• Journal of Power Electronics
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• 제19권5호
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• pp.1289-1302
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• 2019

In this paper, an optimal allocation method of a hybrid active power filter in an active distribution network is designed based on the differential evolution algorithm to resolve the harmonic generation problem when a distributed generation system is connected to the grid. A distributed generation system model in the calculation of power flow is established. An improved back/forward sweep algorithm and a decoupling algorithm are proposed for fundamental power flow and harmonic power flow. On this basis, a multi-objective optimization allocation model of the location and capacity of a hybrid filter in an active distribution network is built, and an optimal allocation scheme of the hybrid active power filter based on the differential evolution algorithm is proposed. To verify the effect of the harmonic suppression of the designed scheme, simulation analysis in an IEEE-33 nodes model and an experimental analysis on a test platform of a microgrid are adopted.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권12호
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• pp.704-713
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• 2002

This paper describes operational characteristics of wind turbine induction generators interconnected with distribution networks using PSCAD/EMTDC. Due to the simple and durable structure, induction generators are the most common type used in wind Power generation. Generally, induction generators are classified into two groups according to the shape of rotor, one is squirrel-cage type and the other is wound-rotor type. In this study, we simulate the start-up and the output variation of generators interconnected with distribution networks and compare the operational characteristics of squirrel -cage type and wound-rotor type induction generators located in the unfaulted distribution lines about the disturbance occurred on the associated distribution feeders emanated from the substation to which wind turbine generator is connected. In order to obtain the realistic results, we use the radial distribution network of IEEE 13-bus model.

• Journal of information and communication convergence engineering
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• 제19권4호
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• pp.205-213
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• 2021

The properties of a scale-free network are little known; its node degree following a power-law distribution is among its few known properties. By selecting real-field scale-free networks from a network dataset and comparing them to other networks, such as random and non-scale-free networks, the topology characteristics of scale-free networks are identified. The assortative coefficient is identified as a key metric of a scale-free network. It is also identified that most scale-free networks have negative assortative coefficients. Traditional generation models of scale-free networks are evaluated based on the identified topology characteristics. Most representative models, such as BA and Holme&Kim, are not effective in generating real-field scale-free networks. A link-rewiring method is suggested that can control the assortative coefficient while preserving the node degree sequence. Our analysis reveals that it is possible to effectively reproduce the assortative coefficients of real-field scale-free networks through link-rewiring.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권6호
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• pp.2518-2533
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• 2020

In wireless sensor networks, adversaries may physically capture sensor nodes on the fields, and use them to launch false positive attacks (FPAs). FPAs could be conducted by injecting forged or old sensing reports, which would represent non-existent events on the fields, with the goal of disorientating the base stations and/or reducing the limited energy resources of sensor nodes on the fields. Researchers have proposed various mitigation methods against FPAs, including the statistical en-route filtering scheme (SEF). Most of these methods are based on key pre-distribution schemes and can efficiently filter injected false reports out at relay nodes through the verification of in-transit reports using the pre-distributed keys. However, their filtering power may decrease as time goes by since adversaries would attempt to capture additional nodes as many as possible. In this paper, we propose an adaptive key distribution method that could maintain the security power of SEF in WSNs under such circumstances. The proposed method makes, if necessary, BS update or re-distribute keys, which are used to endorse and verify reports, with the consideration of the filtering power and energy efficiency. Our experimental results show that the proposed method is more effective, compared to SEF, against FPAs in terms of security level and energy saving.

• 대한전기학회논문지:전력기술부문A
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• 제48권9호
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• pp.1073-1080
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• 1999

Optimal routing of distribution networks can be attained by keeping the line power capacity limit to handle load requirements, acceptable voltage at customer loads, and the reliability indices such as SAIFI, SAIDI, CAIDI, and ASAI limits. This method is composed of optimal loss reduction and optimal reliability cost reduction. The former is solved relating to the conductor resistance of all alternative routes, and the latter is solved relating to the failure rate and duration of each alternative route. The routing considering optimal loss only and both optimal loss and optimal reliability cost are compared in this paper. The case studies with 10 and 24 bus distribution networks showed that reliability cost should be considered as well as loss reduction to achieve the optimal routing in the distribution networks.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1043-1050
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• 2014

Obsolescent control systems for power systems are evolving into intelligent systems and connecting with smart devices to give intelligence to the power systems. As networks of the control system are growing, vulnerability is also increasing. The communication network of distribution areas in the power system connects closely to vulnerable environments. Many cyber-attacks have been founded in the power system, and they could be more critical as the power system becomes more intelligent. From these environment, new communication network architecture and mitigation method against cyber-attacks are needed. Availability and Fault Tree analysis used to show that the proposed system enhances performance of current control systems.

• Structural Engineering and Mechanics
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• 제58권1호
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• pp.21-38
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• 2016

Many studies have been carried out to investigate the important factors in calculating the realistic entropy amount of water distribution networks, but none of them have considered both mechanical and hydraulic characteristics of the networks. Also, the entropy difference in various networks has not been calculated exactly. Therefore, this study suggested a modified entropy function to calculate the informational entropy of water distribution networks so that the order of demand nodes and entropy difference among various networks could be calculated by taking into account both mechanical and hydraulic characteristics of the network. This modification was performed through defining a coefficient in the entropy function as the amount of outflow at each node to all dissipated power in the network. Hence, a more realistic method for calculating entropy was presented by considering both mechanical and hydraulic characteristics of network while keeping simplicity. The efficiency of the suggested method was evaluated by calculating the entropy of some sample water networks using the modified function.

• Transactions on Electrical and Electronic Materials
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• 제18권2호
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• pp.111-118
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• 2017

The increased diversity of different types of energy sources requires moving towards smart distribution networks. This paper proposes a probabilistic DG (distributed generation) units planning model to determine technology type, capacity and location of DG units while simultaneously allocating ESS (energy storage systems) based on pre-determined capacities. This problem is studied in a wind integrated power system considering loads, prices and wind power generation uncertainties. A suitable method for DG unit planning will reduce costs and improve reliability concerns. Objective function is a cost function that minimizes DG investment and operational cost, purchased energy costs from upstream networks, the defined cost to reliability index, energy losses and the investment and degradation costs of ESS. Electrical load is a time variable and the model simulates a typical radial network successfully. The proposed model was solved using the DICOPT solver under GAMS optimization software.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.299-301
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• 2003

In this paper, a protection system using Multi-Agent concept for power distribution network is proposed. Multi agent system consist of Feeder agent, OCR(Over Current Relay) agent, Recloser agent and Switch agent. An agent calculates and corrects its parameter by itself through communication with neighboring agents and its own intelligence algorithm. Simulations in a simple distribution network show the effectiveness of the suggested protection system. Multi-Agent System, protection of distribution network, Communication.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3015-3017
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• 1999

KEPCO is faced with a number of network choice for Distribution Automation System(DAS), such as Power Line, Pair. Coaxial and Optical Cable, etc. The increasing use of DAS requires suitable communication networks. KEPCO has exhausted much efforts to implement its own standard DAS in possible early date. This paper presents the DAS in KEPCO and some of initial design efforts toward KEPCO's DAS at KEPRI.