Fault Analysis Techniques Research Articles

Pulsed Laser SEU Cross Section Measurement Using Coincidence Detectors

Pulsed laser testing is a useful technique for an accurate inspection of potential weak zones in a layout of an integrated circuit. A laser pulse can provoke a similar effect as a particle hitting with the advantage of a perfect location of the hitting point. The present work describes a general method to determine a Pulsed Laser Single Event Upset (SEU) Cross Section over digital circuits by means of counting statistics. The technique is based on a coincidence detector that counts fault events by comparing synchronous outputs of the digital circuit under test and a replica of the design running on a control FPGA. A correspondence map, previously generated by injection fault analysis techniques on the replica, establishes a one-way correspondence between output patterns and each bit flip. With this scheme, the SEU is detected dynamically just using a comparison between the running model and the circuit.

Defect-oriented testing of Josephson logic circuits and systems

In this paper, defect-oriented testing of low temperature superconducting Josephson logic systems is used as a basis for structural test generation. This requires the investigation of processing defects using defect monitors and the development of fault models. Inductive fault analysis techniques play an important role in this approach. By means of fault injection in the JSIM circuit simulator, the most effective test signals can be derived which can subsequently be used for test-generator hardware in a built-in self test environment.

Efficient dynamic synchronous machine simulation with harmonics

Within this paper, an efficient procedure for the dynamic simulation of faulted synchronous machines operating in the presence of harmonics is presented. The algorithm employs steady-state frequency domain techniques for simulation of the transmission system sequence networks and time domain methods for synchronous machines represented in the odq frame of reference. The procedure affords greater accuracy than conventional fault analysis techniques based strictly on steady-state methods, yet requires far less computational time than full system dynamic simulations such as those using the EMTP.

Four-Dimensional Evolution of a Salt-Related Fault Network: Eugene Island Block 330 Field, Offshore Louisiana: ABSTRACT

The Eugene Island Block 330 field consists of two anticlinal rollovers in the hanging wall of a listric normal fault system that detaches along a deep salt weld. We use interpretation of well and 3D seismic data, 3D structural restoration, and fault analysis techniques to investigate the evolution of the three-dimensional geometry through time and its impact on hydrocarbon migration and entrapment. The master fault that currently forms the northeastern boundary of the field originated as two distinct, overlapping fault segments separated by a relay ramp. The segments linked by breaching of the ramp prior to 2.2 Ma. The resultant footwall splay continued to accommodate a significant proportion of the net slip, but became essentially inactive by 1.5 Ma. In the hanging wall of the master fault, interaction between two synthetic splays and an antithetic fault resulted in a similar, complex history of varying displacement distribution. Analysis of evolving hanging and footwall cutoff geometries on the various faults suggests that cross-fault hydrocarbon migration at sand-on-sand contacts may have contributed to reservoir filling. This scenario requires that Lentic (>2.2 Ma) sands in the footwall were connected to deeper hydrocarbon sources, which cannot be demonstrated and may be problematic because of themore » discontinuous nature of these sands. Moreover, the present distribution of hydrocarbons and the sealing nature of faults at some sand-on-sand contacts imply that another mechanism, such as episodic vertical migration along fault zone is required to introduce hydrocarbons into the shallow reservoirs.« less

Unsynchronized two-terminal fault location estimation

A technique for power system fault location estimation which uses data from both ends of a transmission line and which does not require the data to be synchronized is described. The technique fully utilizes the advantages of digital technology and numerical relaying which are available today and can easily be applied for offline analysis. This technique allows for accurate estimation of the fault location irrespective of the fault type, fault resistance, load currents, and source impedances. Use of two-terminal data allows the algorithm to eliminate previous assumptions in fault location estimation, thus increasing the accuracy of the estimate. The described scheme does not require real-time communications, only offline post-fault analysis. The paper also presents fault analysis techniques utilizing the additional communicated information.

Thermal Fault Analysis and the Diagnostic Model Processor

Abstract Experience with a process fault analysis technique known as the Diagnostic Model Processor (DMP) is reviewed. Two examples are presented. The first example deals with the feedwater system of a nuclear power plant. The second example deals with the steam supply system of an oil refinery. Both examples were implemented with Gensym’s G2 expert system software tool and tested off-line with simulations of the processes. Though the overall impression of the technique is good, experience to date highlighted two problems with DMP. The first problem is an inability to readily detect competing multiple faults. The second problem is its failure to include temporal data or “trends” as a component of its knowledge base.

Parameter-insensitive technique for aircraft sensor fault analysis

A new method of analyzing faults in the m measurements of an nth-order system is presented. The proposed approach uses the estimation error space of each observer in a bank of observers to detect and isolate sensor faults. The designs are applied to a nonlinear model of an unmanned aircraft that has been described in previous publications. The reconfigurability of the aircraft sensor system is demonstrated, and the results show rapid recovery from a faulty sensor. The use of the observation error eliminates the need for state-space computations, thus producing an effective real-time fault monitor for fly-by-wire aircraft. N an earlier paper,1 a comparison of two techniques of instrument fault diagnosis (IFD) was made. This work is an extension of Patton and Willcox's idea of using analytical redundancy to design a match between m components of the observation error space instead of using state estimates di- rectly as discussed by Clark,3'4 Clark and Setzer,5 Frank and Keller,6 and Watanabe and Himmelblau.7 IFD in dynamic systems has received a significant amount of attention recently.211 Most methods described in the liter- ature discuss the analytical redundancy approach in prefer- ence to the use of redundant hardware. Analytical redundancy provides redundant (estimate) information from different measurements of a process, usually with observer or Kalman filter schemes. The commonly discussed state estimate solu- tion to IFD is based on the principle of generating estimates of part or all of the system state vector from subsets of the measurements, which when compared with similar estimates from other observers can be used to monitor the health of an instrument. The problem with the state estimate solution to IFD arises as the observer requires a good linear model of the process, and it must also be assumed that the disturbances on the system are well modeled or else have an insignificant effect on plant parameter variations. These limitations cause the state estimate approach to be inadequate for many real en- gineering applications. Sensitivity to input-induced parameter variations causes uncertain errors between redundant state estimate vectors, and in an IFD scheme these errors could cause false signaling of an instrument fault. It becomes clear that the bandwidth of uncertain signals should be estimated prior to the IFD system design. The use of frequency domain sensitivity information in this way enables a robust approach to the observer design to be made. The conjecture used is that the innovations or prediction error signals contain all the information concerning the parameter variations of the pro- cess being identified and controlled. Attention is thus turned toward the use of an innovations-based approach to system fault diagnosis that has wide potential applications. By using a weighting of the measurement estimation error as a parity