Generator

Note

A generator with positive active power represents a voltage controlled generator. If you want to model constant generation without voltage control, use the Static Generator element.

Create Function

pandapower.create.create_gen(net, bus, p_mw, vm_pu=1.0, sn_mva=nan, name=None, index=None, max_q_mvar=nan, min_q_mvar=nan, min_p_mw=nan, max_p_mw=nan, min_vm_pu=nan, max_vm_pu=nan, scaling=1.0, type=None, slack=False, id_q_capability_curve_characteristic=None, reactive_capability_curve=False, curve_style=None, controllable=nan, vn_kv=nan, xdss_pu=nan, rdss_ohm=nan, cos_phi=nan, pg_percent=nan, power_station_trafo=nan, in_service=True, slack_weight=0.0, **kwargs)

Adds a generator to the network.

Generators are always modelled as voltage controlled PV nodes, which is why the input parameter is active power and a voltage set point. If you want to model a generator as PQ load with fixed reactive power and variable voltage, please use a static generator instead.

INPUT:

net - The net within this generator should be created

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

p_mw (float, default 0) - The active power of the generator (positive for generation!)

OPTIONAL:

vm_pu (float, default 0) - The voltage set point of the generator.

sn_mva (float, NaN) - Nominal power of the generator

name (string, None) - The name for this generator

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.

scaling (float, 1.0) - scaling factor applying to the active power of the generator

type (string, None) - type variable to classify generators

reactive_capability_curve (bool, False) - True if both the id_q_capability_curve_characteristic and the curve style are present in the generator

id_q_capability_curve_characteristic (int, None) - references the index of the characteristic from the net.q_capability_curve_characteristic table (id_q_capability_curve column)

curve_style (string, None) - The curve style of the generator represents the relationship between active power (P) and reactive power (Q). It indicates whether the reactive power remains constant as the active power changes or varies dynamically in response to it, e.g. “straightLineYValues” and “constantYValue”.

controllable (bool, NaN) - True: p_mw, q_mvar and vm_pu limits are enforced for this generator in OPF; False: p_mw and vm_pu set points are enforced and limits are ignored. Defaults to True if “controllable” column exists in DataFrame.

slack_weight (float, default 0.0) - Contribution factor for distributed slack power flow calculation (active power balancing)

vn_kv (float, NaN) - Rated voltage of the generator for short-circuit calculation

xdss_pu (float, NaN) - Subtransient generator reactance for short-circuit calculation

rdss_ohm (float, NaN) - Subtransient generator resistance for short-circuit calculation

cos_phi (float, NaN) - Rated cosine phi of the generator for short-circuit calculation

pg_percent (float, NaN) - Rated pg (voltage control range) of the generator for short-circuit calculation

power_station_trafo (int, None) - Index of the power station transformer for short-circuit calculation

in_service (bool, True) - True for in_service or False for out of service

max_p_mw (float, default NaN) - Maximum active power injection - necessary for OPF

min_p_mw (float, default NaN) - Minimum active power injection - necessary for OPF

max_q_mvar (float, default NaN) - Maximum reactive power injection - necessary for OPF

min_q_mvar (float, default NaN) - Minimum reactive power injection - necessary for OPF

min_vm_pu (float, default NaN) - Minimum voltage magnitude. If not set, the bus voltage limit is taken - necessary for OPF.

max_vm_pu (float, default NaN) - Maximum voltage magnitude. If not set, the bus voltage limit is taken - necessary for OPF

OUTPUT:

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

EXAMPLE:

create_gen(net, 1, p_mw=120, vm_pu=1.02)

Input Parameters

net.gen

Parameter	Datatype	Value Range	Explanation
name	string		name of the generator
type	string	naming conventions: “sync” - synchronous generator “async” - asynchronous generator	type variable to classify generators
bus*	integer		index of connected bus
p_mw*	float	\(\leq\) 0	the real power of the generator [MW]
vm_pu*	float		voltage set point of the generator [p.u.]
sn_mva	float	\(>\) 0	nominal power of the generator [MVA]
max_q_mvar**	float		maximum reactive power of the generator [MVAr]
min_q_mvar**	float		minimum reactive power of the generator [MVAr]
scaling*	float	\(\leq\) 0	scaling factor for the active power
max_p_mw**	float		maximum active power
min_p_mw**	float		minimum active power
vn_kv***	float		rated voltage of the generator
xdss_pu***	float	\(>\) 0	subtransient generator reactance in per unit
rdss_ohm***	float	\(>\) 0	subtransient generator resistence in ohm
cos_phi***	float	:math:0 leq 1	rated generator cosine phi
in_service*	boolean	True / False	specifies if the generator is in service
power_station_trafo***	integer		index of the power station trafo (short-circuit relevant)
id_q_capability_curve_characteristic	integer		references the index of the characteristic from the q_capability_curve_characteristic
curve_style	string	either “straightLineYValues” or “constantYValue”	the style of the generator reactive power capability curve
reactive_capability_curve	boolean	True / False	True if generator has dependency on q characteristic

*necessary for executing a power flow calculation
**optimal power flow parameter
***short-circuit calculation parameter

Generator Reactive Power Capability Curve Characteristics

The generator reactive power capability curve characteristics serve as a reference for determining the reactive power limits of a generator (Qmin and Qmax) as a function of its active power output. The reactive power capability curve data can be imported into pandapower in a tabular format, populating net.q_capability_curve_table. This table can either be automatically generated via the CIM CGMES to pandapower converter and the PowerFactory to pandapower converter, provided the information is available in the Equipment (EQ) profile and the “Capability curve” section, respectively, or it can be manually defined by the user.

Q capability curve characteristic objects are then generated from net.q_capability_curve_table, populating net.q_capability_curve_characteristic. The characteristics can either be automatically generated via the CIM CGMES to pandapower converter or the PowerFactory to pandapower converter, or they can be created by the user using the pandapower.control.util.create_q_capability_curve_characteristics_object function, provided that the q_capability_curve_table is previously defined in the network case.

If the variable reactive_capability_curve in net.gen is set to True, it indicates that pairs of P vs Qmin/Qmax values and the corresponding characteristic are defined in net.q_capability_curve_table and net.q_capability_curve_characteristic respectively. This overrides the default reactive power limits of the generator when i) a power flow is executed and the enforce_q_lims option is enabled; or ii) an optimal power flow is executed for generators that have their “controllable” flag set to True. The variable id_q_capability_curve_characteristic in net.gen establishes a link to the id_q_capability_curve column in both net.q_capability_curve_table and net.q_capability_curve_characteristic, associating each generator with its respective capability curve.

Below is an example of a q_capability_curve_table, populated for two sample generators.

	id_q_capability_curve	p_mw	q_min_mvar	q_max_mvar
0	0	-20.01000023	-360.0100098	310.0100098
1	0	0	-360.0100098	307.9073181
2	0	389	-360.0100098	267.0100098
3	0	555	-251.0099945	251.0099945
4	0	574	-181.0099945	181.0099945
5	0	583.0100098	-128.0099945	128.0099945
6	1	-331.0100098	-0.01	0.01
7	1	-298	-134.0099945	134.0099945
8	1	-198	-265.0100098	228.0099945
9	1	-66.19999695	-323.0100098	257.0100098
10	1	-0.100000002	-323.0100098	261.0100098
11	1	0	-323.0100098	261.0100098
12	1	0.100000002	-323.0100098	261.0100098
13	1	66.19999695	-323.0100098	257.0100098
14	1	198	-265.0100098	228.0099945
15	1	298	-134.0099945	134.0099945
16	1	331.0100098	-0.01	0.01

The table below illustrates an example of a q_capability_curve_characteristic table populated for two generators.

	id_q_capability_curve	q_max_characteristic	q_min_characteristic
0	0	Characteristic	Characteristic
1	1	Characteristic	Characteristic

Note

reactive_capability_curve has to be set to True, and id_q_capability_curve_characteristic and curve_style variables need to be populated in order to consider the reactive power limits of the corresponding characteristic.
Each generator supports only a single reactive_capability_curve.
In this version, only two types of generator reactive power capability characteristics are supported: 1. constantYValue: The reactive power values are assumed constant until the next curve point and prior to the first curve point. 2. straightLineYValues: The reactive power values are assumed to be a straight line between values.
Linear interpolation is employed to determine Qmin and Qmax based on the given active power dispatch for the above two curve types.

The function pandapower.control.util.q_capability_curve_table_diagnostic is available to perform sanity checks on the generator reactive power capability curve table.

Electric Model

Generators are modelled as PV-nodes in the power flow:

Voltage magnitude and active power are defined by the input parameters in the generator table:

\begin{align*} P_{gen} &= p\_mw * scaling \\ v_{bus} &= vm\_pu \end{align*}

Result Parameters

net.res_gen

Parameter	Datatype	Explanation
p_mw	float	resulting active power demand after scaling [MW]
q_mvar	float	resulting reactive power demand after scaling [MVAr]
va_degree	float	generator voltage angle [degree]
vm_pu	float	voltage at the generator [p.u.]

The power flow returns reactive generator power and generator voltage angle:

\begin{align*} p\_mw &= P_{gen} \\ q\_mvar &= Q_{gen} \\ va\_degree &= \angle \underline{v}_{bus} \\ vm\_degree &= |\underline{v}_{bus}| \end{align*}

Note

If the power flow is run with the enforce_q_lims option and the generator reactive power exceeds / falls short of the maximum / minimum reactive power limit, the generator is converted to a static generator with the maximum / minimum reactive power as constant reactive power generation. The voltage at the generator bus is then no longer equal to the voltage set point defined in the parameter table.