Direct torque control (DTC) has achieved utilization on two-level inverters and three-level diode-clamped inverters, and it has high performance of speed control. But DTC hasn't been utilized to cascaded multileve...
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With the electrical load increasing rapidly, the fault probability of power equipment is also rising greatly. This paper put forwards a new method of monitoring transformer-running state based on acoustic wave analysi...
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ISBN:
(纸本)0863416381
With the electrical load increasing rapidly, the fault probability of power equipment is also rising greatly. This paper put forwards a new method of monitoring transformer-running state based on acoustic wave analysis. Firstly, the acoustic wave signal of the transformer running is collected by the system on chip (SOC) microcomputer. Then the signal is stored by a high-capacity secure memory (SD) card. The sound intensity and spectrum of acoustic wave is different when the power transformer running between normal and abnormal condition. Finally, the fuzzy algorithm is utilized to analyze the state of transformer. It is proved that the monitoringsystem based on acoustic wave analyzing can find the transformer's incipient fault on-line, and the transformer running safety and reliability can be assurance effectively.
A method of the thyristor rapi switched capacitors is presented in this paper, which breaks through the bondage of the conventional methods. In addition, a novel algorithm of two time reactive power has been presented...
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ISBN:
(纸本)0863412467
A method of the thyristor rapi switched capacitors is presented in this paper, which breaks through the bondage of the conventional methods. In addition, a novel algorithm of two time reactive power has been presented, with which reactive power can be calculated fast. Meanwhile, with microcomputer synchronous phase lock technology, quick switching without transition can be realized, dynamic reactive compensation for impact load can be achieved, and the total response time is shorter than 16 ms. This technology not only can compensate reactive current dynamically but also can improve the voltage waveform to a certain extent. In the end, the type test waveforms and the users' field test waveforms are given to show the validity and effectiveness of this technology. This method is an effective way to improve power quality.
It is a new method that monitoring the power equipments state based on image analyzing, and it can improve the automatic level of powersystem. Not only the video frequency would be monitored and recoded, but also the...
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ISBN:
(纸本)0863416381
It is a new method that monitoring the power equipments state based on image analyzing, and it can improve the automatic level of powersystem. Not only the video frequency would be monitored and recoded, but also the images analyzing and recognizing can be done, and it leads the incipient fault to be discovered on-line. The computer captures remote equipments images, calculates images' moment invariants as characteristic vector of recognition, recognizes power equipments by support vector machine (SVM). The system further analyzes images and find if images has convex hull, intensive stochastic noise, or false edges, sequently make a conclusion whether the running state of equipments is in order. Replace of scouting by people themselves, the use of image recognition in powersystem can timely find troubles and potential troubles of power equipments. So the power equipments can be inspected and maintains its working state, which would improve the running reliability of the unattended substation.
UPQC (unified power quality conditioner), which assembles a series voltage compensator;a shunt current compensator and an energy storage device, is the emerging device of custom power. Multiple power quality regulatio...
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ISBN:
(纸本)0863412467
UPQC (unified power quality conditioner), which assembles a series voltage compensator;a shunt current compensator and an energy storage device, is the emerging device of custom power. Multiple power quality regulation functions are implemented in UPQC simultaneously. Synthetic compensating functions of UPQC are explained systematically, and a typical topological circuit of UPQC is proposed. For further improvement of the performance of UPQC, APFC (active power factor correction) is introduced to the DC capacitive voltage control for storage unit of UPQC;moreover its working principle is expounded in detail, simulation results are presented to testify the validity of this approach. It is feasible to apply APFC to the storage unit of UPQC, which makes the performance excellent.
The research on the methodologies and implementation strategies in bulk powersystem restoration after a partial or complete collapse is of great significance. This paper provides the survey on the recent developments...
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ISBN:
(纸本)0863412467
The research on the methodologies and implementation strategies in bulk powersystem restoration after a partial or complete collapse is of great significance. This paper provides the survey on the recent developments of restoration methodologies and implementation strategies. And many new ways to form a powersystem restoration plan and how to deal with the sub-problems encountered during the restoration process are summarized and introduced. Also, the future work are presented, such as, how to consider the AC/DC hybrid system in the restoration process, how to utilize the distributed generation (DG) and how to use the wide-area measurement system (WAMS) for restoration.
With the interconnection of power grid, the postdisturbance system is easier to suffer power-angle swing and system oscillation. Moreover, the impact of load characteristics on the systemdynamic behavior becomes more...
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In order to develop the IEC standard based flicker meter, analog model of the flicker meter is developed by Matlab according to the functions and design criterion suggested by IEC. After making certain the analog mode...
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ISBN:
(纸本)0863416381
In order to develop the IEC standard based flicker meter, analog model of the flicker meter is developed by Matlab according to the functions and design criterion suggested by IEC. After making certain the analog model parameters and the sampling frequency, bilinear transformation is adopted to converte the analog model to digital system. DSP-based digital flicker meter is developed based on the simulation results, and it is proved to be high-precision by simulation and experimental results. It can match the precision requirement of IEC standard.
Energy extraction and control of dynamic voltage restorer (DVR) have been warmly discussed. This paper presents and studies high frequency reversible rectifier based energy extraction of DVR. Researches three operatin...
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ISBN:
(纸本)0863412467
Energy extraction and control of dynamic voltage restorer (DVR) have been warmly discussed. This paper presents and studies high frequency reversible rectifier based energy extraction of DVR. Researches three operating modes of rectifier and its controlundersystem balance, single phase voltage sag, regeneration three conditions based on simulation. Results verified the correction and validity of presented control strategy and algorithm.
With the development of grid- interconnection and the commission of power electronic devices, the dynamic behaviors of powersystems become more and more complex. Once there is a disturbance, large area of outages mig...
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ISBN:
(纸本)0863412467
With the development of grid- interconnection and the commission of power electronic devices, the dynamic behaviors of powersystems become more and more complex. Once there is a disturbance, large area of outages might be occurred without effective transient stability analysis and control methods. The advent of WAMS gives a new way to transient stability analysis. In this paper, a new criterion of transient stability assessment is proposed based on COI system. Finally, numerical simulations are conducted on IEEE-9 bus system to demonstrate the effectiveness of the criterion.
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