Debomita Ghosh

Communication Feasibility Analysis for Smart Grid With Phasor Measurement Units

The conventional power system is going through a paradigm change towards smart grid. Phasor measurement units (PMUs) have emerged as the edifice for information technology related to wide-area monitoring systems (WAMSs) for power system monitoring, information communication, and control purposes. The PMUs require communication links for a complex interconnected power grid, and proper spatial coordination plays a vital role for wireless communication network. Geographical information system (GIS) provides a rich set of functions to analyze the power network incorporating geospatial features. This paper investigates the impact of topological attributes on commissioning of wireless communication network for PMUs incorporating GIS aided analysis and to optimize one of the PMU location as main control station. This will not only serve for monitoring automation purposes, but will also ensure control automation. Case studies related to the eastern grid of India corroborate the efficacy of GIS-aided wireless communication for linking PMUs.

Reliability Analysis of Phasor Measurement Unit Using Hidden Markov Model

Recently, electrical power systems have emerged as the largest and most complex machine because of its inordinate growth due to technological innovations and because of geographical sprawl. This growth has necessitated a commensurate system for operation, monitoring, and control, which is known as the wide-area measurement system (WAMS). The edifice of WAMS is the phasor measurement unit (PMU). Its failure adversely affects WAMS as a whole; therefore, reliability analysis of the PMU is extremely essential. This paper uses hidden Markov model to perform the reliability analysis of PMU. Although many reliability evaluation methods have been used for computing steady-state probabilities, the proposed methodology has the unique ability to compute transient probability, leading to better system monitoring during transient states to ensure proper restorative initiatives. This paper validates the efficacy of the proposed methodology with relevant case studies for real-time application in a modern power system to ensure reliable monitoring using PMUs.

Simulation of wide area measurement system with optimal phasor measurement unit location

Traditional supervisory control and data acquisition (SCADA) measurements have been providing information regarding different power system parameters for decades. These measurements are typically taken once every 4 to 10 seconds offering a steady state view of the power system behaviour. However, for monitoring and control of large grid only steady state information may not be sufficient. Phasor measurement units (PMUs) provide dynamic view of the grid. Since PMUs are costly device, optimal placement of PMUs is a thrust areas of research in power system planning. This has been already investigated in previous research findings by different optimization technique. This paper extensively corroborates a simulation model of a wide area network with optimal PMU location. The purpose is to experimentally determine the ability of PMU to observe the entire network from its optimal location. The proposed methodology is implemented and investigated on IEEE six bus system using MATLAB/Simulink.

Performance simulation of phasor measurement unit for wide area measurement system

With the phenomenal growth of power system both in terms of geographical sprawl as well as technological advancements, it requires tools for dealing with system-wide disturbances that often cause widespread catastrophic blackouts in power system networks. When a major disturbance occurs, protection and control measures play the most important role to prevent further degradation of the system, restore the system back to a normal state, and minimize the impact of the disturbance. Continuous technological innovations in information and communication technology, novel sensors and measurement principles in general have promoted the advent of phasor measurement units (PMUs). This paper describes the modeling and testing of phasor measurement unit for two bus transmission line system using MATLAB/Simulink. Since PMUs are costly device therefore module wise testing and analysis are essential. For such modeling and testing, software based analysis is the best approach. This has been done through MATLAB and the results are analyzed.

A graph theory approach for reliability analysis of phasor measurement units using frequency and duration technique

Failure frequency and steady-state availability are two key indices for reliability analysis of phasor measurement units. Phasor measurement unit is the edifice of wide area measurement system and thus reliable operation is essential. Markov model is the general basis for evaluation of reliability indices, but it involves matrices of large dimension. This article describes the general purpose graphical approach for obtaining the two key reliability indices of phasor measurement units from flow graph based on Markov model. It is concerned with the calculation of availability, frequency and outage duration of phasor measurement units by module wise reliability analysis. This method itself is sufficient for sensitivity analysis of phasor measurement unit and helps in identifying the critical module within the phasor measurement unit.

Reliability analysis of a geographic information system-aided optimal phasor measurement unit location for smart grid operation

The conventional power system is going through a paradigm change towards smart grid, incorporating technological innovations for sensing, communicating, applying intelligence and exercising control through feedback. Recently, phasor measurement units (PMUs) have been used extensively for the purpose of sensing and communication. In many system planning studies, planners experience conflicts while taking into account the requirements related to communication systems, environment and geographic configurations owing to lack of proper spatial co-ordination. A geographic information system (GIS) provides a rich set of functions to view the power system network and to explore the geospatial relations. The main contribution of this article is to investigate the impact of topological attributes on commissioning phasor measurement units to ensure reliability through different phasor measurement unit connectivity configuration. Comparative studies have been done amongst different phasor measurement unit connectivity configuration for determining the most reliable data exchange methodology. Case studies related to the eastern grid of India corroborate the potential use of geographic information system taking pragmatic spatial aspects into account for phasor measurement unit placement.

Simulation of phasor measurement unit (PMU) in MATLAB

The advent of phasor measurement unit in power system is revolutionizing the conventional grid towards smart grid. Phasor measurement units are extremely expensive devices which takes into account many aspects of the power system that are not disclosed by the manufacturer while estimating phasors of currents and voltage. This paper aims to build a laboratory prototype of PMU which can estimate the phasor updating process of a commercial PMU at the benefit of improved measurement accuracy, reduced manufacturing cost and increased timely information.

Reliability analysis of PV cell, wind turbine and diesel generator by using Bayesian network

Due to environmental issues nowadays renewable energy sources are added to conventional power systems in the form of microgrid. Microgrids increase the energy efficiency and reliability of power supply. Due to the involvement of renewable energy resources in microgrid whose behavior is uncertain in nature due to environmental aspects the reliability assessment of microgrid is necessary. This paper proposes a novel methodology for evaluating the reliability of diesel generator (DG), photovoltaic (PV) cell and wind turbine by using Bayesian network. Bayesian network provides a flexible and adaptable way for representing uncertainty and mutual dependence of components. The system modeling is done by Bayesian network and system reliability is evaluated by using bucket elimination algorithm. Bucket elimination is a simple algorithm which reduces complexity of the calculations involved. Reliability index like diagnostic importance factor (DIF) is also computed from the posterior probabilities obtained from Bayesian network. Further critical component ranking of different components of DG, wind turbine and PV cell is also analyzed for efficacy of the results obtained.

Fuzzy approach for reliability analysis of PMU

The phenomenal increase of consumption of power in recent times has led to a paradigm shift of conventional power system towards smart grid. In particular phasor measurement units (PMU) have been instrumental for linking of sprawling network through wide-area measurement system (WAMS). Thus, the failure of PMU will lead to catastrophic outage and severe blackout in the power system. In this paper, the reliability modeling of PMU has been done using Markov process. Then, the reliability parameters (failure rate and repair rate) are calculated using symmetrical triangular membership function for type-1 fuzzy reliability analysis. The case studies corroborate the efficacy of type-1 fuzzy sets to take into account uncertainty related to membership function.

Adequacy analysis of stand alone hybrid microgrid by using Bayesian network

Nowadays microgrids have emerged as a popular option for satisfying the ever increasing energy demand. Microgrids are the combination of renewable energy sources with non renewable energy sources. The power supply from the microgrid must be adequate to satisfy the load demand. The adequacy analysis of microgrid is necessary because of the random behavior of renewable energy sources involved in case of microgrid. In this paper a new methodology based on Bayesian network is utilized for evaluating the adequacy indices of a stand - alone hybrid microgrid containing photovoltaic (PV) cell, wind turbine and diesel generator (DG). Here microgrid modeling is performed by Bayesian network and adequacy indices are computed by bucket elimination algorithm. Bayesian network provides a flexible and adaptable way for representing uncertainty and random behaviour of the units of microgrid. The severity ranking of different units of the hybrid microgrid is also performed based on posterior probabilities obtained from Bayesian network.