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