This will continue from the previous SYNAPS 1 project — the installation of the current sensors on LV feeders with known faults to determine their location. This work will focus on optimising the network calibration procedure and tuning the location technology to improve accuracy of the fault information and minimise the time required to generate it.
Objectives
Basic Fault Location
This will continue from the previous SYNAPS 1 project — the installation of the current sensors on LV feeders with known faults to determine their location. This work will focus on optimising the network calibration procedure and tuning the location technology to improve accuracy of the fault information and minimise the time required to generate it.
Once a fault is identified the equipment will be moved between feeder locations at regular intervals after liaison with UKPN. This will allow continued collection of fault data in multiple cable type environments. Fault location information will be communicated to asset teams for investigation and validation.
DNO Operational IT System Connection Specification
Development of a specification for an interface between the SYNAPS cloud server and DNO operational IT systems to enable DNO operational staff to be informed in real time when LV faults are detected on specific feeders and to provide fault location information when this is available. The target system will be determined through mutual discussion between the NIA partners and could include iHost or similar platform.
Advanced Fault Location
This will be based on around ten sets of the next generation SYNAPS sensors. These will be divided between SSEN and UKPN and the installation of the sensors will be on LV feeders with known faults and/or fault history. In addition to increasing the number of data collection sites, this work package will also aim to test and validate the technology in support of the following use cases:
- Low voltage networks that run in parallel known in the industry as fully meshed networks
- Long Term Fault Evolution. Investigation of the network disturbances noted in SYNAPS 1 project. to determine which are early faults, to follow their evolution into permanent faults, to seek to determine at what stage they can be located and to ascertain the scope for predicting the time before they become critical.
- Investigate if faults can be identified as either cable or joint faults.
Prototype DNO Operational IT System Connection
Based on the “DNO Operational IT System Connection specification” developed above, implementation and testing of a working interface between the SYNAPS system and the DNO Operational IT system.
Business as Usual Demonstration
A demonstration of the final TRL8 commercial prototype will be carried out on the distribution network with the intent to demonstrate the solution in a network environment and to evaluate the data connectivity.
Learnings
Outcomes
Success Criteria
SYNAPS 2 system locates faults on an LV network with a precision better than existing technologies.
The SYNAPS 1 & SYNAPS 2 NIA projects have demonstrated that the SYNAPS solution consistently detects, classifies and locates events (pre-fault events) before any other technologies such as reclosers and temporary fuses. Based on early event location SSEN repaired and recovered a section of cable. This fault location proved to be accurate following later independent forensic examination, by RINA, of a 5m cable joint. Project extension has been proposed, to continue advanced fault detection, classification and location in radial and meshed networks to capture additional similar outcomes.
Improve the accuracy of the fault position estimate with specific emphasis on calibration procedures.
Evidence that calibration assists in fault location analysis.
Improve the speed with which the location can be determined.
Currently it has improved from three weeks in SYNAPS 1 to less than 1 day in SYNAPS 2 during 2022. The model now provides instantaneous fault locations (subject to successful validation of models).
Validate the technology on a wider range of feeders and cable types, including fully meshed networks.
Technology installed on meshed networks at UK Power Networks. Technology validated in radial networks, validation on meshed networks in progress and location given for Greek St. Different cable types and network architectures covered. Enhanced calibration being investigated to improve fault locations on all types of networks.
Specify and demonstrate a basic interface between the SYNAPS 2 system and DNO IT systems.
Interface specified and agreed. Demonstration delayed due to resourcing, plan to be agreed regarding the interface with DNO IT Systems
Improve deployment procedures and expose more operational staff to the technology.
13 sites have been installed with SYNAPS 2 sensors, this involved calibration and commissioning processes.. DNO personnel, Fundamentals’ service personnel and third party (Freedom Group) personnel have been exposed to the technology.
Demonstrate installation on an operational meshed LV network.
Technology installed on meshed networks at UK Power Networks, six sites for 28 months.
Desirable Objective
Identify the fault as either cable (main cable or spur) and joint faults; RINA’s report provides evidence of joint faults. Faults can be identified in main cable, spurs or joints.
Investigate long term fault evolution on faulty cables (asset management: long term fault evolution at Trojan Way and Oakwood Close identified faults before a catastrophic breakdown had occurred). The early warning delivered by SYNAPS could help when determining the cause of a cable system fault which may otherwise be lost if a failure had occurred. This can also be used to inform future asset management planning.
Demonstration of the BAU commercial prototype on DNO network single feeder prototype for COPPsystem introduced at SSEN and UK Power Networks. Demonstrated space model at SSEN and UK Power Networks training centres in December 2022.
Fault Locations so Far
To date there been 13 fault locations modelled. Out of the fault locations modelled 11 have been successfully excavated and validated as the cause of the fault. These have been validated at RINA or by DNO Engineers. The location sites of these are below.
SSEN (radial):
- Trojan Way 2 locations excavated & verified (Rina report 2022-0117)
- Oakwood 3 locations excavated & verified (Rina 2023-0005)
- Penn Hill 1 location excavated & verified by SSEN.
- Rose Street Aberdeen 2 locations excavated & verified by SSEN.
- Rose Street 1 Location to be excavated.
- Sheldrake 1 Location to be excavated.
- Knowle Village being investigated.
UKPN (radial):
- Pelham 1 location verified, and cable rerouted due to tree route damage.
- McRae Lane 1 location identified. Excavation & repair carried out at this location due to permanent fault.
Lessons Learnt
Calibration Unit Failure: An issue was encountered with the operation of the original bespoke calibration unit when completing the SSEN installation. The calibration unit was returned to the manufacturer who modified the unit to offer a higher rating and extra protection that stops network fuses from tripping out. The key learning from this is that calibration work should have been tested on the PNDC test network before using on the DNO Network.
Uninterruptible power source for sensors: Fuse failure detection on a heavy fault on UK Power Networks network caused a fuse operation, but unfortunately the auxiliary power socket at the substation in this case, was downstream of the fuse, so the sending end sensor experienced a loss of power at the same moment. This issue has now been resolved and is an operational learning outcome for future installations. As a result of the protected mains source operational issue the installation procedure was improved to ensure an uninterruptible mains source is used, where available.
Fault Location Confirmation: Using complementary equipment such as Megger ‘Fault Sniffer 2’ non-intrusive gas tester, ‘Thermal imaging Observation techniques for Underground Cable Networks (TOUCAN)’ and EA Technology ‘ALVIN’ Reclose can confirm SYNAPS 2 pre-fault location improving asset management and cable health analysis. Identifying an accurate pre-fault location can be used to focus on early event identification impacting the performance and the reduction in location time after fuse/Alvin reclose operation.
Proactive Control Room: SSEN have created a Project Control Room team to learn how to model and interpret fault locations. This team also dispatch to fault locations, to enable operational staff to investigate and validate fault locations.
Third Party Validation: To validate that SYNAPS is capable of detecting faults at earlier stages than other types of fault monitoring equipment, RINA Technologies was used to examine joints that had not had any visible breakdown. Cable and joints were removed from the SSEN Oakwood substation based on SYNAPS fault location and low fault activity. This has proved to be a valuable exercise; without RINA Technologies the Project would not have been able to validate the fault on this installation.
