Available transfer capability (ATC) is defined as a measure of the system's capability for transfers of power for further commercial activity, over and above already committed uses. In practical power markets, ATC...
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A new self-shunt excitation control method has been brought in this paper, which is about how to use DC chopper that is composed with full controlled switch device IGBT to regulate exciting voltage. This new method re...
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A new self-shunt excitation control method has been brought in this paper, which is about how to use DC chopper that is composed with full controlled switch device IGBT to regulate exciting voltage. This new method replaces traditional method which is adopted controlled rectifier by thyristor. Exciting voltage refers from terminal voltage by exciting transformer, and then it goes through uncontrollable rectifier circuit and switches to DC voltage. This DC voltage is used for DC chopper. We can control duty cycle of IGBT to change output voltage and hold terminal voltage steady. In this paper, the conclusion of DC chopper output current proportioned with duty cycle is proved by simulation in PSCAD. And it also proves that it can maintain terminal voltage stability in steady state operation by the control of trigger angle of IGBT.
Theoretical and simulated analysis on the injection circuit parameters of the controllable Custom power Quality Disturbance-Generator which is designed as differentiation cascade type has been done. The topology has t...
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Theoretical and simulated analysis on the injection circuit parameters of the controllable Custom power Quality Disturbance-Generator which is designed as differentiation cascade type has been done. The topology has three modules: fundamental-frequency module, high-frequency module and rectifier module. The theoretical analysis results have shown that the regulation precision of output of the fundamental-frequency module, the voltage level of the high-frequency module, the current tracking performance and the harmonic current circumfluence in the high frequency module will be influenced by the linking inductor of the fundamental-frequency module. The harmonic current output of the high-frequency module will be influenced by the linking inductor of the high-frequency module. Furthermore, taking a capacitor in series with the inductor in the injection circuit of the high-frequency module is an effective method to reduce the voltage level of the high-frequency module. However, this method will influence the amount of the fundamental frequency current that generated by fundamental-frequency module. The simulations have been carried out to show the correctness of the theoretical analysis and provide a reference for parameters selection of the injection circuit and the design of the device's control methods.
DSR (dynamic security region) is one of the direct methods focusing on the transient stability of powersystem. This paper focuses on the DSRs of powersystem with different load models, and explores the characteristi...
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DSR (dynamic security region) is one of the direct methods focusing on the transient stability of powersystem. This paper focuses on the DSRs of powersystem with different load models, and explores the characteristic of the DSRs of the powersystem with constant impedance load and motor load. It deduces the algorithm for DSR of powersystem described with differential algebraic equation, after introducing the theory of DSR for powersystem with network-reduction model. And then, it presents the mathematical models for the constant impedance load and motor load. Based on the simulation results, it presents the DSRs for the powersystem with respect to constant impedance load and motor load, respectively. And furthermore, it compares the characteristic of the DSRs of powersystem with different loads, and summarizes the impact of different loads characteristic on the DSR.
Three single-phase H-bridge DVR is a kind of dynamic voltage restorer (DVR) which is used very widely. The traditional analysis method of compensation strategy has some shortcomings so that it is not suitable for this...
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Three single-phase H-bridge DVR is a kind of dynamic voltage restorer (DVR) which is used very widely. The traditional analysis method of compensation strategy has some shortcomings so that it is not suitable for this kind of DVR. A new analysis method which could overcome the shortcomings of the tradition method is proposed in the paper. The new method not only has definite physical concept but also could determine the compensation range easily when unbalanced voltage sag happened. More importantly, it could be applied to unbalanced load. Adopting the new method, the compensation strategy of three single-phase H-bridge DVR is studied. The simulation result shows the correctness of the theoretical analysis.
The operational state determination of power equipment is a key prerequisite to realize maintenance. On studying the relationship between power equipment state and its acoustic wave mutation character, a new diagnosis...
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ISBN:
(纸本)9781424463343
The operational state determination of power equipment is a key prerequisite to realize maintenance. On studying the relationship between power equipment state and its acoustic wave mutation character, a new diagnosis scheme of power equipment fault has been put forward. After the running acoustic signal acquired, MFCC coefficient has been selected the acoustic signal various band energy feature, and dynamic time warping (DTW) is utilized to determine equipment type. Then local energy band based wavelet packet decomposition is used in fault feature extraction. According to these feature parameters values and expert experience scoring, the knowledge based of fault database was established to diagnosis power equipment state and its fault level. Lastly, By 200 group transformer measured acoustic signal analysis experiments have been completed, and the results show the series acoustic treatment of methods is effective, and the diagnosis scheme of equipment failures have great practical value.
The electromechanical coupling model is employed to define the all-mode shape and torsional mode shape, and deduce the linear solutions of torques. Based on the solutions of torques, mode shapes of torques and mode co...
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In load model verification process, the accuracy of model and its parameters makes the actual operating conditions unable to reappear in simulation. The information deviation between measured data and verifiable simul...
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In load model verification process, the accuracy of model and its parameters makes the actual operating conditions unable to reappear in simulation. The information deviation between measured data and verifiable simulation data makes it impossible to ensure the descriptive power of measurement-based load model for real load characteristics. With this problem, the paper applies closed-loop verification approach to this question for the first time. The closed-loop verification approach is common in system identification study but newly used in load model comparison and validation. Two cases based on PSASP are studied in the paper. The object of this study is composite load model and the verification is carried out on a 10-generator, 39-bus New England powersystem. They both prove the validity of composite load model and the feasibility of this verification approach.
The removal of overload lines can cause power flow transferring, which may give rise to some transmission lines overload. By analysis of available methods of determining transmission sections with shortcomings, this p...
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The removal of overload lines can cause power flow transferring, which may give rise to some transmission lines overload. By analysis of available methods of determining transmission sections with shortcomings, this paper proposes a new way to determine transmissions section based on real-time power flows, and then deduce a new criterion of transmission section security protection based on the redundancy of normal line's power flows. A new transmission section security protectioncontrol scheme based on wide area measurement system (WAMS) is also proposed. When there is line overload, we should make a decision according to the protection criterion, if the transmission lines are safe after the overload removal, allow the backup protection to cut off the overload line; if not, block the protection. Therefore, it can avoid cascading overload tripping. At last, the validity of proposed algorithm is verified by the simulation results of CEPRI 36-bus system.
When taking emergency control measures to eliminate the overload circuits, it is necessary to ensure the normal lines of powersystem won't overload. Therefore, it's necessary to analyze the security of the no...
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When taking emergency control measures to eliminate the overload circuits, it is necessary to ensure the normal lines of powersystem won't overload. Therefore, it's necessary to analyze the security of the normal lines when take measures to eliminate overload. Based on the analysis of traditional methods of eliminating overload lines, this paper proposes an new overload control scheme based on wide area information, which can in parallel analyzing the impact of the normal line's redundancy on the regulated quantity of matching units, then the analysis results are sent to the control center, which finally determines the regulated quantity. It can ensure the normal lines won't overload when eliminating overload, and also can improve the computing speed of the whole control process. Therefore, it's very conducive to ensure the powersystem operating in a safe and stable state. Finally, simulation experiments verify the program is fast and reasonable.
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