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, **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.

INPUT:

net - The net within this load should be created

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

p_mw (float) - The active power of the load

positive value -> load
negative value -> generation

OPTIONAL:

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. Multiplies with p_mw and q_mvar.

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; defaults to False if “controllable” column exists in DataFrame

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) - “underexcited” (Q absorption, decreases voltage) or “overexcited” (Q injection, increases voltage)

OPTIONAL:

same as in create_load, keyword arguments are passed to the create_load function

OUTPUT:

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

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_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):

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 \(Q_{load}\).