Application of Artificial Neural Networks - Digital Signal Processing in Power System Protection and Control - page 258

the training patterns too much, which is represented by the pink contour in
Fig. 12.14 . Unfortunately, its shape does not guarantee that the points from the
testing set (red circles and crosses) can be recognized correctly. Proper results of
training (although not 100% perfect) are represented by the dashed red line, which
encompasses both the blue and red circles, excluding all the cross points, thus
enabling correct classification of both training and testing cases. The knowledge
generalization feature can be assured when appropriate techniques, like random-
ization of training set elements, are applied.
12.3 ANN Applications for Power System Protection
The artificial neural networks have become popular and have been applied for
power system problems for years. This technique arouse interest of researchers
in many renowned R&D centers all around the world. Noticeable is also
interest within well known organizations (CIGRE, IEEE) and committees
(SC38 Power System Analysis and Techniques, SC39 Power System Operation
and Control, SC34 Protection) that have established task groups to investigate
possibilities of ANN application for power system problems. As a result a
number of reports have been prepared, e.g. [ 6 , 19 , 28 ], that summarize latest
achievements in the field. Cited references do not exhaust the topic completely,
since new proposals are published in journals and conference proceedings
every year.
The following (selected) examples of the ANN applications for power sys-
tem protection and control tasks are quite representative [ 5 , 7 , 11 , 18 , 21 , 24 ,
40 - 43 ]:
• Protection of transmission and distribution lines.
- Fault detection and classification,
- Fault direction discrimination,
- Adaptive distance protection,
- Distance relay for series compensated lines,
- Autoreclosing and fault location functions,
- High impedance faults detection,
- High frequency based relaying.
• Power Transformer
- Monitoring,
- Protection functions,
- Diagnostics.
• Fault location and analysis in substations.
• Other (non-protection) tasks
- On-line security assessment,
- Load forecasting,