Djoko Darwanto

EMC-based skin-effect grounding for reliable lightning protection system of antenna system

From EMC point of view lightning can be considered as the most destructive interference source for any sensitive electronic equipment. Its high impulse current conducted upon antennas cable armor could generate magnetic field, which induces dangerous overvoltage or current within equipment circuits. Such magnetic induction gives some adverse effects to the equipment, such as improper function or even destruction, leading to systems shutdown. This adverse phenomenon occurs frequently as lightning strikes the antennas communication although the tower is already protected with standard lightning protection system. This paper proposed a novel grounding method, so-called skin effect grounding, for reducing high impulse current of lightning possibly coming into radio room through antennas coaxial cable. The proposed method is working based upon skin effect principle, in which high frequency characteristic of impulse high current of lightning is considerably taken into account for more effective galvanic interference decoupling. The proposed method allows the reduction of impulse high current of lightning coming into radio room to the acceptable level below system immunity so that magnetic field generated can be considered as not harmful for the system. For years the proposed method has been implemented and well proved within the lightning protection system of communication center of oil & gas industries as well as telecommunication companies.

Macro Demand Spatial Approach (MDSA) with principal component analysis (PCA) on spatial demand forecasting for industrial area in transmission planning

Macro Demand Spatial Approach (MDSA) is an approach introduced in long time electricity demand forecasting considering location. It will be used at transmission planning and policy decision on electricity infrastructure development in a region. In the model, MDSA combined with principal component analysis (PCA) method to determine the variables that affecting electricity demand in industrial area. The variables are different for each load sector. Hypothesis on unique variables affecting electricity demand on every load sector in the industrial area were analyzed with qualitative methods and references. The variables have no significant effect can be reduced by using PCA. The generated models tested to assess whether it still at the range of confidence level of electricity demand forecasting. At the case study, generated model for South Sumatra Subsystem as a part of Sumatra System is still in the range of confidence level.

Macro Demand Spatial Approach (MDSA) combined with principal component analysis and qualitative analysis on spatial demand forecasting for main development area in transmission planning

Macro Demand Spatial Approach (MDSA) is an approach introduced in long time electricity demand forecasting considering location. It will be used at transmission planning and policy decision on electricity infrastructure development in a region. In the model, MDSA combined with principal component analysis (PCA) and qualitative analysis (QA) to determine main development area in region and the variables that affecting electricity demand in there. Main development area is an area with industrial domination as a driver of economic growth. The electricity demand driver variables are different for type of electricity consumer. However, they will be equal for main development areas. The variables have no significant effect can be reduced by using PCA. The generated models tested to assess whether it still at the range of confidence level of electricity demand forecasting. At the case study, generated model for main development areas at South Sumatra Subsystem as a part of Sumatra System is still in the range of confidence level. Thus, MDSA can be proposed as alternative approach in transmission planning that considering location.

Partial discharge analysis for predictive maintenance of generator of geothermal power plant

Generator is one of the most important apparatuses highly responsible for production process. Predictive maintenance is necessary for its high availability and reliability. It is reported that about 37% of problems of disruptive generator is caused by stator winding and about 40% of those problems is caused by disruptive insulation, to which partial discharge (PD) contributes. This paper presents partial discharge (PD) analysis for predictivie maintenance of generator of geothermal power plant. PD measurement was on-line conducted in a geothermal power plant using TGA-B IRIS Power with capacitor-coupled method and quarter system. The measurement data was used to determine PD type and its location for diagnostic purpose. Further, the analysis result and condition assessment became the basis of predictive maintenance.

State-of-the-art EMC regulation and conformity of products in Indonesia

Electromagnetic compatibility (EMC) can be considered as the ability of the electromagnetic apparatus to function satisfactorily without interfering the others or being interfered by the others. Nowadays, the conformity of electromagnetic products to corresponding EMC standards becomes of importance in order to cope with the mandatory requirements prescribed by the global market. The EMC conformity becomes the main part of quality assurance and safety of products.

Effect of grid cell size on ground flash density of distribution powerlines

This paper investigates the effect of grid cell size on ground flash density (GFD) of distribution powerlines. The study was based on the lightning data provided by local lightning detection systems and the analysis was conducted by overlaying ground flash map to the map of utility distribution network. The study result shows that GFD based on grid cell size with less magnitude has higher correlation with the outage events level of distribution powerlines.

EMC based reliability enhancement of emergency shutdown in a natural gas liquefaction plant

PT. Badak NGL is a company that operates the largest LNG Plant in Indonesia with maximum LNG (Liquefied Natural Gas) production capacity 22.5 MTPA and LPG (Liquefied Petroleum Gas) production capacity 1.0 MTPA from eight (8) trains. Lightning is still considered as a potential threat for gas companies operating in tropical region well known with its high isokeraunic level, Its adverse effects could be harmful for the sustainability of production and leading to economical lost and hazardous situation. During heavy rainy season with relative higher lightning activity, the gas company of interest experienced spurious trips after lightning strikes occurred. This paper presents EMC-based approaches for enhancing the reliability of emergency shutdown in a natural gas liquefaction plant. The approaches provide comprehensively EMC measures from reducing the interference source until enhancing the immunity of the instrument apparatus so that EMI problems disturbing PLC ESD/EDP systems during lighting strike could be solved.

Statistical analysis of partial discharge characteristics for predictive maintenance of generator of geothermal power plant

In order to guarantee reliable industrial power supply, predictive maintenance for generator becomes highly necessary. This measure is expected to reduce disruptive generator due to degraded insulation of its stator winding. Partial discharge (PD) is responsible for this disadvantage condition. The objective of this paper is present partial discharge (PD) analysis using statistical methods for predictive maintenance of generator in geothermal power plant. TGA-B IRIS was used for online PD measurement. The measurement data is analysed statistically to forecast the time of critical condition of stator winding of generator using vector autoregressive (VAR) method. The analysis result became the basis of predictive maintenance.

State-of-the-art of lightning protection system of high-rise building in Jakarta

Situated along equatorial-line region Indonesia is exposed to lightning with relative high isokeraunic level. Hence, high reliable lightning system becomes compulsory for high-rise buildings, which are subject to lightning strike with relative high probability. However, in fact, this is not the case when we realize the quality of lightning protection system installed within most of high-rise building at a glance observation. This paper presents state-of-the-art of the existing lightning protection system installed within high-rise buildings in Jakarta considered as the representative case of Indonesia. Some technical aspects of the surveyed systems are discussed from EMC point of view. Furthermore, an example design of EMC-based lightning protection system is described. Our survey results realize that high-rise buildings are mostly not well equipped with the proper lightning protection system. Furthermore, about 80% of high-rise buildings installed lightning protection system based on non-conventional concept, which is scientifically and legally not recognized. This adverse condition exists due to lack of knowledge of the society and weak law enforcement of the authorities.