The main problem preventing the use of digital relay protection mathematical models for real devices setting up is the confidentiality of the information about its internal configuration. This mainly concerns the input circuits (measuring part) of the protection, the components of which introduce the most significant errors. In this case, an arbitrary choice of the configuration may lead to incorrect results. The identification of the internal structure by standard methods, in particular by a real interpolation method, cannot be carried out in practice, due to the need to have input and output signals. In this regard, the purpose of the research was to develop a method of identification according to the time for formation of tripping signal. Identical signals were transmitted to real device and mathematical model of protection. The starting point of the time reference was the moment when the input signal reached a threshold; the final point was the time of tripping command appearance, unlike similar studies, where the time was determined by the closure of the output relay contacts. The research was carried out for 144 different combinations of the measuring part elements: Auxiliary converters, analog filters, digital finite impulse response filters. As a result, the combination in which the smallest deviation from the tripping time of the real device was observed in all studied modes was selected as the most 'optimal'. Performing such comparisons is the main way to make the model closer to real protection.
ASJC Scopus subject areas
- Electrical and Electronic Engineering