Frequently used objects¶

Connections¶

The connections object is one of the main objects of the LtmApi. It is used to connect objects. For example:

Busbars to DC Lines, Hydro power, Loads
topology of detailed hydropower modules in API Waterways and hydro topology

Connections parameters¶
Parameter	Datatype	Description
from	string	name of object from connection point
to	string	name of object to connection point
comment	string	optional comment

Click arrow-head to see connections examples below.

Connections examples

"connections": [
    {
        "from": "pumpekraft", // busbar
        "to": "PUMPE_TEV_DC"  // dc_line
    },
    {
        "from": "market_step", // market step
        "to": "pumpekraft"     // busbar
    },
    {
        "from": "PUMPE_TEV_DC", // dc_line
        "to": "tev"             // busbar
    },
    {
        "from": "FLAT",         // load
        "to": "pumpekraft"      // busbar
    },
    {
        "from": "upper_main",   // reservoir
        "to": "pumpekraft"      // busbar
    },
    {
        "from": "upper_main",   // reservoir
        "to": "plant"           // hydropower plant
    }
]

Busbars¶

The busbar object is a key object used to define the areas of the LTM. The busbar parameters are listed below. The parameters in bold are required and the others are optional.

Busbar Parameters¶
Parameter	Datatype	Unit
name	string	Object/Busbar name
id	int	Output
water_value_weights	water_value_weights	Used to change the default scenario weights in the Water Value method.
spill_cost	double_optional	Spill cost price. Default value = 0.01. This value must be the system’s lowest price.
load_penalty	double_optional	Load penalty price. Default value = 3000. The value must be the system’s highest price.
max_iterations	int_optional	Max number of iterations for the water value calculation. Default value = 40. Water Value method.
precision	double_optional	Convergence criterion for the water value calculation. Default value = 0.001. Water Value method.
feedback_factors	feedback_factors	Used in the EMPS model strategy and calibration. Default feedback factors are generated automatically by the EMPS. Feedback factors are very important for the results!
has_detailed_grid	bool	Use in Samnett to sort the list of areas with detailed grid.
#comment	string_optional	Optional comment
metadata	json	Output

A minimal example is show below (collapsed).

Burbars examples

"busbars": [
    {
        "name": "numedal",
        "spill_cost": 0.001,    // optional
        "max_iterations": 500,  // optional
        "precision": 0.0001     // optional
    },
    {
        "name": "tev"
    },
    {
        "name": "otra"
    }
]

Common attributes¶

This section gives short descriptions of common attributes not described elsewhere in the LtmApi documentation.

ownership¶

ownership parameters¶
Parameter	Datatype	Description
ownership	float	Optional, the ownership share of the system element in percent. Default value is 100 %.

The production in the power plants is scaled relative to the ownership, only the energy equivalent (discharge curve) is scaled. However, it is possible to extract the results for the specified ownership of the system or the total system.

inflow_series¶

The inflow_series parameters are listed in the table below.

Inflow time series parameters¶
Parameter	Datatype	Description
name	string	Object name
series	Txy	An inflow series can be defined and used as a reference on Plant or Reservoir. Unit is [m3/s]. See also Inflow.

Examples¶

Minimal example is provided below (click arrow-head to uncollapse).

inflow_series

"inflow_series": [
    {
        "name": "yearly_inflow_profile",
        "series": {
            "timestamps": [
                "1981-01-01T00:00:00Z",
                "1982-01-01T00:00:00Z",
                "1983-01-01T00:00:00Z",
                "1984-01-01T00:00:00Z",
                "1985-01-01T00:00:00Z",
                "1986-01-01T00:00:00Z",
                "1987-01-01T00:00:00Z",
                "1988-01-01T00:00:00Z",
            ],
            "scenarios": [
                [
                    0.47,
                    0.49,
                    0.40,
                    0.43,
                    0.39,
                    0.46,
                    0.44,
                    0.43
                ]
            ]
        }
    }
]

Usage example for plant is below (click arrow-head to uncollapse).

plant_inflow_series

"plants": [
  {
      "name": "plant",
      "discharge_energy_equivalent": {
          "scenarios": [
              [
                  0.12
              ]
          ]
      },
      "pq_curves": {
          "2024-01-01T00:00:00Z": {
              "y": [
                  0.0,
                  9.89
              ],
              "x": [
                  0.0,
                  24.6
              ]
          }
      },
      "average_unregulated_inflow": 0.6,
      "gross_head": 40.0,
      "tailrace_elevation": 1030,
      "unregulated_inflow_name": "yearly_inflow_profile"
  }
]

Similarly, using an inflow_series on a reservoir object is performed by the regulated_inflow_name attribute.