Capacitive Grounding for DC Distribution Grids with Multiple Grounding Points

Title

Capacitive Grounding for DC Distribution Grids with Multiple Grounding Points

 Author

Yañez Martinez, Kenji (TU Delft Applied Sciences; TU Delft Electrical Sustainable Energy)

Contributor

Ramirez Elizondo, Laura (mentor)
Mackay, Laurens (mentor)

Degree granting institution

Delft University of Technology

 Date

2017-08-28

 Abstract

DC Microgrids could play an important role in a renewable and sustainable future. Unfortunately, there are not enough standards or guidelines for the implementation of DC Microgrids or DC distribution grids in general. Nevertheless, reliability and security of such a system must be assured at all times. As a consequence, an important challenge lies in terms of protection.

This thesis project focuses on capacitive grounding and their respective ground fault detection and protection scheme for a general DC distribution grid. The protection scheme proposed aims to discriminate currents caused by load shifts from ground fault currents with as little communication between the protective relays as possible.

The safety requirements needed for a DC distribution system are analyzed and threshold values for current that may endanger the human body are derived from literature. A scheme using capacitive grounding is analyzed further through a sensitivity analysis for capacitor size. This analysis serves as a starting point to determine an important challenge for the discrimination of currents caused by load shifts and human faults. A detection scheme is proposed to differentiate these currents and demonstrated with Matlab Simulink.

An analysis showing the behavior of the system to increasing number of grounding points using this detection scheme is further discussed and studied by means of state space representation. This analysis helps as a starting point for the scalability of DC distribution systems with capacitive grounding.

 Subject

DC distribution grid
Capacitive Grounding
Multiple grounding points

 To reference this document use:

http://resolver.tudelft.nl/uuid:45d7d1c9-4a3c-4e7c-8047-7216438aeda0

 Embargo date

2018-09-01

 Part of collection

Student theses

 Document type

master thesis

 Rights

© 2017 Kenji Yañez Martinez
Files
PDF Report_fkyanez.pdf 4.72 MB
PDF CapacitiveGrounding_Mackay.pdf 740.92 KB
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