Anti-interference techniques used for on-line partial discharge monitoring

Abstract

A b s t r a c t -To s u p p r e s s i n t e r f e r e n c e is a c r i t i c a l t e c h n i q u e of o n -l i n e p a r t i a l d i s c h a r g e monitoring f o r p o w e r e q u i pment.T h e y c a n d i v i d e i n t o t w o types: periodical and impulse i n t e r f e r e n c e according to t h e i r signal c h a r a c t e r i s t i c . T h e n d i f f e r e n t a n t i -i n t e r f e r e n c e techn i q u e s c a n be c h o s e n to s u p p r e s s t h e m s e p a r a t e l y . T h i s paper d e s c r i b e s v a r i o u s a n t i -i n t e r f e r e n c e t e c h n i q u e s w h i c h have b e e n developed recently and their actual effect for o n -l i n e partial d i s c h a r g e monitoring. T h e a b o v e techniques include c o m b i n e d f i l t e r , d i g ital f i l t e r , differential s y s t e m , p u l s e d i s c r i m i n a t i o n system. F i n a l l y t h i s p a p e r p r e s e n t s s o m e a n t i -i n t e r f e r e n c e ideas which are satisfied f o r o n -l i n e partial d i s c h a r g e m o n i t o r i n g . Key Words: o n -l i n e m o n i t o r i n g , partial d i s c h a r g e ( P D I , a n t i i n t e r f e r e n c e , t e c h n i q u e 1 . I n t r o d u c t i o n O n -l i n e P D monitoring is a n important technical m e a s u r e f o r d i s c o v e r i n g early d e f e c t o f power e q u i p m e n t and ensuring r e l i a b l e o p e r a t i o n o f power s y s t e m . Bec a u s e there are many i n t e r f e r e n c e s in the f i e l d , they will e f f e c t monitoring s e n s i t i v i t y and reliability s er i o u s l y . T h e r e f o r e o n -l i n e monitoring s e n s i t i v i t y is s m a l l e r t h a n the m e a s u ring s e n s i t i v i t y in t h e laboratory a t l e a s t t h r e e o r d e r s and s m a l l e r t h a n o-ff-line d e t e c t i n g s e n s i t i v i t y in the field a b o u t o n e o r d e r o f magnitude. So it is a c r i t i c a l t e c h n i q u e t o s u p p r e s s i n t e r f e r e n c e s f o r o n -l i n e PD m o n i t o ring. T h e main interference s o u r c e s a r e a s f o l l o w s : 1 . C o r o n a o r internal P D c o m i n g from t r a n s m i s s i o n l i n e o r o t h e r a d j a c e n t e q u i p m e n t is a n important i n t e r f e r e n c e source. T h e y almost have t h e s a m e wave-form a s P D . 2 . C a r r i e r c o m m u n i c a t i o n and h i g h frequency p r o t e c t i o n o f power system a r e a n c o n t i n u o u s periodical interference s i g n a l .

Partial Discharge Pattern Recognition of Power Transformer by Using Information Fusion

“…The characteristics of partial discharge is one of the important technical parameters for evaluating the state of power transformer insulation. Therefore, Carry on the research of this is a very good response to the latent defects of internal insulation and determine the extent of transformer inside of insulation deterioration [1] .…”

Suppression of Pulse Interference in Partial Discharge Measurement Based on Phase Correlation and Waveform Characteristics

“…In the environment with strong electromagnetic interference, a large amount of interference may be mixed into the partial discharge signals, which will influence the result of the test. These disturbances can be roughly divided into three categories: periodic interference, continuous pulse interference and white noise [2].…”