Electromagnetic time reversal (EMTR) has emerged as a promising technique to locate disturbances in power grids, thanks its location accuracy and robustness against parameters uncertainties. Furthermore, reflective medium, like the one of network, it been shown that method requires no more than single observation point. In this paper, we present an experimental validation EMTR real networks. The is performed on full-scale unenergized 677-m-long, double-circuit 10-kV overhead distribution...

In this paper, we present the development of a nanosecond pulse generator utilizing semiconductor opening switches (SOS), designed to deliver high voltage and operate at repetitive frequency. The comprises three main components: primary charging unit, magnetic compression an SOS magnification unit. To ensure stable operation high-power unit frequencies, rectifying resonant energy recovery circuit are implemented, providing 1 kV 3 kHz repetition rate. three-stage is reduce width from tens...

This paper investigates the use of norm criteria in electromagnetic time reversal (EMTR) technique to locate faults transmission lines. The energy root criterion and amplitude peak criterion, derived from 2-norm ∞-norm, are considered discussed contrastively. It is shown that both can effectively be used an EMTR method faults. ∞-norm originates temporal spatial variation quantity voltage/current wave propagation process. proven makes refocusing property waves propagating along In extremely...

In order to improve the operating bandwidth and achieve a compact design of combined antenna, Klopfenstein impedance taper method is adopted implement structure antenna in this paper. The effects with different parameters are compared analyzed simulation method. Also, quantity magnetic moment optimized low-frequency performance. relationship between performance structural for concluded based on research results. Finally, an length 30 cm designed measured. [voltage standing wave ratio (VSWR)...

Acquired partial discharge (PD) signals are always affected by various noises in the process of propagation and detection. These errors have great impact on accuracy location PD source. In this study, a new algorithm based time difference an energy accumulation curve multiple is proposed to solve problem. First, from different paths eliminated correlation shift. Then, averaged signal used calculate accumulated curves. By searching maximum those curves, differences calculated locate sources....

Recently published papers have proved the effectiveness of electromagnetic time reversal (EMTR) in locating position faults such as phase-to-ground shunt connections power grids. EMTR directly transposes idea focusing energy back to its source introduced original time-reversal (TR) methods. The current interpretation EMTR, based on metrics measuring or peak-amplitude focusing, is shown suffer from ambiguities that increase risk inaccurate fault location. After pointing out under what...

Abstract Lightning strikes to a substation happen frequently, which has serious impact on the safety of power system. Therefore, it is important evaluate effect direct lightning for sake protection. However, since propagation and attachment leader typical random process, hard sufficiently represent by some deterministic models. In order take into consideration randomness in this paper, three dimensional fractal model that reproduces tortuosity branching natural established. The proposed then...

This paper develops a fully automatic tool for the denoising of partial discharge (PD) signals occurring in electrical power networks and recorded on-site measurements. The proposed method is based on spectral decomposition PD measured signal via joint application short-time Fourier transform singular value decomposition. estimated noiseless reconstructed clever selection dominant contributions, which allows us to filter out different spurious components, including white noise discrete...

Lightning electromagnetic fields can couple to overhead power transmission and distribution lines, causing serious effects the system. that lines have a nonuniform along line conductors. Therefore, ensure accuracy of numerical calculation results, large number discretization points are needed line, which might dramatically increase computation time since evaluation lightning in presence lossy soil involves, general, Sommerfeld integrals, or, even case perfectly conducting ground, integration...

In the synthetic test of high-voltage circuit breakers, insulation failures occur very often when breaker operates frequently. It is important to diagnose early fault in test. However, installed voltage and current sensors are designed measure low-frequency components, such as power frequency current. difficult detect high-frequency partial discharge caused by breaker's fault. The can generate a radiated electromagnetic pulse. Even weak discharge, which causes small change current, large...

A noninvasive approach for high-voltage (HV) circuit breaker (CB) diagnosis, based on the time-frequency analysis of transient electric fields (E-fields) radiated due to switching operations outside enclosure [switching E-fields (STEFs)], is presented in this paper. By use a synthetic test platform, paper measures STEFs generated by CBs working both normal and fault status analyses their primary parameters, such as amplitude, center frequency, number pulses. The correlation between different...

Nanosecond-level transient electromagnetic disturbance (TED), including very fast overvoltage caused by operation of disconnectors, high-altitude pulse, and many other transients may interfere or even damage the electrical equipment. As one main protective equipment, performance metal-oxide surge arresters (MOAs) under nanosecond-level TED should be investigated then compared with that microsecond-level TED, especially lightning impulse. Based on a testing platform containing 400-kV pulse...

This paper provides an efficient iterative solution in the frequency domain for electromagnetic pulse (EMP) radiated field coupling to multiconductor transmission lines (MTLs) based on distributed analytical representation of exciting sources and technique originated from waveform relaxation. The method consists two kinds iterations, first is that incoming EMP wave couples each conductor while effects neighboring conductors were neglected; second will be not only subject illumination wave,...

With the development of ultrahigh voltage (UHV) and extra high (EHV) electric power industry in China, gas insulated substation (GIS) is applied widely. Very fast transient overvoltage (VFTO) caused by disconnector operations GIS may damage insulation equipment due to its frequency amplitude. As one main protection equipments, behavior surge arresters has received extensive attention. In this paper, residual behavior, impedance response five different representative arrester blocks when...

A lot of work has been done for the effects evaluation electronic equipment due to high-power electromagnetic environments. The focus usually stays on whether occur or not ("1" "0") during tests. However, in addition such kind either-or effects, multilevel happen many practical cases as well. In this paper, we propose a statistical approach effects. By means multinomial regression, occurrence probabilities each level can be estimated simultaneously. Through maximum likelihood estimation...

In this paper, the combined antenna array is developed to maximize effective potential gain (Gep) within finite aperture area for high-power ultra-wideband (UWB) radiation. The idea make element as small possible, so that more elements can be arranged prescribed Gep of UWB system. On other hand, should match pulse excitation. This means in frequency domain, working band cover spectrum radiated pulse, and time critical parameters field (e.g., rise monopolar pulse) not distorted, those...

The traveling-wave Marx generator was first proposed by Carl Baum to analyze the switch-closure propagation process in fast pulsed-power systems. To improve performance of transistorized sub-nanosecond pulse generator, circuit with inter-stage transmission lines is studied. Simulations indicate that delay time and impedance [microstrip on printed board (PCB)] are main factors affecting waveform. Based it, series connection modularized circuits proposed, which has advantages adjustable...

This paper presents an alternative solution for the power-flow analysis of power systems with distributed generation provided by heterogeneous sources. The proposed simulation approach relies on a suitable interpretation network in terms nonlinear circuit phasor domain. above can be solved directly frequency-domain via combination standard tool iterative numerical scheme, providing steady-state generic distribution network. At each iteration, resulting turns out to composed two decoupled...

To investigate the high-altitude electromagnetic pulse (HEMP) immunity of electrical equipment in operation, a 10-kV transmission line (TL) experimental platform is built this paper. The conducted transient disturbance (TED) could be injected to TL with power on or off. TED produced by pulsed current injection (PCI) generator, whose rise time less than 20 ns and full width at half maximum range 500 ~ 550 short-circuit state 60 Ω resistor. On other hand, equivalently designed cross section...

To overcome the multipath interference in locating transient electromagnetic (EM) radiation sources an indoor environment, we propose a criterion that calculates correlation between back-propagated signals from observation points, to be used EM time reversal (EMTR) algorithms. The method introduced this article has three main advantages with respect classical methods use full-wave simulations and other criteria, such as maximum field strength. First, compared techniques back-propagation...

In this article, a kind of tightly coupled array (TCA) with nonuniform short-circuited branches (NSCBs) is proposed. It indicates that the introduction NSCBs fundamentally changes working principle TCA and makes it operate like an electromagnetic combined antenna. Arms elements, (SCBs), together ground plane, compose current loops, which act as magnetic dipoles, elements themselves are electric so becomes dipoles in theory. Thus, backplane effect (BSE) edge truncation (ETE), limit band TCA,...

The existing models of the Metal-Oxide arresters (MOA) have difficulty covering behavior prediction under surges with front time ranging from microseconds to nanoseconds. This brief presents an equation-based dynamic nonlinear model and its circuit implementation, which can describe MOA in a wide range frequencies amplitudes consideration piecewise nonlinearity characteristics. be easily constructed based on manufacturer's data multiplication factor table for characteristic. Two types used...