This article describes a new method for dynamic simulation of multi-converter systems.This simulation is based on symmetrical components in time domain analysis and general representation of converter transformers to meet Y/, Y/Y, and Y/Z connections. The simulation is suitable for harmonic analysis of balanced and unbalanced AC voltages. The computed currents and voltages agreed reasonably with those measured and reported in the literature for the characteristic and non-characteristic harmonics.

This article describes a new method for dynamic simulation of multi-converter systems.This simulation is based on symmetrical components in time domain analysis and general representation of converter transformers to meet Y/, Y/Y, and Y/Z connections. The simulation is suitable for harmonic analysis of balanced and unbalanced AC voltages. The computed currents and voltages agreed reasonably with those measured and reported in the literature for the characteristic and non-characteristic harmonics.

Locating and classifying partial discharge due to sharp-edges, polluted insulators and loose-contacts in power systems significantly reduce the outage time, impending failure, equipment damage and supply interruption. In this paper, based on wavelet packets features of their modulated ultrasound emissions, an efficient novel scheme for neural network recognition of partial discharges is proposed. The employed preprocessing, wavelet features and near-optimally sized network led to successful classification up to 100%, particularly when longer duration signals are processed.

Locating and classifying partial discharge due to sharp-edges, polluted insulators and loose-contacts in power systems significantly reduce the outage time, impending failure, equipment damage and supply interruption. In this paper, based on wavelet packets features of their modulated ultrasound emissions, an efficient novel scheme for neural network recognition of partial discharges is proposed. The employed preprocessing, wavelet features and near-optimally sized network led to successful classification up to 100%, particularly when longer duration signals are processed.

Saturated profiles of the field intensity, current density and charge density at the ground surface and underneath monopolar HVDC transmission lines are calculated by using simple expressions. These expressions give the relation between the saturated values and the length of the field lines emanating from or terminating at the energized conductor. The calculated values are compared with those previously calculated and measured experimentally. Both absolute and normalized saturated corona profiles at the ground surface and underneath HVDC monopolar transmission lines are calculated using simple expressions. Relations between the saturated values at any position on the ground surface and the length of the field line emanating from or terminating at the conductor are given. These relationships are used for both outdoor and indoor models.

This paper is aimed at detecting the weak points in the distribution system of MEEC, "Middle Egypt Electricity Company". These include loose connections, polluted insulators and micro-roughness on line conductors and insulator hardware. The detection methodology is based on measuring ultrasound emissions from these weak points to warn against impending failures and subsequent supply interruptions. Laboratory testing made it possible to discriminate between loose-connection arcing, polluted-insulator "baby arcs" and sharp-edge corona according to the sound pattern. However, there can be occasions where sound pattern may prove confusing in discrimination between baby arcs and loose-connection arcing. In this case, recording of acoustic signals was found to be a useful tool for such discrimination.

The solution of monopolar corona equation already reported in literature is extended for bundle conductors using a modified iterative procedure to estimate the corona current contributed by each subconductor of the bundle. The solution is based on underlying assumptions, some of which are waived in the present calculations. The variation of ion mobility with its lifetime as well as the change of the corona onset voltage from point to point on each subconductor are taken into account for the first time. The calculated corona currents from each subconductor are compared with those measured experimentally for a laboratory model.

The solution of monopolar corona equation already reported in literature is extended for bundle conductors using a modified iterative procedure to estimate the corona current contributed by each subconductor of the bundle. The solution is based on underlying assumptions, some of which are waived in the present calculations. The variation of ion mobility with its lifetime as well as the change of the corona onset voltage from point to point on each subconductor are taken into account for the first time. The calculated corona currents from each subconductor are compared with those measured experimentally for a laboratory model.

The solution of monopolar corona equation already reported in literature is extended for bundle conductors using a modified iterative procedure to estimate the corona current contributed by each subconductor of the bundle. The solution is based on underlying assumptions, some of which are waived in the present calculations. The variation of ion mobility with its lifetime as well as the change of the corona onset voltage from point to point on each subconductor are taken into account for the first time. The calculated corona currents from each subconductor are compared with those measured experimentally for a laboratory model.

In this paper, the effect of wind on positive corona behavior up to breakdown is studied for point-plane gaps when the wind is flowing axially (against or parallel to the direction of ion convection from the point to the plane). The repetition rate of streamer pulses and its randomness as influenced by wind has been determined for different applied voltages. The spatial distribution of the current density over the ground plane has been examined for different applied voltages in still air and with wind blowing in the axial and transverse directions. The time-averaged value of wind-blown corona current as a function of the applied voltage was also determined. The results obtained are correlated with previous findings and with the theories of corona discharges.