A Study on the Damping Loads Prediction to prevent Harmonic Resonance during the Power System Restoration

Abstract

-During the restoration process of primary restorative transmission system, some over voltages may happen due to nonlinear interaction between unloaded transformers and transmission systems. These over voltages caused by harmonic resonance can be suppressed by inserting damping loads before energizing transformers. But it is very difficult to predict the occurrence possibility of harmonic resonance and complex simulation must be repeated to estimate the sufficient damping loads. This paper presents a damping loads prediction system to prevent harmonic resonance. Detailed analysis of the relationship between harmonic resonance and the amount of damping loads is discussed. The prediction system is developed using a curve fitting and a neural network based on this relationship. A curve fitting used a Gaussian function based on non-linear least square method and multi-layer back-propagation neural network is applied. The system is applied to primary restorative transmission lines in korean power system and the result showed satisfactory performance.

A Study on Effect of Hybridisation of Supercapcitor With Battery for Blackstart

“…Therefore the length of the transmission line connecting the main generator and self-starting generator is also large. The energization of long distance noload transmission line during the blackstart process by hydro units can cause various problems such as Ferranti effect [2]. This will further delay the start of the main generators and hence delay the restoration process of the power system.…”

Analysis of Possibility of Replacing Self-starting Generator with BESS

“…Korea adopts the same method. However, this method can cause various problems such as the Ferranti effect [8], since the long-distance no-load transmission line is energized in restoration process. In this paper, the restoration process using BESS for primary transmission line was analyzed.…”