scholarly journals Generalized Proportional Model of Relay Protection Based on Adaptive Homotopy Algorithm Transient Stability

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 899 ◽  
Author(s):  
Feng Zheng ◽  
Jiahao Lin ◽  
Jie Huang ◽  
Yanzhen Lin
Keyword(s):  
Power Systems ◽  
Transient Stability ◽  
Relay Protection ◽  
Information Value ◽  
Normal Operation ◽  
Stable Operation ◽  
Operation Condition ◽  
Homotopy Algorithm ◽  
Newton Homotopy ◽  
Monitoring Information

Relay protection equipment is important to ensure the safe and stable operation of power systems. The risks should be evaluated, which are caused by the failure of relay protection. At present, the fault data and the fault status monitoring information are used to evaluate the failure risks of relay protection. However, there is a lack of attention to the information value of monitoring information in the normal operation condition. In order to comprehensively improve monitoring information accuracy and reduce, a generalized proportional hazard model (GPHM) is established to fully exploit the whole monitoring condition information during the whole operation process, not just the monitoring fault condition data, with the maximum likelihood estimation (MLE) used to estimate the parameters of the GPHM. For solving the nonlinear equation in the process of parameter estimations, the adaptive homotopy algorithm is adopted, which could ensure the reversibility of the Jacobi matrix. Three testing cases have been reviewed, to demonstrate that the adaptive homotopy algorithm is better than traditional algorithms, such as the Newton homotopy algorithm, regarding the calculation speed and convergence. Therefore, GPHM could not only reflect the real time state of the equipment, but also provide a sound theoretical basis for the selection of equipment maintenance types.

Application of Extreme Learning Machine in Transient Stability Assessment of Power Systems

2013 ◽  
Vol 392 ◽  
pp. 544-547 ◽  
Author(s):  
Yang Li ◽  
Xue Ping Gu
Keyword(s):  
Power Systems ◽  
Extreme Learning Machine ◽  
Rough Sets ◽  
Transient Stability ◽  
Test System ◽  
System Level ◽  
Stability Assessment ◽  
Fuzzy Rough Sets ◽  
Operation Condition ◽  
Learning Machine

This paper presents a new method for transient stability assessment (TSA) of power systems using kernel fuzzy rough sets and extreme learning machine (ELM). Considering the possible real-time information provided by phasor measurement units, a group of system-level classification features were firstly extracted from the power system operation condition to construct the original feature set. Then kernelized fuzzy rough sets were used to reduce the dimension of input space, and ELM was employed to build a TSA model. The effectiveness of the proposed method is validated by the simulation results on the New England 39-bus test system.

scholarly journals Equal-area criterion in power systems revisited

2018 ◽  
Vol 474 (2210) ◽  
pp. 20170733
Author(s):  
Yong Sun ◽  
Jinpeng Ma ◽  
Jürgen Kurths ◽  
Meng Zhan
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transient Stability ◽  
System Analysis ◽  
Stable Operation ◽  
Equal Area ◽  
Power System Analysis ◽  
Stability Behaviour ◽  
Single Machine Infinite Bus ◽  
Machine Systems

The classic equal-area criterion (EAC) is of key importance in power system analysis, and provides a powerful, pictorial and quantitative means of analysing transient stability (i.e. the system's ability to maintain stable operation when subjected to a large disturbance). Based on the traditional EAC, it is common sense in engineering that there is a critical cleaning time (CCT); namely, a power system is stable (unstable) if a fault is cleared before (after) this CCT. We regard this form of CCT as bipartite. In this paper, we revisit the EAC theory and, surprisingly, find different kinds of transient stability behaviour. Based on these analyses, we discover that the bipartite CCT is only one type among four major types, and, actually, the forms of CCT can be diversified. In particular, under some circumstances, a system may have no CCT or show a periodic CCT. Our theoretical analysis is verified by numerical simulations in a single-machine-infinite-bus system and also in multi-machine systems. Thus, our study provides a panoramic framework for diverse transient stability behaviour in power systems and also may have a significant impact on applications of multi-stability in various other systems, such as neuroscience, climatology or photonics.

Anti-Jamming Modification of Exciting System in 600MW Generating Unit

2013 ◽  
Vol 303-306 ◽  
pp. 1291-1296
Author(s):  
Zeng Ji Chen ◽  
Wei Min Fang ◽  
Cong Rong Guan
Keyword(s):  
Electromagnetic Interference ◽  
Transient Stability ◽  
Reactive Power ◽  
Current Control ◽  
Full Duplex ◽  
Control Mode ◽  
Control Voltage ◽  
Stable Operation ◽  
Operation Condition ◽  
Excitation System

In order to reduce excitation system swing and resultant reactive power swing, namely, reduce external electromagnetic interference to stable operation of 600MW generating unit, the paper analyses unit excitation control mode and designs hardware and software of excitation system. First, digital microcomputer control system organization was designed based on nonlinear control theory, which had an increase of control mode such as PID control mode, nonlinear optimum electronic control (NOEC) mode besides original voltage difference and current control mode. Second, full duplex collocation configuration mode of excitation system was designed, namely two controllers were master-slave concurrent, and each controller could meet excitation requirement of various operation condition including constrained excitation. Finally, in electric network disturbance test, measured excitation system parameters recovered stably in 1020 ms such as stator voltage Ut, rotor voltage Uf, comprehensive amplified control voltage Uc, active power P and reactive power Q. It is verified that transient stability and unit operating condition are improved.

scholarly journals Transient Stability Improvement of the Power Systems

2018 ◽  
Vol 12 (3) ◽  
pp. 916
Author(s):  
Zaid H. Al-Tameemi ◽  
Hayder H. Enawi ◽  
Karrar M. Al-Anbary ◽  
Hussam M. Almukhtar
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Transient Stability ◽  
Electrical Power ◽  
Limiting Factor ◽  
Stable Operation ◽  
Electric Power Networks ◽  
Matlab Package ◽  
The Stability

<p>During the last few decades, electrical power demand enlarged significantly whereas power production and transmission expansions has been brutally restricted as a result of restricted resources as well as ecological constrains. Consequently, many transmission lines have been profoundly loading so the stability of power system became as Limiting factor for transferring electrical power. So, maintaining a secure and stable operation of the electric power networks is deemed an imporatant and challenge issue.transient stability of a power system has been gained a considerable attention from researchers dute to it importance . Therefore,this paper sheds light on A substantial number of the adopted techniques, including an inclease in  inertia constant of generator, shunt capacitor, reduction reactance of the transmission line to acheive this purpose. A 7-Machine CIGRE system has been considered a case study. Matlab package has been employed to implement this study. The simulation results show that the transient stability of the repective system enhanced considerably with these techniques.</p>

scholarly journals Enhancement of Transient Stability Limit and Voltage Regulation with Dynamic Loads Using Robust Excitation Control

2013 ◽  
Vol 14 (6) ◽  
pp. 561-570 ◽  
Author(s):  
Jahangir Hossain ◽  
Apel Mahmud ◽  
Naruttam K. Roy ◽  
Hemanshu R. Pota
Keyword(s):  
Power Systems ◽  
High Performance ◽  
Transient Stability ◽  
Stability Limit ◽  
Voltage Regulation ◽  
Test System ◽  
Stable Operation ◽  
Machine Component ◽  
Linear Quadratic ◽  
Robust Controller

Abstract In stressed power systems with large induction machine component, there exist undamped electromechanical modes and unstable monotonic voltage modes. This article proposes a sequential design of an excitation controller and a power system stabiliser (PSS) to stabilise the system. The operating region, with induction machines in stressed power systems, is often not captured using a linearisation around an operating point, and to alleviate this situation a robust controller is designed which guarantees stable operation in a large region of operation. A minimax linear quadratic Gaussian design is used for the design of the supplementary control to automatic voltage regulators, and a classical PSS structure is used to damp electromechanical oscillations. The novelty of this work is in proposing a method to capture the unmodelled nonlinear dynamics as uncertainty in the design of the robust controller. Tight bounds on the uncertainty are obtained using this method which enables high-performance controllers. An IEEE benchmark test system has been used to demonstrate the performance of the designed controller.

scholarly journals A Critical Review of Data-Driven Transient Stability Assessment of Power Systems: Principles, Prospects and Challenges

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7238
Author(s):  
Shitu Zhang ◽  
Zhixun Zhu ◽  
Yang Li
Keyword(s):  
Power Systems ◽  
Transient Stability ◽  
Direct Method ◽  
Data Driven ◽  
Future Research ◽  
Stable Operation ◽  
Stability Assessment ◽  
Renewable Power ◽  
Feature Extraction And Selection ◽  
Actual Operation

Transient stability assessment (TSA) has always been a fundamental means for ensuring the secure and stable operation of power systems. Due to the integration of new elements such as power electronics, electric vehicles and renewable power generations, dynamic characteristics of power systems are becoming more and more complex, which makes TSA an increasingly urgent task. Since traditional time-domain simulations and direct method cannot meet the actual operation requirements of power systems, data-driven TSA has attracted growing attention from both academia and industry. This paper makes a comprehensive review from the following four aspects: feature extraction and selection, model construction, online learning and rule extraction; and then, summarizes the challenges and prospects for future research; finally, draws the conclusions of this review. This review will be beneficial for relevant researchers to better understand the research status, key technologies, and existing challenges in the field.

Overview of Subsynchronous Oscillation in Grid-connected Wind Farm

2020 ◽  
Vol 13 (7) ◽  
pp. 969-979
Author(s):  
Xu Pei-Zhen ◽  
Lu Yong-Geng ◽  
Cao Xi-Min
Keyword(s):  
Power Systems ◽  
Wind Turbine ◽  
Large Scale ◽  
Wind Farm ◽  
Wind Farms ◽  
Induction Generator ◽  
Future Research ◽  
Stable Operation ◽  
Subsynchronous Oscillation ◽  
Different Types

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.

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