New Protection Scheme Based on Coordination with Tie Switch in an Open-Loop Microgrid

Self Cite

The demand for a low voltage direct current (LVDC) microgrid is increasing by the increase of DC-based digital loads and renewable resources and the rapid development of power electronics technology. For the stable operation of an LVDC microgrid, it is necessary to develop a protection method. In this paper, the new protection scheme considering the fault section is proposed using wavelet transform (WT) in an LVDC microgrid. The fault sections are classified into DC side of the alternating current (AC)/DC converter, DC/DC converter connected to photovoltaic (PV) system, DC line, and DC bus. The characteristics of fault current at each fault section are analyzed. Based on these analyses, the new protection scheme including the fault section estimation is proposed using WT. The proposed scheme estimates the fault section using the detail component after performing WT and sends the trip signal to each circuit breaker according to the fault section. The proposed protection scheme is verified through various simulations according to the fault region and fault current using electromagnetic transient program (EMTP)/ATPDraw and MATLAB. The simulation results show that the fault section is accurately determined, and the corresponding circuit breaker (CB) operations are performed.

“…In signal processing, the WT can be obtained by scaling and moving the mother wavelet. Therefore, it is very important to select an appropriate mother wavelet [26][27][28].…”

Section: Wavelet Transformmentioning

confidence: 99%

“…In [19][20][21][22][23][24], WT was applied to protect transmission lines. For distribution system protection, the WT was applied to microgrid protection [25][26][27]. In [28], it was applied to the reclosing of the distribution system.…”

Section: Introductionmentioning

confidence: 99%

Development of New Protection Scheme in DC Microgrid Using Wavelet Transform

Seo¹

2022

Self Cite

“…Therefore, it is very important to select an appropriate mother wavelet. Among the various mother wavelets, sym5 has been widely used for power system transients and protection [17][18][19]. Therefore, in this paper, the mother wavelet is also selected as sym5.…”

Section: Fault Section Estimation Using Wavelet Transformmentioning

confidence: 99%

“…WT has been widely used for power system transient analysis and protection. The WT has been variously applied in the alternating current (AC) transmission and distribution system [17][18][19]. Therefore, WT can be applied to the protection in LVDC microgrid.…”

Section: Introductionmentioning

confidence: 99%

Fault Section Estimation in Radial LVDC Distribution System Using Wavelet Transform

Seo

Gwon

Park³

2021

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The demand for low voltage DC (LVDC) distribution systems is increasing due to the rapid development of power conversion technology, the increase of DC-based digital loads, and the expansion of DC-based distributed generation (DG). For the stable operation of the LVDC distribution system, it is necessary to develop a protection method. In this paper, the fault section is estimated using wavelet transform (WT) in LVDC distribution system. The fault section is classified into a DC line and a DC bus. The characteristics of fault current at each fault section part are analyzed in simple and actual LVDC system. Based on this analysis, the algorithm for fault section estimation is proposed using the detail component after performing WT. The results of fault section estimations are verified through various simulations using EMTP and MATLAB. The fault section estimation can be utilized in the development of protection schemes in LVDC distribution system.

“…In open-loop distribution systems, a protection relay can mal-operate due to the tie switch operation. Meanwhile, in closed-loop distribution systems, the protection relay can mal-operate due to bidirectional current flow [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

New Protection Scheme in Loop Distribution System with Distributed Generation

Seo¹

2020

Self Cite

Loop distribution systems are increasingly used for reasons such as increased distributed generation (DG) and increased demand for a reliable and high-quality power supply. Because the loop distribution system involves bidirectional power flow, the method for protection of the radial distribution system cannot be applied. Therefore, a protection method is proposed herein for loop distribution systems. In this study, the existence of DG is also considered. According to the proposed method, the fault point is estimated on the basis of the equivalent circuit of the distribution system. Then, the fault section is determined and separated from the distribution system. The separation of DG is determined depending on whether the frequency and voltage are maintained within the steady state ranges. The proposed method is modelled and verified using the Electromagnetic Transients Program. Simulations according to the fault location are performed and analyzed. The results show that the method accurately determines the fault section so that normal power can be supplied to the healthy sections in the distribution system.