Phasor Measurement Unit

www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962

Volume-6, Issue-2, March-April 2016 International Journal of Engineering and Management Research Page Number: 221-224

Abhishek Gupta1, Smriti Jain2, Vishal Kumar Agrawal3, Sohail Ahamed4, Saksham Aggrawal5, Rishabh Kumar6 1Assistant Professor, Department of Electrical Engineering, Swami Keshvanand Institute of Technology Management & Gramothan, Jaipur, INDIA 2Reader, Department of Electrical Engineering, Swami Keshvanand Institute of Technology Management & Gramothan, Jaipur, INDIA 3,4,5,6Student (B.Tech. 4th year), Department of Electrical Engineering, Swami Keshvanand Institute of Technology Management & Gramothan, Jaipur, INDIA

ABSTRACT PMU function can be incorporated into a protective relay Phasor is an electrical complex value containing of or other device. PMU measurements are often taken at 30 magnitude root mean square value and phase angle in polar observations per second (compared to one every 4 seconds form represents instantaneous electrical sinusoidal waveform. using conventional technology). Time stamping Phasor Measurement Unit (PMU) is a device that is used to each measurement to a common time reference (provided collect and provide instantaneous phasors from desire places by very high precision clocks) allows synchrophasors from of applications, attached with an instantaneous time and date of measuring called time-stamped data. Estimated phasors different locations and utilities to be synchronized. When sometimes are called synchrophasor, defined as a phasor that data from multiple PMUs are combined together, the is estimated from samples using a standard time as the information provides a precise and comprehensive view of reference for a measurement, and has common phase the entire interconnection. Synchrophasors enable a relationship as remote sites, is a synchrophasor. Phasors are superior indication of grid stress, and are often used used consumed by many applications to enhance power system to trigger corrective actions to maintain reliability. stability and control, such as sequence impedance calculations for transmission lines and fault location for mixed lines. Moreover, using PMU readings from remote II. LITERATURE VIEW sites of a wide- area system, dynamic behavior of the system can be monitored. With this knowledge, when the system The research on PMU started in 1893 by Charles stability margin decreases, the monitoring software can Proteus Steinmetz. He presented a paper on simplified detect such bad sign. Hence this operation is named Wide- mathematical description of the waveforms of alternating Area Monitoring. current electricity. Steinmetz called his representation a phasor with the invention of PMU in 1988 by Dr. Arun G. Keywords— Phasor measurement unit (PMU), wide area Phadke and Dr. James S. Thorp at Virginia Tech, monitoring (WAM), Wide-Area Protection & Emergency Steinmetz’s technique of phasor calculation evolved into Control (WAPEC). the calculation of real time phasor measurements that are synchronized to an absolute time reference provided by the Global Positioning System. Early prototypes of the PMU I. INTRODUCTION were built at VirginiaTech, and Macrodyne built the first PMU in 1992. Phasor Measurement units - called The Bonneville Power Administration (BPA) is Synchrophasors - are precise grid measurements of the first utility to implement comprehensive adoption of electrical waves to determine the health of the electricity synchrophasors in its wide-area monitoring system. Today distribution system. there are several implementations underway. Phasor measurement units are considered one of The project operated by Virginia Tech and the University the most important measuring devices in the future of of Tennessee utilizes a network of approximately 80 low- power systems. A PMU can be a dedicated device, or the cost, high-precision Frequency Disturbance Recorders to 221 Copyright © 2016. Vandana Publications. All Rights Reserved. www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962 collect syncrophasor data from the U.S. power grid. The of applications. A 16x2 LCD are used in our New York Independent System Operator has installed 48 project for show the output value of current and PMUs throughout New York State, partly in response to a voltage. devastating 2003 blackout that originated in Ohio and • These supplies supply constant output voltage affected regions in both theUnited States and Canada. with respect to the variation in load or source In 2006, China's Wide Area Monitoring Systems input voltage. In our project micro-controller need (WAMS) for its 6 grids had 300 PMUs installed mainly at constant 5volt for operation which is provided by 500 kV and 330 kV substations and power plants. By 7805 voltage regulator. 2012, China plans to have PMUs at all 500kV substations C. PMU Overview and all powerplants of 300MW and above. Since 2002, Voltage and current are measured by potential China has built its own PMUs to its own national standard. transformer and current transformer. This sensed signals One type has higher sampling rates than typical and is used that pass to PIC series micro controller which has inbuilt in power plants to measure rotor angle of the generator, ADC convertor . for stamped time , MCU received it from reporting excitation voltage, excitation current, valve GPS receiver through Universal Synchronous position, and output of the power system stabilizer (PSS). Asynchronous Receiver Transmitter (USART), 1 time per All PMUs are connected via private network, and samples second after edge of 1PPS signals. are received within 40 ms on average. The North American Synchrophasor Initiative (NASPI), previously known as The Eastern Interconnect Phasor Project (EIPP), has over 120 connected phasor measurement units collecting data into a "Super Phasor Data Concentrator" system centered at Tennessee Valley Authority (TVA).

III. DESIGN

A. Input Signal Boundary Before our PMU system is designed, we specified input signal boundary referenced to the level 1 of [1] for our PMU capability as follow. Signal frequency: ± 5 Hz from 50 Hz. Signal magnitude: 10 % to 120 % of 220 VRMS. Phase angle: -180 to +180 degree. B. Important Component Parts • PIC16F73 28 pin Micro-controller, we selected this micro-controller from ATMEL company that can be programmed to carry out a vast range of task and they can be programmed for voltage, current measurement and send this signals to LCD. • Current transformers we selected this transformer from procon control company that can reduce high voltage currents to a much lower value and provide a convenient way of safely monitoring the actual electrical current flowing in circuit. In D. PMU Operation our project the current transformer is used to This section describes how PMU works. The measure the value of current. operation begins after rising edge of GPS time pulse or 1PPS signal • Potential transformer or voltage transformer

(procon control) gets used in electrical power system for stepping down the system voltage to a safe value. In our project the voltage transformer is used to convert 240 volt to 12 volt ac component and measure the value of voltage. • LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range 222 Copyright © 2016. Vandana Publications. All Rights Reserved. www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962

A Phasor Measurement Unit(PMU) may provide the basis for synchrophasor measurements, and may be helpful in determining the power system dynamic behavior. It measures the voltage and current of the power system(at a particular time) and has a capability to transmit the same to the central server for monitoring of the network , processing of the data and exercising control actions. The device can be improved further to measure other power system quantities like power and power factor, frequency measurement and about inductive load. The further improvement in PMU is needed because the cost of available PMU’s in market is very high so we reduce its cost.

V. FUTURE ENHACEMENT

• Real time frequency measurement and monitoring. • Real time monitoring of different parameters like phasor, power factor and frequency. • Wide area measurement and control through state estimation, in very wide area super grids, regional transmission networks, and local distribution grids. • Increase power quality by precise analysis and automated correction of sources of system degradation. • Phasor measurement technology and synchronized time stamping can be used for Security improvement through synchronized encryptions like trusted sensing base • Increase the reliability of the power grid by detecting faults early, allowing for isolation of operative system, and the prevention of power outages.

REFRENCES

[1] IEEE Standard for Synchrophasors for Power Systems, IEEE Std. C37.118-2005 (Revision of IEEE Std. 1344- E. CIRCUIT CAPABLITY 1995). A Phasor Measurement Unit (PMU) measures the [2] Phadke, A.G. (Virginia Polytechnic Institute and State voltage, phase angle and frequency of the power system(at University) "Synchronized phasor measurements-a a particular time) and has a capability to transmit the same historical overview",C35.118-1998 to the central server for monitoring of the network, [3] Chou, P. and C. Park. Energy-efficient platform processing of the data and exercising control actions. The designs for real-world wireless sensing applications. 2005: device can be improved further to measure other power IEEE Computer Society. system quantities like current, power and power factor. [4] Thus, a PMU Smay provide the basis for synchrophasor https://en.wikipedia.org/wiki/Phasor_measurement_unit measurements, and may be helpful in determining the (introduction of PMU, defination ) [accessed at 12 dec. power system dynamic behavior. 2015] [5] http://www.digikey.com/en/articles/techzonejan/low- IV. CONCLUSION cost-microcontroller-based-phasor-measurement-units- improve-smart-grid-reliability (study about the micro- controller) [accessed at 13 dec. 2015]

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