Sharif Digital Repository

In this paper, the problem of placing a minimum number of phasor measurement units (PMUs) in a transmission system is considered so that faults on all lines of the network can be diagnosed and located irrespective of their locations. For this purpose, a PMU placement algorithm is applied to calculate the required data for impedance-based fault location of any fault line in the network, achieving the full potential of the circuit laws throughout the system. Another algorithm is then proposed to compute the voltage and current values of the fault line for fault-location purposes. Moreover, as many networks are already equipped with PMUs, the proposed algorithm makes it possible to locate... 

Placement of phasor measurement units (PMUs) in power systems has often been formulated for achieving total network observability. In practice, however, the installation process is not implemented at once, but at several stages, because the number of available PMUs at each time period is restricted due to financial problems. This paper presents a novel integer linear programming framework for optimal multi-stage PMU placement (OMPP) over a preset schedule, in order to improve the network observability during intermediate stages, in addition to its complete observability by the end of the PMU placement process. To precisely evaluate the network observability and fully exploit the potential of... 

Due to the lack of data in active distribution networks, employing new accurate measurement devices like phasor measurement units (PMUs) and micro-PMUs with a high reporting rate becomes an inevitable choice for the future vision of distribution systems. As a result, different algorithms have been presented to optimally place PMUs cost-effectively based on the estimation errors of the distribution state estimation (DSE) results. However, any component failure in measurement devices or communication links between sending ends and monitoring system of the distribution management system can significantly affect the DSE results. In response, this study introduces the reliability of satisfying... 

Small signal stability of power systems is one of the most crucially important issues, since the electrical demand is increasing at a galloping rate and power systems are expanding day by day. In this regard, estimation of dampings and frequencies of electromechanical modes through the analysis of field measurements has become a heated study topic for electrical power system researchers in recent years. There have been several methods to analyze different types of Phasor Measurement Units (PMUs) signals i.e., transient, ambient, and probing. Among the proposed techniques, those which are capable of analyzing ambient data seems to be more practical, since this type of data can be achieved... 

With the rapid advancement of phasor measurement units (PMUs) technology, system operators in different level of power systems have access to new and abundant measurements. Taking into account these measurements in active distribution systems (ADNs), a new algorithm for short-circuit fault detection and identification based on state estimation (SE) is introduced in this paper. In this regard, as the first step, traditional SE process is revised to be compatible with fault conditions. Then, a fault location algorithm (FLA) based on the revised SE (RDSSE) is presented which attends to detect the location of fault after diagnosing faulted zone. For this purpose, current and voltage... 

This paper utilizes data measured by phasor measurement units (PMUs) to extract a low-order dynamic equivalent model for power system stability studies. The estimated model is a 2-order model for synchronous machines. This model has the advantage of simplicity of classical model and considerably reduces the oversimplifying error of classical model. This method offers an alternative approach to analytical model reduction techniques based on the detailed system models. The proposed method uses the synchronized bus voltage and current phasors measured by PMUs. Using post disturbance data, electrical and mechanical parameters of the equivalent generator are estimated sequentially. Furthermore, a... 

This paper presents an integer linear programming (ILP) framework for the optimal placement of phasor measurement units (PMUs), in the presence of conventional measurements. Furthermore, by the proposed method, the power system remains completely observable during all possible single contingencies for lines and measurement devices. In doing so, the potential of circuit equations associated with both PMUs and conventional measurements as well as the network topology are fully utilized by a system of equations to reach the minimum possible numbers of required PMUs. The limitation of communication channels is also taken into account in the proposed ILP-based framework. The method is implemented... 

While the importance of wide area measurement system (WAMS) consisting of phasor measurement units (PMUs) is recognized, there are still unidentified applications that can be addressed with the advance of technology. Traditionally, power system operators diagnosed the fault point through the status of protective relays and circuit breakers of the protection system. In large blackouts, however, the malfunction of protection system has itself often been among the suspects of the disaster. This paper proposes an alternative fault diagnosis approach independent of the function of protection system, utilizing PMU data and bus impedance matrix (Zbus). First, the proposed method diagnoses the fault... 

This paper introduces a novel approach for power system fault diagnosis based on synchronized phasor measurements during the fault. The synchronized measurements are obtained in real time from Phasor Measurement Units (PMUs) and compared with offline thresholds determined by decision trees (DTs) to diagnose the fault. The DTs have already been trained offline using detailed power system analysis for different fault cases. While the traditional methods for fault diagnosis use the status of protective relays (PRs) and circuit breakers (CBs) to infer the fault section in the power system, the proposed method uses the available signals following the fault and thus can be trusted even in case of... 

This study presents optimal placement of Phasor Measurement Units (PMUs) for the purpose of power system observability using topology based formulated algorithms. The optimal PMU placement problem is formulated to minimize the number of PMUs installation subject to full network observability. The Branch and Bound (B and B) and genetic algorithm optimization methods are selected to solve the problem, which are suitable for problems with integer and Boolean variables. Topology-based algorithm used for observability analysis and a hybrid method of topology transformation and nonlinear constraint is used to form constraints. The IEEE 14, 30, 57 and 118-bus and the New England 39-bus test systems... 

One of the most important applications of phasor measurement units (PMUs) is power system state estimation. Some models have been proposed for including phasor measurements in the state estimation. But, all of these models have treated transformer tap settings (voltage transformer turns ratio and phase-shift transformer angle) as fixed parameters of the network. The accuracy of state estimation may decrease when a tap changes or the true value is unknown. In this paper, each transformer tap setting is added as a new state variable to the states vector, converting the linear PMU based state estimation to a nonlinear one. Also, the network observability is analyzed including the observability...