A new method for partial discharge (PD) location in oil is presented based on ultrasonic phased array and wideband array signal processing. Firstly, the wideband ultrasonic signal of PD is measured directly by the ult...
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A novel SVC topology is proposed in this paper, firstly a multi-winding transformer is adopt to realize 12 ripple, secondly the 5th harmonic filter on system bus as the fundamental reactive power compensation, and con...
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ISBN:
(纸本)9781424427994
A novel SVC topology is proposed in this paper, firstly a multi-winding transformer is adopt to realize 12 ripple, secondly the 5th harmonic filter on system bus as the fundamental reactive power compensation, and control thyristor controlled reactor (TCR) to realize inflow system reactive power, thirdly modularization design is adopted, according to the compensation reactive power only one TCR module is phase controlled. Finally, the experimental result shows that the novel TCR without an additional filter has the advantages of low harmonic, good static and dynamic performance, small volume and etc, compared to traditional TCR.
This article is concerned with the impact of large-scale wind farms utilizing double fed induction generator (DFIG) on the transient stability to a general power system. In the first instance, the synthetical dynamic ...
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This article is concerned with the impact of large-scale wind farms utilizing double fed induction generator (DFIG) on the transient stability to a general power system. In the first instance, the synthetical dynamic model of the wind turbine generators (WTGs) is introduced, including pitch angle control model and the generator protective model. And then, the simulation is made to the CIGRE B4-39 standard grid through the comparison between synchronous generator integration and wind farm based DFIG integration with the same power capacity. The simulation is also contained after the load and the topological structure changed. The conclusion shows that the transient stability of the power system including DFIGs wind farm is more robust than conventional synchronous generator connected.
Along with consuming of fossil energy step by step, crisis of energy has been appeared. The solar energy, which is endless, is a kind of renewable energy. Radiation of sun coming to earth in a day is equal to the ener...
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Along with consuming of fossil energy step by step, crisis of energy has been appeared. The solar energy, which is endless, is a kind of renewable energy. Radiation of sun coming to earth in a day is equal to the energy, which is released by trillion buckets of oil. The research of solar energy generation has stepped into a very activity period. This paper analyses the physics characteristic of photovoltaic array firstly, then researches the mathematical model applying in engineering, and designs the total simulation model based on power electronic circuit in the end. In order to validate the correctness and validity, this paper makes a simulation as an example. The scheme can express the V-I characteristic of photovoltaic array very well.
Fast and accurate tracking of voltage flicker envelope is significant to the performance of flicker meter, flicker source location and the mitigation of voltage flicker. Using the energy of a signal and its shifted si...
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Fast and accurate tracking of voltage flicker envelope is significant to the performance of flicker meter, flicker source location and the mitigation of voltage flicker. Using the energy of a signal and its shifted signals to track the envelope of voltage flicker is presented in this paper. It is assumed that the signal is shifted, once by a lead angle equal to beta, and at another time by a lag angle equal to beta, which generates two new signals u + (t) and u - (t). According to the energy differences, the relationship between the flicker amplitude and u(t), u + (t), u - (t) can be obtained, so the voltage flicker envelope is successfully tracked. How to obtain the shifted signals u + (t), u - (t) is analyzed in the paper. The frequency error e f (%), amplitude error e m (%) and waveform standard deviation sigma(%) are used as the weighing index of the accuracy of tracking flicker envelope. The theoretical analyzing and RTDS simulation test verify that the suggested method is accurate, fast and anti-noise.
A good black-start scheme is important and necessary to resume power supply fast and efficiently after black out, and how to choose black-start power is the first thing to consider in the scheme. In this paper, the ad...
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ISBN:
(纸本)9781424449347
A good black-start scheme is important and necessary to resume power supply fast and efficiently after black out, and how to choose black-start power is the first thing to consider in the scheme. In this paper, the advantages of VSC-HVDC as black start power are analyzed with contrast to traditional black start power. The ability of VSC-HVDC to soft energize major power system equipment is proved through simulation by software PSCAD/EMTDC. Simulation waveforms during soft energization are illustrated. These plots have described the good voltage and frequency characteristics of VSC-HVDC. The transition from one control mode of VSC to another is also discussed. Simulation results indicate that by using soft energization, VSC-HVDC is an ideal black start power.
In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated qui...
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In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated quickly and defined exactly. In our researches, global information has been introduced into the backup protection system. By analyzing and computing real-time PMU measurements, basing on cluster analysis theory, we are using mainly hierarchical cluster analysis technology to seek after for the statistical laws of electrical quantities' marked changes. Then we carry out fast and exact identification of faulty components and faulty sections, and finally accomplish fault isolation. Multivariate statistical analysis theory is an efficient theory that can resolve different kinds of complex problems. It has been applied successfully in many researches of various fields, such as geology, weather, hydrology, iatrology, industry, agriculture, and economy, etc. In the study of electric power systems, multivariate statistical analysis theory must also have a good prospect of application.
Solar energy is considered as one of the most effective, less expensive, harmless and less environment pollution effect of renewable energy sources. The problem of using solar power including varying weather condition...
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ISBN:
(纸本)9781424449347
Solar energy is considered as one of the most effective, less expensive, harmless and less environment pollution effect of renewable energy sources. The problem of using solar power including varying weather condition brings different output power of the photovoltaic (PV) array, which may cause a serious waste of solar power. For solving this problem, a Maximum power point tracking (MPPT) strategy is always required to make PV array keep giving maximum power under different environment condition. In this paper, a variable step MPPT based on gradient descent method is proposed for faster and more precise tracking process. A model based on matlab/simulink was established to analysis the performance of the proposed MPPT strategy. Simulation proves that this MPPT method is practical with a better performance than the traditional strategies.
In this paper, based on Centralized Distributed model, a study method of reliability of WAMS is presented. The whole WAMS system is divided into two sub-systems: Monitor Center System and Data Acquisition System. The ...
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In this paper, based on Centralized Distributed model, a study method of reliability of WAMS is presented. The whole WAMS system is divided into two sub-systems: Monitor Center System and Data Acquisition System. The Communication System is also modeled as an auxiliary evaluation system. According to the Markov condition, the Monitor Center System establishes the Kolomogorov equation, sets the invalidation function based on the GO software model, and obtains the evaluation methods of its availability. The analysis of data acquisition system takes the phasor measurement unit and Phasor Data Concentrator (PDC), which installed in various protection areas, as the study objects, and gets the reliability evaluation of data acquisition system by the series system model, the parallel system model and k/n judgment system model of those facility units. The study method is used in the reliability evaluation of a real WAMS system of IEEE 14 Node. As the result shows that this reliability evolution method has a guiding significance in the practical application of WAMS system.
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