• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.2
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• pp.59-64
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• 1983

This paper deals with the transient energy method of transient stability analysis of multi-machine power system by improving the transfer conductance, the kinetic energy and the critical transient energy. The tranfer conductance is considered more correctly, the generators of system are seperated to two states (critical and the rest state)and the correction term of critical transient energy (to reference point) is added. This analysis is performed by digital computer simulation and the application of this method to two model systems has shown its superiority to other available methods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.354-362
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• 2008

This paper presents the new method of power system transient stability simulation, which combines the desirable features of both the time domain technique based on OOP(Object-oriented Programming) and the direct method of transient stability analysis using detailed generator model. OOP is an alternative to overcome the problems associated with the development, maintenance and update of large software by electrical utilities. Several papers have already evaluated this approach for power system applications in areas such as load flow, security assessment and graphical interface. This paper applied the object-oriented approach to the problem of power system dynamics simulation. The modeling method is that each block of dynamic system block diagram is implemented as an object and connected each other. In the transient energy method, the detailed synchronous generator model is so-called two-axis model. For the excitation model, IEEE type1 model is used. The developed mothed was successfully applied to New England Test System.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.21-25
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• 2010

This paper explains hybrid method that combines Time domain simulation technique with the direct method of Transient stability analysis. First, it calculate trajectory of real system by Time domain Simulation using OOP(Object Oriented Programming method) and evaluate Transient Energy Function to induce stability index to calculate Transient stability margin. Once the status of system(stable or unstable) has been identified, proper criteria are proposed to stop time-domain simulation to reduce CPU time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4494-4499
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• 2014

The margin of transient stability of a weak grid system is very low because of the small short-circuit ratio and large impedance. If the fault of the weak grid is cleared by the protection system, one of the major lines is disconnected after the fault is cleared. This further reduces the system strength. Therefore, it is necessary that a new generation system be added to the weak grid to enhance the transient stability margin. A conventional synchronous generator and wind turbine generator were added to a base grid system. The results of transient stability analysis with additional generators using PSSE were compared. The simulations showed that wind turbine generators provide good damping performance and enhance the transient stability margin based on CCT up to 5 times.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.594-600
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• 2006

In this study, transient and quasi-static analysis were done for the evaluation of structural integrity of the platform screen door due to train wind pressure. Fluent 6.0 was used to calculate the train wind pressure, and Ansys 10.0 was used to evaluate the structural stability of platform screen door due to train wind pressure. Transient analysis was used to check the design requirements of platform screen door, and quasi-static analysis was introduced to save the calculating time and check quickly structural performances when compared to those of transient analysis. The results show that structural stability of the platform screen door under train wind pressure is proven and quasi-static analysis can quickly check the structural integrity of platform screen door.

• 전기의세계
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• v.15 no.1
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• pp.14-19
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• 1966

Transient stability analysis of Yongwol-Bupyong power system, which contains Yongwol steam power station, the largest one in Korea, was undertaken by using the Yonsei 101 Analog computer. The critical switching time and phase angle for the present 150MW power flow to be stable were found. And the transient stability power limit for the system was also found. It is concluded that the system becoms unstable if the power flow increases much more than 151MW.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.421-430
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• 1991

This paper investigated the errect of the right-half-plane zero on stability in the buck-boost DC-DC converter which is one type of the switching regulator and the stability region for the variation of the output current is obtained by evaluating the feedback gain. And it is clarified that the damping ratio decreases gradually by increase of the feedback loop gain and the regulation system of the converter becomes unstable, and from the transient response analysis we obtainedthe stability region about this converter. From above result it is known that the stability decreases by the existence of the right-half-plane zero. For the improvement of stability, we carried out one pole compensation in feedback circuit and obtained the avaliable stability region in relation to the gain bandwidth product from the stability and transient response analysis. These results were established experiment.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1119-1124
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• 2014

This paper describes the emergency situation which occurs in Drilling Rig power system. Especially, we focused on power system transient characteristics on propulsion motor load and generator elimination situation in Drilling Rig operation. We performed numerical simulation and analyzed the result for power system transient stability characteristics on each condition for excitation system and governor control system using ETAP (Electrical Transient Analysis Program).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.1-8
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• 2016

The characteristics of Korean power systems are large capacity of generation sites and concentrated load in Seoul metropolitan area. According to the national generation facility plan, more generation facilities are needed to be constructed as the electrical demands are forecasted to increase. Moreover, the size of generation sites are expected to increase, too. Therefore transient stability problems become worse and worse. Recently, the necessity of HVDC has been raised to overcome the difficulty of constructing HVAC transmission lines. This paper shows the analysis of transient stability when HVDC transmission system is added to the power system consisting of large generation sites.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.736-740
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• 2004

In order to overcome the problems of simulation methods, the power system transient stability assessment method using critical fault clearing time functions has been developed. Using the above method, this paper has developed the new method which can assess accurately and efficiently the effects of control and protection systems on transient stability which is the most important characteristic to assess in power systems. At first, critical fault clearing time functions CCT(W:load) are defined by taking notice of the fact that transient stability is mainly controlled by fault clearing time and load. Next, the method to be enable to assess accurately and efficiently the effects of control and protection systems on transient stability has been newly developed by using the above functions. Finally, it has been applied to the effect assessment in the occurrence of a three-phase fault in a model power system. Results of application have been clarified its effectiveness.