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Small hydropower, as renewable green electricity, has always been aroused all the world concern. In the "Kyoto Protocol" framework aiming to reduce global greenhouse gas as the goal, the hydroelectric project is a very important class of CDM projects, how to strengthen international cooperation to accelerate the process of China's small hydropower development, and improve capacity for sustainable...
Distinguishing from the traditional denoising methods, this paper proposes a novel denoising algorithm according to the image-surface fitting after the Non-Uniform Triangular Partition. A given image can automatically be partitioned into different triangles with different dimensions and the bivariate polynomial is used to do the Optimal Quadratic Approximation to gray values of image in each sub-triangle...
The traditional direct power control (DPC) strategy exits the problems that the switching frequency is not fixed, the sampling frequency is high and so on. To combat these problems, a control system of improved virtual-flux control strategy with DPC (VF-DPC) is proposed in the paper. In order to overcome the problem that switching frequency is not fixed, hysteretic controller and switching table are...
A thorough analysis of the electromagnetic compatibility of power lines and neighboring railway is presented. The railway is located close to the transmission line that consists of a combination of overhead and underground conductors and cables. Electromagnetic interference caused by high voltage power lines can endanger the proper operation of the signal and protection systems of the railways and...
In China, the wind power is expanding very quickly. We examine a specific real wind farm in China and analyze the WRF (Weather Research and Forecasting) model forecasts with different physical configurations and spatial resolutions. The model short-term wind speed predictions for February 2008 are compared with a real data collected in a met tower in the wind farm at 10-min sampling rate. In our case...
A new fault prognosis method based on trend analysis of frequency component is proposed. The vibration signal of bearing or shaft of the steam turbo-generator set is transformed into frequency signal by Fast Fourier Transform. The different frequency components are classified according to sohre's chart. The amplitudes of different frequency components are ranked by time series. The trend of each frequency...
Since the cost of transformer can be divided into 50-60% for material, and the rest being labor costs and modest profit, therefore as the major amount of transformers costs is related to its raw materials, so it has a high importance in costs estimating process. This paper presents a new method to estimate transformers pricing. The method is based on multilayer perceptron neural network (MPNN) with...
This paper firstly used bipolar SPWM waveform generation method (regular sampling method) to generate waveform, and analyzed the harmonic wave of output voltage to design filter parameters accordingly, taking into account the dead-zone effect of the harmonic effects. Then it used current inner loop and voltage outer loop control strategy, using pole placement to design controller parameters, and joined...
For the facts that lots of low-temperature waste heat from industries (such as oil plants, chemical plants, power plants or steel plants) is abundant but rarely used, a series of analogue tests are conducted by using indoor high-temperature heat pump set-up. According to the tested data and results, the empirical expressions of all performance indexes are regressed under the condition of using R142b...
The copyrolysis of biomass/polyolefin mixture was performed to obtain gaseous hydrocarbons. The difference of the gaseous fractions was analyzed by gas chromatography (GC). The optimum condition for C3-C4 gases production was temperature 410°C, the biomass/polyolefin (in mass) mixtures ratio 1:1. At 410°C, the copyrolysis leaded to the production of more than 30% (in mass) of gases. It should be noted...
The forecast of production is an important resource for establishing policy. Aimed at the character of the agriculture system, the least squares support vector machine prediction model is given based on the principle of the statistical learning theory and structural risk minimization from the Service-Oriented Architecture. The result is given that the forecasting model is effective and offers a new...
Dispatching centers play an important role in safe and stable operation and also have a great importance observing economical usages. Basically stepwise dispatching system is corresponding to electrical network structures and the ministry of power management methods, and also has to be more flexible with future operation methods and able to coordinate with future structure of country power network...
Power grid intelligent alarm and fault diagnosis program mainly use breaker and relay action alarms. However, there may be misoperations existed in relays, which could leads to incorrect diagnosis results. With the development of digital substation and application of IEC61850, the secondary circuit signals are available from integrated automation system in substation. These signals may imply control...
This paper proposed a new AC signal detection method based on variable N synchronous sampling to solve the problems on the harmonic detection and analysis of periodic sin waveform in power grid. Comparing with the traditional fixed N synchronous sampling detection in which the number of sampled data is constant in a period, the key difference of the new method is that the period of sampling points...
The first condition of decreasing traffic jam and satisfaction equilibrium of traffic demand and supply is deemed to the construction of urban transportation infrastructures. Urban rail transit construction is the key of urban continual development. The main problem of urban rail transit construction is scarcity reasonable evaluation of construction sequencing and benefit in the process of construction...
When fault occurs in power grid, a lot of alarms and records are generated in substations. These are secondary circuit signals, fault recorder and PMU data. Fault recorder data contains the details of fault evolution, which can be used for diagnosis fault occurrence time, circuit breaker operation events. It is crucial for power grid diagnosis and intelligent alarm functions. However, the analysis...
Oil and coal is a finite, non-renewable resource, and an oil peak is inevitable. A 100% renewable energy system (RES) requires dramatic progress in the areas of demand reduction, efficient renewable energy harvesting and integrated storage. Currently, building sector is the largest consumer in UK. It is followed by transportation sector, which has significant links with the building energy systems...
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