Load

Note

Loads should always have a positive p_mw value, since all power values are given in the consumer system. If you want to model constant generation, use a Static Generator (sgen element) instead of a negative load.

Create Function

pandapower.create_load(net, bus, p_mw, q_mvar=0, const_z_percent=0, const_i_percent=0, sn_mva=nan, name=None, scaling=1.0, index=None, in_service=True, type='wye', max_p_mw=nan, min_p_mw=nan, max_q_mvar=nan, min_q_mvar=nan, controllable=nan)

Adds one load in table net[“load”].

All loads are modelled in the consumer system, meaning load is positive and generation is negative active power. Please pay attention to the correct signing of the reactive power as well.

INPUT:

net - The net within this load should be created

bus (int) - The bus id to which the load is connected

OPTIONAL:

p_mw (float, default 0) - The real power of the load

  • postive value -> load

  • negative value -> generation

q_mvar (float, default 0) - The reactive power of the load

const_z_percent (float, default 0) - percentage of p_mw and q_mvar that will be associated to constant impedance load at rated voltage

const_i_percent (float, default 0) - percentage of p_mw and q_mvar that will be associated to constant current load at rated voltage

sn_mva (float, default None) - Nominal power of the load

name (string, default None) - The name for this load

scaling (float, default 1.) - An OPTIONAL scaling factor to be set customly

type (string, ‘wye’) - type variable to classify the load: wye/delta

index (int, None) - Force a specified ID if it is available. If None, the index one higher than the highest already existing index is selected.

in_service (boolean) - True for in_service or False for out of service

max_p_mw (float, default NaN) - Maximum active power load - necessary for controllable loads in for OPF

min_p_mw (float, default NaN) - Minimum active power load - necessary for controllable loads in for OPF

max_q_mvar (float, default NaN) - Maximum reactive power load - necessary for controllable loads in for OPF

min_q_mvar (float, default NaN) - Minimum reactive power load - necessary for controllable loads in OPF

controllable (boolean, default NaN) - States, whether a load is controllable or not. Only respected for OPF

OUTPUT:

index (int) - The unique ID of the created element

EXAMPLE:

create_load(net, bus=0, p_mw=10., q_mvar=2.)

pandapower.create_load_from_cosphi(net, bus, sn_mva, cos_phi, mode, **kwargs)

Creates a load element from rated power and power factor cos(phi).

INPUT:

net - The net within this static generator should be created

bus (int) - The bus id to which the load is connected

sn_mva (float) - rated power of the load

cos_phi (float) - power factor cos_phi

mode (str) - “ind” for inductive or “cap” for capacitive behaviour

**kwargs are passed on to the create_load function

OUTPUT:

index (int) - The unique ID of the created load

All elements are modeled from a consumer point of view. Active power will therefore always be positive, reactive power will be negative for inductive behaviour and positive for capacitive behaviour.

Input Parameters

net.load

Parameter

Datatype

Value Range

Explanation

name

string

name of the load

bus *

integer

index of connected bus

p_mw*

float

\(\geq 0\)

active power of the load [MW]

q_mvar*

float

reactive power of the load [MVar]

const_z_percent*

float

\([0,100]\)

percentage of p_mw and q_mvar that is associated to constant impedance load at rated voltage [\(\%\)]

const_i_percent*

float

\([0,100]\)

percentage of p_mw and q_mvar that is associated to constant current load at rated voltage [\(\%\)]

sn_mva

float

\(>0\)

rated power of the load [kVA]

scaling *

float

\(\geq 0\)

scaling factor for active and reactive power

in_service*

boolean

True / False

specifies if the load is in service.

type*

String

wye/delta

Connection Type of 3 Phase Load(Valid for three phase load flow only)

controllable**

bool

States if load is controllable or not, load will not be used as a flexibilty if it is not controllable

max_p_mw**

float

Maximum active power

min_p_mw**

float

Minimum active power

max_q_mvar**

float

Maximum reactive power

min_q_mvar**

float

Minimum reactive power

*necessary for executing a power flow calculation.

Note

The apparent power value sn_mva is provided as additional information for usage in controller or other applications based on panadapower. It is not considered in the power flow!

Electric Model

Loads are modelled as PQ-buses in the power flow calculation, with an option to use the so-called ZIP load model, where a load is represented as a composition of constant power (P), constant current (I) and constant impedance (Z):

alternate Text

What part of the load is considered constant with constant power, constant current or constant impedance is defined as follows:

\begin{align*} z_{const} =& const\_z\_percent / 100 \\ i_{const} =& const\_i\_percent / 100 \\ p_{const} =& (100 - const\_z\_percent - const\_i\_percent) / 100 \end{align*}

The load power values are then defines as:

\begin{align*} P_{load} =& p\_mw \cdot scaling \cdot (p_{const} + z_{const} \cdot V^2 + i_{const} \cdot V ) \\ Q_{load} =& q\_mvar \cdot scaling \cdot (p_{const} + z_{const} \cdot V^2 + i_{const} \cdot V) \end{align*}

Result Parameters

net.res_load

Parameter

Datatype

Explanation

p_mw

float

resulting active power demand after scaling and after considering voltage dependence [MW]

q_mvar

float

resulting reactive power demand after scaling and after considering voltage dependence [MVar]

The power values in the net.res_load table are equivalent to \(P_{load}\) and \(Q_{load}\).