Topic
Isolation transformer
About: Isolation transformer is a research topic. Over the lifetime, 8145 publications have been published within this topic receiving 72396 citations.
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Papers
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25 Mar 1997
TL;DR: In this paper, a termination is provided for a differential transmission line such as unshielded twisted pair (UTP) to isolate a connected device from electromagnetic interference present on the UTP in the form of differential mode and common mode noise.
Abstract: A termination is provided for a differential transmission line such as unshielded twisted pair (UTP) to isolate a connected device from electromagnetic interference present on the UTP in the form of differential mode and common mode noise. An example of an electromagnetic interference isolator comprises a common mode and a differential mode termination, a common mode choke which exhibits substantially constant impedance over a wide bandwidth and a centre tapped isolation transformer.
66 citations
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20 Jun 2007TL;DR: In this article, a voltage detection circuit is provided with an isolation transformer having its primary side connected to battery 2 connection nodes 10, a switching device 5 connected to the primary side of the isolation transformer 4, an isolated input circuit 7 that switches the switching devices 5 ON and OFF, and a secondary voltage detection section 8 that detects output voltage from the secondary side.
Abstract: The voltage detection circuit 3 is provided with an isolation transformer 4 having its primary side connected to battery 2 connection nodes 10, a switching device 5 connected to the primary side of the isolation transformer 4, an isolated input circuit 7 that switches the switching device 5 ON and OFF, and a secondary voltage detection section 8 that detects output voltage from the secondary side of the isolation transformer 4. In the voltage detection circuit 3, the series input circuit 6 of the isolation transformer 4 primary side and the switching device 5 are connected to battery 2 measurement nodes, the switching device 5 is switched ON and OFF with a given periodicity by the isolated input circuit 7, and the output voltage from the secondary side of the isolation transformer 4 is detected by the secondary voltage detection section 8 to determine the voltage across the measurement nodes.
65 citations
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TL;DR: In this paper, a prefluxing strategy was proposed to reduce the inrush currents in a single-phase transformer by setting the residual flux to a known polarity after the transformer has been de-energized.
Abstract: Power transformers can experience large inrush currents upon energization, the severity of which depends on the source strength, the leakage impedance and residual flux of the transformer, and the angle of the applied voltage at energization. A novel inrush current reduction strategy has been implemented which involves setting a single-phase transformer's residual flux to a known polarity after the transformer has been de-energized, a process called “prefluxing,” and controlling the instant of transformer energization based on the flux polarity, seeking not to eliminate inrush current but to substantially reduce it. Unlike a popular suggested solution, this strategy does not require prior knowledge of the transformer's flux. The device used for prefluxing is simple in construction and operates at substantially lower voltage levels when compared to the transformer's rated voltage. The presented strategy has been successfully implemented on an 18-kVA laboratory transformer with inrush current levels reduced below the rated current of the transformer even when accounting for typical breaker deviations. This paper describes the operation of the reduction strategy, including theory, device sizing, and implementation, and presents the successful laboratory results, all of which provide the basis for implementing inrush current reduction in three-phase transformers using a three-pole circuit breaker.
65 citations
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15 Mar 2015TL;DR: In this paper, the authors describe a design methodology taking into account the loss calculation, isolation requirements and thermal management, and an optimization process with a wide range of parameter variations is applied on a design example to find the highest power density while the efficiency, isolation and leakage inductance requirements are all met.
Abstract: The high power medium frequency transformer (HPMFT) is one of the key elements of an isolated, bi-directional DC-DC converters in applications such as future all-DC offshore wind farms, traction and solid state transformers. This paper describes a design methodology taking into account the loss calculation, isolation requirements and thermal management. Incorporating this design methodology, an optimization process with a wide range of parameter variations is applied on a design example to find the highest power density while the efficiency, isolation, thermal and leakage inductance requirements are all met.
65 citations
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01 Sep 2001TL;DR: In this article, a method to calculate the high-frequency transients in the transformer winding is developed based on multiconductor transmission-line theory, which is applicable to transients of frequencies up to several megahertz.
Abstract: Very fast transient overvoltages generated in gas-insulated switchgear could cause a voltage oscillation inside the connected transformer. A practical method to calculate the high-frequency transients in the transformer winding is developed based on multiconductor transmission-line theory. Resonance characteristics of a transformer are assessed using the inductance matrix obtainable from its winding geometry. Applicability to transients of frequencies up to several megahertz is checked in a model transformer and an actual 500 kV transformer. The calculated interturn voltage waveforms are in particularly good agreement with experiment.
65 citations