Chain Fault Research Articles

Research on new distributed distribution network hidden fault remote automatic recovery technology

Abstract To solve a series of chain reactions in which a fault in the distribution network triggers the shutdown of other components, a new distributed distribution network hidden fault remote automatic recovery technology research is proposed. The traditional chain fault model about line protection describes that when a fault occurs on one or some lines of the system, the line protection devices will operate with a certain probability, and the misoperation or inappropriate action of these line protection devices will lead to the expansion of the fault and ultimately form a wide range of power outages. This study quantitatively gives the interaction relationship between the components in the system. Firstly, the difference between the distribution network chained fault and the main network chained fault mechanism is analyzed; secondly, the topology of the distribution network is modeled; then, the fault transfer model of the distribution network and the chained fault model based on the line dynamics model are constructed based on this model; finally, the detailed distribution network chained fault algorithm process is given based on the proposed model.

Analysis of interlocking faults and reliability evaluation methods for communication networks of power information physical systems

The information physics system realizes the integration and interaction between them by the 3C technique. The application of scheduling automation, Substation Automation and Online Fault Recovery Technology Improves Emergency Response Capability, and Information Security issues are also embedded in the energy system. Power grid operation is facing more threats, and state space and failure scenarios are also more abundant, which poses new research needs and challenges for power system stability assessment. First, the physical interaction of information is analyzed. From the perspective of function, the CPPS hierarchy corresponds to the physical Electric power system, the information sub-station system and the main station system respectively. Then, taking the information node as the fault detection sample point, the chain fault model of the power information physical system is studied, and the abnormal response of the power information system is classified and identified, Finally, a failure response model and a failure recovery model are built. Finally, a simulation example is given for verification.

An Application of Softsign Function (SF) Filter to Low-Latitude Aeromagnetic Data of Tafawa-Balewa Area, Northern Nigeria for Geostructural Mapping and Tectonic Analysis

A recently proposed edge detection technique – Softsign Function (SF) filter was applied to a synthetic magnetic data to illustrate its application. It was then applied in combination with 3D Euler deconvolution and 2D magnetic modelling techniques to the low-latitude aeromagnetic data of Tafawa-Balewa Area, Northern Nigeria, aimed at subsurface geostructural mapping and tectonic analysis of the study area. This was corroborated with mapping and analysis of surface lineaments from Landsat-9 image of the study area. The SF filter depicted edges of magnetic sources from the synthetic magnetic and aeromagnetic data as distinct peaks. The 3D Euler deconvolution solutions and 2D magnetic model showed two dominant depth ranges ∼ 10 m to ∼ 400 m (D1) and ∼ 400 m to ∼ 1000 m (D2) of magnetic sources. The subsurface and surface lineaments from the aeromagnetic data and Landsat-9 image, respectively, fairly agreed in location, trends, even distribution, and density. The trends of mapped lineaments are majorly ENE – WSW direction, and the minor trends are WNW – ESE, NE – SW, NNW – SSE, NNE – SSW, and NW – SE directions. These linear structures, consistent with regional tectonics, are suspected to be strike-slip faults generated by the conjugate system of strike-slip NE – SW and NW – SE faults, including the Romanche and Chain fault systems, produced by the oceanic-continental transcurrent movements which affected the Nigerian basement complex. Explicitly, Softsign Function (SF) filter is a valuable edge detection technique in mapping geological structures from a real low-latitude aeromagnetic data reduced to the geomagnetic equator for tectonic analysis.

Identification of Critical Nodes and Accident Chains of Power Systems under the Effect of Geomagnetic Storms

Geomagnetically induced currents (GICs) generated by geomagnetic disturbances (GMD) during strong magnetic storms may trigger chain failures in power systems. In this paper, a critical node identification method based on the improved LeaderRank algorithm considering the effects of geomagnetic storms is proposed. A chain fault identification process based on the fragility theory of complex systems is proposed to determine the initial fault line by critical nodes and simulate the fault development process to obtain the accident chain set. The effectiveness of the method is verified by using the IEEE RTS79 node system as an example. The research results show that the method can reflect the critical nodes and accident chain set of power systems under different geomagnetic storm effects, and the research results can provide a reference for geomagnetic storm disaster quantification, assessment, and prevention.

Research on Chain Fault Prevention Model Considering Voltage Stability

In this paper, we aim to prevent and control the chain tripping phenomenon in the pre-chain fault stage of the power grid, and use the L index and node injection power as the safety index to indicate the voltage stability of the power grid and the safety level of the current operation state of the power grid by adjusting the power output of the generating units. Based on this index and considering the various constraints of the grid, a preventive model is given to make the grid have the highest possible safety level against chain tripping and at the same time improve the voltage stability. In this paper, the prevention model is established based on the particle swarm algorithm, and the simulation results prove the feasibility and effectiveness of the proposed prevention model on the IEEE39 node system.

Fault Diagnosis Approach of Main Drive Chain in Wind Turbine Based on Data Fusion

The construction and operation of wind turbines have become an important part of the development of smart cities. However, the fault of the main drive chain often causes the outage of wind turbines, which has a serious impact on the normal operation of wind turbines in smart cities. In order to overcome the shortcomings of the commonly used main drive chain fault diagnosis method that only uses a single data source, a fault feature extraction and fault diagnosis approach based on data source fusion is proposed. By fusing two data sources, the supervisory control and data acquisition (SCADA) real-time monitoring system data and the main drive chain vibration monitoring data, the fault features of the main drive chain are jointly extracted, and an intelligent fault diagnosis model for the main drive chain in wind turbine based on data fusion is established. The diagnosis results of actual cases certify that the fault diagnosis model based on the fusion of two data sources is able to locate faults of the main drive chain in the wind turbine accurately and provide solid technical support for the high-efficient operation and maintenance of wind turbines.

Research on risk assessment method of distribution network based on information physical fusion

With the improvement of information level, the information attack will cross the boundary of power grid information space and cause the disturbance of power grid physical system, which will form a cross-space chain fault and affect the safe operation of power grid. Based on this, this paper proposes a distribution network node risk assessment method based on information physical fusion. Firstly, the overall structure of the distribution network and the information physical coupling characteristics of the information physical fusion are studied. Then, the cross-space chain failure scenario of distribution network with information physical fusion is analyzed. Based on this, the risk assessment method is proposed. Finally, the effectiveness of the method is verified by a numerical example.

Birnbaum importance analysis of supply chain fault risks based on binary decision diagram

Abstract The paper proposed an analytical method to facilitate the calculation of Birnbaum importance for supply chain fault risks based on binary decision diagram (BDD). First, the fault risks of supply chain are discussed. Then, taking the supply chain fault risks as an example, the modelling method of BDD based on fault tree analysis (FTA) is introduced. Third, the probability of risk is calculated through BDD, and the Birnbaum importance analysis method based on BDD is proposed. Finally, according to the FTA of a supply chain fault risks, a case study is implemented to demonstrate the BDD modelling and Birnbaum importance calculation process. The results show that BDD provide a convenient framework to evaluate the Birnbaum importance of each risk in supply chain, which is used to identify weaknesses, reduce risks and cost.

A Backup and Recovery Mechanism for Security Service Chain Fault in Network Function Virtualization Environment

A Backup and Recovery Mechanism for Security Service Chain Fault in Network Function Virtualization Environment

Ground deformation and fault modeling of the 2016 sequence (24 Aug. – 30 Oct.) in central Apennines (Central Italy)

A chain fault reactivation took place in central Apennines, from August 24 to October 30, 2016, producing five moderate-to-strong earthquakes ranging from Mw5.5 to Mw6.6. This paper presents the results from the study of the ground co-seismic ruptures around the Monte Vettore and Vettoretto, and Norcia. Surface co-seismic ruptures, were observed in the Vettore and Vettoretto segment of the fault for some kilometers (~7 km) in the August earthquakes, which were partly re-activated and expanded northward during the October earthquakes. Ruptures with 5-15 cm displacements are observed both in scree and weathered mantle (elluvium) and the bedrock, mainly fragmented carbonate rocks with small tectonic surfaces. After the October seismic sequence the co-seismic displacement doubled and reached more than 50cm. Oblique low-altitude aerial images were acquired at several sites using a UAV and 3D models were constructed using photogrammetric extrapolation. Numerous observed and mapped rock falls, slides of earth-materials etc, occur mainly along the mountain roads, on artificial slopes. They were studied with preliminary mapping from satellite imagery, and examples are presented of large landslides in the epicentral region with pre and after- the earthquake images. The first four events are associated with four individual fault segments respectively, all aligned along the mountain-fronts of Mt Gorzano and Mt Vettore. The last fifth and strongest event was the result of linkage and breaching of the previous fault segments. We modelled the fault segments intofive seismogenic sources in order to calculate the post-sequence static stress changes produced by the five seismogenic sources (or source faults) to the surrounding faults (receiver faults). Our results suggest possible triggering effects for neighbouring faults located along the strike of the source faults and delay effects for faults which are directly located either on the footwall or hanging-wall.

Generation of Transparent-Scan Sequences for Diagnosis of Scan Chain Faults

Diagnosis of scan chain faults is important for yield learning and improvement. Procedures that generate tests for diagnosis of scan chain faults produce scan-based tests with one or more functional capture cycles between a scan-in and a scan-out operation. The approach to test generation referred to as transparent-scan has several advantages in this context. (1) It allows functional capture cycles and scan shift cycles to be interleaved arbitrarily. This increases the flexibility to assign to the scan cells values that are needed for diagnosis. (2) Test generation under transparent-scan considers a circuit model where the scan logic is included explicitly. Consequently, the test generation procedure takes into consideration the full effect of a scan chain fault. It thus produces accurate tests. (3) For the same reason, it can also target faults inside the scan logic. (4) Transparent-scan results in compact test sequences. Compaction is important because of the large volumes of fail data that scan chain faults create. The cost of transparent-scan is that it requires simulation procedures for sequential circuits, and that arbitrary sequences would be applicable to the scan select input. Motivated by the advantages of transparent-scan, and the importance of diagnosing scan chain faults, this article describes a procedure for generating transparent-scan sequences for diagnosis of scan chain faults. The procedure is also applied to produce transparent-scan sequences for diagnosis of faults inside the scan logic.

Calculation of delivery rate in fault‐tolerant network‐on‐chips

Reliability for network-on-chips has been widely researched in last decades not only to support the rapid growing requirement of on-chip communication but also to address the challenge on reliability due to aggressive technology scaling. Simulation is the most common method to evaluate the capacity of reliability design but its cost is significant. Therefore, it is necessary to calculate the capacity for reliability of a design with light-weight mathematic models. A model for faults on links is described to calculate the delivery rate of networks based on a Markov chain fault model, fault-tolerant configuration and network traffic. The calculation results show accurate approximation of simulation results.

Geophysical mapping of the inland extension of Deep Ocean Fault zones, south-western Nigeria

Research activities close to the south western edge of the coastal line has shown inland extension of deep oceanic features identified as regional fault zones. This research work focused on mapping of inland extension of Chain Fault zones into the south-western part of Nigeria using both satellite images and aeromagnetic intensity map over a 55 km by 55 km Ifon Basement-Sedimentary area. The area is a transition zone between the south-western basement complex and sedimentary basin of the south-western Nigeria. Interpretations of magnetic field over the area revealed intra-sedimentary features identified as fault zone which form an alignment and inland extension pattern with the offshore Chain fault zone. On the account of the qualitative and quantitative interpretation of the acquired aeromagnetic data, the Landsat-ETM+ multi-spectral bands and Digital Elevation Model (DEM) of the topography of the area, the evidence of inter-sedimentary tectonic events are recorded in the geomorphic characteristics of the study area’s terrain in relation to the underlying influence of geology and structural trends revealed by extracted lineaments. From geophysical and geomorphologic interpretations, the observed geomorphic characteristics show three physiographical areas: the northern uplifted block (connection of a series of hills cut by deep-sided valleys), the central SW-NE trending subsided block (or graben) and the southern uplifted block. This geomorphic pattern of a series of flat and highly undulating terrain broken by a series of deep valleys and hills is believed to be related to rifting arising from the influence of the transform fault zones, which subdivide the area into smaller units. The rift valleys in the area are long, deep valleys bounded by parallel faults, or fractures. In addition, the predominant SW/NE, SE/NW and E-W trending linear structures mapped as fracture/faults cut the basement and penetrated the overlying Cretaceous and Tertiary sediments in the study area. Key word: Chain Fault zones, transform faults, rifting, inter-sedimentary tectonics, south-western Nigeria Embayment.

Utilizing Circuit Structure for Scan Chain Diagnosis

Scan chain diagnosis has become a critical issue to yield loss in modern technology. In this paper, we present a scan chain partitioning algorithm and a scan chain reordering algorithm to improve scan chain fault diagnosis resolution. In our scan chain partition algorithm, we take into consideration not only logic dependency but also the controllability between scan flip-flops. After the partition step, the ordering of scan cells is performed to decrease the range of suspect faulty scan cells by a bipartite matching reordering algorithm. The experimental results show that our method can reduce the number of suspect scan cells from 378-31 to at most 3 for most cases of ITC'99 benchmarks.

On Diagnosis of Timing Failures in Scan Architecture

Excessive test mode power-ground noise in nanometer scale chips causes large delay uncertainties in scan chains, resulting in a highly elevated rate of timing failures. The hybrid timing violation types in scan chains, compounded by their possibly intermittent manifestations, invalidate the conventional assumptions in scan chain fault behavior, significantly increasing the ambiguity and difficulty in diagnosis. In this paper, we propose a novel methodology to identify the root cause of scan chain timing failures. The proposed work addresses the challenge of diagnosing multiple permanent or intermittent timing faults in scan chains and the associated clock trees, which closely approximate the realistic failure mechanisms observed in silicon. Instead of relying on fault simulation that is incapable of approximating the intermittent fault manifestation, the proposed technique characterizes the impact of timing faults by analyzing the phase movement of scan patterns. Extracting fault-sensitive statistical features of phase movement information provides strong signals for the precise identification of fault locations and types. The manifestation probability of each fault is furthermore computed through a mathematical transformation framework which accurately models the behavior of multiple faults as a Markov chain. The identification of failing scan cells enables a further examination of the possible delay defects in the scan clock buffers, which ascertains the possible root causes of the observed scan chain failures. The proposed scheme characterizes the timing impact of the defective clock buffers by extracting the change in the delay distribution of the clock paths, enabling the effective pruning of unrealistic fault hypotheses that would result in highly deviant timing behavior. Simulation results have confirmed that the proposed methodology can yield highly accurate diagnosis results for complex fault manifestations.

Structural Reduction Techniques for Logic-Chain Bridging Fault Diagnosis

This paper proposes four logic-chain bridging fault models, which involve one net in the combinational logic and the other net in the scan chain. Test results of logic-chain bridging faults, unlike existing scan chain fault models, depend on the previous scan inputs as well as primary inputs. A bridging pair extraction algorithm is proposed to quickly extract bridging pairs from the layout. The paper proposed two sets of structural reduction techniques so that runtime is very short. Experimental results on ISCAS benchmark circuits show that, on the average, logic-chain bridging faults can be diagnosed within an accuracy of four bridging pairs. The techniques are still applicable when there are only 10 failing patterns due to limited ATE failure memory. This paper demonstrates the feasibility to diagnose logic-chain bridging faults by software.

A New Scan Chain Fault Simulation for Scan Chain Diagnosis

In this paper, we propose a new symbolic simulation for scan chain diagnosis to solve the diagnosis resolution problem. The proposed scan chain fault simulation, called the SF-simulation, is able to analyze the effects caused by faulty scan cells in good scan chains. A new scan chain fault simulation is performed with a modified logic ATPG pattern. In this simulation, we consider the effect of errors caused by scan shifting in the faulty scan chain. Therefore, for scan chain diagnosis, we use the faulty information in good scan chains which are not contaminated by the faults while unloading scan out responses. The SF-simulation can tighten the size of the candidate list and achieve a high diagnosis resolution by analyzing fault effects of good scan chains, which are ignored by most previous works. Experimental results demonstrate the effectiveness of the proposed method.