The Analysis of Biphasic Short Circuit Regimes to Doubly-fed Induction Generators Connected to a Power System

Abstract

The paper presents analysis of the biphasic short circuit regimes at the terminals of doubly fed induction generator connected to the national power system of the Republic of Moldova. Research related to connecting wind farms to the national electricity system have shown vulnerability related to the supply or consumption of reactive power especially in short circuit regimes with locking rotor inverter. Reactive power consumption asynchronous generator increases essentially under unbalanced and is related to increased rotor reactance about negative sequence currents. The biphasic short-circuit is the high degree of asymmetry 100% (U1/U2=1). Besides increasing the reactive component of current are increasing resulting critical current value. Under asymmetrical regimes because direct and reversed sequence components interaction appear dual-frequency pulses (100Hz) of active and reactive powers, dangerous mechanical couples due to resonance of mechanical parts.