Out-of-Step Protection with AI Methods

In the paper the results of investigations on the application of Artificial Intelligence (AI) methods to the out-ofstep (OS) protection of synchronous machines are presented. The main efforts have been focused on development of new Artificial Neural Network (ANN) based and mixed protection techniques which should ensure better (faster and more secure) detection of generator loss of synchronism. The designed AI-based OS protection schemes have been thoroughly optimised and tested with EMTP-generated case signals. Wide robustness analysis as well as comparison with chosen standard OS detection method have also been performed

Electrochemistry of thorium in LiCl-KCl eutectic melts

This work presents a study of the electrochemical properties of Th chloride ions dissolved in a molten LiCl-KCl eutectic, in a temperature range of 693-823 K. Transient electrochemical techniques such as cyclic voltammetry and chronopotentiommetry have been used in order to investigate the reduction mechanism on a tungsten electrode and the diffusion coefficient of dissolved Th ions. All techniques showed that only one valence state was stable in the melt. The reduction into Th metal was found to occur according to a one-step mechanism, through an irreversible reaction controlled by a nucleation process which requires an overpotential of several 100 mV. At 723 K, the diffusion coefficient is DTh(723K) = 3.7 ± 0.2·10-5 cm2.s-1. EMF measurements indicated that, at 723 K, the standard apparent potential is *0ThCl4 /Th) E (723 K) = - 2.582 V vs. Cl2/Cl-, and the activity coefficient γThCl4(723 K) = 8·10-3 on the mole fraction scale (based on a pure liquid reference state)

Investigation of electrorefining of metallic alloy fuel onto solid Al cathodes

This work concerned the electrorefining of UZr and UPuZr alloys on a solid aluminium cathode, in the LiCl-KCl eutectic melt containing U3+, Pu3+, Np3+, Zr2+ or Zr 4+, Am3+, Nd3+, Y3+, Ce3+ and Gd3+ chlorides. During constant current electrolyses, the use of a cathodic cut-off potential (-1.25 V vs. Ag/AgCl) allowed to selectively deposit actinides (mainly U), while lanthanides remainedin the salt. The aim was to determine the maximal load achievable on a single aluminium electrode. The total exchange charge was 4300 C, which represents the deposition of 3.72 g of actinides in 4.17 g Al, yielding a composition of 44.6 wt% An in Al. It was shown that the melting of the cathode contributed to increase the total amount of actinides deposited on the aluminium

Simulative Analysis of a New Type Wide Range Estimator of Protection Criterion Values

In the paper a new adaptive estimator of protection criterion values insensitive to wide range power system frequency changes is proposed and analysed. Its operation is based on a coarse calculation of signal frequency and appropriate correction of used orthogonal filters frequency responses as well as adaptation of chosen parameters of the measurement algorithm. The main features of the new method has been compared with standard criterion values estimators both theoretically and by simulations. The proposed estimators assure good accuracy of measurement within the frequency range from 5 to 95 Hz

CT saturation correction based on the estimated CT saturation time constant

A new method for CT saturation correction is presented that is based on an on-line estimation of the CT magnetizing inductance. The approach adopted is based on numerical solution of the differential equation, which describes the saturated current transformer. The correction procedure proposed has been tested with EMTP-ATP signals proving to be an effective tool for primary current reconstruction

Magnetic and electrical properties of dhcp NpPd3 and U(1-x)Np(x)Pd3

We have made an extensive study of the magnetic and electrical properties of double-hexagonal closepacked NpPd3 and a range of U(1-x)Np(x)Pd3 compounds with x=0.01, 0.02, 0.05, and 0.50 using magnetization, magnetic susceptibility, electrical resistivity, and heat capacity measurements on polycrystalline samples, performed in the temperature range 2-300 K and in magnetic fields up to 9 T. Two transitions are observed in NpPd3 at T=10 and 30 K. Dilute Np samples (x<0.05) exhibit quadrupolar transitions, with the transition temperatures reduced from those of pure UPd3.Comment: 10 pages, 18 figure