Sharif Digital Repository

Remote controlled switches (RCSs) have the ability to isolate the faulted area from other parts of the distribution system. On the other hand, the dispatchable distributed generators (DDGs) and tie lines can supply the interrupted loads after fault occurrence trough microgrids and reduce the outage time. In this regard, this article proposes a planning model for simultaneous placement of RCSs, DDGs, and tie lines to improve distribution system reliability. The presence of renewable distributed generations (RDGs) and energy storage systems, which have an increasing penetration in today's distribution networks are also considered. Moreover, two different practical load shedding methods are... 

In power distribution systems, sometimes, system reliability indices are available, where some components' reliability parameters are unknown. This letter presents the inverse reliability evaluation (IRE) problem in radial distribution systems to find unknown components' parameters from the known system reliability indices. To this end, a nonlinear system of equations is presented and solved. The solutions are analyzed in the RBTS bus 2 to verify the applicability of the proposed approach and to show the importance of the IRE problem. © 1969-2012 IEEE  

Remote control switches (RCSs) are often assumed to be fully reliable in reliability and cost/worth analyses. This assumption, however, overestimates their merits, thereby misguiding network owners about their optimal implementation. This letter extends the current reliability evaluation procedure to incorporate probability of RCS malfunctions. Then, the extended procedure is applied to a network equipped with a few RCSs. The numerical studies reveal that RCS malfunctions degrade their worth, which may even affect their optimal number and locations. © 1969-2012 IEEE  

Supervisory control and data acquisition (SCADA) infrastructures have so far been brought into the huge amount of focus since the need for a more reliable power system accosting with the catastrophic events of interruptions has been raised. Hence, benefiting from an automation technology which can remotely monitor and coordinate commands to enable immediate response and switching are obviously inevitable. This paper outlines an implementable method in response to the goal of placement of remote terminal units (RTUs) which are in charge for data acquisition and control in a power distribution system. In this light, a new practical methodology based on the robust decision making (DM) method,... 

One of the most important issues in the smart grid is to quantitatively assess the impacts of distributed energy resources (DER) on the distribution system reliability. Solar cells (SCs) as developing DERs are normally placed close to the load centers. In this paper, a new algorithm is developed to evaluate distribution system reliability, considering SCs in the vicinity of the end-users. The probabilistic nature of the demand and SC power output are investigated to solve challenges of integrating these intermittent resources with the distribution system. In a smart home, to handle the variation of SC generation, solar load controller (SLC) is utilized to match load and generation of SCs... 

Design and development of fault diagnosis schemes (FDS) for electric power distribution systems are major steps in realizing the self-healing function of a smart distribution grid. The application of the FDS in the electric power distribution systems is mainly aimed at precise detecting and locating of the deteriorated components, thereby enhancing the quality and reliability of the electric power delivered to the customers. The impacts of two types of the FDS on distribution system reliability are compared and presented in this paper. The first type is a representative of the FDS which diagnoses the deteriorated components after their failing. However, the second type is a representative of... 

Design and development of fault diagnosis schemes (FDS) for electric power distribution systems are major steps in realizing the self-healing function of a smart distribution grid. The application of the FDS in the electric power distribution systems is mainly aimed at precise detecting and locating of the deteriorated components, thereby enhancing the quality and reliability of the electric power delivered to the customers. The impacts of two types of the FDS on distribution system reliability are compared and presented in this paper. The first type is a representative of the FDS which diagnoses the deteriorated components after their failing. However, the second type is a representative of... 

Distribution automation application for fault management in the electricity distribution networks is one of the main potential remedial actions to reduce customers' outage times and hence improve service reliability. For this purpose, various automation schemes have been developed and introduced in different countries and by different venders. However, the challenge for electric utilities, especially in today's competitive electricity market, is to identify and evaluate potential reliability reinforcement schemes. Accordingly, appropriate schemes must be determined and prioritized for implementation. In this context, reliability cost/worth assessment plays an important role. A comprehensive... 

Implementation of Distribution Automation (DA) in electric power distribution systems can result in customer satisfaction with improved reliability, consistent quality and high-tech services. Loop Restoration Strategy (LRS) is a special DA method in the feeder level which is used by electric utilities to improve distribution system reliability. The effects of the implemented LRS on the reliability indices of a given distribution system mainly depend on its Automatic Control System (ACS). Selecting the type of ACS of LRS by electric utilities relies on the level of improvement required at load points and system oriented reliability indices. A step by step evaluation procedure is proposed in... 

Loop restoration scheme (LRS) is a special feeder automation (FA) scheme, which is used by utilities to improve distribution system reliability. The LRS is controlled and managed by its automatic control system (ACS). The impacts on distribution system reliability indices of implementing LRS mainly depend on the type of its ACS. Two common types of ACS of LRS are presented and used in this study. Successful operation of ACS is dependent on the protection and automatic control functions of switching devices of LRS. Different failure modes of these switching devices can therefore affect the procedure of ACS in fault detecting, isolating and service restoration. The impacts of failure of... 

In this paper, a new method for designing procedure of Reward-Penalty Scheme (RPS) in distribution system is proposed. Being fair and adoptable in viewpoint of distribution companies (DisCos) are main superiorities of the proposed RPS. Established based on concept of the Yardstick theory, its application can ensure regulators that a perfect competition will be created between DisCos to improve the service reliability. Also, such a regulation scheme can be a key for power system decision makers in order to prevent the DisCos from decreasing service reliability. Aimed to reach a fair mechanism, the proposed RPS rewards/penalizes the DisCos only compared with the other ones owning similar... 

Continuity of supply plays a significant role in modern distribution system planning and operational studies. Accordingly, various techniques have been developed for reliability assessment of distribution networks. However, owing to the complexities and restrictions of these methods, many researchers have resorted to several heuristic optimization algorithms for solving reliability-constrained optimization problems. Therefore, solution quality and convergence to global optimality cannot be guaranteed. Aiming to address this issue, two salient mathematical models are introduced in this paper for topology-variable-based reliability evaluation of both radial and radially-operated meshed... 

Standard mathematical-programming-based models have attracted considerable attention for optimizing distribution system planning and operation due to their salient advantages. More specifically, mixed-integer linear programming (MILP) has proven very effective in modeling such problems. The availability of optimization software for efficiently solving MILP problems with guaranteed convergence to optimality while providing a measure of the distance to the optimal solution has made MILP models more popular. Although a plethora of efficient MILP formulations have been proposed for planning and operating studies of distribution grids, incorporating reliability into such models is still... 

Reliability assessment is of primary importance in designing and planning distribution systems that operate in an economical manner with minimal interruption of customer loads. Distributed generation (DG) is expected to play an increasing role in emerging power systems because they use different type of resources and technologies to serve energy to power systems. DG is expected to improve the system reliability as its backup generation. Since DG units are subject to failures as all other generation units, the random behavior of these units must be taken into account in the analysis. Existence of DG units in a distribution system will effect on restoration time of load points. In this paper,... 

This paper presents a reliability assessment algorithm for distribution systems using a Static Series Voltage Regulator (SSVR). Furthermore, this algorithm considers the effects of Distributed Generation (DG) units, alternative sources, system reconfiguration, load shedding and load adding on distribution system reliability indices. In this algorithm, load points are classified into 8 types and separated restoration times are considered for each class. Comparative studies are conducted to investigate the impacts of DG and alternative source unavailability on the distribution system reliability. For reliability assessment, the customer-oriented reliability indices such as SAIFI, SAIDI, CAIDI... 

This paper presents a novel profit-based model for multistage distribution network expansion planning. In the proposed model, some capabilities of the distribution automation system are considered to achieve a plan that is more compatible with the strategic plan towards a smart distribution grid. Moreover, a method for reliability evaluation of a distribution network in the planning studies is proposed. The objective function of the planning problem is the net present value of the company's profit. The problem is solved by employing the genetic algorithm approach as a promising technique in solving the mixed-integer nonlinear programming problem. The proposed method is evaluated on an... 

Implementing automation system in distribution networks needs a huge investment that usually cannot be funded entirely in a short period of time. So distribution companies (DISCOs) should develop long-term plans to equip their network with automation technologies as far as economically justifiable. Aiming to provide a methodology for development such plans, this paper presents a novel multistage planning model for implementing distribution automation system considering all main hardware and software infrastructures. The proposed method optimally determines the type, location, and time in which an equipment or infrastructure must be added to network considering the network capacity expansion...