A security-based observability method for optimal PMU-sensor placement in WAMS

A novel comprehensive optimal PMU placement considering practical issues in design and implementation of a wide-area measurement system

This article presents a novel method for optimal phasor measurement unit placement (OPP) for full power system observability in the presence of conventional measurements. The method considers eligible PMU placements that may be omitted by existing OPP methods and hence may provide a better solution and can guarantee that the PMU placement can restore network observability. This is achieved by creating a new observability criterion and a network transformation scheme. The new observability criterion uses injection and zero injection measurements to improve the solution and the network transformation scheme reduces the size of the OPP problem and is a prerequisite for applying the proposed observability criterion. The OPP problem is solved using binary integer linear programming (BILP) or binary integer linear programming (BILP). Therefore, the proposed OPP method can be easily combined with other OPP methods, considering other constraints/scenarios using BILP, such as OPP considering PMU current channel limits. The new method is tested using simulations of the IEEE 14-, 118-, and 2736-bus test systems. These results show that the proposed new method is feasible in terms of execution time, is free of solutions that fail to make the system fully observable, and is capable of identifying optimal placement solutions that may be overlooked by existing OPP methods.

This paper presents a detailed bibliographic analysis of papers concerning the optimal PMU placement (OPP) problem that have more than ten citations and sorted in descending order by the number of citations. The results from this analysis show that IEEE journal and IEEE conference papers are the most influential. The most productive and high-impact authors, institutions, and countries/regions are also identified. According to this analysis, U.S.A. researchers and institutions dominate the research on OPP problem, whereas the most productive and influential authors are A. Abur and B. Gou. Moreover, Texas A&M University, Virginia Polytechnic Institute & State University, and University of Cyprus are the three most productive and influential institutions in OPP research.

<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>

This paper presents the optimal phasor measurement (PMU) placement for distribution networks. The optimal PMU placement (OPP) formulation from related literatures is presented in integer linear programming (ILP) framework where zero injection buses (ZIBs), PMU channel limitation, PMU outages and line outages were considered. Existing methods for OPP search space reduction (OPPSSR) such as the predetermined buses, ZIBs and leaf buses are also presented. To further reduce the search space for OPP, a method network reduction and deterministic PMU placement were proposed in dealing with non- branching bus series (NBS) that may be present in radial systems such as large distribution networks. Results have shown that the proposed OPPSSR methods was able to give the same optimal solutions with reduced amount of optimization.

Optimal PMU placement for power system observability using BICA, considering measurement redundancy

The pursuit of achieving total power network observability in smart grids using Phasor Measurement Units (PMUs) carries a significant promise of real-time Wide-Area Monitoring, Protection, and Control (WAMPAC). PMU applications eliminate periodical measurements, thereby increasing accuracy through a high sampling rate of the measured power systems quantities. The high costs of installation of PMUs for total power system observability presents a challenge in the implementation of PMUs. This is due to the expensive costs of PMU devices. This has led to a prominent optimal PMU placement (OPP) problem that researchers tirelessly aim to solve by ensuring a complete power network observability while using the least installed PMU devices possible. In this paper, a novel Binary Firefly Algorithm (BFA) based on the node degree centrality scores of each bus is proposed to minimize PMU installations. The BFA solves the OPP problem in consideration of the effect of Zero Injection Buses (ZIBs) under normal operation and single PMU outage (SPO). The robustness and efficiency of the proposed algorithm is tested on IEEE-approved test systems and visualized with a force-directed technique on an undirected power network graph. The proposed BFA yields the same but better optimal PMU numbers, obtained by existing meta-heuristic optimization techniques found in the literature for each of the IEEE test cases, as well as highlighting the cost–benefit of having a robust system against single PMU loss while considering the ZIB effect for an improved system measurement availability.

The ability of data recovery during communicational failures is one of the significant advantages of the wide area measurement system (WAMS) with hierarchical structure. For this purpose, in addition to the proper partitioning of the WAMS, the relative location of phasor measurement units (PMUs) and phasor data concentrators (PDCs) should be selected so as to maximize the reliability of the communication network. The aim of this paper is to develop an organized method for partitioning the WAMS as well as proposing a new algorithm for the simultaneous optimal placement of PMUs and PDCs. In the proposed method, first it is assumed that PMUs are installed at all of the system buses. Then, redundant PMUs will be omitted sequentially to provide the system observability with the maximum communication reliability. The IEEE 30-, and 118-bus systems are used to demonstrate the proposed algorithm. Contingencies such as PMU loss and line outage are considered in power system observability achievement. Finally, to show the applicability of proposed methods to real dimensional power systems, the IEEE 300-bus power system is also analyzed in the normal operating condition.

Phasor Measurement Unit (PMU) is a measurement devices capable of providing measurements with high accuracy, but due to its high cost it is desired to find the optimal placement for them. This paper tries to address the Optimal PMU Placement (OPP) for large power systems while including additional criteria like injection measurement, as well as, considering the Zero Injection Bus (ZIB) effect. The selected large power system is the Qatar Grid and the system is solved using Integer Linear Programming (ILP) techniques. The paper does not only focus on the number of PMU s required for full observability, it extends to take into consideration N−1 contingency. It also measures the ratio of conventional measurements to PMU s for the Qatar Grid in order to provide an estimate for this ratio. The paper is concluded with the obtained results as well as recommendations for practical application of OPP.

Phasor measurement units (PMUs) are becoming popular and populating the power system grids rapidly due to their wide range of benefits and applications. This research paper proposes a comprehensive, effective, and revised formulation of the optimal PMU placement (OPP) problem with a view to minimizing the required number of PMU and ensuring the maximum number of measurement redundancy subjected to the full observability of the distribution grids. The proposed formulation also incorporates the presence of passive measurements/zero injection buses (ZIB) and the channel availability of the installed PMU. Additionally, the formulation is extended to various contingency cases i.e., the single line outage and single PMU loss cases. This paper solves the proposed OPP formulation employing a heuristic technique called backtracking search algorithm (BSA) and tests its effectiveness through different IEEE standard distribution feeders. Additionally, this study compares the obtained results with the mixed integer linear programming (MILP)-based approach and the referenced works. The obtained results demonstrate the superiority of the proposed formulation and solution methodology compared to other methodologies.

This paper presents a study on optimal placement of phasor measurement units (PMU) with Global Positioning System (GPS) receivers for more accurate monitoring of a power system. The optimal PMU placement (OPP) problem is, in general, expressed as a combinatorial optimization problem subjected to the observability constraints of the studied power system, which consumes much time to solve. Three approaches, in this paper, are proposed aiming at reducing computational burden in OPP problems. First, a modified simulated annealing (MSA) method, is proposed. The conventional simulated annealing method is slightly modified in setting the initial temperature and in cooling procedure to consider the current state of solution sets. Second, a direct combination (DC) method is suggested using a simple but very effective heuristic rule. When selecting test and neighboring solution sets, this heuristic rule is used to select most effective sets in the observability sense. And the last one is tabu search (TS) method, in which the heuristic rule used in DC method is also used to reduce the searching spaces effectively. Suggested optimization methods are applied, in this paper, to solve OPP problems in IEEE 14, 30 and 57 bus systems. The simulation results show that the proposed methods can find the optimal solutions in an efficient manner.

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.

Application of heuristic algorithms to optimal PMU placement in electric power systems: An updated review

In this paper, a practical model for the problem of Optimal PMU Placement (OPP) is proposed. Most of the well-studied OPP models have been developed based on the standard small test systems with minimum focus on the practical points of view and implementation challenges. Therefore, the practical points of view such as phased installation of PMUs based on voltage levels, buses preconditioning, PMUs outage contingencies, etc., are considered in this paper to modify the problem objective function and constraints and improve the model. A practical implementation for this model is also proposed in the paper. The proposed model and implementation are tested in multiple small- and large-scale test systems such as IEEE 14-, 30-, 57-, 118-, and 300-bus test systems as well as WECC 240-bus test system. Five test cases are designed to reflect different practical conditions in the OPP problem. Results of different case studies on different test systems confirm that the proposed model and implementation not only cover the practical scenarios, but also improve the performance in terms of minimizing the number of PMUs in some scenarios for large-scale systems.

Post-mortem studies carried out after recent power system blackouts have shown that time-stamped measurements from Phasor Measurement Units (PMUs) would have helped to avert these blackouts if they were available. Consequently, there is the need to optimally locate these PMUs to provide information about the system’s state. This paper proposes a novel method incorporating modal participation factors computed from the eigenvalues and eigenvectors of the reduced Jacobian matrix obtained from the system’s power flow with Binary Integer Programming (BIP), in solving the Optimal PMU Placement (OPP) problem while considering the system’s voltage stability. The proposed method identifies the critical buses prone to voltage instability, determines the minimum number of PMUs required for complete topological observability, and the best locations to site the PMUs. The proposed method was tested on benchmark IEEE 14-bus, 30-bus, and 57-bus test networks. Analyses of the results show that the proposed method provides a better procedure for the strategic placement of PMUs in practical networks for voltage stability monitoring especially for the cases of phased (multi-stage) PMU placement limited by the availability of funds and communication channels. Thereby making it necessary to give priority to critical/voltage weak buses during the phased installation process.