: Public Class
Created: 03/05/2009 08:14:39
Modified: 23/08/2012 10:50:55
Project:
Advanced:
Aggregate induction motor load. This model  is used to represent a fraction of an ordinary load as "induction motor load".  It allows load that is treated as ordinary constant power in power flow analysis to be represented by an induction motor in dynamic simulation.  If <b>Lpp</b> = 0. or <b>Lpp</b> = <b>Lp</b>, or <b>Tppo</b> = 0.,  only one cage is represented. Magnetic saturation is not modelled. Either a "one-cage" or "two-cage" model of the induction machine can be modelled. Magnetic saturation is not modelled.<br/><br/>This model is intended for representation of aggregations of many motors dispersed through a load represented at a high voltage bus but where there is no information on the characteristics of individual motors.<br/><br/>This model treats a fraction of the constant power part of a load as a motor. During initialisation, the initial power drawn by the motor is set equal to <b>Pfrac</b> times the constant <b>P</b> part of the static load.  The remainder of the load is left as static load.<br/><br/>The reactive power demand of the motor is calculated during initialisation as a function of voltage at the load bus. This reactive power demand may be less than or greater than the constant <b>Q</b> component of the load.  If the motor's reactive demand is greater than the constant <b>Q</b> component of the load, the model inserts a shunt capacitor at the terminal of the motor to bring its reactive demand down to equal the constant <b>Q</b> reactive load.  <br/>If a motor model and a static load model are both present for a load, the motor <b>Pfrac</b> is assumed to be subtracted from the power flow constant <b>P</b> load before the static load model is applied.  The remainder of the load, if any, is then represented by the static load model.<br/>
Attribute
Public Float
  d
Details:
Notes: Damping factor (D).  Unit = delta P/delta speed.  Typical Value = 2.<br/>
Public Seconds
  h
Details:
Notes: Inertia constant (H) (not=0).  Typical Value = 0.4.<br/>
Public Float
  lfac
Details:
Notes: Loading factor – ratio of initial P to motor MVA base (Lfac).  Typical Value = 0.8.<br/>
Public PU
  lp
Details:
Notes: Transient reactance (Lp).  Typical Value = 0.15.<br/>
Public PU
  lpp
Details:
Notes: Subtransient reactance (Lpp).  Typical Value = 0.15.<br/>
Public PU
  ls
Details:
Notes: Synchronous reactance (Ls).  Typical Value = 3.2.<br/>
Public Float
  pfrac
Details:
Notes: Fraction of constant-power load to be represented by this motor model (Pfrac) (#gt;=0.0 and #lt;=1.0).  Typical Value = 0.3.<br/>
Public PU
  ra
Details:
Notes: Stator resistance (Ra).  Typical Value = 0.<br/>
Public Seconds
  tbkr
Details:
Notes: Circuit breaker operating time (Tbkr).  Typical Value = 0.08.<br/>
Public Seconds
  tpo
Details:
Notes: Transient rotor time constant (Tpo) (not=0).  Typical Value = 1.<br/>
Public Seconds
  tppo
Details:
Notes: Subtransient rotor time constant (Tppo).  Typical Value = 0.02.<br/>
Public Seconds
  tv
Details:
Notes: Voltage trip pickup time (Tv).  Typical Value = 0.1.<br/>
Public PU
  vt
Details:
Notes: Voltage threshold for tripping (Vt).  Typical Value = 0.7.<br/>
Element Source Role Target Role
LoadAggregate
Class  
Name: LoadMotor
Aggregate motor (dynamic) load associated with this aggregate load.
Name: LoadAggregate
Aggregate load to which this aggregate motor (dynamic) load belongs.
Details:
 
Object Type Connection Direction Notes
IdentifiedObject Class Generalization To