Fault indicator

About: Fault indicator is a research topic. Over the lifetime, 10057 publications have been published within this topic receiving 143482 citations. The topic is also known as: FCI & power line fault indicator.

Digital fault location for parallel double-circuit multi-terminal transmission lines

Abstract: Two new methods are proposed for fault point location in parallel double-circuit multi-terminal transmission lines by using voltages and currents information from CCVTs and CTs at all terminal. These algorithms take advantage of the fact that the sum of currents flowing into a fault section equals the sum of the currents at all terminals. Algorithm 1 employs an impedance calculation and algorithm 2 employs the current diversion ratio method. Computer simulations are carried out and applications of the proposed methods are discussed. Both algorithms can be applied to all types of fault such as phase-to-ground and phase-to-phase faults. As one equation can be used for all types of fault, classification of fault types and selection of faulted phase are not required. Phase components of the line impedance are used directly, so compensation of unbalanced line impedance is not required.

Feature Extraction of Demagnetization Faults in Permanent-Magnet Synchronous Motors Based on Box-Counting Fractal Dimension

Abstract: This paper presents a methodology for feature extraction of a new fault indicator focused on detecting demagnetization faults in a surface-mounted permanent-magnet synchronous motors operating under nonstationary conditions. Preprocessing of transient-current signals is performed by applying Choi-Williams distribution to highlight the salient features of this demagnetization fault. In this paper, fractal dimension calculation based on the computation of the box-counting method is performed to extract the optimal features for diagnosis purposes. It must be noted that the applied feature-extraction process is autotuned, so it does not depend on the severity of the fault and is applicable to a wide range of operating conditions of the motor. The performance of the proposed system is validated experimentally. According to the obtained results, the proposed methodology is reliable and feasible for diagnosing demagnetization faults in industrial applications.

Automatic Test Generation for Stuck-Open Faults in CMOS VLSI

Abstract: Because of its relative low power dissipation, intermediate speed, and high density, CMOS (Complementary Metal Oxide Semiconductor) will emerge as one of the leading VLSI technologies. Therefore, testing CMOS VLSI circuits is very important. The conventional stuck-at fault assumptions are not sufficient for modeling some faults that are peculiar to CMOS circuitry, specifically the stuck-open faults. These faults are sequential in nature. This means that when a fault occurs in a combinational circuits, the circuit behaves as a sequential circuit. Therefore, special test pattern generation techniques are necessary to test this type of faults. In this paper, we present an algorithm which uses the conventional stuck-at list to detect some stuck-open faults. Some modifications of the conventional testing procedure are necessary. Such modifications and their associated programming effort are expected to be straight forward. For the stuck-open faults that cannot be detected by the conventional stuck-at test list, a second algorithm is described that generates the tests for such faults. The algorithm generates the test if such a test exists. If not, the fault is declared as undetectable. First, we will discuss the stuck-open fault and its peculiarity to CMOS circuitry. Second, we will describe the step-by-step algorithms used to generate a complete test list for this type of fault. Finally, a small example circuit will be used to illustrate the new test generation technique and some conclusive remarks will be given.

Method and apparatus for detecting faults in a computer network

Abstract: The present invention is for a fault detecting system for a computer network comprising a plurality of computer systems which are placed apart and interconnected by a communication network, and a central computer system monitors faults in the network. The central computer system stores fault information which is transmitted from a plurality of computer systems and judges whether the information indicates a fault occurring for a slight fault or for a serious fault based on the length of the duration of the fault, and display means performs the alarm display for a case of a serious fault and does not display for a case of a slight fault. As a result, the central computer system effectively detects faults in a computer network in which a plurality of computer systems are interconnected with the central computer system by means of a monitoring system that automatically distinguishes serious faults from slight faults.

Method of controlling a network element to aggregate alarms and faults of a communications network

Abstract: A distributed method and system of controlling a communications network having a plurality of spans of interconnected network elements some of which include a network element processor distributes network topology information to respective span databases; stores original fault objects in the respective span databases; advertises fault objects to other network element processors in a local span when the original fault affects network elements other than a network element in which the fault occurred; advertises alarm objects to other network element processors that are respectively associated with a circuit affected by the original faults; stores the advertised fault and alarm objects in the respective span databases; and performs distributed processing of the advertised fault and alarm objects with the other network element processors and the respective span databases. Aggregation of other faults and alarms that may be occurring on the communications network due to other faults other than the received fault aids in determining causality of the fault. Causality may be determined by correlating other faults and alarms with the received fault. If not a root cause of another fault or alarm, the received fault is sympathetic to another fault or alarm. Sympathetic faults are suppressed while root cause faults are promoted to an alarm and reported to affected network elements. The number of alarms viewed by a network manager as well as the reporting of alarms and underlying faults are reduced by performing such distributed alarm correlation and fault reporting suppression.