Abstract-Although the Symmetrical Component Transformation has existed for 80 years, its application in the time-dependent form is practically restricted to the electric-machine theory. In the Power Systems field one uses the transformation applied to gteady-state ginusoidal phasors in a nonunitary form for fault calculations. For time-domain calculations the real equivalat, 0, , , is preferred, usually extended to 0, , -components. In network calculations, however, the application of time-dependent symmetrical components makes sense, since many net-component parameters are already available in this form. In this paper a short historical overview of the symmetrical-component transformation and the application of unitary and orthogonal transformations are presented. From these general transformations logic choices for base quantities necessary in per unit calculations will be derived. The relations between real and complex transformations, steady-state phasors and well-known sequence networks are given and illustrated through the use of some examples with asymmetrical faults.

The algorithm uses a modified continuous Fourier transformation that provides an accurate time domain computation. As an example, the interturn voltage distributions for two 500-kV autotransformers are computed and compared with measurements provided by other publications.

When an unloaded transformer or motor is switched under certain conditions, the circuit breaker can be exposed to a re-strike effect that leads to voltage escalation. The effect of reignition depends not only on the Qpe of circuit breaker, but also on the surrounding network.In this paper we describe a detailed model of all system components, which is extended where necessary, for the calculation of transients caused by the vacuum circuit breaker switching surges. Especially the transformer modelling is explained in detail for n broad frequency range because of a very complex transient behaviour. The system confguration consisting of a circuit breaker, a cable, a transformer and arresters is observed and modelled by means of some provided measured data. The results of some models are compared with measurements. The models have been imbedded into the Alternative Transient Program (ATP). The program developed here can be widely used for studies of transient recover?, overvoltages caused by interruption of transformer steady-state and inrush currents i f the measured data and parameters for the system components are known.

The algorithm uses a modified continuous Fourier transformation that provides an accurate time domain computation. As an example, the interturn voltage distributions for two 500-kV autotransformers are computed and compared with measurements provided by other publications.

Abstract-The utilization of wind and sun as renewable sources causes uncontrollable fluctuations in power generation. Furthermore, the ratio between peak power and average power is high for systems with a limited number of households. In small autonomous renewable energy systems (ARES), energy storage is needed; however, the use of Lead-acid batteries as energy buffers is problematic, since it is not possible to cover fast power fluctuations without dramatically reducing the batteries' lifetime. In this paper Super Capacitors are applied to relieve fast changes in the battery storage system. Batteries are used to meet the energy requirements and Super Capacitors are used to meet the instantaneous power demand. At the end of this paper, a sizing method is proposed for the Super Capacitor system.