Low-Noise Power Delivery Network Design Using Power Transmission Line for Mixed-Signal Testing

Signal and power integrity are crucial for ensuring high performance in high speed digital systems. As the operating frequency of digital systems increases, the power and ground bounce created by simultaneous switching noise (SSN) has become a limiting factor for the performance of these devices. SSN is caused by parasitic inductance that exists in the power delivery network (PDN), and voltage fluctuations on the power and ground rails can lead to reduced noise margins and can limit the maximum frequency of a digital device. A new PDN design has been suggested that achieves significantly reduced SSN [1] by replacing the power plane structure with a power transmission line (PTL). In this paper, a new power delivery scheme is shown to significantly reduce switching noise at lower power. This concept has been demonstrated through theory, simulation, and measurements.

In this paper, a new method is proposed to estimate the simultaneous switching noise (SSN) directly from the power delivery network (PDN) frequency-domain impedance in order to reduce the time-domain simulation of SSN and computational burden, which is based on the periodic characteristics of the switching current and the SSN produced by one current pulse. The frequency-domain impedance is approximated with several single resonance circuits, which can capture the resonance characteristics of the PDN. The parameters of each resonance circuit are calculated with the rational function. It is also found that the SSN can be suppressed through adjusting the resonant frequencies and the period of switching current. Compared with the single resonance lumped circuit model and multi-resonance distributed circuit model, the performance of the new method for estimating the SSN is verified, which is more accurate than the target impedance method.

When the high-frequency signal is transmitted through parallel plane by via, it encounters discontinuities at its reference planes, where the high frequency TEM waves are not guided smoothly between signal trace and the reference plane. As a result, the electromagnetic wave energy between the signals and return currents are redistributed, and electromagnetic waves at the parallel planes cavity are excited due to the absence of continuous return current plane at the via neck. The loaded energy is a main source of PCB edge radiation, and at the same time, at resonance frequencies of the resonator formed by the package's parallel planes, the noise electromagnetic energy in parallel plane cavity, such as SSN (simultaneous switching noise), is more easily to be coupled into via too, which may cause the deterioration of the signal on the via. To thoroughly study this phenomenon, this paper makes theoretical investigation of the influence of parallel plane resonance to via's SSN coupling based on cavity resonator theory and coupling mechanism to get the theoretical support for the influence of parallel plane resonance, especially the power/ground resonant impedance to SSN coupling. Because the SSN coupling above is maximized, when the impedance of the power/ground system is maximized, the ways to mitigate the coupling should be based on reducing the impedance of avoid the impedance. Three ways to mitigate this SSN coupling including 1) adding anti-via (shorting via) near the initial via; 2) reducing overall parallel plane impedance; 3) adding capacitor the reduce the parallel plane impedance near the location of the via are investigated. Finally, the effect of the three ways above are simulated and compared with the structures without these three improvements.

The effect of a plane discontinuity on a plane wave propagated in a cylindrical tube is calculated by variational methods. In carrying out the calculations a transmission line analogy is used and the effect of the discontinuity at a distance is represented by a capacitance placed at the discontinuity. In section 1 the equations of motion for the propagation of a small disturbance in a cylindrical tube are established, culminating in the tyro-dimensional wave equation, while the solutions to the equations are discussed in section 2. These solutions constitute an infinite set of modes, in addition to the plane wave usually treated in the literature. In section 3 the analogy between propagation of sound and an electrical transmission line is established, and it is shown that each mode requires a separate transmission line. In section 4 it is shown that the effect of the higher modes excited by a plane discontinuity may be represented by a lumped capacitance, and this capacitance is given by a variational expression which gives a systematic method of calculation yielding an upper bound to the true answer. For the case of a window, a variational principle is produced inihich gives a lower bound to the true answer. In section B this method is applied to a window in a rectangular tube in some detail, in section 7 it is applied to a change of cross section in a rectangular tube, and in section 8 it is applied to windows and changes of cross section in circular tubes. In section 9 the reflection and transmission factors are calculated, and in section 10 the resonant frequency of certain types of resonators is calculated. To the authors's knowledge this is the first rigorous treatment of the above problems with the exception of an earlier paper calculating the reflection due to a change of cross section in a circular tube.

Purpose – This paper aims to reduce the worst-case crosstalk effects for resistance, inductance and capacitance (RLC) interconnects using the bus encoding technique. In current nanoscale technology, power dissipation, propagation delay and crosstalk performance of interconnects determine the overall performance of a chip. Signal integrity issues due to crosstalk in the form of voltage glitches, overshoots, undershoots, undesirable noise, propagation speed ups and downs, etc. are some of the major deterrents for high-performance RLC modelled (VLSI) interconnects. This research paper primarily proposes two novel encoding methods (I and II) for RLC modelled interconnects to reduce the effect of crosstalk, simultaneous switching noise (SSN) and power consumption. Design/methodology/approach – The proposed methods are based on the bus encoding method that is effective and well-suited for the reduction of the crosstalk noise. This method encodes or transforms incoming data in a manner that encoded data contain minimum or no crosstalk effects. The proposed encoding method uses the bus invert (BI) method. The proposed encoding methods are able to avoid the worst-case crosstalks while consuming lesser power during transmission in VLSI interconnects. Findings – It is observed that the proposed encoders reduced/eliminated the worst-case crosstalk by reducing SSN. The encoding method I also reduces Type 0 crosstalk by 100 per cent, while Type 1 crosstalk is reduced by 36.4 per cent and Type 2 is reduced by 16.8 per cent. The average simultaneous switching is reduced by 51.1 per cent. Similarly, encoding method II reduces switching activity by 10.3 per cent, whereas the coupling activity is reduced by 35.4 per cent. Furthermore, encoding method II also reduced Type 0, Type 1 and Type 2 crosstalk by 100, 36.9 and 27.1 per cent, respectively. Hence, the proposed encoding methods reduced the worst-case crosstalk completely. Research limitations/implications – In VLSI technology, the reduction in feature size and the increase in operating frequency are quite rapid. This leads to higher propagation delay, crosstalk and power dissipation through the interconnects. Most of the previously proposed encoders/decoders have turned out to be unsuitable for RLC modelled interconnects. Hence, the proposed encoder would be extremely useful for crosstalk reduction in newer operating conditions. Practical implications – The encoding method I identifies the harsh crosstalks, that is Type 0 and Type 1, in the inverted and non-inverted forms of incoming data with respect to the previous data. The data having minimum crosstalk in the inverted and non-inverted forms are only sent through the transmission line. The encoding method I also removes the worst-case crosstalk and simultaneously reduces other mild crosstalks. The removal of worst-case crosstalk improves the overall performance of the interconnect. The encoding method II identifies Type 2 crosstalk along with Type 0 and Type 1 similar to encoding method I. Furthermore, the encoding method II exhibits an improvement over method I in terms of reduction in crosstalk and power dissipation. Originality/value – This paper proposes a novel encoding method to reduce worst-case crosstalk effects that reduces SSN. The proposed encoding methods achieve their purpose of crosstalk reduction for several technology nodes.

Electrical power systems are different in their sizes because of their amount of generation power stations, substations, transmission lines and loads. Therefore, these factors may impact on short circuit levels values. Capacity of power stations and dummy transmission lines in Extra high voltage grid (400kV) of the Iraqi Electrical power grids cause high short circuit levels values such that exceed both rating of the peak and breaking capacity of switchgear equipment's. Reduction of short-circuit levels by using Fast-acting Flexible Alternating Current Transmission Systems (FACTS) types devices in power grids maintain the operation of power grids with acceptable value of short circuit levels for their electrical equipment's and preventing cascading event outages which may lead to blackouts. This paper mainly studies strategies on how to add Short Circuit Current Limiter (SCCL) device by determining its number, value and location of connection in power grids by programing with (PSS™E version 30.3 Package Program). IEEE 25-bus system is used for testing the adding series SCCL at power transmission lines method procedure. The results of adding series SCCL with power transmission lines give significant reducing short circuit levels for the stations have highest short circuit levels in order to prevent the blackouts of overall power grid.

A global analysis technique is proposed to calculate the effectiveness of decoupling capacitors on practical power delivery networks (PDN). The proposed method is based on separation of a PDN into its power transmission lines (PTL) and non-PTL sections. The PTL section consists of circuit components with the highest impact on the impedance of the specified power pin, including the pin itself, the nearest capacitor and segments of PTL on both sides of the capacitor. The rest of the PDN makes up the non-PTL section which could be composed of planar shapes, PTLs or a mixture of both. The non-PTL section is characterized as a distributed circuit, preferably using an electromagnetic (EM) simulator. The effectiveness of the capacitor is measured by the self-impedance of the pin which depends on the distance between them. The pin impedance is cast in a transcendental equation in the PTL section including the impedance of the non-PTL section. The optimal placement of the capacitor is calculated using an iterative approach. With the proposed method, the use of an EM simulation at each step of the iteration is eliminated, significantly speeding up the computation process. The proposed method is validated on real-life design cases.

Along with the rapid economic development in recent years, people's demands for electricity have also been increasing very rapidly, which makes the power industry grow very fast, however, there have also been new challenges for the safety of the grid. Due to the complexity of China's topography, many power transmission lines under construction and planning are inevitable to pass through the high-altitude areas. Due to the high altitude and low air pressure, a number of external environmental factors are quite different from these of the low-altitude areas, and all these factors have a great impact on the power transmission lines, which will bring a lot of special problems to the design and operation of the power transmission lines. This paper describes the finite element method analysis which is used to calculate the relevant parameters of power transmission lines in high-altitude areas, as well as the status quo of the research on high-voltage AC power transmission lines in high-altitude areas. By analyzing the status quo of these studies and combined with the actual terrain situations of high-altitude areas, we can provide the construction of high-voltage AC power transmission line in high-altitude areas with some valuable references, thus to ensure the safe operation of such power transmission lines.

Trip faults are obviously increased by frequent lightning strikes, and increasing lightning trip-out seriously affects a system’s stability and power supply reliability. In this paper, the reasons for high lightning trip-out rates in electric power transmission lines are analyzed in detail from three perspectives, as follows: the substandard lightning resistance level, lightning complexity at a mid-point between towers, and the complexity of first and subsequent lightning stroke conditions. Experiments and simulations demonstrate that the solid-phase gas arc-extinguishing method has a strong ability to extinguish power–frequency continuous-current arcs and to protect against first and subsequent lightning strokes. Since the time taken by gas arc-extinguishing is much less than the response time of relay protection, trip accidents caused by lightning strikes can be avoided and the trip rates of lightning strikes can be reduced using this method. The case analysis and practical operation results show that the solid-phase gas arc-extinguishing lightning protection method can reduce the lightning trip-out rate by more than 90%, completely solve the problem of high lightning trip-out rates, and significantly improve the reliability of power supply.

Simultaneous switching noise (SSN) is verified as a serious impact on the quality of power distribution and accuracy of the data acquisition system in the mixed signal circuits by modeling and simulating the single-stage output buffer at the driver side. To reduce SSN, a board-level slit-surface disturbance lattice electromagnetic bandgap structure is proposed. The corresponding 1-D equivalent transmission line model is established and lower and upper bound cutoff frequencies of the bandgap are derived. Suitable test boards are fabricated and measured to demonstrate the accuracy of the design concept. The measured SSN reduced to 65% and the signal jitter is decreased by 75% comparing with the solid power/ground plane, which proves that the isolation between the analog and the digital signals can be enhanced to improve the quality of power distribution, and provides a new method to improve precision for data acquisition and transmission in power monitoring system. The results show that the simulated, modeled, and measured results are consistent.

Aging characteristics of conductor surface of ultra-high voltage direct current (UHVDC) power transmission lines have a large influence on ground-level resultant electric field. A method to analyse the impact of the aged conductors on resultant electric field is introduced in this paper. Firstly, the surface profile and surface roughness of the new and aged conductors are measured by scanning electron microscopy and three dimensional phase shift Micro-Xam. Then, an indoor corona cage is set up to determine the roughness factor of the aged conductor. A time-domain finite volume method (FVM) is introduced to analyse the influence of aging characteristics of conductor surface on resultant electric field. Finally, the ground-level resultant electric field and ion current density of a typical ± 800kV UHVDC power transmission line are calculated and analysed. The result shows that the surface roughness factor of the aged conductor is much lower than that of the new conductor, and the groundlevel resultant electric field and ion current density are stronger than that of the new one.

With the continuous growth of electricity demand, the safety and stability of transmission lines have become increasingly important. To ensure the reliability of power supply, it is essential to promptly detect and address foreign object intrusions on transmission lines, such as tree branches, kites, and balloons. Addressing the issues where foreign objects can cause power outages and severe safety accidents, as well as the inefficiency, time consumption, and labor-intensiveness of traditional manual inspection methods, especially in large-scale power transmission lines, we propose an enhanced YOLOv8-based model for detecting foreign objects. This model incorporates the Swin Transformer, AFPN (Asymptotic Feature Pyramid Network), and a novel loss function, Focal SIoU, to improve both the accuracy and real-time detection of hazards. The integration of the Swin Transformer into the YOLOv8 backbone network significantly improves feature extraction capabilities. The AFPN enhances the multi-scale feature fusion process, effectively integrating information from different levels and improving detection accuracy, especially for small and occluded objects. The introduction of the Focal SIoU loss function optimizes the model’s training process, enhancing its ability to handle hard-to-classify samples and uncertain predictions. This method achieves efficient automatic detection of foreign objects by comprehensively utilizing multi-level feature information and optimized label matching strategies. The dataset used in this study consists of images of foreign objects on power transmission lines provided by a power supply company in Jilin, China. These images were captured by drones, offering a comprehensive view of the transmission lines and enabling the collection of detailed data on various foreign objects. Experimental results show that the improved YOLOv8 network has high accuracy and recall rates in detecting foreign objects such as balloons, kites, and bird nests, while also possessing good real-time processing capabilities.

Unmanned aerial vehicles (UAVs) have become important tools for power transmission line inspection. Cameras installed on the platforms can efficiently obtain aerial images containing information about power equipment. However, most of the existing inspection systems cannot perform automatic real-time detection of transmission line components. In this paper, an automatic transmission line inspection system incorporating UAV remote sensing with binocular visual perception technology is developed to accurately detect and locate power equipment in real time. The system consists of a UAV module, embedded industrial computer, binocular visual perception module, and control and observation module. Insulators, which are key components in power transmission lines as well as fault-prone components, are selected as the detection targets. Insulator detection and spatial localization in aerial images with cluttered backgrounds are interesting but challenging tasks for an automatic transmission line inspection system. A two-stage strategy is proposed to achieve precise identification of insulators. First, candidate insulator regions are obtained based on RGB-D saliency detection. Then, the skeleton structure of candidate insulator regions is extracted. We implement a structure search to realize the final accurate detection of insulators. On the basis of insulator detection results, we further propose a real-time object spatial localization method that combines binocular stereo vision and a global positioning system (GPS). The longitude, latitude, and height of insulators are obtained through coordinate conversion based on the UAV’s real-time flight data and equipment parameters. Experiment results in the actual inspection environment (220 kV power transmission line) show that the presented system meets the requirement of robustness and accuracy of insulator detection and spatial localization in practical engineering.

The electrical power generation industry is undergoing significant digital transformation in every aspect. One of the most important assets of this industry is the power transmission line (PTL) system. PTL system distributes electric power for residential and industrial uses. PTL requires regular inspections for early damage detection and maintenance to transmit high-voltage electric power efficiently and reliably. The detection and localization of damage across transmission equipment are crucial, as they help power transmission companies reduce maintenance expenses and prevent unexpected power outages. Traditionally, these inspections have been conducted by line crawling or with the assistance of a helicopter to plan for necessary repair or replacement works before any significant damage that could cause a power outage. These traditional solutions are slow, costly, and dangerous. The emergence of drones, high-resolution cameras, edge computing, and deep learning technology opens the opportunity for PTL inspection using drones. In this paper, the literature review is conducted as a preliminary study for our research. Moreover, the state-of-the-art of PTL technology, the general autonomous drone-based PTL inspection system, is being discussed. Finally, we summarize the research challenge and future direction of research in this field.

Impact of high-voltage power transmission lines on photovoltaic power production