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This paper briefly discusses the working principle of synthetic aperture microwave radiometer system. Through the system sensitivity and repeatability test, The sensitivity and repeatability of the system are obtained. Based on the test, a correction algorithm for calibration error of calibration network sensitivity and receiver repeatability is proposed, which can be used to calibrate the data in...
Either soil moisture or ocean salinity plays important role in globe water cycle. They are key parameters for monitoring the globe climate change [1]. Aperture Synthesis Microwave Imaging Radiometer will measure global sea surface salinity with 50-km spatial resolution, and the average monthly salinity accuracy aims at 0.1 psu (parts per thousand). This requires the radiometer has long-term calibration...
L\X-band Full Polarization Aperture Synthesis Microwave Radiometer (FPASMR) is a 2-D aperture synthesis radiometer working at L and X-band with full polarization measurement for obtaining high precise measurement of sea surface salinity. FPASMR consists of dual Y-shaped arrays containing 23 L-band antennas per arm plus one in the center in L-band array and the same numbers of X-band antennas in X-band...
In this paper, a L-band phased array radiometer for sea surface salinity is developed. To reduce the mass and volume of real-aperture microwave radiometers, the radiometer employs a phased array and a receiver channel, which can observe target scenes with electric scanning. The L-band phased radiometer is analyzed using noise waves. The calibration method of the radiometer is introduced. A Radio Frequency...
During the commissioning stage or pole outage of high-voltage direct current (HVDC) links, ground-return currents (GRCs) are injected into dc grounding electrodes. Therefore, earth surface potential (ESP) is induced by GRC. Moreover, nonuniform distribution of ESP in wide areas usually leads to half-cycle saturation of power transformers and interference of metallic underground infrastructures, especially...
Deep-well earth electrode has advantages of covering small area and investing few. Temperature rise is one of the key quantity to take into consideration during designing. After analyzing the current and temperature field, infinite length cylinder model is used to calculate the temperature, and the partial differential equation is deduced to express the temperature field. Uniform space temperature...
In the first part of this paper, the methodologies of earth resistivity measurement and estimation have been studied. The horizontal layered soil (HLS) model obtained by the first part of this paper is usually with over 10 layers, which is far more than the existing HLSs used for grounding design. The parameters of the HLS of wide areas are also irregular, which means the resistivity or thickness...
In aperture synthesis radiometers (ASRs), the mutual coupling effect between antennas is a key problem, which degrades the performance of ASRs and should be compensated. In this paper, an improved compensation method is proposed for ASRs, which is based on the receiving mutual impedance. The proposed method is verified by a one-dimension 5-channel L-band ASR. The experimental results show that the...
Room temperature vulcanized (RTV) silicone rubber is widely used in external insulation of electrical equipment for antipollution flashover because it has many merits such as superior hydrophobicity and migration of hydrophobicity, but it also has weakness such as poor aging performance. The study on the failure criterion of RTV silicone rubber is always a concern since there has been no generally...
Grounding grid performance when subject to lightning current are different when compared to power frequency environment. Various computer models have been developed to understand transient grounding performance. The models led to the introduction of an “effective area” concept. It is an important concept as the parameter is used to optimize grounding-grid design. Several approaches and numerical equations...
An analysis on properties of mechanical fatigue and solid insulation during aging process should be made to reveal which ones we have not found in previous studies. Especially, the initiation and growth of electrical trees and mechanical fatigue are extremely similar. In this paper, a detailed comparison is made according to the theory of electrical trees and mechanical fatigue, and a simulation is...
Adopting plusmn500 kV HVDC double circuit transmission lines to transmit power can both economize line corridor and add unit corridor aera transmission capacity, so plusmn500 kV HVDC double circuit transmission lines are more and more adopted. Because the length of double circuit transmission lines is high, it is more likely to be attacked by lightning stroke, so lightning performance for double circuit...
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