A. Ninomiya

S. Yamada

T. Ishigohka

T. Mito

Y. Adachi

Y. Uriu

National Institute for Fusion Science (NIFS-Repository)

875287498743 8746time [s]Fig. 3 Balancevoltage ofH-I coil in local nonnal transition30.--------,-----,-------,-----,-------,'>E 20 1-----+----+-----11----+----1--------1.......,fa 10 f-----+----+----+-1t---4----f-------J.5g 08-10 r---'---+----it-ft----+----I-------Jc:C'O]-20-3087400.80.7B 0.6E(/) 0.5::Je 0.4Q)«I'"0 0.20.1 8740 8742 8744 8746 8748 8750 8752 8754time [s]Fig.4 Dangerous rate ofH-I coil in local nonnal transition0.80.7 1-----+----!---+----I-----I----I10.6 .....=---+---...-440.504 .. • .Je .c0.20.1o ----------- -------------- ------------------ -.1 _W M Wtime [s]Fig. 2 Dangerous rate ofH-I coil inquench.800 ,...----.,----r-------.---.------.----,r--'I 700 -----+-----1-------- ------ f-------600 1----+---+---+---+-----+---1500 f-----l---+---+---+----+---l1400.fJg 300 I-----r--+----+---l------t---+IJjli 100 1-----r--+----+----,--E........- .,. f"'J ..] 0 ... ... ,-1 00-200 L--_--'-__--'--_--'-__-L-_----l.__---ltime [s]Fig. 1 Balancevoltage ofH-I coil inquench.Meanwhile, the obtained balance voltage and the calculateddangerous rate ofH-I coil in case ofthe local nonnal transitionare shown inFig. 3 and 4, respectively.As mIl be seen in Fig. 3 and 4, it mIl be recognized that thedangerous rate does not shows any change for the local nonnaltransition§ 20. State Estimation of LargeSuperconducting Coil by HighlyUtilization of Voltage Signalsampling time. For the heat dissipation time constant "C, weapplied the value 1 [s]. And, the sampling time L1t wasselected to be 0.1 [s].The equivalent stored heat is used as the fourth inputvariable for the Fuzzy system in addition to the balanre voltage,the current, and the liquidhelium pressure.The balance voltage ofH-I coil and the dangerousrate for the data lliXlUired in October 1998 is shown in Fig. 1and 2, respectively. In this case, the balance voltage increasedup to about 700 mV, and the coil was shut down quickly.According to our system introdured the equivalent stored heat,the dangerous rate increased to higher than 0.5 whichindicates the alert level about 10 seconds earlier than the shutdown.(2)Where V; V V V are the balance voltoCYnC! at each, 1, 2 , 3 ' n -"'"6"""In the LHD superoonducting system which is composed ofanumber of large superoonducting coils, a high-peIfonnancestate estimation system ofa superoonductingcoil is essentialIn order to obtain a reliable state estimation system, anintelligent data proressing of voltage signals from the coilswould be preferable. In such a situation, the authors haveproposed to introdure a new estimation factnr into the quenchdetection system. We introdured a new conrept of theequivalent stored heat And, we figured out a comprehensivedecision factnr of"dangerousfactnr" using a FuzzytheoremThe equivalent stored heat byEquation (1).IT-t IWeff =J: e T • vi .dt (1)where, T: present time [s]v: balanre voltage [V]j: coil current [A]"C: heat dissipation time constant [s].In an actual we stored discretely the heatgeneratedin a period dt following Equation (2).jv: .e- & +V e- CJ.t +.. __jW = 1 2 XI-Ateff 1--M. _. +Vn-1e r: +VnIshigohka, T., Uriu, Y., Ninomiya, A., Adachi, Y.(Seikei Univ.)Mito, T., Yamada, S.112

State Estimation of Large Superconducting Coil by Highly Utilization of Voltage Signal

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