Study of High Voltage Inductive Voltage Transformer for Transients and Ferroresonance

Author(s):  
Aishwarya Jahagirdar ◽  
Archana Thosar ◽  
V.P. Dhote
Author(s):  
Hao Liu ◽  
Feng Zhou ◽  
Lixue Chen ◽  
Min Lei ◽  
Xiaodong Yin ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7426
Author(s):  
Imene Mitiche ◽  
Tony McGrail ◽  
Philip Boreham ◽  
Alan Nesbitt ◽  
Gordon Morison

The reliability and health of bushings in high-voltage (HV) power transformers is essential in the power supply industry, as any unexpected failure can cause power outage leading to heavy financial losses. The challenge is to identify the point at which insulation deterioration puts the bushing at an unacceptable risk of failure. By monitoring relevant measurements we can trace any change that occurs and may indicate an anomaly in the equipment’s condition. In this work we propose a machine-learning-based method for real-time anomaly detection in current magnitude and phase angle from three bushing taps. The proposed method is fast, self-supervised and flexible. It consists of a Long Short-Term Memory Auto-Encoder (LSTMAE) network which learns the normal current and phase measurements of the bushing and detects any point when these measurements change based on the Mean Absolute Error (MAE) metric evaluation. This approach was successfully evaluated using real-world data measured from HV transformer bushings where anomalous events have been identified.


2020 ◽  
Vol 41 (Supplement_1) ◽  
pp. S158-S158
Author(s):  
Harold Campbell ◽  
Rabia Nizamani ◽  
Samuel W Jones ◽  
Bruce Cairns ◽  
Felicia N Williams

Abstract Introduction The art of pyrography, creating designs in wood with a thermal heat source, dates back to prehistory. Risks include cutaneous burns and airway injury. Fractal woodburning is a niche method of pyrography utilizing a high-voltage electrical source to burn branched designs – Lichtenberg patterns – into the surface of wood. While this technique has grown in popularity, the associated risks are not well described. Methods We describe a patient who presented to our burn center after sustaining high-voltage electrical burns from a homemade high-voltage device constructed for fractal woodburning. We also evaluated publicly reported cases of death or injury due to this technique. Results An otherwise healthy 17-year-old male was admitted to our burn center with injuries sustained while making fractal wood art. The patient improvised a high-voltage transformer from a discarded microwave, generating 2000 volts from household current. While using this device to burn Lichtenberg patterns in wood, he contacted the electrodes and sustained full-thickness electrical burns to the neck, chest, and bilateral upper extremities. Bilateral upper extremity fasciotomies were required on admission. Multiple subsequent operative procedures culminated with autografting to the majority of the wounds and ongoing complex reconstruction of the left thumb. In evaluating online news reports, we found 21 unique individuals with death or injury attributed to fractal woodburning. Four sustained substantial injuries, while 17 reportedly died. The first reported incident occurred in July 2016 and the most recent report was from July 2019. Ages ranged from 17 years old to the 60s. Eighteen individuals were younger than 50 years old. All of the mortalities and 3 of the 4 injuries occurred in males. Of the survivors, 3 sustained significant upper extremity injuries and 2 suffered cardiac arrest at the time of injury. The devices used in 4 incidents were microwave transformers and generated 2000 volts. Device characteristics were not identified in the remainder of cases. Conclusions Fractal woodburning is associated with devastating high-voltage electrical injuries and death. Prevention efforts should be focused on the potential risks of this art form. Applicability of Research to Practice News reports likely underestimate the actual incidence of injury and death due to fractal woodburning, however, even this limited data suggests an emerging public health problem requiring further study and public education.


Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1004 ◽  
Author(s):  
Carlo Olivieri ◽  
Francesco de Paulis ◽  
Antonio Orlandi ◽  
Giorgio Giannuzzi ◽  
Roberto Salvati ◽  
...  

This work presents the feasibility study of an on-line monitoring technique aimed to discover unwanted variations of longitudinal impedance along the line (also named “impedance discontinuities”) and, possibly, incipient faults typically occurring on high voltage power transmission lines, like those generated by oxidated midspan joints or bolted joints usually present on such lines. In this paper, the focus is placed on the application and proper customization of a technique based on the time-domain reflectometry (TDR) technique when applied to an in-service high-voltage overhead line. An extensive set of numerical simulations are provided in order to highlight the critical points of this particular application scenario, especially those that concern the modeling of both the TDR signal injection strategy and the required high-voltage coupling devices, and to plan a measurement activity. The modeling and simulation approach followed for the study of either the overhead line or the on-line TDR system is fully detailed, discussing three main strategies. Furthermore, some measurement data that were used to characterize the specific coupling device selected for this application at high frequency—that is, a capacitive voltage transformer (CVT)—are presented and discussed too. This work sets the basic concepts underlying the implementation of an on-line remote monitoring system based on reflectometric principles for in-service lines, showing how much impact is introduced by the high-voltage coupling strategy on the amplitude of the detected reflected voltage waves (also named “voltage echoes”).


2013 ◽  
Vol 183 (1) ◽  
pp. 32-38
Author(s):  
Jun Izutsu ◽  
Satoru Nagata ◽  
Tadayuki Wada ◽  
Masahito Shimizu ◽  
Kenji Ohta

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