short circuit test
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Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 492
Author(s):  
Karlo Petrović ◽  
Antonio Petošić ◽  
Tomislav Župan

In this work, the vibrations on the surfaces of the tank wall, stiffeners, and the cover of a 5 MVA transformer experimental model were measured during open-circuit and short-circuit transformer tests. Vibration measurements of a transformer tank side were conducted at discrete points using two different voltage sources in no-load test. Using interpolation functions, the RMS values of acceleration and vibration velocity are visualized and compared for each considered measurement configuration (no-load and load tests and two different excitation sources). Significant differences in mode shapes and amplitudes of vibrations at different frequencies are observed. The maximum RMS values of acceleration, velocity and displacement in the open-circuit test are 0.36 m/s2, 0.31 mm/s, and 0.42 µm, respectively. The maximum values in short-circuit test are 0.74 m/s2, 1.14 mm/s, and 1.8 µm, respectively. In the short-circuit test, the frequency component of 100 Hz is dominant. In the open-circuit test, the first few 100 Hz harmonics are significant (100 Hz, 200 Hz, and 300 Hz). In addition to the visualization of RMS values during the open-circuit and short-circuit tests, animations of the vibrations are created. Fourier analysis and phase comparison between frequency components are also used to show vibration animations at dominant frequencies in the spectrum (100 Hz harmonics). The visualization of the vibrations at the tank wall surfaces is transferred into 3D space in such a way that all 15 surfaces are mapped to the spatial coordinates of the surfaces so that a 3D model of the acceleration, vibration velocity, and displacement of the transformer tank is shown.


2022 ◽  
Vol 354 ◽  
pp. 00040
Author(s):  
Marius Darie ◽  
Tiberiu Csaszar ◽  
Adriana Andriș ◽  
Ioana Ciobanu

In paperwork is presented the estimation of the maximum surface temperature of cells exposed to specific tests for the intrinsic safety type of protection. Particularly, it presents the thermal resistance of the short-circuit test-stand results. The first part introduces the aspects regarding the risk of explosion. The risk of explosion occurs due to the presence of technical equipment in areas where flammable substances may occur. The second part itemizes the requirements for the testing of cells. Also, is introduced the stand configuration and performance aspects. The third part of the paper has been dedicated to the presentation and the discussion of the obtained results. The analysis of the test results highlighted the range of thermal resistance. This result could help estimation of the surface temperature of cells based on their capacity and internal resistance. The convection coefficients were determined. The process of deep discharge destroys the inner electrochemical of the cell system. Therefore, it permits energy recovery lower than a fraction of a tenth.


2021 ◽  
Author(s):  
Wei Qin ◽  
Tiansong Gu ◽  
Hongliang Li

Inter-turn short circuit is a common fault in reactor. In view of the current situation of insufficient condition based maintenance of reactor, an on-line monitoring method suitable for Inter-turn short circuit fault of distribution reactor was proposed in this paper. Firstly, the equivalent circuit model of reactor was built, and the calculation method of electrical parameters of reactor was obtained; Then, a set of on-line monitoring system for reactor short-circuit fault was built. Finally, the short-circuit test of reactor under different fault location and fault degree was carried out. The results show that the equivalent reactance and resistance change rate of inter-turn short circuit of reactor have the symmetry of short circuit position, the absolute value of change rate in the middle is the largest, and the absolute value of change rate at both ends is the smallest. With the deepening of short-circuit fault, the equivalent reactance decreases and the decreasing range increases. The equivalent resistance shows an increasing trend, and the increasing range increases. This research technology can realize the effective monitoring of inter-turn short circuit fault of distribution reactor.


2021 ◽  
Author(s):  
Frederic Maurer ◽  
Jonas Kristiansen Nøland

The sudden short-circuit is considered the gold-standard parameter measurement method for wound-field synchronous machines (WFSMs) as it enables the recording of the characteristic quantities in near-to-real conditions. However, the test needs huge pieces of equipment, but even worse, it reduces the lifetime of the electrical components by up to 10 years due to the high winding overhang mechanical forces. The DC-Decay tests are low-power alternatives to obtain the characteristic quantities without damaging the machinery. To allow wider use of this method, there are a couple of challenges left that are tackled by this paper. The two main open challenges are, firstly, the number of measurements needed to reach a particular precision, and secondly, a comparison of the DC-Decay with the sudden short-circuit test to allow the validation against the gold standard. More detailed, this paper explores the main challenges associated with the practical use of the DC decay method, which is a non-conventional and detailed-level approach to characterize WFSMs. We provide replies and recommendations regarding the number of measurements, suggesting the minimum number of recorded tests needed to obtain the equivalent diagram with a given accuracy, which has been further validated with an experimental case study. Moreover, the potential enhancement and precision of the parameter identification algorithm are studied in detail. Finally, the equivalent parameters of the DC decay method are compared to the gold standard, which concludes on what the characterization means in terms of predicting accurate transient short-circuit currents for WFSMs.


2021 ◽  
Author(s):  
Frederic Maurer ◽  
Jonas Kristiansen Nøland

The sudden short-circuit is considered the gold-standard parameter measurement method for wound-field synchronous machines (WFSMs) as it enables the recording of the characteristic quantities in near-to-real conditions. However, the test needs huge pieces of equipment, but even worse, it reduces the lifetime of the electrical components by up to 10 years due to the high winding overhang mechanical forces. The DC-Decay tests are low-power alternatives to obtain the characteristic quantities without damaging the machinery. To allow wider use of this method, there are a couple of challenges left that are tackled by this paper. The two main open challenges are, firstly, the number of measurements needed to reach a particular precision, and secondly, a comparison of the DC-Decay with the sudden short-circuit test to allow the validation against the gold standard. More detailed, this paper explores the main challenges associated with the practical use of the DC decay method, which is a non-conventional and detailed-level approach to characterize WFSMs. We provide replies and recommendations regarding the number of measurements, suggesting the minimum number of recorded tests needed to obtain the equivalent diagram with a given accuracy, which has been further validated with an experimental case study. Moreover, the potential enhancement and precision of the parameter identification algorithm are studied in detail. Finally, the equivalent parameters of the DC decay method are compared to the gold standard, which concludes on what the characterization means in terms of predicting accurate transient short-circuit currents for WFSMs.


Author(s):  
He Dongsheng ◽  
Jia Zhidong ◽  
Lin Zhili ◽  
Luo Haiao ◽  
Miao Benjian ◽  
...  

Abstract The short-circuit withstand capability test of distribution transformer has the characteristics of long test period, high cost, strong destructiveness, low qualification rate, and can not be verified by simulation or calculation. It has become the bottleneck restricting the engineering and industrialization development of transformer industry. Based on experimental big data, this paper uses the expert diagnosis method of fuzzy mathematics to establish a superior evaluation model. The typical design process of distribution transformers is scored by experts, and the short-circuit passing rate is calculated according to the real short-circuit test data. Linear regression analysis is used to establish the regression equation, and a pre-diagnosis technique for short-circuit withstand capability of distribution transformers is proposed. At the same time, the validity of the model is verified by the actual case, and the accurate pre-diagnosis of the resistance to short-circuit capability is realized. It breaks through the common key technologies of the transformer industry and provides an early warning for the quality control of power grid pro-ducts and the elimination of hidden danger products. It has important theoretical guiding significance and engineering application value.


2021 ◽  
Vol 1885 (4) ◽  
pp. 042055
Author(s):  
Xiaoxiao Luo ◽  
Qianbo Xiao ◽  
Qian Wang ◽  
Zhiping Sheng

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