Korean Electric Power Corporation Research Articles

Comparative Analysis of Estimated and Actual Power Self-Sufficiency Rates in Energy-Sharing Communities with Solar Power Systems

Amid the ongoing climate crisis, the international community is enacting policies to promote low-carbon energy-sharing communities. The primary objective of such communities is to enhance community-level energy self-sufficiency. Accurate energy self-sufficiency assessments are paramount in planning energy-efficient architectural designs, urban landscapes, and communal environments. In this study, the energy self-sufficiency rate of an energy-sharing community was estimated at the design stage and compared with the actual energy self-sufficiency rate calculated based on data collected over the following year (April 2022 to March 2023). The outcomes reveal that the estimated energy self-sufficiency rate is 171%, whereas the realized rate is 133%, underscoring the disparity between the projections and outcomes. An analysis of the seasonal variations in these discrepancies elucidated a correlation between the differences in the insolation levels between standard typical meteorological year (TMY) data that are conventionally used for energy generation projections and the actual meteorological conditions. Moreover, a notable incongruity surface exists between the monthly average electricity consumption of a standard four-person household, as stipulated by the Korean Electric Power Corporation (KEPCO) at 273 kWh, and the empirical power consumption at 430 kWh, resulting in a variance of approximately 157 kWh. This study illuminates the complex relationship between variables affecting energy self-sufficiency in energy-sharing communities. It serves as a crucial step towards informed decision making and precision in sustainable urban energy solutions.

Smart and Green Substation: Shaping the Electric Power Grid of Korea

The Korean Electric Power Corporation (KEPCO) has created a number of initiatives for encouraging both green and smart energy in the global energy industry. With the aim of being a smart energy creator, KEPCO conducted R&D for green and smart substations over the last 10 years, which will be implemented in future substations.

넷 제로에너지주택 실증사례 분석에 관한 연구

Purpose: This study analyzed and evaluated the NZEB (Net Zero Energy Building) on energy and cost based an electricity data from KEPCO (Korean Electric Power Corporation). Method: The experiment was conducted in three houses with different location and size. The experimental houses were constructed with high thermal insulation and air tightness, and also designed as all-electric houses where all the energy supplies (including heating and cooking) are made of electricity which reduces the maintenance cost and makes maintenance easier. 6kWp of Grid connected Photovoltaic System and air source heat pump for heating and hot water were applied to all houses, and one of them had an additional of solar domestic-hot water system with 5m² of collector. Result: For two years, all energy (including plug load, heating, cooling, lighting, how water supply and ventilation) was supplied by PV system and consequentially zero energy was achieved in two houses except A. Monthly electricity bill by the amount of used were not charged, however, additional fees by domestic electricity charging system were charged such as basic electricity fee, VAT on receiving electricity and development fund; average $123 were paid per household.

Operation Results and Utility of Dynamic Pricing Response Control-Applied VRF System in Summer Season

Dynamic pricing refers to a system in which a tariff varies, according to a level of charging and applied time depending on time change. The power billing system used in the Korean Electric Power Corporation (KEPCO) is based on time of use (TOU) pricing, which is one of the dynamic pricing systems. This paper aimed to determine the operational results of a variable refrigerant flow system, to which a new control algorithm was applied, in order to respond to dynamic pricing, in summer and the utility of the new control. To do this, real measured data was acquired from a VRF system installed in a building for educational purposes, where dynamic pricing was applied for about 100 days during summer time. At the maximum load operation time period in TOU, the new control minimized operation within the indoor comfort range, an increase in refrigerant evaporation temperature in the indoor unit and the number of revolutions in a compressor in the outdoor unit was limited. As a result, power usage was decreased by 11%, and the operational cost by 14.6%. Furthermore, measurement results using the Predicted Mean Vote (PMV) model, that represented satisfaction of thermal environment, showed that 82.8% to 90.4% of the occupants of the building were satisfied during operation when the new control was applied.

Voltage Stability Index for Distribution Network connected in Loop Configuration

ABSTRACTIn power distribution networks, voltage instability can lead to voltage collapse and thus power blackout. A considerable amount of research has been carried out on voltage stability analysis of transmission and radial distribution networks. However, voltage stability analysis considering loop nature of distribution network is largely unaddressed. In this paper, a simplistic analytical approach is proposed, based on circuit analysis and famous biquadratic method to evaluate voltage stability of loop distribution networks in terms of voltage stability index (VSI). This work derives mathematical expressions for VSI of loop configuration for two realistic cases. The performance of proposed VSI is initially evaluated for Korean Electric Power Corporation distribution network. Benchmark analysis has been conducted on IEEE 69 bus test distribution networks to demonstrate the validity of the proposed approach in comparison with relevant works. The proposed approach is also applied for distributed generation placement and faults identification analysis. The results demonstrate the performance improvement in VSI of loop-based distribution networks which are expected to be useful for practical applications of future smart grids.

Comparison between Underground Cable and Overhead Line for a Low-Voltage Direct Current Distribution Network Serving Communication Repeater

This paper compares the differences in economic feasibility and dynamic characteristics between underground (U/G) cable and overhead (O/H) line for low-voltage direct current (LVDC) distribution. Numerous low loaded long-distance distribution networks served by medium-voltage alternative current (MVAC) distribution lines exist in the Korean distribution network. This is an unavoidable choice to compensate voltage drop, therefore, excessive cost is expended for the amount of electrical power load. The Korean Electric Power Corporation (KEPCO) is consequently seeking a solution to replace the MVAC distribution line with a LVDC distribution line, reducing costs and providing better quality direct current (DC) electricity. A LVDC distribution network can be installed with U/G cables or O/H lines. In this paper, a realistic MVAC distribution network in a mountainous area was selected as the target model to replace with LVDC. A 30 year net present value (NPV) analysis of the economic feasibility was conducted to compare the cost of the two types of distribution line. A simulation study compared the results of the DC line fault with the power system computer aided design/electro-magnetic transient direct current (PSCAD/EMTDC). The economic feasibility evaluation and simulation study results will be used to select the applicable type of LVDC distribution network.

Visualization of Dynamic Simulation Data for Power System Stability Assessment

Power system analyses, which involve the handling of massive data volumes, necessitate the use of effective visualization methods to facilitate analysis and assist the user in obtaining a clear understanding of the present state of the system. This paper introduces an interface that compensates for the limitations of the visualization modules of dynamic security assessment tools, such as PSS/e and TSAT, for power system variables including generator rotor angle and frequency. The compensation is made possible through the automatic provision of dynamic simulation data in visualized and tabular form for better data intuition, thereby considerably reducing the redundant manual operation and time required for data analysis. The interface also determines whether the generators are stable through a generator instability algorithm that scans simulation data and checks for an increase in swing or divergence. The proposed visualization methods are applied to the dynamic simulation results for contingencies in the Korean Electric Power Corporation system, and have been tested by power system researchers to verify the effectiveness of the data visualization interface.

Determination of Critical Generator Group Using Accelerating Power and Synchronizing Power Coefficient in the Transient Energy Function Method

This paper proposes an algorithm for determining critical generator lists using accelerating power and synchronizing power coefficient (SPC), and critical generator group (CGG) from CGG candidates, which is a combination of critical generators. The accurate determination of CGG provides a more accurate energy margin while providing system operator with information of possible unstable generator group. Classical transient energy function (TEF) method selects the critical generators with big corrected kinetic energy of each generator at the moment of fault removal. However, the generator with small acceleration after fault, that is, the generator with small corrected kinetic energy, is also likely to belong to CGG if the generator has small synchronizing power. The proposed algorithm has been verified to be effective compared with the classical TEF method. We utilized the power system of Korean Electric Power Corporation(KEPCO) as a test system.

A Study on the Assignment of the Vibration Classes to the Power Transformers in Operation (154[kV

High reliability is essential for power transformers, and their fault causes are reportedly more related to mechanical causes than electrical ones. The transformer soundness judgment currently depends only on the electrical insulation characteristic and the chemical test of the insulation oil, so that there are few fundamental measures against the frequent mechanical damages and failures in transformers.<BR> The mechanical soundness judgment techniques are conducted through processes that include structural analysis and vibration resistance treatment during the manufacturing process of each manufacturer, but the vibration is not tested during the design, manufacturing, and operating processes since there are no detailed technical standards and procedures on the vibration problem, which are important in terms of maintenance.<BR> Therefore, in this study, vibration phenomena were measured from the 32 power transformers in operation in the substations under the Daejeon Power Transmission District Office of the Korean Electric Power Corporation (KEPCO). The vibration was measured at 24 sections (6x4) on one side, and only the maximum values were selected from the measured vibration values. This was because the maximum vibration values more significantly affect the soundness of the transformer than the average vibration values. The vibration classes were given considering the maximum vibration based on ISO 10816-1 (2001).