No abstract

No abstract

Hardy S e n i o r Member I n s t i t u t de r e c h e r c h e d'lydro-Qu6bec (IREQ) 1800 montse S t e -J u l i e Varennes, QuBbec, Canada JOL 2PO Abstract -Over t h e last few y e a r s , t h e problem of e x p l o s i o n s i n o i l -i n s u l a t e d equipment as a r e s u l t of low-impedance f a u l t s h a s t a k e n on i n c r e a s i n g proport i o n s , mainly because of t h e h i g h e r c u r r e n t l e v e l s now a v a i l a b l e and t h e aging of t h e equipment.The problem may become c r i t i c a l when t h e e x p l o s i o n is n o t confined t o t h e t a n k and sends o i l o r p r o j e c t i l e s f l y i n g i n t o t h e environment, j e o p a r d i z i n g t h e s a f e t y of surrounding equipment. T h i s paper p r e s e n t s two methods f o r a n a l y z i n g t h e dynamic response of e l e c t r i c a l equipment t a n k s comp l e t e l y f i l l e d w i t h o i l under f a u l t c o n d i t i o n s l i a b l e t o c a u s e e x p l o s i o n s . Both methods s i m u l a t e t h e same i n f i n i t e c y l i n d r i c a l model, s u b j e c t e d t o an e c c e n t r i c a r c , but d i f f e r e n t i r e l y in t h e i r approach. The f i r s t i s based on an a n a l y t i c a l f o r m u l a t i o n of a thin-walled s h e l l c o n t a i n i n g an i n c o m p r e s s i b l e l i q u i d ; t h e s o l u t i o n i s obtained by superposing o r t h o g o n a l components and n u m e r i c a l l y i n t e g r a t i n g t h e e q u a t i o n s of motion.The o t h e r approach i s more g e n e r a l and i n v o l v e s t h e use of t h e h i g h l y s p e c i a l i z e d s o f t w a r e PISCES, adapted f o r arc-induced e x c i t a t i o n .An u n d e r l y i n g i n t e r e s t of t h e proposed methodology i s t h a t i t can be a p p l i e d , a f t e r m o d i f i c a t i o n s , t o t h e a n a l y s i s of p a r t i a l l y f i l l e d equipment such a s d i s t r ib u t i o n t r a n s f o r m e r s .Comparison of t h e computer r e s u l t s p r o v i d e s a means of m u t u a l l y v a l i d a t i n g t h e two methods and t h u s paves t h e way f o r an extended use of PISCES t o complex models w i t h a more r e p r e s e n t a t i v e t a n k c o n f i g u r a t i o n . A few p a r a m e t r i c s t u d i e s performed with t h e a n a l y t i c a l model have pinpointed t h e c r i t i c a l f a c t o r s t o be cons i d e r e d i n t h e d e s i g n of explosion-proof t a n k s f o r e l e c t r i c a l equipment. pBgv1ouswIlRKI n c r e a s i n g concern over t h e problem of e x p l o s i o n s i n o i l -i n s u l a t e d e l e c t r i c a l equipment h a s r e s u l t e d in a s e r i e s of t h e o r e t i c a l and e x p e r i m e n t a l s t u d i e s , m o s t l y on d i s t r i b u t i o n t r a n s f o r m e r s , and f u r n i s h e d a means of i d e n t i f y i n g and u n d e r s t a n d i n g t h e fundamental mechanism t h a t may l e a d t o a c a t a s t r o p h i c f a i l u r e .In some c a s e s , approximate q u a n t i t a t i v e r e s...

No abstract

No abstract