Due to the three-phase-to-three-leg direct matrix converter (3 × 3 MC) cannot be achieved with unbalanced load, then the three-phase-to-four-leg direct matrix converter (3 × 4 MC) is introduced. A novel modu...
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Integrated Energy system (IES), which plays a vital role in the development of Energy Internet (EI), can improve the efficiency of energy utilization and integration of renewable energy. However, the coupling between ...
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(数字)9781839530043
Integrated Energy system (IES), which plays a vital role in the development of Energy Internet (EI), can improve the efficiency of energy utilization and integration of renewable energy. However, the coupling between multiple energy systems will bring new challenges to the security control of the IES, such as combined heat and power (CHP) system. For IES, the preventive control is the first line of defense to ensure that the system can keep stable operation when contingencies such as the transmission outage or generator outage happen. This paper proposes a preventive control approach for CHP system, in which a day-ahead security constrained economic dispatch (SCED) model of CHP system considering the coupling of heat and electric is formulated. The model aims to minimize the cost of the whole system, while the preventive control of the system can be achieved with the constraints considering the normal states and contingencies states. Case studies based on the IEEE 9-bus system with CHPs are presented to illustrate the approach. The case result shows that the combined electric and heat optimal dispatch is more economical than when two systems are independently optimized and operated. And the proposed preventive control approach of the CHP system can satisfy both the electric and heat demand, and system security is ensured when the N-1 contingencies happened.
Due to the development of the energy interconnection, smart distribution networks (SDNs) should needs be transformed and upgraded to meet new demands. In order to assess the SDN planning, a new index system was conduc...
Due to the development of the energy interconnection, smart distribution networks (SDNs) should needs be transformed and upgraded to meet new demands. In order to assess the SDN planning, a new index system was conducted from the five attributes. The quantitative methods of all criteria were also defined. An evaluation model was proposed based on AHP weighting and TOPSIS methods. Empirical analysis was performed to verify the feasibility of the evaluation system.
Vuilleumier cycle was first patented in 1918. It was usually regard as the thermal-driven Stirling refrigeration cycle, which combined the low-frequency working pattern like Giffod-Mcmahon (GM) cryocooler and the comp...
Vuilleumier cycle was first patented in 1918. It was usually regard as the thermal-driven Stirling refrigeration cycle, which combined the low-frequency working pattern like Giffod-Mcmahon (GM) cryocooler and the compactness of Stirling-type cryocooler. With the continuous development in the past 100 years, the Vuilleumier-type (VM-type) cryocoolers have to been proved to generate cooling power from ambient temperature to liquid nitrogen temperature and even to liquid helium temperature. In recent decades, some efforts were made on traditional displacer-type VM cryocooler, Vuilleumier hybrid pulse tube cryocooler (VM-HPTC) and the VM-type pulse tube cryocooler (VM-type PTC) to obtain the liquid helium temperature. Successfully, not only the 4 K was obtained, but also the limit temperature of oscillating cryocooler by He4 was hit. This paper presents the progress of the 4 K-class VM-type cryocooler and analyzed the possible applications of 4 K class VM-type cryocooler.
power electronic zigzag transformer is an attractive solution for the flexible interconnection of smart distribution *** is constituted by slow-response and low-precision thyristor converters and fast-response and hig...
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power electronic zigzag transformer is an attractive solution for the flexible interconnection of smart distribution *** is constituted by slow-response and low-precision thyristor converters and fast-response and high-accuracy voltage source *** paper models its primary circuit and addresses its basic operation *** a dual-timescale control scheme is investigated to realize the coordinated regulation of both types of converter.A simulation case is established in PSCAD containing interconnected mid-voltage distribution *** with poor-and well-matched control timescales are both carried *** accordingly,the power flow controllability under these conditions is *** the shorter control timescale is no more than tenth of the longer one,the power electronic zigzag transformer will operate with satisfying performances.
Modifying the equivalent rotor resistivity with rotor end factor in 2-dimension(2-D)finite element analysis(FEA)is an effective way to analyze the 3-dimension(3-D)solid rotor *** the smooth solid rotor,five different ...
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Modifying the equivalent rotor resistivity with rotor end factor in 2-dimension(2-D)finite element analysis(FEA)is an effective way to analyze the 3-dimension(3-D)solid rotor *** the smooth solid rotor,five different rotor end factors are discussed and compared with each *** is theoretically clarified that the resistivity of rotor in 2-D FEA should be multiplied by the square of rotor end factors to take the 3-D end effect of solid rotor into *** the slitted solid rotor,an improved rotor end factor is proposed based on the equivalent area algorithm of eddy currents in rotor,since the end factors of smooth solid rotor are not ***,the time-harmonic finite element method(FEM)combined with the rotor end factor is applied to analyze the performance of solid rotor induction *** tested and computed results are in good agreement,which proves the effectiveness of rotor end factor for the simplication of 3-D solid rotor problems.
very-fast transient overvoltage (VFTO)-related problems are raising growing concerns in China with the development of ultra-high voltage. The practice of fitting ferrite rings on gas-insulated switchgear busbars for V...
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The strong coupling of electricity and heat of combined heat and power (CHP) unit in cold season results in the loss of flexibility, which may cause massive wind power curtailment if they are in the same system. This ...
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Integrated Energy system is beneficial for promoting the distributed renewable energy (DRE) consumption, thereby alleviating environmental pollution and energy shortage. In this paper, we propose a virtual power plant...
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