The transformation to a smarter and more intelligent grid is bringing new opportunities but also challenges in how utilities operate their businesses. Growing numbers of new devices, with wireless alongside wired, distributed intelligence and new services are all placing new demands on and requiring updated or new communications networks. For example, AT&T and Nokia are currently launching a private 4G LTE option for utilities at the field area network (FAN) level.
Another technology that is starting to gain interest in the energy sector is software defined networking (SDN), which had its origins in the need for an agile data centre network fabric connecting users to servers and storage dynamically in the cloud computing era.
In order to find out more about SDN, and to clarify some of the misconceptions around it, we sat down with Hansen Chan, product marketing manager of Nokia’s IP and Optical portfolio with special focus on vertical markets.
SDN for utilities
SDN is an evolution of the classic wide area network (WAN) model in which the control and data planes, rather than being integrated in a network element, are now physically separated. In SDN the control plane function resides in a centralized platform named the SDN controller, which also is equipped with an open application programming interface (API). In this way, the network becomes programmable, allowing other applications to programmatically control and monitor the network using the controller.
SDN network architecture
“The power of SDN is in the API as it enables rapid changes to the network connectivity and services to be synchronized and automated through the applications,” explains Chan. “In effect it converts the network from a static to dynamic state of operation.”
Promises of SDN
With the move to a smart grid, modern grid operations are becoming increasingly dynamic. In addition, dynamic network services are required to fully realize the benefits of cloud computing by being more responsive to bandwidth utilization.
Over and above the centralized network intelligence and optimization, SDN offers a number of other benefits to utilities, Chan continues.
These include the integration of multiple technologies (e.g. microwave, IP/MPLS or optical) and technologies from different vendors, and the enablement of a multi-tenant shared network through network slicing.
“The controller thus also plays a unifying role,” he comments.
In addition, it offers both enhanced network security and agile service automation and, importantly in the current utility IT environment, it can be cloud enabled.
SDN use cases
SDN can be implemented as an overlay to or an evolution from an existing WAN, depending on the use case requirements.
Chan identifies three example use cases: extending the network reach to microgrids – which has been tested in the Duke Energy OpenFMB microgrid demonstration – IT/OT integration through network slicing and real-time multi-layer network optimization. [Engerati-Duke Energy Microgrid Proves Interoperability]
As energy resources become more decentralized, microgrid deployment is becoming more prevalent, both in large facilities like corporate and college campuses, data centres and industrial plants, as well as in small residential communities. Utilities will need to expand their operational networks to reach all microgrids, which will require rapid provisioning and management of a large number of gateway routers.
An SDN operating over a private WAN network, service provider VPN or the internet would give the utility complete flexibility to reach the deployed microgrids, while retaining common provisioning and operational procedures.
The SDN automated provisioning and configuration management capability also allows the microgrid site connectivity to be provisioned readily without requiring a network specialist.
Up to now, IT and OT applications generally have been separately managed under different organizations and run over separate communications networks. A key initial step in the transition to IT/OT convergence is to integrate the respective networks into a common shared network while preserving each organization’s current operating practices. While some advanced network management systems allow multiple organizations to share a common network through the use of VPN technology and span of control capability, they fall short of empowering each organization to administer the network resources with full autonomy.
An SDN enables operators to virtually segment the integrated network into ‘slices’ for multiple organizations or ‘tenants’. Each organization owns a set of pre-assigned network assets such as an equipment port complete with full administrator privileges, thereby enabling them to retain their operation processes.
Applications in a modernized grid are becoming more bandwidth intensive as well as more dynamic. For instance, operation crews are equipped with tablets running applications such as geo-databases and video conferencing. During power restoration after storms, as crews access and exchange information, networks can experience a bandwidth surge in the affected areas.
Infrastructure SDN offers utilities an opportunity to dynamically direct traffic across the network to avoid congestion by using the path computation engine (PCE) in the SDN controller. When provided with full network service information as well as network-wide information, an SDN controller can monitor network key performance indicators such as packet loss and delay. When congestion is indicated, the SDN controller can compute new optimal paths for the affected services.
“By providing smarter end-to-end network control, automation and service agility, SDN rises to new operational challenges such as these,” says Chan in conclusion. “We believe SDN is a good strategy for utilities to follow on their modernization journey and that it will flourish in electricity markets.”