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EXPERIMENTAL BEHAVIOUR OF A
CRYOALTERNATOR CONNECTED TO THE 50 Hz ELECTRICAL NETWORK
Y. Brunet, L. Paquien, J. Sabrié
To cite this version:
Y. Brunet, L. Paquien, J. Sabrié. EXPERIMENTAL BEHAVIOUR OF A CRYOALTERNATOR CONNECTED TO THE 50 Hz ELECTRICAL NETWORK. Journal de Physique Colloques, 1984, 45 (C1), pp.C1-709-C1-712. �10.1051/jphyscol:19841144�. �jpa-00223616�
JOURNAL DE PHYSIQUE
Colloque C1, supplCment au n o 1 , Tome 45, janvier 1984 page C1-709
E X P E R I M E N T A L BEHAVIOUR OF A CRYOALTERNATOR CONNECTED TO THE 50 Hz E L E C T R I C A L NETWORK
Y . B r u n e t , L . Paquien and J . L . s a b r i d i
C.iV.R.S.-C.R.T.B.T., B.P. 166 X, 38042 G r e n o b t e C e d e s , F r a n c e ' E ~ F , E t u d e s e t R e c h e r c h e s , 92240 C l a m a r t , F r a n c e
Rdsume -AprSs p l u s i e u r s e s s a i s 2 d e s v i t e s s e s i n f 6 r i e u r e s B 3000 t r l m i n , un c r y o a l t e r n a t e u r d e 500 kW a 6 t 6 r e l i c a u r 6 s e a u g6nEral EdF (50 Hz). Les es- s a i s (rggimes permanents e t r6gimes d e d 6 f a u t ) o n t dtG r 6 a l i s G s a u l a b o r a t o i - r e EdF d e St-Denis. P l u s i e u r s c o u p l a g e s e t c o u r t s c i r c u i t s o n t S t 6 r G a l i s 6 s r G v 6 l a n t l a f i a b i l i t g d e c e t t e t e c h n i q u e . Ces e s s a i s s o n t p r 6 s e n t 6 s . Le d i - pCle s u p r a c o n d u c t e u r a t r a v a i l 1 6 avec s o n c o u r a n t nominal, e t , e n c a s d e t r a n s i t i o n , l e temps d e r E c u p 6 r a t i o n d e 1 ' 6 t a t s u p r a c o n d u c t e u r e s t i n f 6 r i e u r
B 20 mn.
L'ensemble d e s r g s u l t a t s c o r r e s p o n d aux o b j e c t i f s q u i G t a i e n t f i x & 2 c e t t e Gtude, commenc6e il y a q u a t r e a n s .
A b s t r a c t - A f t e r a s e t of e x p e r i m e n t s made a t s p e e d s lower t h a n 3000 rpm, a 500 kW c r y o a l t e r n a t o r h a s b e e n c o n n e c t e d t o t h e 50 Hz e l e c t r i c a l network i n t h e EdF l a b o r a t o r y i n St-Denis. Permanent and t r a n s i e n t p e r f o r m a n c e s h a v e b e e n e x p l o r e d d u r i n g s e v e r a l h o u r s ; t h e machine working a s a n a l t e r n a t o r o r a c o n d e n s e r .
S h o r t c i r c u i t s and c o u p l k g were performed w i t h o u t any problems showing t h e r e l i a b i l i t y of t h i s t e c h n i q u e . These e x p e r i m e n t a l r e s u l t s a r e p r e s e n t e d . The s u p e r c o n d u c t i n g d i p o l e worked up t o i t s maximum c u r r e n t . I n c a s e of t r a n s i - t i o n i n t h e normal s t a t e of t h e S.C d i p o l e u n d e r f a u l t c o n d i t i o n s , t h e r e c o - v e r y t i m e i s l e s s t h a n 20 mn.
With t h e s e r e s u l t s , t h e g o a l s of t h i s e x p e r i m e n t a l study, begun f o u r y e a r s a g o i n t h e CNRS-CRTBT l a b o r a t o f y , have been a c h i e v e d .
I - INTRODUCTION
A 500 kW hypersynchronous d r i v e n c r y o a l t e r n a t o r h a s been d e s i g n e d and b u i l t i n t h e CNRS-CRTBT Laboratory-Grenoble. T h i s machine, d e s c r i b e d b e f o r e /I/, i s a b l e t o work i n t h e c l a s s i c a l c o n f i g u r a t i o n when a s i m p l e m o d i f i c a t i o n ( a d j u n c t i o n of 6 screws) i s made.
The f i r s t t e s t s , b o t h i n t h e hypersynchronous and c l a s s i c a l c o n f i g u r a t i o n , have been performed i n G r e n o b l e , from 1977 t o 1979 121. Then, t h e machine moved t o S t Denis- EdF L a b o r a t o t y t o c o m p l e t e f u r t h e r t e s t s . At t h e end of 1982, t h e e x p e r i m e n t a l s t u d y was a c h i e v e d .
The consumption of l i q u i d h e l i u m i s a b o u t 25 l / h ( u n d e r nominal c o n d i t i o n s ) and a 500 1 h e l i u m v e s s e l i s s u f f i c i e n t t o c o o l down and s u p p l y t h e e x p e r i m e n t .
I1 - PREVIOUS TESTS AND 50 Hz OPERATION
S t e a d y s t a t e and t r a n s i e n t t e s t s (no l o a d , s h o r t c i r c u i t , r e s i s t i v e l o a d ) h a v e been made i n G r e n o b l e showing t h a t t h e r e i s n o s i g n i f i c a n t a d v a n t a g e i n t h e hypersynchro- n o u s c o n f i g u r a t i o n 121. Connected t o a n a r t i f i c i a l network (500 kW Ward Leonard Group) t h e cryomachine h a s been e x t e n s i v e l y s t u d i e d a t s p e e d s around 2000 rpm t o a v o i d me-
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19841144
CI-710 JOURNAL DE PHYSIQUE
c h a n i c a l problems. The r e s u l t s of s y n c h r o n i z a t i o n and l o a d v a r i a t i o n t e s t s a r e r e - p o r t e d i n r e f . 3 . I n o r d e r t o r u n a t 3000 rpm, t h e s e a l s a l l o w i n g t h e r e c o v e r y of h e l i u m v a p o r s a r e removed. Temperature and v i b r a t i o n l e v e l s r e v e a l a good comport- - t a t 3000 rpm : t h e t e m p e r a t u r e of t h e b e a r i n g s r e m a i m l e s s t h a n 50°C and t h e v i - b r a t i o n l e v e l i s l e s s than 15 pm ( w i t h a maximum of 40 pm a t 2500 rpm, showing a c r i t i c a l f r e q u e n c y a t t h i s s p e e d ) . The machine i s now d r i v e n w i t h a n asynchronous motor f e d by t h e W.L. group. The o u t p u t i s connected t o t h e EdF network through a t r a n s f o r m e r a l l o w i n g d i f f e r e n t v o l t a g e s ( F i g . 1 ) .
111 - STEADY STATE OPERATION
Condenser t e s t s h a v e been performed w i t h two o u t p u t v o l t a g e s ( F i g . 2 ) . The maximum a b s o r b e d r e a c t i v e power i s g i v e n f o r v e r y s m a l l v a l u e s o f t h e f i e l d c u r r e n t , b e c a u s e t h e r e a c t a n c e s r a t i o & i s s m a l l e r t h a n f o r normal sycchronous machines. F o r t h e
> x -
1'1
same r e a s o n s , t h e curves$t((IF~ a r e n e a r l y s t r a i g h t and show a s i g n i f i c a n t s l o p e , i n - c r e a s i n g t h e s t a b i l i t y of t h e cyromachine under. l a g g i n g c o n d i t i o n s ( F i g . 3 ) . D e s p i t e t h e bad s t a b i l i t y of t h e W-L group it was p o s s i b l e t o r e a l i z e some s t e a d y s t a t e t e s t s , t h e machine working a s a motor o r a g e n e r a t o r (Table I ) .
TabLe I : S t e a d y - s t a t e o p e r a t i o n ( t h e t r a n s f o r m e r i s A 127 V / Y 38r) v / Q and
A 220 v/A 38'? v @
I V - TRANSIENTS E v
66,4 5 1 , 5
105
The major p a r t s of t h e t r a n s i e n t , t e s t s have been r e p o r t e d e l s e w h e r e / 3 / . Under seve- r e c o n d i t i o n s -such a s c o u p l i n g w i t h a phase d i f f e r e n c e n e a r i 7 - t h e s u p e r c o n d u c t i n g d i p o l e q u e ~ c h e s . The r e c o v e r y time i s l e s s t h a n 20 mn. The machine i s a b l e t o ope- r a t e w i t h -% % 2T/s ; a f t e r a s h o r t c i r c u i t , t h e e v o l u t i o n of t h e c u r r e n t s a r e t h e
T -
same a s t h g s e r e p o r t e d by some o t h e r a u t h o r s / 4 / ( f i g . 4 ) .
Some c o u p l i n g and sudden s h o r t c i r c u i t s have been made a t 50 Hz. Attempts o f cou- p l i n g between t h e g r i d and t h e cryomachine have been made w i t h d i f f e r e n t v a l u e s of t h e o u t p u t v o l t a g e . Even w i t h a d i f f e r e n c e o f 15 7, between t h e o u t p u t v o l t a g e and t h e main v o l t a g e , t h e c o u p l i n g succeeded g i v i n g u s t h e p r e c e e d i n g r e s u l t s . The cryo- machine h a s s u f f e r e d two sudden s h o r t c i r c u i t s ( p o i n t A i n F i g . 1 ) . The p r o t e c t i o n c i r c u i t s o f t h e g r i d worked a s t h e c u r r e n t r e a c h e d 620 A b u t no t r a n s i t i o n of t h e s u p e r c o n d u c t i n g d i p o l e , e n e r g e t i z e d w i t h 65 A ( 1 / 3 of i t s nominal v a l u e ) , o c c u r e d .
if^
6 3 , 2 49 6 4 , 5
100 9 2 , 5
V - CONCLUSION
The s e t o f e x p e r i e n c e s made on t h i s c r y o a l t e r n a t o r , a t 50 Hz o r a t s p e e d s lower t h a n 3000 rprn,gives a proof o f t h e good comportment o f s u c h a machine o n a n indus- t r i a l g r i d . The e f f i c i e n c y o f t h e s h i e l d s , e s p e c i a l l y d u r i n g t r a n s i e n t s and resyn- c h r o n i z a t i o n o p e r a t i o n s i s f a i r l y good.
'A 187,5
750 750 412,5
500
With t h e s e r e s u l t s , t h e g o a l s of t h e p r o t o t y p e have been a c h i e v e d . ' ~ V A
0 - 1 1 0
- 108 50 - 112,6
P k ~
3 7 , 5 8 6 , 2 112,5 71,3 127,5
Cryomachine s t a t e
Motor G e n e r a t o r
I ,
1*,
REFERENCES
/I/ : PINET C., BRUNET Y., "A 500 kW, 3000 rpm alternator of a new type", Electrical Machines and Electromechanics", vol. 3 (1979) 171.
/2/ : BRUNET Y., "Analyse des comportements cryogBniques, mCcaniques et Blectriques d'un cryoalternateur hypersynchrone de 500 kW", ThSse Grenoble 1980.
/3/ ; BRUNET Y., PA(IU1EN L., SABRIE J.C., "Experimental study of cryoalternators", Proceedings of ICEC 9, 416.
/ 4 / : YAMADA T. et al., "Nb Sn/NbTi SC windings for 30 MVA condensor", IEEE Trans Mag. vol. 17, n"5, Sept. 1931.
500 kw W- L group
suporconducting alternator motor
4 0 0 k v a t r a n s f o r m e r
50hz
Fig. 1 : Schematic diagram of the electric installation in EdF St Denis labora- tory
f7 = 30Xl trlmn
1OC - Fig. 2 : The cryoalternator in the synchronous condensor state, with 2 different transformer ratios.
0 150
d
Y P
"' z,
5'
A
,+' ,,A Z-- . V=66 V
.I */
m A P:12 kW d
A? +,'
A '
-100- V=117 V
&' P=20 kW
&""
,' -203
JOURNAL DE PHYSIQUE
F i g . 3 : STEADY STATE POWER DIAGPAM FOR A CLASSICAL TURi3OGENERATOR (xd = 2 pu) AND A SUPERCONDTTCTING YACHINE (xd = 0 , 5 pu) WITH THE SAME CHARACTERISTICS V , I .
I ? FIELD CURRENT LIMITATION 2 . TURBINE OUTPUT LIMITATION 3 . STATOR CURRENT LIMITATION 4 . STATIC STABIT,ITY LIMITATION
R e a c t i v e power a b s o r p t i o n i s l i m i t e d by t h e n a t u r a l s t a b i l i t y f o r t h e c l a s s i c a l c o n f i g u r a t i o n , w h i l e i t i s t h e s t a t o r c u r r e n t which g o v e r n s t h i s l i m i t f p r t h e c r y o g e n i c c a s e . L i k e w i s e , f i e l d c u r r e n t l i m i t a t i o n i s governed by e x t e r n a l t h e r m a l c o n s i d e r a t i o n ( c o o l i n g system) i n t h e c l a s s i c a l machine and by t h e maximum c r i t i c a l v a l u e o f t h e s u p e r c o n d u c t o r ( i n t r i n s e c p h y s i c a l l i m i t ) .
1
, short circuit duration , I
100
Q =I800 rpm
F i g . 4 : V a r i a t i o n o f s t a t o r and f i e l d c u r r e n t d u r i n g a 0 , 5 s s h o r t c i r - looms
I I > cryomachine.
c u i t a t t h e mains o f t h e
