development of real life power system communication and ... - CiteSeerX

DEVELOPMENT OF REAL LIFE POWER SYSTEM COMMUNICATION AND PROTECTION LABORATORY AT VICTORIA UNIVERSITY Amanullah M.T.O, Md Mainuddin, H. Md Safayat, A.Kalam, A.Zayegh School of Electrical Engineering Victoria University of Technology PO Box 14428 MC, Melbourne 8001, Australia.

ABSTRACT This paper discusses about the development of a real life power system communication and protection laboratory at Victoria University. The purpose built real-life power system communication laboratory in a university environment will provide a unique learning opportunity to researchers, practicing engineers, students and faculty members to conduct experimental work and perform various real life power system researches. It will also operate as a training centre for utilities to train their staff prior to starting their work. This laboratory is the first of its kind in the whole Australia and will play pivotal role to train power system engineers. 1. INTRODUCTION Power supply is one of the most important resources to the human society development. The cost of power outage is on the order of millions of dollars. Power system can become vulnerable in the face of possible system abnormalities such as control, protection or communication system failures, disturbances and human operation errors . Therefore, to keep power supply stable and reliable is a very critical issue for future power system design. As the electric power industry enters the new century, powerful driving forces, uncertainties and new services are compelling electric utilities to make dramatic changes in the power system information infrastructure design. The increasing incorporation of digital devices throughout the enterprise as well as the forces of deregulation is driving utility communications into new realms [1]. With these changes and development, the future power system engineers must be well trained and knowledgeable with the current technological advancement in power system and its communication infrastructure. Therefore, the best place for electrical power engineers to get hand-on experience is while studying in their respective learning environment. Hence, power system facilities such as power system hardware, remote terminal units, power system communication and control center facilities should be available within the university learning environment.

Developing a power system environment in a university with all the related equipments is possible due to advancement of hardware and software technologies. Developing the real power system laboratory will also provide future researchers to carry out their research and provide consulting opportunities. Key elements of the facility include a real life, flexible power system network, signal conditioning hardware, data acquisition (DAQ) equipment and client/server industry standard computer networking technology. The PSCL allow students and users to get experience on the realistic operation and control of power systems and expose to modern supervisory control and data acquisition (SCADA) equipment and procedures as used by the power industry. This laboratory is an extension of the existing facilities which was discussed in [2]. 2. TECHNICAL DETAILS In order to form a power system network, three phase line, transformers, motors, loads, communication facilities and relays were interconnected through transmission lines. A programmable logic controller (PLC) was connected to this network to send signals and receive fault signals. In this project the PLC device is acting as a Remote Terminal Unit (RTU). This power system is monitored and controlled by the Energy Management System (EMS). The EMS also involves a supervisory control and data acquisition (SCADA) system. A SCADA system can send any request to PLC device to perform any task. The PLC device always sends unsolicited data to the SCADA systems for analysis. In this project, the education version of CitectSCADA software was used. CitectSCADA allows user to send any input to the PLC device. User can observe the response that coming from the power system network. To transfer analog data of the three phase line to the PLC device, we need some device that can convert it to digital. A digital transducer connected with

RS485 to RS232 converter via a serial port with PLC was performing the conversion task. According to the preliminary design of the PSCL one of our aims is to make a successful communication between a three phase utility grid and the VU generator. Current flow through the general three phase utility grid is 50Hz in Australia.

Synchronization with this three phase utility grid needs a lot of technical issues to be considered. Earthing arrangements, backup protection, power quality and stable current flow are some of the considerations that need to be taken on to account before synchronization. Frequency and voltage level matching

VU Generator/ Motor

3-Phase Supply

Signal Conditioning

Signal Conditioning Bus 1

Bus 2 SEL-2411 Three-Phase Transmission Line SEL-2407

Three-Phase Transmission Line

SCADA MASTER OR CONTROL CENTRE

Three-Phase Transmission Line

Bus 3

SEL-2411

SEL-2411

Signal Condioning Three Phase Rectifier Electronic DC Load SEL-3301

SEL-2407 SEL-3021

SEL-2032

SEL-3351

SEL-3021 WAN GATEWAY SEL-351S

SEL-311C

OTHER IEDs SEL-451, SEL-749M, SEL487B, SEL-387B, SEL-547, SEL-551C, SEL-300 G,

SEL-2515

Figure 1: Power system communication and protection laboratory setup are involved in installation. As this part is complicated, synchronization between three phase utility grid and VU generator session was omitted from this primary phase. The tentative laboratory setup is shown in Figure 1. The Schweitzer Engineering Laboratories, Inc. (SEL) hardware will be used as shown in the figure. 2.1 ENERGY MANAGEMENT SYSTEM The EMS emulator consists of a computer embedded SCADA system, RTUs, PLC devices and power system equipment. 2.2 REMOTE TERMINAL UNIT RTU device collects information from the field device as well as communicates with SCADA system. RTU devices are programmed such that it

can provide required instruction to the field device. On the other hand, PLC devices can be used in instead of RTU. A typical PLC device is depicted in Figure 2. In the initial development phase , the communication process between the CitectSCADA software is done with the use of PLC device. In setup process the data transfer rate should be matched between both devices. CitectSCADA allows user to change the data transfer rate so that it matches with the data transfer rate of the field devices (PLCs or RTUs). Proper addressing of the tag of the CitectSCADA project has to be considered for successful response. CitectSCADA have various built in driver to communicate with different types of PLC devices and RTUs.

There are some situations where devices can not be connected with the available driver of the SCADA software. This is the situation where distributed network protocol (DNP3) or International Electrotechnical Committee (IEC) IEC 61850 protocol will be used.

•

•

•

• • • •

Figure 2: Typical PLC device as a Remote Terminal Unit [3] 2.3 MASTER STATION The master station is high speed computer embedded with CitectSCADA software. This is the centre point of the laboratory setup. Master Station is connected with RTU and other computer. CitectSCADA allows user to input any command that will perform the expected task at the RTU and display the action on the graphic window. The primary function of SCADA is to collect information (data) and provide an interface to control specific equipment such as PLCs, RTUs etc. CietectSCADA had all the required powerful features and configuration tools to communicate with PLC device and other devices. A sample project was done in CitectSCADA during the project completion period that will help future students to understand about the following aspects of SCADA [5]: •

•

•

Control of PLC devices or RTU from MTU using clear, concise, resizable graphics pages (screens), Techniques to perform single or multiple tasks using graphical control buttons to the graphic pages, Sophisticated animations designing to display the operating status and performance of the PSCL,

•

•

The way to show the status of a process or the state of an alarm by displaying text messages and graphics. Configuring the CitectSCADA project in one language and displaying it in other language for overseas student, Specifying keyboard commands that operate universally (for all pages) or just for individual pages, The method to monitor, control, log, and display (in various formats) all alarms, Providing historical and real-time millisecond trending in graphical format, How to produce periodic and event-driven reports in Rich Text Format (RTF), The steps involved in monitoring product quality with Statistical Process Control (SPC) facilities, Developing a multi-layered security system that allows personnel access to the area or areas of the plant within their control, Exchanging plant-floor data with other applications for data analysis and post processing, or to control the power system.

Other features such as templates, Genies, wizards, RAD Graphics, and automatic color swapping made it easy to configure the CitectSCADA system. In this project the communication with another computer was essential to show the file sharing capability of CitectSCADA. Live values of the some of the devices were stored directly to MSExcel which is running on another computer. This process allows users to monitor and current live data of the equipment of the power system from the server computer through MTU. Everyone can use these values for other purpose. This communication was done with the help of Microsoft Windows 2000 Dynamic Data Exchange (DDE) opportunities. The Master Station will be deigned to serve as a platform from which students and users can perform various experiments in order to gain experience on the operation and control of power systems. The Master Station laboratory applications will enhance the students’ perception of electrical power systems and their performance by graphically modeling the active control elements of the power system on a color computer screen as seen in Figure 3.

Figure 3: Typical SCADA unit display [4] 3. CONCLUSION The complete setup of this laboratory will provide power engineering system problems up front (design, experimentation and analysis), promote student teamwork and put engineering in a real-life context. It is hoped that this laboratory will help break down the conventional “barriers” between power systems, DAQ and provide the students a clearer sense and more realistic picture of what the future holds for electrical power engineers. More specifically, it is desired that this laboratory setup will help students visualize power system phenomena in terms of the EMS equipment used by power system operators. The final completion of the PSCL will also provide future opportunities for researchers and can be used as a training center for utilities, faculty members, engineers and students. Upon successful implementation of this project, similar power system laboratory such as power system protection laboratory can be easily set up and implemented in other learning environments. REFERENCES [1] B. A. Oza and S. M. Brahma, “Development of Power System Protection Laboratory Through Senior Design Projects,” IEEE Transactions on Power Systems, vol. 20, no. 2, pp.532-537, May 2005. [2] M.T.O. Amanullah, A. Kalam and A. Zayegh, “Power system communication laboratory,” AUPEC 05, 25th - 28th September 2005, Hobart, Tasmania, Australia. [3]www.midsoutho.com/SS_Remote_PLC_Control _Systems.html [4]www.hydro-eci.com/images/produit/b_scada.jpg [5] Citect SCADA user manual, 2006