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Frequency domain spectroscopy (FDS) technique is regarded as an effective nondestructive diagnosis method of the insulating state for oil-paper insulation that has been widely researched worldwide. To quantify the dielectric's FDS character, a new explanation model of the dielectric loss with several parameters was first proposed after an in-depth study of the frequency-domain dielectric response...
In this paper, to effectively distinguish between the aging and moisture of oil-immersed paper (OIP), and to enhance the accuracy of the nondestructive diagnosis of the insulating state for oil-paper insulation, we perform an in-depth study of the frequencydomain dielectric response theory. First, we present a theoretical explanation for frequency-domain spectroscopy (FDS) based on investigations...
Moisture content of oil and paper is one of the most important factors influencing the dielectric behavior of insulation systems. Moisture estimation in insulating paper can provide a way to understand the real condition of insulation and helps to assess its remaining useful life. In recent years, Frequency Domain Spectroscopy (FDS) is widely used by power utilities for moisture estimation and condition...
In the present work, the formation of foam from leachate in a bench-scale Membrane Bio-reactor(MBR) was analyzed, and three kinds of defoamers (A (triethyl phosphate), B (fungicide), C(silicone) )was studied to control biologic foam by parallely pilot. The conclusions were that (1) During the analysis of foam components, the ash, moisture and bacteria composition ratio was different in the various...
New techniques are necessitated to be introduced for the diagnosis of large oil-immersed power equipments for the disadvantages of traditional methods such as not very good operability and accuracy. The Frequency Domain dielectric Spectroscopy (FDS) for the diagnosis of oil-paper insulation is presented in this paper. Specimens and on-site equipments under different conditions are measured using FDS...
Reliability of large oil-immersed power transformers is attracting more and more attention by the power system, and a lot of new test methods are being under research. In this paper, the dielectric response for oil-immersed transformer insulation condition and ageing diagnosis is introduced; a 220 kV transformer was measured utilizing frequency domain spectroscopy in China. The tan delta-f curves...
Moisture and ageing in power transformer strongly influence the dielectric properties of oil/paper insulation system. Moisture measurement in oil sample generally gives inconclusive information since oil/paper moisture equilibrium is temperature dependent and takes a long time to be in equilibrium. Direct moisture measurement of paper sample is not practicable for in-service transformers. The measurement...
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