A Novel Supervisory Control for Residential Building Protection System

Transcription

1 A Novel Supervisory Control for Residential Building Protection System J. Rajaram, *N M Nor, T. Ibrahim, H. Daud, P. H. Shaikh * Electrical & Electronic Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Tronoh, Perak, Malaysia. nursyarizal_mnor@ petronas.com.my 1 Abstract Electrical power supply interruption due to some temporary faults has been a common problem in residential buildings. This leads to discontinuity of electrical supply to the building. However, power supply continuity is very important, as some of the appliances such as refrigerator, security, aquarium and fire alarm system requires continuous supply to be activated. Generally, when a fault occurs in the system, earth leakage circuit breaker (ELCB) will trip the circuit and ultimately disrupts power supply for all connected appliances. Therefore, manual power supply restoration has been performed in these buildings. In order to overcome the manual system restoration a novel automated system has been proposed. The paper aims to design and develop a supervisory control system employing local protection system employing Zigbee wireless technology. In addition to that a graphical user interface (GUI) based platform has been made to visualize and detect the faulty MCBs and isolate the fault via wireless Zigbee technology. Keywords Building, Fault, Zigbee, Protection, Automation I. INTRODUCTION ower failure is a common problem when electrical faults Poccur, which would lead to discontinuity of electrical supply in the residential buildings. Power supply continuity in these buildings is very important, since some of the appliances such as refrigerator, aquarium security and alarm systems require continuous electrical supply. When the fault occurs in the system, earth leakage circuit breaker (ELCB) will trip and disrupt the electrical supply to all the connected appliances. Faults may occur due to short circuit, ground fault or overloading. The aim of this project is to design and develop an automated system, for the single-phase residential building power system in order to overcome the problem discontinuous supply. The automated system is able to detect and isolate the fault in order to ensure the power continuity in the building via a supervisory control system with the Zigbee wireless technology. Since, it is has been designed which is very cost effective and could easily monitor the state of power supply continuity to the residential building. Wireless Zigbee has been used as communication link to integrate the graphical user interface (GUI) with automated ELCB and fault location detector which is automated electrical protection system (Auto-EPros). This system has been priory fabricated in a single system for better and effective usage of the supervisory control system. In this paper, we describe the novel Auto-EPros supervisory control system for monitoring and controlling through GUI platform along with Zigbee wireless communicating link. This system will locate the fault and isolate it from rest of the circuit ensuring continuity in building power supply. The remainder of the paper is organized as follows. Section II explains the working principle of ELCB, MCB and Graphical User Interface(GUI). Section III provides details on the system operation. Section IV describes the system design of a new supervisory control system via Auto-EPros system. Section V and VI analyzes the experimental and prototype test results and Section VII is provides details of entire prototype design of the control box. Section VIII wraps up the article. II. WORKING PRINCIPLE It is important to understand the main components which involves in the single phase protection system which are the ELCB for earth fault protection and MCB for over current and short circuit protection as both of these components are the core equipment which has to be controlled and monitor for the power flow in the Auto-EPros system. The Supervisory control system needs to be integrated with the Auto-EPros system, which uses zigbee protocols to communicate between the SKXbee modules connected to the laptop via GUI. Another Xbee module designed together with the control box, which will be controlling the Auto-EPros system. All the events of fault will be monitored via graphical user interface and control the Auto-EPros system. A. Earth Leakage Breaker (ELCB) An ELCB is operated when there is flow of current to ground from wiring system and disconnects the power supply [8]. There are two types of ELCB. A voltage ELCB comprises of sensing coil and detects sufficient voltage across the coil. It gets disconnected, when the power supply and will remain in off condition if it does not manually turn-on back by the consumer. Whereas, the current ELCB is operated as the current passes through the sensing coil and if any unbalance occurs in electrical current, then it is tripped /14/$ IEEE 286

2 B. Miniature Circuit Breaker(MCB) The main purpose of an MCB is to protect electrical equipments against overload (thermal) and short circuit (electromagnetic). Hence, it drives the meaning of protecting electrical equipments from excessive temperature and current [4]. The MCBs are mainly used in distribution system is designed without the use of fusible element isolating a circuit during an overcurrent incident [4]. C. Graphical User Inerface In order to transmit data from a centralized position to the end use devices there must be an interface which could communicate with the devices and the ultimate users. The user had to be trained well to be able to operate the system, which requires the skills for decoding various information and the outputs from the user device. In order to make this process in a simple human machine interface (HMI) should be designed in a way, as it must be user friendly to transmit required information to the hardware setup [5]. However, using GUI will be easier for users to control and transmit data without any complexity. This provides best solution to interface computers and humans. The system design is simple which only requires input either from a keyboard to work on graphical view of the task required to be performed. As for example in SCADA system the power system network is interpreted in graphical view and operators just isolate a breaker by an input from the mouse, as it transmits command via fiber optics or wireless system. GUI could be developed in various kinds of software platforms such as visual basic, labview and matlab. D. Zigbee Wireless Network Zigbee is a very simple technology as it could communicate in 2 way directions, one as the data transmitting part and another one as data receiver part. This technology is being utilize globally for the purpose of building control, data acquisition, monitoring system and automation for manufacturing [6]. The main idea beyond this technology is a system which could compromise with low data rate wireless network technology and low power consumption [1]. Wireless technology has rapidly grown for various purposes and especially for controlling and monitoring system. These have replaced the systems, which uses complex wiring systems, which eventually deteriorate as its aging and might cause many defects, which could cause short circuit and damages a system. Wireless system technologies offer easier transmission and receive data in a very fast rate without complexity. This could lead to more reliable and efficient way to control and monitor a particular system. Besides, it is also very cost effective in term of installation and maintenance compared to wired system. In the current market there are various kind of wireless technology which are available as for example infrared (IR), Bluetooth, Radio frequency, Zigbee, Z-wave and Insteon. From all the available wireless technology zigbee has been an very effective solution for controlling and monitoring of a system, as it is a very low cost, low power and low rate wireless network standard which could be implemented for supervisory control systems in houses, factories and offices [1]. Zigbee is used mostly for a short distance wireless monitoring and control purpose [2]. It has been developed based on Open system Interconnection (OSI) layer model [3]. Its standard has been build on the IEEE low rate wireless personal area networks (WPAN) standard based which constitutes the physical layer (PHY) and Medium Access Control (MAC) layers as shown on Fig. 1 and it combines with zigbee alliance which includes network layer and application layers [2]. The physical layer has been designed to operate at two-frequency ranges in Europe 866 MHz, 915 MHz and in global frequency of 2.4 GHz [3]. E. Comparison between wireless technology It is vital to understand the main differences between a zigbee, Bluetooth as well as wifi, which all three of these technologies uses wireless protocols to communicate. Basically all this devices has the same design characteristic as defined in IEEE The only similarities on the physical layers (PHY) as well as the media access control (MAC) layers according to and on the network layer. However, the application layer differs because of different alliance companies work to develop a certain specification. This could lead them to commercialize their very own technology [3]. Even though it has very common similarities that it totally differs in term of simplicity of design and network configuration as well as data flow rate. Table 1 illustrates the difference between zigbee, wifi and Bluetooth technologies. TABLE 1 DIFFERENCE BETWEEN WIRELESS TECHNOLOGIES III. SYSTEM OPERATION The automatic system is designed for domestic electrical system to auto-reset ELCB and auto-detection if any permanent faults occurred at a load connected to a particular MCB and isolate the MCB from the power system. The new supervisory and control system is to isolate the particular fault 287

3 load connected to the isolated MCB and recover power back to the other load which is also connected to the particular MCB. The system operation is divided into three parts: power recovery, fault location detection and fault location isolation. In Power Recovery part, it covers about the automatic reset of ELCB, which restore the supply, the Fault Location Detection part will covers on how the permanent fault is being detected and the fault will be isolated from the main system. Once the fault location is identified, the detected MCB will be automatically isolated from the power system and the ELCB will be reclosed to restore the power supply. This will cover in the last part, the Fault Location Isolation. IV. SYSTEM DESIGN A. System involved There are three major systems in this project, as follow: 1. Auto-EPros Auto-EPros has been developed to detect the faulted MCB in domestic power system, and able to isolate the particular MCB from the system and recover the power supply by automatically reclose the ELCB. The prototype of Auto-EPros is shown in Fig. 1. Fig. 1: Auto-EPros System 2. Control Box or Control System The Control Box has been designed with a PIC microcontroller to enable it to detect all the fault events in power system via Auto-EPros system. This will send the signals via Zigbee to the GUI for the user to identify the faulted MCB visually, as shown in Fig. 2. User could isolate the particular faulted appliance connected to the faulty MCB which has been isolated by Auto-EPros, and are able to recover the power supply in the particular MCB. 3. GUI or Control Monitoring System The Monitoring system has been designed with Microsoft visual studio and was programmed to establish connection with SXBEE pro via serial com port as shown in Fig. 3. With this GUI system, the SXBEE pro connected to the laptop and the Xbee pro Module in the control box, which are able to act as transceiver to monitor the entire event in the power system via Auto-EPros, and controls the Auto-EPros system. Both this monitoring and controlling are performed via zigbee wireless technology. Fig. 3: Graphical User Interface B. Merging the control box and Auto-EPros System Fig. 4 illustrates the integration of the control box with the Auto-EPros system controlled through arduino board. When a permanent earth fault occurs, the ELCB will reclose for minimum three times to make sure it has been a permanent earth fault with the help of Auto-EPros. After that, it will relocate the faulted MCB with the current sensor through measurement of current difference. Once the faulted MCB has been detected by the arduino board, the power flow for the affected MCB will be disconnected with solid state relays. Then, the ELCB will be reclosed to restore the supply. The control box basically could monitor all the events via wireless and could detect the tripped condition of the faulted MCB. When the arduino output to solid-state relay are 0V and the same output is also connected to a relay in order to detect the tripping signal, when it goes to normally open condition. The signal is interpreted in the PIC microcontroller and sent through the XBee module via wireless to the monitoring system. From the monitoring system user is able to isolate the faulted appliance specifically through try and error process and connects back the isolated MCB to recover power flow. Fig. 2: Control Box Fig. 4: Merging Control box and Auto-EPros 288

4 V. EXPERIMENTAL TEST AND ANALYSIS The condition of ELCB and MCB used in this project has been tested by the control box. The conditions have been tested by observing the tripping condition of MCB 1, MCB 2, ELCB. A. ELCB and MCBs stable condition The Fig. 5 shows when the power flow in all of the three breakers is stable without any fault. This has been identified with indication of green LEDs. D. ELCB and MCB : Tripped condition Fig. 8 shows the results when the ELCB and both of the MCBs are tripped using GUI via wireless in the control box. From GUI, we can see that all three went on red indication and the LEDs in test bed are turned off which indicate that the fault is occurred. Fig. 8: ELCB and MCB S Tripped Condition Fig. 5: ELCB and MCB S Stable Condition B. MCB 1 tripped condition The Fig. 6 shows, when MCB 1 has been tripped after external fault is purposely created. The first box in GUI is turn to the red color indicate that MCB 1 is tripped. This signal is sent via wireless Zigbee. VI. PROTOTYPE TEST VIA GUI TO ISOLATE THE FAULT LOCATION Two loads represent by Blue LED and Red LED is connected to relays, which represents solid-state relays in the actual power system. These relays are connected to another relay representing MCB in the actual power system. All these relays are controlled by the control box via wireless Zigbee with GUI. This system illustrates the concept of controlling the Auto-EPros system. A. Power Flow in stable condition Fig. 9 shows the results when the power flow is stable without any fault condition as the both blue and red LED is turn on which indicates that it is operating well without any power outage from the power system. Fig. 6:MCB1 Tripped Condition C. MCB 2 tripped condition The Fig. 7 shows the results when two MCBs 1 and 2 has been tripped as indicated in GUI via wireless in the control box. Whereas, the LEDs also turned off indicating the fault has occurred. Fig. 9: Power flow in stable condition B. Fault Condition at MCB 1 Fig. 10 shown that the LED for both loads is turn off when fault occurs in MCB 1. This indicate that there is no power flow during the fault at MCB 1 and the load s connected to it will be tripped. 289

5 ACKNOWLEDGMENT Authors would like to acknowledge Universiti Teknologi PETRONAS for providing the facilities and financial support with awarded I-GEN fund to carry out the research work. REFERENCES Fig. 10: Fault Condition at MCB 1 MCB1 LOAD 1 and LOAD 2 C. Power flow at MCB 1 Recovered Fig. 11 shows that when faulty load has been isolated and MCB 1 is reconnect via GUI, the power flow has been recovered and one load connected to the MCB 1 will be reconnected to the supply. [1] Jun, Zhang Guangming, Song Hui, Wang Tianhua, Design of a Wireless Sensor Network Based Monitoring System for Home Automation, Future Computer Sciences and Application (ICFCSA), International Conference,2011,pp [2] Sarijari, M. A. B. Rashid, R. A. Rahim, M. R. A. Mahalin, N. H, Wireless Home Security and Automation System Utilizing ZigBee based Multi-hop Communication,Telecommunication Technologies 2008 and nd Malaysia Conference on Photonics. NCTT-MCP th National Conference on, August. 2008, pp [3] Zucatto, F. L. Biscassi, C. A. Monsignore, F. Fidelix, F. Coutinho, S. Rocha, M. L. ZigBee for building control wireless sensor networks, Microwave and Optoelectronics Conference, IMOC SBMO/IEEE MTT-S International, October 2007, pp [4] Edvard, Purpose of Miniature Circuit Breakers (MCBs) Energy and Power Low Voltage Protection, Retrieved from [20 November 2013] [5] Lavergne,M, Graphical user interface for next generation power systems,telecommunications Energy Conference, INTELEC. Twenty-second International, 2000, pp VII. FAULT LOAD ISOLATED COMPLTE PROTOTYPE OF THE CONTROL BOX Fig. 12: Power Flow at MCB1 Recovered [6] Ondrej, S. Zdenek, B. Petr, F. Ondrej, H, ZigBee Technology and Device Design, International Conference on Mobile Communications and Learning Technologies, April 2006, pp.129. [7] Palanisamy, S. Kumar, S. S. Narayanan, J. L. Secured wireless communication for industrial automation and control,electronics Computer Technology (ICECT), rd International Conference on, April 2011,pp [8] Jiguparmar, Working Principle of Earth Leakage Circuit Breaker (ELCB) and Residual Current Device (RCD), Energy and Power, Retrieved from [7 November 2011] VIII. CONCLUSIONS The test bed of Auto-EPros system and graphical user interface has been successfully integrated with wireless Zigbee. It can be seen that the proposed GUI-based platform is easy to monitor and control by the users. In addition, the supervisory control system able to identify the fault location and isolates the faulty MCB via wireless Zigbee to ensure the continuous of power supply. This novel supervisory control system provides new directions in the field of electrical protection system in buildings. The proposed system is significant in technical and economic aspects besides, commercially valued. In future, the project will be implemented in real building at large scale for its further validity. 290