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Template: AEMO Generator Performance Standards (GPS)

Preview of template's gridmo Flow showing Nodes

Last updated: 20 Mar 2024

Country:

AU

Software required:

PSS®E
PSCAD™

Source: AEMC | National Electricity Rules | Version 200 | 30 May 2023

Background​

The number and complexity of generation interconnections have increased during the energy transition. In an effort to ensure the adequate performance of generating systems and to ensure efficient design principles by utilising standards where possible, the AEMC established Technical Requirements in the National Electricity Rules. AEMO requires proponents to show compliance with these Technical Requirements (i.e. NER S5.2.5), as well as other requirements, and establish access standards - collectively referred to as "Generator Performance Standards (GPS)". This template includes a selection of tests to demonstrate compliance with these "Generator Performance Standards (GPS)".

Configuration​

To use this template:

  • Configure your Global Variables and Scenario Variables using gridmo's Model setup template.
  • Download this template using the download button above and load the template into the gridmo Web App.
  • Transfer your General tab data, Global Variables and Scenario Variables into this template using the 'Import' buttons in the gridmo Web App.
  • Follow the below GPS-requirement-specific setup steps.

S5.2.5.1 Reactive power capability​

The purpose of S5.2.5.1 is to identify your generating system's reactive power capability while operating across a range of different conditions (e.g. active power outputs, connection point voltages and ambient temperatures).

Constrained and unconstrained PQ capability curves are typically generated using DIgSILENT PowerFactory. Upon request, we included tests to construct a constrained PQ capability curve using PSS®E and/or PSCAD™. This constrained PQ capability curve is constructed where each point on the curve represents a dynamic simulation. In each dynamic simulation, the generating system is sent an active power and reactive power set point which purposefully exceeds the capability of the generating system and therefore settles upon the defined limits of the generating system.

note
  • Tests are conducted at infinite SCR and X/R.
  • Tests are conducted using a playback generator with infinite inertia.

S5.2.5.2 Quality of electricity generated​

The purpose of S5.2.5.2 is to confirm that your generating system's output does not exceed specified voltage fluctuation, harmonic voltage distortion and voltage unbalance limits.

info

We don't currently provide tests for S5.2.5.2.

S5.2.5.3 Generating system response to frequency disturbances​

The purpose of S5.2.5.3 is to confirm the ability of your generating system to maintain continuous uninterrupted operation for a particular frequency operating standard. We've also included tests to ensure that some form of frequency protection exists.

note
  • Tests are conducted at infinite SCR and X/R.
  • Tests are conducted using a playback generator with infinite inertia.
  • All frequency 'steps' are completed at a 4Hz/s ramp rate.

Step 1 - Choose frequency operating standard​

Choose a frequency ride-through SMIB playback test depending on your relevant frequency operating standard. Several common operating standards have been provided below. Copy and paste the chosen frequency operating standard into the PSS®E Dynamic and PSCAD™ Node SMIB frequency playback fields in all Nodes connected to Start Node 1028.

Under frequency​
0,          50
5,          50
5.75,       47
120,        47
120.5,      49
600,        49
600.2125,   49.85
Over frequency​
0,          50
5,          50
5.5,        52
120,        52
120.25,     51
600,        51
600.2125,   50.15

S5.2.5.4 Generating system response to voltage disturbances​

The purpose of S5.2.5.4 is to confirm the ability of your generating system to maintain continuous uninterrupted operation for particular voltages at the connection point. We've also included tests to ensure that some form of voltage protection exists.

note
  • Tests are conducted at infinite SCR and X/R.
  • Tests are conducted using a playback generator with infinite inertia.
  • Ride-through tests for each voltage range are chosen such that the time spent within that range includes any time spent in the more onerous ranges.
  • "over 130% of normal voltage" is represented by 132%.

S5.2.5.5 Generating system response to disturbances following contingency events​

The purpose of S5.2.5.5 is to confirm your generating system's response during and after disturbances. There are several parts of this performance standard:

  1. FRT transition bands | SMIB: Smoothly enter and exit a fault ride-through mode (known as transition band tests in this template).
  2. Voltage disturbance performance | SMIB: Response to balanced voltage disturbances (iq injection, iq rise time, iq settling time and P recovery time).
  3. Unbalanced faults | SMIB: Unbalanced fault performance (negative sequence capacitive current injection iq).
  4. Balanced MFRT | SMIB: Balanced multiple-fault ride-through performance (MFRT).
  5. Unbalanced MFRT | SMIB: Unbalanced multiple-fault ride-through performance (MFRT).
  6. Voltage disturbance performance | Network: Response to balanced voltage disturbances (iq injection, iq rise time, iq settling time and P recovery time).
  7. MFRT fault performance | Network: Balanced & unbalanced MFRT performance.
info

Tests for items 6 and 7, which help demonstrate compliance to S5.2.5.5(c), S5.2.5.5(d) and S5.2.5.5(k) coming soon!

The Analysis Nodes within this template assume Automatic Access Standards (AAS),however, we note that S5.2.5.5 is frequently a Negotiated Access Standard (NAS) based on the following potential criteria:

  • Achieving the AAS 4% (LVRT) and 6% (HVRT) reactive current gains may result in unstable operation (LVRT/HVRT flag retriggering) under low SCR conditions.
  • Achieving the AAS 40 ms and 70 ms iq rise and settling times may result in unstable performance (LVRT/HVRT flag retriggering) under very low SCR conditions.
  • Achieving the AAS 100 ms active power rise time after the completion of a fault may not be achievable for large generating systems under low SCR conditions.

Step 1 - Confirm LVRT and HVRT trigger in 1 - FRT transition bands Loop​

You may need to manually adjust the loop variables l_test_vdip and l_test_vrise within the 1 - FRT transition bands Loop to achieve the following test:

  • The voltage dips (l_test_vdip) low enough under the given SCR condition to trigger LVRT mode in your generating system - without tripping the generator
  • The voltage rises (l_test_vrise) high enough under the given SCR condition to trigger HVRT mode in your generating system - without tripping the generator

Step 2 - Consider what level of performance you are proposing​

The below analysis checklist assumes the following values which are frequently part of negotiated access standards. If you are proposing an access standard less than automatic, change the following values in the Analysis:

  • 4 (LVRT) and 6 (HVRT) reactive current gains as assessed in S5.2.5.5 - iq FRT injection curve.pdf
  • 40 ms and 70 ms iq rise and settling times as assessed in S5.2.5.5 - Voltage disturbance performance.csv
  • 0.05 p.u. for the difference between maximum and minimum LVRT and/or HVRT entrance voltages as the connection point as assessed in S5.2.5.5 - LVRT transition bands.pdf and/or S5.2.5.5 - HVRT transition bands.pdf

S5.2.5.6 Quality of electricity generated and continuous uninterrupted operation​

The purpose of S5.2.5.6 is to confirm that your generating system does not disconnect as a result of specified voltage fluctuation, harmonic voltage distortion and voltage unbalance levels.

info

We don't currently provide tests for S5.2.5.6. Additionally, compliance is often demonstrated via product information obtained via your OEM.

S5.2.5.7 Partial load rejection​

The purpose of S5.2.5.7 is to confirm the ability of your generating system to maintain continuous uninterrupted operation during and following a particular power system load reduction event or a separation event with an equivalent impact.

  • If your generating system is comprised of only grid-following asynchronous plant, then you could instead propose compliance with Section S5.2.5.7 via demonstrating compliance with Section S5.2.5.3 of the guidelines. Specifically, you could assert that any system separation event, regardless of load reduction of pre-disturbance level cannot exceed the minimum frequency band and ROCOF as per S5.2.5.3.
  • However - if you have a synchronous plant or grid-forming inverters in your generating system, the inertia of your generating system may need to be considered in your generating system's ability to maintain continuous uninterrupted operation during a partial load rejection event.

Step 1 - Configure network case(s)​

Configure the network case(s) used to complete the test. This includes Loop Variables such as l_network_case.

Step 2 - Create load reduction event​

Using one or more Commands in the relevant PSS®E Dynamic Node, create an appropriate power system load reduction event or a separation event in the network case.

S5.2.5.8 Protection of generating systems from power system disturbances​

The purpose of S5.2.5.8 is to confirm the generating system's active power response to power system frequency changes - in particular the speed at which the generating system output reduces due to an over frequency event.

Demonstration of performance is typically only required for generators > 30 MVA. Additionally, this test requires input from AEMO and/or your NSP to confirm at which frequency a reduction of power should be triggered.

note
  • Tests are conducted using a playback generator with infinite inertia.
  • All frequency 'steps' are completed at a 4Hz/s ramp rate.

Step 1 - Choose frequency operating standard​

Choose a frequency ride-through SMIB playback test depending on your relevant frequency operating standard. Several common operating standards have been provided below. Copy and paste the chosen frequency operating standard into the PSS®E Dynamic and PSCAD™ Node SMIB frequency playback fields in all Nodes connected to Start Node 1567.

0,          50
5,          50
5.25,       51
10,         51
10.25,      50

S5.2.5.9 Protection systems that impact on power system security​

The purpose of S5.2.5.9 is to confirm that your generating system has adequate protection systems.

info

We don't currently provide tests for S5.2.5.9. Additionally, compliance is often demonstrated via design reports.

S5.2.5.10 Protection to trip plant for unstable operation​

The purpose of S5.2.5.10 is to confirm that your generating system has adequate protection systems.

info

We don't currently provide tests for S5.2.5.10. Additionally, compliance is often demonstrated via design reports.

S5.2.5.11 Frequency control​

The purpose of S5.2.5.11 is to confirm the generating system's active power response to power system frequency changes. The response is tested:

  • to assess the value to which the active power is changed as part of a frequency response mode; and
  • to assess that it is adequately damped.
note
  • Only SMIB studies have been completed. Network-wide studies may be added to further demonstrate that the response is adequately damped.
  • Frequency 'steps' used to create the P(f) droop curve are completed at a 4Hz/s ramp rate.

Step 1 - P(f) droop curve | Choose frequency steps simulation time​

Choose the frequency steps simulation time in the "P(f) droop curve" tests which is sufficient for your generating system to settle. This simulation time will depend on your ramp up and ramp down control limits (e.g. expressed in MW/sec). If required, edit the simulation time of the relevant PSS®E Dynamic, PSCAD™ and Plot Nodes.

Step 2 - Choose active power control system ramp rate​

For the "Freq step during P ramp" tests, a frequency step occurs during an active power ramp. This test is to confirm the generating system's "output [is] the summation of the AGC setpoint and the PFR Settings" in accordance with section 2.3.1 of AEMO | Primary Frequency Response Requirements | Effective 8 May 2023. You may need to reduce the active power control system ramp rate to ≈ 0.02 [p.u./s] to ensure the frequency step occurs during the active power ramp.

Step 3 - Select source energy​

For the OF and UF tests, select source energy values which correspond to 50% and 5%. In the relevant Loop: Start Nodes, edit the following Loop Variables:

l_test_se_avail_pscad,1,1,1,1,X1,X1,Y1,Y1
l_test_se_avail_psse,1,1,1,1,X2,X2,Y2,Y2

where X and Y represent values to achieve source energy of 50% and 5%, respectively.

S5.2.5.12 Impact on network capability​

The purpose of S5.2.5.12 is to confirm the extent to which your generating system impacts inter-regional and intra-regional network capability.

The assessment is divided into two parts:

  • Static studies: Static studies may be used to assess thermal limits and voltage stability. Please refer to our template which addresses these requirements: Preliminary network studies.
  • Dynamic studies: Dynamic studies are completed where faults are applied on a network case where the generating system is explicitly modelled and modelled as a negative load. The responses from both representations of the generating system are compared.
info

We don't currently provide tests for S5.2.5.12, though this is coming soon.

S5.2.5.13 Voltage and reactive power control​

The purpose of S5.2.5.13 is to confirm the capability of your generating system's reactive power control system.

note
  • A 5% voltage disturbance test was chosen for the purposes of S5.2.5.13(c1)(3)(i).

Step 1 - Q(V) droop curve | Choose grid voltage steps simulation time​

Choose the grid voltage steps simulation time in the "Q(V) droop curve" tests which is sufficient for your generating system to settle. This simulation time will depend on your reactive power control system gains as well as your ramp up and ramp down control limits (e.g. expressed in MVAr/sec). If required, edit the simulation time of the relevant PSS®E Dynamic, PSCAD™ and Plot Nodes.

Step 2 - Choose PFref and Qref values​

Choose PFref and Qref values which correspond to a "...change in setpoint of... 50% of the reactive power capability" (e.g. 50% × 0.395 × rated active power for S5.2.5.1 AAS). Note that PFref values may be in different units depending on your OEM model (e.g. radians, degrees, unitless). If required, edit the PFref and Qref Commands in the relevant PSS®E Dynamic and PSCAD™ Nodes.

Step 3 - Choose size of shunt reactive element​

For network grid voltage steps, choose the size of a shunt reactive element to be inserted at the connection point to create ±5% steps.

info

Tests which include steps into limiters (i.e. S5.2.5.13(b)(4)(v)(B) and S5.2.5.13(c1)(3)(ii)) are not yet available in this template, but are coming soon.

S5.2.5.14 Active power control​

The purpose of S5.2.5.14 is to confirm the capability of your generating system's active power control system.

Step 1 - Choose spacing between active power steps​

Choose the spacing between active power steps which is sufficient for your generating system to reach each target set point. This spacing will depend on your ramp up and ramp down control limits (e.g. expressed in MW/sec). If required, edit the following Commands:

$s_psse_ds_p_command, AT=5, VAL=0.5
$s_psse_ds_p_command, AT=15, VAL=0.05
$s_psse_ds_p_command, AT=25, VAL=1

S5.2.5.15 Short circuit ratio​

The purpose of S5.2.5.15 is to confirm the ability of your generating system to to operate stably and remain connected at a specified low short circuit ratio.

S5.2.5.15 states that this requirement should be "...assessed in accordance with the methodology prescribed in the system strength impact assessment guidelines". Please refer to our template which addresses these guidelines: AEMO System Strength Impact Assessment Guidelines (Appendix B).

S5.2.5.16 Voltage phase angle shift​

The purpose of S5.2.5.16 is to confirm the ability of your generating system to avoid activating specific protection functions as a result of specific phase angle changes at the connection point.

As outlined in AEMO's draft determination submission, AEMO | Draft Determination – Efficient management of system strength | 17 June 2021, "it is inconsistent to document [specific protection systems] in the Generator Performance Standards." If this clause was consistent with S5.2, the purpose would most likely be extended to confirm the ability of your generating system to maintain continuous uninterrupted operation for specific phase angle changes at the connection point.

Step 1 - Choose voltage phase angle shift​

Choose a voltage phase angle shift depending on your relevant GPS requirements. Common requirements have been provided below. Copy and paste this text into the relevant PSS®E Dynamic and PSCAD™ Node SMIB angle playback fields.

0,          0
5,          20
15,         0
25,         -20
35,         0
45,         0

Assumptions​

  • Generally, Automatic Access Standard (AAS) is assumed for all tests and Analysis Nodes within the template.
  • Some GPS tests require a PSS®E model of the NEM (colloquially known as an 'OPDMS snapshot' in the industry). We do not provide these snapshots in this template. You will have to provide your own pre-tuned dynamic base cases for these tests.
  • Network frequency dependency is by default disabled, but can be disabled if desired.

Sources​

Revision history​

  • 15 April 2024 (v1.4.12):
    • Updated to align with newest template Sticky Note format.
    • Removed unused Internode Variables from Plot Node 1435 and Table Node 1443.
  • 20 March 2024 (v1.4.11)
    • Added S5.2.5.1 constrained PQ capability curve tests to this template.
    • Start Nodes renamed to indicate if they are SMIB or Network-wide studies.
    • Fixed typo in S5.2.5.7 test plot title, incorrectly referenced S5.2.5.14.
    • Fixed missing internode variable in Analysis Node 1752.
  • 30 January 2024 (v1.4.9)
    • Fixed S5.2.5.3 PSS®E Static Nodes used a different POC bus voltage target between the with-generator and without-generator tests.
    • Fixed Node 1368 referenced an incorrect test type.
  • 12 December 2023 (v1.4.7)
    • Added GRADIENT commands to S5.2.5.11 and S5.2.5.13 scatter plots to automatically calculate droop characteristics.
  • 14 November 2023 (v1.4.5)
    • Removed AEMO error bands from Plot Nodes when only one power system simulation software package is being plotted.
    • Added y-axis labels on single phase voltage plots.
    • Set DISPLAY=NO on several plots to minimise overcrowding of OUTPUT commands.
    • Removed the 3 second initialisation Analysis check on studies which do not have PSCAD™ studies.