Optimal multistage PMU placement for wide-area monitoring

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Optimal phasor data concentrator installation for traffic reduction in smart grid wide-area monitoring systems

Conference Theme: the Power of Global CommunicationsSymposium on Selected Areas in CommunicationsAs one of the core components in wide-area monitoring systems (WAMS), phasor measurement units (PMUs) acquire highly accurate and time-synchronized phasor data at high frequency for smart grid monitoring, protection, and control. Despite the advantages of PMUs, they do generate much data and create a heavy burden on the communication network. One way of alleviating such burden is to install phasor data concentrators (PDC) across the power system to concentrate data generated by the PMUs. Although PDCs are expensive as well, this may still be a much cheaper and more practical option than building a high bandwidth network for WAMS. Therefore, it is very important to solve the optimal PDC installation problem so as to achieve a desired level of traffic reduction. This paper is the first to address this problem and we give solutions for the IEEE 14-bus, 30-bus, and 57-bus systems.published_or_final_versio

Despliegue óptimo de sincronofasores en un sistema de transmisión eléctrica

This paper proposes a methodology based on increasing need to minimize costs associated with the location of synchrophasor (PMUs) whilst guaranteeing full system observability. It has developed a preliminary approach to solving the problem of optimal placement of PMUs and later optimize the costs of implementation of the communication network (CN). In this context the integer linear programming (ILP) method is proposed, which has been modified and extended in order to determine the optimal location of PMUs by incorporating the effect of zero-injection buses. In addition, the algorithm of minimum spanning tree of Kruskal is implemented to obtain optimal communication networks with minimum investment cost. The effectiveness of the implementation and design of the communication network (CN) is an important factor that directly influences when solving the problem of optimal placement of Sincronofasores, it is for this reason that an analysis of the different WAMS architectures existing is performed, in order to implement the architecture that promotes lower costs and greater observability. The efficiency of the proposed method is verified on real transmission system oversized that covering different voltage levels (138, 230, 500 kV), where geo-referenced data (coordinates) are implemented in transmission substations (buses or nodes ) and transmission lines that make up the grid in order to implement a study model with a distinctly real focus.El presente trabajo propone una metodología basada en la creciente necesidad de minimizar costos asociados a la ubicación de Sincronofasores (PMUs) al tiempo que garantice la observabilidad completa del sistema. Se ha desarrollado un enfoque preliminar para resolver el problema de ubicación óptima de PMUs para posteriormente optimizar los costos de implementación de la red de comunicación. Bajo este contexto se propone el método de programación lineal entera, el cual ha sido modificado y extendido con el fin de determinar la ubicación óptima de las PMUs mediante la incorporación del efecto de barras de inyección cero. Además, se incorpora el algoritmo de árbol de expansión mínima de Kruskal para obtener las redes de comunicación óptimas con un costo de inversión mínimo. La efectividad de la implementación y diseño de la red de comunicación (Communication Network) es un factor importante que influye de manera directa al momento de resolver el problema de ubicación óptima de los Sincronofasores, es por esta razón que se realiza un análisis de las diferentes arquitecturas WAMS existentes con la finalidad de implementar la arquitectura que promueva menores costos y una mayor observabilidad. La eficacia del método propuesto se verifica en un sistema de transmisión real de gran tamaño que abarca diferentes niveles de voltaje (138, 230, 500 kV), donde se aplican datos geo-referenciados (coordenadas) de las subestaciones de transmisión (barras o nodos) y las líneas de transmisión que conforman el sistema interconectado con el fin de implementar un modelo de estudio con un enfoque netamente real

A Decision Modeling For Phasor Measurement Unit Location Selection In Smart Grid Systems

As a key technology for enhancing the smart grid system, Phasor Measurement Unit (PMU) provides synchronized phasor measurements of voltages and currents of wide-area electric power grid. With various benefits from its application, one of the critical issues in utilizing PMUs is the optimal site selection of units. The main aim of this research is to develop a decision support system, which can be used in resource allocation task for smart grid system analysis. As an effort to suggest a robust decision model and standardize the decision modeling process, a harmonized modeling framework, which considers operational circumstances of component, is proposed in connection with a deterministic approach utilizing integer programming. With the results obtained from the optimal PMU placement problem, the advantages and potential that the harmonized modeling process possesses are assessed and discussed

The power system and microgrid protection-a review

In recent years, power grid infrastructures have been changing from a centralized power generation model to a paradigm where the generation capability is spread over an increasing number of small power stations relying on renewable energy sources. A microgrid is a local network including renewable and non-renewable energy sources as well as distributed loads. Microgrids can be operated in both grid-connected and islanded modes to fill the gap between the significant increase in demand and storage of electricity and transmission issues. Power electronics play an important role in microgrids due to the penetration of renewable energy sources. While microgrids have many benefits for power systems, they cause many challenges, especially in protection systems. This paper presents a comprehensive review of protection systems with the penetration of microgrids in the distribution network. The expansion of a microgrid affects the coordination and protection by a change in the current direction in the distribution network. Various solutions have been suggested in the literature to resolve the microgrid protection issues. The conventional coordination of the protection system is based on the time delays between relays as the primary and backup protection. The system protection scheme has to be changed in the presence of a microgrid, so several protection schemes have been proposed to improve the protection system. Microgrids are classified into different types based on the DC/AC system, communication infrastructure, rotating synchronous machine or inverter-based distributed generation (DG), etc. Finally, we discuss the trend of future protection schemes and compare the conventional power systems

Power System State Estimation and Renewable Energy Optimization in Smart Grids

The future smart grid will benefit from real-time monitoring, automated outage management, increased renewable energy penetration, and enhanced consumer involvement. Among the many research areas related to smart grids, this dissertation will focus on two important topics: power system state estimation using phasor measurement units (PMUs), and optimization for renewable energy integration. In the first topic, we consider power system state estimation using PMUs, when phase angle mismatch exists in the measurements. In particular, we build a measurement model that takes into account the measurement phase angle mismatch. We then propose algorithms to increase state estimation accuracy by taking into account the phase angle mismatch. Based on the proposed measurement model, we derive the posterior Cramér-Rao bound on the estimation error, and propose a method for PMU placement in the grid. Using numerical examples, we show that by considering the phase angle mismatch in the measurements, the estimation accuracy can be significantly improved compared with the traditional weighted least-squares estimator or Kalman filtering. We also show that using the proposed PMU placement strategy can increase the estimation accuracy by placing a limited number of PMUs in proper locations. In the second topic, we consider optimization for renewable energy integration in smart grids. We first consider a scenario where individual energy users own on-site renewable generators, and can both purchase and sell electricity to the main grid. Under this setup, we develop a method for parallel load scheduling of different energy users, with the goal of reducing the overall cost to energy users as well as to energy providers. The goal is achieved by finding the optimal load schedule of each individual energy user in a parallel distributed manner, to flatten the overall load of all the energy users. We then consider the case of a micro-grid, or an isolated grid, with a large penetration of renewable energy. In this case, we jointly optimize the energy storage and renewable generator capacity, in order to ensure an uninterrupted power supply with minimum costs. To handle the large dimensionality of the problem due to large historical datasets used, we reformulate the original optimization problem as a consensus problem, and use the alternating direction method of multipliers to solve for the optimal solution in a distributed manner

Chemical reaction optimization for the set covering problem

The set covering problem (SCP) is one of the representative combinatorial optimization problems, having many practical applications. This paper investigates the development of an algorithm to solve SCP by employing chemical reaction optimization (CRO), a general-purpose metaheuristic. It is tested on a wide range of benchmark instances of SCP. The simulation results indicate that this algorithm gives outstanding performance compared with other heuristics and metaheuristics in solving SCP. © 2014 IEEE.postprin