Improving the Performance of Saturated Cores Fault Current Limiters by Varying Winding Density in the AC Coils

Abstract

Effect of the winding density in the AC coils on the performance of a saturated cores fault current limiter (SCFCL) has been studied, exploiting Finite Element Analysis. For a given design, a fixed number of turns was concentrated at the center of the AC coils limb, resulting in high windings density. The coil length was then increased gradually along the limb, decreasing the winding density and therefore decreasing the coil impedance. However, we found that the ratio between the fault to nominal state impedances increases with decreasing winding density. The results are discussed and explained as originating from the change in the flux linkage of windings in the coil for various core states. In the nominal-state of the SCFCL, the core is saturated and the coupling between the windings is lower, given the lower winding density. However, when the core is desaturated during a fault, the magnetic interaction of the windings with the core strengthens, the coupling between the windings increases and contributes to higher fault-state impedance. Thus, reducing the winding density may serve in increasing the impedance ratio of the device and improving the performance of SCFCLs. The results suggest that the windings density in SCFCLs should be used as a significant design parameter.

Single core configurations of saturated core fault current limiter performance of laboratory test models

“…The concept in its basic form [19] has seen many modifications and studies while following the developments. The improved characteristics of novel SCFCL can easily be tuned to the general and specific grid requirements by adjusting the physical parameters of the magnetic core structure, AC and DC winding parameters and by controlling the DC bias current [20], [21]. The work addressed here belongs to the nonsuperconducting, novel SCFCL.…”

Saturated‐core fault current limiters for AC power systems: Towards reliable, economical and better performance application

“…The open‐closed SCFCL, illustrated in Fig. 3, is proved to have better clipping performance [30, 31].…”

“…The authors in [60] intensively investigated the correlation between the design parameters of coils and iron cores and their influence on FCL characteristics. The effect of the winding density in the AC coils on the performance of a SCFCL was studied in [30]. A methodology to simulate the dynamic behaviour of the saturated core SFCL in an electrical grid was presented in [61].…”

“…The open-closed SCFCL, illustrated in Fig. 3, is proved to have better clipping performance [30,31]. Take a prototype designed to limit fault currents in low voltage systems [up to 415 V root mean square (rms)] as an example, the clipping factor of open-core SCFCL is about 1.8.…”

Design Optimization of a Permanent-Magnet Saturated-Core Fault-Current Limiter

“…The first is the split in the AC coil. Following the concept described in [21], the coil is split so that the limbs' center region-where saturating field is in the core, due to its farthest distance from the permanent magnets-is minimal. Leaving this point under a lower exposure to direct AC flux helps it remain in a deeper saturated region during nominal grid operation.…”