Driven by IEC61850 and other Ethernet based communication protocols such as IEC 60870-5-104, switches have found their way into utility networks. Critical applications such as IEC61850 signals or SCADA data can be transmitted via Ethernet networks designed to be robust and reliable. Green field developments are an ideal opportunity to consider such solutions in substation and distribution communication networks.
The AFS650 and AFS670 Family offers many features which are required in the utility environments, including fast protection schemes, redundant power supply and alarm contacts, and enables the stepwise introduction of Smart Grid applications, such as integration of renewable energy sources, advanced distribution automation solutions and similar.
The AFS Family products are compliant to IEEE standards and enhance ABB’s product portfolio for distribution networks, Inplant communication and substation automation applications.
AFS Family at a Glance
−Fully managed modular switches
−Utility grade switches
- IEC61850 and IEEE1613 approved
- Extended temperature rating from -40°C up to 85°C (continuous) as an option
−19” or DIN rail mounting
−FE or GbE version available
−Fast protection scheme in case of link failure
−Automatic topology discovery using LLDP
−Local alarm indication (LED) and alarm contacts

Typical Topology
State of the art substation automation systems use the IEC61850 protocol for communication between IEDs (Intelligent Electronic Device), as well as from IEDs to the station control computer. The IEC61850 protocol transmits different signals, such as GOOSE messages (e.g. interlocking, trip, ...), Sampled Values and Client Server communication via an Ethernet network. Since these are mission critical services, the data packet should reach its receivers with highest security and minimum delay.
Communication networks applicable to substations based on IEC61850 require a network with high availability. Accordingly, the requirements for the communication network include beside IEC61850 specific features, fast network recovery time in case of link failures and high MTBF figures.
As communication equipment has to work in harsh electromagnetically polluted environments, mainly optical connections are used, with distances to be covered of maximum a few 100 meters.
Today’s SCADA Systems for distribution networks often use the IEC60870-5-104 protocol which is based on TCP/IP protocol stack.
The communication network for SCADA systems, which has to transmit real time and mission critical data, requires a redundant network topology and enhanced traffic engineering capabilities.
Besides SCADA data communication, distribution control centers have additional requirements. It might be necessary to provide a telephony system for operational purpose or channels for Renewable Energy (e.g. wind farms).
Since MV networks might be restricted to city areas or larger rural areas, the network design needs to be adapted as per actual requirements. Accordingly communication networks providing L2 Ethernet switching or L3 IP routing might be required. For installation in MV substations extended temperature range and immunity against EMC/EMI is required.
Distances to be overcome are typically in the range of a few kilometers.
Today’s In-plant applications require enhanced Ethernet communication functionality. Various services such as CCTV, public address or access control systems require communication with a central server or operator console.
In-plant communication refers to applications dealing with security of the infrastructure and recovery to normal operation after an incident. Therefore high availability of the communication network and high performance features are required.
Some of the In-Plant applications require significant bandwidth (e.g. CCTV), therefore a proper planning of the network for the initial and future expansion is needed.
To allow supervision and historical analysis it is necessary to synchronize end devices (e.g. cameras) from a central time server.
Product series classification and core parameters
(1) Classification logic and core differences
The AFS series is divided into two core product lines based on installation methods, port size, and functional expansion. Each sub model is precisely adapted to different scenario requirements:
Product series, sub models, installation methods, core structure, port configuration, power specifications, power consumption range, special functions
Compact AFS650/655 DIN rail (optional wall mounted) with fixed port design, metal casing with up to 10 ports (electrical/optical/SFP cage), including up to 3 GbE ports (electrical/SFP/combo) Low voltage: 18-60VDC; High voltage: 48-320VDC, 90-265VAC, supports redundant power supply 12-21W multi-mode/single-mode optical ports optional, suitable for small and medium-sized equipment access scenarios
Rack type AFS670/675 19 inch rack modular design (12 slots, 2 ports/module) up to 28 ports (electrical/optical/SFP cage), supporting FE/GbE, optical ports including SFP cage, SC, ST and other types of low voltage: 18-60VDC; High voltage: 77-300VDC, 90-265VAC, supports redundant power supply (spring clip or connector interface) 10-40W (no PoE), supports PoE power supply (only power type H/Z), high port density, suitable for multi device access in large substations