You can specify bus shunt conductances and capacitive susceptances in
the GS and BS columns of the bus matrix as MW and Mvars at nominal
voltage. And yes, the assumption that loads are modeled as PQ quantities
is standard in the load flow problem. Using a different model for loads
is a non-standard modification.
[email protected] wrote:
Hi SdT,
The load model for the standard power flow problem is based on bus
classification: load bus is regard as PQ bus or in other words, the load model
is constant power load. It's definitely true that no absolute real constant
power load with wild variation of voltage exists (also nearly true for constant
impedance load). However, for a real system, from the static point of view,
power restoring dynamic and voltage regulating will finally keep the voltage
near the rate value and the load power fitting the demand. So if you just want
to know the long term power flow at a normal operating point, bus
classification may not be a bad assumption. Of course, that assumption is not
proper for precise dynamic simulation or the research on voltage sensitive
phenomena. In all, whether a model is proper depends on your purpose.
In MATPOWER, you can model the constant inductance load as shunt compactor. Beyond that,
I think you have to change the code. The simplest improvement may be to add a column for
"shunt resistance" in bus data and slightly change the makeYbus function, then
you can have constant impedance load. Further, you need add new bus type and write code
for them from modeling to Jacobian matrix generation, or give up bus classification and
use some general form for solving nonlinear equations.
Shiyang Li
李诗旸
ECpE, Iowa State University
---- 原始邮件 -----
发件人：Sala de Tareas <[email protected]>
收件人：<[email protected]>
主题：Modelling passive / non controlled loads in matpower
日期：2012年10月23日 17点20分
hi there,
if yuo set up a load with 50kW in matpower it will always get those 50kW, no
matter how low the voltage has gone. this is an evidence, that matpower uses
controlled / active loads. the impedance of the load is regulated in a way,
that always the asked power is converted.
my question to you, since not all loads in reality are active, is if there is a
possibility in matpower to make analysises with passive / not controlled loads?
so less power when there is less voltage?
thank you in advance,SdT
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