Online database of Power Hardware In-the-Loop tests

The online database presented in this article provides information about Power Hardware In-the-Loop (PHIL) tests to allow the reproducibility of the experiments. The data were collected through published papers and manufacturer data sheets. The database is hosted on an open subversion platform, which allows a continuous improvement of the data. Furthermore, a GUI interface has been developed to ensure the integrity of the database and its traceability. The access to PHIL test data will facilitate reliable findings for the reproducibility of PHIL experiments.


Data
Power Hardware In-the-Loop (PHIL) is a test system technique which combines the system simulation flexibility with the fidelity of complete hardware test. It is based on a Digital Real-Time Simulation (DRTS) that communicates with a Power Amplifier (PA), which exchanges real power with the Hardware-Under-Test (HUT). This data article describes a database which contains information about PHIL tests, organized in eight different interconnected dynamic tables. The Unified Modeling Language (UML) representation of these dynamic tables is shown in Fig. 1. The variables contained in every table and their description are shown in Tables 1e8.
The database is implemented in Microsoft Access [2]. This software provides the possibility of dynamic classification of all available parameters of Power Hardware In-the-Loop (PHIL) tests, allowing the organization of the information without requiring programming skills. Furthermore, a user management system (Fig. 4) and a GUI interface (Figs. 5e7) are included to add, modify and update the online database. It also offers the possibility of showing information as a table or as a form, and users can copy and paste data to other database software to process them.

Experimental design, materials, and methods
A significant number of PHIL test reports have been collected from the scientific literature. The main data were extracted from these publications for reproducibility purposes. Some representative examples of these publications gathered in the database are [3e8]. The information of PHIL systems used in the tests was completed by extracting data from manufacturer datasheets and from PHIL review articles [9e16]. Publications with insufficient information were excluded.
Summary statistics of one of the most important variables included in the database are presented in Figs. 2 and 3. If any paper describes two or more tests, in which the same HUT type has been test or the same system has been simulated [7,8], it only counts once.
Specifications Table   Subject Electrical  [1], where the scientific community has the potential to improve and update the data, giving a complete perspective of the current developed PHIL tests to date. It is expected that this online database will be a useful tool which helps and boosts the improvement of the smart grid and the rapid prototyping of new systems.   In order to increase the comprehension and traceability of the items in the database, some noncategorizable fields have been added. A field called "Notes" has been added in every table, with the purpose of adding some extra information which is interesting for the readers. Furthermore, a web link of the item has been added in Tables 5e8. Moreover, the "Paper" table (Table 6) includes a "Summary", "Why and what for", "Results" and "Conclusions" to add the subjective information of the paper. The table "Power Amplifier" (Table 7) includes a field "attachment" where the datasheet of the system can be added.
Several methods have been considered in order to ensure information integrity, to increase readability, and to update the information periodically. These methods are described in the following subsections:

User management
The database allows modification after its publication. A user management system has been implemented to prevent anonymous database editing. The registration is done via email, with every  user having a unique username and password to enter the application. Only registered users are able to add new information to the database. Furthermore, only users with special rights can modify the information. Consequently, the database records the date and authorship of every addition/modification. Finally, a "guest" user allows non-registered users to read the database. Fig. 4 shows the login window to enter to the online database. Fig. 5 shows the database GUI. It has three main groups: check, add and modify information. Each group allows users to check, add or modify the reports, Power Amplifiers (PA), Digital Real-Time Simulator (DRTS), Companies/Universities and Hardware-Under-Test (HUT) device tables respectively. All users can access the items in the check information group. However, to enter the other two groups it is necessary to be registered in the database. Fig. 6 shows the PHIL tests report table which holds all the information included in the reviewed publications and it is accessed by the "Table Reports" button in the database GUI (Fig. 5). Fig. 7 shows the "form" to change PA data, which is opened by clicking the "Modify Power Amplifier" button in the database GUI (Fig. 5).

Database host
The database is uploaded to GitHub [1], which is an open-source version control system. It gives the possibility of changing and updating the database in an orderly manner, preventing the database from becoming outdated. However, since the Access database must be updated in GitHub as a binary file, only the main branch of the database could be useful to users. This form of centralised management enables better organised control of the database updating process. Consequently, this supervision technique will provide a third-party revision to prevent mistakes and any attempts of cheating.     6. "Table Reports" in the database GUI (Fig. 5), which contains the PHIL test manuscripts information of the database.