Emerging Communications that Advance Distribution Automation

Authors: S. V. Achanta, K. Hao, and J. Fowler, Schweitzer Engineering Laboratories, Inc., USA

Distribution Automation (DA):  Power utilities are investing in new technologies across their operations and infrastructure. The fundamental objective for technology investments is to improve the efficiency of existing infrastructure. Some utilities are working on large initiatives to overhaul information technology/operation technology (IT/OT) network infrastructure and are building intelligence into their assets to support new and emerging applications.

With an increasing number of field devices capable of two-way communications, tremendous amounts of sensor and intelligent electronic device (IED) data are available. Utilities can use these data to continuously monitor the performance of assets to improve reliability and efficiency

Today’s active distribution networks need adaptive protection and control, automatic reconfiguration, advanced sensors and measurements, network management of apparatus, and two-way communications networks. DA is a system that enables electric utilities to monitor, coordinate, and operate distribution systems in real time from remote locations. Key drivers for DA include:

  • An increase in worldwide energy consumption
  • An increased emphasis by utilities on system efficiency, reliability, and quality
  • A focus on renewable energy and the integration of distributed energy resources (DERs) to reduce carbon footprints
  • The availability of real-time information and tools from field devices for faster decision-making

DA applications and control capabilities typically include:

  • Overload mitigation and load shedding
  • Cold-load pickup
  • Load reconfiguration and transfer
  • Fault location, isolation, and service restoration
  • Voltage regulation
  • Volt and volt-ampere reactive (VAR) control
  • Distributed generation control
  • Loss-of-source detection and open-phase detection
  • Miscoordination detection and mitigation

Emerging Communications

Existing DA architectures were developed using standards that satisfied specific requirements of centralized generation, transmission, and distribution systems. With the integration of DERs such as solar and wind farms, DA systems face a new set of communications requirements. To improve DA and leverage the capabilities of installed field IEDs and sensors, utilities must choose communications technologies that bind these devices together.

Therefore, it is important for utilities to understand the emerging communications technologies that are available for their needs and the communications systems requirements for their applications.

According to the National Institute of Standards and Technology (NIST) Framework and Road Map for Smart Grid Interoperability, the communications network for distribution power systems is known as the field-area network (FAN). This network is dedicated to DA and the integration of DERs. A FAN allows utilities to communicate with DA devices such as IEDs, voltage regulators, capacitor banks, sensors, faulted circuit indicators (FCIs), and remotely operated switches, as well as a large array of newer technologies such as DERs and microgrids.

Some utilities have two or more independent networks. For example, a utility might have one network used for DA and one advanced metering infrastructure network used for smart meters installed at residential and small commercial locations.

Each of these networks relies on different mechanisms to backhaul its aggregated data to a common data control center. Instead of expanding and maintaining these separate networks, it would be helpful to utilities if the next generation of FANs integrates these networks so that end devices can exchange data more seamlessly. This integration would provide many communications system benefits, such as bandwidth efficiency, latency, reliability, and security.

There are essentially two types of FANs: low latency networks, which support time-stringent applications such as teleprotection, and latency-tolerant networks, which do not have stringent latency requirements.

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