Battery model for transient stability
Hi every one, I have used in PSSE, REGCA1, REECCU1 and REPC1 to simulate the dynamic model of a Battery energy storage for transient stability. Now I need to make this battery storage works only when I have a high deviation in the bus frequency but I don't know how to make this operation condition. Second I want to use that dynamic model to simulate a flywheel. so I need to adjust it to make it provide high active power in a short time for discharge. I don't know where to make this adjustment. Can any one help in that?
Is the frequency flag in the REPC1 model enabled?
Yes the Fflag = 1. I put the Pgen = 0 to avoid adding the battery to the load flow calculation, is this has any effect?
What is the value of SOCini, SOCmax and SOCmin in the REECCU1? The way I understood it, you are treating the BESS in standby/idle mode and let it discharge/charge during frequency event. Is that correct?
Yes exactly that's why I didn't add it to the load flow calculation. now SOCini = 1 because I want the battery to be fully charged at initial state, SOCmax = 1 and SOCmin = 0. I have also add T = 20sec.
I have this similar set-up before where battery is in idle and discharged power when i simulated a loss of generation (tripping of one combustion turbine) so I think this should work too for your set-up. What about the Ddn and Dup values? Also, a T=20 secs seems to be too small.
Ok for Ddn and Dup = 126. for the time I had the same doubt about the T but I didn't know how to calculate its optimum. I need the BESS to inject whatsoever needed active power in short time to sustain the system stability. how can I calculate T?
Use a value of T = 7200 seconds.
ok I'll tray this one. another question do I have to write anything in the RECPA1 VARs?
Typically, VAR is calculated during initialization, unless a user-specific input to the VAR of the model is required. in the REPCAU1 model, i let the VAR values be calculated when dynamic simulation is initialized.
@ffl Thanks a lot for your help. model is working now. I have another question, the disturbance I made is at 0.5 sec. however the BESS starts injects power at 1.5Sec. is their a time delay which I can adjust to let BESS work immediately. the Freq. dead band is 0.0008.
The BESS should start responding the moment the fault is cleared. Are the plots of P & Q, V, and F flat during the first 0.5 seconds? The flat response must be ensured so that the system is operating in steady-state and free from disturbances.
If the response of BESS looks like ramping for a couple of seconds, try to adjust the Iqrmax and Iqrmin in the REGCAU1 model.
@ffl The P response is flat till 1.5 Sec. Q and V are flat till 0.5 Sec then ramping. is their a time delay prevent injecting active power till specific time? somehow it looks like a time delay issue?
@ffl I found the problem, the frequency deviation was increasing at the first 1 Sec and thus the BESS needs to take power however the SOC inti = 1 and it can't take any power.
If the response is not flat, say for 15 seconds, you may need to fix this before proceeding to run other tests, e.g. faults.
Hi..i'm also in progress in modelling of a battery energy storage for transient stability. May I know what parameter data you use for Xsource?as i followed in some of input from this forum to use gen in load flow with Pgen 0, and Xsource=9999 or what parameter can i used? sorry for basic question.tq
Assuming you are using a generic battery energy storage, an Xsource of 9999 or any large value is suggested. When using a manufacturer-specific battery, you may want to look at the documentation because sometimes they include an Xsource value that corresponds to the battery model.
i see.. okay..i will try first and see how the result.. thanks ya...