윤용태 교수

AbstractThis article investigates and compares various types of microgrids in the literature. The comparison is concerned with the economic operation of the micro-sources employed in different topologies and the reliability of the end-users. Also, the effect of each component on the performance of the overall microgrid is discussed in detail, e.g., the individual and centralized power converters, etc. The numerical simulation of a case study shows that the single AC and three wire network microg

A microgrid is a group of many small-scale distributed energy resources, such as solar/wind energy sources, diesel generators, energy storage units, and electric loads. As a small-scale power grid, it can be operated independently or within an existing power grid(s). The microgrid energy management system is a system that controls these components to achieve optimized operation in terms of price by reducing costs and maximizing efficiency in energy consumption. A post-Industry-4.0 consumer requi

The sizable electrical load of plug-in electric vehicles may cause a severe low-voltage problem in a distribution network. The voltage drop in a distribution network can be mitigated by limiting the power consumption of a charging station. Then, the charging station operator needs a method for appropriately distributing the restricted power to all plug-in electric vehicles. The existing approaches have practical limitation in terms of the availability of future information and the execution time

SUMMARY The problem of distribution system maintenance has a combinatorial explosion of choices. It may not be worthwhile to solve this problem using the analytical method that require too much time and cost. Ordinal optimization is a prime candidate of stochastic optimization problem. Ordinal optimization is used to quickly narrow the search space and find a good enough solution with reasonable confidence. This paper proposes the reliability centered maintenance model of distribution systems, a

Determination of the required reserve capacity has an important function in operation of power system and it is calculated based on the largest loss of supply. However, conventional method cannot be applied in future power system, because potential grid-connected distributed generator and abnormal temperature cause the large load imbalance. Therefore this paper address new framework for determining the optimal required reserve capacity taking into account the real time load imbalance. At first,

Abstract A reliable electricity supply infrastructure is fundamental to modern living. An interruption to electricity services has such far reaching impact to our everyday lives to various industries compared to other service interruptions, thus to build in significant redundancy and various preventive measures to electric power system operation and planning is needed. Just as important as to incorporate redundancy and preventive measures however, an effective restoration plan needs to be in pla

This paper proposes a new approach to distribution system named Three-wire Network (3-NET). Considering the integration of different distributed generation (DG) technologies as well as the diversity of loads, the idea of 3-NET is splitting a single power network into three qualitatively different networks: (i) a high quality direct current (DC) network; (ii) a conventional alternating current (AC) network; and (iii) a low quality DC network. By this configuration, the multi-stage conversion of e

Abstract The purpose of this paper is to examine the economic and technical perspectives of dynamically administered critical peak pricing (DA‐CPP) program as an active demand response (DR) program. To implement a good DR program, there are three perspectives to be considered: regulatory, economic, and technical perspectives. We propose a special DA‐CPP program as an effective DR program, which is administered by an energy service provider (ESP). ESP has control on when to call critical peaks on

This chapter deals with transmission expansion. Following development of the energy market, the transmission provider transforms into the independent transmission company (ITC) so as to admit a highly sophisticated market. Since the transmission grid is a physical system, the ITC is able to execute bilateral contracts as far as the system design and operating conditions permit. Consumers can establish various service contracts with any supplier in order to obtain the lowest rate and most desirab

The paper describes a practical approach to implementing the congestion cluster pricing method as a viable congestion management system (CMS) in the operation of electric power systems. The congestion cluster pricing method is formulated as a stochastic optimization problem of the cluster design. In the formulation the performance of the pricing method is introduced as a measurable function of cluster design, based on the conceptual criteria necessary for an effective CMS. We define the search s

Abstract In a liberalized power industry, key information used to determine how much can be transferred through the network is known as total transfer capability (TTC). Without considering the uncertain nature of power systems, we would be even skeptical whether TTC is actually meaningful in practice. This paper primarily purports to determine TTC based on the fuzzy set theory for continuation power flow (CPF), thereby capturing uncertainty. Given that uncertainties in the TTC calculation are es

There are several types of load in distribution system. The load value that represents the varying load with time is needed to be estimated for reconfiguration because the system is reconfigured in non-real time. Specially, as the power system develops as the smart grid, the amount of distributed generations is increased. Since the variability of distributed generations’ output is higher compared to normal generations, it is important that which representative value is used for variable output w

In this paper we describe a fundamental structure for the transmission provider (TP) composed of the independent transmission company (ITC) and the system operator (SO). Under the proposed structure, the ITC and the SO are two entities working cooperatively to carry out the functions of the TP. The entities are di erentiated through the ownership and the operational authority. Roughly speaking, the ITC owns the regional network, provides various services connected with the longer term (physical

Future power systems are expected to have distributed energy resources (DERs). A price-based operation (PBO), where dynamic prices are used as the control signal, can be an alternative scheme to address challenging operational issues in the future power systems. In this paper, a decentralized framework for optimal PBO using a feedback control mechanism is proposed to determine the nodal prices for power balance and congestion management. The substructures and feedback controllers of the proposed