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Design drivers for monitoring critical infrastructure

  1. Monitoring of Electricity Substations Steve Braithwaite CEng, MIET,SMIEEE Founder/CTO of ASH Wireless ASH Wireless is an electronics design consultancy Specialising in wireless and sensors
  2. Monitoring of Electricity Substations • The Project: • Monitoring required to characterise substation loading • Ofgem Network Innovation project • Over 500 substations • Intro to the Ofgem project ....
  3. 3 An Ofgem funded Network Innovation Competition project
  4. 4 The problem Assets have nominal thermal rating Ratings = OC Ratings K amps Diverse range of environments Small changes in environmental factors can result in very different actual ratings HV network LV network Assumed thermal ratings can lead to capacity being under-utilised or unnecessary risk Objective is to maximise power through transformer
  5. 5 Celsius as part of the smart future Celsius monitoring Smart meter data Thermal Ratings Tool Reinforce Retrofit cooling Extra capacity Lower bills for customers
  6. 6 Partners and roles on project Facilitate customer focus groups Develop customer communication materials Lead the customer survey engagement Analyse trial data Develop methodologies to understand relationship between asset temperature, load characteristics and surrounding environment Determine impact of cooling technologies Develop tool and spec for low cost temperature sensor Recommendations for BAU rollout Supply complete retrofit monitoring solution Provide ongoing support throughout installation, commissioning and operation of the retrofit thermal monitoring workstream Peer review of the analysis methodology of the retrofit temperature sensor part of the project An investigative study on the impact of Celsius on the lifetime health of network assets Work with ASH, Ricardo-AEA and Electricity North West to develop retrofit thermal monitoring solution Participate in evaluation and selection of retrofit cooling techniques
  7. 7 Celsius £5.5 million Investment Up to £583m across GB by 2050 Financial benefits Awarded: 9th December 2015 Go live Monitoring installation Mar 2017 Monitoring trial Mar 2018 Thermal ratings tool stage 1 Oct 2018 Retrofit cooling installation Jun 2018 Cooling trial Jun 2019 Thermal ratings tool stage 2 Jan 2020 Closedown Mar 2020
  8. 8 Step 1: Fit thermal monitoring Internal temperature Asset Environmental factors External temperature Thermal coefficient Learning Thermal Ratings Tool Deliverable More capacity Benefit
  9. 9 Step 2: Retrofit cooling Retrofit cooling Internal temperature Asset Environmental factors External temperature Full capacity Benefit Enhanced Thermal Ratings Tool Deliverable Retrofit cooling specifications, installation methodologies and buy order Learning
  10. 10 Monitoring site selection and timescales To enable trials to take place during all seasons and to trial all cooling techniques Four year project Subset of 520 substations – enough sites to adequately trial all techniques 100 cooling technique sites Enough substations to represent 80% of GB substation population 520 substations
  11. 11 Site selection map
  12. 12 Celsius technology Hub Wireless sensor
  13. 13 Celsius technology – trial fit LV board with three sensors
  14. 14 Celsius technology – trial fit Transformer
  15. 15 Trial site data -5 0 5 10 15 20 25 30 35 -20 0 20 40 60 80 100 120 140 30/09/2016 00:00 30/09/2016 12:00 01/10/2016 00:00 01/10/2016 12:00 02/10/2016 00:00 02/10/2016 12:00 TemperatureDegreesC RealPowerkWperPhase Magda Rd 750kVA Transformer Load and Temperatures P1 kW P2 kW P3 kW Top Oil oC Inlet oC Outlet oC Bottom Oil oC
  16. An urban substation (Magda Rd, Stockport) The solution design is often driven not by - the sensing technology - the data transmission - the back end data analysis But …..the installation
  17. Defining a Solution The solution design is often driven not by - the sensing technology - the data transmission - the back end data analysis But …..the installation
  18. 18 Legacy Assets  A significant percentage of electrical substations are more than half a century old  Most are not installed with measurement equipment for voltage, current, power, power quality, temperature of key assets  Critical infrastructure – any work must not intrude on continued operation.  Access to the sites is restricted for safety reasons
  19. 19 ?How to fit monitoring sensors when…  No internet connection available  No mains power available  Can’t install wiring, mount equipment, etc without intruding on critical operations  Interesting RF environment for radio connections,, multipath, multiple monitoring points needed
  20. KeLVN - Design Requirements  Monitoring system can be installed non-invasively;  All equipment magnetic or cable-tie mounting;  All equipment battery powered for duration of data gathering project (3.5 years).  All equipment wireless, only leads are those required to actually take measurements.  Daily reports to back end. 30 minute measurements of V, I, P, Q, THD, Temperature
  21. Backhaul Choices • Clusters of sensors over a small area • Spread over a large part of the country • Mobile network is clear winner • LPWAN • Possible, but patchy network support • 2.5G GPRS chosen • Coverage, component cost
  22. Local Wireless Sensor Network • Requirement for large substations (30m x 15m), sensors may be in cabinets • Path loss at 2.4GHz expected less than 90dB • Avoid stationary nulls by using antenna diversity • Energy-efficient 802.15.4 transceivers used, no front- end-modules • Operation needs to allow for more than one hub • Large coverage • Check installation from outside the substation
  23. Local Wireless Sensor Network • Simple, non-paired network access, minimised energy • Sensors transmit the last 6 hours of measurements (1 packet) every 30s • Time-jittered to avoid multiple collisions from time- aligned sensors • A hub listens for 60s for reports every 6 hours • Hub transmits a daily report to a back-end database • Hub operates for 3.5 years on a Lithium D-cell • Other sensors use AA or D cells for >3.5 year life
  24. TT T T Voltage Sensor Temperature Sensor GPRS Backhaul Mobile data link Hub 1 Hub 2 (optional) Hex 1 PMU Hex 2 Ind. V,I,T Low Power Radio Network Single Temperature Sensors Back End KeLVN - Substation Monitoring
  25. Battery Life • The Hub is an interesting challenge: • Lithium D-cell, 10AH • Over 3.5 years life • Distribution of where the capacity is used: KeLVN Hub battery usage Daily GPRS data transfer Sensor receiver window Quiescent: ‘off’
  26. Key learning points • The installation and environment defines • Equipment design (e.g. magnetic mounting) • Protocol (e.g. multiple hubs allowed) • installation procedure (fast, non-invasive) • GPRS modem auto-connect modes are not reliable, process needs detailed design • Alarms • Not required in Celsius • Low latency for alarms is managed with a hub software extension, and external power to the hub
  27. Example of how legacy assets can be made to yield valuable data Retrofitting monitoring equipment to legacy assets: • Ease of installation is primary consideration • Use of a local wireless sensor network eases installation • Optimise air interface to manage trade off between latency, data rate, battery life

Editor's Notes

  1. 2 Installation Elements, each followed by an analysis of data. The first being an Installation of retrofit monitoring followed by analysis of data and design of a Thermal ratings tool The second trial will be installation of various different cooling techniques, followed by analysis of benefits and this will feed into developing and refining the thermal ratings tool
  2. Mention Hotstick installation