Electrical Fast Transient Burst Research Articles

The Impact of Holding Voltage of Transient Voltage Suppressor (TVS) on Signal Integrity of Microelectronics System With CMOS ICs Under System-Level ESD and EFT/Burst Tests

Transient voltage suppressor (TVS) has been widely used on the printed circuit board (PCB) to protect the microelectronics system against the system-level electrostatic discharge (ESD) and electrical fast transient/burst (EFT/B) events. However, the signal integrity of the system operations may be destroyed after the system-level ESD and EFT/B immunity test, if the TVS were designed with a holding voltage of lower than the operating voltage of the CMOS ICs equipped in the system. In this work, the signal integrity of microelectronics system protected by the TVS with different holding voltages was studied under the system-level ESD and EFT/B immunity test. By monitoring the transient voltage waveforms in the time domain during system-level ESD and EFT/B immunity test, the system malfunction has been found when the TVS is with a lower holding voltage. Therefore, the holding voltage of the TVS must be greater than the system operating voltage to maintain the signal integrity in the field applications.

Uncertainty Evaluation of the Electrical Transient Rise Time

This paper deals with the uncertainty evaluation of the rise time of one pulse of an electrical fast transient burst (EFT/B), as carried out by the National Institute of Metrology, Quality and Technology (Inmetro) of Brazil. The uncertainty sources considered in this evaluation were: the oscilloscope resolution and calibration of voltage and time scale, in the Y-and X-axes, respectively; the bandwidth of the measurement system; the oscilloscope sampling rate; and the repeatability of ten different measurements. Two sets of measurements were taken from two different oscilloscope settings: in the first one, the interpolation function was enabled, and in the other one was disabled. In both cases two components stood out for their huge relative contribution: time reading and repeatability. Considered together, these two components added up approximately 87% of the expanded uncertainty for interpolated samples, and 95% for non-interpolated samples. Also, the results indicate that the oscilloscope interpolation function, if available, must be used, as the expanded uncertainty decreases by 27%. A discussion of the uncertainty budget example in Annex C of the IEC 61000-4-4 standard is presented, concluding that, once the oscilloscope interpolation function is enabled, the other uncertainty components should be considered. The combined relative contribution of these components is larger than the relative contribution of repeatability.

Electrical Fast Transient Burst Insertion Loss Measurement Method

The methodology used to provide insertion loss curves for filter components typically employs a network analyzer or other similar apparatus. The measurement is performed using small signal levels, which typically keeps filter components away from non-linear regions. When attempting to choose an off-the-shelf filter to address susceptibility tests levels, much higher signal conditions typically exist. This letter proposes an insertion loss measurement method using the Electrical Fast Transient Burst (EFTB) wave train described in IEC 61000-4-4. By employing elements in most EMC laboratories, the time and capital investment to perform measurements is kept at a low level. Both common and differential mode insertion loss measurements are explored, noting equipment challenges discovered. A comparison of insertion loss is provided for an example common mode choke, revealing a reduction of EFTB attenuation compared to the small signal case. The EFTB insertion loss data could be provided by suppliers to assist circuit designers in component selection.

Research on the Influence of 500kV Power Engineering Materials Line Parameters to EFT/B

In this paper, the influence of 500kV power line engineering materials parameters to EFT/B is discussed. When the 500kV line isolation switch cut off no-load line, arc would generate between the disconnecting switch. This paper mainly discussed the influence that disconnecting time on the electrical fast transient burst. At the time of the current zero-crossing, if the arc gap dielectric strength is less than the arc gap recovery voltage, the arc gap will be broken-down and the arc reignites. This paper analyses the influence on EFT/B caused by different power line engineering materials parameters including the moment of arc reigniting, transformer inductance and capacitance of power line. Through this research we can effectively reduce the disconnecting time by change the power line engineering materials parameters and improve the state of EFT/B.

Study on Influence of Divided Conductor with Mechanical Properties on Operating over Voltage in Power System

This paper analyzed the influence that divided conductor to electrical fast transient burst. Divided conductor may change the magnetic field distribution around the conductor, but accordingly increased conductors electrical susceptance. The mechanism that the disconnecting switch cut off the power line when the no-load current is at peak and electric arc distinguished when the current pass zero and accordingly restraining measure is proposed. The outcome showed that the model can simulate the electrical fast transient burst in capacitive power line and makes it easy to analysis complex power system problems based on simple model. The method is proved to be correct and enforceable by validation of protective measures.

The Measurements and Countermeasures of Electromagnetic Compatibility in CNC System

Because CNC systems are usually used in industrial sites, their immunity measurements are very important, this paper introduced how to perform the measurement of electrostatic discharge immunity, surge immunity, electrical fast transient burst immunity and voltage dips and short interruptions immunity. According to experience, it is not so easy to pass the measurements, this paper detailed suitable devices or other countermeasures to solve the problems in order to pass the four measurement items mentioned above.

Analysis on conducted coupling of electrical fast transient burst in mines

Under the inflammable or explosive environment, the direct measurement methods by opening up the explosion-proof shell of electrical installations were not adopted. So, it’s impossible to have a quantitative analysis on the limit of conducted disturbance for electrical fast transient burst (EFT/B) in such dangerous environments. Transient conducted coupling model, which using EFT/B as its excitation source, can be built based on circuit and electromagnetic field theory. Furthermore, numerical analysis was performed. The results indicate that the capacitive coupling voltage is the same polarity as EFT/B, and is the main disturbance form of conducted coupling in mines. The inductive coupling voltage is reversed polarity with the capacitive coupling voltage, and both peaks appear only in the rising time of EFT/B, which increase with the rising of load resistance. Moreover, the cable coupling voltage on the side of disturbance source is higher than the one on the other side in tunnel. To reduce the common resistance can suppress the resistive coupling disturbance.

EMI Soft-Sensing and Filter Based on Wavelet Applied in Underground Monitoring System

In order to enhance Electromagnetic Compatibility (EMC) of monitoring system, the EMI distribution should be obtained. But the measurement could not be accomplished perfectly because of underground condition. A novel EMI soft-sensing method was proposed to measure the electromagnetic interference(EMI) indirectly. The wavelet time-frequency analysis was introduced to monitoring system and the EMI source could be ascertained. The startup time, duration and waveform could be detected based on the running records of underground electric equipments. The electrical fast transient/burst (EFT/B), the most outstanding interference, was studied to verify the validity of wavelet analysis. EMI filter was improved in accordance of the EMI gotten from wavelet analysis. Power port immunity was developed obviously. Therefore the EFT/B of data port was restrained markedly with wavelet filtration. Coordinative effect of EMI power and wavelet filter resulted in reduction of false alarms. Results indicate that wavelet analysis and the improved EMI filter have enhanced the EMC of monitoring substations and sensors obviously. It is concluded the wavelet analysis is of guiding significance to measure underground EMI distribution and EMC of the underground monitoring system.

Investigation of Relation between EFTB Test and RF Conductive Immunity Test Using BER and Baseband Signal

High-speed telecommunication systems are influenced by electromagnetic environments because they need a wide bandwidth to transmit signals. Immunity tests of telecommunication equipment are effective for improving its immunity to electromagnetic environments. However, immunity tests are expensive to carry out because there are several different tests. The correlation among the tests should therefore be examined in order to reduce the kinds of tests that are necessary. This paper investigates the correlation between the electrical fast transient/burst (EFTB) test and the radio frequency (RF) conductive immunity test. Imitation equipment was constructed with a balun, and a baseband signal was transmitted from the associated equipment to the imitation equipment. Then, disturbances were applied to the equipment, and the telecommunication quality was evaluated by using the bit error rate (BER). The results from the EFTB test indicated that the BER was less than <TEX>$6{\times}10^{-5}$</TEX> and the value was independent of the peak value. The results from the RF conductive immunity test indicated that the BER was affected by the longitudinal conversion loss (LCL).

Wavelet analysis method of harmonics and electromagnetic interference in coal mines

In this study we propose an analytical method based on orthogonal wavelet transforms for detecting harmonic noise and Electromagnetic Interference (EMI) from power supply systems and equipment in coal mines. The method will separate interference from signals through wavelet packet decomposition and then accomplish wavelet packet synthesis towards decomposition results after filtering, to remove harmonic noise and electromagnetic interference. Detailed simulation experiments are presented to study power harmonics and Electrical Fast Transient Burst (EFT/B) interference and to validate the effectiveness of our proposed method. The experimental results show that the proposed method, suitable for mutant and non-stationary signal detection, can accurately analyze harmonic interference and EMI in coal mines, as well as establish EMI source models and perform underground Electromagnetic Compatibility (EMC) prediction analyses.

EFT/B interference transmission model and method of anti-interference in a coal mine monitoring substation

Coal mining monitoring system has been enforcing tests for the immunity of Electromagnetic Compatibility (EMC) since 2006. However, not all monitoring substations can pass the Electrical Fast Transient/Burst (EFT/B) immunity test and the explosion-proof test simultaneously. In order to enhance EMC, the EFT/B interfere transmission model was presented at the substation power port, after the EFT/B test method was used to analyze the monitoring substation power ports. Hence, a low-pass filter was designed by using the simulation software PIPICE and an anti-jamming method was proposed by way of a parallel connection of the discharge interfere circuit and the low-pass filter. The improved complex EMI filter was made up of an interference discharge device and a filter. The dynamic equivalent circuit was proposed for the EFT/B immunity test. As a result, the monitoring substation has passed the EFT/B immunity and explosion-proof tests with the complex filter. It is concluded that the complex EMI filter has significantly enhanced the immunity of the coal mining monitoring system.

Improved wavelet analysis in enhancing Electromagnetic Campatibility of underground monitoring system in coal mine

Underground Electro Magnetic Interference (EMI) has become so serious that there were false alarms in monitoring system, which induced troubles of coal mine safety in production. In order to overcome difficulties caused by the explosion-proof enclosure of the equipments and the limitation of multiple startup and stop in transient process during EMI measurement, a novel technique was proposed to measure underground EMI distri- bution indirectly and enhance Electromagnetic Campatibility(EMC) of the monitoring sys- tem. The wavelet time-frequency analysis was introduced to underground monitoring sys- tem. Therefore, the sources, the startup time, duration and waveform of EMI could be as- certained correctly based on running records of underground electric equipments. The electrical fast transient/burst (EFT/B) was studied to verify the validity of wavelet analysis. EMI filter was improved in accordance of the EMI distribution gotten from wavelet analysis. Power port immunity was developed obviously. In addition, the method of setting wavelet thresholds was amended based upon conventional thresholds in the wavelet filter design. Therefore the EFT/B of data port was restrained markedly with the wavelet filtering. Coor- dinative effect of EMI power and wavelet filter makes false alarms of monitoring system reduce evidently. It is concluded that wavelet analysis and the improved EMI filter have enhanced the EMC of monitoring system obviously.

Improved complex filter applied in enhancing EFT/B immunity at a coal mine monitoring substation

A monitoring system is an important guarantee of safety in a production mine. However, not all monitoring substations pass the electrical fast transient/burst (EFT/B) immunity test and the explosion-proof test simultaneously. To enhance the immunity, the values of capacitance and inductance should be increased, which are actually limited by coal mine explosion-proof standards. Hence, for the first time, an active filter was applied in an electromagnetic interference (EMI) output filter. As a result, the interference within 30 MHz clearly weakened, but the frequency spectrum had a wide range. An EMI input filter and ferrite beads were adopted to restrain higher frequency interference. An output interference spectrogram of the substation was obtained with an analyzer. The results indicate that the improved complex filtering markedly help to control interference. With the support of improved complex filtering and other enhancing immunity means about I/O ports, the substation managed to pass both the EFT/B immunity test and the explosion-proof test synchronously. We conclude that improved complex filtering is of vital importance in enhancing the electromagnetic compatibility (EMC) of the coal mine monitoring system.

Electrical fast-transient test: conducted and radiated disturbance determination by a complete source modeling

Tests against electrical fast transient/burst (EFT) represent a serious threat for modern high-speed electronics: besides the conducted injection of high amplitude pulse, a strong radiated field is produced during this test. The prediction of the effects of this test during the equipment early design stage requires the equivalent circuit of the generator: the output waveform into a resistive 50-/spl Omega/ load is not sufficient to recover the complete circuit, including inductive component and parasitic elements. These are essential to predict the disturbance produced in arbitrary loads, as the equipment under test can be viewed. This paper describes how to characterize the EFT generator by means of the measurement of the output voltage and current produced in presence of known loads; moreover, a procedure to calculate the current on the equipment power cord is shown, based on the use of a circuit simulator (PSPICE). Finally, the disturbance produced on different loads and the radiated field during the test are calculated and experimentally validated.