Distribution Fault Anticipator (DFA)

Risk Reduction Category

Grid Monitoring

Technology Description

When conditions are favorable, namely dry fuels, low humidity, and high winds, all that is needed for a fire is an ignition heat source. When electric energy “escapes” the normal bounds of conductors and power delivery apparatus, often by some arcing mechanism, fire ignition is possible. The various ignition mechanisms can be characterized as follows.

  • Failure of a part or device such as a switch, clamp, or connector (e.g. arcing, heating, melting)
  • A downed arcing conductor
  • Explosion of apparatus such as transformers and capacitors
  • Clashing of conductors in the air
  • Arcing across conductors bridged by foreign objects (e.g. Mylar balloons)
  • Vegetation interference

Often there are multiple mechanisms in play. When a tree or branch falls and tears down powerlines, arcing may occur between multiple contacting conductors or between conductors to ground. Electrical arcing is the heat source, but the vegetation interference with powerlines is the true cause. Capacitor failures which create significant electrical transients can cause the failure of arrestors or connection devices at other very remote locations resulting in a distant fire ignition. Clearly, ignition from powerline causes is often a complex series of events [1].

If the incipient stage of a failing device or line fault can be detected and located, the final catastrophic failure may be avoided and a fire will not be ignited. No existing protection device or powerline monitoring system commonly used today can detect the incipient stage of a clamp or switch failure. However, it has been shown that waveform analytics applied in real time to high fidelity captures of the electrical signatures of failing devices can identify certain failures at an early stage, long before catastrophic failure [2]. By using the results of these analytic algorithms, coupled with other utility tools such as AMI, failures can often be found and fixed in a timely manner, thereby preventing a fire.

For more than a decade, researchers at Texas A&M University have conducted substantial research, funded primarily by EPRI and EPRI-member utilities to detect and anticipate incipient failures on distribution feeders using high-fidelity waveforms and sophisticated waveform analytics. [3] This work, which has become known as Distribution Fault Anticipation (DFA) technology, has identified signatures produced by failing equipment; external intrusions into power lines; and improper or unexpected feeder events, including fault-induced conductor slaps. In many cases, utility companies have used this newfound “awareness” of feeder conditions and events to locate and correct incipient failures before they could escalate and produce catastrophic damage [4].

The DFA consists of substation-based monitoring hardware and software, connected to available potential transformers (PTs) and current transformers (CTs) used for relaying and metering. A representation of the DFA system is shown in Figure 1 in the form of a data-processing hierarchy.

Figure 1: Data-processing hierarchy employed by DFA field devices[5]

Technical Readiness (Commercial Availability)

The DFA is commercially available from Power Solutions Incorporated.

https://powersolutionsllc.us/

Implementations / Deployments

There are roughly 1000 DFA deployments around the world. Principally in North America and some in Europe.

The DFA has been demonstrated for specific use cases, involving multiple utilities, with EPRI involvement. These use cases are listed below [5].

  • Event Category: Incipient Faults and Recurring Interruptions
    • Recurrent, Vegetation-Caused Breaker Operations
    • Recurrent Fault and Breached Lid of Service Transformer
    • Recurrent Fault Caused by Broken Strand in Long Span
    • Fault-Induced Conductor Slap
    • Feeder Lockout Cause by Fault-Induced Conductor Slap
  • Event Category: Line Switch and Clamp Failures
    • Failure of Line Switch
    • Failure of Hot-Line Clamp
  • Event Category: Capacitor Monitoring
    • Capacitor Restrike
    • Capacitor Switch Bounce
    • Capacitor Phase Failure

Innovations as of Mid 2023

Potential Enrichment Work Opportunity

References

[1] Russell, B. D., Benner, C. L., Wischkaemper, J. A., “Detection of Distribution Circuit Wildfire Ignition Mechanisms Using Substation-Only Sensors and Data Analytics” T&D World Wildfire Conference, December 8, 2020. [2] Wischkaemper, J. A., Benner, C. L., Russell, B. D., and Manivannan, K., “Application of Waveform Analytics for Improved Situational Awareness of Electric Distribution Feeders” IEEE Transactions on Smart Grid, vol. 6, pp. 2041-2049, 2015. [3] “Distribution Fault Anticipation: Phase III System Integration and Library Enhancement,” Final Report Prepared for the Electric Power Research Institute (EPRI), Document #1016036, Palo Alto, CA. July 2009. [4] Jeffrey A. Wischkaemper; Carl L. Benner; B. Don Russell; Karthick Muthu Manivannan, “Application of advanced electrical waveform monitoring and analytics for reduction of wildfire risk”, IEEE ISGT 2014. [5] “Automated Waveform Analytics for Improved Reliability and Operational Support: Demonstration of DFA Technology at Multiple Utility Companies”. EPRI, Palo Alto, CA: 2014. 3002004136.