An automatic knowledge acquisition method for switching sequences and its evaluation

Abstract

Many e x p e r t s y s t e m s have been d e v e l o p e d f o r power s y s t e m s ' s w i t c h i n g p r o b l e m s [ 1-31 . They g e n e r a t e s w i t c h i n g s e q u e n c e s t o a c h i e v e o p e r a t i o n a l i n s t r u c t i o n s g i v e n b y human o p e r a t o r s . They u s u a l l y u s e t h e k n o w l e d g e b a s e b u i l t i n t o t h e m . T h e i r a l g o r i t h m , however, is t o o c o m p l i c a t e d t o u n d e r s t a n d by t h e u s e r s . F u r t h e r m o r e , it i s d i f f i c u l t t o e x t r a c t s u p p l e m e n t a l knowledge from human e x p e r t s , when any m a i n t e n a n c e o r e x t e n s i o n is r e q u i r e d . Consequently, t h e a l g o r i t h m o r t h e knowledge b a s e is u s u a l l y f i x e d a f t e r system d e v e lopment, w h i l e t h e power s y s t e m s c o n t i n u e t o expand. The i m p o r t a n t g o a l o f t h i s r e s e a r c h is t o d e v e l o p an i n t e l l i g e n t system f o r s w i t c h i n g sequence g e n e r a t i o n which c a n m a i n t a i n a n d e x t e n d i t s knowledge b a s e by i t s e l f . T h e r e f o r e , a n a d d i t i o n a l mechanism is needed i n t h e system t o a c q u i r e t h e knowledge a u t o m a t i c a l l y . T h i s p a p e r i n t r o d u c e s a new m e t h o d f o r t h e c o n s t r u c t i o n of knowledge b a s e by which knowledge can be e x t r a c t e d from t h e p a s t e x p e r i e n c e s of o p e r a t o r s r a t h e r d i r e c t l y from them. The knowledge b a s e is a u t o m a t i c a l l y updated e v e r y t i m e t h e human e x p e r t s i n t e r a c t w i t h t h e system. The a u t h o r s have d e v e l o p e d a new l e a r n i n g a l g o r i t h m named HCL ( H i e r a r c h i c a l C o n c e p t b a s e d L e a r n i n g ) t o r e a l i z e t h e a b o v e a p p r o a c h . HCL makes u s e o f some c o n c e p t u a l h i e r a r c h i e s f o r l e a r n i n g , f o r i n s t a n c e , t h e h i e r a r c h y of domain model t h a t e x p r e s s e s p h y s i c a l r e l at i o n s h i p s among c o m p o n e n t s , s u c h a s ' a -p a r t -o f o r ' c o n n e c t ' r e l a t i o n s . 0-7803-1301-1193SO3.00 6 1993 IEEE HCL h a s been a p p l i e d t o t h e knowledge a c q u i s i t i o n f o r ' s w i t c h i n g o p e r a t i o n knowledge' f o r e l e c t r i c power systems d u r i n g t h e normal s t a t e . HCL produces g e n e r a li z e d knowledge from o p e r a t i o n a l s e q u e n c e s made by human e x p e r t s in t h e p a s t . The a u t h o r s have e v a l u a t e d t h e l e a r n i n g performance and d i s c u s s e d some e x t e n s i o n in a modular f a s h i o n f o r i t s p r a c t i c a l u s e .F i g . 1 shows t h e a r c h i t e c t u r e o f p r o p o s e d system f o r s w i t c h i n g sequence g e n e r a t i o n . The knowledge base i s a u t o m a t i c a l l y c o n s t r u c t e d by o b t a i n i n g o p e r a t i o n a l e x p e r i e n c e s f r o m t h e u s e r s a t t h e s y s ...

A universal expert system to form switching sequence

“…Art of the state Expert system, which can integrate knowledge of field operators, has been the mainstream to generate switching sequence of substations [1][2][3]. For the first generation of this system, the algorithm or the knowledge base is usually fixed after system development, which may outgrow and redeveloped when the topology of substation changes with extension [1].…”

“…In order to infer switching sequence universally for various substations, the proposed switching sequence system adopts architecture different from that of [2] as shown in Fig.4. Also, the knowledge base of the switching sequence system is integrated fixedly as module function since the rather low complexity of the proposed expert system It can be seem from Fig.4 that the formation of switching sequence can be analyzed as following step: i.…”

A computer-aided technique for generating substation interlocking schemes

“…The module considers the operating constraints of the components and the viability of the path [14]- [17]. When multiple paths are available, the module selects the one with minimum switching operations.…”