Phasor Measurement Units Placement Research Articles

Tri-Objective Optimal PMU Placement Including Accurate State Estimation: The Case of Distribution Systems

This paper presents a tri-objective Optimal Phasor Measurement Units (PMUs) Placement (OPP) strategy that is focused on the minimization of i) the total number of PMU channels, ii) the maximum state estimation uncertainty based only on high-rate PMU data and iii) the sensitivity of state estimation to line parameter tolerances. The proposed formulation keeps into account system observability with and without contingencies due to single-line and PMU faults. Also, it includes the effect of possible zero-injection buses and a-priori constraints on both the number of PMU channels and the type of PMU measurements performed at each bus. Due to the nonlinear combinatorial nature of the proposed OPP problem, this is solved through a custom implementation of the nondominated sorting genetic algorithm II (NSGA-II). The analysis of the proposed OPP strategy is focused on distribution systems. The placement results obtained using four test systems of different size show that increasing the number of buses instrumented with PMUs and/or the number of PMU channels beyond given thresholds just leads to larger costs with negligible further reductions in both state estimation uncertainty and sensitivity to line parameters tolerances. Moreover, if PMUs with just two three-phase channels are used, we can avoid instrumenting between 30% and 40% of buses with a minor impact on state estimation performance even in the case of contingencies. This percentage can be slightly increased if multi-channel PMUs are used. However, this choice generally is not profitable.

Optimal Phasor Measurement Unit Placement Using a Honey Bee Mating Optimization (HBMO) Technique Considering Measurement Loss and Line Outages

Phasor measurement units (PMUs) are important devices for protection, monitoring, and control of modern power systems. Unlike the supervisory control and data acquisition (SCADA) system which only measure the magnitude, PMUs can provide a set of synchronized phasor measurements with high sampling rate with the accuracy of less than one second, for better system monitoring especially during the outages. Since the PMUs are costly devices, system operator is not able to install a PMU at each bus to maximize the observability of system. To this end, determination of the number of PMUs in the system for having a 100% observability is pivotal. In this paper, honey bee mating optimization (HBMO) approach is utilized to allocate PMUs in modern power systems. Moreover, the impact of line outages, as well as measurement loses, are considered. The simulation results show the effectiveness of the proposed method on solving the PMU placement problem. http://www.crpase.com/xml/20210701211.xml

A Novel Algorithm for Optimal Phasor Measurement Unit Placement for Full Power System Topological Observability

A Novel Algorithm for Optimal Phasor Measurement Unit Placement for Full Power System Topological Observability

Power and Voltage Estimation of Unobserved Bus on Distribution Network Using ANFIS Algorithm with the Modified PSO-GA Hybrid

Power and voltage estimation is a procedure for estimating the voltage of all buses in an electric power system based on measurements made on several buses. The voltage and the current on the bus are measured by a measuring device called the Phasor Measurement Unit (PMU). The Surabaya-Indonesia Bendul-Merisi distributed network has become the object of research for optimizing PMU placement by dividing into 3 clusters and placing 3 PMU on selected buses as observed buses. In this study, power and voltage estimation is done on buses that are not installed PMU (unobserved bus) using ANFIS algorithm with modified PSO-GA hybrid. This algorithm is used because of its ability to get predictive values with high accuracy and speed in achieving convergence. Input data for the estimation process are the voltage and current of all the buses. There are 10 data sets, divided into 7 training data and 3 test data. Estimation results compared with measurement results show a high degree of accuracy. The average accuracy of estimation results for power to 3 clusters is 99.968%, while the estimated accuracy for voltage is 99.758%.

Optimal Allocation of Synchrophasor Units in the Distribution Network Considering Maximum Redundancy

Phasor Measurement Unit (PMU) is a smart measuring device commonly used in wide-area monitoring systems. It provides the synchronized phasor values and the magnitudes of voltages and currents in real-time for the proper state calculation of the electrical network in a common time reference frame. But in order to avoid unnecessary placements, minimize installation cost, and due to the lack of communication facilities at the substations, the placing of PMUs at every location is not possible. Therefore several optimization techniques have been developed to solve the Optimal PMU Placement (OPP) problem. The OPP problem aims to reduce the number of PMUs by achieving a completely observable network. Many solutions to the OPP problem have been proposed for the transmission networks with the use of conventional and heuristic-based approaches, but very few for distribution networks. In this paper, the Binary Grey Wolf Optimization (BGWO) algorithm is proposed to solve the OPP problem considering the measurement redundancy (MR) to achieve complete observability of the distribution network. Finally, case studies have been done by implementing the proposed algorithm on different IEEE test feeders such as the IEEE -13, -33, -37, and -123 node feeder systems. The obtained results are compared with previous studies to verify the feasibility and efficiency of the proposed technique.

A Bounded Exhaustive Search Technique for Optimal Phasor Measurement Unit Placement in Power Grids

This paper proposes a technique to determine the possible optimal placement of the phasor measurement unit (PMU) in power grids for normal operating conditions. All possible combinations of PMU placement, including infeasible combinations, are typically considered in finding the optimal solution, which could be a massive search space. An integer search algorithm called the bounded search technique is introduced to reduce the search space in solving a minimum number of PMU allocations whilst maintaining full system observability. The proposed technique is based on connectivity and symmetry constraints that can be derived from the observability matrix. As the technique is coupled with the exhaustive technique, the technique is called the bounded exhaustive search (BES) technique. Several IEEE test systems, namely, IEEE 9-bus, IEEE 14-bus, IEEE 24-bus and IEEE 30-bus, are considered to showcase the performance of the proposed technique. An initial Monte Carlo simulation was carried out to evaluate the capability of the bounded search technique in providing a smaller feasible search space. The effectiveness of the BES technique in terms of computational time is compared with the existing exhaustive technique. Results demonstrate that the search space can be reduced tremendously, and the computational burden can be eased, when finding the optimal PMU placement in power grids.

Weak bus-constrained PMU placement for complete observability of a connected power network considering voltage stability indices

Phasor measurement units (PMUs) are preferred for installation at weak buses in a power network. Therefore, the weak buses need to be located and the strategic locations of PMUs identified to ensure network observability. Thus, the primary aim of this work is to identify the placements of the maximum number of PMUs installed at the weak buses in the electrical network. The voltage collapse proximity indicator, line stability index, fast voltage stability index, and a new voltage stability indicator utilizing load flow measurement are used to determine the weak buses. A novel deterministic methodology based on a binary-integer linear programming model is then proposed to determine the optimal locations of PMUs. The effect of a single PMU outage considering the weak buses is also demonstrated. The effectiveness of the developed approach is tested and validated on the standard IEEE 14-, 118-, 300-, and New England 39-bus systems. The obtained results are also compared to those using different weak bus methodologies.

A critical review of methods for optimal placement of phasor measurement units

A critical review of methods for optimal placement of phasor measurement units

Economic Analysis of a Power System Network using Optimal Placement of PMUs and DULRs Through Complete and Incomplete Observability Analysis

For power system operation and control State estimation has become essential in recent days. To evaluate this State estimation, to reach out and recorder system status Supervisory Control and Data Acquisition and Energy Management System are intended due to which are operated at specified time. Phasor Measurement Unit is one of the crucial techniques for auditing a system. To make system performance is honest, keeping Phasor Measurement Units in a system is very much helpful, and that will be intended to help operating time reduced by very much. Due to this another problem may arise, that is substation updating cost may increase due to these Phasor Measurement Units. In this paper an optimal set of Phasor Measurement Units along with optimal locations Dual Use Line Relays are achieved for complete economic analysis of a power network using both complete and incomplete observability analysis. No of Phasor Measurement Units required to attain the complete perceptibility of a network are considerably diminished using incomplete observability analysis. To test IEEE 14, 24, 30, 57 and both SR and sub systems 1, 2 with a size of 270 and 444 buses, the recommended complete and incomplete observability analysis are used to place Phasor Measurement Units. Similarly IEEE 14, 30 and 57 bus systems are considered for both Phasor Measurement Units and Dual Use Line Relays placement. Also single Phasor Measurement Unit loss condition is considered by using complete observability analysis.

Optimal PMU placement approach for power systems considering non-Gaussian measurement noise statistics

This paper investigates how to add a limited number of Phasor Measurement Units (PMUs) to the existing monitoring system so as to improve the estimation accuracy further. The existing methods are usually based on Gaussian noise assumption and the weighted least squares (WLS) estimator is taken into account. However, the Gaussian noise assumption is not always true in reality and the WLS is non-robust in this case. This paper proposes a new optimal PMU placement approach where the distribution of measurement noise can be non-Gaussian or Gaussian and many robust estimators such as the maximum likelihood estimator, Multiple-Segment, Quadratic-Linear, Square-Root and Schweppe-Huber Generalized-M estimator are considered. Based on the new Gain matrix obtained from the influence function approximation, the D-optimal and E-optimal experiment criterions are exploited in the optimal PMU placement problem. A convex relaxation in conjunction with an optimization improvement method based on the Fedorov exchange algorithm is utilized to solve the optimizing problem. Simulations on the IEEE 57-bus system and the Polish 2383-bus system are carried out to evaluate the effective performance of the proposed approach.

Optimal PMU arrangement considering limited channel capacity and transformer tap settings

The transition from the conventional power systems to smart grids has led to the modernisation of the measuring infrastructure used for their monitoring and control. Among the devices used to accomplish these tasks, phasor measurement units (PMUs) play a key role since they can provide extremely accurate synchronised voltage and current phasor measurements. The optimal PMU placement (OPP) problem, which focuses on minimising the number of PMUs for full system observability, has long been a popular research topic. The vast majority of the available OPP techniques have treated each transformer tap setting (voltage turns ratio and phase-shifting angle) as a fixed network parameter. Such an assumption can lead to misdirecting residuals in adjacent valid measurements when the modelled tap setting is incorrect. The aim of this study is to propose a substation-oriented OPP method based on a binary semidefinite programming algorithm, considering the observability of the transformer tap settings and the limited PMU channel capacity. The method is illustrated using an 8-bus test system. Numerical results using different size IEEE systems are presented and discussed. The proposed approach is further applied to the Polish 3120-bus system to show its efficacy in solving the OPP problem for large-scale power systems.

Critical Elements Based Optimal PMU Placement Considering Substation Coverage

The Phasor Measurement Unit (PMU) is becoming the most prominent tool for power system applications like power system operation, control, and protection. In a robust and accurate wide-area measuring system, the PMU should observe not only the elements in its substation but also the critical elements and its incident busses. As the PMU cost limits their deployment, they must be installed optimally considering the substation installation and the critical lines in the power system. This paper introduces a new Optimal PMU Placement algorithm considering the optimal substations and the critical elements. This has been done based on the assumption that there must be a PMU in each constructed substation (optimal substation). This will assure the observability of all the elements in the substation. The proposed method has been tested on some standard test systems and then applied to a practical regional Indian grid.

Novel multi-objective phasor measurement unit placement for improved parallel state estimation in distribution network

Due to the lack of enough metering devices in the distribution networks compared with the transmission networks, it is burdensome to estimate the clustered distribution network state. This subject could lead to biased state estimation in the multi-area state estimation problem. This paper proposed a novel multi-objective function for phasor measurement unit placement involving all the state estimation error components (estimation error variance and estimation bias). The developed adaptive decision coefficients weighted different state quantities in the proposed function based on their contributions in the estimation error. The proposed objective function was compared with two known functions including minimizing estimation error variance and minimizing the maximum value of estimation deviation. The obtained results on IEEE 33 and UKGDS 356 node networks verified the effectiveness and comprehensiveness of the proposed method in clustered distribution networks.

Secondary and Tertiary Voltage Control of a Multi-Region Power System

This paper presents techniques for the application of tertiary and secondary voltage control through the use of intelligent proportional integral derivative (PID) controllers and the wide area measurement system (WAMS) in the IEEE 39 bus system (New England system). The paper includes power system partitioning, pilot bus selection, phasor measurement unit (PMU) placement, and optimal secondary voltage control parameter calculations to enable the application of the proposed voltage control. The power system simulation and analyses were performed using the DIgSILENT and MATLAB software applications. The optimal PMU placement was performed in order to apply secondary voltage control. The tertiary voltage control was performed through an optimal power flow optimization process in order to minimize the active power losses. Two different methods were used to design the PID secondary voltage control, namely, genetic algorithm (GA) and neural network based on genetic algorithm (NNGA). A comparison of system performances using these two methods under different operating conditions is presented. The results show that NNGA secondary PID controllers are more robust than GA ones. The paper also presents a comparison between system performance with and without secondary voltage control, in terms of voltage deviation index and total active power losses. The graph theory is used in system partitioning, and sensitivity analysis is used in pilot bus selection, the results of which proved their effectiveness.

A PMU-Based Data-Driven Approach for Classifying Power System Events Considering Cyberattacks

Transient event identification is essential for power system operation and situational awareness. The increased penetration of the high sampling frequency phasor measurement units (PMUs) enables using PMU data to analyze power system events, and thus enhances power system visualization, monitoring and control. At the same time, the risks associated with cyberattacks on power systems increase. A malicious cyberattack on PMUs, aiming at generating fake transient data, may lead to incorrect actions that jeopardize system reliability. Therefore, it is critical to distinguish between fake data and real data when analyzing transient events. Utilizing PMU measurements, this article develops a data-driven approach, based on text-mining methodologies, for classifying transient events and identifying fake events caused by false data attacks. The developed methodology provides credible information regarding the cause of various events, and facilitates postevent decision-making to prevent potential cascading failures. Case studies, performed on the IEEE 30-bus and IEEE 118-bus systems, show that the developed approach is efficient in classifying false data and identifying different transient events regardless of the system topology, loading conditions, or the placement of PMUs.

Secondary Voltage Control Application in a Smart Grid with 100% Renewables

This paper presents secondary voltage control by extracting reactive power from renewable power technologies to control load buses voltage in a power system at different operating conditions. The study is performed on a 100% renewable 14-bus system. Active and reactive powers controls are considered based on grid codes of countries with high penetration levels of renewable energy technologies. A pilot bus is selected in order to implement the secondary voltage control. The selection is based on short-circuit calculation and sensitivity analysis. An optimal Proportional Integral Derivative (PID) voltage controller is designed using genetic algorithm. A comparison between system with and without secondary voltage control is presented in terms of voltage profile and total power losses. The optimal voltage magnitudes at busbars are calculated to achieve minimum power losses using optimal power flow. The optimal placement of Phasor Measurement Units (PMUs) is performed in order to measure the voltage magnitude of buses with minimum cost. Optimization and simulation processes are performed using DIgSILENT and MATLAB software applications.

Optimal placement of PMU for complete observability of the interconnected power network considering zero-injection bus: A numerical approach

<div data-canvas-width="397.3623059866966">This paper presents an approach to place the phasor measurement unit (PMU)</div><div data-canvas-width="397.3623059866962">optimally, which minimizes the setup cost of PMU. This methodology attains complete state estimation of the interconnected power networks. An integer linear programming (ILP) method is explored for the optimal PMU placement problem. It is used to determine the optimal location and minimum number of PMUs necessary to make the interconnected power network completely observable. ILP may provide many solutions if acquainting buses to zero injection buses are unhandled. In the case of more than one solution, a bus observability redundancy index and total system observability redundancy index is proposed to find the most promising solutions set for redundancy measurement. The proposed algorithm is applied to benchmark the optimal PMU placement solutions for the IEEE 14-bus, IEEE 30-bus, New England 39-bus, IEEE 118-bus, and NRPG 246-bus test systems. The obtained results of the proposed approach are compared with the existing standard algorithm, and it is observed that the proposed approach achieves complete observability of the interconnected power network under base-load conditions.</div>

Connectivity Matrix Algorithm: A New Optimal Phasor Measurement Unit Placement Algorithm

The maximum benefits of the phasor measurement unit (PMU) in state estimation and other applications in the power system can be achieved if the system is completely observed by PMUs only. The minimum number of PMUs needed to obtain full observability is very important in order to reduce the overall cost. This paper presents a new algorithm for optimal PMU placement (OPP) in transmission and distribution systems. A new concept and vision of the optimization problem is presented. A new approach to implement zero-injection buses is proposed which may be also used in other algorithms. The simulation result of IEEE 14, 24, 30, 57 and 118 bus systems as transmission systems, IEEE 33, 34 and 123 bus systems as distribution systems, and Jordanian power system as an actual system are presented and compared with the existing techniques. The proposed technique is simple to implement and accurate compared to other existing methods. The results confirm the efficiency of the proposed algorithm. The computational time is less than 0.2 seconds for all cases. MATLAB 2016a is used to validate the algorithm.

Cost-Effective Placement of Phasor Measurement Units to Defend against False Data Injection Attacks on Power Grid

This study presents the phasor measurement unit (PMU) placement strategy in the presence of false data injection attacks which is one of the most serious security threats against power grid. It is focused on applications related to supervisory control and data acquisition (SCADA) systems where measurement data can be easily corrupted by adversaries without getting caught by the system. To safeguard power grids against malicious attacks, procedures have been proposed to facilitate the placement of secure PMUs to defend against false data injection attacks in a highly cost-effective way. It has formulated a method of identifying measurements that are vulnerable to false data injection attacks. It was discovered that a weak power grid can be transformed into a robust power grid by adding a few PMUs at vulnerable locations. Simulations on the IEEE standard test systems demonstrate the benefits of the proposed procedure.

A Strategic and Significant Method for the Optimal Placement of Phasor Measurement Unit for Power System Network

Currently the new state of power system relies on a precise monitoring of electrical quantities such as voltage and current phasors. Occasionally, its operation gets disturbed because of the flicking in load and generation which may result in the interruption of power supply or may cause catastrophic failure. The advanced technology of phasor measurement unit (PMU) is introduced in the late 1990s to measure the behavior of power system more symmetrically, accurately, and precisely. However, the implementation of this device at every busbar in a grid station is not an easy task because of its expensive installation and manufacturing cost. As a result, an optimum placement of PMU is much needed in this case. Therefore, this paper proposes a new symmetry approach of multiple objectives for the optimum placement of PMU problem (OPPP) in order to minimize the installed number of PMUs and maximize the measurement redundancy of the network. To overcome the drawbacks of traditional techniques in the proposed work a reduction and exclusion of pure transit node technique is used in the placement set. In which only the strategic, significant, and the most desirable buses are selected without considering zero injection buses (ZIBs). The fundamental novelty of the proposed work considers most importantly the reduction technique of ZIBs from the optimum PMU locations, as far as the prior approaches concern almost every algorithm have taken ZIBs as their optimal placement sets. Furthermore, a PMUs channel limits and an alternative symmetry location for the PMUs placement are considered when there is an outage or PMUs failure may occur. The performance of the proposed method is verified on different IEEE-standard such as: IEEE-9, IEEE-14, IEEE-24, IEEE-30, IEEE-57, IEEE-118, and a New England-39 bus system. The success of the proposed work was compared with the existing techniques’ outcomes from the literature.