A Distribution Network Operator’sView of Connecting Microgeneration

Simon Roberts and Dan Wells

For RegenSW - South Devon College

07 September 2011

Introduction (1)

• Scottish and Southern Energy: Company Overview

• The way we distribute electricity: 400kV to 230V

• Other activities: “The Low Carbon Challenge”

• DNO - Compliance with Legislation

• Some Interesting Numbers

• Our Stakeholders

• Supplier is King

Then it’s Dan’s turn

Introduction (2)• The Application Process

– G83 Stage 1;

– G83 Stage 2 and

– G59

• Electrical issues

• Other Considerations

• Connection Agreements and Export MPANs

• How much does it cost?

• The SEPD Team and Contact Details

• Where to get more information

• Questions, Answers, and your Feedback

• Paper Copies of the Slides

Scottish and Southern Energy plcOur business – and some of the things we do with energy:

• Energy Trading

• Energy Generation

• Energy Storage

• Energy Supply

• Energy Services

• Energy Transmission

• Energy Distribution

Southern Electric Power Distribution (SEPD):

What we do:

Our first priority is to provide a safe and reliablesupply of electricity to our domestic, commercialand industrial customers.

It is our responsibility to maintain, repair andimprove our electricity network - keeping thelights on

We are required to investigate any complaintsassociated with quality of supply and to rectifydeficiencies including, as a last resort, thedisconnection of nuisance loads and generation.

Southern Electric Power Distribution (SEPD)Where we do it:

Generation

In the olddays, it allcame frominstallationslike this:

Electricity Transmission and Distribution

NGT / SEPDSubstation atMannington,Dorset

400kV - 132kV

How we do it:

Distribution (1)

Wareham

Substation

132kV - 33kV

How we do it:

Distribution (2)

WinterborneKingston

Primary Substation

33kV - 11kV

How we do it:

Distribution (3)

WinterborneWhitechurch No.2Pole MountedSubstation (200kVA)

11kV - 230 / 400v

3 wire HV

3 phase LV

Note: the three LVfuse handles on thetallest pole

How we do it:

Distribution (4)

A 3-wire HV mainline with 2 phasesconnected to theprimary winding of a25kVA transformer.

The LV is connectedas 3-wire (2 phasesand a neutral)230/460V: note the 2LV fuse handles onthe pole.

How we do it:

Distribution (5)

LV “mains”overhead line

Aerial BundledConductor (ABC)

How we do it:

Distribution – end of the line

Single Phase Cutout

230 volts single phaseFused at 100 amps

Which phase:Red or Yellow or Blue?Brown or Black or Grey?

How we do it:

Distribution – the end of the line? Not quite

Because then there’s

Distributed Generation

2.3kW of PV on the roof

How we do it:

Low Carbon Challenge for DNOs– the “big ticket items”

• Smart grids with supply sidemanagement

• Active network management

• Getting ready for electric vehicles

• Connection of distributed generation atall voltage levels

“D” CodeLicence

ESQCR

• Licence: Duties, Responsibilities, Performance, Finance• Distribution Code: Engineering Specifications• ESQCR: Safety and Quality Standards

DNO – Compliance with Legislation

Our Stakeholders

• End user Customers

• DG Installers and Manufacturers

• Builders and Developers

• Housing Associations

• Local Authorities

• Schools and Colleges

• Electricity Suppliers

• Metering Businesses

• Independent Connection Providers

• Independent DNOs

• Industry Regulator – Ofgem

The Principle of the “Supplier Hub”

Simplified version:

Supplier

Hub

DistributorMeter Operator

Data Collector

Data Aggregator

Customer

Transmission

System

Operator

Connection Application Process (1)

• We can connect all your DG, but there may be acost and it can take time

• The performance standards for processing DGconnection applications are:

– 65 working days for HV and EHV connections

– 45 working days for LV connections

• Two formal documents published by the EnergyNetworks Association and approved by OFGEM

– G83/1-1 (Stage I and Stage2) (June 2008)

– G59/2-1 (April 2011)

G83 (Stage 1, < 16 amps/phase) Install and Notify

For: micro CHP; micro PV; micro FC;

micro WIND and micro HYDRO

This translates (230V x 16A) into 3.68kW We round thisto 3.7kW)

Installers have 30 days from commissioning to informDNOs of these single installations on the relevantnotification form.

Charges: Nil charge

G83 (Stage 2 - Multiple Installations)

G83 Multiple Installations (<16 amps per phase,3.7kW): Customer or their Installer must applyfor connection before starting work. SEPDapplication form available on our website(www.ssepd.co.uk).

Charges: NIL charge for up to 6 installations of<4kW (i.e. part G59) each at the same fullpostcode location providing the installationsare balanced across all 3 electricity phases andNIL physical reinforcement works required,otherwise individual charges will apply.

G59/2-1 Generation

G59 is an industry standard for generators greater than16A per phase

• Up to 50kW there is a provision for type testedequipment similar to G83; however

• G59 connection applications must be submitted forsystem studies and associated network reinforcementwhere necessary prior to connection.

Charges: Individual charges will apply and will dependon the work carried out to complete network studies andreinforcement. We may wish to witness thecommissioning of DG > 30kW for which we charge a fee.

Help us to help you:

Take care to fill in the correct application form

Send notifications and applications by email andinclude, where possible:

• Google satellite views of the location / roof /field

• Photographs of the building, HV and LVoverhead lines, pole mounted transformer andLV fuses, transformer name plate, cutout andmeter position.

Application information – really nice to have (1)

Place cursor on property; right click; select “what’s here” to creategreen arrow; Ctrl-Alt-Print Screen; paste into email or attachment.

Application information – really nice to have (2)

Place cursor on property; right click; select “what’s here” tocreate yellow arrow; Ctrl-Alt-Print Screen; paste into emailor attachment.

Application information – really nice to have (3)

Application information – really nice to have (4)

Single Phase Domestic Three Phase Industrial

Electrical Issues (1)

G83 Protection: not sufficient to prevent overvoltages,

but does protect generation:

Over volts: 264 volts, disconnect in 1.5 seconds

Under volts: 207 volts, disconnect in 1.5 seconds

Over frequency: 50.5 Hz, disconnect in 0.5 seconds

Under frequency: 47 Hz, disconnect in 0.5 seconds

Loss of mains: disconnect in 0.5 seconds

G59 protection: two stage approach - see handout for

the values

Electrical Issues (2)

• SSEGs nuisance tripping (overvolts): export tends toincrease voltage profile on LV network, especially underlow load conditions.

• SSEGs nuisance tripping (undervolts): due to transientdisturbances on the HV system.

• Short Circuit Levels: especially from electro-magneticinduction generation - can add significant contribution tofault level

• Reverse power flow: need for care not to exceed thermalrating of DNO equipment

• Voltage unbalance: need to balance generation acrossall phases, in the same way as load.

• HV voltage control: serious impact from significantSSEG connections on the LV network

More on Voltage Rise

• Existing DNO networks were designed with“tapered” cross-section cable systems whichare not suited to the connection of distributedgeneration

• The LV network was designed for a thermalrating and voltage drop for a domestic load of2kVA ADMD, with NIL export

• Secondary substations (11kV – 230/400 V) are“tapped” to the highest possible no-loadvoltage output of 253 volts. Can only beadjusted off-load.

Other Considerations:

• Planning consents – particularly for overheadlines

• Land rights – wayleaves, easements, andstatutory rights

• Clustering – overloading one location

Topics not covered today:

• Different types of loss of mains (LoM)protection

• Neutral Voltage Displacement (NVD), OverCurrent, Earth Fault and Reverse Powerprotection

• Islanding

• System Security and Stability

• Earthing

• HV Generating Plant

• DC Injection; Harmonics; Voltage flicker, etc

Generation Connection Agreements (1)

Less than 30kW Installation

Standard Connection Agreement, forms part of thecustomer’s retail contract with their EnergySupplier. No action required by the Customer,Installer or DNO.

Customer has the option of “deemed” or “metered”export. If export is to be metered, then an exportMPAN will be required. MPANs can be obtained viathe Energy Supplier (D0168 dataflow request to theDNO) or direct from the DNO. Energy Suppliers areresponsible for arranging the installation of themeter and subsequent readings.

Generation Connection Agreements (2)

More than 30kW installation

An Embedded Generation ConnectionAgreement is required. This is a “significant”legal document which includes information onboth import and export restrictions.

This Agreement requires to be signed by theGenerator Owner and DNO prior to issue of anexport MPAN. The MPAN can be obtained fromthe Energy Supplier or direct from the DNO.

Generation Connection Agreements (3)

Parallel Running Agreement:

Required by Generators using “Standby Sets”for own use. Occasionally run in parallel withDNO network for short periods (e.g. 5 minuteseach month) for synchronising supplies only.Very important for DNOs to know thegeneration technical details for fault levelsecurity.

How to contact the SEPD team:

For MPANs starting with 20…………..

<50kW: south.microgen@sse.com

Tel: 01202 784835

>50kW: mcc@sse.com

Tel: 01738 456723

MPANs - for all DNOs (first 2 numbers):

11.......... Central Networks (East Midlands)

12……... UKPN (London)

13……… Scottish Power (Manweb)

14……… Central Networks (West Midlands)

15……… CE Electric (NEDL)

16……… Electricity North West

17……… Scottish Hydro Electric Power Distribution

18……… Scottish Power (South of Scotland)

19……… UKPN (Seeboard)

20……… Southern Electric Power Distribution

21……… WPD (South Wales)

22……… WPD (South West England)

23……… CE Electric (YEDL)

XX……... Independent Distribution Network Operators

Must get: FREE GUIDES

From the Energy Networks Association:

Distributed Generation Connection Guides

• G83/1-1 Stage1 (SSEG single installations)

• G83/1-1 Stage 2 (SSEG multiple installations)

• G59/2 (all other generation)

• Available to download on-line at:www.energynetworks.org

Must get: Engineering Recommendations

From the Energy Networks Association:

• Distributed Generation Engineering Recommendations:

• G83/1-1 (SSEG installations)

• G59/2 (all other generation installations)

• Available to order on-line at: www.energynetworks.org

Cost: just under £100 each (and worth every penny)

A DNO’s view of connecting Microgeneration

Questions

Answers

Feedback