Remote Access Of Substation To Automate And Protect Using Raspberry Pi

Remote Access Of Substation To Automate And Protect Using Raspberry Pi

ISSN: 2278-0181.

PECTEAM – 2K18 Conference Proceedings

1Suganya M J,2Gomathi B, 3Sivakami P, 4Rajarajeswari D, 5S.Balamurugan

1,2,3,4,5Panimalar Engineering College,

5RMK Engineering College

Abstract The objective of the project is to develop low cost solution for monitoring health condition of remotely located distribution transformers. The performance of prototype model developed is tested at laboratory for monitoring various parameters like transformer over load, voltage fluctuations, over temperature, oil quality and level etc. It continuously monitors the load conditions of the substation. It is designed to protect the electrical circuitry by operating an Electromagnetic Relay. This Relay gets activated whenever the electrical parameters exceed the predefined values. The Relay can be used to operate a Circuit Breaker to switch off the main electrical supply. The proposed project uses Raspberry pi as the heart of the project to control all the work involved.

Keywords Differential Protection, Raspberry Pi, differential relay

1. INTRODUCTION

   Electricity is an extremely handy and useful form of energy. A power system consists of components such as generators, lines, transformers, loads, switches and compensators. The main process of a transmission system is to transfer electric power from electric generators to customer area, whereas a distribution system provides an ultimate link between high voltage transmission systems and consumer services. In other words, the power is distributed to different customers from the distribution system through feeders, distributors and service mains. Supplying electricity to consumers necessitates power generation, transmission, and distribution. Power departs from the generator and enters into a transmission substation, where huge transformers convert the generator's voltage to extremely high voltages (155kV to 765 kV) for long-distance (up to about 300 miles) transmission. Then, the voltage level is reduced using transformers and power is transferred to customers through electric power distribution systems. Power starts from the transmission grid at distribution substations where the voltage is steppeddown (typically to less than 10kV) and carried by smaller distribution lines to supply commercial, residential, and industrial users. Electric utility substations are used in both the transmission and distribution system and operate independently to generate the electricity. The following discussion highlights on different capability limits of transformer 1.over load, 2. Over Temperature, 3. Over Excitation, 4 Oil Level Fault, This System will help us to identify problems before any fault occurs in transformer, resulting in a long life service for transformer. This system is based on Raspberry pi.

2. EXISTING SYSTEM

   Sub-station

   A substation is a part of an electrical generation, transmission and distribution system. The assembly of

   apparatus used to change some characteristics (e.g. voltage, frequency, p.f., A.C. to D.C. etc.) of an electrical supply is called a substation. Some of the main operations of substations are: To receive energy transmitted at high voltage from the generating stations.

   • To decrease the voltage to a value appropriate for local distribution.

   • To provide switching facilities.

   • Electric power may flow through several substations between generating plant and Maintaining the Integrity of the Specifications

   Electric power may flow through several substations between generating plant and consumer, and its voltage may change in several steps. Substations generally have switching, protection and control equipment, and transformers. In a large substation, circuit breakers are used to interrupt any short circuits or overload currents that may occur on the network. Smaller distribution stations may use recloser circuit breakers or fuses for protection of distribution circuits. Substations themselves do not usually have generators, although a power plant may have a substation nearby. Other devices such as capacitors and voltage regulators may also be located at a substation. in the network. Earth faults at a substation can cause a ground potential rise. Currents flowing in the Earth's surface during a fault can cause metal objects to have a significantly different voltage than the ground under a person's feet; this touch potential presents a hazard of electrocution.

3. PROPOSED SYSTEM

   Principle of Differential Protection scheme is one simple conceptual technique. The differential relay actually compares between primary current and secondary current of power transformer, if any unbalance found in between primary and secondary currents the relay will actuate and inter trip both the primary and secondary circuit breaker of the transformer. An automation system is proposed for the operators to monitor and control substation equipments with high mobility and security. A set of switches will be controlled by networking with the use of a Raspberry pi board. A Raspberry pi board obtains operator input from a operator friendly window that is accessed through a user name and password. The customized user friendly window has several buttons to control the equipments. A Raspberry pi will be located near field instruments and will be connected to all equipments in the substation with the help of electromagnetic relays. The Raspberry pi can be controlled from any remote place with the help of weaved cloud service. Webiopi framework gives us a platform to interact with Raspberry pi's General Purpose Input and Output pins. The Raspberry pi then either passes or stops current through an electromagnetic relay connected to the intended switch and this

   closes/opens the circuit allowing the equipment to run or get switched off. Thus globally accessible automation of substation equipments can be made possible with the use of a Raspberry Pi board, an internet connection and relay switches in a user friendly.

4. BLOCK DIAGRAM OF PROPOSED SYSTEM

   In this block diagram the transformer differential protection will be applied. This transformer current will be sensed by the two ends of the transformer. The sensor output will be given to the Raspberry Pi. The raspberry pi will be compile the current signal.

   Figure 1. single line diagram

   If it is any fault will be occurs the circuit breaker will be Trip. This system is capable of sensing internal and external faults

   In this system the transformers internal and external current will be sensed. The Raspberry Pi will be compile the current signal. If any fault occurs the Raspberry Pi will be pass the signal to the Micro controller. If controller get's the signal it will be trip the relay.

   Figure 2. Circuit Diagram Circuit Diagram Of Proposed System

5. HARDWARE COMPONENTS RASPBERRY PI The Raspberry Pi is a low cost, credit-

   card sized computer that plugs into a computer monitor or TV, and uses a standard keyboard and mouse. It is a capable little device that enables people of all ages to explore computing, and to learn how to program in languages like Scratch and Python. Its capable of doing everything youd expect a desktop computer to do, from browsing the internet and playing high-definition video, to making spreadsheets, word- processing, and playing games.

   Figure 3. Raspberry Pi Model B

   It also plays high-definition video. The design is based around a Broadcom BCM2835 SoC, which includes an ARM1176JZF-S 700 MHz prcessor, Video Core IV GPU, and 512 Megabytes of RAM. The design does not include a built-in hard disk or solid-state drive, instead relying on an SD card for booting and longterm storage. This board is intended.

   1. Input Voltage And Current At Fault Condition

      to run Linux kernel based operating systems. As typical of modern computers, generic USB keyboards and mice are compatible with the Raspberry Pi. The Raspberry Pi use Linux- kernel based operating systems. The Raspberry Pi does not come with a real-time clock, so an OS must use a network time server, or ask the user for time information at boot time to get access to time and date info for file time and date stamping. However a real time clock (such as the DS1307) with battery backup can be easily added via the I2C interface.

      Using Raspberry pi B model space CPU:

      • ARM 1176JZF-S 700MHZ

      • GPU: video core IV

      • RAM: 512 Megabytes

6. SIMULATION RESULT

   Figure 4. Simulation block

   Figure 5. Input Voltage And Current At Fault Condition

   Figure 6. Tripping Signal

   Figure 7. Output Voltage And Current At Fault Condition

7. CONCLUSION

Transformers being the essential part of power transmission system are expensive, as is the cost of power interruptions. Because of the cost of scheduled and unscheduled maintenance, especially at remote sites, the utility industry has begun investing in instrumentation and monitoring of transformer. This project is developed low cost solution for monitoring health condition of remotely located distribution transformers. The performance are monitored of prototype model developed is tested at laboratory for monitoring various parameters like transformer over load, voltage fluctuations, over temperature, oil quality and level etc. It continuously monitors the load conditions of the substation. It is designed to

protect the electrical circuitry by operating an Electromagnetic Relay. This Relay gets activated whenever the electrical parameters exceed the predefined values. We used Raspberry pi as the heart of the project to control all the work involved

FUTURE SCOPE

It is primarily utilized for data acquisition, in which sensor signals must be normalized and filtered to levels suitable for analog-to-digital conversion so they can be read by computerized devices. Other uses include preprocessing signals in order to reduce computing time, converting ranged data to Boolean values, for example when knowing when a sensor has reached certain values Types of devices that use signal conditioning include signal filters, instrument amplifiers, sample-andhold amplifiers, isolation amplifiers, signal isolators, multiplexers, bridge conditioners, analog-to-digital converters, digital-to-analog converters, frequency converters or translators, voltage converters or inverters and charge converters.

REFERENCE

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2. Shi, Di, Daniel J. Tylavsky, and Naim Logic, (2012), "An adaptive method for detection and correction of errors in PMU measurements." IEEE Transactions on Smart Grid 3.4: 1575-1583.

3. Meliopoulos, AP Sakis, et al, (2014), "Grid Modernization: Seamless Integration of Protection, Optimization and Control." System Sciences (HICSS), 2014 47th HawaiiInternational Conference on. IEEE.

4. Sevov, Lubomir, et al, (2014), "Differential protection for medium voltage pulse transformers." Petroleum and Chemical Industry Technical Conference (PCIC), 2014 IEEE. IEEE.