AIP Conference Proceedings 2233, 030009 (2020); https://doi.org/10.1063/5.0001584 2233, 030009

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Generic protective relaying framework forHV grid networkCite as: AIP Conference Proceedings 2233, 030009 (2020); https://doi.org/10.1063/5.0001584Published Online: 05 May 2020

Sultan Eissa Eissa Shwok, Chockalingam Aravind Vaithilingam, and Reynato Andal Gamboa

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Generic Protective Relaying Framework for HV Grid Network

Sultan Eissa Eissa Shwok1, Chockalingam Aravind Vaithilingam1,a), Reynato Andal Gamboa1

1School of Engineering, Taylor’s University, Taylor’s Lakeside Campus, No.1, Jalan Taylor’s, 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia

a)chockalingamaravind.vaithilingam@taylors.edu.my

Abstract. This article presents an alternative for the protective relaying framework for high voltage (HV) grid network specifically for the 33kV substation. The schematic drawings of the protective relaying panels of the 33kV substation were used to be created manually in AutoCAD software. In order to create the generic framework, a plugin in AutoCAD was developed to automate the generation of the schematic drawings of the protective relaying panels of the 33kV substation. The plugin was written in C# .NET programming language and developed using Microsoft Visual Studio which supports developing C# .NET applications. Development of the plugin were split into two stages, the first stage was developing the algorithm for back-end of the plugin, and the second stage was developing the graphical user interface (GUI) for the front-end of the plugin. Both the back-end and the front-end had to be integrated together in order to create a fully functional plugin. The plugin was tested to check if it could generate the schematic drawings automatically without the need to open them in AutoCAD.

INTRODUCTION

In electrical power systems, electricity is generated, transmitted, and distributed to the consumers by a high voltage grid (HV Grid). The HV grid is simply an interconnected network that consists of a generator to generate the electrical power needs to be supplied, transmission lines to carry the electrical power generated from the generator to the loads, and then a distribution system to distribute the power to consumers. The demand of power varies depending on the type of consumers whether they are domestic, commercial, or industrial consumers[1]. Every power system should be designed in a such way to be flexible for meeting the present demands as well as meeting increasing demands of the consumers that is expected to rise in the future due to the high growth in all areas of life. Delivering the electrical power to the consumers has to be secured from any power failure that can affect its operations. An electrical power system must keep the continuity of these operations without any sever breakdown [2]. Hence, it comes the importance for providing the maximum protection to these electrical power systems which plays a very significant role to ensure the high availability of the electrical power without interruptions whether it is a serious interruption or negligible [3].

Protective relaying devices are critical for power grids in order protect it from any type of faults. Electrical faults occur when there is an abnormality in the current passing through the electrical power system due to a short circuit or an open circuit occurred in that system [4]. The protective equipment used in the electrical power system protection is called switchgear. Switchgear consists mainly of two parts; protection components and control components. Protection components consists of protective relays, circuit breakers, fuses, isolators, and lighting arrestors as these components are responsible for isolating the faulty zone from the rest of the power system providing the full protection during fault conditions. Control components consist of control panels, current transformer (CT) and voltage transformer (VT) which are used to monitor the current and the voltage respectively in the system and step them down in case of abnormality occurs in the power system. Protective relays are basically used to send a signal received from the monitoring devices CTs or VTs to the circuit breakers in order to open the circuit to protect the entire system and isolate it from the faulted area [4]. These protective devices are placed in one place called substation.

13th International Engineering Research Conference (13th EURECA 2019)AIP Conf. Proc. 2233, 030009-1–030009-11; https://doi.org/10.1063/5.0001584

Published by AIP Publishing. 978-0-7354-1992-6/$30.00

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An electrical substation essentially consists of a number of incoming and outgoing power carriers that are connected to one or more common bus/busbar, which is a metallic conductor that collects the electrical power at one location [5], by circuit breakers, disconnectors, and instrument transformers. The electrical substations play an important role in the protection of electrical power systems as the protection equipment such as protective relays, current transformers (CTs), voltage transformers (VTs) are all installed together with the circuit breakers and disconnectors which can perform the switching operations [6]. The system grounding is also established in the electrical substations. Hence, it comes the important role of the protective relaying system in the electrical substations since these devices consist of all the major components parts of the electrical power system. However, these electrical substations require an extremely precise design process which provide all the schematic drawings of these substations in very detailed [7].

A complete drawing of schematic diagrams for the power system protection of a grid has to be designed correctly including the protection and control components alongside the other major components of the grid. Thus, designing a system of protective relaying devices is a very precise and complicated process as selecting the right device is very significant as each different electrical power system requires certain level of protection, and every single wire in the system must be connected exactly in the correct place.

At the present time, the design process of the protective relaying system is done through computer-aided design software such as AutoCAD. However, this design process is very time-consuming even though is done on computers. The process of designing a single protection panel for a protective relaying system, which contains all the protective relaying devises and the interconnections of these devices with other devices, may take several days up to weeks to be finished depending on how much the voltage level of that system as the higher the voltage level of the system the more complex its design becomes. Hence, the importance of solving this issue lies by finding an effective way for fixing this problem of time-wasting. The solution can be found by creating a framework that can generate the full design of the protection panel based on what the user would select of inputs for the system. Nonetheless, AutoCAD provides users with a very special feature as it allows them to customize tools that can automate the repetitive tasks which can greatly help reducing the time-wasting issue. Therefore, developing a customized tool in AutoCAD that can combine all the manual and time wasting design procedures could definitively solve this issue.

METHODOLOGY

Materials

To develop a plugin for AutoCAD, C# .NET is the programming language that is used to write the codes for the plugin. C# .NET is one of the languages that supports Microsoft .NET framework that can work with AutoCAD .NET Application Programming Interface (API), which allows to create customized tools for AutoCAD. The programming codes will be written in Visual Studio, which is a source-code software that is developed by Microsoft and can support developing .NET languages.

Understanding the Object Model of AutoCAD

AutoCAD has a hierarchical structure of how it works which elaborates the way that the document is created, which represents the sheets of the schematic drawings of the panels, and how it creates a block and access its attributes. By understanding this hierarchical structure, the algorithm needed for creating the plugin should follow the approach that will be used for developing the programming codes. Figure 1 shows the hierarchical structure of AutoCAD.

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FIGURE 1. Hierarchical structure of AutoCAD

FIGURE 2. Flowchart of the research methodology

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Developing the Algorithm for the Back-end of the Plugin

First: Accessing the Document

Based on the hierarchical structure of AutoCAD, the plugin should open AutoCAD application in order to implement changes on the schematic drawings. Then, the plugin should access the documents that contain the schematic drawings of the panel. Among all the documents, the plugin should identify a single document that is needed to be accessed. The format of the selected document should end with (.dwg) which is the AutoCAD format of the schematic drawings documents or files.

Second: Finding the Targeted Block

Once the document is accessed by the plugin is done, a couple of blocks are found inside the documents, which represents the components and the elements found in the schematic drawings of the panel. The plugin should then look for the block of the targeted component that needs to be accessed its attributes.

FIGURE 3. Set of blocks of a single schematic drawing document in AutoCAD

Third: Updating the Attributes of the Targeted Block

When the plugin detects the targeted block, it should open the editor that allows accessing the attributes of the block. The attributes are the data that is consisted for each element of the panels’ components. Then, the attributes can be updated based on the options that will be provided by the plugin. Figure 4 shows the list of attributes that pops up when a block is selected in the schematic drawing document.

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FIGURE 4. List of attributes of a single block of schematic drawing of a panel

Developing the Graphical User Interface for the Front-end of the Plugin

First: Creating the Main Window

The graphical user interface (GUI) represents the front-end for the back-end of the plugin. The front-end can be developed using Microsoft Visual Studio. It provides the necessary tools that helps build the graphical user interface of the plugin. It also has the ability to integrate the front-end with the back-end to build fully functional program. For the front-end of the plugin, a main window should be created to provide the user a list of options to choose what component needs to be updated

FIGURE 5. Developing the main window using Microsoft Visual Studio

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Second: Creating the Sub Windows

Each component will independent window from the other. The window will provide the user the list of changes that will be applied in the schematic drawings. The changes will be implemented in the database of the backend. Thus, the user will not need to apply a change in the schematic drawing manually as all the changes will be implemented automatically in multiple buttons to perform the work with only a single click.

FIGURE 6. Developing the sub windows using Microsoft Visual Studio

RESULTS AND DISCUSSION

Opening the Plugin inside AutoCAD

The plugin was installed in AutoCAD menu in order to open it quickly and save time for the user instead of opening it manually through AutoCAD commands which takes time and it is required to perform it every time the user opens AutoCAD. Figure 7 shows where the plugin was installed in AutoCAD menu under OpenDWG option, which is a list that was created to add the plugin inside. The name of the developed plugin is DWG Generator.

FIGURE 7. AutoCAD main interface shows the new dropdown menu created for the plugin

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Opening the Main Window

Once the plugin was opened from the dropdown menu, the main window popped up inside AutoCAD interface. Inside the main window, there were two dropdown menus created for two different voltage level of panels; one for 11 kV panels and the other one for 33kV panels. Under each dropdown menu, there are the types of panels that can be selected based on their purpose as for now there is only type of panel which is protection and control panels. Under the type of panel menu, there is the list of components that are chosen based on the requirements of the user. The list of components consists of two types of relay; overcurrent (O/C) and earth fault (E/F) protection relay, and other one is line differential protection relay. Under each type of protection relay, there are the list of manufacturers for each type. Each manufacturer has its own models. Thus, the users would have the variety of choices to select for their panels based on their requirement.

FIGURE 8. Main window of the plugin

Opening the Sub Window

The sub window is the window which contains the list of component elements that can selected and then generated after it is done. The component which can be selected are O/C and E/F protection relay and line differential protection relay. Each relay has different manufacturers, and each manufacture has different models of the same relay type. For instance, there two manufacturer for O/C and E/F protection relay; Siemens and Schneider Electric. Both have a component that performs the same function, but each one differs from the other one in terms of internal layout. The internal layout of each relay model consists of multiple ports each one serves a specific function depending on the requirements of the users. These ports are represented as block inside the AutoCAD schematic drawings of the panels. The ports have their own specifications which are represented as the attributes of the block. The specifications of the ports are interchangeable which means that whenever there is a change in the specifications, the user must look for the port where it is found in the schematic drawings sheets and update the attribute of block that represents the specification of the port that should be changed. Figure 9 shows the internal layout of Siemens Internal layout of Siemens O/C and E/F protection relay. The layout represents the function diagram of relay ports. Each port serves a function based on the user’s requirements. The functions are interchangeable among the ports. For instance, the function (CB Fail) can be found in a specific port in one panel, but it can be found in another port in the same type of panel due to the different requirement of the users. Thus, updating the schematics drawing should done manually.

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FIGURE 9. Internal layout of Siemens O/C and E/F protection relay

Hence, the sub window was created to automate the implementing the change of the ports for each function instead of doing manually. In the sub window, each function has multiple ports to choose for the schematic drawings. Once the user chooses one option for a specific function, the change will be implemented instantly without the need to open the file that contains the schematic drawing of that function. Figure 10 shows the sub window for the ports selection of the relay functions.

FIGURE 10. Internal layout of Siemens O/C and E/F protection relay

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Testing the Plugin

To test the plugin, certain functions were chosen, each function can be implemented to the ports that can be used for that function. For instance, the function (Trip Circuit Supervision) can be assigned to any of the four ports options found in Siemens relay as shown in Figure 9. The function requires two ports to be utilized in Siemens relay according to the requirements of the protection and control panel design. The ports are found in one of the schematic drawing sheet as shown in Figure 11.

FIGURE 11. The two ports dedicated for trip circuit supervision function

There are four options available for selecting the ports for this function as it can be seen in Figure 10 of the sub widow of the plugin. Instead of the old ports, when the new options were selected to update the ports, both options were implemented in the targeted schematic drawing sheet that contains the ports needed to be changed as shown in Figure 12.

FIGURE 12. The updated new two ports of trip circuit supervision function

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When the selection was done successfully, a message appeared in the AutoCAD command line showed that the ports of the function was updated successfully in the specified schematic drawing sheet as shown in Figure 13.

FIGURE 13. The message that shows the successful process of updating of the ports in the specified schematic drawing sheet

Comparison between the manual drawing and automated drawing

TABLE 1. Comparison of the time it takes to generate a schematic drawing manually and automatically Manual Drawing Automated Drawing

Single Sheet 2 minutes 4 seconds Single Panel 3 hours 2 minutes Entire Project 5 days 3 hour

As it can be observed from Table 1 above, there is a significant improvement when the generation for the schematic drawing of protection panels of 33kv was done automatically using the plugin over the manual way. That is because all the manual works had been converted into a plugin that can create all schematic drawings in a few clicks using the buttons in the graphical user interface (GUI) that are pre-programmed to perform all the processes of the manual design.

CONCLUSION

In conclusion, the AutoCAD plugin was developed to generate schematic drawings of high voltage substation particularly 33kV substation. The developing process was divided into two stages; first stage was on developing the algorithm for the back-end of the plugin while the second stage was on developing the graphical user interface for the front-end of the plugin. In the first stage of developing the plugin, the algorithm was derived based on the hierarchical structure of AutoCAD, which showed of how AutoCAD operates and processes. In the second stage of developing the plugin, the interface was created in such a way it could present all options in a single interface. Both the back-end and front-end were integrated to create the full functional plugin. The plugin was tested for automatic generating schematic drawings. The test was done based on the one of functions of a specific type of relay models, which is a main component of the protective relaying system, that was provided to be used for 33kV substation. The function chosen to test had multiple options of ports. The ports were provided in the plugin. Once an option of ports was selected, the plugin implemented the changes instantly in the schematic drawing sheet, where it contained the ports that needed to be updated, without the need to open the schematic drawing document in AutoCAD.

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ACKNOWLEDGMENTS

The project is supported through the Taylor’s Research Grant Scheme (TRGS) Project (TRGS/MF1/1/2017/SOE/007). The authors would like to express their sincere gratitude and appreciation to PSI Incontrol Sdn. Bhd for the technical support offered and providing what the project required of consultation and database.

REFERENCES

1. T. Gonen, Electrical Power Transmission System Engineering: Analysis and Design, Third Edition. CRC Press,2015.

2. S. Khan, Power System Protection. Shahriar Khan, 2013.3. R. P. Singh, Switchgear and Power System Protection. PHI Learning Pvt. Ltd., 2009.4. L. Hewitson, M. Brown, and R. Balakrishnan, Practical Power System Protection. Elsevier, 2004.5. Y. G. Paithankar and S. R. Bhide, Fundamentals of Power System Protection. PHI Learning Pvt. Ltd., 2011.6. “Electrical Bus-Bar and its Types,” Circuit Globe, 16-Jul-2016. [Online]. Available:

https://circuitglobe.com/electrical-bus-bar-and-its-types.html. [Accessed: 19-Jun-2019].7. P. Schavemaker and L. van der Sluis, Electrical Power System Essentials. John Wiley & Sons, 2017.

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