c i f i c a DIgSILENT Pacific P Power system engineering and - PowerPoint PPT Presentation

c i f i c a DIgSILENT Pacific P Power system engineering and software T N Validation of solar power plant dynamic model E using commissioning test measurements L Desmond Chong Technical Seminar PowerFactory 2020 I 14 February 2020 S g I D

c i f i c a P DIgSILENT Pacific’s NEM experience during 2017-19: T Over 20 solar farms • N Located in VIC, NSW and QLD • E Designed 1,900 MW • Commissioned 920 MW • L I S g I 2 D

c i f i c a P Agenda • NEM commissioning journey T • Model validation tests N • Model overlay examples E • Challenges during model validation process L I • Reflections on model validation methodology S • Conclusions g I 3 D

c i f i c a Commissioning journey in NEM P 3 months after 3 months before T • Compliance • Model assessment assessment results N • Technical study • Model validation • Commissioning using test program measurements E L I Require model S During overlay with commissioning measurement g • Load profile • Pre-test simulation I • Hold point tests 4 D

c i f i c a Hold point testing P T Compliant Next hold point / Tests at Hold point report Yes Meet model Yes with technical unrestricted pre-defined (20 – 400+ accuracy performance commercial MW level pages) requirements? N standard? operation No E No Yes L Pose system Repeat technical Approved Yes No Provide technical studies with new security by AEMO justification threat? and NSP? model/settings I S No Good justification g can avoid repeat of I tests 5 D

c i f i c a Solar power plant dynamic model validation P • Inverter and power plant controller (PPC) dynamic models to be validated T • Equivalent lumped collector network model is mainly used in the model validation PPC V, I N • Model validation test type: o Reactive power (or power factor) step test E o Voltage step test o Active power ramping test o Frequency control test P command L Q command o External voltage disturbance test (e.g. capacitor switching test) o Reactive power capability assessment I S • Fault-ride-through performance is difficult to be validated on site g I 6 D

c i f i c a Measurement for commissioning tests P Meter requirements: T Time synchronised with other • meters HV and MV N terminals of main High speed monitoring (sampling • transformer rate >10kHz) E Calibrated • Independent of the control • L system Inverter LV I terminal electrically S CLOSEST to MV collector Inverter LV bus terminal g electrically FURTHEST to MV collector bus I 7 D

c i f i c a Model overlay example 1 - Voltage step tests P T N E L I S g I 8 D

c i f i c a Model overlay example 2 – Active power ramp tests P T N E L I S g I 9 D

c i f i c a Model overlay example 3 – Capacitor switching tests P T N E L I S g I 10 D

c i f i c a Challenge 1 – Reduced number of inverters P T Original MVA base Original PPC gain N Reduced MVA base Original PPC gain E Measurement Reduced MVA base Reduced PPC gain L I S g I 11 D

c i f i c a Challenge 2 – Low sampling rate of PPC meter P PPC cycle time ≈ 100ms • Default sampling rate of PPC meter • T = 200ms (or 1s) N Model alignment becomes an issue • when sampling rate ≥ 200ms Nyquist sampling theorem, i.e. • E <50ms sampling rate L I S g I 12 D

c i f i c a Challenge 3 – Different frequency step application P T On site setup N E L I Model simulation setup S g I 13 D

c i f i c a Challenge 4 – Variation in solar irradiance P T N E L I S g I 14 D

c i f i c a Reflections on model validation methodology P • Existing generating system model validation requirements used in NEM are mainly developed based on T synchronous machine commissioning test experience N • Differences between synchronous machine and inverter technologies: Synchronous machine Inverter E Each generating system is unique Inverter system design is standardised and modular L PID control can be measured on-site I Inverter control algorithms are “blackbox” S Generating system responses are relatively slower Generating system responses can be very fast g I 15 D

c i f i c a Reflections on model validation methodology P In light of differences between synchronous machine and inverter technologies, reconsideration of the T model validation objectives and methodology is needed: N 1. For the same inverter type, is it better to perform type testing at the OEM factory with site-specific settings downloaded to the inverters? E 2. Can conventional RMS model accurately represent sophisticated power electronic inverter and controls? L 3. Is it still reasonable to expect plant measurement to align very closely with simulated response? I 4. How will the commissioning tests and model validation process be affected by supporting plants within the S solar power plants (e.g. synchronous condenser, battery storage)? g I 16 D

c i f i c a Conclusions P • Solar power plant commissioning is relatively a new experience in NEM (and probably elsewhere in the world) T - Different grid operators have different requirements and methodologies - More and more requirements in time N - Cause delay in commissioning timeframe and increase in cost • Model validation process is valuable as it enables better understanding of the solar power plant performance E and capability - This is the main reason for sharing this commissioning experience L • In order to streamline the model validation process, it is good practice to ensure that: - Model parameters are consistent to the actual plant configuration I - Detailed test log is kept S - Measurement equipment is calibrated g I 17 D

c i f i c a P T N E L I S DIgSILENT Pacific g Power system engineering and software I D