Large scale renewable energy, represented by wind power and photovoltaic power, has brought many problems for the safe and stable operation of power system. Firstly, this paper analyzes the main problems brought by la...
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ISBN:
(数字)9781728156224
ISBN:
(纸本)9781728156231
Large scale renewable energy, represented by wind power and photovoltaic power, has brought many problems for the safe and stable operation of power system. Firstly, this paper analyzes the main problems brought by large-scale wind power and photovoltaic power integration into the power system. Secondly, the paper introduces the basic principle and engineering construction of pumped storage power station. Thirdly, the paper expounds in detail the current application of pumped storage power station in power system, and finally points out the main problems faced by the development of Pumped Storage power Station and the development trend, so as to provide reference for the construction and operation of pumped storage power station.
Continuous-time random disturbances (also called stochastic excitations) due to increasing renewable generation have an increasing impact on power system dynamics;However, except from the Monte Carlo simulation, most ...
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With an increasing penetration of distributed energy resources (DERs) in Energy Internet, there is a surge of interest in distributed economic dispatch (DED) problems. The existing literature mainly focuses on average...
With an increasing penetration of distributed energy resources (DERs) in Energy Internet, there is a surge of interest in distributed economic dispatch (DED) problems. The existing literature mainly focuses on average consensus algorithms, the convergence of which remains a bottleneck in practical applications. To improve the convergence rate of DED, this paper proposes a consensus algorithm based on optimized transition matrix (TM) of Markov chain. A DED model is firstly developed under a consensus-based information exchange architecture, in which a generator only communicates with its neighbors. Thus DED is implemented in an iterative manner with generators exchanging information according to a predefined TM. In contrast to the aver-agely weighted TM, we minimize the Frobenius norm (F-norm) of the TM in order to limit the eigenvalues that greatly influence the convergence rate of DED. Additionally, a virtual power method is introduced to meet generators' power limits by reformulating the power allocation ratio. Case studies verify the effectiveness and efficiency of the proposed algorithm.
Because the fault characteristics is not obvious, the high resistance grounding fault feeder selection in a resonant grounding system has always been a hot and difficult problem in the field of power system protection...
ISBN:
(数字)9781839531248
ISBN:
(纸本)9781839531255
Because the fault characteristics is not obvious, the high resistance grounding fault feeder selection in a resonant grounding system has always been a hot and difficult problem in the field of power system protection. To solve this problem, the expressions of the transient zero sequence current of each feeder under over-damping and under-damping conditions are obtained based on the transient equivalent circuit of high resistance grounding fault in a resonant grounding system. The correlation degree of the transient zero sequence current between any two feeders is analysed by using the correlation coefficient method, so as to realize the fault feeder selection for high resistance grounding fault. simulation results of PSCAD software show that this method is not affected by transition resistance, initial phase angle of fault, and has high accuracy and reliability.
Photovoltaic cells are being increasingly installed worldwide as a type of important renewable resource for powergeneration. Among the installed photovoltaic systems, data are collected from the control and monitorin...
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ISBN:
(数字)9781728170503
ISBN:
(纸本)9781728170510
Photovoltaic cells are being increasingly installed worldwide as a type of important renewable resource for powergeneration. Among the installed photovoltaic systems, data are collected from the control and monitoring system, and the anomaly detection researches are mostly based on the individual photovoltaic cells and the systematic behavior in a group of photovoltaic systems is not well studied. Based on the assumption that the photovoltaic cells installed in the same location are with very close solar radiation, the power output of each subsystem is considered in this work for monitoring the operating status of the subsystem and identifying the anomalous subsystem, where spatiotemporal pattern network, a probabilistic graphical modeling approach, is applied. The results show that the presented framework is able to detect the anomaly and locate the anomalous subsystem.
Demands for high-power converters are increasing rapidly. Nevertheless, due to their complex structures and multi-time-scale features, accurate and efficient simulation of such systems has long been a huge obstacle. A...
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Demands for high-power converters are increasing rapidly. Nevertheless, due to their complex structures and multi-time-scale features, accurate and efficient simulation of such systems has long been a huge obstacle. Aiming at improving the unacceptably slow simulation speed of high-power converters, this paper improves Discrete state Event-Driven (DSED) approach by implementing a decoupling method. Taking a 10kV 1MW electric energy router as an example, this paper evaluates the effectiveness of DSED with the proposed decoupling method in high-power applications. In the studied case, compared with commercially available tool for power electronics simulation, PLECS, DSED can achieve an up to 1000-fold improvement in simulation speed under the same accuracy: PLECS takes 6 hours while DSED only takes 18 seconds. DSED provides a powerful simulation tool for analysis, design and control of high-power converters.
Imbalance of generation and load caused by volatile generations poses challenges on frequency regulation. AGC is required to respond to the generation fluctuations without violating operational and security constraint...
Imbalance of generation and load caused by volatile generations poses challenges on frequency regulation. AGC is required to respond to the generation fluctuations without violating operational and security constraints. While explicit model predictive control (EMPC) provides an approach, the partition number of the piecewise affine control laws grows exponentially with the number of constraints and prediction/control horizons, which hinders its application in large systems. In this paper, we propose an EMPC approach for AGC by approximating the control laws using Legendre polynomial series expansions, thus entirely eliminating the partition issue. Galerkin method is applied to the KKT conditions of EMPC's multiparametric quadratic programming (mp-QP) problem to compute the approximations. Case study in New England 39-bus system verifies the performance and efficiency of the proposed controller.
The problem of high resistance grounding fault detection in resonant grounding system is always the pain point and difficulty in the field of power system research. To solve the problem, based on PSCAD software, this ...
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ISBN:
(数字)9781728117225
ISBN:
(纸本)9781728117232
The problem of high resistance grounding fault detection in resonant grounding system is always the pain point and difficulty in the field of power system research. To solve the problem, based on PSCAD software, this paper firstly establishes a typical distribution system model, and analyzes the relationship between the transient component, traveling wave component and the fault initial angle, transition resistance value and arc. Secondly, this paper analyzes the effect of the main fault detection methods such as transient methods and travelling wave method, and gives the effective domain of different detection methods. Above analysis establishes a complete systematic test scheme for the high resistance grounding fault detection, and provides an effective test support for the subsequent effectual fault detection method for high resistance grounding fault.
The beat frequency characteristic of the recovery voltage of fault phase in the case of single-phase grounding transient fault happening to line with the shunt reactors is analyzed. Besides, the paper analyzes the rea...
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ISBN:
(数字)9781728117225
ISBN:
(纸本)9781728117232
The beat frequency characteristic of the recovery voltage of fault phase in the case of single-phase grounding transient fault happening to line with the shunt reactors is analyzed. Besides, the paper analyzes the reason of no beat frequency phenomenon of transient fault happening to line without shunt reactor. The AC power networks with metallic grounding fault and arc grounding fault are analyzed by simulation. The recovery voltage of single-phase grounding fault in AC/DC hybrid power grid is studied by PSCAD. The new problems of the adaptive re-closure in AC-DC hybrid power system are discussed. Then the follow-up ideas to solve several existing problems are also presented.
Wind power ultra-short-term prediction plays a key role in day scheduling of powersystems and cross-provincial power trading. However, the randomness and non-stationary nature of wind power, and the mismatch between ...
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Wind power ultra-short-term prediction plays a key role in day scheduling of powersystems and cross-provincial power trading. However, the randomness and non-stationary nature of wind power, and the mismatch between the training data and the predicted data have become the main obstacles for the improvement of prediction accuracy. This paper proposes a prediction algorithm based on variational mode decomposition(VMD) and clustering. Firstly, the original non-stationary sequence is transformed into several relatively stationary modes utilizing VMD. Secondly, key features can be conveniently selected for each mode, which has a central frequency. Then the k-means clustering method is used to cluster each mode into several typical patterns based on correlation coefficient based distance definition. Finally, the method of "offline training, online matching" is adopted to perform training and prediction process. The actual data of a wind farm in Jilin Province was used to verify the results. The results show that the proposed method can improve the accuracy of ultra-short-term in multi-step prediction of wind power.
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