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Modelowanie i analiza przepięć bardzo szybkozmiennych w elektroenergetycznych stacjach wysokiego napięcia izolowanych gazem SF6

Raczek R., Pająk P.

Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

2018

Nr 60

109--112

W systemach elektroenergetycznych dla celów przesyłowych i dystrybucyjnych szerokie zastosowanie znalazły stacje izolowane gazem SF6 (ang. Gas Insulated Substations – GIS). Podlegają one narażeniom podczas występowania przepięć bardzo szybkozmiennych (ang. Very Fast Transient Overvoltages – VFTO). Generowana w wyniku łączenia styków odłącznika fala przepięciowa naraża układy izolacyjne oraz aparaturę w rozdzielni gazowej GIS. W artykule zostaną przedstawione zasady modelowania zjawisk przejściowych oraz wyniki symulacji komputerowych dla operacji zamykania odłącznika zainstalowanego w stacji GIS. Obliczenia zostaną przeprowadzone z wykorzystaniem programu Electromagnetics Transients Program – Alternative Transients Program (EMTP–ATP). Wyniki symulacji pozwolą na określenie maksymalnych wartości szczytowych przepięć, ich stromości oraz częstotliwości.

In electric power systems, for transmission and distribution purposes, gas insulated substations (GIS) are found a wide application. In case of various transient phenomena like switching operations and lighting, the GIS are subjected to the very fast transients overvolatages (VFTO). As a result of GIS disconnector opening or closing, an electromagnetic wave is generated. Such a wave endanger insulation systems and equipment installed in the gas switchgear, including cable lines, overhead transmission lines and transformers. Overvoltages analysis for insulation coordination studies is carried out while maintaing the acceptable value of Swithing Impulse Withstand Level (SIWL). This paper presents a state of the art modeling principles of transient phenomena and computer simulations results for closing operation of GIS disconnector installed in gas insulated substation. Calculations will be conduct by using computer simulation program like Electromagnetics Transients Program – Alternative Transients Program (EMTP–ATP). Simulation results will let to determine maximum overvoltages peak values, steepness and frequency range of this overvoltages.

Multi-spark modeling of very fast transient overvoltages for the purposes of developing HV and UHV gas-insulated switchgear and of conducting insulation co-ordination studies

Szewczyk M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2017

Vol. 65, nr 6

871--882

Very fast transient overvoltages (VFTO) originate from steep voltage breakdowns in SF6 gas that are inherent to operation of any switching device of the gas-insulated switchgear (GIS) type. For power stations with voltage ratings exceeding 500 kV, the ratio between equipment rated- and withstand-voltage levels becomes relatively low, which causes the VFTO peak values to reach the component’s insulation withstand-voltage levels, thus becoming a design factor for high- and ultra-high voltage GIS. While well-established approach to VFTO analyses involves only single VFTO events (the so-called single-spark approach), there is often the need to analyze the entire VFTO generation process, for which the multi-spark approach to VFTO modeling is to be employed. The multi-spark approach allows one to evaluate the VFTO impact on the GIS disconnector design along with the impact of the VFTO on selection and dimensioning of the VFTO damping solutions. As the multi-spark approach to VFTO modeling is now being increasingly used in UHV GIS developments as well as for the insulation co-ordination studies of power stations, the present paper is motivated by the need to report on the VFTO multi-spark modeling approach and to lay a common ground for development works that are supported extensively with VFTO simulations. The paper presents physical assumptions and modeling concepts that are in use in such modeling works. Development of the multi-spark GIS disconnector model for VFTO simulations is presented, followed by an overview of examples of the model application for the GIS development works and for insulation co-ordination studies.