Terms

This section describes the list of commonly used terms within SAInt. The terms are divided into three categories: Network, Scenario, and Solution.

1. Network

The section describes network-related terms.

Network

A network is a directed graph consisting of a set of nodes, branches, and externals that are connected to one another. A network may contain other types of auxiliary objects that are subs of or represent relations between nodes, branches, and externals. A network contains a description of all geometric, topological information, relational, and static properties of all network objects, which typically do not change during the execution of a scenario. A SAInt network is saved with extension (*.*net).

Hub Network

A hub network contains properties and topological information of the hubs facilities. A hub network file is saved with extension(*.hubs).

Sub

A sub (also referred to as sub-network, subnet, or subsystem) is a subset of nodes, branches, and externals of a network. A sub is branch-oriented, i.e., only branches can be assigned to a sub, and every branch belongs to only one sub. The FromNode and ToNode of a branch, as well as the externals connected to these two nodes, are implicitly added to the sub. Thus, nodes connecting branches of different sub and the externals connected to these nodes are always included in multiple sub.

Zone

A zone is a subset of nodes, branches, and externals of a network. In contrast to sub, zones are node-oriented, i.e., only nodes can be assigned to a zone, and every node belongs to one zone. Branches with a FromNode and ToNode belonging to the same zone are implicitly added to the corresponding zone. In contrast, branches with a FromNode and ToNode belonging to two different zones do not belong to any zone. Externals are also implicitly added to the zone of the node they are connected to.

Group

A group is a subset of different child object types (e.g., nodes, branches, externals, fuels, ancillary services, hydro plants, constraints, etc.) of the whole network. In contrast to sub and zones, groups do not follow any specific assignment rules. Thus, a child object can be assigned to multiple groups.

Node

A node represents a (physical) location within a network model where energy (gas, electricity, etc.) can be injected or extracted from the network.

Branch

A branch is a directed connection between a pair of nodes (locations). One of the two nodes is referred to as FromNode and the other as ToNode. The flow direction in a branch is positive if the flow goes from the FromNode to the FromNode, otherwise the direction is negative. A branch is used to model facilities that have an inlet, an outlet, and a flow direction, such as electric lines, pipelines, and valves.

External

An external is a directed connection to a single node that allows the extraction and injection of energy at that node. An external is used to model demand, supply, and storage in a network.

Object

An object is a unique entity, element, or instance of a network model. Objects can be subdivided into different object types, such as nodes, branches, externals, networks, sub, zones, and groups.

Object Name

Every object in a network is defined by a unique name. For example an electric node has a name 'AUSTRIA'.

Object Type

Every object in a network is identified by its unique object type code. For example, an electric node has an object type ENO, a gas branch has an object type GBR.

Object ID

The combination of object name and object type code is referred to as object ID. For example, ENO.PARIS is the unique object ID of an electric node named PARIS, GSUP.AUSTRIA is the unique object ID of a gas supply named AUSTRIA.

Property

A property is a description of an attribute or characteristic of an object. Every property of an object has a distinct name and a unit type.

Property Name

The property name is the name defined for a property in its respective class within the source code. In most cases, the PropertyName is the same as the Extension.

Display Name

The display name of a property is a more descriptive designation than the property name or extension and is therefore typically composed of a greater number of characters. The display name of a property is displayed in the property editor. For example, default maximum active power has the display name 'DefMaxActivePower'.

Unit

The units of different properties are linked to a unique unit type. For example: the unit type ('Active Power') is linked to properties Maximum Active Power (PMAX), and Minimum Active Power (PMIN); the unit type ('Flow') is linked to properties InOrOutflow(Q), and FlowNotServed (QNS).

Extension

An extension is an acronym or abbreviation representing the input or output property of an object. An object can have multiple extensions. Objects of the same object type have a set of identical extensions. For example, an extension of a voltage magnitude of a node is defined as (VM). The extensions of a property are visible in the property editor within () brackets.

Display Name

The display name of a property is a more descriptive designation than the property name or extension and is therefore typically composed of a greater number of characters. The display name of a property is displayed in the property editor.

Display Unit

The display unit is the currently selected unit option for a specific unit type (selection in the unit tab of the settings dialog). In the GUI, property values are typically displayed in the display unit of the unit type assigned to the property.

2. Scenario

The section describes scenario-related terms.

Scenario

A scenario is a case study performed on a network. A network can be linked to an infinite number of scenarios. A scenario can either be a simulation or an optimization of a unique case study. A SAInt scenario is saved with (*.sce) extension.

Time Window

The time window is the time duration between the start time and end time of a scenario.

Time Horizon

The time horizon is a fraction of the scenario time window considered for a consecutive optimization in a DCUCOPF scenario. The time window is a multiple of the time horizon, i.e., time window divided by time horizon must be an integer greater than or equal to one. This integer represents the number of consecutive optimizations for a DCUCOPF scenario. Each consecutive optimization covers a time interval of the scenario time window equal to the time horizon.

Time Step

A time step is a fraction of the scenario time window used for discretizing the scenario time window into distinct time points which are calculated for the variables. The time window is a multiple of the time step, i.e., time window divided by time step must be an integer greater than or equal to one.

Time Look Ahead

A look ahead, look ahead time, or time look ahead is a time duration added to the time interval considered in the consecutive optimization for a DCUCOPF scenario. It assists the mathematical model in finding a more realistic solution for the commitments of generators and the operation of storages close to the end of a time horizon as it indicates that the operation of the generators does not end at the end of the time horizon. The total time interval for a consecutive optimization is composed of the time horizon and the look ahead. The lookahead typically has a smaller time resolution or a longer time step than the time horizon.

Time Step Look Ahead

A time step look ahead is a fraction of the scenario time look ahead used for discretizing the scenario time look ahead into distinct time points which are calculated for the variables. The time look ahead is a multiple of the time step look ahead, i.e., time look ahead divided by time step look ahead must be an integer greater than or equal to one.

Event

An event is a definition of a change in the setting, control, or constraint of an object (boundary conditions) at a specific time during the execution of a scenario.

Profile

A profile is a collection of ordered equidistant data points that includes information on how these data points are processed in terms of the time step, interpolation, sampling, and periodicity when assigned to an event.

SetPoint Parameter

A setpoint is a desired value prescribed for a variable in the mathematical model describing a scenario. A variable may differ from its setpoint if meeting the setpoint would violate a constraint.

State Parameter

The state parameter defines the operating state of a network object. For example, ON or OFF state.

Constraint Parameter

A constraint parameter defines the upper or lower limit of a solution variable. For example, the maximum active power generation (PMAX).

InitialState Parameter

Sets values for the initial state of a scenario. For example, the active power generation at the initial time point event for a generator (PINI) or the storage inventory at the initial time point event for a gas storage (INV).

Reference Parameter

These parameters do not influence the outcome of the computation but are used for comparing or visualizing results. For example, the reference voltage magnitude event for an electric node (VMREF).

Setting Parameter

This parameter changes the simulation settings used in the solver. For example, it can apply a transport model for the DCUCOPF scenario (NODROP) or consider losses in the DCUCOPF scenario event for an electric network (INCLUDELOSS).

Display Time

The display time is the current scenario time selected in the GUI that is used to display scenario results for different objects in object tables, property editor, labels, expressions etc.

3. Solution

The section describes solution-related terms.

Simulation

A simulation is a mathematical model composed of a set of linear and/or non-linear equations describing the relations between variables and parameters of a network model. These equations are derived from (physical) laws governing the behavior and interactions of components and facilities in the network model. The derived equations may be simplified based on suitable assumptions for the specific application the model is used for. In contrast to an optimization, a simulation has no objective function, i.e., a simulation does not give the best feasible solution for the variables for a given objective, but a solution that solves the set of equations and boundary conditions. The execution of a scenario is also called simulation in SAInt.

Optimization

An optimization is a mathematical model composed of a linear or non-linear objective function, binary, integer, or continuous decision variables, and linear or non-linear equality and inequality constraints. The goal of an optimization is to find a solution for the decision variables that minimizes/maximizes the objective function and fulfills all equality and inequality constraints. The execution of an optimization is called a simulation in SAInt.

Solution

A solution describes the computed results for the variables of a network model for every computed time point of a scenario. It can be regarded as an accumulation of states for every computed scenario time point. The solution of a scenario is saved to a solution file with the file extension `*.*so`l (e.g., *.esol for electric network solution, *.gsol for gas network solution, and *.tsol for thermal network solution).

State/Condition

A state or condition describes the computed results for the variables of a network model at a specific time point and for a specific scenario type. It can be regarded as a snapshot of the scenario results for a network model at a specific time point. A state is saved to a state or condition file with the file extension *.*con (e.g., *.econ for electric network state or condition, *.gcon for gas network state or condition, and *.tcon for thermal network state or condition).

Logs

The logs in SAInt refers to the information related to operations and processes in SAInt. It encompasses all activities within the network and its scenarios including the simulation logs.