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.

Simulating resistive bridging and stuck-at faults

Abstract: We present a simulator for resistive bridging and stuck-at faults In contrast to earlier work, it is based on electrical equations rather than table look-up, thus exposing more flexibility For the first time, simulation of sequential circuits is dealt with; reciprocal action of fault effects in current time frame and earlier time frames is elaborated on for different bridge resistances Experimental results are given for resistive bridging and stuck-at faults in combinational and sequential circuits Different definitions of fault coverage are listed and quantitative results with respect to all these definitions are given for the first time

An on-line expert system for fault section diagnosis in power systems

Abstract: This paper presents an expert system for diagnosis of power system fault allocation in real time (SIDUF-TR). The system uses information on the tripped relays and circuit breakers to identify the most probable faulted element of the power system, serving as a decision making support for energy control center dispatchers. First, the expert system structure is presented, including a description of the inference method used to determine the most probable failures places. Then the architecture for real-time operation of SIDUF-TR in a control center is described. Finally, the result of the application of the system to a real disturbance is presented. I. INTRODUC~ON In cases of power system disturbances, control centers dispatchers must use their judgement and experience to determine the possible faulted elements as the first step in the restoration procedures. When a breaker or its associated relays fail to operate, the fault is removed by backup protection. In such cases, the outage area is very large and it is difficult for the dispatchers to estimate the fault location. Moreover, multiple faults may eventually take place, with many breakers being tripped within a short time. In these circumstances, so many alarm messages pour into the dispatch center that it is impossible for the dispatchers to analyze the situation satisfactorily and to ensure that the most appropriate actions be taken. Therefore, it is important to develop some means of providing accurate fault analysis to assist dispatchers in these situations. This may be achieved by using an expert system, embedded in the existing energy management system (3,8). Development of expert systems for fault diagnosis of power systems has received growing attention in the last years (6,8). Some of the previously reported systems for fault diagnosis use the monitoring information-based approach (1,8). A tree structure or a tabular form are used to organize monitoring information from tripped relays and circuit breakers and its relationship to fault location. Other fault diagnosis systems use the model-

Apparatus and method for detecting and calculating ground fault resistance

Abstract: The field ground fault detector (100, 200, 500) of the present invention detects a ground fault that occurs in the field circuit and in any associated circuits galvanically connected to the field. The field ground fault detector discerns the ground resistance so that it can be monitored to detect gradual degradation of the ground resistance. The detector estimates the resistance of the ground fault and the location of the ground fault. The detector is able to estimate the location of the ground fault during system operation and during periods of non-operation. The invention utilizes a low frequency square wave oscillator (104) to permit measurement of the ground fault resistance when field voltage is not applied, to insure that there are no blind spots when the field is energized, and to provide a method for estimating the ground fault resistance. The field ground detector can differentiate between ground faults that occur on the AC side form those on the DC side of the Thyristor Bridge.

Experiments in detecting delay faults using multiple higher frequency clocks and results from neighboring die

Abstract: This paper presents experimental results from circuits specially implemented to evaluate a new technique for detecting delay faults in scan based designs. The faults are detected by observing circuit outputs at multiple capture intervals, each progressively shorter than the nominal switching delay for the logic block. For this study a simple datapath circuit was designed and fabricated through MOSIS. Extra capacitive delays were deliberately introduced in a copy of the design. The test results presented here clearly establish the signGCant potential of the proposed new delay testing approach.

Unknown input observer based detection of sensor faults in a wind turbine

Abstract: in this paper an unknown input observer is designed to detect three different sensor fault scenarios in a specified bench mark model for fault detection and accommodation of wind turbines. A subset of faults is dealt with, which are faults in the rotor and generator speed sensors as well as a converter sensor fault. The proposed scheme detects the speed sensor faults in question within the specified requirements given in the bench mark model, while the converter fault is detected but not within the required time to detect.