The implementation of transmission expansion planning towards low carbon development can effectively alleviate the "carbon lock" effect in the power industry and facilitate the transition to low carbon power...
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Wind powergeneration uncertainty has imposed great challenge on powersystems' operation and should be considered when making an operation *** this paper,we focus on optimal power flow(OPF) problem in radial powe...
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ISBN:
(纸本)9781467374439
Wind powergeneration uncertainty has imposed great challenge on powersystems' operation and should be considered when making an operation *** this paper,we focus on optimal power flow(OPF) problem in radial power networks while considering wind powergeneration *** cope with this uncertainty,the stochastic AC-constrained OPF(ACOPF) problem considering both continuous and discrete devices is formulated based on our previous *** second order cone relaxation is employed to relax the original mixed integer nonconvex nonlinear programming(MINNLP) problem to a mixed integer second order cone programming(MISOCP) problem which can be solved by commercial solvers with high computation *** modified IEEE 33 bus distribution system is studied in this paper which validate the effectiveness of the proposed model.
The series connection of insulated gate bipolar transistors (IGBTs) allows the operation at voltage levels higher than the rated voltage of one IGBT. However, the technology has not been widely applied due to transien...
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ISBN:
(纸本)9781509007387
The series connection of insulated gate bipolar transistors (IGBTs) allows the operation at voltage levels higher than the rated voltage of one IGBT. However, the technology has not been widely applied due to transient voltage unbalance. Asynchronous gate drive signals, which cause series-connected IGBTs not to turn-on and turn-off at the same time, result in serious unbalanced voltage sharing. This paper presents an active voltage balancing control for multi series connected HV-IGBTs including the active voltage balancing control (AVBC) circuit integrated in the gate driver and the control for multi series connected IGBTs. The effectiveness of the control has been experimentally validated in a 10 kV dc-link voltage converter using four 4.5 kV HV-IGBTs in series connection.
DC microgrids are becoming popular in distribution systems based on its higher reliability and system efficiency. DC bus signal (DBS) control as a common control strategy was widely used in dc microgrids, in which, co...
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ISBN:
(纸本)9781467395519
DC microgrids are becoming popular in distribution systems based on its higher reliability and system efficiency. DC bus signal (DBS) control as a common control strategy was widely used in dc microgrids, in which, control mode of each power electronic converter is triggered by monitoring the dc voltage variation to keep the power balance of the dc microgrid. Most of the dc microgrid stability analysis are linear and based on the impedance matching theory. But the dc microgrid will be a nonlinear system when the operation mode was automatically switched based on switching information. In this paper, the switched system theory was used to analyze the stability of dc microgrids under DBS control strategy. The stability conditions in each subsystem and switched system was present in this paper and simulation results verify the effectiveness of the proposed criterion.
The integration and accommodation of the wind and solar energy pose great challenges on today’s powersystem operation due to the intermittent nature and volatility of the wind and solar *** efficient large-scale ele...
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The integration and accommodation of the wind and solar energy pose great challenges on today’s powersystem operation due to the intermittent nature and volatility of the wind and solar *** efficient large-scale electrical energy storage is one of the most effective and economical solutions to those *** the comprehensive review of the existing storage technologies,this paper proposes an overall design scheme for the Non-supplementary Fired Compressed Air Energy Storage(NFCAES)system,including system design,modeling and efficiency assessment,as well as protection and ***,the design principles of the multistage regenerative,*** recovery system which is used to fully recycle and utilize the waste heat from compression are provided,so as the overall system efficiency evaluation *** paper theoretically ascertains the storage decoupling rules in the potential and internal energy of molecular compressed air and reveals the conversion mechanism of gas,heat,power,electricity and other forms of *** this basis,a 500-k W physical simulationsystem of CAES system(TICC-500,Tsinghua-IPCCAS-CEPRI-CAES)is built,which passed a system-wide 420-k W load powergeneration test with less pollution and zero carbon ***,the multi-form energy conversion of multi-stage regenerative CAES and storage efficiency is verified,especially its incomparable superiority in solving the uncertainty problem in wind and solar power ***,the propaganda and application scenario of the CAES system in China is introduced.
The application of reduced common mode voltage pulse width modulation methods bring much high order harmonics to the variable speed drive system, which causes considerable iron loss inside the electric motor. In this ...
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Electrical tree break-down is the major failure problem in cable accessories, however, mechanisms of the electrical tree initiation and propagation are still lack of deeply research, especially in silicone rubber (SIR...
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Electrical tree break-down is the major failure problem in cable accessories, however, mechanisms of the electrical tree initiation and propagation are still lack of deeply research, especially in silicone rubber (SIR) which is widely used as insulation material for cable accessories. Long-term aging (0- 1000 h) experiments under the different voltages were conducted to observe electrical tree initiation and propagation processes. In trees initiation stage, with increasing of applied voltage, electrical tree initiation probability becomes larger, while tree initiation time dramatically decreases. The experiment observations demonstrated four shapes of trees which are dominated. As applied voltage increasing, the numbers of electrical trees life-cycles increased and exponential relationship was found between tree length and magnitude of applied voltage. It is noted that charges, whose energy exceeding a certain critical value, destroy microstructure of dielectric accumulatively via injection and extraction, and cause electrical trees initiate when it accumulates to a visible extent.
Time-varying frequency selective attenuation and colored noises are unfavorable characteristics of power line communication(PLC) channels of the low voltage *** overcome these disadvantages,a novel real-time dynamic s...
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Time-varying frequency selective attenuation and colored noises are unfavorable characteristics of power line communication(PLC) channels of the low voltage *** overcome these disadvantages,a novel real-time dynamic spectrum management(DSM) algorithm in orthogonal frequency division multiplexing(OFDM)-based high-speed narrow-band power line communication(HNPLC) systems is proposed,and the corresponding FPGA circuit is designed and *** of the proposed DSM is validated with a large amount of network experiments under practical PLC *** the noise in each narrow subcarrier is approximately Gaussian,the proposed DSM adopts the BER/SER expression formulized via the AWGN channel to provide a handy and universal strategy for power *** real-time requirement is guaranteed by choosing subcarriers in group and employing the same modulation scheme within each *** measures are suitable for any modulation scheme no matter the system criterion is to maximize data rate or minimize power/*** design and hardware implementation of the proposed DSM are given with some flexible and efficient *** DSM circuit is carried out with Xilinx *** and practical experiments validate that the proposed real-time DSM significantly improves system performance.
High impedance faults (HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse ...
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High impedance faults (HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse due to the limited fault current values and the situation is worse in wind farms. The mostly adopted HIF detection algorithms are based on the 3rd harmonic characteristic of the fault zero-sequence currents, whereas these 3rd harmonics are very easy to be polluted by wind power back-to-back converters. To solve this problem, the typical HIF arc flash based on Mayr's arc model is first built, and the typical fault waveforms of HIF in wind farm are presented. Then the characteristics of high impedance faults are analysed to distinguish the occurrence of HIF from other harmonic interference. After that, the performance of the traditional harmonic based HIF detection algorithm is discussed, and a novel detection algorithm is presented to prevent harmonic interference influence in wind farms.
The characterization of the closed-loop delays in a wide-area controlsystem (WACS) is an important foundation for further research. The method to estimate and measure the closed-loop delay in actual WACSs were propos...
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ISBN:
(纸本)9781509041695
The characterization of the closed-loop delays in a wide-area controlsystem (WACS) is an important foundation for further research. The method to estimate and measure the closed-loop delay in actual WACSs were proposed in this paper. Then, the closed-loop delays in the actual WACS in Guizhou power Grid in China were measured and analyzed. Also, the measured delays were used to verify the normal distribution estimation model proposed in previous research. The results indicate that the closed-loop delay in the WACS followed a normal distribution.
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