how do I implement cut off generators and loads

[seedpower]

My goal is to keep transient stability:

In practical engineering, the generators generally are cut off as a whole.

Q1: At present, I have two ways to achieve this. One is to modify the u status of the generator, and the other is to set tm0=0 of the generator . Which one is better?

loads usually are cut off in acertain proportion.

Q2: Can I achieve this by setting Ppf * (1-proportion) of PQ load?

[cuihantao]

Q1: Set u to 0. One should not modify tm0.

Q2: That works. You can alternatively split the into into two when preparing the data.

[seedpower]

Thank you. The following is a generator cutting implementation.

import os
import andes
import copy
from andes.utils import get_case

ss = andes.run(andes.get_case("ieee14/ieee14_full.xlsx"), setup=False, default_config=True)
ss.add("Fault", dict(bus=8, tf=1.0, tc=2.0))
ss.setup()
ss.PFlow.run()

# tf=1.5s, cuf off GENROU5
ss.TDS.config.tf = 1.5
ss.TDS.config.criteria = 1
ss.TDS.run()

shed_gens = [5]
u_shed_idx = ss.GENROU.find_idx(keys='gen', values=shed_gens)
u = ss.GENROU.get(src='u', idx=u_shed_idx, attr='v')
u_new = u * 0
ss.GENROU.set(src='u', idx=u_shed_idx, attr='v', value=u_new)

# t=2.0s, restore u
ss.TDS.config.tf = 2.0
ss.TDS.run()
ss.GENROU.set(src='u', idx=u_shed_idx, attr='v', value=u)

# tf = 5s
ss.TDS.config.tf = 5
ss.TDS.config.criteria = 1
ss.TDS.run()
ss.TDS.load_plotter()
ss.TDS.plotter.plot(ss.GENROU.delta)

If the GENROU5 is not cut off, the transient instability occurs in t=1.99s.

Whether it is correct, perform the generator cutting operation from t=1.5s to t=2.0s, and the GENROU.delta is not equal to 0?

[cuihantao]

The generator was successfully disconnected because the rotor angle no longer changes. The power injection equation is u*(vd*Id+vq*Iq), which is zero after turning off. Reconnecting a generator poses a different question. The generator’s rotor angle upon reconnection will have an impact on the synchronization. Currently, the generator rotor angle remains at the pre fault value when disconnected. I don’t know how other tools handle this. If you know please post it here. Get Outlook for iOS<https://aka.ms/o0ukef>

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________________________________ From: seedpower ***@***.***> Sent: Tuesday, December 13, 2022 12:20:14 AM To: cuihantao/andes ***@***.***> Cc: Hantao Cui ***@***.***>; Comment ***@***.***> Subject: Re: [cuihantao/andes] how do I implement cut off generators and loads (Discussion #393) Thank you. The following is a generator cutting implementation. import os import andes import copy from andes.utils import get_case ss = andes.run(andes.get_case("ieee14/ieee14_full.xlsx"), setup=False, default_config=True) ss.add("Fault", dict(bus=8, tf=1.0, tc=2.0)) ss.setup() ss.PFlow.run() # tf=1.5s, cuf off GENROU5 ss.TDS.config.tf = 1.5 ss.TDS.config.criteria = 1 ss.TDS.run() shed_gens = [5] u_shed_idx = ss.GENROU.find_idx(keys='gen', values=shed_gens) u = ss.GENROU.get(src='u', idx=u_shed_idx, attr='v') u_new = u * 0 ss.GENROU.set(src='u', idx=u_shed_idx, attr='v', value=u_new) # t=2.0s, restore u ss.TDS.config.tf = 2.0 ss.TDS.run() ss.GENROU.set(src='u', idx=u_shed_idx, attr='v', value=u) # tf = 5s ss.TDS.config.tf = 5 ss.TDS.config.criteria = 1 ss.TDS.run() ss.TDS.load_plotter() ss.TDS.plotter.plot(ss.GENROU.delta) If the GENROU5 is not cut off, the transient instability occurs in t=1.99s. [图片]<https://user-images.githubusercontent.com/11022830/207239303-4d5da37d-83d7-41ac-a794-9c1889ec5901.png> Whether it is correct, perform the generator cutting operation from t=1.5s to t=2.0s, and the GENROU.delta is not equal to 0? [图片]<https://user-images.githubusercontent.com/11022830/207239208-e1af7f0c-26f6-4510-8003-12faf79618f8.png> ― Reply to this email directly, view it on GitHub<https://github.com/cuihantao/andes/discussions/393#discussioncomment-4386439>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ABSNZA64ZWKD4MOVPTN2GJLWNAIR5ANCNFSM6AAAAAAS3S3BVA>. You are receiving this because you commented.Message ID: ***@***.***>

[seedpower]

I don’t know. Can I use tm0=0 to simulate it?

import os
import andes
import copy
from andes.utils import get_case

ss = andes.run(andes.get_case("ieee14/ieee14_full.xlsx"), setup=False, default_config=True)
ss.add("Fault", dict(bus=8, tf=1.0, tc=2.0))
ss.setup()
ss.PFlow.run()

# tf=1.5s, cuf off GENROU5
ss.TDS.config.tf = 1.5
ss.TDS.config.criteria = 0
ss.TDS.run()

shed_gens = [5]
tm0_shed_idx = ss.GENROU.find_idx(keys='gen', values=shed_gens)
tm0 = ss.GENROU.get(src='tm0', idx=tm0_shed_idx, attr='v')
tm0_new = tm0 * 0
ss.GENROU.set(src='tm0', idx=tm0_shed_idx, attr='v', value=tm0_new)

# t=2.0s, restore tm0
ss.TDS.config.tf = 2.0
ss.TDS.run()
ss.GENROU.set(src='tm0', idx=tm0_shed_idx, attr='v', value=tm0)

# tf = 5s
ss.TDS.config.tf = 5
ss.TDS.config.criteria = 0
ss.TDS.run()
ss.TDS.load_plotter()
ss.TDS.plotter.plot(ss.GENROU.delta)

[cuihantao]

Please don't modify tm0 in any case. Setting tm0 to zero will not turn off the generator but provide a step up tm in the amount of tm0.

See a discussion here: https://psspy.org/psse-help-forum/question/2399/reconnecting-generators-during-dynamic-simulation/

[seedpower]

Q1: Is there a good way to implement a generator dynamic brake in ANDES?
Adaptive_Power_System_Emergency_Control_Using_Deep_Reinforcement_Learning_2.pdf
paper github: https://github.com/RLGC-Project/RLGC

Q2: If a generator cannot be dynamic brake in ANDES, how to implement cut off 50% of the a generator capacity dynamically?

[cuihantao]

Generator power adjustment is done through turbine governors, as in actual systems. You can alter the value of paux0 of the turbine governor to change the power setpoints. Refer to the specific governor model to calculate a paux0 that achieves a power reduction at your desired percentage.

[seedpower]

Thank you. I implemented a cut_off_generator_capacity() function to cut off desired percentage of generator capacity.
I called the function twice to cut off 40% of generator capacity. But I am not sure if it is right of the calculation of paux0. Is that right?

import andes

ss = andes.run(andes.get_case("ieee14/ieee14_full.xlsx"), setup=False, default_config=True)
ss.setup()
ss.PFlow.run()


def cut_off_generator_capacity(shed_gens, off_ratio):
    p_shed_idx = ss.TGOV1.find_idx(keys='syn', values=shed_gens)
    paux0 = ss.TGOV1.get(src='paux0', idx=p_shed_idx, attr='v')
    pref = ss.TGOV1.get(src='pref', idx=p_shed_idx, attr='v')

    # CHECK - calculate new paux0 according to off_ratio
    paux0_new = paux0 + pref * (-off_ratio)

    ss.TGOV1.set(src='paux0', idx=p_shed_idx, attr='v', value=paux0_new)

    print()
    print("pref\t=\t" + str(pref))
    print("paux0\t=\t" + str(paux0))
    print("paux0_new\t=\t" + str(paux0_new))
    print()

# tf = 1.0
ss.TDS.config.tf = 1.0
ss.TDS.run()
cuff_off_generator_capacity(["GENROU_1"], 0.2)
cuff_off_generator_capacity(["GENROU_1"], 0.2)

# tf = 10
ss.TDS.config.tf = 10
ss.TDS.config.criteria = 0
ss.TDS.run()
ss.TDS.load_plotter()
ss.TDS.plotter.plot(ss.GENROU.tm)

[cuihantao]

The calculation of paux0 does vary between different turbine governor models.

For TGOV1 (https://www.powerworld.com/WebHelp/Content/TransientModels_PDF/Generator/Governor/Governor%20TGOV1.pdf), paux0, which is equal to paux, modifies the pref signal that will be multiplied by 1/R. To get a 40% reduction in the output, your reduction has to be multiplied by R.

We have a TGOV1N model which moves the paux to be summed at the output of 1/R. See https://www.powerworld.com/WebHelp/Content/TransientModels_PDF/Generator/Governor/Governor%20TGOV1.pdf.

The way you check the tm looks correct to me.