Microgrid grounding protection solution

How to ground a microgrid?

Grounding of microgrids is one of the most challenging topics for microgrid protection. In grid-connected mode, the system grounding is generally provided by the substation transformer.

Why do we need a grounding system for a dc microgrid?

As this current has high value, it has to be interrupted to prevent the VSC from being damaged. The type of grounding system could also influence on safety, the ability to identify the fault, and survivability of DC microgrid under faulty conditions.

How do I ensure a ground source in a microgrid?

It is important to ensure that there is always a ground-source in any microgrid. In grid-isolated mode, this can be achieved by grounding the DER interconnecting transformers, or by providing a grounding transformer in microgrid, to cover the eventuality that interconnecting transformer (s) may be out of service.

What are the barriers to implementing a dc microgrid?

Although many efforts have been made to develop standards to facilitate implementation of DC microgrid, there is still a lack of practical standardisation on grounding systems for different voltage levels, cyber-security, and protection system. Proper protection of AC and DC microgrids is one of the last barriers for implementing microgrids.

What is microgrid protection?

An unfortunate fact is that microgrid protection largely focuses on shutting down inverter generation to protect the power electronics, rather than minimizing the outage area. New protection methods are needed that can operate with inverter-interfaced microgrids while providing protection coordination.

Why is a dc microgrid a multi-terminal protection system?

The topology of the DC microgrid is thus multi-terminal. And hence it becomes tricky to design a protection system flexible enough to deal with multiple numbers of terminals under a multi-directional power flow condition.