Three-Phase Saturated-Core Fault Current Limiter

Abstract

The saturated-core fault current limiter (SFCL) is widely used to limit the fault current. However, in the conventional SFCL structure, alternating current (AC) and direct current (DC) coils are wound on different loosely coupled cores. Owing to the leakage inductance, the traditional structure demonstrates relatively large demand for DC excitation power and excessive impedance during saturation. In this study, a new structure for winding closely coupled DC and AC coils on the same core in three phases is proposed to reduce the influence of leakage reactance on the SFCL performance. The leakage magnetic flux generated by both structures is analyzed by performing finite element analysis simulations and utilizing a magnetic field division method. The impedance of the limiter is measured at different DC currents and air gaps to optimize its dynamic performance. A fabricated prototype of the proposed limiter exhibits smaller steady-state losses and high current-limiting capability.

Novel Topology of DC Energy-Released Circuit For Saturated-Core Fault Current Limiter

“…However, comparing with the voltage of the DC source used in this experiment, the induction voltage on DC coil is almost negligible which proves that the novel structure does not have too much influence on the insulation of DC coil. Thus, the DC circuit which is not elucidated in reference [37] is supplemented. Secondly, a novel type of DC circuit is proposed in this paper which uses diodes to form a freewheeling branch to provide the reverse electromotive force for the energy released circuit, and accelerates the speed of releasing energy in the DC coil.…”

“…According to Maxwell's equations, the formula (1) can be derived. The leakage inductance of SCFCL can be obtained by magnetic field division method which is calculated as follows [37]:…”

“…Equivalent electromagnetic circuit of the tightly-coupled SCFCL is shown in Figure 6.According to Maxwell's equations, we can get formula (11). The leakage inductance of TSCFCL can be obtained by magnetic field division method which is calculated as follows [37]:…”

“…This paper mainly discusses a novel tightly-coupled SCFCL [37]. The voltage across the DC coil and the current flowing in the DC coil are analyzed in following paragraphs.…”

Fault Ride Through Capability Improvement of DFIG Based Wind Farm Using Nonlinear Controller Based Bridge-Type Flux Coupling Non-Superconducting Fault Current Limiter

“…Over the years, several types of FCLs have been proposed for the augmentation of FRT capability of power systems in numerous studies [15,16]. Each FCL has its advantages and disadvantages, and they demand specific environment to perform efficiently [17].…”