Case study on transformer models for calculation of high frequency transmitted overvoltages

Events such as lightning, switching of vacuum circuit breaker or operations in gas insulated substation (GIS) generate high frequency overvoltages. An equipment a transmission distribution system has to be protected against phenomena. Unfortunately, the traditional transformer models available Electromagnetic transient simulations program (EMTP-like) software packages are not capable representing behavior state, which includes frequencies. Moreover, often too complex require confidential information on geometry. However, design stage insulation coordination it is particularly important accurately calculate transmitted overvoltages through transformers. In scope this paper two different for frequency, developed an EMTP-type program. The first model named “Black box” derives solely from values measured terminals and does any knowledge inner second “Grey box”, based lumped RLC parameters network, whose derived simple geometry window nameplate data. Furthermore, models’ capabilities characterize at frequencies analyzed. case study done located inside power plant. calculated with compared measurements.