Transcript CUSC changes to accommodate reactive power from

CUSC Amendment Proposal to Accommodate
Reactive Power from Wind Farms
BSSG
Wednesday 21st May 2008
Content

Background
 Drivers
for CUSC Amendment
 Issues with current drafting

Reactive Power from Wind Farms
 Current
definitions
 New definitions

Summary of proposed CUSC Amendments
Background

Grid Code CC6.3 already amended to incorporate
Reactive Capability requirements from Wind Farms

Corresponding changes are required in CUSC
(including MSA)

Successful CUSC Modification will allow:
 An
increased pool of Reactive Power providers
 Wind Farm Providers to be despatched and paid
BM Unit/ CCGT
Template for MSA (CUSC Schedule 2 Exhibit 4 and
associated text) record Reactive Capability at Generator
Stator Terminal and Commercial Boundary
BM Unit
Step Up
Transformer
Directly Connected Wind Farm in England and
Wales (using current definitions)
Power
Park
Units
Commercial
Boundary
Grid
Entry
Point
0.69/33kV
33/400kV
33kV
Recording information at
Generator Stator Terminal
and/or Commercial Boundary
not sensible
400kV
Grid Code CC 6.3 Reactive
Capability requirements at Grid
Entry Point (E&W). HV side of
transformer for Scotland or User
System Entry Point if embedded
Option 1 - Record Info at the Grid Entry Point
Power
Park
Units
Grid
Entry
Point
0.69/33kV
33/400kV
33kV
400kV
Would result in other changes to CUSC which refer to
capability for BM Units and CCGTs at Commercial Boundary


Would introduce inconsistent terms for different users
Option 2 – ‘Move’ the Commercial Boundary
Power
Park
Units
Commercial
Boundary
Commercial
Boundary
Grid
Entry
Point
0.69/33kV
33/400kV
33kV

400kV
CUSC allows this to be achieved in the site specific MSA
 Allows
for all types of connection to be accommodated
Current Definitions - Commercial Boundary
“(unless otherwise defined in the relevant MSA), the
commercial boundary between either The Company or a
Public Distribution System Operator (as the case may be)
and the User at the higher voltage terminal of the generator
step-up transformer;” CUSC Section 11

Not sensible to uniquely define the Commercial Boundary
for Power Parks in CUSC (variances across GB and site by
site reactive metering location)
 Proposed
solution - use the individual MSAs to document
where the Commercial Boundary will be (normally it will be
at the Grid Entry Point or User System Entry Point for
embedded)
Current Definitions - Generating Unit
“Unless otherwise provided in the Grid Code any apparatus
which produces Electricity”, CUSC Section 11

This definition leads to a solution at the individual turbine
level rather than at the Power Park Level

Changes to Grid Code definition would have other impacts
 Proposed
solution - any text in CUSC which refers to a
“Generating Unit” should be changed to “Generating Unit or
Power Park Module”
Directly Connected Wind farm in Scotland
Power
Park
Units
TO in Scotland
can own step up
transformer
Commercial
Boundary
0.69/33kV
33/400kV
33kV
Metering may be at LV
side of transformer
400kV
Grid Code CC 6.3 reactive
capability requirements at HV
side of transformer for Scotland
(User System Entry Point if
embedded).
New Definition – ‘Metered Point’

For some Power Parks the location of the reactive
metering is not at the Commercial Boundary

Therefore need to define the Metering location for
the purposes of the formula that convert Reactive
Capability from the meter to the Commercial
Boundary (if at different voltage level)
Again
due to site differences it is suggested that
this is uniquely defined in each MSA
Summary of Proposed CUSC Changes

Section 1: Applicability of Sections and Related
Agreements Structure
 Add

referencing to Power Park Modules
Section 4: Balancing Services
 Add
Referencing to Power Park Modules
 4.1.2.3 reference to new section for converting Reactive
Power between ‘Metered Point’ and Commercial
Boundary

Section 11: Definitions
 New
definition for ‘Metered Point’
Summary of Proposed CUSC Changes (Cont)

Schedule 3: Reactive Power
 Add
referencing to Power Park Modules
 Appendix 8 – new Part 3 to document formulae for
converting reactive power from ‘Metered Point’ to
Commercial Boundary

Schedule 2 Exhibit 4: MSA
 Site
specific Commercial Boundary for Wind Farms
 Location of ‘Metered Point’ (where appropriate)
 Appendix 1 – new Capability tables for Power Parks
Next Steps
BSSG comments/ feedback
 Proceed with CUSC Amendment Proposal
