西南石油大学学报(自然科学版)

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Hierarchical Fault Diagnosis of Rod Pumping System Based on
Fault Distinguishing

Liang Hua   

  1. College of Energy and Electrical Engineering，Hohai University，Nanjing，Jiangsu 210098，China
  • Online:2014-10-01 Published:2014-10-01

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Abstract:

There is higher fault probability under the bad work conditions of rod pumping system. Because of the large amount
of sample and the long-time steady status，this paper proposes hierarchical fault diagnosis method. Fault distinguishing and
fault identification are two phases in this method. In fault distinguishing，fault phase and normal phase are classified according
to statistical rule of normal sample in dynamometer card. Combining statistical theory and search-tree，fault identification is
processed in fault sample. Using this method，mechanical model of rod pumping system is not to be established and training
set of fault sample is not necessary. Fault distinguishing process includes：fault taring phase and fault distinguishing phase.
In fault training phase，stochastic distribution rule and parameters of samples are determined by X2 goodness-of-fit test after
abnormal samples are rejected，then normal area and fault area is calculated. In fault distinguishing phase，classification of
fault is estimated according to whether or not feature value of test sample is in fault area. Examples indicate fault samples can
be selected from large number of samples in distinguish fault and correct rate of fault distinguishing is high. Statistical rule of
training samples can reflect the actual production of oil well.

Key words: rod pumping system, fault hierarchical diagnosis, fault distinguish, surface dynamometer card, X2 Goodness-offit
test, normal area