In the evolution towards 100 % renewable electric power production, the objective of voltage control is to balance the voltage in future low voltage distribution grids connecting local loads and prosumers, as well as energy storage facilities. The aim is to stabilise the voltage as locally as possible, so that decisions and control commands can be issued as quickly as possible. Distributed voltage control is a challenging and demanding control application. Consumer devices rely on having stable voltage levels to operate successfully. When future energy networks rely on thousands of local energy generation units relying mostly on solar and wind power, then it is crucial to stabilise the voltage levels in all segments of the distribution grid. Inverters, or electronic power converters, measure the voltage and power and change the amount of power injected into the grid, and they connect and disconnect end points from the distribution network.
Distributed control means that the automated voltage control shall be performed by the local voltage control units based on local and neighbouring voltage and impedance values. Statistics and other information shall be communicated to the central distribution management system, though.
Use case one
Periodic communication service supporting message exchange for distributed voltage control.
A power distribution grid fault is a stressful situation. There are self-healing solutions for automated switching, fault isolation and, service restoration. Furthermore, these solutions are ideally suited to handle outages that affect critical power consumers, such as industrial plants or data centres. Supply interruptions must be fixed within less than a second for critical power consumers. Automated solutions are able to restore power supply within a few hundred milliseconds.
The FLISR (Fault Location, Isolation & Service Restoration) solution consists of switch controller devices which are especially designed for feeder automation applications that support the self-healing of power distribution grids with overhead lines. They serve as control units for reclosers and disconnectors in overhead line distribution grids.
The system is designed for using fully distributed, independent automated devices. The logic resides in each individual feeder automation controller located at the poles in the feeder level. Each feeder section has a controller device. Using peer-to-peer communication among the controller devices, the system operates autonomously without the need of a regional controller or control centre. However, all self-healing steps carried out will be reported immediately to the control centre to keep the grid status up-to-date. The controllers conduct self-healing of the distribution line in typically 500 ms by isolating the faults.
Peer-to-peer communication via IEC 61850 GOOSE (Generic Object Oriented Substation Event) messages provides data as fast as possible (Layer 2 multicast message). They are sent periodically (in steady state, with changing interval time in fault case) by each controller to several or all other controllers of the same feeder and are not acknowledged.
The data rate per controller is low in steady state, but GOOSE bursts with high data rate do occur, especially during fault situations. GOOSE messages are sent by several or all controller units of the feeder nearly at the same point in time during the fault location, isolation and service restoration procedure with a low end-to-end latency.
Use case #
Communication service availability: target value [%]
Communication service reliability: mean time between failures
End-to-end latency: maximum
Service bitrate: user experienced data rate
Message size [byte]
Transfer interval: target value
# of UEs
Service area (note 1)
1 (note 2)
< 5 ms
1 kbit/s (steady state) 1.5 Mbit/s (fault case)
< 60 s (steady state) ≥ 1 ms (fault case)
transfer interval (one frame loss)
Use case one
GOOSE (a)periodic deterministic communication service supporting bursty message exchange for fault location, isolation, and service restoration.