Protocols driving smart grid interoperability


By Marlee Rosen, Rosen Associates

There is a dire need to transform the way we manage energy consumption, and smart grid initiatives are leading the way. Vendors and suppliers today are grappling with how to develop the proper communications and connectivity needed to implement smart grid and automated meter applications for electric, water and natural gas utilities.

One of the key principles of a smart grid is real-time, two-way communications between the consumer and the utility company. To enable this, a communications infrastructure needs to be rolled out but, before that can happen, there is a need to examine the different communications protocols to identify a few suitable ones that make the most sense. 

There are several emerging protocols like BACnet, LonWorks, DNP3, IEC and OPC that have already been adopted within various vertical industries like building automation, industrial automation and manufacturing industries, but today also seem to align well with the support of smart grid applications.  Industry standards, functional requirements, best practices, business policies, and reference designs and implementations are conjoining and becoming the basis for a "plug-and-work" architecture.

Planning for secure grid plug-ins

Today there is a need to establish a cohesive environment where equipment plugs in and goes to work. Interestingly enough, standard protocols and practices are needed not only to integrate intelligent equipment across a network but across several industries.  The need for standardization has become quite a tall order and one that is unprecedented on the scale that is envisioned today.  Those standards include the networking protocols as well as the "language" that will be used by the equipment.

According to the industry analyst firm Cambashi, communications protocols are crucial to the continuing secure and safe supply of utilities--especially energy. But ‘secure' in this context has two meanings: Both ‘reliable and consistent supply,' and ‘protected against attack.'

The more interconnected systems become, the more important it is to be sure there is no room for malicious--or even mischievous--interference with the network.  Utilities need to prioritize both aspects when choosing their protocol, as a failure in either can have serious consequences for the company and, more importantly, the customer.

The protocol race to the grid

The Distributed Network Protocol (DNP3) continues to be one of the most popular utility automation protocols in the United States. DNP3 is recognized in the IEEE 1379 standard for communications with intelligent electronic devices (IED) and is a viable smart grid protocol.

DNP3 differs from the more advanced IEC 61850 protocol in that it doesn't provide structured naming and complex object models. It's simpler in that it provides limited self-description of data, can be configured using XML, operates over the Internet protocol suite and has proven to be an extremely reliable protocol.  Additionally, IEC 61850 does not provide plug-and-play interoperability where DNP3 does.

Due to the belief that exorbitant costs will arise to secure hundreds or even thousands of remote devices, a lot of utility companies won't secure their SCADA systems. SCADA systems are on dedicated networks like that of PcVue which are difficult to hack, and since NERC (North American Electric Reliability Corporation) Critical Infrastructure Protection (CIP) standards do not require security for serial implementations, it has come to be that NERC has no jurisdiction in distribution, where there are many DNP3 deployments.

Protocol criteria and its challenges

Many believe that a smart grid network infrastructure needs to be IEC 61850-3 compliant to support interoperability and scalability, and it needs to be substation-hardened to withstand challenging environments in remote locations. IEC 61850 has become an international standard for communication in power generation facilities and substations. By integrating key functions within a substation, such as control, protection, measurement and monitoring, and by supporting high-speed protection applications, IEC 61850 is seen as an effective power management enabler and a viable smart grid protocol. 

The breakthrough timing protocol that offers, for the first time, sub-microsecond synchronization for clocks in various substation and power delivery devices such as sensors and actuators over an Ethernet network is IEEE 1588 v2.  It is a critical component for allowing utilities to offer the precision timing required to support the control algorithms required for modern power management and delivery systems. While sub-microsecond synchronization is valuable, increasing automation is likely to require synchronization at tens of nanoseconds rates in the near future. Equipment suppliers must develop, market and support the standards-based hardware and software required at that level of precision, based on the IEEE 1588 v2 standard.

About the Author
Marlee Rosen is a freelance writer/editor who has been working closely with NERC (North American Electric Reliability Corporation), a non-government organization that develops and enforces reliability standards.