Static Generator

Note

Static generators should always have a positive p_mw value, since all power values are given in the generator convention. If you want to model constant power consumption, it is recommended to use a load element instead of a static generator with negative active power value. If you want to model a voltage controlled generator, use the generator element.

See also

Unit Systems and Conventions

Create Function

pandapower.create_sgen(net, bus, p_mw, q_mvar=0, sn_mva=nan, name=None, index=None, scaling=1.0, type='wye', in_service=True, max_p_mw=nan, min_p_mw=nan, max_q_mvar=nan, min_q_mvar=nan, controllable=nan, k=nan, rx=nan, id_q_capability_curve_characteristic=None, reactive_capability_curve=False, curve_style=None, current_source=True, generator_type=None, max_ik_ka=nan, kappa=nan, lrc_pu=nan, **kwargs)

Adds one static generator in table net[“sgen”].

Static generators are modelled as positive and constant PQ power. This element is used to model generators with a constant active and reactive power feed-in. If you want to model a voltage controlled generator, use the generator element instead.

gen, sgen and ext_grid in the grid are modelled in the generator system! If you want to model the generation of power, you have to assign a positive active power to the generator. Please pay attention to the correct signing of the reactive power as well (positive for injection and negative for consumption).

INPUT:

net - The net within this static generator should be created

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

p_mw (float) - The active power of the static generator (positive for generation!)

OPTIONAL:

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

sn_mva (float, None) - Nominal power of the sgen

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

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.) - An optional scaling factor to be set customly. Multiplies with p_mw and q_mvar.

type (string, None) - Three phase Connection type of the static generator: wye/delta

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

max_p_mw (float, NaN) - Maximum active power injection - necessary for controllable sgens in OPF

min_p_mw (float, NaN) - Minimum active power injection - necessary for controllable sgens in OPF

max_q_mvar (float, NaN) - Maximum reactive power injection - necessary for controllable sgens in OPF

min_q_mvar (float, NaN) - Minimum reactive power injection - necessary for controllable sgens in OPF

controllable (bool, NaN) - Whether this generator is controllable by the optimal powerflow; defaults to False if “controllable” column exists in DataFrame

k (float, NaN) - Ratio of short circuit current to nominal current

rx (float, NaN) - R/X ratio for short circuit impedance. Only relevant if type is specified as motor so that sgen is treated as asynchronous motor. Relevant for short-circuit calculation for all generator types

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”

generator_type (str, None) - can be one of “current_source” (full size converter), “async” (asynchronous generator), or “async_doubly_fed” (doubly fed asynchronous generator, DFIG). Represents the type of the static generator in the context of the short-circuit calculations of wind power station units. If None, other short-circuit-related parameters are not set

lrc_pu (float, nan) - locked rotor current in relation to the rated generator current. Relevant if the generator_type is “async”.

max_ik_ka (float, nan) - the highest instantaneous short-circuit value in case of a three-phase short-circuit (provided by the manufacturer). Relevant if the generator_type is “async_doubly_fed”.

kappa (float, nan) - the factor for the calculation of the peak short-circuit current, referred to the high-voltage side (provided by the manufacturer). Relevant if the generator_type is “async_doubly_fed”. If the superposition method is used (use_pre_fault_voltage=True), this parameter is used to pass through the max. current limit of the machine in p.u.

current_source (bool, True) - Model this sgen as a current source during short- circuit calculations; useful in some cases, for example the simulation of full- size converters per IEC 60909-0:2016.

OUTPUT:

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

EXAMPLE:

create_sgen(net, 1, p_mw=120)

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

Creates an sgen 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 static generator is connected

sn_mva (float) - rated power of the generator

cos_phi (float) - power factor cos_phi

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

OUTPUT:

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

gen, sgen, and ext_grid are modelled in the generator point of view. Active power will therefore be positive for generation, and reactive power will be negative for underexcited behavior (Q absorption, decreases voltage) and positive for overexcited behavior (Q injection, increases voltage).

Input Parameters

net.sgen

Parameter

Datatype

Value Range

Explanation

name

string

name of the static generator

type

string
naming conventions:
“PV” - photovoltaic system
“WP” - wind power system
“CHP” - combined heating and power system

type of generator

bus*

integer

index of connected bus

p_mw*

float

\(\leq\) 0

active power of the static generator [MW]

q_mvar*

float

reactive power of the static generator [MVAr]

sn_mva

float

\(>\) 0

rated power ot the static generator [MVA]

scaling*

float

\(\geq\) 0

scaling factor for the active and reactive power

max_p_mw**

float

maximum active power [MW]

min_p_mw**

float

minimum active power [MW]

max_q_mvar**

float

maximum reactive power [MVAr]

min_q_mvar**

float

minimum reactive power [MVAr]

controllable**

bool

states if sgen is controllable or not, sgen will not be used as a flexibility if it is not controllable

k***

float

\(\geq\) 0

ratio of short circuit current to nominal current

rx***

float

\(\geq\) 0

R/X ratio for short circuit impedance. Only relevant if type is specified as motor so that sgen is treated as asynchronous motor

in_service*

boolean

True / False

specifies if the generator is in service.

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 static generator reactive power capability curve

reactive_capability_curve

boolean

True / False

True if static generator has dependency on q characteristic

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

Static Generator Reactive Power Capability Curve Characteristics

The static generator reactive power capability curve characteristics provide a reference framework for determining the reactive power limits (Qmin and Qmax) of static generators based on their active power output. The reactive power capability curve data can be imported into pandapower in a tabular format, populating net.q_capability_curve_table. 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.

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.sgen 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 static generator when an optimal power flow is executed for static generators that have their “controllable” flag set to True. The variable id_q_capability_curve_characteristic in net.sgen establishes a direct reference to the id_q_capability_curve column in both net.q_capability_curve_table and net.q_capability_curve_characteristic, thereby associating each static generator with its corresponding capability curve.

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

id_q_capability_curve

p_mw

q_min_mvar

q_max_mvar

0

0

-63.00999832

-10.01000023

18.01000023

1

0

-20

-27.01000023

32.00999832

2

0

-1

-29.01000023

33.00999832

3

0

0

-28.82818222

32.73727036

4

0

10

-27.01000023

30.01000023

5

0

20

-25.01000023

28.01000023

6

0

30

-23.01000023

25.01000023

7

0

38

-21.01000023

23.01000023

8

0

50

-19.01000023

21.01000023

9

0

51.00999832

-18.01000023

20.01000023

10

1

-40.00999832

-5.010000229

5.010000229

11

1

0

-5.010000229

5.010000229

12

1

40.00999832

-5.010000229

5.010000229

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

Static Generators are modelled as PQ-buses in the power flow calculation:

alternate Text

The PQ-Values are calculated from the parameter table values as:

\begin{align*} P_{sgen} &= p\_mw \cdot scaling \\ Q_{sgen} &= q\_mvar \cdot scaling \\ \end{align*}

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!

Result Parameters

net.res_sgen

Parameter

Datatype

Explanation

p_mw

float

resulting active power demand after scaling [MW]

q_mvar

float

resulting reactive power demand after scaling [MVAr]

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