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THESIS WORK

General Overview

Prolan Inc. has been producing calibrating devices since years. After converting and expanding a three phase calibrating device, it was ready to be used as a protection-testing device as well. A control card inserted into an IBM compatible PC and the control software also belong to the system, which is called VAV System (Protection and Automatics Testing System). The parts of the control software are a programming language developed by Prolan, a compiler for this language, and an interface for handling the source files.

The programming language is optimized for testing protections and automatics. With writing and executing the programs (called testfiles) written in this language, any kind of examination can be completed. The results can be stored in report files, partial results can be displayed on the screen in text and in graphics (diagrams, tables etc.) format.

The topic of this thesis work is a program called VEDVIZSG (Protection examiner) created by the author. Before creating this program, the testfiles had to be written by hand. In case of the basic testfiles sold with the system it was an exercise of Prolan, and if the user needed more complicated testfiles, he could order them, or create them himself by learning the programming language.

The goal of creating VEDVIZSG (Protection examiner) is to make the testfile writing process easier in order to create the basic testfiles, and so that the user can also produce testfiles without learning the programming language.

VEDVIZSG (Protection examiner) works with a user-friendly interface. On this interface, the user can select the protection function (distance protections, overcurrent protections, etc.) to be tested from a menu. After this selection the parameters of the protection have to be set, the examination method, the parameters of the display, the contents of the report file can also be set up.

This thesis work summarizes the protection types, introduces the VAV system and the programming language in the first part. After then it introduces the VEDVIZSG (Protection examiner) program, the menus, the common dialog boxes for all protections, and the way the testfiles can be created.

Detailed information of Diploma Work

The background hardware and software tools for the investigations

The VAV System (Protection and Automatics Testing System) developed by PROLAN Inc. was used in this project (Figure 1). The parts of the VAV System: (explanations for the Hungarian text on the Figures)

• Control Software (VAV S3p);
• Control Unit (SCU3);
• Drive and Supplement Units by input/output.

The parts of Control Unit (Fig. 2):

• a normal PC;
• GPS module;
• SYNC (synchronous) module;
• A/D and D/A cards (6 analogue outputs, 16 anal. inputs).

The parts of Drive (VAV P3*10) and Supplement (VAV DIG 0) Units (Fig. 3):

The Supplement (VAV DIG 0) Unit:

• 3 voltage and 3 current outputs;
• 4 signal (digital) outputs;
• 8 signal (digital) inputs;
• switching matrix, to add current outputs into 1 phase.

The Drive (VAV P3*10) Unit:

• 3x2 channels, 3 voltage and 3 current outputs.

The Control Software (VAV S3p) has the next parameters and units:

The Program Language developed by PROLAN Inc. by the next possibilities:

• during the test the handling of display and notes of the events;
• handling of GPS and SYNC inputs;
• loading and displaying of files in Comtrade format;
• to communicate to the hardware and to prepare the test.

The system of TestFiles

For the actual examinations you need TestFiles written in this Prolan Program Language. In these TestFiles by the using of commands you can set the next parameters:

• to declare current and voltage output channels;
• to set the timing and the scaling of the signals;
• to control the handling and evaluation of the input signals.

• to edit and run the TestFiles.

• "no" short circuits on the voltage outputs;
• "yes" loads on the current outputs;
• "no" significant change in the load during the run.

• by the comparing of output and measured signals there is a real time control.

• To make the exact signal outputs and time measuring.

• for the next evaluation of the measured values.

The program "VEDVIZSG" (Protection examiner) developed in the frame of diploma project

The VEDVIZSG (Protection examiner) is a software to make the TestFiles. The run of TestFiles and the evaluation are in DOS therefor the VEDVIZSG operates in DOS, as well. A goal of diploma project was to create this software that will produce these TestFiles by automatic way for the VAV System.

The program VEDVIZSG supports the examination of the next protection types:

• overcurrent protections;
• distance protections;
• voltage protections;
• frequency decreasing protections;
• phase-to-ground short circuit protections;
• motor protections;
• generator protections;
• energy-flow direction protections.

How to prepare the TestFiles by the program VEDVIZSG (Protection examiner)?

• In a menu the user can select the type of the protection. The parameters needed for the examination can be set in dialog boxes.
• In the main (first) dialog box the user must set the next general parameters such as:
  • the name of the protection/examination;
  • the frequency of the examination;
  • the nominal current and voltage of the protection;
  • the maximum values of the test current and voltage;
  • the combination of the output signal valid for the starting of the protection;
  • the maximum value of delay until the starting.
• The user selects the function to be tested of the protection and the method of the examination;
• According to the selected method of the examination the user must set new parameters, for example:
  • how to change the currents and voltages (or the frequency) during the measuring;
  • what type of error will be generated by the system;
  • the user sets the return values of the currents and voltages after the starting of the protection, etc.
• In a new window the user sets the parameters of the displaying;
• In the other windows the user sets the notes on/off, the name of file and remarks for the next using of the TestFile.

After the set of parameters there are control windows and messages (file name, path, etc.). If the user changes and accepts the parameters then it will be the automatic generation of the TestFile. The user can read and change/write the created files. If a TestFile is ready the user of VEDVIZSG can use it or can create a new one.

The Fig. 5 shows the editor window and a part of a TestFile.

An example of the application.

The task of the test: the time - current characteristic of an overcurrent digital protection (made by Protecta Ltd., type DTI2-EP). In the test an R phase to ground short circuit was simulated.

The display of the results can be seen on Fig. 6.

E-mail: dpetri@freemail.hu  

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