Research of Ferroresonance in 6-35 kV Electrical Networks Taking Into Account the Dynamic Model of Non-Linear Inductivity of Power Transformer

Abstract

Considering that distribution networks of 6-35 kV are the longest among electrical networks, one of the specialaspects of improving the reliability of power supply is the study of the effect of ferroresonance on the performance of voltage transformers (VT). Since the ferroresonant mode is quasi-stationary and occurs both at the fundamental frequency and at the subharmonic, the key role in the study is given to the creation of a dynamic model of the nonlinear inductance of the VT. The mathematical models and characteristics of the non-linear inductance of the VT and the resulting mathematical expressions proposed in well-known scientific papers are approximate and do not have sufficient accuracy for the analysis and qualitative assessment of ferroresonance in electrical networks of 6-35 kV. Since ferroresonance is characterized by non-linear abrupt modes of saturation of the VT magnetic circuit, the paper proposes a generalized dynamic model of the nonlinear VT inductance and more accurate analytical equations for the effective analysis of ferroresonance in 6-35 kV electrical networks.

Keywords

• ferroresonance
• electrical distribution networks of 6-35 kv
• voltage transformer
• generalised dynamic model
• non-linear inductance