Buyung Sofiarto Munir

Covered Conductor Burn-Down Phenomena in Indonesia without Protection Relay Operation

All Aluminium Alloy Conductor-Shielded (AAAC-S) which is covered conductor is widely used as the temporary solution to mitigate the earth fault problem during application of bare conductor in Indonesia distribution system. However, the burn-down phenomenon of AAAC-S is often found in some cases and the protection schemes that have been installed on the distribution line is unable to detect any fault during the phenomenon. Due to no tripping order from protection relay, this phenomenon will lead some part of the conductor remain hanging in the air and still in energized condition. This condition may cause a potential hazard to the surrounding environment. Therefore, this study was performed to determine the cause of AAAC-S burn-down and the reason of protection equipment cannot work properly. Field investigation, modelling and simulation, and laboratory testing has been performed in this study to represent the condition in the field. The results show that the burn-down phenomenon of AAAC-S occurred due to many sequences of events. It started with insulation material breakdown that create pinhole, then during overvoltage phenomenon there will be earth fault condition through the pinhole. Finally, if the short circuit energy at a certain mechanical tensile exceeds the critical energy of AAAC-S, then the burn-down phenomenon occurred. In this condition, the protection relay is unable to detect the fault due to the working time of protection relay is greater than the critical burn-down time of AAAC-S, where it is being influenced by the location of earth fault, cross-sectional area of AAAC-S, and grounding resistance of the pole.

Effect of traction substation for high speed railway in Indonesia

This paper discuss about effect of traction substation for high speed railway in Indonesia. The purpose of this paper is to obtain magnitude of voltage and current unbalance due to traction substation that perceived by system and generator adjacent to traction substation. Analysis is performed by doing simulation of 5 scenarios in simple system model that created in power system simulation program. These 5 scenarios are being performed to represent the actual condition of Indonesia power system. Based on the analysis of simulation result, it can be stated that the magnitude of voltage and current unbalance on system and generator are influenced by magnitude of system short circuit level (SCL), position of supply substation to traction location, amount number of power plant near to traction location, percentage impedance of generator transformer, and the magnitude of generator load.

Recovery voltage study of capacitor bank switching for 150kV electrical system in Indonesia

In Indonesia, there are many capacitor bank installed to regulate the nominal voltage. Currently, the Recovery Voltage (RV) data related to the capacitor bank switching is unavailable, whereas this data is very important to analyze Circuit Breaker (CB) performance to understand whether it will success to interrupt the current or not. In addition, if the CB cannot retain the RV, it will degrade the CB contacts and possible to broke the CB. Therefore, this paper presents the study of RV for 150kV electrical system in Indonesia. The Result showed that the RV is affected by the source impedance value. Furthermore, for normal condition, the value of RV on the CB for capacitor bank with neutral grounded or ungrounded remains within the limits permitted by the standard. However, in the short-circuit condition, the Transient Recovery Voltage (TRV) and Rate of Rise of Recovery Voltage (RRRV) values can exceed the standard values. This TRV problem can be solved by grounding the capacitor bank. Meanwhile, RRRV problems can be handled by installed a surge capacitor that mounted and arranged in parallel (phase to neutral) to the CB.

Lightning data mapping of West Java province

Historical lightning data could be use to evaluate certain transmission line in power system network. By using historical data from lightning detection system with combined Magnetic Direction Finder and Time of Arrival method, lightning data mapping for West Java province was presented in this paper. According to the lightning data mapping from total recorded event, the peak current of the lightning was mostly ranged within 10 kA to 15 kA with median peak current value up to 20 kA. Bogor and Bandung had relatively high lightning density among other area within West Java province. Evaluation of lightning exposure for 150 kV transmission line on Bogor and Bandung were presented to determine which segment of the transmission line should be set as priority during routine monitoring and maintenance. Transmission fault or reclose event analysis using recorded lightning data was presented as a recommendation for further maintenance on the tower part prior to fault or reclose event, e.g., insulation string, ground wire or tower grounding.

Investigation of 150 kV capacitor voltage transformer breakdown during capacitor bank switching

This paper discuss about the investigation of 150kV capacitor voltage transformer (CVT) breakdown which is occurred simultaneously after capacitor bank disconnecting process. Analysis is performed referring to the last routine maintenance and digital fault recorder (DFR) data. Based on the analysis of both data and transient simulation analysis from the model created to represent the condition during the breakdown, it can be stated that the breakdown of 150kV CVT is due to aging of dielectric material in the CVT. Dielectric material aging of this CVT lead to the reduction of insulation overvoltage withstand in which eventually the CVT is breakdown after being hit by overvoltage stress during capacitor bank switching.

Phase arrangement for 500kV quadruple circuit transmission line in Indonesia

This study is performed to determine the phase arrangement for 500kV quadruple circuit transmission line that will be used in Indonesia. The phase arrangement selection is based on the value of electric field and magnetic field exposure. The purpose of this method is to obtain phase arrangement with minimum value of exposure to electromagnetic fields. Simulation is conducted using numerical analysis program which can perform finite element calculation. Based on simulation results, there are 6 phase arrangements from 1296 different phase arrangements that have minimum value of electromagnetic field exposure. The study is expected to be used as consideration in selecting phase arrangement for 500kV quadruple circuit transmission line in Indonesia.

Evaluation of transmission line parameter for non horizontal earth contour

Calculation of transmission line parameter such as capacitance and inductance had been done by several researchers. However, its common that in calculation, the earth surface under the transmission line is assumed to be horizontal. In fact, the earth surface is not horizontal but has an uneven contour. This paper explained a method to determine the parameter value of transmission line which passing through non horizontal earth contour, by entering the conductor height as a function of x axis for every segment of calculation. The total transmission line parameter values are the total sum of transmission line values of each segment. Calculation and simulation results show that the value of parameter is influenced by earth contour. The precision of the parameter value depend on the width of the segment that being used. However, the maximum voltage in switching transient has smaller relative error than the relative error obtained for transmission line parameter.

Studying of lightning surge transient effect on 500 kV quadruple circuit transmission line

This study determines the influence of lightning stroke current on 500 kV quadruple circuit transmission lines that will be used in Indonesias power system. Analysis is conducted in ATPDraw and multistory model is used in modeling of transmission tower. Lightning induced voltage across insulator strings is the main factor being considered in this paper. Therefore, effect of varying lightning current stroke front time, magnitude of lightning stroke current, and tower grounding resistance to insulator voltage is being analyzed. This study is expected can be used as consideration in determining insulation coordination and designing protective device on 500 kV quadruple circuit transmission line.

Switching transient and electrical resonance evaluation of 500kV four circuits transmission line

Four circuits transmission line is an alternative solution to transfer high quantity of electrical power. The transmission line has four parallel circuits on a tower and can be categorized as a new type of transmission line in Indonesia. Therefore, its electrical characteristics should be investigated. This paper studied the switching transient of the transmission line and evaluates the electrical resonance if the transmission line connects two substations with a line reactor in one side. Based on modeling and simulation results, during the switching process, the maximum transient voltage is less than the BSL (Basic Switching Impulse Insulation Level) value. On the other hand, for evaluation of electrical resonance phenomena, the proposed method is able to calculate the distance of transmission line which the resonance phenomena will occur.