DNP3 Protocol Recommended For Pipeline, Gathering And Distribution Applications

February 2009 Vol. 236 No. 2

Philip Aubin, P.E., Control Microsystems, Ottawa, Ontario

The Distributed Network Protocol (DNP3) provides many advantages over conventional protocols in a wide range of natural gas applications including the monitoring and control of pipelines, gathering systems and distribution systems. Here are some key reasons why one should consider applying DNP3 for communications with pipeline remote devices.

(subhed)What Is DNP3?

DNP3 is a protocol that was developed to allow for flexible, secure communications between devices. It excels in telemetry applications, where requirements call for reliable communication with remote devices. These devices might include remote terminal units (RTUs), supervisory control and data acquisition (SCADA) systems, intelligent electronic devices (IEDs) and human-machine interfaces (HMIs).

(subhed)Layered Protocol

DNP3 is a layered protocol. Starting with the low-level physical communications, each layer adds functionality. The layered model allows DNP3 to be flexible, reliable, and standardized. Standard specifications at each layer make sure that equipment vendors can implement DNP3 protocols that can communication with each other. It is the unique functions and features of the DNP3 layers that lead directly to the benefits explained here that apply to gas transport applications.

(subhed)Earlier Protocols

There have been many open and proprietary protocols used in the architecture of gas transportation SCADA systems. In most cases these protocols are relatively simple in nature and lacking in the flexibility to provide secure, efficient and reliable data transfer.

(subhed)Origins Of DNP3

DNP3 was originally developed in the 1990s to support electrical distribution equipment. The needs of that business drove many features and functions of DNP3, such as support for object-oriented data, including meta-data; support for communication over long distances, including satellite systems; high levels of security; and interoperability with a variety of devices.

DNP3 was quickly adopted as a standard and a user group was formed in 1993. The protocol proved useful across a host of industries and is increasingly being adopted within the oil and gas industry. As an extensible protocol it continues to grow, allowing for new features to be created without impacting the underlying security and reliable communications capabilities.

(subhed)Conclusions

The DNP3 protocol offers major advantages over other protocols. These include standardization and interoperability, flexible communications with many options, security, strong support organization, room to grow and saves time and money. Here are some recommendations:

  1. Start with a decision to investigate how DNP3 can improve your pipeline operations.
  2. Lay out a specific plan for migration. Start small or with wholesale replacement. In either case, you should lay out a full plan for migration.
  3. Don’t simply replace the old communications devices with new ones. Consider the value that can be achieved by taking advantage of DNP3’s features. Be sure to consider remote configuration, standardized data structures, improved reporting, unsolicited event data, and adding security features.
  4. Join the DNP3 Users Group, to network with other users and to meet experienced suppliers.