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.

Machine Condition Prediction Based on Adaptive Neuro–Fuzzy and High-Order Particle Filtering

Abstract: Machine prognosis is a significant part of condition-based maintenance and intends to monitor and track the time evolution of a fault so that maintenance can be performed or the task can be terminated to avoid a catastrophic failure. A new prognostic method is developed in this paper using adaptive neuro-fuzzy inference systems (ANFISs) and high-order particle filtering. The ANFIS is trained via machine historical failure data. The trained ANFIS and its modeling noise constitute an mth-order hidden Markov model to describe the fault propagation process. The high-order particle filter uses this Markov model to predict the time evolution of the fault indicator in the form of a probability density function. An online update scheme is developed to adapt the Markov model to various machine dynamics quickly. The performance of the proposed method is evaluated by using the testing data from a cracked carrier plate and a faulty bearing. Results show that it outperforms classical condition predictors.

Fault Diagnosis and Tolerant Control of Single IGBT Open-Circuit Failure in Modular Multilevel Converters

Abstract: The modular multilevel converter (MMC) is distinguished by its modularity that is the use of standardized submodules (SMs). To enhance reliability and avoid unscheduled maintenance, it is desired that an MMC can remain operational without having to shut down despite some of its SMs are failed. Particularly, in this paper, complete fault diagnosis and tolerant control solution, including the fault detection, fault tolerance, fault localization, and fault reconfiguration, have been proposed to ride through the insulated gate bipolar transistor open-circuit failures. The fault detection method detects the fault by means of state observers and the knowledge of fault behaviors of MMC, without using any additional sensors. Then, the MMC is controlled in a newly proposed tolerant mode until the specific faulty SM is located by the fault localization method; thus, no overcurrent problems will happen during this time interval. After that, the located faulty SM will be bypassed while the remaining SMs are reconfigured to provide continuous operation. Throughout the fault periods, it allows the MMC to operate smoothly without obvious waveform distortion and power interruption. Finally, experimental results using a single-phase scaled-down MMC prototype with six SMs per arm show the validity and feasibility of the proposed methods.

Fault analysis on distribution feeders with distributed generators

Abstract: This paper shows that the current an inverter interfaced distributed generator (IIDG) contributes to a fault varies considerably, due mainly to fast response of its controller. This paper proposes a method to extend the conventional fault analysis methods so that IIDG contribution can be estimated in the fault analysis. The proposed method gives rms profiles of the fault currents of interest (IIDG contribution and the fault currents the protective device will see). Test results, based on a prototype feeder, show that the proposed approach can estimate the fault current's contributions under both balanced and unbalanced fault conditions.

Accurate fault location technique for power transmission lines

Abstract: The authors describe a very accurate fault location technique which uses post-fault voltage and current derived at both line ends. Fault location is independent of fault resistance and the method does not require any knowledge of source impedance. It maintains high accuracy for untransposed lines and no fault type identification is required. The authors present the theory of the technique and the results of simulation studies to determine its performance.< >

Some diagnosis methods for voltage source inverters in variable speed drives with induction machines - a survey

Abstract: Status monitoring and performance diagnosis for variable speed ac drives today is a need, more or less, depending on their application. Diagnosis can help to avoid unplanned standstill, to make possible to run an emergency operation in case of a fault or to keep the time to repair short in case of a fault. For the voltage source inverter several faults are possible. In this paper, these faults and their diagnosis are covered. Possible faults and remedial strategies are listed. It is enumerated, which faults in today's standard protection systems are diagnosed. The main faults, in general not covered in these systems, are the transistor open circuit fault and the dc bus capacitor fault. In these fields diagnosis methods are under research. Some of the various reports of research groups in this field are outlined here as a survey with respect to function and properties.