• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2002년도 봄 학술발표회 논문집
• /
• pp.589-596
• /
• 2002

In this study, static pile load tests with load transfer measurement were accomplished in the field. Yield pile capacity (or ultimate pile capacity) determined by load-settlement-time relationship was determined and axial load transfer behavior was analyzed. In the test for the four test piles were behaved as end bearing pile but ratios of skin friction to total pile capacity were 27%∼33%.

• 한국위성정보통신학회논문지
• /
• 제6권2호
• /
• pp.91-96
• /
• 2011

본 논문에서는 물리적인 환경 변화에 의해 발생될 수 있는 갑작스런 부하단 임피던스의 변화를 정확히 측정할 수 있는 방법을 제시하였다. 부하단 임피던스 측정방법으로 ${\lambda}/4$ 전송선로(Sectioned Transmission Line) 상에서 측정된 전압을 이용하여 임의의 부하단 임피던스를 구하는 수식을 유도하였고, 계산된 수식의 결과 중 유효한 결과 만을 선택하는 부하단 임피던스 결정 알고리즘을 도출하였다. 제안된 임의의 부하단 임피던스 계산 수식과 부하단 임피던스 결정 알고리즘을 다양한 부하단이 적용된 시뮬레이션을 통해 검증하였고, 시뮬레이션 결과를 통해 임의로 설정한 부하단 임피던스를 정확하게 찾아 주는 것을 확인하였다.

• Journal of Electrical Engineering and Technology
• /
• 제1권2호
• /
• pp.161-169
• /
• 2006

Load representation has a significant impact on power system analysis and control results. In this paper, composite load models are developed based on on-line measurement data from a practical power system. Three types of static-dynamic load models are derived: general ZIP-induction motor model, Exponential-induction motor model and Z-induction motor model. For the dynamic induction motor model, two different third-order induction motor models are studied. The performances in modeling real and reactive power behaviors by composite load models are compared with other dynamic load models in terms of relative mismatch error. In addition, numerical consideration of ill-conditioned parameters is addressed based on trajectory sensitivity. Numerical studies indicate that the developed composite load models can accurately capture the dynamic behaviors of loads during disturbance.

• Journal of Electrical Engineering and Technology
• /
• 제7권5호
• /
• pp.653-658
• /
• 2012

Load modeling has a significant influence on power system analysis and control. In recent years, measurement-based load modeling has been widely practiced. In the load modeling algorithm, the model structure is determined and the parameters of the established model are estimated. For parameter estimation, least-squares optimization method is applied. The model parameters are estimated so that the error between the measured values and the predicted values is to be minimized. By introducing sliding window concept, on-line load modeling method can be performed which reflects the dynamic behaviors of loads in real-time. For the purpose of data acquisition, the measurement system including PMU is implemented in university level. In this paper, case studies are performed using real PMU data from Korea Univ. and Seoul National University of Science and Technology. The performances of modeling real and reactive power behaviors using exponential and ZIP load model are evaluated.

• 전기학회논문지
• /
• 제61권2호
• /
• pp.342-346
• /
• 2012

This paper presents a loop impedance(inner loop impedance & external impedance) measurement method in TN system. When the measurement of a loop impedance then the measurement result have a some error by load condition. In this paper suggest the loop impedance measurement on actual loading condition by two experiment. one was laboratory condition and the other was the actual measurement on site. Analysis result, measuring error by load condition has not effect on measuring loop impedance.

• Journal of Electrical Engineering and Technology
• /
• 제3권4호
• /
• pp.451-459
• /
• 2008

Accurate load modeling is essential for power system static and dynamic analysis. By the nature of the problem of parameter estimation for power system load modeling using actual measurements, multiple local optimal solutions may exist and local methods can be trapped in a local optimal solution giving possibly poor performance. In this paper, Trust-Tech, a novel methodology for global optimization, is applied to tackle the multiple local optimal solutions issue in measurement-based power system load modeling. Multiple sets of parameter values of a composite load model are obtained using Trust-Tech in a deterministic manner. Numerical studies indicate that Trust-Tech along with conventional local methods can be successfully applied to power system load model parameter estimation in measurement-based approaches.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2000년도 춘계학술대회 논문집
• /
• pp.652-659
• /
• 2000

The machine structure or parts has been arrive at a fracture, depend on crack by repeated load. Machine designer is estimate of fatigue strength in early stages the design for prevent fatigue fracture, then necessary its load history. This research study is using diesel locomotive in measurement of load history for fatigue design of rolling stock. The relation between velocity and amplitude of load history was found. We confirmed that the increase of velocity make to increase the magnitude of amplitude.

• 대한기계학회논문집A
• /
• 제30권5호
• /
• pp.560-567
• /
• 2006

The exact load measurements for the mechanical parts of a wind turbine are important step both fur the evaluation of a specific wind turbine design and for a certification process. A common method for a mechanical load measurement is using a strain gauge sensing. Two main problems ought to be answered in order for this method to be applied to the wind turbine project. These are strain gauge calibration and non-contact signal transmission from the strain gauge output to a load monitoring system. This paper suggests reliable solutions fer these two problems. A Bluetooth, a short range wireless data communication technology, is used to solve the second problem. The first one, the strain gauge calibration methodology for a load measurement in a wind turbine application, is fully explained in this paper. Various mechanical loadings for a strain gauge calibration in a wind turbine load measurement are introduced and analyzed. Initial experimental results which are obtained from a 1 kW small size wind turbine are analyzed, and the uncertainty problem in estimating mechanical loads using a calibration matrix is fully covered in this paper.

• 대한조선학회논문집
• /
• 제53권6호
• /
• pp.529-535
• /
• 2016

This study focuses on the comparison of measured data from 6-DOF motion sensor and strain gauge installed in the IBRV ARAON during 2015 summer voyage in the Arctic. Procedures to calculate the global ice load from MotionPak II inertial measurement system and the local load from stain gauge system are discussed. The ship's speed and peak load are determined in the concept of an ice collision "event". It is found that the peak values in the global ice calculated form whole ship motion analysis fall in the range of 1.5~3 times of the local ice load based in strain gauge measurement.

• 드라이브 ㆍ 컨트롤
• /
• 제18권2호
• /
• pp.38-45
• /
• 2021

In recent years, the demand for an onboard scale system which can directly monitor load distribution and overload of vehicles has increased. Depending on the suspension type of the vehicle, the onboard scale system could use different types of sensors, such as, angle sensors, pressure sensors, load cells, etc. In the case of a vehicle equipped with leaf spring suspension system, the load of the vehicle is measured by using the deflection or displacement of the leaf spring. Leaf springs have hysteresis characteristics that vary in displacement depending on the load state. These characteristics cause load measurement errors when moving or removing cargoes. Therefore, this study aimed at developing an onboard scale device for cargo vehicles equipped with leaf springs. A sectional modeling method which can reduce measurement errors caused by hysteresis characteristics was also proposed.