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The dynamic line rating (DLR) is recognized as an effective method to improve the integration of renewable energies, such as wind power by enhancing the flexibility of the system. The principle of DLR is to increase the transmission capacity of a transmission line according to the forecasted weather data. However, the uncertainties of DLR and wind power caused by the forecasting errors might bring in some severe consequences to the power system, such as line overloads. In this paper, we propose a tri-level preventive dispatch model to deal with this issue. To reduce the conservativeness of the solution, we employ the Density-Based Spatial Clustering of Application with Noise (DBSCAN) method to identify and remove the extreme scenarios of DLR. And a decomposition method is proposed to solve the tri-level model.The numerical simulations on several IEEE bus systems demonstrate the effectiveness of the proposed model.
Zongchao Yu; Xuan Liu. A Secure Dispatch Strategy subject to the Uncertainties of DLR and Wind Power. IEEE Transactions on Industrial Informatics 2021, PP, 1 -1.
AMA StyleZongchao Yu, Xuan Liu. A Secure Dispatch Strategy subject to the Uncertainties of DLR and Wind Power. IEEE Transactions on Industrial Informatics. 2021; PP (99):1-1.
Chicago/Turabian StyleZongchao Yu; Xuan Liu. 2021. "A Secure Dispatch Strategy subject to the Uncertainties of DLR and Wind Power." IEEE Transactions on Industrial Informatics PP, no. 99: 1-1.
Cyberattack emerges as a critical concern in Internet-of-Things integrated power systems. Cybersecurity capabilities of power systems rely on a deep understanding of potential cyberattacks for identifying and protecting against cyber vulnerabilities. The common assumption of system network information in most existing works is suspicious, which fails to hold in practical fields. This paper proposes a novel data-driven false data injection attack method, where only easily accessible measurement data are required, i.e., power injections at buses, flows of lines and the tie line information (connection relationship and power measurement data). In the proposed method, generative adversarial network (GAN) is adopted to extract the physical model using historical measurement data, and a self-attention mechanism is integrated to further capture the power flow laws in the data. After offline training, the effective false data can be constructed in a timely fashion without system network information. The effectiveness of the proposed attack method is validated using the IEEE14 and IEEE118 systems, in which the constructed false data injection attack can evade the system residual detection with an average success rate over 90% under different levels of measuring errors.
Runhai Jiao; Gangyi Xun; Xuan Liu; Guangwei Yan. A New AC False Data Injection Attack Method without Network Information. IEEE Transactions on Smart Grid 2021, PP, 1 -1.
AMA StyleRunhai Jiao, Gangyi Xun, Xuan Liu, Guangwei Yan. A New AC False Data Injection Attack Method without Network Information. IEEE Transactions on Smart Grid. 2021; PP (99):1-1.
Chicago/Turabian StyleRunhai Jiao; Gangyi Xun; Xuan Liu; Guangwei Yan. 2021. "A New AC False Data Injection Attack Method without Network Information." IEEE Transactions on Smart Grid PP, no. 99: 1-1.
The penetration of renewable energy generations, e.g., wind power, not only introduces the randomness and fluctuations into power system operations but also increases the possibilities of cybersecurity issues. Among them, false data injection attack (FDIA) can access and falsify the readings of smart meters, which would impede the functionalities of power systems. In this paper, we first set up an evaluation model to identify the set of high-risk lines by investigating the relationship between FDIA and wind power uncertainty. Then, for a power system with a high wind penetration, a tri-level preventive dispatch strategy is proposed to ensure the system security even under the worst-case of FDIA. It is demonstrated that the impacts of FDIA can cause more serious security issues as the wind penetration level increases. The effectiveness of the proposed tri-level preventive dispatch strategy in mitigating the FDIA caused overloading risk is validated using the IEEE 118-bus system.
Kehe Wu; Jiawei Li; Bo Zhang; Zongchao Yu; Xuan Liu. Preventive Dispatch Strategy Against FDIA Induced Overloads in Power Systems With High Wind Penetration. IEEE Access 2020, 8, 210452 -210461.
AMA StyleKehe Wu, Jiawei Li, Bo Zhang, Zongchao Yu, Xuan Liu. Preventive Dispatch Strategy Against FDIA Induced Overloads in Power Systems With High Wind Penetration. IEEE Access. 2020; 8 (99):210452-210461.
Chicago/Turabian StyleKehe Wu; Jiawei Li; Bo Zhang; Zongchao Yu; Xuan Liu. 2020. "Preventive Dispatch Strategy Against FDIA Induced Overloads in Power Systems With High Wind Penetration." IEEE Access 8, no. 99: 210452-210461.
With development of power electronic technology, the paralleled current-controlled voltage source converters (CCSs) and virtual synchronous generators (VSGs) system has advantages in providing power and voltage/frequency regulation at the same time in rural area or remote island. However, the paralleled system faces great challenges in safe and stable operation due to their limited thermal capacity and weak anti-disturbance ability, especially during fault periods. This paper focuses on transient stability and stability-oriented control design of the paralleled CCS-VSG system. First, mathematical model of the paralleled system is established and then the effect of two kinds of CCSs’ current injection angle (active current and reactive current) on VSG’s transient stability has been revealed through extended equal area criterion. Based on the theoretical analysis results, transient stability improvement control is put forward by controlling the CCS to track the VSG’s frame. Compared with the conditions that only active-or reactive current is provided by the CCS, the system can achieve the best transient performance when the proposed control is adopted. Moreover, the effect of CCS’s capacity on transient stability of the VSG has also been discussed. Finally, both Lyapunov’s method and simulation/experimental results are provided to validate the correctness of theoretical analysis.
Chao Shen; Zhikang Shuai; Yang Shen; Yelun Peng; Xuan Liu; Zuyi Li; Z. John Shen. Transient Stability and Current Injection Design of Paralleled Current-Controlled VSCs and Virtual Synchronous Generators. IEEE Transactions on Smart Grid 2020, 12, 1118 -1134.
AMA StyleChao Shen, Zhikang Shuai, Yang Shen, Yelun Peng, Xuan Liu, Zuyi Li, Z. John Shen. Transient Stability and Current Injection Design of Paralleled Current-Controlled VSCs and Virtual Synchronous Generators. IEEE Transactions on Smart Grid. 2020; 12 (2):1118-1134.
Chicago/Turabian StyleChao Shen; Zhikang Shuai; Yang Shen; Yelun Peng; Xuan Liu; Zuyi Li; Z. John Shen. 2020. "Transient Stability and Current Injection Design of Paralleled Current-Controlled VSCs and Virtual Synchronous Generators." IEEE Transactions on Smart Grid 12, no. 2: 1118-1134.
This paper investigates the stability performances of bidirectional ac-dc converters considering operating conditions based on the small-signal impedance model. It finds that the converter has different stability margins when working in different operating conditions (including inverter mode and rectifier mode, as well as generating/absorbing reactive power), which should be taken into account in the design of the converter for bidirectional energy conversions. To have an intuitive understanding of the instability mechanisms of bidirectional converters in different operating conditions, the concept of positive feedback is used. It finds that with phase-lock loop (PLL) and dc-link voltage control loop (VCL), positive feedback effects appear when the converter operating in different conditions; and the influencing mechanisms of the parameters, including control parameters of PLL, inner current and outer voltage controllers and power ratings, on the converter’s stability can be explicitly identified by the positive feedback gains. And it indicates that reducing the values of the parameters along the positive feedback paths will be a practical way to enhance the converter’s stability. The theoretical stability analysis results are verified by simulations and experiments.
Yang Li; Zhikang Shuai; Xuan Liu; Yi Hong; Xiangyang Wu; Z. John Shen. Stability Investigation of Bidirectional AC-DC Converter Considering Operating Conditions. IEEE Access 2020, 8, 131499 -131510.
AMA StyleYang Li, Zhikang Shuai, Xuan Liu, Yi Hong, Xiangyang Wu, Z. John Shen. Stability Investigation of Bidirectional AC-DC Converter Considering Operating Conditions. IEEE Access. 2020; 8 ():131499-131510.
Chicago/Turabian StyleYang Li; Zhikang Shuai; Xuan Liu; Yi Hong; Xiangyang Wu; Z. John Shen. 2020. "Stability Investigation of Bidirectional AC-DC Converter Considering Operating Conditions." IEEE Access 8, no. : 131499-131510.
With the development of virtual synchronous generator (VSG) techniques, parallel operations of synchronous generators (SGs) and VSGs become increasingly common in a microgrid. The differences between paralleled systems will affect transient stability of the system, which probably threatens stable operation of the system, especially under fault conditions. In this paper, transient angle stability of a paralleled synchronous and virtual synchronous generators (SG-VSG) system is investigated by compared with that of paralleled VSGs system. It is observed that the paralleled SG-VSG system is more prone to transient instability due to the differences between their speed governors. Then, a control method is proposed to improve the transient stability of paralleled SG-VSG system. Furthermore, a Lyapunov method is employed to establish the nonlinear model of islanded microgrid, by which the attraction domain of paralleled system is quantified. The hardware-in-loop experiment is performed to validate the theoretical analysis.
Huijie Cheng; Zhikang Shuai; Chao Shen; Xuan Liu; Zuyi Li; Z. John Shen. Transient Angle Stability of Paralleled Synchronous and Virtual Synchronous Generators in Islanded Microgrids. IEEE Transactions on Power Electronics 2020, 35, 8751 -8765.
AMA StyleHuijie Cheng, Zhikang Shuai, Chao Shen, Xuan Liu, Zuyi Li, Z. John Shen. Transient Angle Stability of Paralleled Synchronous and Virtual Synchronous Generators in Islanded Microgrids. IEEE Transactions on Power Electronics. 2020; 35 (8):8751-8765.
Chicago/Turabian StyleHuijie Cheng; Zhikang Shuai; Chao Shen; Xuan Liu; Zuyi Li; Z. John Shen. 2020. "Transient Angle Stability of Paralleled Synchronous and Virtual Synchronous Generators in Islanded Microgrids." IEEE Transactions on Power Electronics 35, no. 8: 8751-8765.
In a cyber-attack, the attacker can impose security impacts by injecting false data into measurements to affect the power system scheduling and dispatch. In real-time, the system is dispatched in successive dispatch intervals. The existing methods analyze the attacks based on a snapshot of the system condition at the end of a dispatch interval, at which the dispatch is achieved. Such analysis falls into a static analysis framework (SAF). However, with the increasing share of intermittent resources, the system is suffering short-term fluctuations which will increase the system vulnerability and render weak points during a dispatch interval. These weak points can be exploited by smart attackers to impose large impacts on the intra-interval operational security. Such cyber risk may be ignored or underestimated by the existing methods under the SAF. To address this risk, this paper analyzes the intra-interval operational security under a dynamic analysis framework (DAF) and quantifies the impacts of potential data attacks on the intra-interval security. Simulations are performed based on the historical wind data on the IEEE 118-bus system, which verify the proposed approach and highlight the risk of such issues in power systems with significant wind penetration.
Xuan Liu; Liang Che; Kunlun Gao; Zuyi Li. Power System Intra-Interval Operational Security Under False Data Injection Attacks. IEEE Transactions on Industrial Informatics 2019, 16, 4997 -5008.
AMA StyleXuan Liu, Liang Che, Kunlun Gao, Zuyi Li. Power System Intra-Interval Operational Security Under False Data Injection Attacks. IEEE Transactions on Industrial Informatics. 2019; 16 (8):4997-5008.
Chicago/Turabian StyleXuan Liu; Liang Che; Kunlun Gao; Zuyi Li. 2019. "Power System Intra-Interval Operational Security Under False Data Injection Attacks." IEEE Transactions on Industrial Informatics 16, no. 8: 4997-5008.
This paper presents an impedance-based method for stability analysis of multi-converter power systems based on the Generalized Nyquist Stability Criterion. The return-ratio matrix of the system is formulated on the basis of the nodal admittance matrix as well as output admittance of the converters, which can be applicable for the large-scale systems with complicated structure. A modified IEEE 13-bus system is used as the testing system, which shows that the proposed method can be easily implemented for location optimization of the converters. And the participation factors of return-ratio matrix’s critical eigenvalues (which encircle the critical point (-1, 0j)) at the instability frequencies are used to identify which converters have significant contributions to the instability, and then guidance for the design of system parameters can be provided. Simulations in PSCAD/EMTDC validate the effectiveness of the proposed stability analysis method.
Yang Li; Zhikang Shuai; Xuan Liu; Yandong Chen; Zuyi Li; Yi Hong; Z. John Shen. Stability Analysis and Location Optimization Method for Multiconverter Power Systems Based on Nodal Admittance Matrix. IEEE Journal of Emerging and Selected Topics in Power Electronics 2019, 9, 529 -538.
AMA StyleYang Li, Zhikang Shuai, Xuan Liu, Yandong Chen, Zuyi Li, Yi Hong, Z. John Shen. Stability Analysis and Location Optimization Method for Multiconverter Power Systems Based on Nodal Admittance Matrix. IEEE Journal of Emerging and Selected Topics in Power Electronics. 2019; 9 (1):529-538.
Chicago/Turabian StyleYang Li; Zhikang Shuai; Xuan Liu; Yandong Chen; Zuyi Li; Yi Hong; Z. John Shen. 2019. "Stability Analysis and Location Optimization Method for Multiconverter Power Systems Based on Nodal Admittance Matrix." IEEE Journal of Emerging and Selected Topics in Power Electronics 9, no. 1: 529-538.
A two-layer optimal consensus-based distributed control strategy is proposed for the coordinated operation of networked microgrids (MGs). Several networked MG operation objectives are optimized using the proposed control strategy, including frequency/voltage regulation, proportional active power sharing, and smooth MG islanding/reconnection operation. The global objective function of networked MGs is decomposed into a series of local objectives assigned to participating distributed energy resources (DERs). In the decomposed optimization, each control layer is realized in a distributed manner in which DER state variables reach consensus along with optimizing their assigned local objective functions. Each control layer in the two-layer control strategy is formulated as an optimal consensus problem in which the optimality and asymptotical stability of the system equilibrium point for each control layer are demonstrated. The effectiveness of the proposed control strategy is validated in a modified IEEE 33-bus distribution system using the PSCAD/EMTDC platform.
Quan Zhou; Zhen Tian; Mohammad Shahidehpour; Xuan Liu; Ahmed AlAbdulwahab; Abdullah M. Abusorrah. Optimal Consensus-Based Distributed Control Strategy for Coordinated Operation of Networked Microgrids. IEEE Transactions on Power Systems 2019, 35, 2452 -2462.
AMA StyleQuan Zhou, Zhen Tian, Mohammad Shahidehpour, Xuan Liu, Ahmed AlAbdulwahab, Abdullah M. Abusorrah. Optimal Consensus-Based Distributed Control Strategy for Coordinated Operation of Networked Microgrids. IEEE Transactions on Power Systems. 2019; 35 (3):2452-2462.
Chicago/Turabian StyleQuan Zhou; Zhen Tian; Mohammad Shahidehpour; Xuan Liu; Ahmed AlAbdulwahab; Abdullah M. Abusorrah. 2019. "Optimal Consensus-Based Distributed Control Strategy for Coordinated Operation of Networked Microgrids." IEEE Transactions on Power Systems 35, no. 3: 2452-2462.
Contingencies occurring in multi-terminal high voltage direct current (MT-HVDC) grids can result in DC voltage/flow violations and also affect the frequency stability of the connected multiple asynchronous grids. To recognize and control such notable operating risks, a novel flexible risk-limiting optimal power flow (FROPF) for the MT-HVDC grid with vast wind generation is proposed in this paper. Within the two-stage FROPF structure, the pre-contingency operation of grid-side voltage-source converters (GVSCs) is optimized to minimize MT-HVDC grid power losses. Immediately following an outage occurring in the MT-HVDC grid, various fast-acting corrective actions of GVSCs are utilized to hedge against the overall risk exposure, including the wind power curtailment risk of the MT-HVDC grid and the rate-of-change-of-frequency (RoCoF) violation risk imposed on associated asynchronous grids. Reformulation techniques are introduced to ease the computational complexity of the optimization model. Case studies of two MT-HVDC grids demonstrate the effectiveness of the proposed FROPF.
Yunfeng Wen; C. Y. Chung; Zhikang Shuai; Liang Che; Youqiang Xiao; Xuan Liu. Toward Flexible Risk-Limiting Operation of Multi-Terminal HVDC Grids With Vast Wind Generation. IEEE Transactions on Sustainable Energy 2019, 11, 1750 -1760.
AMA StyleYunfeng Wen, C. Y. Chung, Zhikang Shuai, Liang Che, Youqiang Xiao, Xuan Liu. Toward Flexible Risk-Limiting Operation of Multi-Terminal HVDC Grids With Vast Wind Generation. IEEE Transactions on Sustainable Energy. 2019; 11 (3):1750-1760.
Chicago/Turabian StyleYunfeng Wen; C. Y. Chung; Zhikang Shuai; Liang Che; Youqiang Xiao; Xuan Liu. 2019. "Toward Flexible Risk-Limiting Operation of Multi-Terminal HVDC Grids With Vast Wind Generation." IEEE Transactions on Sustainable Energy 11, no. 3: 1750-1760.
Microgrids (MGs) operate under harmonic conditions due to the integration of nonlinear loads. The autonomous harmonic compensation control of inverterinterfaced DG has been proposed to successfully mitigate the harmonics. However, the small-signal analysis of harmonic compensation controls has not been investigated in the microgrid with multiple inverters. This paper develops the modeling and analysis of the inverterbased MGs under harmonic conditions. The concept of dynamic phasor (DP) is used to describe the fundamental and harmonic components of an ac waveform via dc variables. The developed model consists of droop-controlled distributed generators (DGs), diodes rectifiers (working as nonlinear load) and resistance loads. Virtual impedance control is considered in the droop-controlled DGs for the autonomous harmonic compensation. Based on the developed DP model, the dynamic behavior of the microgrid is investigated via small-signal analysis. It is observed that the virtual impedance for harmonic compensation brings inter-inverter oscillations on harmonic domain. Participation and eigenlocus analysis are performed to investigate the influence of parameter tuning of harmonic compensation on microgrid stability. Numerical simulations are carried out to validate the effectiveness of the proposed modeling method and the analysis results.
Yelun Peng; Zhikang Shuai; Xuan Liu; Zuyi Li; Josep M. Guerrero; Z. John Shen. Modeling and Stability Analysis of Inverter-Based Microgrid Under Harmonic Conditions. IEEE Transactions on Smart Grid 2019, 11, 1330 -1342.
AMA StyleYelun Peng, Zhikang Shuai, Xuan Liu, Zuyi Li, Josep M. Guerrero, Z. John Shen. Modeling and Stability Analysis of Inverter-Based Microgrid Under Harmonic Conditions. IEEE Transactions on Smart Grid. 2019; 11 (2):1330-1342.
Chicago/Turabian StyleYelun Peng; Zhikang Shuai; Xuan Liu; Zuyi Li; Josep M. Guerrero; Z. John Shen. 2019. "Modeling and Stability Analysis of Inverter-Based Microgrid Under Harmonic Conditions." IEEE Transactions on Smart Grid 11, no. 2: 1330-1342.
The cybersecurity of wind farms is an increasing concern in recent years, and its impacts on the power system reliability have not been fully studied. In this paper, the pressing issues of wind farms, including cybersecurity and wind power ramping events (WPRs) are incorporated into a new reliability evaluation approach. Cyber–physical failures like the instantaneous failure and longtime fatigue of wind turbines are considered in the reliability evaluation. The tripping attack is modeled in a bilevel optimal power flow model which aims to maximize the load shedding on the system’s vulnerable moment. The time-varying failure rate of wind turbine is approximated by Weibull distribution which incorporates the service time and remaining life of wind turbine. Various system defense capacities and penetration rates of wind power are simulated on the typical reliability test system. The comparative and sensitive analyses show that power system reliability is challenged by the cybersecurity of wind farms, especially when the installed capacity of wind power continues to rise. The timely patching of network vulnerabilities and the life management of wind turbines are important measures to ensure the cyber–physical security of wind farms.
Honghao Wu; Junyong Liu; Jichun Liu; Mingjian Cui; Xuan Liu; Hongjun Gao. Power Grid Reliability Evaluation Considering Wind Farm Cyber Security and Ramping Events. Applied Sciences 2019, 9, 3003 .
AMA StyleHonghao Wu, Junyong Liu, Jichun Liu, Mingjian Cui, Xuan Liu, Hongjun Gao. Power Grid Reliability Evaluation Considering Wind Farm Cyber Security and Ramping Events. Applied Sciences. 2019; 9 (15):3003.
Chicago/Turabian StyleHonghao Wu; Junyong Liu; Jichun Liu; Mingjian Cui; Xuan Liu; Hongjun Gao. 2019. "Power Grid Reliability Evaluation Considering Wind Farm Cyber Security and Ramping Events." Applied Sciences 9, no. 15: 3003.
The integration of information and network technologies has significantly boosted the efficiency of electric power delivery, but at the same time poses new cyber threats to a power grid. An attacker can compromise meter readings by injecting false data. It was revealed that such false data is able to escape the traditional bad data detection once it obeys the physical laws of the system. However, in this letter we demonstrate that such false data usually can be treated as an outlier, which can be effectively detected by several anomaly detection methods. Unfortunately, we further demonstrate that such false data can be stealthy through hiding among normal data if it is carefully designed. Such false data is defined as dummy data, whose stealthiness is validated by the simulations on the IEEE 24-bus and IEEE 30-bus systems.
Xuan Liu; Yufei Song; Zuyi Li. Dummy Data Attacks in Power Systems. IEEE Transactions on Smart Grid 2019, 11, 1792 -1795.
AMA StyleXuan Liu, Yufei Song, Zuyi Li. Dummy Data Attacks in Power Systems. IEEE Transactions on Smart Grid. 2019; 11 (2):1792-1795.
Chicago/Turabian StyleXuan Liu; Yufei Song; Zuyi Li. 2019. "Dummy Data Attacks in Power Systems." IEEE Transactions on Smart Grid 11, no. 2: 1792-1795.
This paper studies the parameter stability region of droop-controlled AC microgrid (MG) with static ZIP (constant impedance, constant current, constant power) load and dynamic induction motor (IM) load using bifurcation theory. First, the dynamic model of the MG with ZIP and IM loads is developed. Next, bifurcation analysis is used to predict the bifurcation boundaries where microgrid becomes unstable. Saddle node and hopf bifurcation are detected in the studied system when parameters change. The stability region in parameters space is bounded by bifurcation boundaries. To improve the computing efficiency for predicting the stable region of parameters, the reduced-order models of MGs are developed based on singular perturbation method. Finally, numerical simulations and experiment are used to verify the analysis result and the effectiveness of the proposed strategy.
Zhikang Shuai; Yelun Peng; Xuan Liu; Zuyi Li; Josep M. Guerrero; Z. John Shen. Parameter Stability Region Analysis of Islanded Microgrid Based on Bifurcation Theory. IEEE Transactions on Smart Grid 2019, 10, 6580 -6591.
AMA StyleZhikang Shuai, Yelun Peng, Xuan Liu, Zuyi Li, Josep M. Guerrero, Z. John Shen. Parameter Stability Region Analysis of Islanded Microgrid Based on Bifurcation Theory. IEEE Transactions on Smart Grid. 2019; 10 (6):6580-6591.
Chicago/Turabian StyleZhikang Shuai; Yelun Peng; Xuan Liu; Zuyi Li; Josep M. Guerrero; Z. John Shen. 2019. "Parameter Stability Region Analysis of Islanded Microgrid Based on Bifurcation Theory." IEEE Transactions on Smart Grid 10, no. 6: 6580-6591.
Lili He; Zhikang Shuai; Xin Zhang; Xuan Liu; Zuyi Li; Z. John Shen. Transient Characteristics of Synchronverters Subjected to Asymmetric Faults. IEEE Transactions on Power Delivery 2019, 34, 1171 -1183.
AMA StyleLili He, Zhikang Shuai, Xin Zhang, Xuan Liu, Zuyi Li, Z. John Shen. Transient Characteristics of Synchronverters Subjected to Asymmetric Faults. IEEE Transactions on Power Delivery. 2019; 34 (3):1171-1183.
Chicago/Turabian StyleLili He; Zhikang Shuai; Xin Zhang; Xuan Liu; Zuyi Li; Z. John Shen. 2019. "Transient Characteristics of Synchronverters Subjected to Asymmetric Faults." IEEE Transactions on Power Delivery 34, no. 3: 1171-1183.
This letter describes an enhanced multi-period dispatch model for microgrids, in which frequency-aware islanding constraints are established to ensure microgrids with the capability to ride through unplanned islanding events. Rather than specifying the upward/downward primary reserve requirements as fixed amounts, the proposed dispatch scheme determines the primary reserve requirements by explicitly simulating under- or over-frequency dynamics caused by potential islanding events. To remove the nonlinearity, a two-stage solution strategy is proposed. Case studies demonstrate the effectiveness of the proposed microgrid dispatch scheme.
Yunfeng Wen; C. Y. Chung; Xuan Liu; Liang Che. Microgrid Dispatch With Frequency-Aware Islanding Constraints. IEEE Transactions on Power Systems 2019, 34, 2465 -2468.
AMA StyleYunfeng Wen, C. Y. Chung, Xuan Liu, Liang Che. Microgrid Dispatch With Frequency-Aware Islanding Constraints. IEEE Transactions on Power Systems. 2019; 34 (3):2465-2468.
Chicago/Turabian StyleYunfeng Wen; C. Y. Chung; Xuan Liu; Liang Che. 2019. "Microgrid Dispatch With Frequency-Aware Islanding Constraints." IEEE Transactions on Power Systems 34, no. 3: 2465-2468.
In past studies on cascading failure assessment, the risk of N – x initiating contingencies (ICs) regarding their initiating effect and hidden contingency risk (a high-risk x-component outage sequence within the IC) may not be fully investigated, which may underestimate the risk of IC-triggered cascading overload failures (COFs). In addition, the research on the efficient screening of N – x IC (x ≥ 2) and the identification of the cascading with the largest system impact is limited. To undertake this challenge, this paper proposes a COF identification approach (CIA) which integrates the IC screening and the COF identification for finding the high-impact COFs initiated by N – x ICs with hidden risks. The CIA is validated by simulations on the IEEE 118-bus system. The simulation results demonstrate that the CIA can efficiently screen out the high-risk N – 2 and N – 3 ICs that have an optimal outage sequence and trigger COF chains. The results also show that the CIA can identify the IC-triggered high-impact COFs and quantifies their impacts. The approach can be used as either a cascade-triggering event screening tool (by applying the IC screening module) or a COF risk assessment tool for ensuring system reliability.
Liang Che; Xuan Liu; Yunfeng Wen; Zuyi Li. Identification of Cascading Failure Initiated by Hidden Multiple-Branch Contingency. IEEE Transactions on Reliability 2019, 68, 149 -160.
AMA StyleLiang Che, Xuan Liu, Yunfeng Wen, Zuyi Li. Identification of Cascading Failure Initiated by Hidden Multiple-Branch Contingency. IEEE Transactions on Reliability. 2019; 68 (1):149-160.
Chicago/Turabian StyleLiang Che; Xuan Liu; Yunfeng Wen; Zuyi Li. 2019. "Identification of Cascading Failure Initiated by Hidden Multiple-Branch Contingency." IEEE Transactions on Reliability 68, no. 1: 149-160.
This paper analyzes a malicious data attack in which the attacker targets at the generation side of the system and aims to compromise the system security by causing large power imbalance in the real-time operations. Such an attack is called the ramp-induced data (RID) attack in the literature which revealed that the attacker can manipulate the limits of generator ramp constraints in real-time dispatch (RTD) and, thus, impact the power market operations. In this paper, we propose an optimal attack model to analyze the impact of the RID attack on power system operational security and show that the attacker can introduce large power imbalance into real-time operations that can cause security issues or even catastrophic consequences. To address the risk of such an attack, a countermeasure is presented that reassesses the regulation reserve adequacy against a given risk level of the attack. Simulations on the IEEE 118-bus system verify the impact of the proposed RID attack and the effectiveness of the regulation assessment approach.
Liang Che; Xuan Liu; Zhikang Shuai; Junbo Zhao. The Impact of Ramp-Induced Data Attacks on Power System Operational Security. IEEE Transactions on Industrial Informatics 2019, 15, 5064 -5075.
AMA StyleLiang Che, Xuan Liu, Zhikang Shuai, Junbo Zhao. The Impact of Ramp-Induced Data Attacks on Power System Operational Security. IEEE Transactions on Industrial Informatics. 2019; 15 (9):5064-5075.
Chicago/Turabian StyleLiang Che; Xuan Liu; Zhikang Shuai; Junbo Zhao. 2019. "The Impact of Ramp-Induced Data Attacks on Power System Operational Security." IEEE Transactions on Industrial Informatics 15, no. 9: 5064-5075.
In real-time operations, the forecasts and dispatches are associated with the ending time instants of dispatch intervals, while the wind power variations during the interval are unknown. When a high-wind-penetrated system encounters large short-term wind variations, the intra-interval variations (IIVs) of wind power and generation ramping can lead to unsecured operating conditions inside of an interval, referred to as the intra-interval security (IIS) issue. The goal of this study is to reveal the IIS issue under high wind penetration and analyze its impacts. To this end, this study investigates the nature of the IIS problem based on the dispatch interval mechanism, reveals the nonlinearity of wind IIVs as the root cause of the IIS issues (regulation shortage and transmission overloads), and proposes an assessment tool for assessing such issues. The tool screens the worst-case wind IIVs and assesses the issues using severity indices. The tool also considers the spatial correlation among wind farms and demonstrates that the IIS issues still exist under such correlation. Simulations on the IEEE 118-bus system verify the effectiveness of the proposed tool and highlight the IIS risks in power systems with high wind penetration.
Liang Che; Xuan Liu; Xin Zhu; Mingjian Cui; Zuyi Li. Intra-Interval Security Assessment in Power Systems With High Wind Penetration. IEEE Transactions on Sustainable Energy 2018, 10, 1890 -1903.
AMA StyleLiang Che, Xuan Liu, Xin Zhu, Mingjian Cui, Zuyi Li. Intra-Interval Security Assessment in Power Systems With High Wind Penetration. IEEE Transactions on Sustainable Energy. 2018; 10 (4):1890-1903.
Chicago/Turabian StyleLiang Che; Xuan Liu; Xin Zhu; Mingjian Cui; Zuyi Li. 2018. "Intra-Interval Security Assessment in Power Systems With High Wind Penetration." IEEE Transactions on Sustainable Energy 10, no. 4: 1890-1903.
Cascading failures in power grids are typically triggered by initiating contingencies (ICs). Traditional assumption is that those multiple-component ICs have low chances of occurring. However, considering the increasing cyber events in power grids, this brief reveals that smart attackers can target at critical ICs and implement well-designed cyber attacks to highly increase the ICs' occurrence probabilities by overloading key branches in the grid. This will greatly increase the grid vulnerability to cascading failures. In this brief, such issue is revealed and analyzed using a two-step approach, which consists of a high-probability IC screening and a deterministic cascading testing. The simulation results on the IEEE 118-bus systems verify the effectiveness of the proposed approach and highlight the increased risk imposed by cyber-attacks.
Liang Che; Xuan Liu; Tao Ding; Zuyi Li. Revealing Impacts of Cyber Attacks on Power Grids Vulnerability to Cascading Failures. IEEE Transactions on Circuits and Systems II: Express Briefs 2018, 66, 1058 -1062.
AMA StyleLiang Che, Xuan Liu, Tao Ding, Zuyi Li. Revealing Impacts of Cyber Attacks on Power Grids Vulnerability to Cascading Failures. IEEE Transactions on Circuits and Systems II: Express Briefs. 2018; 66 (6):1058-1062.
Chicago/Turabian StyleLiang Che; Xuan Liu; Tao Ding; Zuyi Li. 2018. "Revealing Impacts of Cyber Attacks on Power Grids Vulnerability to Cascading Failures." IEEE Transactions on Circuits and Systems II: Express Briefs 66, no. 6: 1058-1062.