Search

The less fossil fuel reserves in the world, especially Indonesia and environmental problems in the global sector caused by oil and gas exploration and mining, then alternative energy sources to replace fossil fuels or better known as renewable energy need to be developed. The Renun Hydroelectric Power Plant (PLTA) in North Sumatra has a water reservoir or so-called Regulating Pond with an area of ​​11.42 ha, the size of the Regulating Pond which is quite large is very appropriate if it is used for a Solar Power Plant (PLTS) because there is no land acquisition , and the Regulating Pond is more stable, there are no rising and falling contours. The solar panels used in floating solar panels on the regulating pound are 20,441 Polycristaline solar panels, 300 Wp power type Blue Sun Solar Energi BSM270-300P-60 (300W), the power generated is 6,123,300 Wp (6,123.3 kWp) or 6, 12 MWp. The batteries in PLTS consist of 275 series and 3.5 parallel and the total battery required is 1,100 JYC Batteries, OPzV3000 type batteries, and 9 inverters of the ABB brand PVI 500 TL CN with a power of 560 kW and a voltage of 360 V. The potential obtained from the PLTS planning in Regulating Pound for North Renun Hydroelectric Power Plant using Helioscope software simulation is 489,659 kWh/month.

Sambaran petir merupakan gangguan yang sering terjadi pada saluran transmisi dapat mengakibatkan tegangan lebih transient pada saluran transmisi merambat ke ujung jaringan dan akhirnya mencapai gardu induk. Pada gardu banyak terdapat peralatan sensitif terhadap tegangan lebih diantanya transformator. Untuk mencegah kerusakan akibat tegangan lebih dipasang Arester. Simulasi penelitian dilakukan dengan menggunakan menggunakan software Alternative Transient Program (ATP). Arester dimodelkan sebagai model IEEE. Sambaran petir disimulasi ke kawat tanah menara transmisi. Arrester dipasang dilokasi sebelum dan sesudah menara terakhir dekat dengan transformator daya. Arus surja petir standard IEC bervariasi dari 20 kA hingga 100 kA dengan kelipatan 20 kA. Hasil diperoleh tegangan lebih maksimum terjadi ketika sistem diijeksikan arus petir 100 kA dengan kondisi sistem belum terpasang Arrester dengan tegangan puncak yang terjadi pada masing-masing fasa berturut-turut, Fasa A, Fasa B dan Fasa C sebesar 3.649 kV, 2.836 KV, dan 3.473 kV. Tegangan minimum yang terjadi ketika arus petir 20 kA diinjeksikan kedalam sistem yang sudah terpasang Arrester, dan Arrester dipasang setelah menara. Nilai tegangan puncak yang timbul pada Fasa A, Fasa B dan Fasa C berturut–turut sebesar 191 kV, 175 kV dan 175 kV. Pemasangan Arester dapat menurunkan tegangan lebih pada setiap fasanya dan lokasi pemasangan arrester yang paling efektif adalah dekat dengan transformator daya. Kata kunci

Pembangunan Gardu Hubung Teladan bertujuan untuk percepatan dalam pemindahan dan pengendali beban listrik ketika pemadaman listrik terjadi, program pelaksanaan pemeliharaan atau untuk maksud mempertahankan kontinuitas pelayanan di kota Medan. Rekonfigurasi jaringan dilakukan dengan memindahkan beban sebahagian dari Penyulang TT05, Penyulang DA05, Penyulang DA06 dan Penyulang DN03. Beban penyulang tersebut dialihkan ke Gardu Hubung Teladan melalui Penyulang ACSTL01 sebesar 54,4 amper, Penyulang ACSTL02 sebesar 28,1 amper, Penyulang ACSTL03 sebesar 34,4 amper dan Penyulang ACSTL04 sebesar 31,5 amper. Rekonfigurasi jaringan di Gardu Hubung Teladan mengakibatkan perubahan data parameter dari jaringan saat ini diantaranya drop tegangan yang diijinkan maksimum 5 %, tegangan kerja pada Gardu Hubung Teladan masih terpenuhi. Dengan pembangunan Gardu Hubung Teladan diperoleh konfigurasi jaringan yang optimal sesuai standard teknis Persentase Vd (Voltage Drop) terbesar berada di section 3 Penyulang DN03 Gardu Induk Denai sebesar 2,73%, sesuai SPLN no 72 tahun 1987 masih terpenuhi.

The increase in the telecommunications network was accompanied by the addition of the number of BTS (Base Transceiver Station) in various regions. The BTS (Base Transceiver Station) tower is built with a minimum height of 25-100 meters. BTS towers are equipped with external and internal grounding protection systems that are designed and installed in accordance with SNI. The protection system is a unified protection system for towers and telecommunications equipment from lightning strikes. Lightning strikes occur randomly which cannot be ascertained and their occurrence is controlled and lightning strikes also cause damage to the object that is struck. ATP Draw is a graphical program from the Electromagnetic Transient Program (EMTP) for Windows. Software Alternating Transient Program (ATP Draw) is used for digital simulation of impulse waves. In this software a lightning protection system is modeled in the form of an electrical circuit, and a lightning impulse waveform against a lightning protection system circuit. analyzed the lightning protection system on the BTS tower by performing simulations using ATP Draw software with a power line model with Standard IEC 1.2 x 50 s showing the simulation results of a lightning surge current of 30389 A. for a lightning surge input current of 80 kA, 36088 A for a lightning current input lightning surge of 95 kA, and 37987 A for lightning surge input current of 100 kA. For modeling the standard CIGRE 3.3x77.5μs power line, the simulation results for a lightning surge current of 40644 A for a lightning surge input current of 80 kA, 48264 A for a lightning surge input current of 95 kA, and 50805 A for a lightning surge input current of 100 kA.

— Sistem proteksi berfungsi untuk melindungi peralatan dari kerusakan pada saat terjadinya gangguan serta melokalisir gangguan agar tidak meluas. Dengan sistem proteksi yang baik, maka kerugian yang tidak diinginkan bisa dihindarkan, terutama pada peralatan vital seperti pada generator dan transformator Salah satu peralatan yang berperan dalam sistem proteksi adalah rele proteksi overall diferensial yang digunakan untuk melindungi generator dan transformator.Rele ini melindungi generator dan transformator dari gangguan-gangguan internal seperti hubung singkat antar fasa, hubung singkat dari fasa ke tanah, maupun hubung singkat antar belitan.Rele ini bekerja berdasarkan setting arus dan waktu operasi yang sudah ditentukan sehingga bisa bekerja dengan cepat dan tepat sasaran.Rele bekerja dengan membandingkan arus yang masuk dan keluar. Rele akan mendeteksi adanya gangguan dan memerintahkan pemutus tenaga (PMT) untuk membuka (trip). Sistem proteksi yang baik ditunjang oleh setting yang tepat pada rele diferensial guna mencegah terjadinya kegagalan proteksi dan meningkatkan kehandalan dari system.Penelitian ini bertujuan menganalisa kinerja rele overall diferensial dan mensetting rele overall diferensial pada generator dan transformator.Metode yang digunakan untuk menentukan setting rele diferensial yaitu dengan mencari data sekunder di PT PLN (PERSERO) dan mencari referensi jurnal yang sesuai dengan penelitian yang dilakukan. Kata kunci : Sistem Proteksi, Rele Diferensial, Rele Overall Diferensial dan Setting Rele Abstract — Protection system functions to protect equipment from damage when interference occurs and to localize the interference so it does not spread. With a good protection system, then unwanted losses can be avoided, especially on vital equipment such as generators and transformers One of the equipment that plays a role in the protection system is differential overalls protection relays that are used to protect generators and transformers. These cables protect generators and transformers from internal disturbances such as short circuit between phases, short circuit from phase to ground, or short circuit between turns. This relay works based on the current setting and operating time specified so that it can work quickly and precisely on target. incoming and outgoing. Rele will detect interference and instruct the power breaker (PMT) to open (trip). A good protection system is supported by the right settings on the differential relay to prevent protection failure and increase the reliability of the system. This research aims to analyze the performance of the differential overalls and the setting of the differential overalls on the generator and transformer. The method used to determine the differential relay settings is by looking for secondary data at PT PLN (PERSERO) and looking for journal references that are consistent with the research conducted. Keywords : Protection System, Differential Relays, Differential Overall Relays and Rele Settings

Water serves to transport minerals, vitamins, proteins and other nutrients throughout the body. Body temperature balance will greatly depend on water, because water is a lubricant of the body's tissues as well as pads of joints, bones, and muscles. Once the importance of water for human survival so that the availability and sustainability of water for living things must be maintained. In the life of modern society in Indonesia today, the supply of clean water to a community is usually supplied by local government-owned water companies. But due to network limitations or production capacity, often not all communities can enjoy the clean water facilities. Islamic boarding schools are religious-based educational facilities whose management is still constrained by funding problems. So the facilities are always in a limited state. As is the case with the Quran Al-Fitrah tahfidz Islamic boarding school, which is located in Namo Rambe, which has difficulty in providing clean water to be drunk at the boarding school.

Saluran transmisi harus dirancang dengan mempertimbangkan beberapa aspek seperti kehandalan, ekonomis, dan keamanan. Oleh karena itu, maka sistem proteksi saluran transmisi harus bekerja dengan sensitif, selektif, cepat, maupun handal pada saat terjadinya gangguan sambaran petir. Rele jarak dapat mendeteksi titik gangguan pada saat saluran transmisi mengalami gangguan akibat sambaran petir. Penelitian ini bertujuan menganalisa kinerja Rele Jarak dalam menentukan titik gangguan akibat sambaran petir pada Gardu Induk Glugur – Payageli. Dalam penelitian ini akan menganalisa berbagai data pendukung yang didapatkan dari PT PLN (PERSERO) untuk mengetahui setting an Rele Jarak dalam menentukan titik gangguan. Setting pada Rele Jarak yang tidak tepat akan mengakibatkan rele jarak gagal bekerja sesuai dengan zona nya. Dalam penelitian ini rele jarak bekerja sesuai dengan standard SPLN No. 0520-2K./DIR Tahun 2014 tetapi Rele jarak dalam menentukan titik gangguan berdasarkan jarak aktual dilapangan memiliki kesalahan pembacaan diatas 3%.

This study aims to get the best performance of cellular communication based on variations in empirical radio propagation models and the number of base stations (BTS) in urban areas. The model is designed and simulated by using programming software. The observed performance parameters are the quality of the radio link and drop call. Simulation results found that the increase in base stations and mobile stations (MS) antennas height resulted quality increment of the radio link and decrement of drop call rate for all empirical models. Likewise, an increase in the number of BTSs to four in system, exerted quality improvement of radio links and decrement on drop call rate. It was also found that each increase in antenna height for the Hata radio link model produces zero dropped call as the quality of the Hata radio link is above the threshold, even when the antenna height is at the lowest.

This paper discusses the arrangement of differential relays at the Langsa substation. The ratio of CT mounted on the transformer to the primary side is 150/1 A and on the secondary side is 1000/1 A. This result is taken with consideration of the current value calculated from 127.02 A on the primary and 952.62 A on the secondary side. For the sensitivity of the mismatch error is still good because it is still under 5% on the primary side which is 0.89% and the secondary side is 1.13%. The differential current also shows the normal condition of 0.1 A and the restraint current 1.205 A. Using the ETAP 12.6.0 simulation, relay can work well when interference occurs at the current setting indication 1.29 A is greater than the operating current 1.65 A and the relay does not work during an external fault with a setting current of 1.29 A equals to an operating current of 1.29 A.

The design of the substation grounding system is very important to provide safety and protection for both the equipment and operators around it. To achieve this condition, the design must meet predetermined standards. Commonly the grounding is grid construction. On the other hand, an efficient system design is also needed. One of the determining factors is the total length conductor used. An attempt to minimize the number of lengths was carried out to improve efficiency, namely, modify grid conductor and ground rod parameters but still meet the safety criteria determined according to the IEEE-80 2000 standard. The grid grounding system generally uses copper conductors. This paper discusses the efficiency that can be expected by replacing copper conductors with other cheaper materials, namely aluminum 5005. The ground area used is rather small. The design and analysis are carried out with the SGD (Substation Grounding Grid Designer) application developed on Lab-VIEW software with a case study of 2×500 MVA Galang substations. The parameters of the grounding system considered are touch voltage, step voltage, potential grid diameter of the earth conductor, and earth ground resistance. From the observation, it was found that the modification of the substation grid grounding system can improve the average efficiency of 75.4%.

This research is an effort to obtain optimal parameters for mobile communication handover by observing variation in antenna height of the Hata propagation channel model. Mobile network is modeled by either a network consisting 2 base transceiver stations (BTSs) and 3 BTSs. The observed parameters are active set size and handover rate. Research work is carried out by using simulations. Simulation results show correlations between performance parameters and BTS antenna height. By utilizing the locally optimal algorithm, performance parameters can be further optimized. The optimization reduces the average size of the active set and handover average rate as well as maintains the signal quality.

All Grounding planning of a substation is important and various design applications are available using calculation uniform soil resistivity, even though actual resistivity data measured is more than one layer. This is caused by limited availability of the application in processing data only for resistivity one layer. Substation grounding grid application (ASPG) 1.0 can be used for designing grid grounding. The ASPG was developed from Lab View software and has ability to data process for resistivity two-layer that to refer IEEE Std. 80-2013. Grid grounding resistance is considering a combination of grid conductor and ground conductor. This paper discusses the calculation of the magnitude of substation grid grounding using formulas developed by Schwarz, Sulivan and Sunde. The design result obtained is more accurate in substitute resistivity for resistivity two-layer model and calculation grounding resistance substation.

The grounding resistance value is directly proportional to soil resistivity. The resistance value is better as low as possible for the equipment body grounding. The purpose is to provide a path of the short circuit current flows to the ground as protection and safety personal and also the equipment. The soil resistivity great is influenced by moisture and substance content in the soil. The highland soil and rocky soil commonly are poor the soil resistivity. Transmission line towers can be not avoided through the highland region. To reduce the soil resistivity value can widely be carried out by addition low material resistance (LMR) or LMR composite other materials. This research, to mitigate the value of the soil resistivity can be carried out by addition low material resistance (LMR) Zeolite composite with NaCl, Charcoal, and Soil. Various compositions of the LMR, NaCl, and Charcoal were used to find the lowest grounding resistance at certain depth. The three-point method was used to measure the grounding resistance value. The research result gives information that best composition is 90% Zeolite, 5% NaCL and 5% charcoal for the rod depth of 1.2m, the resistance decrease from 94.3Ω down to 5.3Ω (94.4%). The LMR Zeolite is dominant influence to reduce the grounding resistance.

Voltage sag is one of the power quality disturbances most frequently by customers because it can cause economic loss for the customers especially industries and commercial customers. The main source of voltage sags are faults in transmission and distribution beside two others namely motor large starting and transformer energizing, both the voltage sags have less effect on the equipment. Voltage sags can cause degradation performance of the equipment, and it depends on the magnitude and the duration. The voltage sags that occur in the power system can be compensated with installed Static VAR compensator (SVC) and Static synchronous compensator (STATCOM) in the distribution system bus. The purpose of the study is to compare both types of the device used to mitigate voltage sags in simulation using Alternative transient program (ATP) software. The voltage sag results from the short circuit faults. The method proposes the installation of the two compensator devices alternatively at one of the IEEE thirteen busses systems. The result shows the STATCOM is better than the SVC to handle mitigation of voltage sags compared with the SVC.

The primary source of voltage sags is a short circuit fault in the power system. Three-phase fault can result in a more severe effect on the equipment. The voltage sags have affected significantly on performance degradation of the induction motor. The motor behaviors can be investigated in terms of rotation speed, torque, peak current, and recovery time during and after voltage sags. This study is to investigate induction motor behavior under voltage sags using the alternative transient program (ATP) draw software in simulation models. Distinct rated capacity, mechanical inertia, and loads torque (constant, linear, and variable) of the motor were used to investigate the motor’s behavior during and after sag end. Voltage sags resulted from three-phase fault at the certain locations in industrial power systems. The motor rotation speed decreases in slightly distinct during voltage sag but recovery times required to motors are longer for the large capacity motors. The large motors create the larger inrush current can reach more than five times its nominal. The motors with constant load toque subjected to voltage sag lead loss control in speed.

Insulators are many used in air transmission and distribution systems and also substation. Because it's in the air, and its performance is influenced by age and the level of pollutants attached to it. Types of pollutant content attached to the insulator have effect on leakage current and flashover voltage on the insulator performance. Insulators polluted result in reduced surface resistance of insulator. This paper investigated influence of artificial pollutants in various types on porcelain and glass of disc insulators in dry and wet conditions which are the pollutants are KNO3, ZnSo 4 , S (Sulfur), CaCO 3 and KCl. The insulators were tested in different pollution level designated as equivalent salt deposit density (ESDD). Based on insulators test result of various pollutant attached on insulator result in insulator performance are different. Pollutant types of KCl, KNO 3 and ZnSO 4 result in leakage currents flow on insulator surface are large. Insulators polluted by ZnSO 4 and KCl cause flashover voltage on insulators decrease significantly.

Substation design that refers to IEEE Standard 80–2000 can be carried out through manual calculation. Considering that there are lot of data involved used and also repeated calculations, it will be very difficult and requires high accuracy. Therefore, a computer-based computing system is needed to solve this problem. This paper discusses an application modelling of LabViewgraphical user interface to provide convenience in designing the substation grounding grid. Some options have been developed such as grounding grid resistance calculation method, conductor diameters determination, grounding grid selection with ground rod and without ground rod and weight body. The effect of any changes in design can be known directly and compared with limit of the touch voltage and the step voltage allowed. For validation, the model used data from Std. 80–2000 and compared with some design model already existed. As a result of this application, grounding grid design process will be easy, more accurate, and faster.

In web-based student information system development, usability requirements are the most important of non-functional requirements since they determine the acceptability of systems. Nevertheless, usability requirements are usually unconsidered in early stage of system development. Mostly the developers consider the functional requirement with expected to develop system with high function and technology. But high function without usability is not the main of the aims of system development. This paper aims to propose a requirement to assist and support the development process of student information system. This study conducts in-depth interview method to capture usability requirement which involves administrator, programmer, lecturer, and students. By using several task to guide user operate the system, some issues is discovered. Based on study, the result discovers that interactive design, task completion efficiency and interactivity is impact to usable system. It means the study need investigate which elements that influcence task completion efficiency and interactivity.

Long transmission line has many problems, one of which is the voltage drop at the load center. The Banda Aceh subsystem is a sub-system with a load center connected via a 150 kV transmission line with a North Sumatra subsystem. This transmission line has a length of nearly 700 km. Very low voltage in the subsystem Banda Aceh occurred in the operating system when only one generating unit on the plant Nagan Raya. The increase in voltage drop is done by installing a capacitor bank in the Banda Aceh subsystem. The results of installing capacitor banks can increase system voltage in the range of 7–8 kV, enlarge the power transfer from the North Sumatra subsystem and reduce the risk of black out due to low voltage on the system.

Lightning has always been a dangerous threat to power system equipment consisting of: power plants, substations, transmission lines and distribution lines. Commonly, the overhead high voltage transmission line is subjected to lightning strikes. Therefore the protection level against lightning is determined based on the level of insulation of equipment. To prevent damage due the equipment due to a lightning strike, an arrester is used. In this study, three models of arrester are used as comparison viz. IEEE arrester model, Micaela arrester model and Karbalaye arrester model. The system were simulated by using the Alternative Transients Program (ATP) software. The results show that the lightning arrester is declared successful in protecting the transmission system, where the three lightning arresters have Margin Protection (MP) arrester which reaches 28%. In the simulation, it is known that the IEEE and Karbalaye arrester successfully breakdown the lightning current in transmission system so that the transient overvoltage recorded on the transformer does not exceed the Basic Insulation Level (BIL) value of the transformer. While the Pincenti arrester has also succeeded in reducing the voltage on the system but its value is greater than the transformer BIL of the substation, Teluk Dalam, Nias

The increase in load which increases every year causes a decrease in voltage on the line which is getting bigger. The voltage drop on the transmission line greatly affects the quality of the voltage. The voltage that arrives at the electrical equipment will decrease which in turn reduces the performance of the equipment. The power flow study uses the Fast Decoupled method, the voltage on each bus can be determined. The performance parameters observed are the value of the power factor, voltage, active power, and reactive power to determine the parameters for the location and size of the capacitor bank capacities and the static var compensator (SVC). By increasing the power factor in the range of 0.85pu to 0.95pu, the bus voltage can fulfill the SPLN standard. Parameters are designed and simulated using the ETAP programming software version 12.6.0 by testing each bus that experiences a voltage drop in turn based on the voltage limit and the power factor value ≤ 0.85pu. Furthermore, several buses with the appropriate capacity rating are selected to increase the voltage on the system. The simulation results will show the effectiveness of the capacitor bank and static var compensator (SVC) to increase the voltage value on each bus.

Computation of the generator neutral grounding system through a distribution transformer can be done through manual calculations. A lot of data is used in calculations so that the possibility of recurring calculations. This is very difficult and causes a large difference in the calculation results. Therefore, a computer-based computing system is needed to overcome problems like this. Several papers have been developed on the calculation of the voltage capacity through medium grounding, the length of the electrodes attached to the ground of the generator, one-phase faults to the ground, and zero sequence current disturbances. Therefore, this paper discusses modeling using the LabView Graphical User Interface (GUI) application to create it easier to design neutral grounding for equipment. As an implementation, modeling using Std. C62.92.2TM-2017 data and the results of the generator neutral grounding design can be easy, faster, and more accurate.

This paper presents the influence of distributed generation (DG) location and capacity for mitigating voltage sag caused by faults. The voltages sags are caused by the faults were simulated on the IEEE 13 bus system for single line to ground close to 650 and three-line phase faults at bus 646 using Alternative Transient Program (ATP) software. The voltages are monitored at every buss system. The DG is installed for one DG, two DG and three DG as the alternative. The DG locations are installed based on trial and error. DG total capacity is 2/3 load total installed in the system. As the alternative DGs installed viz. for one DG at Bus 611 with the capacity of 2.5 MVA; Two DGs at Bus 611 and Bus 680 with their respective capacities of 1.25 MVA; Three DGs are located at Bus 611, Bus 680 and Bus 633 with their respective capacities of 1 MVA. The results show that DG location placement in many locations gives the better results for mitigating voltage sags.

The voltage drop in distribution line unavoidable but can be reduced until the allowable limit. The voltage drop occurred due to currents flow in impedance lines. Harmonics caused by non-linear loads that are often found in the industrial used electronics devices. This study is to discuss the application of static var compensator (SVC) to improve the power quality in distribution lines. Harmonics analysis of the loads industries are modelled as arc furnace and adjustable speed drive (ASD) using software ETAP simulation. The loads are connected to the IEEE 14 busses system. Fast decoupled method was used for investigating the voltage drop at each buss. Harmonics analysis was carried out to find harmonics level contents i.e., total harmonics distortion of voltage (THDV) and current (THDI). Values of THDV and THDI resulted are evaluated by state electrical company (PLN) standard. The load flow study result shows that there are some busses have voltage below the standard and harmonics analysis beyond the allowable limit but the voltage at Bus 14 is lowest, therefore SVC is connected to it. The results show all the voltage is fulfilling the standard. The SVC installation on this case is less significant it affects on mitigating harmonics.

AC contactor many found in industrial sectors. It function is to link induction motorto utility supply and recognicedsusceptible to voltage sags. The contactorconsist of primary and auxiliary contacts. The primary contact can opened if it is supplied by voltage sags. In an industry, a contactor is used to keep electric motors abruptly restart when the voltage sag return to normal. This studydiscussesbehaviour of three contactors caused byvoltage sags and interruption.The contactors are fabricated from distinct manufactures. Voltage sag characteristics used are sag magnitude, sag duration and also point on wave (POW) of sag initiation. The testing results show that the contactors performances are greatly influenced by them. The contactors are more susceptiblewhen theywere served with deeper and longer voltage sag. Susceptiblity of contactors to sag durationis rise when they were supplied by voltage sags with the POW near to 90o. The contactors susceptibities decrease when thesag occurs at three POWs which are0o, 45oand90o.

This paper aims to analyzing and probing the influences of power system harmonics on a differential relay used for distribution transformer protection. The increased use of nonlinear devices in industry, commercial and residential areas can lead to a significant increase the level of harmonic distortion in the power system. This harmonic has the significant effects to the differential protection systems components such as current transformer (CT) and relay. The CT tends to saturate due to the presence of current harmonics in power system, so it will produce magnitude secondary current error and make the differential relay to miss operations. The harmonic distortion effects on the differential protection have been investigated through laboratory test. To determine the CT errors when operates under harmonic condition, the CT has been test with certain level of THDi. The result of this testing was found that with increasing of the THDi, the magnitude of secondary current error increased and differential relay will operate at no fault conditions.

The investigation of the direct current (dc) bias effect on single phase power transformer through their harmonics performance is present in this paper. The experimental study is done by the dc bias current injected simultaneously with alternating current (ac) source to primary winding of transformer. The input ac voltage to primary winding is maintained constant during investigation and the dc currents increased gradually. Compare to pure ac power applied, the results show that the waveforms distorted when the dc bias exist. The pulsated waveforms are pushed to half cycle in which the bias current is in the same direction as magnetizing current (unsymmetrical pulsated) and even harmonics are significant.

This paper analyzes effects caused by voltage sag types A, B, C and D on induction motor based on experimental test. The effect can be investigated in term the current peaks and speed variation. The magnitudes depend on magnitude of sag and duration, voltage sag types, during and recovery voltage sag. Several of voltage sag characteristics have been conducted in different magnitude, duration and sag types. The results show that the current peaks generated reach more than 4 times of normal current and it was achieved at recovery voltage instant. Sag magnitude has great influence on the current peak but sag duration is not significantly. Type A voltage sag only can cause the motor stop running and it was achieved when it was subjected to sag magnitude of 10% and 6s in duration. The motor stops running in shorter duration when it was subjected to interruption with sag duration of 4s. Therefore voltage sag of type A lead to more severe on induction motor if compared with other sag type. This is according to number of phase that experience sag. The magnitude and duration of voltage sags have influenced significantly on the motor speed only for low sag magnitude and long sag duration.

This research focused on the effect of harmonic to the performance of current transformer (CT) operates under harmonic conditions. Due to the increasing of harmonic in power system, the CT did not perform well. The CT may saturates due to the presence of voltage and current harmonics. In this project, a laboratory test was conducted to investigate and analyze the influence of harmonics to the CT performance. This CT has been test with different Total Harmonic Distortion Current (THDi) at primary side and constant primary current. The experiment result shows the secondary current CT errors will increases when THDi increases.

Increasing demand for large-scale power delivery with high reliability and quality necessitates the use of multiple distributed energy resources to be connected in parallel; for example, parallel inverters operation. Proper operation of parallel inverters requires sophisticated control techniques and many have been proposed and continue to evolve. This paper depicts the droop control techniques for the parallel inverter systems. The recent improvements and variants of this control technique are presented

Variable speed drives (VSDs) are widely used in various applications mainly in process industry need constant rotational speed. It is developed from power electronic components thus saving energy in its operation. Unfortunately it is susceptible against power quality problem for example voltage sags. The VSD may be disruption or drop out when it is supplied by voltage sags and it is determined by sag characteristics. This study is to investigate effect of voltage sags Types I, II and III on VSD through laboratory testing. The voltage sags characteristics are generated from voltage sag generator (Shaffner 2100 EMC). The effects are presented in susceptibility curves in disruption and drop out conditions. The curves resulted are evaluated by standard curve recommended. Test results show that voltage sag Type I cause the VSD disruption only, whereas two types sag other result in the VSD disruption and also drop out. Evaluation results explain a few test points are in operation area for disruption condition whereas test points for dropping out far below the threshold recommended. Hence the VSD has good quality to voltage sags.

Voltage sags and interruption are one of most important of power quality problems. They can influence performance of equipment such as induction motors. They are generally caused by short circuit faults in transmission and distribution systems which propagate in entire of power systems. When their appear at a motor terminal, its effects are the speed and the torque will decrease to a level lower than values of the normal and even the motor become stall if magnitude of the voltage sags and duration exceed certain limit. The voltage can return to nominal voltage after end of the voltage sag and interruption. The motor will experience re-acceleration to normal condition is accompanied by large inrush current. A study on induction motors was carried out to confirm these effects. Single-phase and three-phase of small induction motors were used for investigating the effects caused by symmetrical voltage sags and interruption through experimental and simulation.

This paper presents a study to investigate response of adjustable speed drives due to voltage sags. A small ASD of 0.39 kW, 50/60 Hz, and 400-480 V was used for testing how drives will respond to voltage sag types; A, B, C and D. The drive response is influenced by sag magnitude, sag duration and phase angle shift. Behavior of the diodes rectifier for conducting is influenced by sag magnitude and phase angle shift represented by sag of types C and D. The diodes rectifiers are reverse biased when it was supplied by voltage sags. Even though there are no charging currents to dc bus capacitor during voltage sags, the drives did not directly trip to certain sag magnitude and sag duration. Sensitivity of the ASD to voltage sag types is presented in voltage tolerance curve. Sag of type A produces highest sensitivity on the ASD and it trips for sag magnitude of 62.5% and 250 milliseconds in duration.

This paper describes the modeling of distance relay using Matlab/Simulink package. SimPowerSystem toolbox was used for detailed modeling of distance relay, transmission line and fault simulation. Inside the modeling, single line to ground (SLG) fault was choose to be the fault type and Mho type distance characteristic was choose to be as the protection scheme. A graphical user interface (GUI) was created using GUI package inside Matlab for the developed model. With the interactive environment of graphical user interface, the difficulties in teaching of distance relay for undergraduate students can be eliminated.

Faults can occurred at the transmission line due to lightning strike, broken conductor, cross arm or tower falls, danger tree, crane or animal encroachment, polluted insulator etc. Each type of fault will represents a fault resistance value. Fault resistance will affects the accuracy of protection relays in fault location and fault zone detection. Phase to phase fault is one type of unsymmetrical fault at the transmission line. This paper represents the accurate way to calculate the actual phase to phase fault resistance value by using data from both local and remote substations. From the finding, the actual fault resistance can be represented by fault resistance as seen from local substation in parallel with the fault resistance as seen from remote substation. To prove the finding, simulation has been carried out and the results show the validity of the proposed theory.

This paper presents a simplified method for determination the separation of hysteresis and eddy current losses characteristic of power transformer. The model tuning is performed by energized the transformer core in no-load condition with sinusoidal voltage waveform, different frequencies and the magnetic flux density in transformer core always constant maintained. The core loss splitting is obtained by using two-frequency method. The results show that at low frequency, the appearance of hysteresis loss is visible, but at higher frequency, the eddy current loss is more significant.

This paper describes an adaptive distance relaying scheme which can eliminate the effect of fault resistance on distance relay zone reach. Distance relay is commonly used as main protection to protect transmission line from any type of fault. For a stand-alone distance relay, fault resistance can make Mho type distance relay to be under reached and thus the fault will be isolated at a longer time. In this scheme, the relay detects the fault location using a two-terminal algorithm. By knowing fault location, fault voltage at the fault point can be calculated by using equivalent sequence network connection as seen from local terminal. Then, fault resistance is calculated by using simple equation considering contribution from remote terminal current. Finally, the compensation of fault resistance is done onto calculated apparent resistance as seen at relaying point. The modeling and simulation was carried out using Matlab/Simulink software. Several cases were carried out and the results show the validity of the scheme.

Main source voltage sags are short circuit faults in power systems. These fault currents propagate entire the circuits connected with them. After the fault is removed by circuit breaker opened, the system voltage may recover to its normal value, the motor will re-accelerate during recovering process accompanied by high transient currents. This paper presents an experimental test to investigate effect of various characteristics of voltage sags such as magnitude, duration, repetitive and multistage of voltage sags on performance of induction motors. Several small induction motors were used to this purpose. Sag magnitude significantly influenced on the current peaks and speed variation whereas sag duration significantly influenced only on the speed. The motor responses to magnitude and sag duration in repetitive and multistage events are different.

Sensitivity of electromagnetic contactors for voltage sags and non-sinusoidal voltage supply has been carried out by laboratory testing. Effects of sag characteristics such as; sag magnitude, sag duration and point on wave of sag initiation to be considered on contactors behavior. Contactors are subjected to voltage sags of depth varying, sag duration varying 5 ms to 600 ms, different point on wave and under different non-sinusoidal conditions. A Schaffner Profline 2100 EMC has been used as sag generator to create sag characteristics. The results show that sensitivity curves of the contactors depend on sag magnitude, sag duration and point on wave, whereas influence of non-sinusoidal voltage is slightly different.

Uninterruptible power supply (UPS) sits between a power supply such as wall outlet and devices to prevent undesired feature that can occur within the power source such as outages, sags, surges and bad harmonics from the supply to avoid a negative impact on the devices. This paper presents a photovoltaic (PV) powered UPS using smart relay. It is a standby UPS whereas if the main power source fail to supply power to loads, a battery powered inverter turns on to continue supplying power. The battery is charged by the PV using solar charger and transfer switch controlled by smart relay. The UPS was tested to a load of 240 V, 20 W AC aquarium water pump. The test result shown that the UPS perform well, when the main power source fail, the battery could power inverter and the smart relay control the transfer switch, the load and battery current were 0.1 A and 1.56 A, respectively.

Voltage sag is an issue that is becoming increasingly important to electricity consumers at all level of usage. These result from with increasing use of electronic equipment in several sectors for the reason to improve energy efficiency and performance. Customer's included in low voltage environments mostly are sectors: Commercial, Residential and Light industrial. In these sectors many found equipments such as television, microwave ovens, personal computers, printer, lighting, heating ventilation air conditioners, motor contactor etc. Using with high efficiency fluorescent lighting with electronic ballast, single phase switch mode power supplies for computers, contactor for protecting motor from suddenly restarting when the voltage is recovered. These equipments are characterized as highly susceptible to voltage sags. Voltage sags are most frequent among various types of power quality disturbance faced by many consumers. Source of voltage sags are generally caused by short circuit faults associated with equipment failures on the supplying power system. Voltage sags normally do not cause equipment damage, but it can easily disrupt the operation sensitive equipment. Effects produced by voltage sags are various generally depending on its characteristics and equipment. The magnitude and duration of the sags are commonly used to evaluate sensitivity of equipment. The other characteristic such as point on wave of voltage sag initiation is significance influence to be considered. This paper presents voltage sag tolerance levels curves of three equipments sensitive to sags namely; personal computers, contactors and lightings. A Schaffner “Profline2100” has used to generate voltage sags and testing to get sensitivity of the equipment.

This paper discussed about influence of voltage source types on harmonic characteristics. Usually, the voltage source is sinusoidal. But in actually, the condition of the load is has voltage sources through the elements where the output voltage of element as input to load is did not pure sinusoidal, for example at PCC between transformer and linear load and nonlinear load. The research has done with Schhafner Power Quality Analyzer. To describe the harmonic characteristic due to types of voltage source will shown as IHD, p.f., THD, and harmonic energy losses cost from measurement. As voltage source in this research are sine wave and combinations of 3rd, 5th and 7th harmonic order, and square waveform are create by means of Schhafner Power Quality Analyzer.

Nowadays nonlinear loads are widely used in many consumer equipment and power systems. The main problem in using of nonlinear loads is harmonic distortion. This paper will discuss the effect of application of shunt capacitor banks and shunt filter banks to reduce harmonic distortion in the power system, which will result in the increasing of the system efficiency. With installed of shunt capacitor banks and shunt filter banks, the voltage and harmonic distortion at each bus will be improved. This research was used MiPOWER software. The results will be shown in total harmonic distortion (THD), telephone influence factor (TIF) and voltages at each bus in the system.