Protection in Power Systems aims to identify and isolate areas of the electrical network during a fault, so asto avoid dangerous situations for persons, irreparable damage to equipment and reduce the impact on the remaining healthy system.
The elements that consist a protection system are the following:
- Circuit breakers
- Current and voltage transformers
- Protection relays
- Communication infrastructure
- DC supply systems
Especially the protection relays are very important for detecting and restoring faults, as they are the “brain” of protecting schemes and they control the status of the breakers as the result of an internal measurement or comparison function.
The penetration of Distributed Generation (DG) and renewable energy sources in distribution networks can lead to failure of existing protection, as the direction of power flow and short circuit currents ceases to be unique since the contribution of DGs in faults could be significant. In order to study new protection problems arising, a laboratory adaptive protection system is being developed at NTUA as shown in the picture below.