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There are many entities in the modern power systems that collaborate together to operate the system in a secure and reliable manner. Each of the entities is managed and operated autonomously and intends to increase its own benefit. This paper presents a system of systems (SOS) framework for optimal operation of distribution grids. The distribution grids are modeled as the SOS utilized by distribution companies (DISCOs) collaborating with different loads and microgrids. In this framework, the DISCO and microgrids are regarded as the individual systems which are independently managed and operated aiming at maximizing their own profit. Considering the correlation among the independent systems, the ORIGIN and CLIENT data are introduced and the relationship table is constructed to represent the correlated variables between the entities. The relationship table indicates the sequences of the optimization problems for the entities. The proposed framework is applied to a typical distribution grid and results are discussed. [ABSTRACT FROM PUBLISHER]

This paper focuses on recognizing the ways in which information and communication network failures cause a loss of control over a power system's operation. Using numerical evidence, it also assesses the specific impacts of such failures on the optimal operation of a power system. Optimal power flow (OPF) is the most prominent method for implementing optimal operation. In OPF, it is assumed that all power appliances are accessible through the communication and information network, and all power devices are set as the output of OPF; nevertheless, the loss of control and operation of the power system's apparatuses may seriously impact the real-time operation of the bulk power system. The control and operation of the power system is dedicated to a modern communication network, in that intelligent electronic devices (IEDs) are connected to apparatuses of the power network. Data communication among IEDs enables both automatic and remote manual control of the power system. Although such a network offers new advantages and possibilities not previously achievable, it intrinsically has its own source of failures, such as the failure of physical components, loss of integrity, software failures and data communication faults. [ABSTRACT FROM PUBLISHER]

Power system protection is a mission critical task that must be accomplished within the specified time limits so as to maintain the stability, reliability, and safety of the grid. As modern substations embrace the integrated communications and LAN-based substation automation systems using IEC61850 standard, the network latency and reliability issues continue to influence the decision making process to move the critical protection tasks to LAN-based substation automation systems (SAS) and eliminate the laborious and costly copper hard-wiring in the substations. Backup protection functions such as circuit breaker failure (CBF) protection seems to be a good candidate to implement in SAS to gain the operational experience with the new paradigm. CBF protection is a deferred protection function and can tolerate variations in network latency with proper design. This paper explores this application and offers two metrics to assess availability followed by presentation of a case study to illustrate the concepts and this particular application. [ABSTRACT FROM PUBLISHER]

The idea of connecting some adjacent microgrids and making a multi-microgrid (MMG) have recently attracted attention among power system researchers. It helps better operate, control and manage the power system. This paper presents a multiobjective optimal power flow (MOPF) algorithm for improving the performance of MMGs incorporating interline power flow controller (IPFC). The proposed MOPF simultaneously minimizes MMG operating cost and total energy loss, as well as voltage profile deviation of all buses in the system. The proposed multiobjective nonlinear constraint optimization problem is formulated considering the control variables of IPFC. Also, the proposed algorithm guarantees that the final system operating point has a suitable security margin from the voltage instability point. A typical MMG system is used to demonstrate the effectiveness and proficiency of the algorithm. [ABSTRACT FROM PUBLISHER]

This paper proposes a stochastic multiobjective optimization algorithm for simultaneous active and reactive power dispatch in electricity markets with wind power volatility. Considering only economic issues during market clearing will achieve minimum system payment but may not yield an efficient and secure system operating point. Therefore, maximizing expected voltage security margin and minimizing transmission congestion probability are incorporated into the proposed multiobjective function. To demonstrate the effectiveness of the proposed algorithm, five average deviation indices and a spider diagram are introduced to evaluate the proposed algorithm. [ABSTRACT FROM PUBLISHER]

In recent decades, the integration of renewable energy resources in the power system has grown rapidly around the globe. Using renewable energy resources in microgrids is appropriate, especially where access to public power energy is impossible or costly. This paper presents a novel method for assessing the reliability of microgrids, taking into account the probabilistic behavior of solar and wind power. In this model, the study period is divided into different Timeframes (TFs), and for each TF, the timeframe capacity factor (TFCF) is considered for each renewable energy resource. To assess the microgrid's reliability, the Loss of Load Expectation (LOLP) and Expected Energy Not Supplied (EENS) are calculated. Compared to existing probabilistic models, the prerequisites data and running time for reliability assessment is significantly reduced when using the proposed method. These two virtues suit the model well for optimization-based planning problems. [ABSTRACT FROM PUBLISHER]

This paper deals with stochastic latency in modern substation automation systems based on IEC61850. In order to meet the real-time requirements of mission-critical protection functions, latency evaluations are necessary to assess the expected performance level. A thoroughly-analyzed system under various contingencies ascertains that the communications design architecture is sufficiently fast and reliable. The presented methodology is demonstrated via a case study related to anti-islanding protection of a power plant. The base case latency and stochastic latency were calculated and compared. This investigation reveals that a failure in the communications network can compromise the performance of the protection function without proper mitigation strategies such as utilizing devices with higher reliability, considering redundant parts, equipping network devices with monitoring and indication systems, and deploying GOOSE as opposed to ARQ. [ABSTRACT FROM PUBLISHER]

A cyber-power system, a type of cyber-physical system, contains two interconnected infrastructures: a power network and a cyber network. The cyber network monitors, protects and controls the power network. Without the cyber network, the power network cannot operate efficiently or reliably. This paper studies the cyber-power interdependencies in smart grids and categorizes four types of interdependencies between cyber and power networks. The proposed classification permits the assessment of adverse effects of cyber network failures on the power network's operation. Two applications of cyber-power systems, automated substations and micro grids, are discussed in this paper, and certain cyber-power interdependencies are listed as examples. [ABSTRACT FROM PUBLISHER]