• Journal of Electrical Engineering and Technology
• /
• 제10권5호
• /
• pp.1921-1929
• /
• 2015

The smart substation is the heart of a transmission system, which is particularly emphasized as the most significant composition of smart grids in China. In order to assess the functionality performance of substation technologies, this paper presents methods used to identify the most promising solutions for smart substation design and to evaluate the technical levels of available technologies. The multi-index optimization model is presented to address the issue of smart substation planning. A mathematical model of the planning decision problem is established with multiple objectives consisting of economic, reliability, and green key indices, and many kinds of concerns including physical and environmentally friendly operations are formulated as a set of constraints. With respect to the assessment of the technical level regarding integration of advanced technologies into a substation, a modified grey whitenization weight function is adopted to structure a novel grey clustering method. The proposed grey clustering approach is used to overcome the difficulty of insufficient quantitative assessment capacity for traditional methods. The evaluation of technical effects provides the classification definition for the development phase and the maturity level of the smart substation. The effectiveness of the proposed approaches in planning decision-making and evaluation of construction efforts is demonstrated with case studies involving the actual smart substation projects of Wenchongkou substation in China Southern Power Grid (CSG) and Mengzi substation in State Grid Corporation of China (SGCC).

• 대한전기학회논문지:전력기술부문A
• /
• 제48권9호
• /
• pp.1103-1111
• /
• 1999

STACOM will be utilized to control substation voltage in the near future. Although STACOM shows good voltage regulation performance owing to its rapid and continuous response, it needs additional reactive power compensation device to keep control margin for emergency such as fault. ULTC transformer is one of good candidates. This paper presents a Kohonen Neural Network (KNN) based coordination control scheme of ULTC transformer and STACOM. In this paper, the objective function of the coordination control is minimization of both STACOM output and the number of switchings of ULTC transformer while maintaining substation voltage magnitude to the predefined constant value. This coordination, control is performed based on reactive load trend of the substation and KNN which offers optimal tap position in view of STACOM output minimization. The input variables of KNN are active and reactive power of the substation, current tap position, and current STACOM output. The KNN is trained by effective Iterative Condensed Nearest Neighbor (ICNN) rule. This coordination control applied to IEEE 14 bus system and shows satisfactory results.

• 조명전기설비학회논문지
• /
• 제29권9호
• /
• pp.59-64
• /
• 2015

IEC is an international standards which are used in many countries with Europe as the center. IEC standard is introduced in Korea according to WTO/TBT agreements, however until now there are no buildings in Korea which are designed applying IEC standard. Therefore, KEA(Korea Electric Association) is scheduled to construct Korean low voltage electrical installation integration test site which is designed applying IEC standard. In this paper, before being under construction of Korean low voltage electrical installation integration test site, power substation is modeled based on real design parameters and method to select circuit breakers and cables is presented applying IEC standard in the modeled power substation. EMTP(ElctroMagnetic Transient Program) is used for simulation program. EMTP which is power system analysis program is easy to model power system and power substation.

• 전기학회논문지
• /
• 제64권2호
• /
• pp.315-323
• /
• 2015

Nowadays, it is expected that mobility loads such as electric railways and electric vehicles will be penetrated gradually and affect on the power system stability by their load characteristics. Various researches have been carried out about electric vehicles for the recent decade though the load of electric railway could be forecasted because of the specified path and timetable, is a field with a long historic background. Some precise 5th polynomial equations are required to analyze the power system stability considering mobility load to be increased in the immediate future while the electric railway dispatching simulator uses load models with constant power and constant impedance for the system analysis. In this paper, seasonal urban railway load models are established as the form of 5th polynomial equations and substation load modeling methods are proposed merging railway station load models and general load models. Additionally, load management effects by the load modeling are confirmed through the case studies, in which seasonal load models are developed for Seoul Subway Line No. 2, Gyeongui Line and Airport Railroad and the substation load change is analyzed according to the railway load change.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
• /
• pp.92-94
• /
• 2000

This paper presents algorithm to plan construction and expanding of substation considering contingency accidents by proposing utilization factor according to configuration of substation bank system. In this paper, above all, proper sphere of supply area by each district which could be standardized with respect to its supply capacity is established under assumption of long term load forecasting which was made by district respectively, and then goal of utilization ratio based on configuration of substation bank was set to keep reliability by remaining sound bank when it happen to one bank accidents. Finally it is set up for optimal construction and expanding of substation considering economy and reliability simultaneously about substation to exceed these ratio.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2009년도 추계학술대회 논문집
• /
• pp.255-258
• /
• 2009

This paper gives a feasibility reference of integrating power automation for digital substation. An overview and techno-economical potential of IEC61850 are introduced. The result of economic analysis is shown to save up to one-third of the total cost of automation installation. The gained benefits can be used to increase the economy and reliability of electrical power system.

• Journal of Electrical Engineering and Technology
• /
• 제12권2호
• /
• pp.981-987
• /
• 2017

In this paper, we estimate the economic benefits of Energy Storage Systems (ESSs) for peak load shaving in an urban railway substation using the annual cost. The annual investment cost of ESSs is estimated using Net Present Value (NPV) and compared with the cost reduction of electricity by the ESS. The optimal capacities of the battery and Power Converting System (PCS) are determined for peak load shaving. The optimal capacity of the ESS and the peak load shaving is determined to maximize the profit by the ESS. The proposed method was applied to real load data in an urban railway substation, and the results show that electric power costs can be reduced. Other aspects of the ESS, such as the lifetime and unit price of the battery, are also investigated economically.

• 전기학회논문지
• /
• 제59권3호
• /
• pp.525-530
• /
• 2010

Installation of FACTS(Flexible AC Transmission System) device can maximize utilization of existing power facilities and reliability of power system. STATCOM has excellent characteristics in operating cost, maintaining facilities, loss and so on. However, STATCOM has a disadvantage of facility cost over capacity. So it is effective to coordinate STATCOM and existing external bank(capacitor and reactor) and OLTC(On Load Tap Changer). This paper mainly proposes coordinative control method between STATCOM installed within substation and other reactive power resources including Shunt Reactors and Shunt Capacitors and OLTC for voltage stability improvement. The proposed coordinative control method is developed for the STATCOM of Mi-gum substation and the simulation results of EMTP/RV model show the effectiveness of the proposed method.

• 전기학회논문지
• /
• 제63권12호
• /
• pp.1752-1758
• /
• 2014

This paper evaluates economic benefits of ESS (Energy Storage System) for peak load shaving in the substation of urban railway. For this purpose, the method to determine capacities of ESS and PCS (Power Conditioning System) for peak load shaving is proposed. Then the economic benefits of those devices are evaluated using net present value method. The proposed methods are applied to actual measurements of loads in the substation of urban railway. The results show that electric power costs can be reduced and the economic benefits of ESS for peak load shaving mainly depends on the price of battery.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 E
• /
• pp.2355-2357
• /
• 1999

Estimating equivalent soil model which represents an actual soil structure and its electrical characteristics, is extremely improtant for good substation grounding system design and analysis. Since the equivalent soil model is deduced based on the measured apparent soil resistivity - generally obtained from Wenner's 4-point method, reasonable and accurate measuring technique and procedure guarantee good grounding system design and analysis. The paper aims to show the importance of reasonable enough probe spacing by presenting the influence of soil modelling to estimation and measurement of grounding resistance of substation grounding grid.