Transformation of Transient Overvoltages by Inductive Voltage Transformers

Area of Science:

• Electrical Engineering
• Power Systems Engineering

Background:

• Overvoltage transients are common in power networks due to switching events.
• These transients can be amplified in voltage transformer secondary circuits, risking device damage.
• Existing methods lack accurate prediction of these transformed overvoltages.

Purpose of the Study:

• To present a method for predicting slow-front transient overvoltages in inductive voltage transformer secondary circuits.
• To enhance the operational safety of measuring and protection devices connected to voltage transformers.
• To utilize harmonic ratio error for overvoltage prediction.

Main Methods:

• Analysis of inductive voltage transformer equivalent circuits, including winding capacitances.
• Determination of ratio error at harmonics for predicting transient overvoltage values.
• Modeling resonance phenomena involving leakage inductance and primary winding capacitance.

Main Results:

• A method to predict transformed slow-front transient overvoltages using harmonic ratio error is presented.
• The equivalent circuit model is extended to include internal capacitances for higher frequency analysis.
• Resonance is identified as a key factor driven by primary winding parameters.

Conclusions:

• Predicting transient overvoltages via harmonic ratio error improves secondary device safety.
• Understanding the role of internal capacitances is crucial for accurate transient modeling.
• The proposed method offers a proactive approach to prevent equipment malfunction.