Jacobian at nose point
Sir,
At nose point in P-V curve using cpf, nbsp;Jacobian matrix becomes singular.
i.e. determinant of Jacobian to be zero.I am getting very high negative value
of determinant nbsp;of jacobian at nose point. I have used following
code:nbsp;define_constants;nbsp;mpopt =
mpoption('out.all',0,'verbose',2,'out.bus',1);nbsp;mpopt =
mpoption(mpopt,'cpf.stop_at','nose','cpf.step',0.03);nbsp;mpopt =
mpoption(mpopt,'cpf.plot.bus',7,'cpf.plot.level',2);nbsp;mpcb =
loadcase('case39'); % load base casenbsp;mpct = mpcb; % set up target case
withnbsp;mpct.gen(:,[PG QG]) = mpcb.gen(:,[PG QG])*1.35nbsp;mpct.bus(:,[PD
QD]) = mpcb.bus(:,[PD QD])*1.35nbsp;results = runcpf(mpcb, mpct,
mpopt);nbsp;J=makeJac(results)
%%% determinant of Jnbsp;det(J)
ans =
nbsp;-1.0471e+126
Could
you please suggest me what necessary steps I should follow to get determinant
zero?
Thanking you.
Nilesh Patel
Re: PV curve using CPF
Sir,
At nose point in P-V curve using cpf, nbsp;Jacobian matrix becomes singular.
i.e. determinant of Jacobian to be zero. I am getting very high negative value
of determinant nbsp;of jacobian at nose point. My question is I doubt my
jacobian is not correct. How to get correct jacobian at nose point. I have
used following code:nbsp;
define_constants;nbsp;mpopt =
mpoption('out.all',0,'verbose',2,'out.bus',1);nbsp;mpopt =
mpoption(mpopt,'cpf.stop_at','nose','cpf.step',0.03);nbsp;mpopt =
mpoption(mpopt,'cpf.plot.bus',7,'cpf.plot.level',2);nbsp;mpcb =
loadcase('case39'); % load base casenbsp;mpct = mpcb; % set up target case
withnbsp;mpct.gen(:,[PG QG]) = mpcb.gen(:,[PG QG])*1.35nbsp;mpct.bus(:,[PD
QD]) = mpcb.bus(:,[PD QD])*1.35nbsp;results = runcpf(mpcb, mpct,
mpopt);nbsp;J=makeJac(results)
%%% determinant of Jnbsp;det(J)
ans =
nbsp;-1.0471e+126
Thank you.
From: Abhyankar, Shrirang G. lt;abhy...@anl.govgt;
Sent: Fri, 14 Aug 2015 02:28:21
To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt;
Subject: Re: PV curve using CPF
MATPOWER’s CPF, by default, uses a pseudo arclength parameterization that takes
a step in the tangent space of the PV curve. As such, the ‘MW' increments
depend on the steps taken along the tangent, and in turn on the slope of the
curve. If you want a
fixed ‘MW’ increase then you need to use natural parameterization instead.
(mpoption(‘cpf.parameterization’,’NATURAL’). Natural parameterization directly
uses the scaling parameter lambda and such has direct connection with MW
increments. However, note that
natural parameterization suffers from divergence near the fold point! I would
not use natural parameterization unless there is a really strong need.
Note that the step size for CPF, for natural parameterization, is given in
terms of increments of the scaling parameter lambda, where lambda = 0
represents the base case and lambda = 1 is the target case. Going from 100 MW
base case (lambda = 0) to 200
MW target case (lambda = 1) in 10 continuation steps would need a stepsize of
0.1. (mpoption(‘cpf.step’, 0.1).nbsp;
Shri
From: nilesh patel lt;nk2...@rediffmail.comgt;
Reply-To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt;
Date: Thursday, August 13, 2015 at 5:45 AM
To: matpowe...@list.cornell.edu lt;matpowe...@list.cornell.edugt;
Subject: Re: PV curve using CPF
It mean my system base case_P is 100 MW and reaches to 200 MW at nose point in
10 steps in cpf. so step size in this case is 10 MW. Is it correct?
Thanks.
From: Jose Luis Marin lt;mari...@gridquant.comgt;
Sent: Thu, 13 Aug 2015 14:05:07
To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt;
Subject: Re: PV curve using CPF
Lambda interpolates between the [P_base, Q_base]nbsp; andnbsp; [P_target,
Q_target] vectors of your choice, so therefore the relationship between the
lambda stepsize and the actual power increase on the buses depends on that.
--
Jose L. Marin
Gridquant España SL
Grupo AIA
On Wed, Aug 12, 2015 at 12:16 PM, nilesh patel
lt;nk2...@rediffmail.comgt; wrote:
Sir,
If i want to increase load in continuation power flow by step of 1 MW, What
should be the step size of Lamda. My system base case load is 5000 MW. As CPF
accuracy depends on step-size.
Thanks.
From: Jose Luis Marin lt;mari...@gridquant.comgt;
Sent: Mon, 10 Aug 2015 18:53:11
To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt;
Subject: Re: PV curve using CPF
Shruti is right, the value you obtain for lambda is valid for all the network,
since voltage collapse is a global phenomenon (in other words, you';;ll see a
nose point at the same value of lambda regardless of which bus you choose to
plot).nbsp; Remember that lambda
represents a fraction along the vector of injections linearly iterpolating
[P_base, Q_base]nbsp; tonbsp; [P_target, Q_target].nbsp; The value of Lambda
at the nose point is NOT the maximum loading point for that bus; rather, it is
the maximum loading value along the path
to the particular load/gen profile chosen as a target.
Of course, one may wonder about this other problem: for a given profile
[P_base, Q_base], what is the target direction [P_target, Q_target] for which
one would obtain the shortest value of critical lambda?nbsp; If this is what
you';;re thinking about, then it is
in general a hard problem.nbsp; I suggest these references by Ian Dobson, on
the concept of shortest distance to voltage collapse:
http://www.ece.wisc.edu/~dobson/PAPERS/publications.html#loading
--
Jose L. Marin
Gridquant España SL
Grupo AIA
On Mon, Aug 10, 2015 at 6:23 AM, nilesh patel
lt;nk2...@rediffmail.comgt; wrote:
Sir,
When we run continuation power flow for particular system, we get p-v curve for
selected bus. using this p-v curve, we can find Voltage stability Margin (in
MW) on that bus by difference of operating point to nose point lamda.
nbsp; nbsp
Re: PV curve using CPF
It mean my system base case_P is 100 MW and reaches to 200 MW at nose point in 10 steps in cpf. so step size in this case is 10 MW. Is it correct? Thanks. From: Jose Luis Marin lt;mari...@gridquant.comgt; Sent: Thu, 13 Aug 2015 14:05:07 To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Subject: Re: PV curve using CPF Lambda interpolates between the [P_base, Q_base]nbsp; andnbsp; [P_target, Q_target] vectors of your choice, so therefore the relationship between the lambda stepsize and the actual power increase on the buses depends on that. -- Jose L. Marin Gridquant España SL Grupo AIA On Wed, Aug 12, 2015 at 12:16 PM, nilesh patel lt;nk2...@rediffmail.comgt; wrote: Sir,If i want to increase load in continuation power flow by step of 1 MW, What should be the step size of Lamda. My system base case load is 5000 MW. As CPF accuracy depends on step-size. Thanks. From: Jose Luis Marin lt;mari...@gridquant.comgt; Sent: Mon, 10 Aug 2015 18:53:11 To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Subject: Re: PV curve using CPF Shruti is right, the value you obtain for lambda is valid for all the network, since voltage collapse is a global phenomenon (in other words, you';;ll see a nose point at the same value of lambda regardless of which bus you choose to plot).nbsp; Remember that lambda represents a fraction along the vector of injections linearly iterpolating [P_base, Q_base]nbsp; tonbsp; [P_target, Q_target].nbsp; The value of Lambda at the nose point is NOT the maximum loading point for that bus; rather, it is the maximum loading value along the path to the particular load/gen profile chosen as a target. Of course, one may wonder about this other problem: for a given profile [P_base, Q_base], what is the target direction [P_target, Q_target] for which one would obtain the shortest value of critical lambda?nbsp; If this is what you';;re thinking about, then it is in general a hard problem.nbsp; I suggest these references by Ian Dobson, on the concept of shortest distance to voltage collapse: http://www.ece.wisc.edu/~dobson/PAPERS/publications.html#loading -- Jose L. Marin Gridquant España SL Grupo AIA On Mon, Aug 10, 2015 at 6:23 AM, nilesh patel lt;nk2...@rediffmail.comgt; wrote: Sir,When we run continuation power flow for particular system, we get p-v curve for selected bus. using this p-v curve, we can find Voltage stability Margin (in MW) on that bus by difference of operating point to nose point lamda.nbsp; nbsp; nbsp; nbsp; nbsp; I agree lambda at nose point provides maximum loading value but that is for that bus only for which p-v curve is plotted.nbsp; My question is How to find Voltage Stability Margin for whole Network using P-V curve ? I mean how to find maximum lamda for whole network using nbsp;p-v curve? Thanks. From: Abhyankar, Shrirang G. lt;abhy...@anl.govgt; Sent: Fri, 07 Aug 2015 22:31:31 To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Subject: Re: PV curve using CPF I donⴠquite understand your question, can you please elaborate. The maximum value of loading scaling parameter ᬡmbda⠧ives a measure of how much power can be transferred for a given transfer direction. So, lambda is also a measure of the nose point for the whole network.nbsp; Shri From: nilesh patel lt;nk2...@rediffmail.comgt; Reply-To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Date: Friday, August 7, 2015 at 8:46 AM To: matpower-l lt;matpowe...@list.cornell.edugt;, MATPOWER-L lt;MATPOWER-L@cornell.edugt; Subject: PV curve using CPF Dear Sir, P-V curve solution using continuation power flow gives nose point (maximum loading point) for individual bus. My question is - How to get nose point for whole network (all buses) using PV curve ?nbsp; I want to find network voltage stability margin rather than individual bus margin using CPF. Thanks. Nilesh Patel Get your own FREE website, FREE domain amp; FREE mobile app with Company email. nbsp;Know More gt;
Re: PV curve using CPF
Sir,If i want to increase load in continuation power flow by step of 1 MW, What should be the step size of Lamda. My system base case load is 5000 MW. As CPF accuracy depends on step-size. Thanks. From: Jose Luis Marin lt;mari...@gridquant.comgt; Sent: Mon, 10 Aug 2015 18:53:11 To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Subject: Re: PV curve using CPF Shruti is right, the value you obtain for lambda is valid for all the network, since voltage collapse is a global phenomenon (in other words, you';ll see a nose point at the same value of lambda regardless of which bus you choose to plot).nbsp; Remember that lambda represents a fraction along the vector of injections linearly iterpolating [P_base, Q_base]nbsp; tonbsp; [P_target, Q_target].nbsp; The value of Lambda at the nose point is NOT the maximum loading point for that bus; rather, it is the maximum loading value along the path to the particular load/gen profile chosen as a target. Of course, one may wonder about this other problem: for a given profile [P_base, Q_base], what is the target direction [P_target, Q_target] for which one would obtain the shortest value of critical lambda?nbsp; If this is what you';re thinking about, then it is in general a hard problem.nbsp; I suggest these references by Ian Dobson, on the concept of shortest distance to voltage collapse: http://www.ece.wisc.edu/~dobson/PAPERS/publications.html#loading -- Jose L. Marin Gridquant España SL Grupo AIA On Mon, Aug 10, 2015 at 6:23 AM, nilesh patel lt;nk2...@rediffmail.comgt; wrote: Sir,When we run continuation power flow for particular system, we get p-v curve for selected bus. using this p-v curve, we can find Voltage stability Margin (in MW) on that bus by difference of operating point to nose point lamda.nbsp; nbsp; nbsp; nbsp; nbsp; I agree lambda at nose point provides maximum loading value but that is for that bus only for which p-v curve is plotted.nbsp; My question is How to find Voltage Stability Margin for whole Network using P-V curve ? I mean how to find maximum lamda for whole network using nbsp;p-v curve? Thanks. From: Abhyankar, Shrirang G. lt;abhy...@anl.govgt; Sent: Fri, 07 Aug 2015 22:31:31 To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Subject: Re: PV curve using CPF I donⴠquite understand your question, can you please elaborate. The maximum value of loading scaling parameter ᬡmbda⠧ives a measure of how much power can be transferred for a given transfer direction. So, lambda is also a measure of the nose point for the whole network.nbsp; Shri From: nilesh patel lt;nk2...@rediffmail.comgt; Reply-To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Date: Friday, August 7, 2015 at 8:46 AM To: matpower-l lt;matpowe...@list.cornell.edugt;, MATPOWER-L lt;MATPOWER-L@cornell.edugt; Subject: PV curve using CPF Dear Sir, P-V curve solution using continuation power flow gives nose point (maximum loading point) for individual bus. My question is - How to get nose point for whole network (all buses) using PV curve ?nbsp; I want to find network voltage stability margin rather than individual bus margin using CPF. Thanks. Nilesh Patel Get your own FREE website, FREE domain amp; FREE mobile app with Company email. nbsp;Know More gt;
Re: PV curve using CPF
Sir,When we run continuation power flow for particular system, we get p-v curve for selected bus. using this p-v curve, we can find Voltage stability Margin (in MW) on that bus by difference of operating point to nose point lamda.nbsp; nbsp; nbsp; nbsp; nbsp; I agree lambda at nose point provides maximum loading value but that is for that bus only for which p-v curve is plotted.nbsp; My question is How to find Voltage Stability Margin for whole Network using P-V curve ? I mean how to find maximum lamda for whole network using nbsp;p-v curve? Thanks. From: Abhyankar, Shrirang G. lt;abhy...@anl.govgt; Sent: Fri, 07 Aug 2015 22:31:31 To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Subject: Re: PV curve using CPF I donⴠquite understand your question, can you please elaborate. The maximum value of loading scaling parameter ᬡmbda⠧ives a measure of how much power can be transferred for a given transfer direction. So, lambda is also a measure of the nose point for the whole network.nbsp; Shri From: nilesh patel lt;nk2...@rediffmail.comgt; Reply-To: MATPOWER discussion forum lt;matpowe...@list.cornell.edugt; Date: Friday, August 7, 2015 at 8:46 AM To: matpower-l lt;matpowe...@list.cornell.edugt;, MATPOWER-L lt;MATPOWER-L@cornell.edugt; Subject: PV curve using CPF Dear Sir, P-V curve solution using continuation power flow gives nose point (maximum loading point) for individual bus. My question is - How to get nose point for whole network (all buses) using PV curve ? nbsp;I want to find network voltage stability margin rather than individual bus margin using CPF. Thanks. Nilesh Patel
PV curve using CPF
Dear Sir,P-V curve solution using continuation power flow gives nose point (maximum loading point) for individual bus. My question is - How to get nose point for whole network (all buses) using PV curve ? nbsp;I want to find network voltage stability margin rather than individual bus margin using CPF. Thanks. Nilesh Patel
error during powerflow run
Dear Sir,nbsp; I am getting following error while i m running power flow of 450 bus system. What could be the problem? Warning: Matrix is singular to working precision.nbsp;gt; In newtonpf at 108nbsp; In runpf at 224nbsp;Warning: Matrix is singular to working precision.nbsp;Newton's method power flow did not converge in 10 iterations. Thanks. Nilesh Patel
Merging of lines..
Dear Sir,nbsp; nbsp; nbsp;nbsp;My power system to be simulated consist of three parallel lines having same length and all nbsp;parameters between two buses. (There are no. of such lines in parallel so system size increases to much). My question is- Can i merge all parallel (three) lines as one line in simulation or all actual lines to be taken? Thanking u.nbsp; nbsp; Nilesh Patel
Dispatchable load
Hello sir,i have to use fixed load as dispatchable load to reschedule demand for overload alleviation. My question is that after running acopf, i am getting in result each nbsp;dispatchable load converted to fixed nbsp;generation block of 15 MW only. Can this block of 15 MW changed to different value? Thanks. Nilesh Patel
querry in add constraints in extended opf
Dear Sir,nbsp; i m using extended opf where in i hv modified toggle reserves
as per my function..i m getting error during adding constraints as below:
om = add_constraints(om, 'R1',Ar, deltaPupmax/mpc.baseMVA,
deltaPupmax/mpc.baseMVA,{'R1','R2'});om = add_constraints(om, 'R2',Ar,
deltaPdownmax/mpc.baseMVA,deltaPdownmax/mpc.baseMVA,{'R1','R2'});
R1,R2 nbsp;are variables i have taken.
Error i am getting is:MATPOWER Version 5.0b1, 01-Jul-2014 -- AC Optimal Power
FlowMATLAB Interior Point Solver -- MIPS, Version 1.0.2, 01-Jul-2014Numerically
Failed
Did not converge in 3 iterations.
gt;gt;gt;gt;gt; nbsp;Did NOT converge (0.10 seconds)
nbsp;lt;lt;lt;lt;lt;
Where could be the problem?? Do needful in the matter.
Thanks.
Nilesh Patel
Dispatchable load
Dear sir,I m working on congestion cost minimization. My objective function is to minimise rescheduling demand (load) cost. The objective function nbsp;is attached herewith for your reference. My questions are:1. Shall i use dispatchable load for rescheduling demand (del Pd (up/down) in obj. function.)2. Which changes should be made in Generator Cost Data format for the same. Thanks. Nilesh Patel S.P.C.E. Visnagar, India 9979249556
