• Journal of Electrical Engineering and Technology
• /
• v.5 no.2
• /
• pp.191-196
• /
• 2010

Power system restoration following a massive or complete blackout starts with energizing the primary restorative transmission system. During this primary restoration process, unexpected overvoltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. In the case of the Myanmar electric power system, there are so many wide outage experiences, including complete blackout cases, caused by 230kV line faults and so on. Consequently, Myanmar's system operators have been well trained to deal with wide blackouts. Howver, system blackout restoration has been conducted by relying on the experience of only a few specialists. So, more scientific analysis is required to meet the requirements necessary to ensure fast and reliable system restoration. This paper presents analytical results on the primary restorative transmission system of Myanmar, focusing on the problems during the early restoration process. Methodologies are presented that handle load pick-up, terminal voltage and the reactive capability limitation of black-start generators to compensate the Ferranti effect. Static and dynamic simulation with the PSSolution and EMTDC programs respectively for the six cases are performed in order to select the primary restorative transmission lines.

• Proceedings of the KIEE Conference
• /
• 2004.11b
• /
• pp.249-251
• /
• 2004

Harmonic resonant overvoltage during restoration of primary restorative transmission system originates in switching operations and nonlinear characteristics of equipments. Actually it is difficult to predict the occurrence of harmonic overvoltage, since they result from nonlinear characteristics of transformers and other equipments. This paper describes the analysis of domestic primary restorative transmission system using PSCAD/EMTDC. The harmonic resonance is verified and showed the relation with equipments which have nonlinear characteristics such as generator and transformer in this paper. And the solution to prevent harmonic resonance is proposed too. As a result, the PSCAD/EMTDC simulation showed slightly conflictive results that had been presented by IEEE Power System Restoration Working Group report.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.2
• /
• pp.262-266
• /
• 2010

During the restoration process of primary restorative transmission system, the over voltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. This over voltage is caused by harmonic resonance and can be prevented by damping loads that are connected before restoration process of primary restorative transmission system. But it is very difficult to predict the occurrence possibility of the harmonic resonance previously. This paper analyzes the relationship between the harmonic resonance and the amount of damping loads to prevent the harmonic resonance. This paper calculates the minimum amount of damping loads to prevent harmonic resonance while changing the length of primary restorative transmission line. And this paper confirmed that the amount of damping loads is not proportional to length of transmission line. The result of this paper will be used as important experiment data to predict the occurrence possibility of harmonic resonance previously.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.1377-1382
• /
• 2015

Power system restoration following a massive blackout starts with re-energizing Primary Restorative Transmission (PRT) systems at first. As power systems have been gradually enlarged and become more complex, periodical evaluation and reassignment of PRTs are needed. So far it has been decided by try and error approach by corresponding human experts to analyze and evaluate them. This paper presents an intelligent system that finds optimal primary restoration paths using analytic and heuristic knowledge from PSS/E data, and suggests an optimal PRTs depending on the condition of Ferranti effect or a reactive power capability margin of black-start generator. This system was tested in Korea Electric Power system, and showed a promising result.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.55 no.5
• /
• pp.191-194
• /
• 2006

Power system restoration following a wide area or complete blackout starts with energizing primary restorative transmission systems. During this primary restoration process, unexpected over-voltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. This is known as the harmonic resonance phenomenon that may cause burning out of transformer or other devices. Since the harmonic resonance originates from the nonlinear characteristics, it is very difficult to predict the occurrence of this phenomenon. This paper reports the analyses of the harmonic resonance occurred in domestic power system. Various analyses and results of the harmonic over-voltage is presented based on the PSCAD/EMTDC simulations.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.220-222
• /
• 2005

Power system restoration following a wide area or complete blackout starts with energizing primary restorative transmission systems. During this primary restoration process, unexpected over-voltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. This is known as the harmonic resonance phenomenon that may cause burning out of transformer or other devices. Since the harmonic resonance originates from the nonlinear characteristics, it is very difficult to predict the occurrence of this phenomenon. This paper reports the possible existence of the harmonic resonance in Korean power system. Analysis of the harmonic over-voltage is presented based on the various simulations using PSCAD/EMTDC.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.4
• /
• pp.172-176
• /
• 2005

Power system restoration following a massive or complete blackout starts with energizing of primary restorative transmission lines. During this primary restoration, inexpected overvoltage may happen due to nonlinear interaction between the unloaded transformer and the transmission system. This is known as the harmonic resonance phenomenon that may cause burning out of transformer or other devices. By now the harmonic resonance is reported in the extra high voltage system. This paper reports the detection of the resonance in Korean power system. Basic analysis and simulation of the harmonic overvoltage is presented using EMTDC.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.3
• /
• pp.117-121
• /
• 2005

Power system restoration following a massive blackout starts with re-energizing primary transmission lines at first. Some factors such as Ferranti effect, and line charging reactive power should be considered in this stage. Severe overvoltage may be induced by the Ferranti effect at the lines since it would be usually no load condition. And lack of capacitive reactive power will cause the self-excitation. This paper presents a new precise algorithm to analyze the primary restorative transmission system focused on the two major static overvoltage problems during the early restoration process.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.48-50
• /
• 2004

The energization of high voltage transmission lines and transformers, that is an inevitable process in most countries as the first restorative action for wide-area blackout, may induce overvoltages such as sustained overvoltage, transient overvoltage and harmonic resonant overvoltage. And these may cause damages to power system equipments or failure of surge arresters. The harmonic resonant overvoltage originates in switching operations and nonlinear characteristics of equipments. Actually it is difficult to predict the occurrence of harmonic overvoltage, since they result from nonlinear characteristics of transformers and other equipments. This paper describes the analysis of domestic primary restorative transmission system using PSCAD/EMTDC. The harmonic resonance is verified and the solution to prevent harmonic resonance is proposed in this paper. As a result, the PSCAD/EMTBC simulation showed slightly conflictive results that had been presented by IEEE Power System Restoration Working Group report.

• Proceedings of the KIEE Conference
• /
• 2002.11b
• /
• pp.161-163
• /
• 2002

Service restoration following a complete or partial collapse starts with reenergizing a transmission line from black-start generators. Voltage problems can arise from Ferranti effect as unloaded transmission line is reenergized. This Paper presents system analyser to develop for verifying the primary restorative transmission system. The algorithm which has been used in the analyser is to handle load pick-up compensating Ferranti effect. and terminal voltage and reactive capability limitation of black-start generators about self-excitation.