# Decentralized Plug-and-Play Protection Scheme for Low Voltage DC Grids

^{1}

^{2}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Short-Circuit Fault Currents in Low Voltage DC Grids

## 3. Experimental Setup

#### 3.1. Power Electronic Converters Emulated by DC Power Supplies

#### 3.2. Data Acquisition

#### 3.3. Distribution Line Emulation Circuit

#### 3.4. Solid-State Circuit Breaker

#### 3.5. Experimental Validation of the SSCB

## 4. Non-Unit Protection Scheme Challenges

#### 4.1. Fast Fault Propagation

#### 4.2. Commutation of Inductive Currents

## 5. Proposed Plug-and-Play Protection Scheme

#### 5.1. Proposed SSCB Topology to Delay Fault Propagation

#### 5.2. Proposed Time-Current Characteristic

#### 5.3. Plug-and-Play Design Guidelines

## 6. Experimental Validation of the Plug-and-Play Protection Scheme

#### Discussion

## 7. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

- Hakala, T.; Lahdeaho, T.; Jarventausta, P. Low-Voltage DC Distribution—Utilization Potential in a Large Distribution Network Company. IEEE Trans. Power Deliv.
**2015**, 30, 1694–1701. [Google Scholar] [CrossRef] - Allee, G.; Tschudi, W. Edison Redux: 380 Vdc Brings Reliability and Efficiency to Sustainable Data Centers. IEEE Power Energy Mag.
**2012**, 10, 50–59. [Google Scholar] [CrossRef] - Larruskain, D.M.; Zamora, I.; Abarrategui, O.; Aginako, Z. Conversion of AC distribution lines into DC lines to upgrade transmission capacity. Electr. Power Syst. Res.
**2011**, 81, 1341–1348. [Google Scholar] [CrossRef] - Guerrero, J.M.; Vasquez, J.C.; Matas, J.; de Vicuna, L.G.; Castilla, M. Hierarchical Control of Droop-Controlled AC and DC Microgrids: A General Approach Toward Standardization. IEEE Trans. Ind. Electron.
**2011**, 58, 158–172. [Google Scholar] [CrossRef] - Arcidiacono, V.; Monti, A.; Sulligoi, G. Generation control system for improving design and stability of medium-voltage DC power systems on ships. IET Electr. Syst. Transp.
**2012**, 2, 158–167. [Google Scholar] [CrossRef] - Gregory, G.D. Applying low-voltage circuit breakers in direct current systems. IEEE Trans. Ind. Appl.
**1995**, 31, 650–657. [Google Scholar] [CrossRef] - Dragicevic, T.; Lu, X.; Vasquez, J.C.; Guerrero, J.M. DC Microgrids—Part II: A Review of Power Architectures, Applications, and Standardization Issues. IEEE Trans. Power Electron.
**2016**, 31, 3528–3549. [Google Scholar] [CrossRef] [Green Version] - Brearley, B.J.; Prabu, R.R. A review on issues and approaches for microgrid protection. Renew. Sustain. Energy Rev.
**2017**, 67, 988–997. [Google Scholar] [CrossRef] - Hailu, T.; Mackay, L.; Gajic, M.; Ferreira, J.A. Protection coordination of voltage weak DC distribution grid: Concepts. In Proceedings of the IEEE 2nd Annual Southern Power Electronics Conference (SPEC), Auckland, New Zealand, 5–8 December 2016. [Google Scholar]
- Shen, Z.J. Ultrafast Solid-State Circuit Breakers: Protecting Converter-Based ac and dc Microgrids Against Short Circuit Faults. IEEE Electrif. Mag.
**2016**, 4, 66–70. [Google Scholar] [CrossRef] - Guillod, T.; Krismer, F.; Kolar, J.W. Protection of MV Converters in the Grid: The Case of MV/LV Solid-State Transformers. IEEE J. Emerg. Sel. Top. Power Electron.
**2017**, 5, 393–408. [Google Scholar] [CrossRef] - Qi, L.; Antoniazzi, A.; Raciti, L. DC Distribution Fault Analysis, Protection Solutions, and Example Implementations. IEEE Trans. Ind. Appl.
**2018**, 54, 3179–3186. [Google Scholar] [CrossRef] - Brozek, J.P. DC overcurrent protection-where we stand. IEEE Trans. Ind. Appl.
**1993**, 29, 1029–1032. [Google Scholar] [CrossRef] - ABB. Circuit-Breakers for Direct Current Applications. Available online: https://library.e.abb.com/public/de4ebee4798b6724852576be007b74d4/1SXU210206G0201.pdf (accessed on 17 June 2020).
- Lazzari, R.; Piegari, L. Design and Implementation of LVDC Hybrid Circuit Breaker. IEEE Trans. Power Electron.
**2019**, 34, 7369–7380. [Google Scholar] [CrossRef] - Sato, Y.; Tanaka, Y.; Fukui, A.; Yamasaki, M.; Ohashi, H. SiC-SIT Circuit Breakers With Controllable Interruption Voltage for 400-V DC Distribution Systems. IEEE Trans. Power Electron.
**2014**, 29, 2597–2605. [Google Scholar] [CrossRef] - Miao, Z.; Sabui, G.; Chen, A.; Li, Y.; Shen, Z.J.; Wang, J.; Shuai, Z.; Luo, A.; Yin, X.; Jiang, M. A self-powered ultra-fast DC solid state circuit breaker using a normally-on SiC JFET. In Proceedings of the IEEE Applied Power Electronics Conference and Exposition (APEC), Charlotte, NC, USA, 15–19 March 2015; pp. 767–773. [Google Scholar]
- Bayati, N.; Hajizadeh, A.; Soltani, M. Protection in DC microgrids: A comparative review. IET Smart Grid
**2018**, 1, 66–75. [Google Scholar] [CrossRef] - Mirsaeidi, S.; Said, D.; Mustafa, M.; Habibuddin, M.; Miveh, M. A Comprehensive Overview of Different Protection Schemes in Micro-Grids. Int. J. Emerg. Electr. Power Syst. (IJEEPS)
**2013**, 14, 327–332. [Google Scholar] [CrossRef] - Meng, L.; Shafiee, Q.; Trecate, G.F.; Karimi, H.; Fulwani, D.; Lu, X.; Guerrero, J.M. Review on Control of DC Microgrids and Multiple Microgrid Clusters. IEEE J. Emerg. Sel. Top. Power Electron.
**2017**, 5, 928–948. [Google Scholar] - Salomonsson, D.; Soder, L.; Sannino, A. Protection of Low-Voltage DC Microgrids. IEEE Trans. Power Deliv.
**2009**, 24, 1045–1053. [Google Scholar] [CrossRef] - Meghwani, A.; Srivastava, S.C.; Chakrabarti, S. A Non-unit Protection Scheme for DC Microgrid Based on Local Measurements. IEEE Trans. Power Deliv.
**2017**, 32, 172–181. [Google Scholar] [CrossRef] - Sneath, J.; Rajapakse, A.D. Fault Detection and Interruption in an Earthed HVDC Grid Using ROCOV and Hybrid DC Breakers. IEEE Trans. Power Deliv.
**2016**, 31, 973–981. [Google Scholar] [CrossRef] - Yang, J.; Fletcher, J.E.; O’Reilly, J. Short-Circuit and Ground Fault Analyses and Location in VSC-Based DC Network Cables. IEEE Trans. Ind. Electron.
**2012**, 59, 3827–3837. [Google Scholar] [CrossRef] [Green Version] - Mohanty, R.; Pradhan, A.K. A Superimposed Current Based Unit Protection Scheme for DC Microgrid. IEEE Trans. Smart Grid
**2018**, 9, 3917–3919. [Google Scholar] [CrossRef] - Bertho, R.; Lacerda, V.A.; Monaro, R.M.; Vieira, J.C.M.; Coury, D.V. Selective Nonunit Protection Technique for Multiterminal VSC-HVDC Grids. IEEE Trans. Power Deliv.
**2018**, 33, 2106–2114. [Google Scholar] [CrossRef] - Som, S.; Samantaray, S.R. Efficient protection scheme for low-voltage DC micro-grid. IET Gener. Transm. Distrib.
**2018**, 12, 3322–3329. [Google Scholar] [CrossRef] - Feng, X.; Qi, L.; Pan, J. A Novel Fault Location Method and Algorithm for DC Distribution Protection. IEEE Trans. Ind. Appl.
**2017**, 53, 1834–1840. [Google Scholar] [CrossRef] - Tang, L.; Ooi, B. Locating and Isolating DC Faults in Multi-Terminal DC Systems. IEEE Trans. Power Deliv.
**2007**, 22, 1877–1884. [Google Scholar] [CrossRef] - Emhemed, A.A.S.; Burt, G.M. An Advanced Protection Scheme for Enabling an LVDC Last Mile Distribution Network. IEEE Trans. Smart Grid
**2014**, 5, 2602–2609. [Google Scholar] [CrossRef] [Green Version] - Fletcher, S.D.A.; Norman, P.J.; Fong, K.; Galloway, S.J.; Burt, G.M. High-Speed Differential Protection for Smart DC Distribution Systems. IEEE Trans. Smart Grid
**2014**, 5, 2610–2617. [Google Scholar] [CrossRef] [Green Version] - Farhadi, M.; Mohammed, O.A. Event-Based Protection Scheme for a Multiterminal Hybrid DC Power System. IEEE Trans. Smart Grid
**2015**, 6, 1658–1669. [Google Scholar] [CrossRef] - Farhadi, M.; Mohammed, O.A. A New Protection Scheme for Multi-Bus DC Power Systems Using an Event Classification Approach. IEEE Trans. Ind. Appl.
**2016**, 52, 2834–2842. [Google Scholar] [CrossRef] - Emhemed, A.A.S.; Fong, K.; Fletcher, S.; Burt, G.M. Validation of Fast and Selective Protection Scheme for an LVDC Distribution Network. IEEE Trans. Power Deliv.
**2017**, 32, 1432–1440. [Google Scholar] [CrossRef] [Green Version] - Monadi, M.; Gavriluta, C.; Luna, A.; Candela, J.I.; Rodriguez, P. Centralized Protection Strategy for Medium Voltage DC Microgrids. IEEE Trans. Power Deliv.
**2017**, 32, 430–440. [Google Scholar] [CrossRef] - Park, J.; Candelaria, J. Fault Detection and Isolation in Low-Voltage DC-Bus Microgrid System. IEEE Trans. Power Deliv.
**2013**, 28, 779–787. [Google Scholar] [CrossRef] - Wang, L. The Fault Causes of Overhead Lines in Distribution Network. MATEC Web Conf.
**2016**, 61, 02017. [Google Scholar] [CrossRef] [Green Version] - Paul, C.R. Analysis of Multiconductor Transmission Lines; Wiley-IEEE Press: Hoboken, NJ, USA, 2007; ISBN 0470131543. [Google Scholar]

**Figure 2.**Simulation results for the fault current in the equivalent circuit of Figure 1 for different fault resistances and distribution line lengths.

**Figure 3.**SM 500-CP-90 bidirectional power supply from Delta Elektronika, which is used to emulate the power electronic converters in low voltage dc grids.

**Figure 8.**Experimental results when the SSCB is short-circuited with a high fault resistance resulting in the overcurrent detection being triggered when the current exceeds 21 A.

**Figure 9.**Experimental results when the SSCB is short-circuited with a low fault resistance resulting in the di/dt detection being triggered when the 20 V (20 MA/s) threshold is exceeded for a longer time.

**Figure 10.**(

**a**) Schematic and (

**b**) picture of the experimental setup connecting a constant voltage source to two constant current loads through three SSCBs.

**Figure 11.**Experimental results for the system shown in Figure 10, showing that fault propagation can cause unnecessary tripping in low inductive systems.

**Figure 12.**(

**a**) Schematic and (

**b**) picture of the experimental setup connecting a constant voltage source and two constant current loads connected through an inductive line.

**Figure 13.**Experimental results for the system shown in Figure 12, showing that the commutation of inductive currents can cause unnecessary tripping (the right figure is a zoom in).

**Figure 15.**Circuit that is used to show the effect of the RC dampers on the commutation of an (inductive) current.

**Figure 16.**Simulation results for the inductor current in the circuit of Figure 15 for different damper capacitances.

**Figure 17.**Proposed time-current characteristic for the plug-and-play protection scheme, where ${t}_{\mathrm{max}}$ is the maximum time that the SSCB needs to detect and interrupt an overcurrent.

**Figure 18.**Experimental results for the system shown in Figure 10, showing that fault propagation is delayed with the plug-and-play SSCBs.

**Figure 19.**Experimental results for the system shown in Figure 12, which show smooth commutation and selectivity with the plug-and-play SSCBs (the right figure is a zoom in).

**Figure 20.**Experimental results for the system shown in Figure 12 when a capacitance of 240 $\mathsf{\mu}$F is added at the interface of the plug-and-play SSCBs, showing that the commutated current is reduced (the right figure is a zoom in).

**Figure 21.**(

**a**) Schematic and (

**b**) picture of the experimental setup connecting a constant voltage source to two constant current loads via lines in a meshed configuration.

**Figure 22.**Experimental results for the system shown in Figure 21, showing that selectivity is also achieved in meshed systems.

Parameter | Acronym | Value |
---|---|---|

Nominal voltage | ${U}_{\mathrm{nom}}$ | 350 V |

Nominal current | ${I}_{\mathrm{nom}}$ | 10 A |

On-state resistance per pole | ${R}_{CB}$ | 130 m$\mathsf{\Omega}$ |

Current limiting inductance | ${L}_{CB}$ | 1.0 $\mathsf{\mu}$H |

Maximum clearing time | ${t}_{\mathrm{max}}$ | 1.0 $\mathsf{\mu}$s |

Parameter | Acronym | Value |
---|---|---|

Nominal voltage | ${U}_{\mathrm{nom}}$ | 350 V |

Nominal current | ${I}_{\mathrm{nom}}$ | 10 A |

On-state resistance per pole | ${R}_{CB}$ | 130 m$\mathsf{\Omega}$ |

Current limiting inductance | ${L}_{CB}$ | 1.0 $\mathsf{\mu}$H |

Damper resistance | ${R}_{d}$ | 2.0 $\mathsf{\Omega}$ |

Damper capacitance | ${C}_{d}$ | 2.0 $\mathsf{\mu}$F |

Minimum clearing time | ${t}_{\mathrm{max}}$ | 1.0 $\mathsf{\mu}$s |

Overcurrent threshold | ${I}_{L,\mathrm{max}}$ | 20 A |

di/dt threshold | ${U}_{L,\mathrm{max}}$ | 20 V |

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

van der Blij, N.H.; Purgat, P.; Soeiro, T.B.; Ramirez-Elizondo, L.M.; Spaan, M.T.J.; Bauer, P.
Decentralized Plug-and-Play Protection Scheme for Low Voltage DC Grids. *Energies* **2020**, *13*, 3167.
https://doi.org/10.3390/en13123167

**AMA Style**

van der Blij NH, Purgat P, Soeiro TB, Ramirez-Elizondo LM, Spaan MTJ, Bauer P.
Decentralized Plug-and-Play Protection Scheme for Low Voltage DC Grids. *Energies*. 2020; 13(12):3167.
https://doi.org/10.3390/en13123167

**Chicago/Turabian Style**

van der Blij, Nils H., Pavel Purgat, Thiago B. Soeiro, Laura M. Ramirez-Elizondo, Matthijs T. J. Spaan, and Pavol Bauer.
2020. "Decentralized Plug-and-Play Protection Scheme for Low Voltage DC Grids" *Energies* 13, no. 12: 3167.
https://doi.org/10.3390/en13123167