25 October 2012Gideon Evans
LV Network MonitoringDemonstrating thePossibilities
Introduction
• SSE’s Low Carbon homes
• Can LV Network Monitoring equipment be retrofitted without taking customers off supply?
Understanding the LV Network
• Capacity– Current– MDI Information– Demand and Generation– more informed decisions
• Performance– Voltage Limits– Power Factor– Power Quality / Harmonics– more informed decisions
Time
Capacity
Average Demand
XX:00 XX:30
Demand
Monitoring Equipment
MDIs
Measuring Current
Measuring Voltage
Transmission of data
Installing Equipment
Storage of data
Calculated data
Rezap
Fault management
Measuring Current
• Conventional CTs– Installation would require
disruptive substation works– Known choice
• Rogowski Sensors– Can be installed around
existing cable cores– Accuracy considerations
• Innovations– Sentec GRIDKEY current
transducer– Now on the market
Measuring Voltage
• Terminal Block Connection– Possible on modern fuse cabinets
(eg Lucy Trifca)– Constrained cable routing– Need to drill holes in enclosures?
• Direct Busbar connection– Requires work on live busbars– Connection leads need to be
routed away from operational area
• Innovations– Drummond G clamp– Now on the market
Data Aggregation
• Manufacturers offered integrated solutions– Current Group offered Open Grid product– GE offered a C650 Relay / RTU, designed to work with ENMAC– Selex Galileo offered their Sentec Gridkey product
• Early versions had limited functionality – They had difficulties with measurement of directional current and harmonics
• Communications– Aerial extensions were required
• Data Storage in the data aggregator– Issues with capacity and reliability
• Cabinets– Issues with size, weight, IP rating and mounting
Equipment Connection
Current Group Current Group Open Grid Open Grid
Harmonics
Real and Reactive Power
Chalvey Local s/s
Selex Galileo / Sentec - GridKey
Communications
• Modes of Operation– Streamed (Real Time measured data)– Half Hour (Calculated data)– Alarms (Un-solicited data)
• Protocol - DNP3– For use with existing SCADA based control systems– Standardised template was needed
• Storage– Pi Historian
Further investigation
• Streamline installation process? (Thames Valley Vision Project)
• Equipment life-cycle – what should we expect from manufacturers? (Thames Valley Vision Project)
• Total monitoring system accuracy?
• Monitoring systems’ own energy usage?
Key Learning Points
• Live retrofitting can be done
• Today’s equipment can monitor complex electrical parameters
• LV network is as unbalanced as we thought!
• Monitoring is a system. Comms and data storage are key features, not bolt on extras
• Manufacturers value access to DNO networks – help them to help you
Any questions?
Thank you