Constant impedance load

This section describes the constant impedance load component from microgrid library.

The constant impedance load component is located in Microgrid Library. Component icon and properties window are shown in Table 1. The constant impedance load component represents a three-phase balanced or unbalanced constant impedance load. The possible combinations for the impedance are R, RL series connection and RC series connection.

Table 1. Constant impedance load in the Schematic Editor core library
component component dialog window component parameters
  • Property tabs:
    • 1 - General
    • 2 - Three-phase
    • 3 - Phase A
    • 4 - Phase B
    • 5 - Phase C
Figure 1. Constant impedance load component view under its mask.

Tab: "General"

In this tab properties that are aplicable to both balanced an unbalanced operation can be set.

Figure 2. General properties window tab
Parameter Code name Description
Nominal frequency fn Nominal grid frequency.
Connection type conn_type Combo box that defines the three-phase connection. Options are Y (wye or star) or Δ (delta or triangle) connections.
Enable neutral connection enable_neutral By checking this box, an additional port that represents the neutral of a star connection will be added.
Set balanced 3ph power set_balanced By checking this field, the power will be balanced. If unchecked, the power can be defined per phase independently.

Tab: "Three-phase"

In this properties tab, power ratings of the load can be defined for balanced load option.

Figure 3. Three-phase properties window tab
Parameter Code name Description
Nominal 3ph line voltage Vn_3ph Nominal grid line to line voltage.
Nominal 3ph power Sn_3ph Desired three phase apparent power to be consumed.
Power factor mode 3ph pf_mode_3ph This field allows chosing among lag, lead or unit power factors (inductive, capacitive or pure resistive load).
Power factor 3ph pf_3ph Power factor value applied on chosen power factor mode (when power factor mode is not set to unit).

Tabs: "Phase A", "Phase B", "Phase C" for Y connection

These tabs are used when Set balanced 3ph power is not checked in the General tab. In these tabs user can enter the voltage, power and power factor per phase. The parameters described here are for Y connection.

Figure 4. Phase A propeties window tab
Parameter Code name Description
Nominal phase voltage (VAn, VBn or VCn) VAn, VBn or VCn Nominal line to neutral voltage of the respective phase.
Nominal phase power (SAn, SBn or SCn) SAn, SBn or SCn Desired line to neutral apparent power consumed for the respective phase.
Power factor mode pf_modeA, pf_modeB or pf_modeC This field allows chosing among lag, lead or unit power factors (inductive, capacitive or pure resistive load) for the respective phase.
Power factor (A, B or C) pfA, pfB or pfC Power factor of the respective phase (when power factor mode is not set to unit).

Tabs: "Phase A", "Phase B", "Phase C" for Δ connection

These tabs are used when Set balanced 3ph power is not checked in the General tab. In these tabs user can enter the voltage, power and power factor per phase. The parameters described here are for Δ connection.

Figure 5. Phase A propeties window tab
Parameter Code name Description
Nominal line voltage (VAB, VBC or VCA) VAB, VBC or VCA Nominal line to line voltage between the respective phases.
Nominal line power (SAB, SBC or SCA) SAB, SBC or SCA Desired line to line apparent power consumed between the respective phases.
Power factor mode pf_modeA, pf_modeB or pf_modeC This field allows chosing among lag, lead or unit power factors (inductive, capacitive or pure resistive load) for the respective phase.
Power factor (A, B or C) pfA, pfB or pfC Power factor of the respective phase (when power factor mode is not set to unit).

Example

Overall behavior can be better understood with the use of the given constant impedance load example:

Model name: meter_and_const_z_load.tse

SCADA interface: SCADA_Panel.cus

Path: /examples/models/microgrid/meter_and_constant_z_load/