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 来自新浪邮箱手机网页版
