MONTHLY CONSTRAINT
REPORT - JUNE 2016
FOR THE NATIONAL ELECTRICITY MARKET
PUBLISHED JULY 2016
IMPORTANT NOTICE
MONTHLY CONSTRAINT REPORT
IMPORTANT NOTICE
Purpose
AEMO has prepared this document to provide information about constraint equation performance and related
issues, as at the date of publication.
Disclaimer
This document or the information in it may be subsequently updated or amended. This document does not
constitute legal or business advice, and should not be relied on as a substitute for obtaining detailed advice about
the National Electricity Law, the National Electricity Rules, or any other applicable laws, procedures or policies.
AEMO has made every effort to ensure the quality of the information in this document but cannot guarantee its
accuracy or completeness.
Accordingly, to the maximum extent permitted by law, AEMO and its officers, employees and consultants involved
in the preparation of this document:
 make no representation or warranty, express or implied, as to the currency, accuracy, reliability or
completeness of the information in this document; and
 are not liable (whether by reason of negligence or otherwise) for any statements or representations in this
document, or any omissions from it, or for any use or reliance on the information in it.
Copyright 2016. Australian Energy Market Operator Limited. The material in this publication may be used in
accordance with the copyright permissions on AEMO’s website.
Page 2 of 13
introduction
© AEMO July 2016
MONTHLY CONSTRAINT REPORT
CONTENTS
IMPORTANT NOTICE
2
1. INTRODUCTION
4
2. CONSTRAINT EQUATION PERFORMANCE
4
2.1.
2.2.
2.3.
2.4.
2.5.
2.6.
2.7.
2.8.
2.9.
4
4
5
6
7
7
8
9
10
Top 10 binding constraint equations
Top 10 Market impact constraint equations
Top 10 violating constraint equations
Top 10 binding interconnector limit setters
Constraint Automation Usage
Binding Dispatch Hours
Binding Constraint Equations by Limit Type
Market Impact Comparison
Pre-dispatch RHS Accuracy
3. GENERATOR / TRANSMISSION CHANGES
3.1.
12
Constraint Equation Changes
12
TABLES
Table 2-1 – Top 10 binding network constraint equations
Table 2-2 – Top 10 market impact network constraint equations
Table 2-3 – Top 10 violating constraint equations
Table 2-4 – Reasons for Top 10 violating constraint equations
Table 2-5 – Top 10 binding interconnector limit setters
Table 2-6 – Non-Real-Time Constraint Automation usage
Table 2-7 – Top 10 largest Dispatch / Pre-dispatch differences
Table 3-1 – Generator and transmission changes
4
5
5
6
6
7
10
12
FIGURES
Figure 2-1 — Interconnector binding dispatch hours
Figure 2-2 — Regional binding dispatch hours
Figure 2-3 — Binding by limit type
Figure 2-4 — Market Impact comparison
Figure 3-1 — Constraint equation changes
Figure 3-2 — Constraint equation changes per month compared to previous two years
© AEMO July 2016
8
8
9
10
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Contents
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MONTHLY CONSTRAINT REPORT
1. INTRODUCTION
This report details constraint equation performance and transmission congestion related issues for June 2016.
Included are investigations of violating constraint equations, usage of the constraint automation and performance of
Pre-dispatch constraint equations. Transmission and generation changes are also detailed along with the number
of constraint equation changes.
2. CONSTRAINT EQUATION PERFORMANCE
2.1. Top 10 binding constraint equations
A constraint equation is binding when the power system flows managed by it have reached the applicable thermal
or stability limit or the constraint equation is setting a Frequency Control Ancillary Service (FCAS) requirement.
Normally there is one constraint equation setting the FCAS requirement for each of the eight services at any time.
This leads to many more hours of binding for FCAS constraint equations - as such these have been excluded from
the following table.
Table 2-1 – Top 10 binding network constraint equations
Constraint Equation ID
Description
(System Normal Bold)
Q>NIL_BI_FB
S-STTX_SNWF
N_X_MBTE2_B
Out= Nil, H8 Boyne Island feeder bushing (FB) limit on Calliope
River to Boyne Island 132kV lines, for the contingent loss of a single
Calliope River to Boyne Island 132kV line, Feedback
Out = Snowtown 132/33kV TX or Snowtown CB4593 or Snowtown
CB6265, limit for Snowtown WF generation of 0 MW
Out= two Directlink cables, Qld to NSW limit
#DIs
(Hours)
3711
Change
Date
03/12/2013
(309.25)
1459
16/01/2015
(121.58)
1079
25/11/2013
(89.91)
V::S_NIL_TBSE
S>>KHKN_SETB_SGKH
V>>V_NIL_2A_R
NSA_Q_BARCALDN
V>>S_NIL_SETB_SGKH
S_LB3_0
Out = Nil; Vic to SA Transient Stability limit for loss of one of the
Tailembend-South East 275kV lines (South East Capacitor
Available).
893
Out = Keith - Kincraig 132 kV line; avoid O/L of Snuggery - Keith
132kV line on trip of either South East - Tailem Bend 275 kV line
(64.0)
Out = Nil, avoid pre-contingent O/L of South Morang F2 500/330kV
transformer, radial mode, YWPS unit 1 on 500kV, feedback
(48.08)
Network Support Agreement for Barcaldine GT to meet local
islanded demand for the planned outage of 7153 T71 Clermont to
H15 Lilyvale or 7154 T72 Barcaldine to T71 Clermont 132kV line
Out= Nil, avoid O/L Snuggery - Keith 132 kV on trip of South East Tailem Bend one 275kV line, Feedback
Discretionary upper limit for Lake Bonney 3 generation of 0 MW
16/07/2015
(74.41)
768
577
560
18/06/2014
21/06/2016
06/05/2015
(46.66)
524
31/05/2016
(43.66)
471
21/08/2013
(39.25)
V>>S_KNPW_SETB_SGK
H
Out= Kincraig - Penola West 132kV line, avoid O/L Snuggery - Keith
132kV on trip of one South East - Tailem Bend 275kV line, Feedback
429
08/10/2013
(35.75)
2.2. Top 10 Market impact constraint equations
Binding constraint equations affect electricity market pricing. The relative importance of binding constraints are
determined by their market impacts.
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© AEMO July 2016
MONTHLY CONSTRAINT REPORT
The market impact of a constraint is derived by summarising the marginal value for each dispatch interval (DI) from
the marginal constraint cost (MCC) re-run1 over the period considered. The marginal value is a mathematical term
for the market impact arising from relaxing the RHS of a binding constraint by one MW. As the market clears each
DI, the market impact is measured in $/MW/DI.
The market impact in $/MW/DI is a relative comparison but not otherwise a meaningful measure. However, it can
be converted to $/MWh by dividing the market impact by 12 (as there are 12 DIs per hour). This value of
congestion is still only a proxy (and always an upper bound) of the value per MW of congestion over the period
calculated; any change to the limits (RHS) may cause other constraints to bind almost immediately after.
Table 2-2 – Top 10 market impact network constraint equations
Constraint Equation ID
Description
(System Normal Bold)
∑ Marginal
Values
Change
Date
Q>NIL_BI_FB
Out= Nil, H8 Boyne Island feeder bushing (FB) limit on Calliope
River to Boyne Island 132kV lines, for the contingent loss of a
single Calliope River to Boyne Island 132kV line, Feedback
839,922
03/12/2013
S-STTX_SNWF
Out = Snowtown 132/33kV TX or Snowtown CB4593 or
Snowtown CB6265, limit for Snowtown WF generation of 0 MW
254,873
16/01/2015
T_MRWF_QLIM_7
Out = NIL, limit Musselroe Wind Farm to 140 MW if less than 4
capacitor banks available. Swamped if 4 capacitor banks
available
141,246
08/12/2014
N_NYNGANSF_010
Nyngan Solar Farm upper limit of 10 MW
122,337
13/05/2016
V>>S_KNPW_SETB_SGK
H
Out= Kincraig - Penola West 132kV line, avoid O/L Snuggery Keith 132kV on trip of one South East - Tailem Bend 275kV line,
Feedback
104,787
08/10/2013
F_MAIN+NIL_DYN_RRE
G
Mainland Raise Regulation Requirement, Feedback in Dispatch,
increase by 60 MW for each 1s of time error below -1.5s,
Basslink unable transfer FCAS
88,084
21/08/2013
N_NYNGANSF_051
Nyngan Solar Farm upper limit of 51 MW (50% capacity)
76,972
14/06/2016
F_I+NIL_DYN_RREG
NEM Raise Regulation Requirement, Feedback in Dispatch,
increase by 60 MW for each 1s of time error below -1.5s
61,327
21/08/2013
V>SMLBAHO4
Out = Ballarat to Horsham or Bendigo to Kerang line, avoid O/L
Buronga to Redcliffs (0X1) line for trip of Bendigo to Kerang, or
Ballarat to Horsham line
52,982
24/11/2015
S_LB3_0
Discretionary upper limit for Lake Bonney 3 generation of 0 MW
50,327
21/08/2013
2.3. Top 10 violating constraint equations
A constraint equation is violating when NEMDE is unable to dispatch the entities on the left-hand side (LHS) so the
summated LHS value is less than or equal to, or greater than or equal to, the right-hand side (RHS) value
(depending on the mathematical operator selected for the constraint equation). The following table includes the
FCAS constraint equations. Reasons for the violations are covered in 2.3.1.
Table 2-3 – Top 10 violating constraint equations
Constraint Equation ID
Description
(System Normal Bold)
Q>NIL_BI_FB
Out= Nil, H8 Boyne Island feeder bushing (FB) limit on Calliope
River to Boyne Island 132kV lines, for the contingent loss of a single
Calliope River to Boyne Island 132kV line, Feedback
#DIs
(Hours)
58
Change
Date
03/12/2013
(4.83)
__________________________________________________
1 The MCC re-run relaxes any violating constraint equations and constraint equations with a marginal value equal to the
constraint equation’s violation penalty factor (CVP) x market price cap (MPC). The calculation caps the marginal value in each
DI at the MPC value valid on that date. MPC is increased annually on 1st July.
© AEMO July 2016
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MONTHLY CONSTRAINT REPORT
Constraint Equation ID
Description
#DIs
(Hours)
(System Normal Bold)
NSA_Q_BARCALDN
F_T+RREG_0050
F_T+LREG_0050
F_T+NIL_MG_R6
F_T+NIL_WF_TG_R6
Network Support Agreement for Barcaldine GT to meet local
islanded demand for the planned outage of 7153 T71 Clermont to
H15 Lilyvale or 7154 T72 Barcaldine to T71 Clermont 132kV line
18
Change
Date
06/05/2015
(1.5)
Tasmania Raise Regulation Requirement greater than 50 MW,
Basslink unable to transfer FCAS
(0.91)
11
Tasmania Lower Regulation Requirement greater than 50 MW,
Basslink unable to transfer FCAS
(0.83)
10
Out = Nil, Raise 6 sec requirement for a Tasmania Generation Event
(both largest MW output and inertia), Basslink unable to transfer
FCAS
(0.41)
5
Out= Nil, Tasmania Raise 6 sec requirement for loss of a Smithton to
Woolnorth or Norwood to Scotsdale tee Derby line, Basslink unable
to transfer FCAS
(0.41)
5
29/01/2015
29/01/2015
12/04/2016
12/04/2016
2.3.1. Reasons for constraint equation violations
Table 2-4 – Reasons for Top 10 violating constraint equations
Constraint Equation ID
Description
(System Normal Bold)
Q>NIL_BI_FB
Constraint equation violated for 58 non-consecutive DIs during the month. Max violation of 95.23
MW occurred on 17/06/2016 at 0715 hrs. Constraint equation violated due to Gladstone units
being limited by their ramp down rate.
NSA_Q_BARCALDN
Constraint equation violated for 18 non-consecutive DIs during the month. Max violation of 17.39
MW occurred on 07/06/2016 at 0655 hrs. Constraint equation violated due to Barcaldine unit was
limited by its start-up profile.
F_T+RREG_0050
Constraint equation violated for 11 non-consecutive DIs during the month. Max violation of 50
MW occurred on 07/06/2016 at 0235 hrs and 09/06/2016 at 1525 hrs. Constraint equation
violated due to Tasmania raise regulation service availability less than requirement.
F_T+LREG_0050
Constraint equation violated for 10 non-consecutive DIs during the month. Max violation of 50
MW occurred on 07/06/2016 at 0235 hrs and 09/06/2016 at 1525 hrs. Constraint equation
violated due to Tasmania lower regulation service availability less than requirement.
F_T+NIL_MG_R6
Constraint equation violated for 5 DIs during the month. Max violation of 43.69 MW occurred on
07/06/2016 at 2215 hrs. Constraint equation violated due to Tasmania raise 6 sec service
availability less than requirement.
F_T+NIL_WF_TG_R6
Constraint equation violated for 5 DIs during the month. Max violation of 32.32 MW occurred on
08/06/2016 at 1200 hrs. Constraint equation violated due to the same reason as
F_T+NIL_MG_R6.
2.4. Top 10 binding interconnector limit setters
Binding constraint equations can set the interconnector limits for each of the interconnectors on the constraint
equation left-hand side (LHS). Table 2-5 lists the top (by binding hours) interconnector limit setters for all the
interconnectors in the NEM and for each direction on that interconnector.
Table 2-5 – Top 10 binding interconnector limit setters
Constraint Equation ID
(System Normal Bold)
N_X_MBTE2_B
V::S_NIL_TBSE
Page 6 of 13
Interconnec
tor
Description
N-Q-MNSP1
Import
Out= two Directlink cables, Qld to NSW limit
V-SA Export
Out = Nil; Vic to SA Transient Stability limit for loss of
one of the Tailembend-South East 275kV lines (South
East Capacitor Available).
#DIs
(Hours)
Average
Limit
(Max)
1079
-93.52
(89.92)
(-132.8)
883
510.17
(73.58)
(569.07)
© AEMO July 2016
MONTHLY CONSTRAINT REPORT
Constraint Equation ID
(System Normal Bold)
F_MAIN++APD_TL_L5
S>>KHKN_SETB_SGKH
Interconnec
tor
Description
T-V-MNSP1
Import
Out = Nil, Lower 5 min Service Requirement for a
Mainland Network Event-loss of APD potlines due to
undervoltage following a fault on MOPS-HYTS-APD
500 kV line, Basslink able to transfer FCAS
844
146.06
(70.33)
(50.47)
Out = Keith - Kincraig 132 kV line; avoid O/L of
Snuggery - Keith 132kV line on trip of either South
East - Tailem Bend 275 kV line
722
372.66
(60.17)
(508.25)
Out = Nil, avoid pre-contingent O/L of South Morang
F2 500/330kV transformer, radial mode, YWPS unit 1
on 500kV, feedback
559
967.69
(46.58)
(1310.44)
Out = Nil, avoid pre-contingent O/L of South Morang
F2 500/330kV transformer, radial mode, YWPS unit 1
on 500kV, feedback
557
20.63
(46.42)
(-267.8)
Out = Nil, avoid pre-contingent O/L of South Morang
F2 500/330kV transformer, radial mode, YWPS unit 1
on 500kV, feedback
545
173.94
(45.42)
(419.47)
Out = Nil, avoid pre-contingent O/L of South Morang
F2 500/330kV transformer, radial mode, YWPS unit 1
on 500kV, feedback
522
-113.18
(43.5)
(219.27)
Out= Nil, avoid O/L Snuggery - Keith 132 kV on trip of
South East - Tailem Bend one 275kV line, Feedback
506
252.07
(42.17)
(470.08)
Out= Kincraig - Penola West 132kV line, avoid O/L
Snuggery - Keith 132kV on trip of one South East Tailem Bend 275kV line, Feedback
417
128.84
(34.75)
(406.72)
V-SA Export
V>>V_NIL_2A_R
VIC1-NSW1
Export
V>>V_NIL_2A_R
V-SA Import
V>>V_NIL_2A_R
T-V-MNSP1
Export
V>>V_NIL_2A_R
V-S-MNSP1
Export
V>>S_NIL_SETB_SGKH
V-SA Export
V>>S_KNPW_SETB_SGK
H
V-SA Export
#DIs
(Hours)
Average
Limit
(Max)
2.5. Constraint Automation Usage
The constraint automation is an application in AEMO’s energy management system (EMS) which generates
thermal overload constraint equations based on the current or planned state of the power system. It is currently
used by on-line staff to create thermal overload constraint equations for power system conditions where there were
no existing constraint equations or the existing constraint equations did not operate correctly.
The following section details the reason for each invocation of the non-real time constraint automation constraint
sets and the results of AEMO’s investigation into each case.
Table 2-6 – Non-Real-Time Constraint Automation usage
Constraint Set ID
Date Time
Reason(s) for use
CA_SPS_4667C455
06/06/2016 18:55 to
06/06/2016 19:05
Constraint Automation. Constraint set was created to manage Hazelwood A2
transformer on trip of Hazelwood A1 transformer during uncommon system
configuration. Constraint Automation revoked after system configuration
returned to normal.
2.5.1. Further Investigation
CA_SPS_4667C455: Investigated and no constraint equation changes required. This occurred due to a unique
system configuration which is unlikely to occur again.
2.6. Binding Dispatch Hours
This section examines the number of hours of binding constraint equations on each interconnector and by region.
The results are further categorized into five types: system normal, outage, FCAS (both outage and system normal),
constraint automation and quick constraints.
In the following graph the export binding hours are indicated as positive numbers and import with negative values.
© AEMO July 2016
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MONTHLY CONSTRAINT REPORT
Figure 2-1 — Interconnector binding dispatch hours
400
Quick
300
139
Constraint
Automation
Hours Binding
200
37
100
FCAS
176
122
96
53
0
-25
-13
-100
-100
-200
-13
N-Q-MNSP1
-22
-48
-13
Outage
-50
-110
NSW1-QLD1
System
Normal
T-V-MNSP1
V-S-MNSP1
V-SA
VIC1-NSW1
The regional comparison graph below uses the same categories as in Figure 2-1 as well as non-conformance,
network support agreement and ramping. Constraint equations that cross a region boundary are allocated to the
sending end region. Global FCAS covers both global and mainland requirements.
Figure 2-2 — Regional binding dispatch hours
Hours Binding
800
700
Ramping
600
NSA
500
Constraint
Automation
25
400
Non Conformance
720
20
300
78
FCAS
426
200
330
Outage
246
252
100
115
System Normal
26
0
NSW
Qld
SA
Tas
Vic
Global FCAS
Misc
2.7. Binding Constraint Equations by Limit Type
The following pie charts show the percentage of dispatch intervals in June 2016 that the different types of
constraint equations bound.
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© AEMO July 2016
MONTHLY CONSTRAINT REPORT
Figure 2-3 — Binding by limit type
Unit Zero - FCAS
0%
Unit Zero
14%
Voltage Stability
2%
Discretionary
2%
Transient Stability
9%
FCAS
39%
Interconnector Zero
1%
Thermal
26%
Ramping
0%
Quick
2%
Outage Ramping
0%
Other
0%
Network Support
3%
Non-Conformance
1%
Oscillatory Stability
0%
2.8. Market Impact Comparison
The following graph compares the cumulative market impact (calculated by summating the marginal values from
the MCC re-run – the same as in section 2.2) for each month for the current year (indicated by type as a stacked
bar chart) against the cumulative values from the previous two years (the line graphs). The current year is further
categorised into system normal (NIL), outage, network support agreement (NSA) and negative residue constraint
equation types.
© AEMO July 2016
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MONTHLY CONSTRAINT REPORT
Figure 2-4 — Market Impact comparison
$50,000,000
$45,000,000
$40,000,000
Market Impact
$35,000,000
$30,000,000
$25,000,000
$20,000,000
$15,000,000
$10,000,000
$5,000,000
$0
NIL
Outage
NSA
Neg Res
2015 Total
2014 Total
2.9. Pre-dispatch RHS Accuracy
Pre-dispatch RHS accuracy is measured by the comparing the dispatch RHS value and the pre-dispatch RHS
value forecast four hours in the future. The following table shows the pre-dispatch accuracy of the top ten largest
differences for binding (in dispatch or pre-dispatch) constraint equations. This excludes FCAS constraint equations,
constraint equations that violated in Dispatch, differences larger than ±9500 (this is to exclude constraint equations
with swamping logic) and constraint equations that only bound for one or two Dispatch intervals. AEMO
investigates constraint equations that have a Dispatch/Pre-dispatch RHS difference greater than 5% and ten
absolute difference which have either bound for greater than 25 dispatch intervals or have a greater than $1,000
market impact. The investigations are detailed in 2.9.1.
Table 2-7 – Top 10 largest Dispatch / Pre-dispatch differences
Constraint Equation ID
Description
#DIs
% + Max
Diff
% + Avg
Diff
(System Normal Bold)
V::N_NIL_V4
Out = NIL, prevent transient instability for fault and trip of a
HWTS-SMTS 500 kV line, VIC accelerates, Basslink VIC
to TAS, Yallourn W Unit 1 on 500 kV.
67
570%
(161.63)
51.25%
(44.15)
V::N_NIL_V2
Out = NIL, prevent transient instability for fault and trip of a
HWTS-SMTS 500 kV line, VIC accelerates, Basslink TAS
to VIC, Yallourn W Unit 1 on 500 kV.
60
422%
(311.01)
38.61%
(84.39)
V>>SML_NIL_CONT_7B
Out = Nil, 66 kV line limited cyclic ratings not available,
avoid O/L Buangor to Arrarat 66kV line for loss of the
Arrarat to Horsham 220kV line
62
414%
(381.89)
71.02%
(79.9)
V>SMLBAHO4
Out = Ballarat to Horsham or Bendigo to Kerang line, avoid
O/L Buronga to Redcliffs (0X1) line for trip of Bendigo to
Kerang, or Ballarat to Horsham line
32
321%
(50.24)
117.99%
(22.43)
N^^V_NIL_1
Out = Nil, avoid voltage collapse in Southern NSW for loss
of the largest VIC generating unit or Basslink
18
107.07%
(193.31)
45.84%
(123.72)
Q>NIL_MUTE_757
Out= Nil, ECS for managing 757 H4 Mudgeeraba to T174
Terranora 110kV line, Summer and Winter ECS ratings
selected by SCADA status.
3
98.33%
(99.95)
98.33%
(99.95)
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© AEMO July 2016
MONTHLY CONSTRAINT REPORT
Constraint Equation ID
Description
#DIs
% + Max
Diff
% + Avg
Diff
(System Normal Bold)
Q>NIL_MUTE_758
Out= Nil, ECS for managing 758 H4 Mudgeeraba to T174
Terranora 110kV line, Summer and Winter ECS ratings
selected by SCADA status.
13
98.33%
(99.95)
98.33%
(99.95)
V::N_X_2SVC_V3
Out = 2 SVCs at Rowville or South East, prevent transient
instability for fault and trip of a HWTS-SMTS 500 kV line,
VIC accelerates, Basslink VIC to TAS, Yallourn W Unit 1
on 220 kV.
5
83.62%
(105.78)
40.05%
(64.38)
NSA_Q_BARCALDN
Network Support Agreement for Barcaldine GT to meet
local islanded demand for the planned outage of 7153 T71
Clermont to H15 Lilyvale or 7154 T72 Barcaldine to T71
Clermont 132kV line
82
65.54%
(13.1)
31.3%
(6.28)
S>>KHKN_SETB_SGKH
Out = Keith - Kincraig 132 kV line; avoid O/L of Snuggery Keith 132kV line on trip of either South East - Tailem Bend
275 kV line
165
53.07%
(139.63)
9.3%
(25.52)
2.9.1. Further Investigation
The following constraint equation(s) have been investigated:
V::N_NIL_V4: Investigated and no improvement can be made to the constraint equation at this stage.
V::N_NIL_V2: Investigated and no improvement can be made to the constraint equation at this stage
V>>SML_NIL_CONT_7B: Investigated and no improvement can be made to the constraint equation at this stage
V>SMLBAHO4: Investigated and mismatch was due to a difference between forecasted and actual values on each
single terminal station demand. No improvements can be made to the constraint equation at this stage.
N^^V_NIL_1: The Pre-dispatch for this constraint equation was recalculated in early May 2014 (with an updated to
the limit advice). No further improvements can be made at this time.
Q>NIL_MUTE_758: Investigated. Mismatch was due to difference between modelling of Terranora control scheme
and line status between DS and PD. No improvement can be made to the constraint equation at this stage.
NSA_Q_BARCALDN: Investigated and the PD formulation will be changed to improve its performance
S>>KHKN_SETB_SGKH: Investigated and no improvement can be made to the constraint equation at this stage.
© AEMO July 2016
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MONTHLY CONSTRAINT REPORT
3. GENERATOR / TRANSMISSION CHANGES
One of the main drivers for changes to constraint equations is from power system change, whether this is the
addition or removal of plant (either generation or transmission). The following table details changes that occurred in
June 2016.
Table 3-1 – Generator and transmission changes
Project
Date
Region
Notes
Hornsdale Wind Farm
2 June 2016
SA
New Generator
Mt Lock 275kV substation
15 June 2016
SA
New substation cut into Davenport to Canowie 275 kV line
Ararat Terminal Station
(ARTS)
29 June 2016
Vic
New substation cut into former Horsham to Waubra 220 kV
line.
3.1. Constraint Equation Changes
The following pie chart indicates the regional location of constraint equation changes. For details on individual
constraint equation changes refer to the Weekly Constraint Library Changes Report [2] or the constraint equations
in the MMS Data Model.[3]
Figure 3-1 — Constraint equation changes
Constraint Automation,
9, 1%
Vic, 91, 12%
NSW, 79, 10%
Non-Conformance, 2,
0%
Other, 1, 0%
Quick, 8, 1%
Tas, 281, 37%
SA, 293, 39%
The following graph compares the constraint equation changes for the current year versus the previous two years.
The current year is categorised by region.
__________________________________________________
2
AEMO. NEM Weekly Constraint Library Changes Report. Available at: http://www.aemo.com.au/Electricity/MarketOperations/Congestion-Information-Resource/NEM-Weekly-Constraint-Library-Changes-Report
3
AEMO. MMS Data Model. Available at: http://www.aemo.com.au/About-the-Industry/Information-Systems/Data-Interchange
Page 12 of 13
© AEMO July 2016
MONTHLY CONSTRAINT REPORT
Number of changes
Figure 3-2 — Constraint equation changes per month compared to previous two years
3400
3200
3000
2800
2600
2400
2200
2000
1800
1600
1400
1200
1000
800
600
400
200
0
Con Auto
© AEMO July 2016
SA
Qld
Tas
Vic
FCAS
NSW
2015 Total
2014 Total
Page 13 of 13