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.

See also

Unit Systems and Conventions

Create Function

pandapower.create.create_load(net, bus, p_mw, q_mvar=0, const_z_p_percent=0, const_i_p_percent=0, const_z_q_percent=0, const_i_q_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, **kwargs)

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.

Parameters:

  • net (pandapowerNet) – The net within this load should be created

  • bus (int | integer) – The bus id to which the load is connected

  • p_mw (float) –

    The active power of the load

    • positive value -> load

    • negative value -> generation

  • q_mvar (float) – The reactive power of the load

  • const_z_p_percent (float) – percentage of p_mw that will be associated to constant impedance load at rated voltage

  • const_i_p_percent (float) – percentage of p_mw that will be associated to constant current load at rated voltage

  • const_z_q_percent (float) – percentage of q_mvar that will be associated to constant impedance load at rated voltage

  • const_i_q_percent (float) – percentage of q_mvar that will be associated to constant current load at rated voltage

  • sn_mva (float) – Nominal power of the load

  • name (str | None) – The name for this load

  • scaling (float) – An OPTIONAL scaling factor. Multiplies with p_mw and q_mvar.

  • type (Literal['wye', 'delta']) – type variable to classify the load: wye/delta

  • index (int | integer | 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 (bool) – True for in_service or False for out of service

  • max_p_mw (float) – Maximum active power load - necessary for controllable loads in for OPF

  • min_p_mw (float) – Minimum active power load - necessary for controllable loads in for OPF

  • max_q_mvar (float) – Maximum reactive power load - necessary for controllable loads in for OPF

  • min_q_mvar (float) – Minimum reactive power load - necessary for controllable loads in OPF

  • controllable (bool | float) – States, whether a load is controllable or not. Only respected for OPF; defaults to False if “controllable” column exists in DataFrame

Returns:

The ID of the created load

Return type:

int | integer

Example

>>> create_load(net, bus=0, p_mw=10., q_mvar=2.)
pandapower.create.create_loads(net, buses, p_mw, q_mvar=0, const_z_p_percent=0, const_i_p_percent=0, const_z_q_percent=0, const_i_q_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, **kwargs)

Adds a number of loads 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.

Parameters:

  • net (pandapowerNet) – The net within this load should be created

  • buses (Sequence) – A list of bus ids to which the loads are connected

  • p_mw (float | Iterable[float]) –

    The active power of the loads

    • positive value -> load

    • negative value -> generation

  • q_mvar (float | Iterable[float]) – The reactive power of the loads

  • const_z_p_percent (float | Iterable[float]) – percentage of p_mw that will be associated to constant impedance loads at rated voltage

  • const_i_p_percent (float | Iterable[float]) – percentage of p_mw that will be associated to constant current load at rated voltage

  • const_z_q_percent (float | Iterable[float]) – percentage of q_mvar that will be associated to constant impedance loads at rated voltage

  • const_i_q_percent (float | Iterable[float]) – percentage of q_mvar that will be associated to constant current load at rated voltage

  • sn_mva (float | Iterable[float]) – Nominal power of the loads

  • name (Iterable[str] | None) – The name for this load

  • scaling (float | Iterable[float]) – An OPTIONAL custom scaling factor. Multiplies with p_mw and q_mvar.

  • type (Literal['wye', 'delta']) – type variable to classify the load

  • index (int | integer | Iterable[int | integer] | None) – Force a specified ID if it is available. If None, the index is set to a range between one higher than the highest already existing index and the length of loads that shall be created.

  • in_service (bool | Iterable[bool]) – True for in_service or False for out of service

  • max_p_mw (float | Iterable[float]) – Maximum active power load - necessary for controllable loads in for OPF

  • min_p_mw (float | Iterable[float]) – Minimum active power load - necessary for controllable loads in for OPF

  • max_q_mvar (float | Iterable[float]) – Maximum reactive power load - necessary for controllable loads in for OPF

  • min_q_mvar (float | Iterable[float]) – Minimum reactive power load - necessary for controllable loads in OPF

  • controllable (bool | Iterable[bool] | float) – States, whether a load is controllable or not. Only respected for OPF Defaults to False if “controllable” column exists in DataFrame

Returns:

The IDs of the created loads

Return type:

ndarray[tuple[Any, …], dtype[int | integer]]

Example

>>> create_loads(net, buses=[0, 2], p_mw=[10., 5.], q_mvar=[2., 0.])
pandapower.create.create_load_from_cosphi(net, bus, sn_mva, cos_phi, mode, **kwargs)

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

Parameters:

  • net (pandapowerNet) – The net within this static generator should be created

  • bus (int | integer) – 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 (Literal['underexcited', 'overexcited']) –

    • “underexcited” (Q absorption, decreases voltage)

    • ”overexcited” (Q injection, increases voltage)

  • **kwargs – any parameter from create_load, as these get passed to the create_load function

Returns:

The ID of the created load

Return type:

int | integer

Load elements are modeled from a consumer point of view. Active power will therefore always be positive, reactive power will be positive for underexcited behavior (Q absorption, decreases voltage) and negative for overexcited behavior (Q injection, increases voltage).

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_p_percent*

float

\([0,100]\)

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

const_i_p_percent*

float

\([0,100]\)

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

const_z_q_percent*

float

\([0,100]\)

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

const_i_q_percent*

float

\([0,100]\)

percentage of 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 pandapower. 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. This is considered separately for active and reactive power:

\[\begin{split}z_{const_p} &= \frac{const\_z\_p\_percent}{100} \\ z_{const_q} &= \frac{const\_z\_q\_percent}{100} \\ i_{const_p} &= \frac{const\_i\_p\_percent}{100} \\ i_{const_q} &= \frac{const\_i\_q\_percent}{100} \\ p_{const_p} &= \frac{100 - const\_z\_p\_percent - const\_i\_p\_percent}{100} \\ p_{const_q} &= \frac{100 - const\_z\_q\_percent - const\_i\_q\_percent}{100}\end{split}\]

The load power values are then defines as:

\[\begin{split}P_{load} &= p\_mw \cdot scaling \cdot (p_{const_p} + z_{const_p} \cdot V^2 + i_{const_p} \cdot V ) \\ Q_{load} &= q\_mvar \cdot scaling \cdot (p_{const_q} + z_{const_q} \cdot V^2 + i_{const_q} \cdot V)\end{split}\]

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 \(Q_{load}\).