webgme-gridlabd

Metamodel, visualization, and model generators for gridlab-d in WebGME.

This document covers how to use the WebGME modeling environment for creating, importing, updating, and rendering (serializing) Gridlab-D models (GLM format).

Note: this document does not describe how Gridlab-D works, merely how the WebGME interface works for importing, creating, and rendering GLM files. Users who have questions about what a specific attribute of a specific Gridlab-D object type means are referred to the Gridlab-D Wiki.

Table of Contents:

• WebGME Interface
• META
• Models
• Plugins
  • UpdateGLDMeta
  • ImportGLM
  • GenerateGLM
  • SimulateWithGridlabD
  • SimulateTES
  • SimulateTESCluster
• Creating a Gridlab-D Model from Scratch

WebGME interface

The webgme interface allows the visual creation and editing of models, where the top level (ROOT) of the webgme interface can contain models, and each model represents a GLM (gridlabd model).

Note: since the WebGME interface is designed to graphically model and represent GLM files, ancillary files which a single GLM file can include are not directly modeled. To capture those files as part of the webgme model, please create an Include object (with the name of the file as the name of the object) and upload the relevant file sa the new Include object's file attribute (by clicking on the attribute). Then when a user wants to access that file they can simply click on that attribute to download it from the server.

META

The meta for webgme-gridlabd is broken up into many parts, with the base meta (GridlabD) being the only hand-crafted part of the meta. The base meta defines what a model is, what it can contain such as objects, globals, variables, modules, classes, etc. The types defined in this aspect are the most basic class definitions from which all other gridlabd types derive (e.g. a node derives from a powerflow object which derives from object).

The specific metas for each of the different gridlab-d modules are defined in their own separate sheets, which are automatically created when running the UpdateGLDMeta plugin (described below). An example of an imported meta can be found below (note that when it is imported it is not automatically laid out, so some manual layout of the objects may be necessary to better visualize the meta).

Models

Within a model, you have the ability to create nodes, links between nodes (e.g. overhead lines, transformers), schedules, loads, etc. just as you would in a gridlab-d model. Any connection objects between nodes are visualized as lines connecting those nodes.

Below is a simple 4 node powerflow model which was automatically imported from a gridlab-d model (GLM) file that exists in the gridlabd repository.

Below is a more complex example showing two communities of houses connected to two generators. Each house has water heaters, HVAC systems, and controllers.

Finally, here is a very large (comparatively) model which was created and automatically laid out using the ImportGLM plugin, from the Taxonomy Feeder R1-12.47 model in the Gridlab-D source code repository.

Plugins

This section describes the plugins available to the user for interacting with the webgme client / server.

UpdateGLDMeta Plugin

Location: ROOT

The UpdateGLDMeta plugin is useful for automatically updating or extending the webgme gridlabd meta language with information about the supported types from the current (or a selected) version of gridlabd. The plugin takes as input a type specification file (example) which can be automatically generated from gridlab-d in the following way:

gridlabd --modhelp ${module_name} > ${module_name}.cpp

e.g.

gridlabd --modhelp powerflow > powerflow.cpp

The information about gridlab-d's input arguments and how to run this command can be found here

When the UpdateGLDMeta plugin runs, it will check to see if the objects already exist, and if they don't it will create new meta-objects based on the file specification in a new MetaAspect sheet with the same name as the file. Additionally, if it finds a loaded svg (i.e. present in the ./src/svgs folder with the same name as the meta type it is trying to create, it will automatically assign that svg to be the icon for that type of object. In this way it is very easy to create a useful graphical modeling language for gridlab-d with a minimal amount of effort.

ImportGLM Plugin

Location: ROOT

From the root level, you can run the ImportGLM plugin which takes as input an uploaded GLM file. The plugin parses this file and creates webgme objects in accordance with the current webgme meta. This means that any relevant meta types for that model should be present in the meta.

The plugin supports auto-layout of the imported models. For the auto-layout code, the plugin takes input parameters specifying the number of iterations of the layout code, the length of the connections and the size of the objects to be laid out. For the most part, these parameters need not be changed from their default values. If the model is too densely packed, then increase the size / length parameters, and vice versa if the model is too sparsely packed. If the model is not laid out well (many crossing connections for instance), then increase the number of iterations.

GenerateGLM Plugin

Location: Model

The GenerateGLM plugin performs the reverse transform of the ImportGLM plugin, allowing the user to serialize their webgme gridlabd model out into a simulatable GLM file.

SimulateWithGridlabD Plugin

Location: Model

The SimulateWithGridlabD plugin provides the user the ability to automatically test their gridlabd model. It executes that model in GridlabD (which must be installed on the server) and provides the stdout / stderr back to the user for inspection.

SimulateTES Plugin

Location: Model

This plugin uses a a set of docker containers on the server to simuate a Transactive Energy System (TES) using CPSWT as the backbone for allowing distributed, coordinated simulation of reactive market controllers, reactive demand controllers, communications network, and power system.

Note: this plugin is designed to be run solely from the TwoCommunities model.

SimulateTESCluster Plugin

Location: Model

This plugin uses a cluster of VMs to simuate a Transactive Energy System (TES) using CPSWT as the backbone for allowing distributed, coordinated simulation of reactive market controllers, reactive demand controllers, communications network, and power system.

Note: this plugin is designed to be run solely from the TwoCommunities model.

Creating a Gridlab-D Model from Scratch

If the user does not wish to import or modify an existing power system model, they are free to create one from scratch by dragging a Model object from the part browser into the ROOT level of the project. Having done so, they can double-click to enter their new model. Once inside the model, they are free to again drag and drop any objects from the part browser into the active area of the model. Once created, these objects may be selected (upon which point their attributes will be displayed and editable within the attribute pane). The editable attributes for an object are derived from the META for that object, which was loaded as described in the UpdateGLDMeta section. A complete list of all possible attributes for all possible types of objects is outside the scope of this README, so users interested in which attributes have which physical meaning are referred to the Gridlab-D Wiki, where they can find the reference documentation for specific object types, e.g. for powerflow objects: Powerflow User Guide.

Note: Some capabilities of GLD currently only have limited support. The ability to define new object types on the fly within a GLM is not possible within the WebGME interface. However, the importer is able to parse, create, and serialize any such custom object types it finds. This feature may be supported in the future depending on users' needs and more discussion with GLD developers.