paper firstly inspects the adaptability of current differential protection, revealing the manner in which control strategies after fault impact the sensitivity of the existing protection. Then, based on the characteristics of armored three-core cable, phase-mode transformation is utilized to decouple the fault information and the specific moduli are selected to reflect all kinds of fault types. The expression of backward traveling-wave (BTW) voltage based on interpolation is derived under the condition of low sampling frequency. Finally, a pilot protection based on BTW voltage difference for submarine cables of LFTS with integrated offshore wind power is proposed, which has higher sensitivity because the difference between BTW calculated from local information and the one from remote information is considerable during fault transient period. Simulation tests compare the performance of the existing protection with that of the proposed protection. Extensive simulations corroborate that the proposed protection reliably identifies the fault cable in various fault scenarios.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 4","pages":"1176-1187"},"PeriodicalIF":5.7,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10778169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-28DOI: 10.35833/MPCE.2024.000415
Yi Liu;Xiao Xu;Chuanjiang Deng;Junyong Liu;Lixiong Xu;Youbo Liu;Nan Yang;Yichen Luo;Shafqat Jawad
Rural electrification is a crucial component of the power system that requires urgent innovation and transformation to enhance electrification levels. However, various challenges hinder the progress in rural electrification, primarily due to remote locations and unique consumption patterns. To effectively coordinate the local energy distribution, an energy management framework utilizing peer-to-peer (P2P) based interactive operations is proposed, which minimizes the reliance on long-distance transmission while enhancing the rural electrification level. The proposed P2P-based energy management framework incorporates various distributed generation resources across rural areas, facilitating direct energy transactions between neighboring community-based villages. Additionally, the P2P energy trading is modeled as a Nash bargaining (NB) problem, which accounts for the allocation of network loss costs and operational state of the rural distribution network. To protect the privacy of individual villages, an improved adaptive alternating direction method of multipliers (AADMM) is proposed to solve the NB problem. The AADMM utilizes a local curvature approximation scheme during parameter updates, allowing for automatic adjustments of the fixed penalty parameter within the standard alternating direction method of multipliers (ADMM). This enhancement improves the convergence rates without requiring central oversight. Simulation results demonstrate significant reductions in operational costs for both the overall network and individual village participants. The proposed P2P-based energy management framework also enhances the bus voltage stability and reduces the line transmission power, thereby further enhancing rural electrification levels. The adaptability and extensibility of this framework are further validated using the IEEE 33-bus and 118-bus distribution systems. Additionally, the AAD-MM shows higher convergence rates compared with the standardADMM.
{"title":"Peer-to-Peer Based Energy Management Framework for Enhancing Rural Electrification Level","authors":"Yi Liu;Xiao Xu;Chuanjiang Deng;Junyong Liu;Lixiong Xu;Youbo Liu;Nan Yang;Yichen Luo;Shafqat Jawad","doi":"10.35833/MPCE.2024.000415","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000415","url":null,"abstract":"Rural electrification is a crucial component of the power system that requires urgent innovation and transformation to enhance electrification levels. However, various challenges hinder the progress in rural electrification, primarily due to remote locations and unique consumption patterns. To effectively coordinate the local energy distribution, an energy management framework utilizing peer-to-peer (P2P) based interactive operations is proposed, which minimizes the reliance on long-distance transmission while enhancing the rural electrification level. The proposed P2P-based energy management framework incorporates various distributed generation resources across rural areas, facilitating direct energy transactions between neighboring community-based villages. Additionally, the P2P energy trading is modeled as a Nash bargaining (NB) problem, which accounts for the allocation of network loss costs and operational state of the rural distribution network. To protect the privacy of individual villages, an improved adaptive alternating direction method of multipliers (AADMM) is proposed to solve the NB problem. The AADMM utilizes a local curvature approximation scheme during parameter updates, allowing for automatic adjustments of the fixed penalty parameter within the standard alternating direction method of multipliers (ADMM). This enhancement improves the convergence rates without requiring central oversight. Simulation results demonstrate significant reductions in operational costs for both the overall network and individual village participants. The proposed P2P-based energy management framework also enhances the bus voltage stability and reduces the line transmission power, thereby further enhancing rural electrification levels. The adaptability and extensibility of this framework are further validated using the IEEE 33-bus and 118-bus distribution systems. Additionally, the AAD-MM shows higher convergence rates compared with the standardADMM.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 3","pages":"953-966"},"PeriodicalIF":5.7,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10771626","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-28DOI: 10.35833/MPCE.2024.000416
Hongbin Lin;Pingjuan Ge;Hailiang Xu;Yuhan Duan
Currently, the dominant trend in new energy power supply systems is the heterogeneous inverters-paralleled system (HIPS), which is a combination of grid-following (GFL) and grid-forming (GFM) inverters. The dynamic characteristics of different inverters in HIPS and the differences between GFL and GFM inverters undoubtedly increase the difficulty of the stability analysis and coordinated control. This paper establishes an interactive admittance matrix model of HIPS, fully considers the interactive effects among different inverters, and explores the multi-dimensional resonance characteristics of HIPS by utilizing the modal analysis method. To achieve the coordi-nated control and oscillation suppression among different inverters, a frequency-divided compensation strategy is proposed, which divides the operation modes of HIPS into three catego-ries, i. e., GFM, GFL, and hybrid modes. Specifically, the frequency division boundary is determined based on the resonance characteristics of GFL and GFM inverters, with the operation modes of HIPS being dynamically adjusted according to the harmonic power ratio. Finally, the simulation and experimental results demonstrate that the HIPS can flexibly adjust the operation modes to adapt to the complex conditions after adopting the frequency-divided compensation strategy and suppressing the oscillation frequency ratio to less than 2%, ensuring the safe and reliable operation of HIPS.
{"title":"Resonance Characterization and Frequency-Divided Compensation Strategy for Heterogeneous Inverters-Paralleled System","authors":"Hongbin Lin;Pingjuan Ge;Hailiang Xu;Yuhan Duan","doi":"10.35833/MPCE.2024.000416","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000416","url":null,"abstract":"Currently, the dominant trend in new energy power supply systems is the heterogeneous inverters-paralleled system (HIPS), which is a combination of grid-following (GFL) and grid-forming (GFM) inverters. The dynamic characteristics of different inverters in HIPS and the differences between GFL and GFM inverters undoubtedly increase the difficulty of the stability analysis and coordinated control. This paper establishes an interactive admittance matrix model of HIPS, fully considers the interactive effects among different inverters, and explores the multi-dimensional resonance characteristics of HIPS by utilizing the modal analysis method. To achieve the coordi-nated control and oscillation suppression among different inverters, a frequency-divided compensation strategy is proposed, which divides the operation modes of HIPS into three catego-ries, i. e., GFM, GFL, and hybrid modes. Specifically, the frequency division boundary is determined based on the resonance characteristics of GFL and GFM inverters, with the operation modes of HIPS being dynamically adjusted according to the harmonic power ratio. Finally, the simulation and experimental results demonstrate that the HIPS can flexibly adjust the operation modes to adapt to the complex conditions after adopting the frequency-divided compensation strategy and suppressing the oscillation frequency ratio to less than 2%, ensuring the safe and reliable operation of HIPS.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 1","pages":"42-54"},"PeriodicalIF":5.7,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10771625","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143184158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-27DOI: 10.35833/MPCE.2024.000636
Menghan Zhang;Zhifang Yang;Juan Yu;Wenyuan Li
Maintaining a continuous power balance is crucial for ensuring operational feasibility in power systems. However, due to forecasting difficulties and computational limitations, economic dispatch often relies on discrete interval horizons, which fail to guarantee feasibility within each interval. This paper introduces the concept of a continuous operating envelope for managing intra-interval fluctuations, delineating the range within which fluctuations remain manageable. We propose a parametric programming model to construct the envelope, represented as a polytope that accounts for both timescale and fluctuation dimensions. To address the computational challenges inherent in the parametric programming model, we develop a fast solution method to provide an approximated polytope. The approximated polytope, initially derived from lower-dimensional projections, represents a subset of the exact polytope that ensures operational feasibility. Additionally, we apply a polytope expansion strategy in the original dimensions to refine the approximated polytope, bringing the approximation closer to the exact polytope. Case studies on an illustrative 5-bus and a utility-scale 661-bus system demonstrate that the method effectively and stably provides a continuous operating envelope, particularly for high-dimensional problems.
{"title":"A Continuous Operating Envelope for Managing Intra-Interval Fluctuations: Modeling and Solution","authors":"Menghan Zhang;Zhifang Yang;Juan Yu;Wenyuan Li","doi":"10.35833/MPCE.2024.000636","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000636","url":null,"abstract":"Maintaining a continuous power balance is crucial for ensuring operational feasibility in power systems. However, due to forecasting difficulties and computational limitations, economic dispatch often relies on discrete interval horizons, which fail to guarantee feasibility within each interval. This paper introduces the concept of a continuous operating envelope for managing intra-interval fluctuations, delineating the range within which fluctuations remain manageable. We propose a parametric programming model to construct the envelope, represented as a polytope that accounts for both timescale and fluctuation dimensions. To address the computational challenges inherent in the parametric programming model, we develop a fast solution method to provide an approximated polytope. The approximated polytope, initially derived from lower-dimensional projections, represents a subset of the exact polytope that ensures operational feasibility. Additionally, we apply a polytope expansion strategy in the original dimensions to refine the approximated polytope, bringing the approximation closer to the exact polytope. Case studies on an illustrative 5-bus and a utility-scale 661-bus system demonstrate that the method effectively and stably provides a continuous operating envelope, particularly for high-dimensional problems.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 2","pages":"426-438"},"PeriodicalIF":5.7,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10770094","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-27DOI: 10.35833/MPCE.2024.000390
Xun Jiang;Meiqin Mao;Liuchen Chang;Bao Xie;Haijiao Wang;Nikos D. Hatziargyriou
The oscillatory stability analysis of multi-converter-fed systems (MCFSs) with modest computational resources needs a precise parametric reduced-order impedance model (PROIM). However, the traditional Krylov subspace based parametric model order reduction (KS-PMOR) method has difficulty in building precise PROIM for MCFSs. This is because the factors related to the errors of PROIM are complicated and coupled. To fill this gap, the factors associated with the accuracy of the KS-PMOR method are estimated by defining three indicators: the convergence error, cumulative error, and rank of projection matrix. Using the three indicators, a frequency-domain adaptive parametric model order reduction (FDA-PMOR) method is developed to form the precise PROIM of MCFSs for the accurate and fast oscillatory stability analysis. The accuracy of the obtained PROIM using the proposed FDA-PMOR method and its efficiency in actual oscillatory stability analysis are validated by three MCFSs with different scales, i. e., a small-scale MCFS with four paralleled converter-based renewable energy generators (CREGs), a real-time simulation-based MCFS with eighteen paralleled CREGs, and a larger MCFS with ninety paralleled CREGs.
{"title":"Frequency-Domain Adaptive Parametric Model Order Reduction Method for Oscillatory Stability Analysis on Multi-Converter-Fed Systems","authors":"Xun Jiang;Meiqin Mao;Liuchen Chang;Bao Xie;Haijiao Wang;Nikos D. Hatziargyriou","doi":"10.35833/MPCE.2024.000390","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000390","url":null,"abstract":"The oscillatory stability analysis of multi-converter-fed systems (MCFSs) with modest computational resources needs a precise parametric reduced-order impedance model (PROIM). However, the traditional Krylov subspace based parametric model order reduction (KS-PMOR) method has difficulty in building precise PROIM for MCFSs. This is because the factors related to the errors of PROIM are complicated and coupled. To fill this gap, the factors associated with the accuracy of the KS-PMOR method are estimated by defining three indicators: the convergence error, cumulative error, and rank of projection matrix. Using the three indicators, a frequency-domain adaptive parametric model order reduction (FDA-PMOR) method is developed to form the precise PROIM of MCFSs for the accurate and fast oscillatory stability analysis. The accuracy of the obtained PROIM using the proposed FDA-PMOR method and its efficiency in actual oscillatory stability analysis are validated by three MCFSs with different scales, i. e., a small-scale MCFS with four paralleled converter-based renewable energy generators (CREGs), a real-time simulation-based MCFS with eighteen paralleled CREGs, and a larger MCFS with ninety paralleled CREGs.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 3","pages":"802-814"},"PeriodicalIF":5.7,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10770089","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-27DOI: 10.35833/MPCE.2024.000747
Minghao Guo;Hongjun Gao;Haifeng Qiu;Junyong Liu
As power systems scale up and uncertainties deepen, traditional centralized optimization approaches impose significant computation burdens on large-scale optimization problems, introducing new challenges for power system scheduling. To address these challenges, this study formulates a distributionally robust optimization (DRO) scheduling model that considers source-load uncertainty and is solved using a novel distributed approach that considers the distribution of tie-line endpoints. The proposed model includes a constraint related to the transmission interface, which consists of several tie-lines between two subsystems and is specifically designed to ensure technical operation security. In addition, we find that tie-line endpoints enhance the speed of distributed computation, leading to the development of a power system partitioning approach that considers the distribution of these endpoints. Further, this study proposes a distributed approach that employs an integrated algorithm of column-and-constraint generation (C&CG) and subgradient descent (IACS) to address the proposed model across multiple subsystems. A case study of two IEEE test systems and a practical provincial power system demonstrates that the proposed model effectively ensures system security. Finally, the scalability and effectiveness of the distributed approach in accelerating problem-solving are confirmed.
{"title":"A Distributionally Robust Optimization Scheduling Considering Distribution of Tie-Line Endpoints","authors":"Minghao Guo;Hongjun Gao;Haifeng Qiu;Junyong Liu","doi":"10.35833/MPCE.2024.000747","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000747","url":null,"abstract":"As power systems scale up and uncertainties deepen, traditional centralized optimization approaches impose significant computation burdens on large-scale optimization problems, introducing new challenges for power system scheduling. To address these challenges, this study formulates a distributionally robust optimization (DRO) scheduling model that considers source-load uncertainty and is solved using a novel distributed approach that considers the distribution of tie-line endpoints. The proposed model includes a constraint related to the transmission interface, which consists of several tie-lines between two subsystems and is specifically designed to ensure technical operation security. In addition, we find that tie-line endpoints enhance the speed of distributed computation, leading to the development of a power system partitioning approach that considers the distribution of these endpoints. Further, this study proposes a distributed approach that employs an integrated algorithm of column-and-constraint generation (C&CG) and subgradient descent (IACS) to address the proposed model across multiple subsystems. A case study of two IEEE test systems and a practical provincial power system demonstrates that the proposed model effectively ensures system security. Finally, the scalability and effectiveness of the distributed approach in accelerating problem-solving are confirmed.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 5","pages":"1714-1725"},"PeriodicalIF":6.1,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10770090","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145089990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-27DOI: 10.35833/MPCE.2023.000842
Ni Liu;Hong Wang;Weihua Zhou;Jie Song;Yiting Zhang;Eduardo Prieto-Araujo;Zhe Chen
With the increase of the renewable energy generator capacity, the requirements of the power system for grid-connected converters are evolve, which leads to diverse control schemes and increased complexity of systematic stability analysis. Although various frequency-domain models are developed to identify oscillation causes, the discrepancies between them are rarely studied. This study aims to clarify these discrepancies and provide circuit insights for stability analysis by using different frequency-domain models. This study emphasizes the limitations of assuming that the transfer function of the self-stable converter does not have right half-plane (RHP) poles. To ensure that the self-stable converters are represented by a frequency-domain model without RHP poles, the applicability of this model of grid-following (GFL) and grid-forming (GFM) converters is discussed. This study recommends that the GFM converters with ideal sources should be represented in parallel with the $P/Q-theta/V$ admittance model rather than the V-I impedance model. Two cases are conducted to illustrate the rationality of the $P/Q-theta/V$ admittance model. Additionally, a hybrid frequency-domain modeling framework and stability criteria are proposed for the power system with several GFL and GFM converters. The stability criteria eliminates the need to check the RHP pole numbers in the non-passive subsystem when applying the Nyquist stability criterion, thereby reducing the complexity of stability analysis. Simulations are carried out to validate the correctness of the frequency-domain model and the stability criteria.
{"title":"Hybrid Frequency-domain Modeling and Stability Analysis for Power Systems with Grid-following and Grid-forming Converters","authors":"Ni Liu;Hong Wang;Weihua Zhou;Jie Song;Yiting Zhang;Eduardo Prieto-Araujo;Zhe Chen","doi":"10.35833/MPCE.2023.000842","DOIUrl":"https://doi.org/10.35833/MPCE.2023.000842","url":null,"abstract":"With the increase of the renewable energy generator capacity, the requirements of the power system for grid-connected converters are evolve, which leads to diverse control schemes and increased complexity of systematic stability analysis. Although various frequency-domain models are developed to identify oscillation causes, the discrepancies between them are rarely studied. This study aims to clarify these discrepancies and provide circuit insights for stability analysis by using different frequency-domain models. This study emphasizes the limitations of assuming that the transfer function of the self-stable converter does not have right half-plane (RHP) poles. To ensure that the self-stable converters are represented by a frequency-domain model without RHP poles, the applicability of this model of grid-following (GFL) and grid-forming (GFM) converters is discussed. This study recommends that the GFM converters with ideal sources should be represented in parallel with the <tex>$P/Q-theta/V$</tex> admittance model rather than the V-I impedance model. Two cases are conducted to illustrate the rationality of the <tex>$P/Q-theta/V$</tex> admittance model. Additionally, a hybrid frequency-domain modeling framework and stability criteria are proposed for the power system with several GFL and GFM converters. The stability criteria eliminates the need to check the RHP pole numbers in the non-passive subsystem when applying the Nyquist stability criterion, thereby reducing the complexity of stability analysis. Simulations are carried out to validate the correctness of the frequency-domain model and the stability criteria.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 1","pages":"15-28"},"PeriodicalIF":5.7,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10770097","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143183967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-27DOI: 10.35833/MPCE.2024.000630
Linguang Wang;Xiaorong Xie;Wenkai Dong;Yong Mei;Aoyu Lei
With the rapid integration of renewable energy, wide-band oscillations caused by interactions between power electronic equipment and grids have emerged as one of the most critical stability issues. Existing methods are usually studied for local power systems with around one hundred nodes. However, for a large-scale power system with tens of thousands of nodes, the dimension of transfer function matrix or the order of characteristic equation is much higher. In this case, the existing methods such as eigenvalue analysis method and impedance-based method have difficulty in computation and are thus hard to utilize in practice. To fill this gap, this paper proposes a novel method named the smallest eigenvalues based logarithmic derivative (SELD) method. It obtains the dominant oscillation modes by the logarithmic derivative of the $k$-smallest eigenvalue curves of the sparse extended nodal admittance matrix (NAM). An oscillatory stability analysis tool is further developed based on this method. The effectiveness of the method and the tool is validated through a local power system as well as a large-scale power system.
{"title":"Smallest Eigenvalues Based Logarithmic Derivative Method for Computing Dominant Oscillation Modes in Large-Scale Power Systems","authors":"Linguang Wang;Xiaorong Xie;Wenkai Dong;Yong Mei;Aoyu Lei","doi":"10.35833/MPCE.2024.000630","DOIUrl":"https://doi.org/10.35833/MPCE.2024.000630","url":null,"abstract":"With the rapid integration of renewable energy, wide-band oscillations caused by interactions between power electronic equipment and grids have emerged as one of the most critical stability issues. Existing methods are usually studied for local power systems with around one hundred nodes. However, for a large-scale power system with tens of thousands of nodes, the dimension of transfer function matrix or the order of characteristic equation is much higher. In this case, the existing methods such as eigenvalue analysis method and impedance-based method have difficulty in computation and are thus hard to utilize in practice. To fill this gap, this paper proposes a novel method named the smallest eigenvalues based logarithmic derivative (SELD) method. It obtains the dominant oscillation modes by the logarithmic derivative of the <tex>$k$</tex>-smallest eigenvalue curves of the sparse extended nodal admittance matrix (NAM). An oscillatory stability analysis tool is further developed based on this method. The effectiveness of the method and the tool is validated through a local power system as well as a large-scale power system.","PeriodicalId":51326,"journal":{"name":"Journal of Modern Power Systems and Clean Energy","volume":"13 3","pages":"747-756"},"PeriodicalIF":5.7,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10770088","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-27DOI: 10.35833/MPCE.2024.000563
Sheng Chen;Hao Cheng;Si Lv;Zhinong Wei;Peiyue Li;Jiahui Jin
The gradual replacement of gasoline vehicles with electric vehicles (EVs) and hydrogen fuel cell vehicles (HFCVs) in recent years has provided a growing incentive for the collaborative optimization of power distribution network (PDN), urban transportation network (UTN), and hydrogen distribution network (HDN). However, an appropriate collaborative optimization framework that addresses the prevalent privacy concerns has yet to be developed, and a sufficient pool of system operators that can competently operate all three networks has yet to be obtained. This study proposes a differentiated taxation-subsidy mechanism for UTNs, utilizing congestion tolls and subsidies to guide the independent traffic flow of EVs and HFCVs. An integrated optimization model for this power-hydrogen-transportation network is established by treating these vehicles and the electrolysis equipment as coupling bridges. We then develop a learning-aided decoupling approach to determine the values of the coupling variables acting among the three networks to ensure the economic feasibility of collaborative optimization. This approach effectively decouples the network, allowing it to operate and be optimized independently. The results for a numerical simulation of a coupled system composed of a IEEE 33-node power network, 13-node Nguyen-Dupuis transportation network, and 20-node HDN demonstrate that the proposed learning-aided approach provides nearly equivalent dispatching results as those derived from direct solution of the physical models of the coupled system, while significantly improving the computational efficiency.
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