Substation Workshop

7th February 2018

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Agenda

• Welcome and Introductions – Antony White• Substation Design Overview – Andy Moore

Question & Answer Session

Break

• 1500kVA Transformers – James Devriendt & Andy MooreQuestion & Answer Session

• Close / Feedback – Antony White

Lunch 2

Andy MooreLead Design Engineer, LPN

Substation Design Overview

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UKPN Substation Design

• Ideal Scenario• Drivers behind the current policy• Substation Locations• Key Elements• Requirements for a basement location• UKPN’s preferred basement solution

4Applicable to all areas but predominately an LPN Area guidance

Ideal Scenario

Since 2011; UKPN’s stance regarding ‘new build’ developments has been: “The normal location for a substation, whether in a separate building or integral to a customer owned building, is at ground level”.

This is a similar stance to all other DNOs.

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Ground Level Location ~ Key Drivers

• 24hr unrestricted access~ OFGEM ‘KPI’: Customer Minutes Lost (CML).

• Manual Handling~ ‘Design-out’ MH of heavy plant wherever possible.

• Working at Height~ ‘Design-out’ WAH wherever possible (e.g. cable entry).

CDM – Designing out risk – installation, maintenance and de-commissioning

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Substation Location:GRP Enclosure

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EDS 07-3102_01 Unit or Padmount Substation in GRP Enclosure

Substation Location:Freestanding Brick

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EDS 07-3102_15 Freestanding Brick-Built Substation for a Transformer up to 1000kVA (Earth Ring)

Substation Location:Ground level Integral

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EDS 07-3102_20 Integral Substation for a Single Transformer up to 1000kVA

UKPN Substation Design

• Key Elements:• Plant Layout• Ventilation• Cable entry• Personnel access• Plant access

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UKPN Substation Design

Current requirements are detailed in the UKPN Engineering Design Standard:

‘EDS 07-3102 ~ Secondary Substation Civil Design’ & associated suite of drawings.

Available on the ‘G81’ section of the UKPN website.

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Substation Location:Basement

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EDS 07-3102_30 Basement Substation for a Single Transformer up to 1000kVA

When considering basement locations:• Maximum one level below ground floor• 24hr unrestricted UKPN staff access

– Without recourse to a third party (e.g. via Security Guard).– Dedicated ‘normal’ stairway (e.g. no ‘companionway’ ladders).– Dual-locking arrangements (if necessary).

• ‘Direct’ UKPN Plant Access– 24hr unrestricted.– Manual Handling kept to a minimum

• Natural Ventilation Scheme– Open to ‘free air’.– Passive ‘Stack’ principle employed.– Maintenance free. 13

24hr Unrestricted Personnel Access

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UKPN dedicated stairway >

< Access without 3rd party involvement

Direct Plant Access

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< Drop zone from above close to substation

< Minimising manual handling

Plant installation via running beam & hatch;

minimising manual handling >

Plant installation via running beam >

& Plant access hatch >

UKPN’s preferred basement solution: The ‘Lightwell’ substation

< Personnel access without 3rd party involvement

Via dedicated stairway >

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‘Lightwell’ substation cont’d:

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< Direct plant access via HIAB crane

Direct plant access with minimal manual handling >

Open to ‘free air’ ^Passive ‘stack’ principlesMaintenance free

When things go wrong - Simple

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When things go wrong - Complex

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Substation Design Summary:

Although we will always look for a ground level location in the first instance; UKPN will consider substations located in a basement.

A number of aspects need to be considered if we are to meet our own requirements in terms of Health & Safety and network security.

Each project requiring a substation will be assessed on its individual circumstances; providing the mandatory elements can be achieved.

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Answering your questions

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1500kVA Transformers

Connections Manager, SPN

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James Devriendt

& Andy MooreLead Design Engineer, LPN

Context• UK Power Networks charged with stimulating and supporting a

competitive market

• Market share has reduced significantly in majority of relevant market sectors

• Service delivery has demonstrably improved in recent years

• Appetite for more competitive offering is increasing

• Customers want UK Power Networks to be more flexible in offering

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Transformers

• 11kV transformer specification has typically been limited to 1MVA– Reduced unit diversity leads to lower unit cost and simpler

maintenance schedule

• Automatic loss of Connections market share to IDNOs, particularly in high land-value / physically constrained locations

• We have reviewed specification options with a number of customers to determine most useful offering

• 1500kVA unit with 2500A LV circuit breakers sourced24

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Current Status

• Asset Management have reviewed options

• Standard Drawings drafted• Engineering Bulletin issued for

comment (internally)• Relevant standards in the

process of being updated on G81

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Considerations

• Increased floor loading (compared to 1MVA)• Increased ventilation requirements (compared 1MVA)• ACB must be close coupled to the transformer (e.g. not wall

mounted)• 1m deep cable trenches required (due to close coupled ACB) and

bending radius requirements for 630mm singles• Customer installed back up generation would be strongly

recommended

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Uses

• Single connected customers (only) includes BNO, TBS and IDNO

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Outstanding ‘constraints’

• Basement locations currently not approved• GRP locations currently not approved• Refurbishments / upgrades out of scope

Current drawing

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Answering your questions

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Feedback & Thank you!

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