Sharif Digital Repository

Nowadays, the energy storage systems (ESSs) are widely used in different level of power systems for dealing with the challenges caused by the integration of renewable energy sources (RESs). Among the ESSs, batteries are more suitable for being used in microgrids (MGs) at distribution level due to their special features. Therefore, this paper presents a novel approach for planning of distributed battery energy storage systems (BESSs) to enhance MGs operation, economically. The model is formulated as a mixed integer nonlinear programming problem (MINLP) and considers various types of BESSs. In order to verify the effectiveness of the proposed approach, it is applied to the IEEE 33-bus network... 

The present context of the electric industry, characterized by competitive markets, privatization, and regulatory of technical requirements forces the power utilities to optimize their asset management practices and develop the requisite decision plans techno-economically. Practically approaching, this paper devises a new support tool based on a multiattribute decision making (MADM) framework in combination with analytical hierarchical process (AHP) to determine the most critical components of power transmission systems. Measure of system-wide reliability performance, outage cost, marginal clearing prices demonstrative of market fairness, and network losses are among the attributes... 

Deregulation of power system has introduced new objectives and requirements for transmission expansion problem. In this paper, a static transmission expansion methodology is presented using a multi-objective optimization framework. Investment cost, reliability (both adequacy and security), and congestion cost are considered in the optimization as three objectives. To overcome the difficulties in solving the nonconvex and mixed integer nature of the optimization problems, the genetic based NSGA II algorithm is used followed by a fuzzy decision making analysis to obtain the final optimal solution. The planning methodology has been demonstrated on the IEEE 24-bus test system to show the... 

In this paper, a new approach based on hybrid Particle Swarm-Based-Simulated Annealing Optimization technique (PSO-B-SA) is proposed for solving under-voltage load shedding (UVLS) problem. Under-voltage load shedding (UVLS) is one of the most important tools for avoiding voltage instability. In this paper, the UVLS problem is formulated based on the concept of the static voltage stability margin and its sensitivity at the maximum loading point or the collapse point. The voltage stability criterion is modeled directly into the load-shedding scheme. In any UVLS scheme finding the global point is very important for having cost effective economy. The proposed PSO-B-SA methodology is implemented... 

This paper presents a reliability-based approach to select appropriate wind turbine types for a wind farm considering site-specific wind speed patterns. An actual wind farm in the northern region of Iran with the wind speed registration of one year is studied in this paper. An analytic approach based on total probability theorem is utilized in this paper to model the probabilistic behavior of both turbines' availability and wind speed. Well-known probabilistic reliability indices such as loss of load expectation (LOLE), expected energy not supplied (EENS) and incremental peak load carrying capability (IPLCC) for wind power integration in the Roy Billinton Test System (RBTS) are examined. The... 

DG application has received increasing attention during recent years. The impact of DG on various aspects of distribution system operation, such as reliability and energy loss, depend highly on DG location in distribution feeder. Optimal DG placement is an important subject which has not been fully discussed yet. This paper presents an optimization method to determine optimal DG placement, based on a cost/worth analysis approach. This method considers technical and economical factors such as energy loss, load point reliability indices and DG costs, and particularly, portability of DG. The proposed method is applied to a test system and the impacts of different parameters such as load growth... 

Large-scale integration of wind power in the electricity system presents some planning and operational difficulties, which are mainly due to the intermittent and difficult nature of wind prediction process. Therefore it is considered as an unreliable energy source. This paper presents a new approach for solving the generation scheduling (GS) problem. It will consider the reserve requirement, load balance and wind power availability constraints. The particle swarm optimization (PSO) method is suggested to deal with the equality and inequality constraints in the GS problem. The proposed PSO is applied to a 12-unit test system (including 10 conventional thermal generating units and 2 wind... 

With high growth rate of demand for energy in different societies, the need for energy resources has been increased significantly. This has resulted in introduction of new energy resources, i. e. renewable energy resources in generation sector of energy systems. However, the intrinsic features of these energy resources call for higher flexibility in different sectors of energy systems. Flexibility in a comprehensive sense tries to cover the amount of imbalance between production and demand in energy systems. This paper has attempted to introduce the concept of operational flexibility in microgrids and it also has presented a step-by-step algorithm to assess this operational index based on a... 

In recent years, while energy consumption is still increasing, system peak load is decreasing due to deregulation in power systems, application of demand response programmes, microgrids and smart grids implementation, and so on. Thus, transmission system operators (TSOs), which are usually a public entity, must reinforce the transmission systems to maintain power system reliability. They are not interested in investing transmission network because of high investment costs. In this regard, this study presents a new bi-level model for co-planning of transmission system and merchant distributed energy resources (DERs). The upper level takes the TSOs perspective and aims to minimise the line... 

This paper provides a novel bad data detection processor to identify false data injection attacks (FDIAs) on the power system state estimation. The attackers are able to alter the result of the state estimation virtually intending to change the result of the state estimation without being detected by the bad data processors. However, using a specific configuration of an artificial neural network (ANN), named nonlinear autoregressive exogenous (NARX), can help to identify the injected bad data in state estimation. Considering the high correlation between power system measurements as well as state variables, the proposed neural network-based approach is feasible to detect any potential FDIAs.... 

This study presents a novel framework to incorporate the uncertainties associated with load fluctuations and components' availability in a day-ahead joint energy-reserve payment cost minimisation (PCM). The payments are calculated based on locational marginal prices (LMPs). Considering these uncertainties, appropriate definitions are not available for energy and reserve LMPs (RLMPs) that suit the probabilistic PCM formulation and reflect the market characteristics. A tri-level optimisation framework is proposed. The optimisation variables in the first-level optimisation include commitment status. In the second-level optimisation, the production schedule and allocated reserves are the... 

Secure operation of protective intelligent electronic devices (IEDs) has been recognized as a crucial issue for power grids. By gaining access to substation IEDs, intruders can severely disrupt the operation of protection systems. This paper develops an analytical reliability assessment framework for quantifying the impacts of the hypothesized integrity attacks against protection systems. Petri net models are used to simulate possible intrusion scenarios into substation networks. The cyber network model is constructed from firewall, intrusion prevention system (IPS), and password models, which are three types of defense mechanisms for protecting substation networks. In this paper, two main... 

This paper evaluates the reliability impact of UPFC application in power system. The paper proposes a new reliability model for the UPFC which is capable of considering different operating states of UPFC. The model is then applied to a test system to study the reliability impacts of UPFC. The impacts of operating points of different states of the model on the system reliability are analyzed. The role of model parameters in reliability impacts of UPFC is analyzed through the sensitivity analysis. A comparative study is finally conducted to illustrate the applicability of the proposed model compare to that of existing UPFC reliability models. The abilities and deficiencies of the proposed... 

In the new deregulated environment of electric power utility industry, new system reliability criteria and analytical tools are required. This paper proposes an analytical probabilistic model for reliability evaluation of competitive electricity markets. The market reliability is evaluated by using Markov state space diagram. Since the market is a continuously operated system, the concept of absorbing states is applied to it in order to evaluate the reliability. The market states are identified by using market performance indices and the transition rates are calculated by using historical data. To illustrate interesting feature of the proposed methodology, a case study is carried out over a... 

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... 

Considering the high level of interactions between energy and reserve markets, simultaneous clearing of these markets has been shown to provide more efficient solutions, than a sequential market clearing process. In addition, determining reserve requirements based on probabilistic approaches results in more economical efficiency, while maintaining an acceptable level of reliability, compared to deterministic approaches. This paper proposes a new method for clearing energy and spinning reserve markets simultaneously, while at the same time, spinning reserve requirements are determined based on a cost/benefit analysis as a probabilistic-based approach. This cost/benefit analysis considers both... 

This paper is concerned about the optimal placement of phasor measurement units (PMUs) so as to make a system completely observable. Observability assessment is done by the aid of the topological observability rules. Moreover a new rule is added which can decrease the number of required PMUs for complete system observability. A modified binary particle swarm is used as an optimization tool for obtaining the minimal number of PMUs and corresponding configuration. In order to improve the speed of convergence, an initial PMU placement is provided by graph-theoretic procedure. The simulation results of proposed approach are presented for several IEEE test systems  

The participants in auction-based electricity markets need to take part in a competition way, which operates, based on the concept of supply and demand theory to buy or sell the electricity. However, to have a feasible market solution, reactive power services are necessary to support the transmission of power from generation to end-users. This paper presents a methodology for optimal reactive power procurement, consistent with the auction-based electricity market mechanism. The proposed reactive power market is run in subsequence of the primary electricity market, allowing active power modification in light of available transmission capacity and reactive power resources. The IEEE 30-bus test... 

The deployment of flexible ac transmission system (FACTS) devices, despite miscellaneous benefits and applications, has been restricted mainly due to their large investment costs. Accordingly, the notion of distributed FACTS (D-FACTS) was recently proposed. Distributed static series compensators (DSSCs), as a new member of D-FACTS, are directly clamped to conductors of transmission lines. The possibility of controlling the compensation rate of DSSCs from the control center affords the active control of network power flow. This paper presents a comprehensive reliability model for the DSSC. The model is then reduced and a state-space representation is extracted for a transmission line with a... 

This paper discusses various aspects of unified power flow controller (UPFC) control modes and settings and evaluates their impacts on the power system reliability. UPFC is the most versatile flexible ac transmission system device ever applied to improve the power system operation and delivery. It can control various power system parameters, such as bus voltages and line flows. The impact of UPFC control modes and settings on the power system reliability has not been addressed sufficiently yet. A power injection model is used to represent UPFC and a comprehensive method is proposed to select the optimal UPFC control mode and settings. The proposed method applies the results of a contingency...