Hot dry rock is a new type of geothermal resource which has a promising application prospect in *** paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dry rock ...
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Hot dry rock is a new type of geothermal resource which has a promising application prospect in *** paper conducted a comparative research on performance evaluation of two eligible bottoming cycles for a hot dry rock power plant in the Gonghe *** on the given heat production conditions,a Kalina cycle and three organic Rankine cycles were tested respectively with different ammonia-water mixtures of seven ammonia mass fractions and nine ecofriendly working *** results show that the optimal ammonia mass fraction is 82%for the proposed bottoming Kalina cycle in view of maximum net power *** analysis suggests that wet fluids should be supercritical while dry fluids should be saturated at the inlet of turbine,*** maximum net power output of the organic Rankine cycle with dry fluids expanding from saturated state is higher than that of the other organic Rankine cycle combinations,and is far higher than the maximum net power output in all tested Kalina cycle *** the given heat production conditions of hot dry rock resource in the Gonghe Basin,the saturated organic Rankine cycle with the dry fluid butane as working fluid generates the largest amount of net power.
The inter-shaft bearing could simplify the supporting structure of a dual-rotor system, so it is widely used in rotating machinery like gas turbine engine. When monitoring the vibration of an inter-shaft bearing, sens...
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Advanced adiabatic compressed air energy storage (AA-CAES) could play an important role in power distribution system for mitigating the intermittency of distributed renewable generations and reducing the peak-valley d...
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Due to the complexity of the valve side winding voltage of the converter transformer, the insulation characteristics of the oil-impregnated pressboard(OIP) of the converter transformer are different from those of the ...
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Due to the complexity of the valve side winding voltage of the converter transformer, the insulation characteristics of the oil-impregnated pressboard(OIP) of the converter transformer are different from those of the traditional AC transformer. The study on effect of temperature on the creeping discharge characteristics of OIP under combined AC–DC voltage is seriously inadequate. Therefore, this paper investigates the characteristics of OIP creepage discharge under combined AC–DC voltage and discusses the influence of temperature on creepage discharge characteristics under different temperatures from 70 °C to 110 °C. The experimental results show that the partial discharge inception voltage and flashover voltage decrease with increasing temperature. The times of low amplitude discharge(LAD) decrease and amplitude of LAD increases. Simultaneously, the times of high amplitude discharge(HAD) gradually increase at each stage of creepage discharge with higher temperature. The analysis indicates that the charge carriers easily accumulate and quickly migrate directional movement along the electric field ahead of discharging. The residual charge carriers are more easily dissipated after *** ‘hump’ region of LAD moves to the direction of higher discharge magnitude. The interval time between two continuous discharges is shortened obviously. The concentration of HAD accelerates the development of OIP insulation creepage discharge. The temperature had an accelerating effect on the development of discharge in the OIP under applying voltage.
Attention to efficient and cost-effective utilize of energy has become a common view in the energy sector. A variety of microgrid energy management systems are developed and installed to achieve the goal. However, the...
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ISBN:
(数字)9781728143033
ISBN:
(纸本)9781728143040
Attention to efficient and cost-effective utilize of energy has become a common view in the energy sector. A variety of microgrid energy management systems are developed and installed to achieve the goal. However, the performance of the microgrid energy management system depends on some factors, such as forecast uncertainty, measurement error, and so forth. Among them, a series of handling technologies for the forecast uncertainty are the focus in this paper. It includes accuracy improvement of prediction program based on time series method, operation strategy adoption, real-time control scheme for the energy storage equipment, and proposes a robust rule to against the extreme situation as well. This not only achieves effective energy management, but also helps to avoid operation cost increasing induced by the transaction bias assessment through the improvement of energy scheduling accuracy. The effectiveness and validity of these means is verified in the constructed campus microgrids at Chonnam National University.
This paper proposes a wavelet-based data compression method to compress the recorded data of oscillations in powersystems for wide-area measurement systems. Actual recorded oscillations and simulated oscillations are...
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This paper proposes a wavelet-based data compression method to compress the recorded data of oscillations in powersystems for wide-area measurement systems. Actual recorded oscillations and simulated oscillations are compressed and reconstructed by the waveletbased data compression method to select the best wavelet functions and decomposition scales according to the criterion of the minimum compression distortion composite index, for a balanced consideration of compression performance and reconstruction accuracy. Based on the selections, the relationship between the oscillation frequency and the corresponding optimal wavelet and scale is discussed, and a piecewise linear model of the base-2 logarithm of the frequency and the order of the wavelet is developed, in which different pieces represent different scales. As a result, the wavelet function and decomposition scale can be selected according to the oscillation frequency. Compared with the wavelet-based data compression method with a fixed wavelet scale for disturbance signals and the real-time data compression method based on exception compression and swing door trending for oscillations, the proposed method can provide high compression ratios and low distortion rates.
The problem of high resistance grounding fault detection in resonant grounding system is always the pain point and difficulty in the field of powersystem research. To solve the problem, based on PSCAD software, this ...
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Distance protection is widely applied in High/Ultra- High Voltage AC transmission system. Impedance relay, the core element of distance protection, may operate incorrectly under power swing, so a power swing blocking ...
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In recent years, human electric shock accident caused by line fault of distribution system has happened all over the world. This kind of problem of high resistance grounding fault safety is becoming more and more the ...
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This paper studies the dynamic operation of a residential electric energy system with distributed renewable *** streams among the power grid, local renewable plant, storage unit, and demand are considered;the temporal...
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This paper studies the dynamic operation of a residential electric energy system with distributed renewable *** streams among the power grid, local renewable plant, storage unit, and demand are considered;the temporal volatility of renewable generation is described by an uncertainty set, and the optimal operation problem gives rise to a multi-stage robust optimization. To deal with the non-anticipativity issue, the robust model is solved via robust dual dynamic programming（RDDP）approach. The the cost-to-go function is approximated by iteratively updating the upper and lower bounds, which can be obtained from forward-pass and backward pass procedures. Case studies validate the performance and advantage of the proposed method.
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