Distribution of Electrical Power Using GIS

This paper presents a comparative analysis of gas insulated substation and air insulated substation. A brief study of both the substations is carried out. As the electricity demand is increasing day by day, the power companies are giving their active participation in fulfilling the consumer demand. The design of power substation is classified as air insulated substation and gas insulated substation where the air and gas has a key role in providing insulation. An AIS unit is basically a conventional switchgear technology where air is used as a primary dielectric for insulation. Key property of AIS unit is step-up systems in connection with power stations and transformer substations in the extra high voltage transmission system. Whereas the gas insulated substation works on the principle operation of completely enclosure of all the energized parts in metallic encapsulation compressed within sulphur hexafluoride gas. Both the substations have equal merits and demerits in different aspects. Taking into account a comparative analysis is made regarding design aspects, power losses, cost and reliability.

European Transactions on Electrical Power, 2011

China is in urgent need of electrical power. Huge power plants are built all over the country and the enormous flow of electrical power to the large megacities has to cross several thousand kilometres from the source to the end user. At those dimensions, losses of the power lines can be significant. The State Grid Corporation of China (SGCC) is thus aiming for 1100 kV as the voltage level for AC transmission to keep losses as low as possible, a step into a new area of electrical grids. Asea Brown Boveri (ABB), together with its partners and suppliers, has developed the heart of such a system-a gas-insulated switchgear (GIS) design-that could pass all the tests with this groundbreaking technology. Many years of experience at voltage levels of up to 800 kV are available as the basis for developing GIS for 1100 kV. Nevertheless, the individual components such as circuit-breakers (CB) and disconnectors differ greatly from the known designs. As regards the CB, for instance, it emerges that a design with the closing resistor in a parallel tank is advantageous. The very fast transient overvoltages become more important for the disconnector design.

2015 IEEE 15th International Conference on Environment and Electrical Engineering (EEEIC), 2015

This paper presents the EMC (Electromagnetic Compatibility) philosophy applied to design the grounding systems of GIS Insulated Substation -GIS indoor substation. The grounding systems are characterized by the following subsystems: Main Grounding grid (60 Hz Grounding System), Equipotential Grounding grid (HF Grounding system) and Lightning Grounding system. The real case measurements for 100 MVA, 69/13.8 kV GIS indoor distribution substation indicated that adopted EMC philosophy is appropriate because the maximum measured potential difference among the various grounding systems of GIS indoor substation was approximately zero volts and the maximum measured touch voltage was less than 1.4 volts.

standard

Appareillage à haute tension-Partie 203: Appareillage sous enveloppe métallique à isolation gazeuse de tensions assignées supérieures à 52 kV High-voltage switchgear and controlgear-Part 203: Gas-insulated metal-enclosed swithgear for rated voltages above 52 kV Numéro de référence Reference number

2001

Transient enclosure voltage rise (TEVR) of the gas insulated switchgear (GIS) is the result of the very fast transient overvoltages (VFTO) caused by the operation of the switching devices, particularly disconnectors. It is closely connected to the applied solutions of grounding and enclosure interconnections with the grounding system. This paper gives the summary of the characteristic results of the efficiency measures for the decreasing the TEVR. The researches are based on the computer simulations and extensive measurements done on the real switchgear.

The SF6 gas insulated switchgear has increasingly been used for high voltage and extra high voltage systems. The transient electromagnetic field generated in a gas insulated substation during the switching operation has become very important in high voltage systems. These paper deals, design of suitable simulation diagram for obtaining switching over voltages and prediction of ground faults premature convergence in a substation. The suitable simulation equivalent circuit designed for two cases i) 5mts length of GIS system ii) 10 mts length of GIS system. EMTP is used to develop equivalent circuits for estimate of transient over voltages in GIS system for 5mts and 10 mts length and compared these two system cases. Due to travelling nature of the transient the of GIS makes use of electrical equivalent circuit composed by lumped elements and especially by distributed parameter lines, Surge impedances and travelling times. The proposed system successfully implemented in the platform of MATLAB Package. The so formed model has been experimentally verified, indicating the models acceptable accuracy and feasibility of the simulation.