1124
IEEE Transactions on Power Delivery, Vol. 3, No. 4, October 1988
MECH&ICAL FAILURE DETECTION OF CIRCUIT BREAKERS
M. L. L a i
A.
S. Y.Park,Student Member, IEEE
G C. L i n
H. Naidu, S t u d e n t Member,
Soom
A KReinhorn
Y. H. Lee, Member, I E E E
T.T. Soong
V. Demjanenko, Member, I E E E
Li K Benenson, S e n i o r Member, I E E E
IEEE
S t a t e U n i v e r s i t y of New York a t B u f f a l o
B u f f a l o , New York 14260
and
S. E. Wright
E l e c t r i c Power Research I n s t i t u t e
Palo Alto, C a l i f o r n i a 94303
-
Abstract
The e v a l u a t i o n of t h e mechanical c o n d i t i o n
of a c i r c u i t b r e a k e r , Le, w h e t h e r t h e u n i t i s i n
normal or abnormal c o n d i t i o n , h a s been s u c c e s s f u l l y
c a r r i e d o u t t h r o u g h t h e a p p l i c a t i o n of n o n i n v a s i v e
d i a g n o s t i c s , t o g e t h e r w i t h s i g n a l p r o c e s s i n g and
Through t h e methodol ogy,
d e c i si on-making technique s
q u a n t i t a t i v e ( n u m e r i c a l ) a s s e s s m e n t of a c i r c u i t
breaker f o r any o p e r a t i n g c o n d i t i o n h a s been a c h i e v e d
In t h i s E P R I and NYSERDA p r o j e c t , t e s t s of o i l
( p r i n c i p a l l y ) and s u l f u r h e x a f l u o r i d e c i r c u i t
breakers, i n v o l v i n g o p e r a t i o n s under normal and abnorm a l c o n d i t i o n s , w e r e c a r r i e d o u t a t t h r e e manuf a c t u r e r s and a t t h e U n i v e r s i t y a t Buffalo.
In a l l
cases, t h e presence of a b n o r m a l i t i e s was detected.
INTRODUCTION
I t i s w e l l - k n o w n t h a t m a l f u n c t i o n s of a
m e c h a n i c a l n a t u r e a r e a p r i n c i p a l c a u s e of f a i l u r e s
t h a t occur d u r i n g o p e r a t i o n of a c i r c u i t breaker [ l ] .
Noninvasive d i a g n o s t i c s , through which t h e mechanical
c o n d i t i o n of a u n i t could be determined, would, then,
play a n important r o l e i n improving t h e operating
r e l i a b i l i t y of a c i r c u i t b r e a k e r .
In addition, the
s u c c e s s f u l a p p l i c a t i o n of such d i a g n o s t i c s would l e a d
t o s i g n i f i c a n t e x t e n s i o n of t h e i n t e r v a l s f o r inspect i o n and maintenance
Two m a j o r o b j e c t i v e s a r e i n c o r p o r a t e d i n t h e
p r e s e n t program
One t h r u s t i n v o l v e s t h e development
and a p p l i c a ti on of t h e d i agnost i cs--incl udi ng acqui s i t i o n of t h e v i b r a t i o n d a t a , s i g n a l p r o c e s s i n g , and
decision-making
The methodology developed l e a d s t o
t h e q u a n t i t a t i v e assessment of t h e mechanical condit i o n , thereby p e r m i t t i n g t h e d e t e r m i n a t i o n of whether
a c i r c u i t breaker i s i n normal or abnormal c o n d i t i o n
A s d e s c r i b e d i n t h e paper, t h e t e c h n i q u e s h a v e b e e n
s u c c e s s f u l l y a p p l i e d o v e r a range of a b n o r m a l i t i e s and
c i r c u i t breakers
The second p r i n c i p a l component i s a s s o c i a t e d w i t h
t h e development of a p o r t a b l e d i a g n o s t i c u n i t t h a t can
be employed i n t h e f i e l d .
The d i a g n o s t i c u n i t i s
designed t o a c q u i r e t h e t e s t d a t a of a c i r c u i t breaker
and t o carry out r a p i d l y t h e s i g n a l p r o c e s s i n g and
222-2
A paper recommended and approved
by t h e I E E E Switchgear Committee of t h e I E E E Power
Engineering S o c i e t y f o r p r e s e n t a t i o n a t t h e IEEE/
PES 1988 Winter Meeting, New York, New York,
January 31, - February 5, 1988. Manuscript submitted
August 31, 1987; made a v a i l a b l e f o r p r i n t i n g
November 17, 1987.
d e c i s i o n - m a k i n g programs. The r e s u l t s of t h i s t a s k
w i l l be i n c o r p o r a t e d i n a f o l l o w i n g paper.
E x p e r i m e n t s h a v e b e e n c o n d u c t e d upon c i r c u i t
b r e a k e r s r a t e d a t and a b o v e 1 1 5 kV.
Interrupting
media h a v e been o i l ( p r i n c i p a l l y ) and s u l f u r hexaT e s t s h a v e been c a r r i e d o u t i n
f l u o r i d e (SF 1.
manufacturers’6 l a b o r a t o r i e s , i n t h e f i e l d a t v a r i o u s
c o o p e r a t i n g e l e c t r i c u t i l i t i e s , a n d upon a u n i t
located a t the University a t Buffalo.
Test s i t e s a t
t h e manufacturer and a t t h e U n i v e r s i t y o f f e r t h e
c a p a b i l i t y of r e a d i l y i m p o s i n g a b n o r m a l i t i e s u n d e r
c o n t r o l l e d c o n d i t i o n s F i e l d d a t a were o f t e n o b t a i n e d
d u r i n g scheduled maintenance periods; h e r e the
As
d a t a b a s e was c o n s t r u c t e d and e n l a r g e d .
a n t i c i p a t e d , t h e p r e s e n c e of a b n o r m a l i t i e s d u r i n g
A l l
t e s t s i n t h e f i e l d o c c u r r e d o n a random b a s i s .
s i g n a l p r o c e s s i n g a n d d e c i s i on-making d i a g n o s t i c s
r e p o r t e d i n t h e p r e s e n t paper were c a r r i e d out a t t h e
Univer si ty
.
The test r e s u l t s h a v e demonstrated t h a t c e r t a i n
a b n o r m a l i t i e s , e g . , a d e a c t i v a t e d shock a b s o r b e r ,
yield vibration signatures that a r e readily
d i s t i n g u i s h e d f r o m t h e i r normal c o u n t e r p a r t s .
Many
(e.g.,
eroded contacts),
a b n o r m a l i t i es, however
produce changes i n s i g n a t u r e s t h a t a r e d i f f i c u l t t o
d e t e c t by o b s e r v a t i o n . Thus, t h e s i g n a l p r o c e s s i n g
a n d d e c i sion-making p r o c e d u r e s d e v e l o p e d i n t h i s
program a r e necessary i n o r d e r t o e n a b l e c o n s i s t e n t - a n d c o r r e c t - - d e t e r m i n a t i o n s of t h e m e c h a n i c a l
c o n d i t i o n of a c i r c u i t breaker.
The f o l l o w i n g s e c t i o n d e s c r i b e s t h e e x p e r i m e n t s
and t h e d i a g n o s t i c i n s t r u m e n t a t i o n S i g n a l p r o c e s s i n g
and d e c i sion-making procedures a r e then b r i e f l y
described. F i n a l l y , a p p l i c a t i o n s t o a number of t e s t
c o n f i g u r a t i o n s a t t h e manufacturer 8’ 1a borat o r i e s and
a t t h e U n i v e r s i t y a t B u f f a l o a r e presented.
A p r o j e c t of t h i s scope r e q u i r e s t h e support and
p a r t i c i p a t i o n of a b r o a d segment of t h e community.
D i r e c t p a r t i c i p a t i o n a s team members h a s i n c l u d e d t h e
e l e c t r i c u t i l i t i e s : N e w York Power A u t h o r i t y , N e w
York S t a t e E l e c t r i c and Gas Corporation, and N i a g a r a
Mohawk Power C o r p o r a t i o n
Co-operative par ti c i p a t i on
h a s i n c l u d e d m a n u f a c t u r e r s : B B C Brown B o v e r i , Inc.
(Greensburg, PA); McGraw-Edi son Power Systems, Cooper
I n d u s t r i e s (Canonsburg, PA); a n d S i e m e n s Energy a n d
Autcmation, I n c (Jackson, MS).
88 WM
TESTING
T e s t Program
V i b r a t i o n s i g n a t u r e s h a v e been acquired from
c i r c u i t b r e a k e r s h a v i n g r a t i n g s of 115 kV and a b o v e
T e s t s h a v e been conducted upon ( p r i n c i p a l l y ) o i l and
SF6 units.
The m e a s u r e m e n t s h a v e b e e n c a r r i e d o u t
0885-8977/88/1000-1724$01.00@1988 IEEE
Authorized licensed use limited to: UNIVERSITY TENAGA NASIONAL. Downloaded on March 11,2010 at 05:08:29 EST from IEEE Xplore. Restrictions apply.
1725
under f i e l d c o n d i t i o n s ( a t t h e e l e c t r i c u t i l i t i e s ) and
i n t h e l a b o r a t o r y ( a t t h e m a n u f a c t u r e r s and a t t h e
University a t Buffalo).
I n a l l cases, t h e c i r c u i t
b r e a k e r s were operated out of s e r v i c e .
The d e v e l o p m e n t of s i g n a t u r e s a n d d i a g n o s t i c
procedures was based upon comparisons of e x t e r n a l t a n k
w a l l a c c e l e r a t i o n d a t a obtained from a g i v e n c i r c u i t
b r e a k e r t h a t was o p e r a t e d u n d e r b o t h normal a n d
abnormal conditions.
Abnormal c o n d i t i o n s h a v e
i n c l u d e d d e a c t i v a t e d shock absorber s, eroded c o n t a c t s,
m i s a l i g n e d b u s h i n g s , o v e r t r a v e l s t o p misadjustment s,
broken s t a t i o n a r y c o n t a c t , and changes i n t a i l s p r i n g
settings.
Sample Data
Sample d a t a from f o u r c i r c u i t b r e a k e r s a r e
considered.
The u n i t s a r e d e s i g n a t e d h e r e i n a s :
Siemens (BZO-121; 115 kV o i l ) , General E l e c t r i c (FEK239; 115 kV o i l ) , McGraw-Edison (RHF-90; 242 kV o i l ) ,
and B B C (PA-40; 242 kV SF6).
T h e Siemens, McGrawEdison, and BBC c i r c u i t b r e a k e r s were new u n i t s ; each
was t e s t e d a t t h e f a c i l i t i e s of t h e r e s p e c t i v e
m a n u f a c t u r e r . The G e n e r a l E l e c t r i c c i r c u i t b r e a k e r
was i n s t a l l e d and t e s t e d a t t h e U n i v e r s i t y a t B u f f a l a
F i e l d t e s t s were p e r f o r m e d b e f o r e and a f t e r
s c h e d u l e d m a i n t e n a n c e o p e r a t i o n s . These t e s t s h a v e
p r o v e n u s e f u l i n t h e d e v e l o p m e n t of p r o c e d u r e s t h a t
were c o m p a t i b l e w i t h m a i n t e n a n c e o p e r a t i o n s .
AS
a n t i c i p a t e d , a b n o r m a l i t i e s i n t h e c o n d i t i o n of a u n i t
o c c u r r e d o n a random b a s i s . The v a r i o u s f i e l d t e s t s
h a v e p r o v i d e d s t a t i s t i c a l d a t a b a s e s on ( 1 ) s e a s o n a l
v a r i a b i l i t y of a c q u i r e d s i g n a t u r e s f r o m a s e l e c t e d
c i r c u i t b r e a k e r , ( 2 ) s e n s i t i v i t y of r e s p o n s e t o
changes i n t r a n s d u c e r l o c a t i o n , and (3) t h e s i m i l a r i t y
i n t h e s i g n a t u r e s of d i f f e r e n t u n i t s of a g i v e n model.
These a s p e c t s w i l l be i n c l u d e d i n a f o l l c u i n g paper.
Signal
Conditioning
Experiments conducted a t manufacturers' s i t e s and
a t the University a t B u f f a l o have permitted the
i n t r o d u c t i o n of a b n o r m a l i t i e s i n a c o n t r o l l e d manner
( i n a d d i t i o n , of c o u r s e , t o o p e r a t i o n u n d e r normal
conditions).
F u r t h e r , i n t h e d e v e l o p m e n t of t h e
d i a g n o s t i c p r o c e d u r e s , m e a s u r e m e n t s c o u l d be (and
were) o b t a i n e d re1 a t i v e l y c o n v e n i e n t l y both i n s i d e and
o u t s i d e of a u n i t .
In particular, a t the University
a t Buffalo, t h i s arrangement h a s enabled e x t e n s i v e
measurements t o be c a r r i e d o u t concerning t h e e f f e c t s
of t r a n s d u c e r placement upon (1) t h e a s s o c i a t e d capab i l i t y of d e t e c t i n g a b n o r m a l i t i e s and (2) t h e d e t a i l e d
v i b r a t i o n a l c h a r a c t e r i s t i c s of t h e t r a n s m i s s i o n path
f r o m t h e i n t e r i o r (i.e.,
the source) t o t h e e x t e r n a l
measurement l o c a t i o n s used f o r diagnostics.
Acquisition
Analysis
(GenRad 25 151
I
'
Signal
Analysis and
Decisionflaking
(DEE VAX 7 8 5 )
U'
Instrumentation
An overview of t h e i n s t r w n e n t a t i o n and a n a l y s i s
system i s presented i n Fig. 1. During both l a b o r a t o q
a n d f i e l d t e s t s , one o r more a c c e l e r o m e t e r s w e r e
mounted o n e a c h p o l e of a c i r c u i t b r e a k e r .
The a c c e l e r o m e t e r s w e r e u s u a l l y K i s t l e r Model 8 6 2 4 u n i t s
h a v i n g a n o m i n a l o p e r a t i n g r a n g e of 0 t o 500 g and 1
t o 8000 Hz.
S i g n a l s from t h e s i g n a l c o n d i t i o n i n g
a m p l i f i e r s were r e c o r d e d o n a H o n e y w e l l 5600E 28c h a n n e l FM t a p e r e c o r d e r .
T r i p and c l o s e command
s i g n a l s were r e c o r d e d s i m u l t a n e o u s l y w i t h t h e
v i b r a t i o n d a t a f o r timing p u r p o s e a
The bandwidth of
t h e a c c e l e r a t i o n d a t a was approximately 0 t o 8 kHz; a
sampling r a t e of 3 2 kHz was g e n e r a l l y u s e d
Measured
w a l l a c c e l e r a t i o n peak a m p l i t u d e s ranged from l e s s
than 10 g t o more than 1000 g, depending upon t h e type
of c i r c u i t breaker and upon t h e measurement l o c a t i o n
The a c c e l e r o m e t e r s ,
t h e r e f o r e , h a d t o be f i r m l y
mounted; a high-strength adhesive, i n combination w i t h
a r a r e e a r t h magnet, was employed.
[A s t u d mount
would h a v e been s u i t a b l e f o r t h e a p p l i c a t i o n s
discussed i n t h i s work1
The recorded d a t a were then d i g i t i z e d and s t o r e d
u s i n g a 16-channel computer-aided t e s t system (GenRad
Model 2515).
P r e l i m i n a r y examination of t h e raw d a t a
was c a r r i e d o u t u s i n g t h i s u n i t .
The u n i t was t h e n
l i n k e d t o a DEC VAX 785 minicomputer f o r which s i g n a l
p r o c e s s i n g and decision-making s o f t w a r e h a s been
developed.
I
RESEARCH
I NSTRUnENTAT ION
I
I PROTOTYPE
I DIAGNOSTIC UNIT
I
8 Accelerometers
1 - Trip and Close Signals
Fig. 1.
Instrumentation.
E x t e r n a l a c c e l e r a t i o n s i g n a l s obtained a t t h e t o p
of t h e t a n k of p o l e 3 of t h e Siemens c i r c u i t breaker,
during various t r i p operations, a r e i l l u s t r a t e d i n
Fig. 2 S p e c i f i c e v e n t s o c c u r r i n g d u r i n g o p e r a t i o n of
t h e c i r c u i t breaker a r e i d e n t i f i e d i n t h e top trace,
F i k 2a (normal condition).
' h e timing of p a r t i c u l a r
e v e n t s c a n be a s c e r t a i n e d f r o m a k n o w l e d g e of t h e
c i r c u i t breaker o p e r a t i o n o r from motion a n a l y z e r
d a t a . Changes i n t h e s i g n a t u r e s - - b e t w e e n o p e r a t i o n s
under normal c o n d i t i o n s and t h o s e h a v i n g abnorm a l i t i e s - - a r e a s s o c i a t e d w i t h d e f e c t a For example,
c h a n g e s i n t h e s i g n a t u r e d u e t o ( 1 ) a s h o r t e n i n g of
t h e t o g g l e between p o l e s 2 and 3, (2) a n overcompress i o n of t h e t a i l s p r i n g , and ( 3 ) combination of eroded
contacts, m i s a l i g n e d c o n t a c t s , and d e a c t i v a t e d shock
a b s o r b e r , can be s e e n i n Figs. 2 b, c, a n d d, r e s p e c t i v e l y . Some of t h e s e c h a n g e s ( f r o m t h e n o r m a l
s i g n a l ) a r e q u i t e obvious by even cursory examination
of t h e raw d a t a , (e.&, P i g . 2d); o t h e r c h a n g e s (Figs.
T
Authorized licensed use limited to: UNIVERSITY TENAGA NASIONAL. Downloaded on March 11,2010 at 05:08:29 EST from IEEE Xplore. Restrictions apply.
1726
2b and 2 c ) a r e more s u b t l e , r e q u i r i n g t h e s i g n a l
p r o c e s s i n g t h a t w i l l be d i s c u s s e d i n t h e f o l l o w i n g
s e c t i on.
shock a b s o r b e r ( F i g 3 c ) can be c l e a r l y s e e n from t h e
time t r a c e s of t h e w a l l a c c e l e r a t i o n The d e a c t i v a t e d
b u f f e r s p r i n g (Pig. 3 b ) , h o w e v e r , p r o d u c e s much
Thus,
s m a l l e r changes i n t h e v i b r a t i o n s i g n a t u r e
t h e r e i s c l e a r l y a need f o r s i g n a l p r o c e s s i n g i n o r d e r
t o be a b l e t o r e n d e r c o n s i s t e n t d e c i s i o n s c o n c e r n i n g
t h e mechanical c o n d i t i o n of t h e c i r c u i t breaker.
Fig. 3.
m
Fig.
2.
5
Time,
cqcir
1B
Wall acceleration signal s during t r i p
o p e r a t i o n Siemens BZO-121 c i r c u i t b r e a k e r ;
1 1 5 kV o i l . ( a ) Normal; (b) s h o r t e n e d t o g g l e ;
(c) overcompressed t a i l s p r i n g ; ( d ) combinat i o n of eroded c o n t a c t s , m i s a l i g n e d c o n t a c t s ,
1.
and d e a c t i v a t e d shock absorber.
Events:
t r i p s i g n a l , 2. m o t i o n s t a r t s , 3. c o n t a c t s
s e p a r a t e , 4. t a i l s p r i n g s e p a r a t e s from base,
5. shock a b s o r b e r i m p a c t e d
Figure 3 i l l u s t r a t e s , f o r t h e General E l e c t r i c
c i r c u i t breaker, t h e c o n t r a s t s between a d e a c t i v a t e d
o v e r t r a v e l b u f f e r s p r i n g (Fig. 3b), a d e a c t i v a t e d
s h o c k a b s o r b e r ( F i g . 3 c ) , and t h e n o r m a l c o n d i t i o n
(Fig. 3a) [ f o r t r i p o p e r a t i o n ] .
m e measurements were
o b t a i n e d a t t h e t o p of t h e t a n k of t h e p o l e uponwhich
t h e a b n o r m a l i t i e s were i n t r o d u c e d ' b e absence of t h e
W a l l a c c e l e r a t i o n s i g n a l s d u r i n g t r i p operation,
G e n e r a l E l e c t r i c FHK-239 c i r c u i t
b r e a k e r ; 1 1 5 kV o i l .
( a ) N o r m a l ; ( b ) Dea c t i v a t e d o v e r t r a v e l b u f f e r s p r i n g ; (c) Dea c t i v a t e d shock a b s o r b e r . E v e n t s :
l. t r i p
s i g n a l , 2. m o t i o n s t a r t s , 3. c o n t a c t s
s e p a r a t e , 4. s h o c k a b s o r b e r i m p a c t e d , 5.
shock a b s o r b e r s u p p o r t impacted, 6. s t o p
I n Fig. 4, a c c e l e r a t i o n s i g n a l s a r e p r e s e n t e d f o r
t h e McGraw-Edison c i r c u i t b r e a k e r .
The d a t a w e r e
o b t a i n e d , o n t h e s i d e of t h e t a n k of p o l e 2, d u r i n g
c l o s e o p e r a t i o n a The s i g n a l s f o r t h e two abnormalit i e s introduced--reduced c o n t a c t p e n e t r a t i o n (Fig. 4b)
and l o o s e c o n t a c t s ( F i g 4c)--appear v e r y s i m i l a r t o
t h o s e of t h e u n i t i n n o r m a l c o n d i t i o n ( F i g . 4a).
The
imposed a b n o r m a l i t i e s , p h y s i c a l l y r e l a t i v e l y s u b t l e i n
nature, c l e a r l y then require signal processing f o r
c o n s i s t e n t (and c o r r e c t ) d e c i sion-making.
I n Fig. 5 a r e shown two measurements r e c o r d e d on
t h e s i d e of t h e t a n k of t h e BBC c i r c u i t breaker d u r i n g
a c l o s e o p e r a t i o n . F i g u r e 5 a i l l u s t r a t e s a normal
operation
I n Fig. 5b, eroded s t a t i o n a r y c o n t a c t s had
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1727
r e p l a c e d t h e new c o n t a c t s of Fig. 5 a - - o t h e r a d j u s t m e n t s r e m a i n i n g t h e same.
The c h a n g e s i n t h e t i m e
t r a c e due t o c o n t a c t e r o s i o n i s n o t l a r g e , r e q u i r i n g
s i g n a l p r o c e s s i n g f o r d i a g n o s i s ; again, t h i s abnorm a l i t y i s considered t o be a s u b t l e change ( a t l e a s t )
f r m a v i b r a t i o n d i a g n o s t i c s point of view.
Fig. 5.
_- - r
W a l l a c c e l e r a t i o n s i g n a l s d u r i n g c l o s e operat i o n BBC PA-40 c i r c u i t breaker; 242 kV SFK
( a ) Normal; (b) Eroded c o n t a c t s
Events: 1.
c l o s e s i g n a l , 2. m o t i o n s t a r t s , 3. c o n t a c t s
t o u c h , 4. bumber i m p a c t e d , 5. stop
Feature Extractor
I
Signal
>, C l a s s i f i e r -
A
Feat ur e6
~
-
Decision
i
Reference
Featur e6
Fig. 4.
W a l l a c c e l e r a t i o n s i g n a l s d u r i n g c l o s e operation
HcGraw-Bdison RHF-90 c i r c u i t breaker;
242 kV o i l . ( a ) N o r m a l ; ( b ) Reduced cont a c t p e n e t r a t i o n ; (c) Loose c o n t a c t s .
E v e n t s : 1. c l o s e s i g n a l , 2. m o t i o n s t a r t s ,
3. i s o l a t i n g c o n t a c t s touch, 4. main c o n t a c t s
main c o n t a c t s t o u c h
touch r e s i s t o r , 5.
s t a t i o n a r y c o n t a c t s , a n d mechanism t o u c h e s
kick-off s p r i n s
SIGNAL PROCESSING MD DECISION-MAKING
Introduction
S i g n a l p r o c e s s i n g techniques, i n c o n j u n c t i o n w i t h
automatic decision-making procedures,
provide a
p a t t e r n r e c o g n i t i o n system t h a t can a u t o m a t i c a l l y
d e t e c t t h e d e f e c t s of c i r c u i t b r e a k e r s . A s shown i n
Fig. 6, a p a t t e r n r e c o g n i t i o n s y s t e m g e n e r a l l y cons i s t s of two p a r t s : a f e a t u r e e x t r a c t o r and a c l a s s i f i e r [21. The f e a t u r e e x t r a c t o r i s a s i g n a l processor
t h a t p r e s e n t s t h e s i g n a l i n a manner which e n h a n c e s
t h e d i f f e r e n c e s between normal and abnormal behavior.
' h e c l a s s i f i e r i s an automatic d e c i s i o n m a k e r .
Fig. 6.
A p a t t e r n r e c o g n i t i o n system.
S i g n a l p r o c e s s i n g t e c h n i q u e s denoted by t h e terms
m o d i f i e d s p e c t r a l (MS) a n a l y s i 6 a n d s t r u c t u r a l
m o d i f i c a t i o n (SW) a n a l y s i s a r e employed a s f e a t u r e
extractors
The modified s p e c t r a l a n a l y s i s y i e l d s a
s e t of s p e c t r a of any s i g n a l .
This technique i s
e f f e c t i v e i n e x t r a c t i n g u s e f u l i n f o r m a t i o n about t h e
s i g n a l and i s s i m p l e t o i m p l e m e n t i n t h e f r e q u e n c y
domain ( i n which power s p e c t r a a r e obtained).
Struct u r a l m o d i f i c a t i o n a n a l y s i s i s a more s o p h i s t i c a t e d
s i g n a l p r o c e s s i n g method t h a t r e q u i r e s v i b r a t i o n
s i g n a l s f r o m b o t h t h e e x t e r i o r and t h e i n t e t i o r of a
c i r c u i t b r e a k e r . I n t h i s method, t h e e f f e c t s of t h e
i n t e r v e n i n g s t r u c t u r e and i n t e r r u p t i n g medium a r e
i n c o r p o r a t e d so a s t o e n a b l e t h e d e t e r m i n a t i o n of t h e
s i g n a l t h a t i s c h a r a c t e r i s t i c of t h e i n t e r i o r source.
AS can be Been f r o m t h e p r e v i o u s l y d i s c u s s e d
data, decision-making by a human being, v i a point-byp o i n t o b s e r v a t i o n of p a i r s of s i g n a l s ( t h e n o r m a l
s i g n a l and t h e [unknown] test s i g n a l ) , i s c o s t l y and
Authorized licensed use limited to: UNIVERSITY TENAGA NASIONAL. Downloaded on March 11,2010 at 05:08:29 EST from IEEE Xplore. Restrictions apply.
1728
may be i n c o n s i s t e n t - - p a r t i c u l a r l y when d i f f e r e n c e s
between s i g n a t u r e s a r e r e l a t i v e l y small.
Through t h e
c l a s s i f i c a t i o n technique developed ( t h e i n p u t s t o t h e
c l a s s i f i e r s being the e a r l i e r noted f e a t u r e extract o r s ) , s i g n a t u r e s a t a given condition a r e characterized q u a n t i t a t i v e l y ( L a , n u m e r i c a l l y ) according t o
t h e i r mean v a l u e and s t a n d a r d d e v i a t i o n C r i t i c a l ( o r
t h r e s h o l d ) mean v a l u e s of t h e test s i g n a l s , i n r e s p e c t
t o t h e mean v a l u e s a s s o c i a t e d w i t h t h e normal signat u r e s a n d t h e s t a n d a r d d e v i a t i o n s of t h e n o r m a l and
test s i g n a t u r e s , a r e e s t a b l i s h e d i n r e l a t i o n t o a
desired, predetermined confidence l e v e l .
[In the
p r e s e n t program, t h e c o n f i d e n c e l e v e l was 97.5 p e r cent, La, t h e p r o b a b i l i t y of a c i r c u i t breaker being
d e c l a r e d a b n o r m a l when i t i s normal i s 2.5 p e r c e n t ;
under t h e s e c o n d i t i o n s , and f o r t y p i c a l a b n o r m a l i t i e s
t e s t e d , t h e p r o b a b i l i t y of t h e u n i t b e i n g d e c l a r e d
normal when i t i s abnormal i s l e s s t h a n 1 percent.]
The s e v e r a l f e a t u r e e x t r a c t o r s employed a d d r e s s
d i f f e r e n t a s p e c t s of t h e s p e c t r a o b t a i n e d .
Consequently, f o r a g i v e n o p e r a t i n g c o n d i t i o n , should
any f e a t u r e e x t r a c t o r a n d i t s a s s o c i a t e d c l a s s i f i e r
i n d i c a t e t h e threshold (or c r i t i c a l ) value t o have
been exceeded, t h e c i r c u i t breaker i s then d e c l a r e d t o
be i n abnormal c o n d i t i o n . Thus, t h e c o m b i n a t i o n of
f e a t u r e e x t r a c t o r and c l a s s i f i e r i s used t o determine
w h e t h e r a c i r c u i t b r e a k e r i s i n normal OT a b n o r m a l
condition.
I n o p e r a t i o n , a t l e a s t t h r e e MS a n a l y z e r s w e r e
used as f e a t u r e e x t r a c t o r s ; S M a n a l y z e r s were implemented whenever t h e d a t a were a v a i l a b l a Each f e a t u r e
e x t r a c t o r was connected t o a c l a s s i f i e r . Each c l a s s i f i e r s t o r e d t h e proper normal f e a t u r e s ; t h e i n p u t
f e a t u r e (of unknown c l a s s i f i c a t i o n , i n p r i n c i p l e ) was
characterized numerically i n respect t o t h e threshold
value
I n t h i s arrangement, t h e c l a s s i f i c a t i o n s
(Le,, n o r m a l l a b n o r m a l ) d e t e r m i n e d by t h e s e c l a s s i f i e r s m i g h t n o t a l l c o i n c i d e w i t h each o t h e r .
As
noted above, t h e c i r c u i t breaker was d e c l a r e d t o be i n
a n abnormal c o n d i t i o n i f a t l e a s t one of t h e c l a s s i f i e r s lo i n d i c a t e d , i.e., i f t h e d e c i s i o n r a t i o , DRn
[DRn = QAnITHn; where QAn = mean v a l u e c h a r a c t e r i z i n g
abnormality n and THn = t h r e s h o l d ( o r c r i t i c a l ) mean
v a l u e f o r abnormality n l > 1.00.
It should be noted t h a t i n t h e f i e l d (La, s i t e s
a t t h e e l e c t r i c u t i l i t i e s ) , t h e mechanical c o n d i t i o n
of a t e s t c i r c u i t breaker would g e n e r a l l y be unknown
I n t h e p r e s e n t paper, t h e mechanical c o n d i t i o n of t h e
v a r i o u s test u n i t s a t t h e m a n u f a c t u r e r s and a t t h e
U n i v e r s i t y a t B u f f a l o was known ( e i t h e r normal o r w i t h
an abnormality introduced)--so a s t o d e v e l o p and t o
demonstrate t h e methodology.
D e t a i l s of t h e s i g n a l p r o c e s s i n g and d e c i s i o n m a k i n g t e c h n i q u e s w i l l be p r e s e n t e d i n a f o l l o w i n g
paper.
McGraw-Edison (RHF-90; 242 kV o i l ) , and B B C (PA-40;
242 kV SF6). The r e s u l t s w i l l p o i n t t o t h e v a l u e of
u s i n g s e v e r a l ( a t l e a s t t h r e e ) MS a n a l y s i s c l a s s i f i e r s , t o g e t h e r w i t h t h e SM a n a l y s i s c l a s s i f i e r s .
I n t h e t a b l e s associated with t h e cases studied,
t h e f o l l o w i n g n o t a t i o n a p p l i e s : Q N i s t h e mean v a l u e
c h a r a c t e r i z i n g t h e u n i t i n normal c o n d i t i o n ; QAn i s
t h e mean v a l u e c h a r a c t e r i z i n g t h e u n i t h a v i n g abnorm a l i t y n; THn i s t h e t h r e s h o l d (OT c r i t i c a l ) v a l u e f o r
a u n i t h a v i n g abnormality n; DRn i s t h e d e c i s i o n r a t i o
(I(An/THn).
[For a g i v e n c i r c u i t breaker t e s t , a s
s t a t e d e a r l i e r , when t h e v a l u e of DRn e x c e e d s u n i t y
f o r any c l a s s i f i e r , t h e u n i t i s d e c l a r e d t o be i n a n
abnormal c o n d i t i o n . ] Further, use of t h e same MS and
S M numbers (e.&, MS 5 and S M 5 ) i n d i c a t e s t h a t t h e
same a s p e c t s of t h e s p e c t r u m a r e t r e a t e d by t h e two
analyses.
The r e s u l t s o b t a i n e d a r e b a s e d upon s i g n a l
p r o c e s s i n g and d e c i sion-making methods a s s o c i a t e d w i t h
a c c e l e r a t i o n s i g n a l s s i m i l a r t o t h o s e s h w n i n FigR
2-5.
Siemens [BZO-121:
Case 1.
115 kV O i l ]
T a b l e 1 i l l u s t r a t e s t h e r e s u l t s of t h e s i g n a l
p r o c e s s i n g and decision-making t e c h n i q u e s e m p l q e d f o r
t h e normal and imposed abnormal o p e r a t i n g c o n d i t i o n s
of t h e Siemens c i r c u i t breaker.
For t h i s case, t h r e e
s e t s of modified s p e c t r a l a n a l y s i s (PSI, MS2, and MS3)
were c a r r i e d out t o decision-making [ s t r u c t u r a l modif i c a t i o n d a t a were n o t a v a i l a b l e ] .
A l l MS a n a l y s e s
c l e a r l y and c o r r e c t l y i n d i c a t e d t h e p r e s e n c e of t h e
respective abnormalities
I n t h e c a s e of t h e m o s t
o b v i o u s l y d i s c e r n a b l e abnormality ( t h e combination of
eroded c o n t a c t s , m i s a l i g n e d c o n t a c t s , and d e a c t i v a t e d
Table 1
Siemens C i r c u i t Breaker [BZO-121; 115 kV O i l ]
[Top of Tank; T r i p O p e r a t i o n s ]
Condition
83
%
9,250
9,296
7,098
NA
TH1
Qfi
DRl
12,928
47,498
3.67
13,878
44,119
3.18
11.108
28,129
2.53
RA
NA
NA
TH2
12,190
71,336
5. a5
13,377
33,479
2.50
10,891
27,784
2.55
NA
NA
NA
12,435
101,079
a. 13
13,138
51,229
10,888
50,548
4.64
NA
NA
NA
QN
Q A2
DR2
m
QM
DR3
3.90
AS aha11 be seen, MS a n a l y s i s of e x t e r n a l v i b r a t i o n s i g n a l s , f o l l o w e d by c l a s s i f i e r s , c a n d e t e c t
a b n o r m a l i t i e s of c i r c u i t b r e a k e r s i n many, b u t n o t
a l l , Case6 The employment of S M a n a l y s i s e n a b l e s t h e
d e t e c t i o n of s u b t l e changes, which may n o t be d i s c e r n e d t h r o u g h IS a n a l y s i s of t h e e x t e r n a l s i g n a l s .
The c o m b i n a t i o n of S M a n d MS a n a l y s e s h a s , t o d a t e ,
l e d t o c o r r e c t decision-making i n a l l c a s e s t e s t e d
NOTE:
NA
DRn
QAl
QA2
QA3
RESULTS MD DISCUSSION
I n t h i s s e c t i o n , a p p l i c a t i o n s of t h e s i g n a l
p r o c e s s i n g and d e c i s i on-making tecbniques, d e s c r i b e d
i n t h e p r e v i o u s s e c t i o n , w i l l be i l l u s t r a t e d f o r t h e
f o u r c i r c u i t b r e a k e r s noted e a r l i e r : Siemens (BZO-121;
1 1 5 kV o i l ) , G e n e r a l E l e c t r i c (FHK-239; 1 1 5 kV o i l ) ,
QN
= d a t a not a v a i l a b l e
= d e c i s i o n r a t i o n = QAn/ntn
= mean v a l u e c h a r a c t e r i z i n g abnorshortened t o g g l e
mality 1
adjustment
= mean v a l u e c h a r a c t e r i z i n g abnorovercompressed t a i l s p r i n g
mality 2
= mean v a l u e c h a r a c t e r i z i n g abnorof eroded c o n t a c t 6, m i s a l i g n e d
c o n t a c t s , and d e a c t i v a t e d shock
absorber
= mean v a l u e c h a r a c t e r i z i n g t h e
normal c o n d i t i o n
-
-
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1729
s h o c k a b s o r b e r - F i g . 2d), t h e l a r g e s t d e c i s i o n
r a t i o s , QAn/THn, were o b t a i n e d - - r a n g i n g f r o m 3.90 t o
8.13.
The l e a s t d i s c e r n a b l e a b n o r m a l i t y ( s h o r t e n e d
t o g g l e adjustment
Fig. 2b) y i e l d e d d e c i s i o n r a t i o s
i n t h e r a n g e f r o m 2.53 t o 3.67.
Decision r a t i o s f o r
t h e o v e r c o m p r e s s e d t a i l s p r i n g (Fig. 2c) were i n t h e
r a n g e f r o m 2.55 t o 5.85.
-
Case 2.
General E l e c t r i c [FHK-239; 115 kV O i l ]
T h i s c a s e i l l u s t r a t e s t h e c a p a b i l i t y of t h e
methodology t o d i s t i n g u i s h s u b t l e a s w e l l a s r e a d i l y
d i s c e r n i b l e changes.
With t h e b u f f e r s p r i n g d e a c t i vated, t h e a c c e l e r a t i o n s i g n a l s (Fig. 3b) a r e seen t o
be very s i m i l a r t o t h o s e of t h e normal c o n f i g u r a t i o n
(Fig. 3a).
I n T a b l e 2, t h e d e c i s i o n r a t i o s o b t a i n e d
f o r two (MS 4 and MS 5) of t h e t h r e e modified s p e c t r a l
a n a l y s e s are g r e a t e r than u n i t y ( h a v i n g v a l u e s of 1.15
a n d 1.35, r e s p e c t i v e l y ) , t h e r e b y , a c c o r d i n g t o t h e
c r i t e r i a e s t a b l i s h e d , i n d i c a t i n g t h e u n i t t o be i n
abnormal condition.
The d e c i s i o n r a t i o f o r MS 6 i s
l e s s than unity.
Note t h a t t h e s t r u c t u r a l modificat i o n a n a l y s i s (SM 5) a l s o i n d i c a t e s t h e u n i t t o be i n
a b n o r m a l c o n d i t i o n A 1a r g e r v a 1 ue of t h e d e c i s i o n
r a t i o f o r SM 5, 2.80, i n r e s p e c t t o t h a t of MS 5 ,
1.35, i s f o u n d l l e corresponding g r e a t e r s e n s i t i v i t y
of t h e SM a n a l y s i s i s d e r i v e d t h r o u g h a r e a s o n a b l e
a c c o u n t i n g of t h e e f f e c t s of t h e s t r u c t u r e a n d
i n t e r r u p t i n g medium i n t e r v e n i n g between t h e i n t e r n a l
source and t h e e x t e r n a l l y measured s i g n a l .
i n d i c a t i n g p h y s i c a l changes of a s u b t l e n a t u r e
The
corresponding f e a t u r e extractors--three
modified
s p e c t r a l a n a l y s e s (MS 7, MS 8 , and MS 9 ) a n d t h r e e
s t r u c t u r a l m o d i f i c a t i o n a n a l y s e s (SM 7, S M 8, and SM
9)of T a b l e 3 - - a l t h o u g h s u c c e s s f u l i n d e t e c t i n g t h e
abnormalities, experienced d i f f i c u l t i e s on a n
i n d i v i d u a l basis.
For t h e c a s e of r e d u c e d c o n t a c t
p e n e t r a t i o n , only two of t h e s i x d e c i s i o n r a t i o s [MS 8
(1.08) a n d SM 8 (1.6911 i n d i c a t e d t h e u n i t t o be i n
abnormal c o n d i t i o n With l o o s e c o n t a c t s i n t r o d u c e d ,
f i v e of t h e s i x d e c i s i o n r a t i o s c o r r e c t l y i n d i c a t e d
t h e p r e s e n c e of a n a b n o r m a l i t y [MS 7 (1.071, MS 8
(1.13) a n d SM 8 (1.921, MS 9 (1.13) a n d SM 9 (1.3311.
N o t e a g a i n t h e g e n e r a l l y h i g h e r v a l u e s of t h e SM
a n a l y s e s i n r e s p e c t t o t h o s e of t h e i r MS c o u n t e r p a r t s
Tab1 e 3
McGraw-Edi son C i r c u i t Breaker [RHF-IK) ; 242 kV Oil 1
[Side of Tank; Close Operation]
Condition
QN
5,027
2,802
874
4,511
4,343
2,624
THl
Qfl
DR1
5,771
4,651
0.81
3,361
2,571
0.76
987
1,066
1.08
6,654
11,244
1.69
4,654
4,094
0.88
2,885
2,652
0.92
TH2
5,623
6,020
1.07
3,361
1,900
0.57
967
1,092
1.13
9,978
19,151
1.92
4,678
5,292
4,328
5,748
1.33
Q A2
DR2
When t h e s h o c k a b s o r b e r i s d e a c t i v a t e d , t h e a c c e l e r a t i o n s i g n a l s obtained (Fig. 3c) c l e a r l y become
s u b s t a n t i a l l y d i f f e r e n t from the normal d a t a of F i g
3a
Correspondingly, a l l d e c i s i o n r a t i o s a r e w e l l i n
e x c e s s of unity.
Tbe modified s p e c t r a l analyses--=
4, MS 5, a n d MS 6--have v a l u e s of 16.50, 1.42, a n d
19.89, r e s p e c t i v e l y ; t h a t of t h e s t r u c t u r a l modificat i o n a n a l y s i s , SM 5 i s 44.71.
The SM a n a l y s i s a g a i n
e x h i b i t s g r e a t e r s e n s i t i v i t y t h a n t h e MS a n a l y s i s -Le, SM 5 (44.71) a n d MS 5 (1.42).
Condition
SM5
-
E66
-
506
375
5,482
128
TA1
QAl
DR1
63 4
728
1.15
43 7
5 91
1.35
11,445
32,099
2.80
191
124
0.65
TH2
6 27
10,344
16.50
438
623
1.42
230
10,284
44.71
1,190
23,644
19.89
QN
Q A2
DR2
NOTE:
DRn
QAl
QA2
QN
Case 3.
= d e c i s i o n r a t i o n = QAnfTHn
= mean v a l u e c h a r a c t e r i z i n g abnor-
mality 1 - d e a c t i v a t e d b u f f e r s p r i n g
mean v a l u e c h a r a c t e r i z i n g abnormald e a c t i v a t e d shock absorber
ity 2
= mean v a l u e c h a r a c t e r i z i n g t h e normal
condi t i on
-
1.13
NOTE: DRn = d e c i s i o n r a t i o n = QAnlTHn
QAl = mean v a l u e c h a r a c t e r i z i n g abnormality 1
reduced c o n t a c t p e n e t r a t i o n
QA2 = mean v a l u e c h a r a c t e r i z i n g abnormality 2
loose contacts
Q N = mean v a l u e c h a r a c t e r i z i n g t h e normal
condition
-
BBC [PA-40; 242 kV SF6J
Case 4.
Table 2
General E l e c t r i c C i r c u i t Breaker
[FHK-239; 115 kV Oil1
[Top of Tank; T r i p Operation]
M I
SM8
MS9
SM9
= 7
SM7
- -
Here, t h e imposed abnormality on t h e BBC c i r c u i t
breaker, eroded s t a t i o n a r y contacts, again y i e l d e d
a c c e l e r a t i o n s i g n a l s (Fig. 5 b ) t h a t a p p e a r e d v e r y
s i m i l a r t o t h o s e of t h e p u f f e r u n i t i n normal c o n d i t i o n (Fig. 5 a ) - - i n d i c a t i n g , o n c e more, t h e i n t r o d u c t i o n of a s u b t l e p h y s i c a l change
The t h r e e modified
s p e c t r a l a n a l y s e s of T a b l e 4 (MS 10, MS 11, and MS 12)
and t h e s t r u c t u r a l m o d i f i c a t i o n a n a l y s i s (SM 10) a l l
c o r r e c t l y d e t e c t e d t h e p r e s e n c e of t h e a b n o r m a l i t y .
The d e c i s i o n r a t i o s w e r e g e n e r a l l y s i g n i f i c a n t l y
g r e a t e r t h a n u n i t y [MS 1 0 (1.64) a n d SM 1 0 (1.771, MS
11 (1.36), and MS 1 2 (1.6211.
Table 4
B B C C i r c u i t Breaker [PA-@; 242 kV SF6]
[Side of Tank; Close Operation]
Condition
QN
TH1
Qfl
DR1
E6 1 0
SM 10
MS 11
EIS 1 2
61 5
19
49
516
95 2
1,565
1.64
52
92
1.77
90
122
1.36
893
1,444
1.62
McGrarEdison [RHF-90 ; 242 kV O i l ]
The two a b n o r m a l i t i e s imposed o n t h e McGrawEdison c i r c u i t b r e a k e r - - r e d u c e d c o n t a c t p e n e t r a t i o n
and l o o s e c o n t a c t . 6 - - y i e l d e d a c c e l e r a t i o n s i g n a l s
( F i g s . 4 b and 4c, r e s p e c t i v e l y ) t h a t d i f f e r e d v e r y
s l i g h t l y from t h a t of t h e normal u n i t ( F i g 4a), thus
NOTE:
DRn
QAl
QN
= d e c i s i o n r a t i o n =QAn/THn
= mean v a l u e c h a r a c t e r i z i n g abnorm a l i t y 1 - eroded c o n t a c t s
= mean v a l u e c h a r a c t e r i z i n g t h e
normal c o n d i t i o n
Authorized licensed use limited to: UNIVERSITY TENAGA NASIONAL. Downloaded on March 11,2010 at 05:08:29 EST from IEEE Xplore. Restrictions apply.
1730
SUMMARY AND CONCLUSIONS
Through t h e use of n o n i n v a s i v e d i a g n o s t i c s , t h e
a s s e s s m e n t of t h e m e c h a n i c a l c o n d i t i o n of a c i r c u i t
breaker, L a , whether t h e u n i t i s i n normal o r abnormal c o n d i t i o n , h a s b e e n s u c c e s s f u l l y d e t e r m i n e d .
T e s t s were c o n d u c t e d upon o i l ( p r i n c i p a l l y ) and S F
6
c i r c u i t b r e a k e r s a t t h r e e m a n u f a c t u r e r s and a t t h e
University a t Buffalo.
Test procedures h a v e i n v o l v e d o b t a i n i n g v i b r a t i o n
s i g n a l s from transducers placed a l o n g t h e e x t e r n a l
s u r f a c e s of (and, under c e r t a i n conditions, w i t h i n t h e
i n t e r i o r o f ) a c i r c u i t breaker.
By a p p l y i n g d a t a
p r o c e s s i n g (modified s p e c t r a l a n a l y s i s and s t r u c t u r a l
m o d i f i c a t i o n a n a l y si s) and d e c i sion-making techniques,
t h e m e c h a n i c a l c o n d i t i o n of a u n i t u n d e r any g i v e n
o p e r a t i n g c o n d i t i o n (normal and w i t h v a r i o u s imposed
a b n o r m a l i t i e s ) was d e t e r m i n e d q u a n t i t a t i v e l y (i.e.,
numerically).
Based upon t h e c r i t e r i o n t h a t a
d e c i s i o n r a t i o [ t h e r a t i o of t h e m e a n v a l u e
c h a r a c t e r i z i n g t h e c i r c u i t breaker under t e s t ( u s u a l l y
w i t h a n a b n o r m a l i t y i n t r o d u c e d ) t o t h a t of a
c a l c u l a b l e t h r e s h o l d (or c r i t i c a l ) v a l u e ] g r e a t e r t h a n
u n i t y i n d i c a t e d t h e u n i t under c o n s i d e r a t i o n t o be i n
abnormal condition, t h e d i a g n o s t i c procedures successf u l l y i d e n t i f i e d t h e p r e s e n c e of a 1 1 a b n o r m a l i t i e s
imposed.
ACKN WLEEG EMIPY TS
"he r e s e a r c h was supported by t h e E l e c t r i c Power
R e s e a r c h I n s t i t u t e , R e s e a r c h P r o j e c t 2747-1, and by
t h e New York S t a t e Energy R e s e a r c h a n d D e v e l o p m e n t
Authority, Agreement No. 1859-EEED-TC-86.
The a u t h o r s a c k n o w l e d g e t h e s u p p o r t a n d e n couragement of Mr. Glenn B a t e s of t h e E l e c t r i c Power
Research I n s t i t u t e and Dr. Fred V. S t r n i s a of t h e M e w
York S t a t e Energy Research and D e v e l o p e n t Authority.
The c o n t r i b u t i o n s of Mr. G e o r g e P. Adams, M r . Howard
J. Lieberman, and M r . Raymond C. S e e b a l d of N i a g a r a
Mohawk Power Corpo-ration; Mr. John W. C h a r l t o n of New
York S t a t e E l e c t r i c and G a s C o r p o r a t i o n ; a n d M r .
R i c h a r d Cohen, M r . R i c h a r d B. Kruger, a n d Mr. S h a l o m
Z e l i n g h e r o f New Y o r k P o w e r A u t h o r i t y a r e
acknowledged.
The s u p p o r t and c o o p e r a t i o n of Mr. D a v i d S.
J o h n s o n a o d B B C Brown B o v e r i , Inc. ( G r e e n s b u r g , PA);
Mr. Gordon A. W i l son and McGrcrv-Edi son Power Systems,
Cooper I n d u s t r i e s (Canonsburg, PA); and Mr. W i l l i a m E
H a r p e r and S i e m e n s Energy and Automation, Inc.
(Jackson, IB) a r e acknowledged.
The a s s i s t a n c e of Mr. D a n i e l J. Walch and Ms.
T i n a M. Rottmann of t h e S t a t e U n i v e r s i t y of New York
a t B u f f a l o i n t h e s e t u p a n d c a r r y i n g o u t of e x p e r i ment s i s acknowledged.
REFERENCES
r11
r21
G Mama and R Michaca, '%e F i r s t I n t e r n a t i o n a l
E n q u i r y on C i r c u i t - B r e a k e r F a i l u r e s and D e f e c t s
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K. Fukunaga, " I n t r o d u c t i o n t o S t a t i s t i c a l P a t t e r n
Recognition," Academic Press, N e w York, N e w York,
1972.
D a v i d M. B e n e n s o n (SM '71) i s P r o f e s s o r and Chairman
of t h e Department of E l e c t r i c a l a n d Computer Engin e e r i n g a t t h e S t a t e U n i v e r s i t y of New York a t
Buffalo.
E a r l i e r , h e had been a f f i l i a t e d w i t h t h e
Westinghouse Research and Development Center, where h e
conducted r e s e a r c h i n a c o u s t i c s , f l u i d mechanics, and
plasma physics.
He r e c e i v e d t h e S.B. ( A e r o n a u t i c a l
Engineering) f r w t h e Massachusetts I n s t i t u t e of Techn o l o g y a n d t h e M.S. a n d PhD. d e g r e e s ( A e r o n a u t i c s )
from t h e C a l i f o r n i a I n s t i t u t e of Techno1 ogy.
Dr. Benenson's r e s e a r c h i n t e r e s t s i n c l u d e t h e
d i a g n o s t i c s and p h y s i c a l p r o c e s s e s a s s o c i a t e d w i t h
c i r c u i t i n t e r r u p t i o n , plasma processing, and plasma
chemistry.
He h a s b e e n a c t i v e l y i n v o l v e d i n t h e
a p p l i c a t i o n s of s p e c t r o s c o p i c , i n t e r f e r o m e t r i c , a n d
l a s e r v e l o c i m e t r i c t e c h n i q u e s i n s t u d i e s of t i m e v a r y i n g , f l o w i n g plasmas.
Dr. Benenson i s Chairman of t h e 1989 IEEE Conference on Plasma Science, which w i l l be h e l d i n B u f f a l o ,
N e w York.
V i c t o r Demianenko (S'80-M'83)
r e c e i v e d t h e B.S., MS.,
a n d PhD. d e g r e e s i n E l e c t r i c a l E n g i n e e r i n g f r o m t h e
S t a t e U n i v e r s i t y of New York a t B u f f a l o i n 1980, 1981,
and 1983, r e s p e c t i v e l y .
He i s a n A s s i s t a n t P r o f e s s o r i n t h e Department of
E l e c t r i c a l and Computer Engineering, S t a t e U n i v e r s i t y
of New Y o r k a t B u f f a l o .
H i s current research
i n t e r e s t s i n c l u d e network o p e r a t i n g systems, d a t a b a s e
s y s t e m s , and m i c r o p r o c e s s o r - b a s e d c o n t r o l and d i a g n o s t i c systems.
Minn L a i L a i i s a d o c t o r a l c a n d i d a t e i n t h e Department
of Mechanical and Aerospace Engineering a t t h e S t a t e
U n i v e r s i t y of New York a t B u f f a l o . H e r e c e i v e d t h e
B.S. degree i n Aerospace Engineering from t h e N a t i o n a l
Ching-Kung U n i v e r s i t y ( T a i w a n ) i n 1 9 7 9 and t h e M.S.
degree i n Mechanical Engineering f r a n t h e U n i v e r s i t y
H i s previous research has
a t B u f f a l o i n 1984.
r e s u l t e d i n a t h e o r e t i c a l f o u n d a t i o n and a n e x p e r i mental v e r i f i c a t i o n of t h e o p e r a t i o n of an e l e c t r w a g n e t i c flow meter f o r t h i n f i l m f l o w s H i s current
r e s e a r c h d e a l s with t r a n s i e n t power f l o w and machinery
diagnostics.
Yonn Hoon Lee (S'82-#84)
was born i n Seoul, Korea, on
J u l y 1 2 , 1955. H e r e c e i v e d t h e B.S. a n d IS. d e g r e e s
i n E l e c t r i c a l E n g i n e e r i n g f r o m S e o u l N a t i o n a l Univ e r s i t y , Seoul, Korea, i n 1978 and 1980, r e s p e c t i v e l y ,
and t h e Ph.D. d e g r e e i n S y s t e m s E n g i n e e r i n g f r o m t h e
U n i v e r s i t y of Pennsylvania, P h i l a d e l p h i a , i n 1984.
He h a s been w i t h t h e Department of E l e c t r i c a l and
C w p u t e r Engineering, S t a t e U n i v e r s i t y of New York a t
B u f f a l o , s i n c e 1984, where h e i s a n A s s i s t a n t
H i s research a c t i v i t i e s a r e i n the areas
Professor.
on one- and two-dimensional s i g n a l processing, which
i n c l u d e image p r o c e s s i n g and v i b r a t i o n s i g n a l
analy si s.
Chi Chann L i n i s a Ph.D. c a n d i d a t e i n t h e D e p a r t m e n t
of C i v i l E n g i n e e r i n g a t t h e S t a t e U n i v e r s i t y of N e w
York a t B u f f a l o . H e h a s a B.S. d e g r e e f r o m N a t i o n a l
C h u n g H s i n g U n i v e r s i t y a n d a n M.S. d e g r e e f r o m
N a t i o n a l Taiwan U n i v e r s i t y i n s u b j e c t s r e l a t e d t o
He
S t r u c t u r a l A n a l y s i s and S t r u c t u r a l Dynamics
worked f o r s e v e r a l y e a r s a s a s c i e n t i s t a t t h e
I n s t i t u t e of N u c l e a r E n e r g y ( T a i w a n ) a n d a s a
Mr. Lin i s a
consultant i n a c i v i l engineering f i r m
P r o f e s s i o n a l E n g i n e e r (Taiwan) a n d member of t h e
Chinese I n s t i t u t e of C i v i l and H y d r a u l i c Engineering.
H i s p r e s e n t r e s e a r c h i n t e r e s t s a r e focused on random
v i b r a t i o n s , s i g n a l a n a l y s i s , s t r u c t u r a l dynamics, and
a p p l i c a t i o n s t o earthquake e n g i n e e r i n g
H a r i s h K. N a i d u (S'87) r e c e i v e d t h e B.E d e g r e e i n
E l e c t r o n i c s a n d Communication E n g i n e e r i n g f r o m t h e
Col l e g e of E n g i n e e r i n g , Anna U n i v e r s i t y , Madras,
Authorized licensed use limited to: UNIVERSITY TENAGA NASIONAL. Downloaded on March 11,2010 at 05:08:29 EST from IEEE Xplore. Restrictions apply.
1731
India.
He i s c u r r e n t l y a g r a d u a t e s t u d e n t i n t h e
Department of E l e c t r i c a l and C m p u t e r Engineering a t
t h e S t a t e U n i v e r s i t y of New York a t B u f f a l o , working
towards h i s Master's d e g r e e
Soon Young P a r k (S'86) r e c e i v e d t h e B.S.
and M.S.
degrees i n E l e c t r o n i c Engineering from Yonsei
U n i v e r s i t y , S e o u l , Korea, i n 1 9 8 2 and 1984,
H e i s c u r r e n t l y working toward t h e
respectively.
Ph.D.
d e g r e e i n t h e D e p a r t m e n t of E l e c t r i c a l and
Computer E n g i n e e r i n g a t t h e S t a t e U n i v e r s i t y of New
York a t B u f f a l o
H i s r e s e a r c h i n t e r e s t s a r e i n t h e a r e a s of
a c o u s t i c s , v i b r a t i o n , and image s i g n a l p r o c e s s i n s
1965.
Dr. Wright was S c i e n t i f i c Advisor w i t h t h e French
g w e r m e n t (CNWA) from 1976-1978, moved t o S t a n f o r d
U n i v e r s i t y t o s t a r t a l a b o r a t o r y i n A c o u s t i c s i n 1978,
and j o i n e d EPRI i n 1 9 8 4 a s a P r o j e c t Manager i n t h e
E l e c t r i c a l Systems D i v i s i o n His s p e c i a l i t i e s i n c l u d e
a c o u s t i c a n d e l e c t r o m a g n e t i c f i e l d s , c o n t r o l s and
systems engineering
Dr. W r i g h t i s t h e a u t h o r of o v e r 40 j o u r n a l
p u b l i c a t i o n s.
Andrei K Beinhorn i s a n A s s o c i a t e P r o f e s s o r of C i v i l
E n g i n e e r i n g a t t h e S t a t e U n i v e r s i t y of New York a t
B u f f a l o . He r e c e i v e d theB.S. and Ph.D. d e g r e e s f r o m
Technion-Israel I n s t i t u t e of T e c h n o l o g y i n s u b j e c t s
r e l a t e d t o s t r u c t u r a l dynamics and e a r t h q u a k e e n g i neerins
He worked f o r s e v e r a l c i v i l e n g i n e e r i n g
f i r m s He i s a P r o f e s s i o n a l Engineer (New York) and a
Member of American S o c i e t y of C i v i l E n g i n e e r s ,
American S o c i e t y of Mechanical Engineers, and s e v e r a l
His
other professional c i v i l engineering s o c i e t i e s
p r e s e n t r e s e a r c h i n t e r e s t s a r e focused on a c t i v e and
pa s s i v e c o n t r o l of c i v i 1 e n g i n e e r i n g s t r u c t u r e s,
e x p e r i m e n t a l s t r u c t u r a l v i b r a t i o n s , random v i b r a t i o n s ,
and e a r t h q u a k e s i m u l a t i o n s .
He i s a u t h o r of o v e r 50
s c i e n t i f i c a r t i c l e s and r e p o r t s
Andres Soom r e c e i v e d h i s B.Eng. d e g r e e i n M e c h a n i c a l
Engineering f r m M c G i l l U n i v e r s i t y , Canada, i n 1967.
From 1 9 6 7 t o 1 9 6 9 h e worked i n t h e m a c h i n e t o o l
i n d u s t r y i n France.
I n 1970 h e s t a r t e d h i s graduate
s t u d i e s a t t h e U n i v e r s i t y of W i s c o n s i n - M a d i s o n ,
r e c e i v i n g t h e KS. and Ph.D. d e g r e e s i n M e c h a n i c a l
Engineering i n 1971 and 1976, r e s p e c t i v e l y .
F r m 1974 t o 1977 h e t a u g h t a t t h e u n i v e r s i t y of
W a t e r l o o , Canada.
S i n c e 1977 h e h a s been on t h e
f a c u l t y of t h e S t a t e U n i v e r s i t y of N e w York a t
B u f f a l o , where h e i s A s s o c i a t e P r o f e s s o r of Mechanical
and Aerospace E n g i n e e r i n s His c u r r e n t r e s e a r c h i s i n
t h e f i e l d s of t r i b o l o g y , v i b r o a c o u s t i c b e h a v i o r of
machines, i n s t r u m e n t a t i o n , and manufacturing s y s t e m s
Tsu T. Soong i s a P r o f e s s o r of C i v i l E n g i n e e r i n g and
Applied S c i e n c e s a t t h e S t a t e U n i v e r s i t y of N e w York
a t B u f f a l o . He i s a n I n t e r i m Deputy D i r e c t o r of t h e
N a t i o n a l C e n t e r f o r E a r t h q u a k e Engineering Research.
P r o f e s s o r Soong r e c e i v e d t h e KS. and PhD. d e g r e e s i n
E n g i n e e r i n g S c i e n c e f,rom P u r d u e U n i v e r s i t y and a
M e c h a n i c a l E n g i n e e r i n g d e g r e e f r o m U n i v e r s i t y of
D a y t o n (Ohio). He h a s b e e n a c o n s u l t a n t f o r s e v e r a l
l a r g e companies.
P r o f e s s o r Soong i s a R e g i s t e r e d
P r o f e s s i o n a l Engineer (New York) and a m e m b e r of ASCE,
ASMK AAAS, NSPE and s e v e r a l n a t i o n a l honor s o c i e t i e s .
He i s t h e r e c i p i e n t of v a r i o u s awards and f e l l o w s h i p s
f r o m NSF, N I H , and, r e c e n t l y , a r e c i p i e n t of a n
S c i e n t i s t Award.
His
Houmbolt Foundation S e n i o r U.S.
p r e s e n t r e s e a r c h i n t e r e s t s a r e i n t h e a r e a of random
t h e o r y and
v i b r a t i o n s and s t o c h a s t i c p r o c e s s e s,
a p p l i c a t i o n s of s t r u c t u r a l c o n t r o l , a n d e a r t h q u a k e
engineering.
Be i s t h e a u t h o r of t h r e e books ( o n
p r o b a b i l i t y and s i g n a l a n a l y s i s ) and o v e r 150 a r t i c l e s
and reports.
S e l w n E Wright r e c e i v e d t h e B . S d e g r e e i n Physics
i n 1960 from t h e N o r t h S t a f f 6 P o l y t e c h n i c , England,
and t h e I S . and Ph.D. d e g r e e s i n 1 9 6 4 ( E l e c t r o n i c s )
and 1969 (Acoustics) from Southampton U n i v e r s i t y .
He
became a C h a r t e r e d E n g i n e e r i n t h e U n i t e d Kingdom i n
T-
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