Modeling and Model Validation of BESS

Transcription

1 Modeling and Model Validation of BESS P. Pourbeik WECC MVWG Meeting January 24-26, 2018

2 Acknowledgement Slides 7 to 12 in this presentation are based on work published in: [1] P. Pourbeik and J. K. Petter, Modeling and validation of battery energy storage systems using simple generic models for power system stability studies, CIGRE Science and Engineering, October 2017, pp (available for free download at: Grateful acknowledge Jeffery Petter, Northern Power Systems.

3 MOD 26 / 27 We are all well familiar with the NERC MODs for model validation of generation equipment They apply equally for renewable energy systems, as well as synchronous generation In previous presentations we have looked at Wind and PV validation examples

4 MOD 26 / 27 The question has been raised by many in WECC MVWG as to: Do these standards apply to battery energy storage systems (BESS)? If so, how would testing BESS differ from the other types of resources?

5 Do the Standards Apply to BESS? Conceptually yes, since BESS can be a resource and it can have both volt/var control (MOD ) and primary frequency response (MOD ) Practically most BESS being deployed today is on the distribution network and not directly connected to the bulk electric system (BES), so it probably does not meet criteria (i.e. not directly connected to BES, and below 75 MVA)

6 Are 2 nd Generation Models Reasonable? Are there any examples to give some sort of confidence that the models are reasonable? Yes here is an example of model verification against detailed 3-phase design models see details presented in reference [1]

7 Example generic vs EMT model See reference [1] for details Generic 2 nd generation RES in GE PSLF BESS Step-Up Transformer P gen P ref_gen REPC_A Vt Pref Q ref_g P ref_g REEC_C I qcmd Pe REGC_A I pcmd } Qe

8 Example generic vs EMT model Detailed (proprietary) EMT model in MATLAB by Northern Power Systems PLL V Ø F Reference frame manipulations I αβ * V I Current Regulator I V Ip* Iq* Ip Iq V PWMs Inverter Control DC AC

9 Example generic vs EMT model 3-phase fault (one example many run, both charging and discharging)

10 Example generic vs EMT model Voltage reference step test

11 Example generic vs EMT model Frequency reference step test

12 Example generic vs EMT model Unbalance (SLG) fault

13 Model Validation MOD What if a BESS is truly large enough and connected at BES, thus requiring NERC MOD verification? This would be no different to model validation of a type3/4 WTG or PV, that is, either use: Disturbance monitoring, or Staged testing: Voltage reference step tests Frequency reference step tests MOD 25 to the extent possible in the field (i.e. keep first and foremost in mind safety and grid reliability, e.g. like any other resource may not be able to push to limits as grid voltage may exceed safety limits)

14 Summary Most BESS is below the threshold and connected to the distribution network so direct validation/testing is not required Vendors should be able to tune 2 nd generation models to get reasonable dynamic performance for large scale stability studies If ever one has a large enough BESS to required actual MOD validation, approach would be no different to other inverter based resources (e.g. type 3/4 wind or PV)