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node is a point in the grid. Physically a node can be a busbar, a joint, or other similar component.
Input
name
data type
unit
description
required
update
valid values
u_rated
double
volt (V)
rated line-line voltage
✔
❌
> 0
Steady state output
name
data type
unit
description
u_pu
RealValueOutput
-
per-unit voltage magnitude
u_angle
RealValueOutput
rad
voltage angle
u
RealValueOutput
volt (V)
voltage magnitude, line-line for symmetric calculation, line-neutral for asymmetric calculation
p
RealValueOutput
watt (W)
active power injection
q
RealValueOutput
volt-ampere-reactive (var)
reactive power injection
The `p` and `q` output of injection follows the `generator` reference direction as mentioned in
{hoverxreftooltip}`user_manual/data-model:Reference Direction`
branch is the abstract base type for the component which connects two different nodes. For each branch two switches
are always defined at from- and to-side of the branch. In reality such switches may not exist. For example, a cable
usually permanently connects two joints. In this case, the attribute from_status and to_status is always 1.
Input
name
data type
unit
description
required
update
valid values
from_node
int32_t
-
ID of node at from-side
✔
❌
a valid node ID
to_node
int32_t
-
ID of node at to-side
✔
❌
a valid node ID
from_status
int8_t
-
connection status at from-side
✔
✔
0 or 1
to_status
int8_t
-
connection status at to-side
✔
✔
0 or 1
Steady state output
name
data type
unit
description
p_from
RealValueOutput
watt (W)
active power flowing into the branch at from-side
q_from
RealValueOutput
volt-ampere-reactive (var)
reactive power flowing into the branch at from-side
i_from
RealValueOutput
ampere (A)
current at from-side
s_from
RealValueOutput
volt-ampere (VA)
apparent power flowing at from-side
p_to
RealValueOutput
watt (W)
active power flowing into the branch at to-side
q_to
RealValueOutput
volt-ampere-reactive (var)
reactive power flowing into the branch at to-side
i_to
RealValueOutput
ampere (A)
current at to-side
s_to
RealValueOutput
volt-ampere (VA)
apparent power flowing at to-side
loading
double
-
relative loading of the line, 1.0 meaning 100% loaded.
Short circuit output
name
data type
unit
description
i_from
RealValueOutput
ampere (A)
current at from-side
i_from_angle
RealValueOutput
rad
current angle at from-side
i_to
RealValueOutput
ampere (A)
current at to-side
i_to_angle
RealValueOutput
rad
current angle at to-side
Line
type name: 'line'
line is a {hoverxreftooltip}user_manual/components:branch with specified serial impedance and shunt admittance. A cable is
also modeled as line. A line can only connect two nodes with the same rated voltage.
If i_n is not provided, loading of line will be a nan value.
Input
name
data type
unit
description
required
update
valid values
r1
double
ohm (Ω)
positive-sequence serial resistance
✔
❌
r1 and x1 cannot be both zero
x1
double
ohm (Ω)
positive-sequence serial reactance
✔
❌
r1 and x1 cannot be both zero
c1
double
farad (F)
positive-sequence shunt capacitance
✔
❌
tan1
double
-
positive-sequence shunt loss factor (tan𝛿)
✔
❌
r0
double
ohm (Ω)
zero-sequence serial resistance
✨ only for asymmetric calculations
❌
r0 and x0 cannot be both zero
x0
double
ohm (Ω)
zero-sequence serial reactance
✨ only for asymmetric calculations
❌
r0 and x0 cannot be both zero
c0
double
farad (F)
zero-sequence shunt capacitance
✨ only for asymmetric calculations
❌
tan0
double
-
zero-sequence shunt loss factor (tan𝛿)
✨ only for asymmetric calculations
❌
i_n
double
ampere (A)
rated current
❌
❌
> 0
Link
type name: link
link is a {hoverxreftooltip}user_manual/components:branch which usually represents a short internal cable/connection between
two busbars inside a substation. It has a very high admittance (small impedance) which is set to a fixed per-unit value
(equivalent to 10e6 siemens for 10kV network). Therefore, it is chosen by design that no sensors can be coupled to a link.
There is no additional attribute for link.
Transformer
transformer is a {hoverxreftooltip}user_manual/components:branch which connects two nodes with possibly different voltage
levels.
clock number of phase shift. Even number is not possible if one side is Y(N) winding and the other side is not Y(N) winding. Odd number is not possible, if both sides are Y(N) winding or both sides are not Y(N) winding.
branch3 is the abstract base type for the component which connects three different nodes. For each branch3 three
switches are always defined at side 1, 2, or 3 of the branch. In reality such switches may not exist.
Input
name
data type
unit
description
required
update
valid values
node_1
int32_t
-
ID of node at side 1
✔
❌
a valid node ID
node_2
int32_t
-
ID of node at side 2
✔
❌
a valid node ID
node_3
int32_t
-
ID of node at side 3
✔
❌
a valid node ID
status_1
int8_t
-
connection status at side 1
✔
✔
0 or 1
status_2
int8_t
-
connection status at side 2
✔
✔
0 or 1
status_3
int8_t
-
connection status at side 3
✔
✔
0 or 1
Steady state output
name
data type
unit
description
p_1
RealValueOutput
watt (W)
active power flowing into the branch at side 1
q_1
RealValueOutput
volt-ampere-reactive (var)
reactive power flowing into the branch at side 1
i_1
RealValueOutput
ampere (A)
current at side 1
s_1
RealValueOutput
volt-ampere (VA)
apparent power flowing at side 1
p_2
RealValueOutput
watt (W)
active power flowing into the branch at side 2
q_2
RealValueOutput
volt-ampere-reactive (var)
reactive power flowing into the branch at side 2
i_2
RealValueOutput
ampere (A)
current at side 2
s_2
RealValueOutput
volt-ampere (VA)
apparent power flowing at side 2
p_3
RealValueOutput
watt (W)
active power flowing into the branch at side 3
q_3
RealValueOutput
volt-ampere-reactive (var)
reactive power flowing into the branch at side 3
i_3
RealValueOutput
ampere (A)
current at side 3
s_3
RealValueOutput
volt-ampere (VA)
apparent power flowing at side 3
loading
double
-
relative loading of the branch, 1.0 meaning 100% loaded.
Short circuit output
name
data type
unit
description
i_1
RealValueOutput
ampere (A)
current at side 1
i_1_angle
RealValueOutput
rad
current angle at side 1
i_2
RealValueOutput
ampere (A)
current at side 2
i_2_angle
RealValueOutput
rad
current angle at side 2
i_3
RealValueOutput
ampere (A)
current at side 3
i_3_angle
RealValueOutput
rad
current angle at side 3
Three-Winding Transformer
three_winding_transformer is a {hoverxreftooltip}user_manual/components:branch3 connects three nodes with possibly different
voltage levels.
Input
name
data type
unit
description
required
update
valid values
u1
double
volt (V)
rated voltage at side 1
✔
❌
> 0
u2
double
volt (V)
rated voltage at side 2
✔
❌
> 0
u3
double
volt (V)
rated voltage at side 3
✔
❌
> 0
sn_1
double
volt-ampere (VA)
rated power at side 1
✔
❌
> 0
sn_2
double
volt-ampere (VA)
rated power at side 2
✔
❌
> 0
sn_3
double
volt-ampere (VA)
rated power at side 3
✔
❌
> 0
uk_12
double
-
relative short circuit voltage across side 1-2, 0.1 means 10%
✔
❌
>= pk_12 / min(sn_1, sn_2) and > 0 and < 1
uk_13
double
-
relative short circuit voltage across side 1-3, 0.1 means 10%
✔
❌
>= pk_13 / min(sn_1, sn_3) and > 0 and < 1
uk_23
double
-
relative short circuit voltage across side 2-3, 0.1 means 10%
appliance is an abstract user which is coupled to a node. For each appliance a switch is defined between
the appliance and the node. The reference direction for power flows is mentioned in
{hoverxreftooltip}user_manual/data-model:Reference Direction.
source is an {hoverxreftooltip}user_manual/components:appliance representing the external network with a
Thévenin's equivalence. It has an infinite voltage source
with an internal impedance. The impedance is specified by convention as short circuit power.
Input
name
data type
unit
description
required
update
valid values
u_ref
double
-
reference voltage in per-unit
✨ only for power flow
✔
> 0
u_ref_angle
double
rad
reference voltage angle
❌ default 0.0
✔
sk
double
volt-ampere (VA)
short circuit power
❌ default 1e10
❌
> 0
rx_ratio
double
-
R to X ratio
❌ default 0.1
❌
>= 0
z01_ratio
double
-
zero sequence to positive sequence impedance ratio
❌ default 1.0
❌
> 0
Generic Load and Generator
type name: generic_load_gen
generic_load_gen is an abstract load/generation {hoverxreftooltip}user_manual/components:appliance which contains only the
type of the load/generation with response to voltage.
There are four concrete types of load/generator. They share similar attributes: specified active/reactive power.
However, the reference direction and meaning of RealValueInput is different, as shown in the table below.
shunt is an {hoverxreftooltip}user_manual/components:appliance with a fixed admittance (impedance). It behaves similar to a
load/generator with type const_impedance.
sensor is an abstract type for all the sensor types. A sensor does not have any physical meaning. Rather, it provides
measurement data for the state estimation algorithm. The state estimator uses the data to evaluate the state of the grid
with the highest probability.
Input
name
data type
unit
description
required
update
valid values
measured_object
int32_t
-
ID of the measured object
✔
❌
a valid object ID
Generic Voltage Sensor
type name: generic_voltage_sensor
generic_voltage_sensor is an abstract class for symmetric and asymmetric voltage sensor and derived from
{hoverxreftooltip}user_manual/components:sensor. It measures the magnitude and (optionally) the angle of the voltage of
a node.
Input
name
data type
unit
description
required
update
valid values
u_sigma
double
volt (V)
standard deviation of the measurement error. Usually this is the absolute measurement error range divided by 3.
✨ only for state estimation
✔
> 0
Voltage Sensor Concrete Types
There are two concrete types of voltage sensor. They share similar attributes:
the meaning of RealValueInput is different, as shown in the table below. In a sym_voltage_sensor the measured
voltage is a line-to-line voltage. In a asym_voltage_sensor the measured voltage is a 3-phase line-to-ground voltage.
type name
meaning of RealValueInput
sym_voltage_sensor
double
asym_voltage_sensor
double[3]
Input
name
data type
unit
description
required
update
valid values
u_measured
RealValueInput
volt (V)
measured voltage magnitude
✨ only for state estimation
✔
> 0
u_angle_measured
RealValueInput
rad
measured voltage angle (only possible with phasor measurement units)
❌
✔
Steady state output
name
data type
unit
description
u_residual
RealValueOutput
volt (V)
residual value between measured voltage magnitude and calculated voltage magnitude
u_angle_residual
RealValueOutput
rad
residual value between measured voltage angle and calculated voltage angle (only possible with phasor measurement units)
Generic Power Sensor
type name: generic_power_sensor
power_sensor is an abstract class for symmetric and asymmetric power sensor and is derived from
{hoverxreftooltip}user_manual/components:sensor. It measures the active/reactive power flow of a terminal. The terminal is
either connecting an appliance and a node, or connecting the from/to end of a branch (except link) and a node. In case of a
terminal between an appliance and a node, the power {hoverxreftooltip}user_manual/data-model:Reference Direction in the
measurement data is the same as the reference direction of the appliance. For example, if a power_sensor is
measuring a source, a positive p_measured indicates that the active power flows from the source to the node.
1. Due to the high admittance of a `link` it is chosen that a power sensor cannot be coupled to a `link`, even though a link is a `branch`
2. The node injection power sensor gets placed on a node.
In the state estimation result, the power from this injection is distributed equally among the connected appliances at that node.
Because of this distribution, at least one appliance is required to be connected to the node where an injection sensor is placed for it to function.