5 Next Generation Networks: Innovation in Grid Connection and Storage, Steve Gough

Innovation in Grid Connection and Storage

Steven Gough

Innovation & Low Carbon Networks

Engineer

Agenda

1) Introducing Network Planning and Constraints

• Limitations influencing Generation

• Security of Supply

2) Alternative Connections

• Timed

• Soft-Intertrip

• Active Network Management

3) Storage


Western Power Distribution DG Levels


Western Power Distribution DG Levels

• 7.8 Million Customers

• 55,000 sq km area

• 216,000 kms of linear assets

• 184,000 substations

• DG Capacity Connected up to Q3 2014 – MVA

• DG Connected March to September 2014 – MVA

• DG Capacity Offered and Accepted – MVA


4,100

640

8,800

What Influences Generation Connections?

Main technical barriers:

I. Power flow, thermal rating and losses

II. Voltage management (static and dynamic)

III. Fault level

IV. Power quality

V. Protection

VI. System issues for National Grid

Transient stability

exporting Grid Supply Points

balancing, etc.

VII. Security of Supply – ENA Engineering Recommendation P2/6


Curtailment for Standard Connections?

Generation connected under firm arrangements will have a resilient

supply, however the majority of DG is connected under non-firm

arrangements, so when the network is running abnormally, the

generation may need to be switched off.

Typically this occurs due to:

• Unplanned faults (transient, short-term and long term)

• Planned maintenance

• Planned new construction works

• Planned asset replacement

The duration of the abnormal running depends on the criticality of

the event and will range from milliseconds to months


TIMED

• Generation curtailed

within specific times

• Sub 1MVA

• Modelled seasonal capacity variations

• Localised control only

• No comms

• May have for voltage constraint

• Non-optimised

SOFT-INTERTRIP

• Releases pre-fault

capacity with trip

facility

• 11kV and 33kV

• Real-time monitored values

• Small clusters of generation or simple pinch points

• Existing monitoring with localised control

ACTIVE NETWORK MANAGEMENT

• Fully optimises capacity

based on all constraints

• Management of generation using LIFO principles

• Real-time granular control of output

• Requires new Active Network Management control and monitoring systems

Costs, Complexity & Network Optimisation

1010

1011

0100


Alternative Connections

Standard Connection Conventional connection (with CAF, where

applicable)

Traditionally all connection agreements have been in a single

format.

Alternative Connections can also be connected under three

additional commercial arrangements.

Enduring Alternative Connection Alternative connection (no CAF)

Interim Alternative Connection Alternative until reinforcement complete (CAF)

Part Standard, Part Alternative Increase capacity of existing standard

connection with additional Alternative capacity

top up


Alternative Connections

Trade-offs between Alternative Connections and

Conventional Reinforcement

Up Front Cost Ongoing Cost

Timed connections Low Curtailment (fixed by timed

restrictions, i.e. 11.3%)

Soft intertrip Medium Curtailment (depending on

et ork o ditio s, a d su -

opti al )

ANM Medium Curtailment (depending on

et ork o ditio s, opti al curtailment)

Capacity-based subscription fee

Conventional Reinforcement High / Medium / Low None

All o e tio s desig ed as o -fir ill e s it hed off for a or al ru i g


Estimating Curtailment

WPD uses historical

load data on its

network models and

superimposes

idealised generation

profiles to estimate

the level of

curtailment

experienced by the

connections


Solar Storage Description

• Techno-economic trial of a real battery energy storage system on

a large solar ge erator s side of the eter, i “o erset. • Quantify benefits for both the DNO and Customer with real data.

• WPD South West & 2 other project partners:

• What will be the benefits of generator connected storage?

• Generator earnings and project viability.

• Network management services.

• Explore routes to market – challenges and rewards.

• Making the case for energy storage in new connection offers.


System schematic


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MVA

Business Challenges

• High demand for renewables connections in the South West.

• Renewable generation does not match peak local demand.

• ‘e e a le ge eratio has high ra p rates a d is ery `spikey . • Network capacity built for worst case scenarios and operated

within conservative limits.

• Power quality management is not currently provided by

renewables operators (other than specifying a power factor).

• No way of preventing race conditions without extra equipment.

Storage has been calculated to offer £60k/MVA/year of benefits to

distribution networks alone - how can these benefits be made

commercially realisable by DNOs?


Benefits split into 9 Usage cases


Usage Case. Beneficiary

1) Sell electricity for a higher price per kWh Owner

2) Shape generation profile to demand. DNO

3) Peak lop network demand (by exporting). DNO

4) Raise minimum demand to limit voltage rise. DNO

5) Voltage control. DNO

6) Peak lop generation to build bigger solar parks. Owner

7) Smoothing / Power Quality. DNO

8) Change peak lopping level (glass ceiling). DNO

9) Constructive system interactions DNO

DNO Limitations

• DNOs are required to maintain the network

• They are not allow to trade energy

• Battery vs conventional reinforcement

• When done for a connection we are obliged to offer the least

cost scheme

• Current governance limits the situations when we would be

able to use storage


Commercial Arrangements - economic upsides.

• On the customer side there are few limitations

• There is more access to other markets and revenue streams

• STOR

• Balancing (SSP spikes and demand customer SBP spikes)

• Triad payments (TNUoS)

• Significant reduction in connection costs if reinforcement

avoided.

• There is potential for commercial arrangements directly with the

DNO too (e.g. GDUoS)

• Real power network support (both import and export).

• Reactive power network support


Thank you


www.westernpowerinnovation.co.uk

[email protected]

Technology

5 Next Generation Networks: Innovation in Grid Connection and Storage, Steve Gough