2023 Fibersense

FiberSense – DigitalAsset™️: Protecting High Voltage Underground Assets

Synopsis

TransGrid, an Australian electricity network, implemented FiberSense DigitalAsset™ in order to enhance the safety of a crucial 330kV underground cable. By utilizing FiberSense's capabilities for 24/7 cable monitoring and real-time alerts, TransGrid is able to receive early warning of potential physical threats to the cable.

Prior to the implementation of FiberSense, TransGrid relied on daily patrols for inspection, which proved to be both time-consuming and costly.

With the integration of FiberSense DigitalAsset, TransGrid was able to reduce patrols by two-thirds, conducting them only twice a week. The solution is provided as a service, providing constant monitoring of critical linear power assets in an urban environment, enabling TransGrid to redirect routine patrols to other areas and swiftly dispatch them to specific locations upon the detection of an event.

Snapshot

Company Name(s): FiberSense, Transgrid
Company Website: www.fibersense.com
Technology Category: Encroachment, Software, Mapping, Locating
Stakeholder Target Audience: Facility Owner, Project Owner
Key terms /phrases: DigitalAsset™️, sensing, strike detection, software as a service, sensing as a service
Level of Production:
[in full production and available for purchase]

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Background Benefits Threat of Interference Summary Quotes

Background

TransGrid is an Australian electricity network that extends throughout New South Wales and the Australian Capital Territory, with connections to Queensland and Victoria. It forms the backbone of the Australian National Energy Market (NEM) and enables trading between Australia’s three largest states along the east coast. In space-constrained areas of the transmission network, underground cables are used, and are generally buried under roadways. Their location makes them highly susceptible to external interference from road construction works. This is exacerbated by the common deployment of their high voltage cables adjacent to other critical infrastructure including water, gas, and telecoms.

Even though Transgrid’s routine maintenance regimes are reviewed annually, the consequences of failure on its primary assets could be catastrophic, directly impacting on Australia’s economy. Repairs on Transgrid’s underground cables take considerable time and cost. One example given is a cable damage due to external interference that took five months to repair and cost approximately $5 million AUD to restore.[1]

To improve its safety posture, Transgrid deployed FiberSense’s DigitalAsset™ service on a critical 330kV underground cable supplying the Sydney Central Business District. Delivered as a software-as-a-service offering, FiberSense DigitalAsset™️ runs along the fiber optic cable adjacent to Transgrid’s underground assets and using patented acoustic sensing can detect threats to the cable such as unauthorized digging events and tampering.

[1] Transgrid Underground Cables Renewal and Maintenance Strategy 2020/2021 - https://www.aer.gov.au/system/files/Transgrid%20-%20Underground%20Cables%20Renewal%20and%20Maintenan...

Figure 1 — Transgrid Map (not full FiberSense Coverage)

Tangible benefits by case study participants

Benefits realized by Transgrid:

24/7 cable monitoring protecting multiple assets
Early warning of threat events to avoid risks
Targeted vehicle patrols to halt risky works
Audit trail of cable activity for damages recovery
Significant cost savings and operational efficiency
Immediate cable fault location

The Threat of External Interference to Underground Cables

Construction contractors using excavators, boring machines, and jackhammers on road surfaces pose a significantly higher threat to the integrity of the underground cables than any internal failure. An immediate strike can cause electricity outages, disruptive repairs, brand damage, and of course, injury or death to workers. Damage that does not result in an immediate fault can result in future cable failure, offering little recourse for cost recovery from the contractor.

Transgrid categorizes external interference as a major threat to its underground network. Route patrols are in place to mitigate this risk of interference and represent the greatest routine inspection and maintenance expenditure in underground cables. In an environment where funding is becoming further constrained, these inspections are continually being questioned.

In addition to this, route patrols have provided a false sense of security because it is a non-continuous solution to protecting the underground network. Threat activity between patrols is a common shortcoming as well as threats that may be unseen from the surface but put the network asset at risk. Cost comparisons of replacing periodic patrols with effective continuous monitoring are frequently challenged by underestimating the fundamental difference in the quality and effectiveness from continuous threat detection monitoring replacing periodic surface observation.

Jeffree Cairns is Transgrid’s Transmission Lines & Cables Asset Strategist and explains, “A damaged cable is a serious problem that we plan to avoid using a number of strategies. Vehicle patrols offer some protection for our cables, but they are expensive and can’t cover all areas, all the time. Our commitment to safety and network reliability demanded a more robust system.”

The FiberSense DigitalAsset™ service was deployed along 28.1 kilometers (17.4 miles) of high-voltage cable in the Sydney metro area in April 2020. The vibration detection and ranging (VID+R) technology continually monitors the length of dark fiber, then locates and identifies any vibration strain with an accuracy of ± 5 meters (16 feet) along the asset. The single dark fiber with the DigitalAsset™ service protects multiple linear assets in the vicinity.

The DigitalAsset™ platform identifies activity through the fiber cable that classifies the threats by severity and nature (e.g., mechanical digging). From their customized client portal, Transgrid network operators review notifications from DigitalAsset™ and confirm action.

The portal overlays registered activity from the national Dial Before You Dig service, which means that Transgrid can quickly get in touch with construction contractors in the area and dispatch patrols to stop work and prevent outages. The ability to monitor for activity in known and unknown work zones allows for prioritized dispatch of interdiction teams to any event outside of a marked sector.

The technology has enabled Transgrid to significantly reduce costly vehicle patrols by two thirds,[2] to two days a week, while increasing the security coverage across the entire cable length, allowing patrol services to be better utilized.

The FiberSense client portal provides a GPS mapped view of the entire monitored asset. When network operators receive a real-time early warning notice from the portal, they know precisely where to direct their patrol, removing the guesswork and providing time to intervene.

[2] Transgrid Underground Cables Renewal and Maintenance Strategy 2020/2021 - https://www.aer.gov.au/system/files/Transgrid%20-%20Underground%20Cables%20Renewal%20and%20Maintenance%20Strategy%20-%2030%20Nov%202021%20-%20PUBLIC.pdf

_{Figure 2 — FiberSense Portal (sample screenshots)}
_{Figure 2 — FiberSense Portal (sample screenshots)}

Machine Learning (ML) algorithms continually improve the accuracy of the models by automatically learning and improving from the gathered data across the global FiberSense network. This helps to reduce the number of false positives, allowing the model to accurately identify different threats and categorize accordingly, distinguishing between vibrations caused by excavation activity, as opposed to a non-threatening event.

Historical faults have left a legacy of losses and downtime for operators, which Transgrid expects to avoid with its DigitalAsset™ monitoring service. Previously, fault detection and location was a time-consuming and complex process that often required extensive testing and significant repair work, which could further stress the cable insulation. This made it challenging to efficiently identify and fix faults in the system.

With DigitalAsset™, calibration tests are automatically conducted, saving time when locating faults. Unplanned repairs due to faults or damage pose a serious inconvenience to the utility. What’s more, cable faults can eventuate several years after a mechanical strike. With the construction contractor long gone, and no record of past activity, cost recovery becomes almost impossible.

Summary

By implementing FiberSense DigitalAsset™️, Transgrid was able to reduce vehicle patrols on its network by two thirds and provide 24/7/365 monitoring on critical linear power assets in an urban environment. Transgrid intends to broaden the scope and implementation of FiberSense to other paths to further increase situational awareness of its infrastructure and improve network efficiency.

Quotes

All quotes attributable to
JEFFREE CAIRNS
TRANSMISSION LINES & CABLES ASSET STRATEGIST
TRANSGRID

“A damaged cable is a serious problem that we plan to avoid using a number of strategies. Vehicle patrols offer some protection for our cables, but they are expensive and can’t cover all areas, all the time. Our commitment to safety and network reliability demanded a more robust system.”

“Our asset and close surroundings are essentially being scanned for threats 2,500 times per second. We simply couldn’t achieve that level of security without FiberSense technology.”

“Our risk mitigation actions are responsive to the level of assessed threat. With more insights at our fingertips, we can be smarter about allocating our resources to where they’re needed most.”

“If we can’t avoid damage, then we want to achieve the fastest return to service possible and allocate the costs to those responsible. DigitalAsset’s monitoring will give us the audit trail we need.”