Geomagnetically Induced Current Calculation of High Voltage Power System with Long Transmission Lines using Kriging Method

Calculation of geomagnetically induced current (GIC) flowing through power system during the geomagnetic storm has attracted more attention recently. However, for high voltage power systems with transmission lines over hundreds or even thousands of kilometers, the earth model and geomagnetical field generally vary significantly. So, its essential to take them into consideration using limited earth survey sites and geomagnetic observatories. To address this problem, a Kriging method is introduced in this paper to make earth model and geomagnetical field interpolations. It has the characteristic of spatial autocorrelation by considering not only the distances between predicted points and training points but also the distances between training points themselves. Finally, a case study of the Central China 1000 kV ultra-high voltage (UHV) grid is carried out to illustrate the applicability and effectiveness of the proposed method

Failure times prediction of field-distortion gas switch based on electrode surface roughness

Prediction of switch failure times has a great influence on determining the repair cycle of gas switch and pulse power system, preventing accidents, and reducing cost. In this paper, electrode surface roughness (ESR) is proposed to analyze switch performance and predict switch failure times. According to the one-dimensional equation of heat conduction and the thermal equilibrium equation near the electrode surface, the etch pit depth can be calculated with different discharge conditions. And then, the electrode surface roughness has been obtained by calculating the deepest etch pits depth and the burr peak height in the electrode erosion region for the same discharge condition. The switch failure times can be predicted by the trend of the ESR according to discharge times. Experimental results indicate that the calculation model of switch failure times can be used to predict the switch failure times effectively

Study on heat fluxes and their effect on electrode material removal on the copper electrode of a field-distortion gas spark switch

Gas switch is one of the key elements in pulsed-power devices, and electrode erosion is a key restrictive factor in high-power gas switch development and application. According to the thermal equilibrium equation near the electrode surface, this paper calculates electrode heat fluxes and their peak powers caused under different discharge conditions, and analyses their effects on the removal method of electrode materials. When discharge current is not too high, calculation results indicate that the arc joule heat is the main cause of electrode erosion and solid material removal may appear. Vaporization of electrode material is the main cause of electrode erosion when discharge current is high enough