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Real time synchronized phasor measurement in power network is obtained by the improvement in monitoring, control and, protection of the power system. In recent time, the installation ratio of Phasor Measurement Units (PMUs) is constantly increasing for the real time measurement throughout worldwide. The increment in the number of PMU installation i...
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... optimization algorithms are compared with their performances in Table 1. The characteristics of these techniques are varied according to their nature. ...Citations
... Active management is needed in the power system that estimates the current state of in the electrical network, this measurement level is not good enough to monitor the varying effects in the system. The lack of monitoring, controlling, and protecting performance in the previous devices was noticed, therefore a novel device was introduced with Global Positioning Systems (GPS) and digital signal processing (DSP) in the late 1980s in the research laboratory of the University of Virginia [3]. In the latest survey according to North America Synchrophasor Initiative (NASPI), there are nearly 2000 PMU devices installed in the North American transmission and distribution network [4]. ...
... The real-time synchronized measurement is obtained by the improvement in monitoring, protection, and control of the power system [3]. Similarly, PMU provides the real-time synchronized measurement, synchronized frequency, rate of change of frequency of voltage, current phasor quantities, and their magnitude with a high precision rate of ±1 • or ±1% [2][3][4][5][6][7][8] with the support of GPS [14,15]. ...
... The real-time synchronized measurement is obtained by the improvement in monitoring, protection, and control of the power system [3]. Similarly, PMU provides the real-time synchronized measurement, synchronized frequency, rate of change of frequency of voltage, current phasor quantities, and their magnitude with a high precision rate of ±1 • or ±1% [2][3][4][5][6][7][8] with the support of GPS [14,15]. The measurement level of PMUs is very high -nearly 60 samples of measurement per cycle as compared to the traditional devices [16]. ...
The electrical network is a man-made complex network that makes it difficult to monitor and control the power system with traditional monitoring devices. Traditional devices have some limitations in real-time synchronization monitoring which leads to unwanted behavior and causes new challenges in the operation and control of the power systems. A Phasor measurement unit (PMU) is an advanced metering device that provides an accurate real-time and synchronized measurement of the voltage and current waveforms of the buses in which the PMU devices are directly connected in the grid station. The device is connected to the busbars of the power grid in the electrical distribution and transmission systems and provides time-synchronized measurement with the help of the Global Positioning System (GPS). However, the implementation and maintenance cost of the device is not bearable for the electrical utilities. Therefore, in recent work, many optimization approaches have been developed to overcome optimal placement of PMU problems to reduce the overall cost by providing complete electrical network observability with a minimal number of PMUs. This research paper reviews the importance of PMU for the modern electrical power system, the architecture of PMU, the differences between PMU, micro-PMU, SCADA, and smart grid (SG) relation with PMU, the sinusoidal waveform, and its phasor representation, and finally a list of PMU applications. The applications of PMU are widely involved in the operation of power systems ranging from power system control and monitor, distribution grid control, load shedding control and analyses, and state estimation which shows the importance of PMU for the modern world.
... PMU is a monitoring device to measure voltage/current magnitude, voltage/current angle, and frequency [9]. From PMU, universal synchronized data [10] are found, which are analyzed to increase the reliable transmission and distribution side [11]. At a time, PMUs can deal with magnitude and phasors, which is why they are also named synchro-phasor device [9]. ...
The application of the Phasor Measurement Unit (PMU) in the power system is expanding day by day since it provides a higher reliability through fast symmetrically monitoring and protection and assists in controlling power systems. For power systems, islanding is a significant event due to its hazardous consequences. To detect islanding events, several schemes have been previously proposed but inappropriate threshold setting, higher computational time, and false tripping are the main limitations. In addition, differentiating between real island events and transient faults is another limitation. However, appropriate threshold setting plays a considerable part in detecting the island event, which is also important to differentiate between real and non-island events. Phasor Measurement Unit can assist in islanding detection, but it can generate 30 samples/s, so there is always the possibility of making particular period data disappear. The principal contribution of this review article is its detailed discussion of real-time symmetrical PMU data and it further presents different PMU data analytic techniques and the proposed schemes for the islanding detection system. An appropriate methodology tried to understand how to incorporate missing PMU data techniques along with the islanding detection system to ensure the higher reliability of the network.
... Although measurements are scanned through out the system, the system's state is presumed to be static.Whereas power systems are operated completely dynamic in nature. High price tags of PMUs forced the researchers to investigate the optimal locations for the complete observability of the electric network [20]- [27]. ...
Sustained growth in the demand with unprecedented investments in the transmission infrastructure resulted in narrow operational margins for power system operators across the globe. As a result, power networks are operating near to stability limits. This has demanded the electrical utilities to explore new avenues for control and protection of wide area systems. Present supervisory control and data acquisition/energy management systems (SCADA/EMS) can only facilitate steady state model of the network, whereas synchrophasor measurements with GPS time stamp from wide area can provide dynamic view of power grid that enables supervision, and protection of power network and allow the operator to take necessary control/remedial measures in the new regime of grid operations. Construction of phasor measurement unit (PMU) that provide synchrophasors for the assessment of system state is widely accepted as an essential component for the successful execution of wide area monitoring system (WAMS) applications. Commercial PMUs comes with many constraints such as cost, proprietary hardware designs and software. All these constraints have limited the deployment of PMUs at high voltage transmission systems alone. This paper addresses the issues by developing a cost-effective PMU with open-source hardware, which can be easily modified as per the requirements of the applications. The proposed device is tested with IEEE standards. © 2021 Institute of Advanced Engineering and Science. All rights reserved.
... A PMU is a metering device that has the ability to directly measure the voltage phasor of the installed bus and the current phasors of all the lines connected to that PMU installed bus. A large number of PMUs are now being installed in developed countries to monitor, protect, and control the electrical system as a whole [2]. ...
... The proposed technique locates the f-bus and t-bus in the branch data, and these are mainly useful in constructing the structure of adjacent matrix B regarding the OPP problem in which the linkage between the buses is known by the current incident branch lines, which start at the f-bus and end at the t-bus. The example of a proposed matrix B in the OPP problem concept is intended to be a power system observability, as given below in Equation (2). ...
Recent developments in electrical power systems are concerned not only with static power flow control but also with their control during dynamic processes. Smart Grids came into being when it was noticed that the traditional electrical power system structure was lacking in reliability, power flow control, and consistency in the monitoring of phasor quantities. The Phasor Measurement Unit (PMU) is one of the main critical factors for Smart Grid (SG) operation. It has the ability to provide real-time synchronized measurement of phasor quantities with the help of a Global Positioning System (GPS). However, when considering the installation costs of a PMU device, it is far too expensive to equip on every busbar in all grid stations. Therefore, this paper proposes a new approach for the Optimum Placement of the PMU problem (OPP problem) to minimize the installed number of PMUs and maximize the measurement redundancy of the network. Exclusion of the unwanted nodes technique is used in the proposed approach, in which only the most desirable buses consisting of generator bus and load bus are selected, without considering Pure Transit Nodes (PTNs) in the optimum PMU placement sets. The focal point of the proposed work considers, most importantly, the case factor of the exclusion technique of PTNs from the optimum PMU locations, as prior approaches concerning almost every algorithm have taken PTNs as their optimal PMU placement sets. Furthermore, other case factors of the proposed approach, namely, PMU channel limits, radial bus, and single PMU outage, are also considered for the OPP problem. The proposed work is tested on standard Institute of Electrical and Electronics Engineering (IEEE)-case studies from MATPOWER on the MATLAB software. To show the success of the proposed work, the outputs are compared with the existing techniques.
... This leads to insecure and unstable operation of the power system [1]. Therefore, a wide area monitoring scheme is extremely important to monitor the whole power system operation and make a proper preparation for possible system stability issues [2][3][4][5][6][7]. Phasor measurement unit (PMU) is installed for this monitoring purposes. ...
... More explaination on determining optimal PMU placement is given based on a five bus system as illustrated in Figure 1. The binary connectivity matrix, A can be obtained from branch data of the network as expressed in (4). Alternatively, it can be directly constructed from the admittance matrix in which all non-zero elements are assumed 1s and 0s. ...
This paper presents an alternative approach to solve an optimal phasor measurement unit (PMU) placement by introducing two new sensitivity indices. The indices are constructed from the information measured from PMUs such as voltage magnitude and angle. These two parameters are essential for power system stability assessment and control. Therefore, fault analysis is carried out to obtain the voltage magnitude and angle deviations at all buses in order to construct the indices. An exhaustive search method is used to solve the linear integer programming problem where all possible combinations of PMU placement are evaluated to obtain the optimal solution. Unfortunately, the traditional objective function to minimize the total number of PMU placement leads to multiple solutions. The indices can be used to assess multiple solutions of PMU placement from the exhaustive method. In this work, an optimal solution is selected based on the performance of PMU placement in according to the indices. The proposed method is tested on the IEEE 14 bus test system. Only four PMUs are required to monitor the whole test system. However, the number of PMUs can be reduced to three PMUs after applying zero injection bus elimination.
p class="Abstract">Since the previous few decades, researchers and utilities have been extremely concerned about voltage instability because to the numerous instances of system blackouts caused by voltage instability that have been recorded in various regions of the world. With the development of synchro phasor technology, it appears conceivable to track and manage the system's voltage stability in real time. This study suggests using phasor measuring units (PMUs) placed strategically to monitor voltage stability margin online and to regulate it using a static synchronous compensator (STATCOM). According to the minimum reactive and real power loanability for the most of the line outages, STATCOM has been installed at the critical bus. Based on the difference between the bus voltage and its reference value, STATCOM supplies reactive power into the bus. PMU measurements are used to determine bus voltages at regular intervals, and reactive power is then added to the bus online as necessary. The increased voltage stability margin brought on by STATCOM injecting reactive power is continuously checked. Based on simulations performed on the IEEE 14-bus system and the New England 39-bus system, the effectiveness of the suggested approach for online monitoring and management of voltage stability margin (VSM) has been proven.</p
Phasor measurement unit (PMU) technology is a need of the power system due to its better resolution than conventional estimation devices used for wide-area monitoring. PMUs can provide synchronized phasor and magnitude of voltage and current measurements for state estimation of the power system to prevent blackouts. The drawbacks of a PMU are the high cost of the device and its installation. The main aspect of using PMUs in electrical networks is the property to observe the adjacent buses, thereby making it possible to observe the system with fewer PMUs than the number of buses through their optimal placement. In the last two decades, exhaustive research has been done on this issue. Considering the importance of this field, a comprehensive review of the progress achieved until now is carried out and the limitations of existing reviews in the literature are highlighted. This paper can be seen as a major attempt to provide an up-to-date review of the research work carried out in this all-important field of PMU placement and indicates that some perspectives of optimal PMU placement still need attention. Eventually, the work will open a new standpoint for the research community to fill the research gap.
Cell imbalance can cause negative effects such as early stopping of the battery charging and discharging process which can reduce its capacity. In the previous active balancing research, the energy used for the balancing process was taken from the cell or battery pack, resulting in drop of electric vehicle driving range. In this paper, a cell charger based battery balancing system is proposed with a reduction in the number of switches. The use of a cell charger aims to increase the usable energy of the battery pack, since the energy used for the balancing process is taken directly from the grid. The use of fewer switches aims to reduce the cost and space used on the battery management system (BMS) hardware. The charger used for the balancing process has a maximum current of 3 A and a maximum voltage of 3.65 V while the number of switches used is n +5 for n batteries. A 15S1P 200 Ah LiFePO<sub>4</sub> battery pack consists of 15 cells used for testing purpose. The test results show that the time needed to equalize the 15 cell battery voltage reaches 6 hours from the difference between the highest and lowest battery cell voltages of 145.1 mV to 15.1 mV.
