Transcript Slide 1

Joint Grid Code Review Panel
POR Working Group
Meeting 2
27th March 2015
Chairperson : Michael Preston
Terms of Reference :
Scope of Working Group
It is proposed that a working group of the Joint Grid Code Review Panel be
established to:
• Develop an assessment methodology, to be used by the SOs, when deciding
whether a Generation Unit has complied with its required POR response,
under its HAS contract and relevant Grid Code.
• The assessment methodology should take account of the inertia effect.
• The assessment methodology will be proposed to the JGCRP for approval.
• If necessary modifications will be proposed to the relevant Grid Codes in
Ireland and Northern Ireland, as a result of this revised assessment
methodology.
Terms of Reference :
Scope of Working Group
It is proposed that a working group of the Joint Grid Code Review Panel be
established to:
•
Review Modification Proposal MPID 252 to the Ireland Grid Code, regarding
the definition of POR, and make a recommendation to the JGCRP regarding
this modification, or a revised version of this modification. Also review
consistency of this modification MPID 252, with the Northern Ireland Grid
Code and the ENTSO-E Network Codes, and make a recommendation to the
JGCRP on whether the Northern Ireland Grid Code requires any similar
modification with regard to the definition of POR.
Terms of Reference :
Scope of Working Group
• Review the declaration process for POR (currently EDIL) and comment on
whether this should be changed to more accurately reflect POR capability of
Generation Units, and if so investigate feasibility of implementing this (at a
high level) and associated benefits.
Action from GCRP :
In relation to MPID 265 Reactive Power : MP will assess the EDIL issue as part of the Scope of POR
Working Group.
Deliverables :
• Assessment methodology, to be used by the SOs, when deciding whether
a Generation Unit has complied with its required POR response, with
supporting documentation, technical justification, and worked examples.
Grid Code Modifications required, if any, in Ireland and Northern Ireland to
enable and/or support implementation of this assessment methodology.
• Recommendation regarding MPID 252 to the Ireland Grid Code: whether
this modification (or a specific revised version of MPID 252 should be
made to the Ireland Grid Code; whether a similar modification is required
to the Northern Ireland Grid Code.
• Recommendation on whether declaration process (EDIL) change should be
implemented for POR reserve and MVAr characteristics and if so include
high level feasibility, benefit analysis.
Unit delta output
0MW = average -60 to -30 sec pre-event
Frequency RH scale
LH scale
Primary Operating Reserve time period 5 to 15 seconds
Inertia only response from a non -governed steam turbine
7/1/15 event
Event start
T=0 sec @ 49.8 Hz
Nadir ≈3 sec
POR assessment @ 5 sec
Inertia only response from a non -governed steam turbine
7/1/15 event
≈ 4 MW being absorbed from the system due to +ve ROCOF
Inertia output 0 at nadir where RoCoF = 0
•
Only events with the nadir before 5 sec require inertia adjustment
•
Events with the nadir within 5 to 15 sec – normal assessment
Inertia only response from a non -governed steam turbine
7/1/15 event
Review of analysis
Limitations of methodology
•
The calculation method does not account for the generator and power system interactions that occur
immediately after a generation trip
•
The analysis initiates that the calculated inertia MW value is reasonably accurate at 5 secs which
is shortly after the frequency nadir with lower RoCoF values
•
The application of the calculation will require a tolerance for the MW value
Review of analysis
119
134
Review of analysis
Review of analysis
Review of analysis
Review of analysis
PMU analysis
PMU analysis
PMU analysis event 157
GI trip
PMU analysis event 164
GI trip
Proposed assessment method
• The issue arose from the current assessment method which requires the POR
assessment to be carried out at the lowest frequency during the POR period (5-15 secs)
• For events with the nadir before 5 secs the assessment was therefore carried
out at 5 secs
• The proposed change to the assessment method is to calculate the inertial
response of the synchronous generators as they react to the rising system
frequency at 5 secs and take the calculated power value into account when
determining POR performance
Existing assessment method
Nadir time within 5 -15 secs determined
POR assessed at lowest frequency during 5 – 15 sec period
Time of minimum frequency within 5 -15 secs period
Unit output limit with available capacity
Unit capacity limit
Unit output limit by sustained load capability
POR sustained load curve referenced at pre event unit output
Unit output corresponding to governor droop
Pre event frequency minus Nadir frequency ( = frequency delta)
Frequency delta with governor droop to calculate droop lift requirement at frequency nadir time
minimum
Unit output – pre event output
At NADIR time
POR requirement
POR achieved
POR tolerance 1 MW
minus
max
POR tolerance 10% of POR requirement
Fail if negative (reserve deficit after tolerance applied)
Proposed assessment method
•
Inertia MW value at 5 sec calculated from RoCoF and generator H value
•
RoCoF required from at least 100mS sampling rate source
•
Use Tandragee event recorder frequency source initially for all Island
•
Apply an error tolerance value to the inertia MW calculated value to increase
the calculated value
•
Tolerance value to be a % of the K value ?
• Either reduce POR requirement with inertia value
Or
• Increase POR achieved with inertia value
EDIL Reserve and Reactive
Reactive Capability Curves
EDIL declaration for Leading and Lagging at Max output
MW
MVAr leading
MVAr lagging
Reactive Capability Curves
EDIL declaration for range of points
MW
R
S
T
Q
P
MVAr leading
U
MVAr lagging
Reserve Curves
MW Reserve
EDIL declaration Maximum
MW output
Reserve Curves
EDIL declaration for range of points
MW Reserve
MW output
Reserve Curves
EDIL declaration for range of points
MW Reserve
MW output