Czech DEMO - Island Operation successfully tested on 10kV level

CHP unit

Island operation in real network within Smart Region Vrchlabí (Demo5) was tested in June 2014 on 10 kV level with positive results.

The topic of islanding was selected to find a solution for areas prone to failures from point of view of both distribution system operator and climatic or geographical conditions (e.g. network with specific topology, local power generation or an area strongly influenced by climatic conditions – such as mountain areas).

Islanding in terms of Smart Region project is supposed to be tested on 10 kV and after the network unification also on 35 kV MV network in urban area Vrchlabí; the power supply during island operation is provided by the CHP unit (1.6 MW) connected within the island area. The aim of the island operation is to test the capability of predefined network to disconnect from surrounding MV grid in the case of failure on a superior level network and to keep balanced operation of the island.

Preconditions for successful Island operation are connection of sufficient power generating unit, operation of communication infrastructure and deployment of automation equipment. The equipment must be capable to undertake three subsequent tasks:

1) disconnect the predefined (island) area,

2) balance of production and consumption of the island during the failure duration and

3) re-connect the islanding area to the standard MV grid.

First successful island operation was launched when distribution grid was without power (black start). Second successful island operation was launched when the distribution grid was in normal operation by disconnection of the area of island operation by switch without interruption of power supply for customers in the islanding area – see picture below. Next step is to test island operation also on 35 kV level as soon as voltage unification in Vrchlabí is finished. Voltage and frequency power quality measurements during both island operation tests confirmed that EN 50160 standard was fulfilled and only not critical transient with short duration were observed when the island operation started.


  • Total duration of island operation: 4 hours
  • Power quality: EN 50160 fulfilled
  • CHP unit: suitable for island operation
  • Voltage and frequency measurement: not critical transient with short duration

Next steps:

1) Upgrade of a gas injection to the CHP for better dynamic behaviour during transients

2) Upgrade the CHP unit and distribution grid components for 35 kV level

3) Test island operation on 35 kV level

Launch of island operation in the case of power outage in superior distribution network

Picture: Launch of Island Operation in the case of power outage in superior distribution network – power outage was simulated by switch disconnection (10 kV level – voltage and frequency measurements)

Keywords: Islanding


  • CEZ

Share it

Related Media