Generator Electrical

Teknik Elektro Segitiga Daya

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the photovoltaic and wind power Hybrid Project in Indonesia

The project called the "Oeledo Project" started in 1997, and was completed in 2000. Oeledo itself is a village located in Pantai Baru District, Rote-Ndao Regency on Rote Island, East Nusa Tenggara (NTT). From Kupang, the city of NTT Province, Rote can be reached in about four hours by ferry via the Pantai Besar pier. The distance from this port to Oeledo is about 22 kilometers, but it can be reached by a 1.5 hour road trip because the road is dirt and damaged. This project was officially submitted to the Oeledo community in 2001. The Oeledo project consists of socio-economic, financial and technical studies, management capabilities of rural electrification schemes using a hybrid system and participating in community development steps. The project was designed and implemented by the e-7 Network of Expertise, an international organization consisting of nine leading power companies from the G7 countries (Canada, France, Germany, Italy, Japan, UK and the United States), in collaboration with the Government Indonesia and local non-government organizations. The hybrid system supplies 127 customers with 220 Volt AC power. Wind energy and photovoltaic generate electricity which is stored in batteries and supplied to consumers for 24 hours. Wind energy consumption is measured and paid on a base month to the Village Electricity Manager (PLD), who provides and ensures proper electricity service to customers. Before the Oeledo project, ordinary people used kerosene, candles and batteries to meet their electricity needs at a cost of around Rp. 10,000 to Rp. 20,000 per month. Whereas by using renewable energy technology, with a rate of IDR 800.00 / kWh and a specified capacity cost of IDR 5,000.00 (10,000.00) per 0.5 (1) A per month (circuit breaker) promoted by PLD, it is acceptable. by the community and set forth in the service agreement between the customer and the PLD. Apart from lighting and TV / radio applications, small-scale businesses have been built in Oeledo with the aim of sustaining electricity supply, such as lighting for kiosks, refrigerators, making handicrafts (sewing, wood carving, etc.), the process of making sugar and support the activities of women's groups in Oeledo. Measures of CO 2 emissions, avoided in the project, were estimated and documented since 2001. and compared with the baseline scenario. The amount and quality of estimated data makes it possible to calculate accurately and in detail about emission reductions. The average CO 2 emission of a diesel power plant is 1.1 kg CO 2 / kWh, the project survey shows that households in remote areas generate an average of 360 kg CO 2 / year in an area. The Oeledo hybrid system can supply community needs of 22,000 kWh per year and tends to increase. This amount of energy results in an avoided emissions of around 24t CO 2 / year. The maximum possible capacity is 44,000 kWh per year, sufficient for future service expansion and changing consumption patterns. The Oeledo hybrid system consists of 22 kWp from the photovoltaic system, 10 kW from the generator generated by wind energy, 20 kW from the diesel generator as a backup, a battery storage capacity of 144 kWh and a 2x20 kW IGBT inverter. The supply of the system is limited, but feasible, to be used to power 120 households, schools, and public places through an additional LV distribution network about 3 km away. The project life of the Oeledo hybrid system is limited by technical factors. The system components have a service life of 10-20 years. The fees collected from electricity customers saved in bank accounts can be sufficient to replace most components over a 15-20 year period. Economic analysis shows that 10-20% of investment can be returned within 20 years, including maintenance costs, management fees and replacement of components after their useful life.

With this project, the people of Oeledo and the state will receive many benefits, including:

• Improve information and communication • Extend productive time for the community • Improve education due to the extension of study time until evening • Improve access to information via TV and radio • In general, from a health perspective, the system creates a cleaner 

environment, reduces the risk of fire, reduces toxic pollution at home due to smoke from kerosene combustion, reduces acute lung infections, and reduces cleaning of equipment - household appliances, bed covers and mosquito net which will reduce the cost of maintaining the house. • Opening new job opportunities and small scale businesses • Creating awareness to use renewable energy technologies • Increasing the electrification ratio in rural areas of Indonesia.

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Hybrid Photovoltaic System and social-economic improvement of Oeledo village communities

Wind and solar power generation is a hybrid technology that is relatively new and environmentally friendly, first introduced by Guiseppe, a doctor from the Italian power company in 1995.

Compared to wind power alone and solar power alone, this hybrid technology is clearly superior because it is not completely depend on the sun. So, if the sky is dark or night falls and the sun disappears, the power plant will be driven by windmills so that the electricity will still flow. Conversely, when the wind is sluggish, the solar cell panels that capture sunlight can continue to supply electricity. This power plant is suitable for areas where the weather changes frequently such as on the coast. This power generation technology is actually not that complicated. It consists of three main parts, namely: Windmill. The panels contain solar cells and electricity storage as shown in the initial Figure. When the wind blows, the blades will rotate the dynamo (dynamo) which generates an electric current. This electricity is then distributed to the storage section in the form of a number of car batteries. At the same time, when the sun is shining the solar cell panels will capture the rays to be converted into electricity as well. This panel contains photovoltaic cells made of two layers of silicon. When exposed to sunlight, the two layers of silicon will produce positive and negative ions, and electricity will be created. Electricity from solar panels and windmills is still direct current (DC). Even though household appliances such as television, radio, refrigerator, etc., require alternating current (AC). For this reason, an inverter is needed, converting the DC current to 220 Volt AC. This power plant can generate 50 kilowatts of power or enough for 600 households, with each family using 450 watts of electricity.

The advantages and disadvantages of wind and solar power plants

Strengths:1. Environmentally friendly2. Practically used in coastal areas3. Does not require special treatment4. The technology is not complicated5. The design is made of materials that are not easily corroded (corrosion)6. Easy to operateWeaknesses:1. It costs quite a lot to purchase and train technical operators2. The availability of spare parts and car batteries is sufficient, especially because it is located far away on the island of

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Efforts To Improve Lighting Protection Performance

The easiest way to improve protection performance is to use more than one ground wire. In this way, it is hoped that the lightning will always strike the ground wire so as to minimize the probability of protection failure. This method can be accompanied by the use of a counterpoise, which is a conductor that is placed under the conduit (more often immersed in the ground) and connected to the grounding system of the electric tower. As a result, the surge impedance will be smaller.

Other efforts include:

Installing a coupling wire under the phase wire (a conductor that is included under the transmission line and connected to the electric tower grounding system).

Reduces the electric tower grounding resistance by using a suitable grounding electrode.

Using arrester.

This last method is arguably the best protective device against surge waves. It is this arrester that continues to be developed by experts to get better protection performance.

Conclusion The overhead

use of overhead ground wire in electric power transmission lines has the hope that the lightning strike does not hit the phase wire. The area of ​​the groundwire protection zone depends on the height of the groundwire itself. The probability of failure in the protection increases as the ground wire increases and the angle of protection increases. For this reason, it is necessary to choose a suitable height and angle of protection to get good protection.

It is easiest to improve the protection performance of electric power transmission from lightning strikes by increasing the number of ground wires. The combination of the use of groundwire with other equipment is expected to obtain a higher protection performance, among others, by using an arrester which is a modern protective device.

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Lightning Protection System

Lightning will strike all objects close to clouds. Or in other words, a tall object will have a great chance of being struck by lightning. The transmission of electric power on land is considered to be more effective using overhead lines by considering its technical and economic factors. Of course these airways would be subject to a direct lightning strike. Moreover, the air ducts that pass through the hills are closer to the clouds and have a greater chance of being struck by lightning.

During a lightning discharge, the cloud's positive charge will induce a negative charge in the power line. This additional negative charge will flow in 2 opposite directions along the line. This surge may damage the insulation of the ducts or only cause a discharge between the channels.

Insulation designs for high voltage (HV) and extra high voltage (EHV) tend to protect lines from overvoltages due to circuit surges and lightning surges. For ultra high voltages (UHV), the insulation design is more likely to be surge protection. The existence of this overvoltage will result in an increase in operating voltage which of course can damage electrical equipment.

In terms of protecting the power lines, there are several ways that can be applied. One of the easiest methods is to use an overhead ground wire in the line. The principle of using ground wire is that the ground wire will be the target of a lightning strike so that it protects the phase wire with a certain area / zone.

An overhead ground wire, which is used to protect the electric power line, is placed at the top end of the line and stretches parallel to the phase wire. These groundwire can be earthed directly or indirectly using short intervals.

In protecting the phase wire, the ground wire protection area can be illustrated as in Figure

Figure 1. Protection area using 1 piece of ground wire. From the picture above, suppose the ground wire is placed as high as h meters from the ground. Using the values ​​in the figure, point b can be determined as 2/3 h. Meanwhile, the ground wire protection zone is located within the shaded area. In this zone, it is hoped that there will be no direct lightning strike so that the phase wires are also stretched in that area. If hx is the height of the phase wire that must be protected, then the width of bx can be determined in 2 conditions, namely: o For hx> 2/3 h, bx = 0.6 h (1 - hx / h) o For hx <2/3 h, bx = 1.2 h (1 - hx / 0.8h)

In some cases, a ground wire is not sufficient to fully protect the phase wire. To improve performance in protection against direct lightning strikes, more than one ground wire is used. If 2 ground wires with a height h from the ground are used and s distance apart, the calculation to determine the lightning protection zone is carried out as if using 1 ground wire. Figure 2 shows the zone of protection from the use of 2 ground wires.

Figure 2.Protection zone from the use of 2 groundwires From the figure, if ho states the height of the point from the ground in the middle of 2 groundwires that are protected from lightning strikes, then ho can be determined: ho = h - s / 4 Whereas the area between the 2 groundwires is bounded by a circular arc of radius 5/4 s with the center point located on the axis in the middle of the 2 

groundwires. As previously mentioned, the presence of groundwire is intended as a place for direct lightning strikes and can protect the phase wire. The protection zone of the groundwire can be expressed by the parameter of the protection angle, which is the angle between the vertical line of the groundwire and the connecting line between the groundwire and the phase wire. If the protection angle is expressed in terms of a and the height of the ground wire is h, then the probability of lightning strike on the ground wire (p) can be determined as follows: log p = - 4

From this equation, it can be seen that the higher the ground wire and the large protection angle, the higher the probability. For this reason, it is necessary to choose the right ground wire height and protection angle to get good protection performance from lightning strikes. Figure 3. Groundwire height curve vs protection angle Figure 4. Protection failure probability curve vs protection angle Figure 3 shows the curve between the mean height of the groundwire vs the average protection angle. From the picture, it can be seen that the black areas are areas of possibility of failure in protection. Whereas Figure 4 shows the probability of protection failure from a lightning strike to the line as a function of the ground wire height and the angle of protection. Thus, the curve in Figure 3 shows the probability of failure in protection of less than 1% (based on curve Figure 4). This probability means less than one failure per 100 lightning strikes on the groundwire. In order to increase the reliability of this system, it is necessary to have proper grounding of each power tower. If lightning strikes on a ground wire near an electric tower, the lightning current will split into two halves. Most of the current flows to the ground through the ground in the tower. Whereas a small portion flows through the ground wire and eventually leads to the ground through the grounding of the next power tower. It is different if the lightning strikes in the middle of the ground wire between 2 electric towers. This lightning wave will flow into the electric towers close to the place of the strike.

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Use of Groundwire Overhead as a Protection for Electric Power Transmission from Lightning Strikes

Lightning is a natural occurrence in which an electric charge jumps between the clouds and the earth. The jump in electric charge begins with the accumulation of water vapor in the cloud. The altitude between the upper and lower surfaces of the clouds can reach a distance of about 8 km with a lower temperature of around 60 oF and an upper temperature of about - 60 oF. As a result, there will be ice crystals inside the cloud. Because in the cloud there is wind in all directions, the ice crystals will collide and rub against each other so that the positive and negative charges are separated.

This separation of charges is the main cause of lightning strikes. The discharge of electric charges can occur in a cloud, between cloud and cloud, and between cloud and earth depending on the ability of the air to withstand the potential difference that occurs.

The lightning that we know today occurs due to clouds with a certain charge inducing a charge on the earth. If the charge in the cloud gets bigger, the induced charge will get bigger too, so that the potential difference between the cloud and the earth will also get bigger. This incident was followed by the descending vanguard from the cloud and followed by the ascending vanguard from the earth approaching the descending vanguard. At that time, what is called lightning occurs. The length of the lightning canals can reach several kilometers, with an average of 5 km. The speed of the vanguard decreasing from the cloud can reach 3% of the speed of light. Meanwhile, the return speed of discharge reaches 10% of the speed of light.

Lightning Protection System

Considering the damage caused by lightning strikes is quite dangerous, there are efforts to overcome lightning strikes. The lightning rod technique was first discovered by Benjamin Franklin using an interceptor (air terminal) connected to a metal conductor to the ground. This technique is further developed to get effective results.

At a glance the lightning rod technique, there are 2 kinds of systems, namely: 1. Lightning Protection System This system uses a pointed metal tip as a charge collector and is placed in a high place so that the lightning is expected to strike the metal tip first. This system has a weakness in that if the lightning current transmission system to the ground does not work properly, then there is the possibility of damage to electronic equipment that is very sensitive to transient fields.

2. Dissipation Array System (DAS) This system uses many point discharge where each point of the object will move the electric charge from the object itself to the surrounding air molecules. This system results in a decrease in the potential difference between the cloud and the earth, thereby reducing the ability of the cloud to discharge electric charges. Lightning Protection System in Electric Power Transmission

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Flash Steam Power Plants

Geothermal in the form of fluids such as natural hot water (hot spring) above 1750 C can be used as a source of generating Flash Steam Power Plants. The hot fluid is flowed into the flash tank with a lower pressure so that hot steam occurs quickly. This hot steam called flash drives the turbine to activate the generator which then produces electricity. The remaining unused heat enters the reservoir back through the injection well. An example of Flash Steam Power Plants is the Cal-Energy Navy I flash geothermal power plant in the Coso Geothermal field, California, USA. 3. Binary Cycle Power Plants (BCPP)

BCPP uses a technology that is different from the two previous technologies, namely dry steam and flash steam. In BCPP hot water or hot steam from production wells never touches the turbine. Geothermal water is used to heat what is called a working fluid in a heat exchanger. The working fluid then gets hot and produces steam in the form of flash. The steam generated in the heat exchanger is then streamed to turn the turbine and then move the generator to produce an electric power source. The hot steam produced in this heat exchanger is known as the secondary (binary) fluid. These Binary Cycle Power Plants are actually closed systems. So nothing is released into the atmosphere.

The advantage of BCPP is that it can be operated at low temperatures, namely 90-1750C. An example of the application of this type of BCPP technology is at Mammoth Pacific Binary Geo-thermal Power Plants in Casa Di-ablo geothermal field, USA. It is estimated that the BCPP geothermal power plant will be increasingly used in the future. The Future of Geothermal Electricity With the increasing need for energy in the world coupled with the increasing awareness of environmental cleanliness and safety, geothermal will have a bright future. The EGS (enhanced geothermal systems) program carried out by the United States, for example, is a massive program to make geothermal as one of the prima donna of power plants in the next 2050.

Indonesia itself actually has a very good chance of utilizing geo-thermal as a power plant, and even has the potential to become an electricity exporting country if it is handled seriously. This is not an exaggeration, considering that there are many geothermal sources that are ready to be exploited along Sumatra, Java and Sulawesi. To facilitate the implementation there is no problem if we cooperate with developed countries as long as our interests are more dominant. For example, we are working with the US Department of Energy (DOE) to obtain various results of their research in EGS. • (Gilbert Hutauruk - SBTI-Directorate General & HR)

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a wealth of Geothermal energy

Within the earth's crust there are times when water flows very close to hot rocks where the temperature can reach 1480C. The water does not become steam because there is no contact with air. If the hot water can come out to the surface of the earth because there are gaps or cracks in the earth's crust, then hot water will emerge which is commonly known as a hot spring. Natural hot water (hot spring) is usually used as a hot spring, and many of them also become tourist attractions. In Indonesia, there are also many natural hot springs that are used as bathing facilities and tourist attractions such as Ciater, Cipanas-Garut, Sipoholon and Hutabarat Villages in Tarutung, Lau Debuk-debuk in Tanah Karo, and several other places throughout the country.

Sometimes the natural hot water comes out as a geyser. In America, about 10,000 years ago, the Indians used natural hot springs for cooking, where the area around these springs is a free area (neutral). Some hot springs and geysers were even sacred to Indian tribes in the past, such as the California Hot Springs and Geysers in the tourist area of ​​Napa, Cali-fornia. Currently, natural heat is even used as space heating in winter, such as in San Bernardino, South Cali-fornia. We can also find the same thing in Iceland (country of Iceland) where buildings and swimming pools are heated with natural hot water (hot spring) which is sometimes called geothermal hot water.

Apart from being a heater, geothermal can also produce electricity. It has been mentioned above that when the natural hot water is mixed with air due to fractures or cracks, besides hot water, steam will also come out. Hot water and steam are then used as a source of electricity generation. In order for geothermal energy to be converted into electricity, power plants are needed. Geothermal reservoirs are usually classified into two groups, namely those with a low temperature (low temperature) with a temperature of <1500 C and those with a high temperature (high temperature) with a temperature above 1500C. The best ones to use as a source of generating electricity are those that enter the high temperature category. However, with technological developments, geothermal sources with a low temperature category can also be used as long as the temperature exceeds 500 C.

Power plants for geothermal power plants can operate at relatively low temperatures ranging from 122 to 4820 F (50 to 2500 C). Compare this with a generator at a nuclear power plant which will operate at a temperature of about 10220 F or 5500 C. This is one of the advantages of geothermal power plants. Another advantage is that it is clean and safe, geothermal is even the cleanest compared to nuclear, petroleum and coal.

Generators used to convert geothermal fluids into electric power generally have the same components as other non-geothermal-based power plants, which consist of a generator, a turbine to drive a generator, heat exchanger, chiller, pump, and so on. Currently, there are three types of geothermal power plant technologies that can convert geothermal energy into electricity, namely dry steam, flash steam, and binary cycle. 

These three types of technology are basically used in different conditions.

1. Dry Steam Power PlantsThis type of generator is the first to exist. In this type of hot steam (steam) is directly directed to the turbine and activates the generator to work to produce electricity. The remaining heat coming from the production well is flowed back into the reservoir through the injection well. This oldest type of generator was first used in Lardarello, Italy, in 1904 where it is still functioning properly. In the United States, dry steam power is still used, such as in Geysers, Northern California.

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Alternatives to Geothermal Power Generation

Indonesia's natural wealth is indeed abundant, from natural resources to mineral resources, all are available. The abundant mineral resources in this beloved country include gold, copper, platinum, nickel, tin, coal, oil and gas, and geothermal. To manage geothermal (geothermal) Pertamina has formed PT Pertamina Geothermal Energy in December 2006. Geothermal is a wealth of mineral resources that has not been widely used. One of our geothermal sources that has great potential but has not been exploited is in Sarulla, near Tarutung, North Sumatra. The Sarulla geothermal source is even reported to have the largest reserves in the world. It was ESDM Minister Purnomo Yusgiantoro who said this when visiting the geothermal location, as published by a local newspaper in Medan several years ago.

Currently geothermal (geothermal) is starting to become a world concern because the energy produced can be converted into electrical energy, in addition to being pollution-free. Several geothermal power plants have been installed in foreign countries such as in the United States, United Kingdom, France, Italy, Sweden, Switzerland, Germany, New Zealand, Australia, and Japan. America is currently even busy with their major research in the field of geothermal under the name Enhanced Geothermal Systems (EGS). EGS is initiated by the US Department of Energy (DOE) and collaborates with universities such as MIT, Southern Methodist University, and the University of Utah. This project is a long-term program where in 2050 geothermal will be the main source of electricity for the United States. The EGS program aims to increase geothermal resources, creating the best and most economical technology, extending the life time of production wells, expanding resources, reducing the price of geothermal electricity to as economically as possible, and having environmental advantages. The EGS program has been active since last December 2005.

The occurrence of Hot Mud and Geothermal

To understand how geothermal is formed, we can analogize the earth with boiled chicken eggs. If we split the boiled egg, we can see the yolk as the bowels of the earth. Then the egg white is the layers of the earth, and the shell is the crust of the earth. Under the earth's crust, the top layer is rocks and hot mud called magma. Magma that comes out to the earth's surface through the mountains is called lava.Every 100 meters we descend into the bowels of the earth, the temperature of the molten rocks rises by about 30 C. So the farther into the earth the temperature of the rocks and mud will be higher. If the temperature on the earth's surface is 270 C then for a depth of 100 meters the temperature can reach around 300 C. For a depth of 1 kilometer the temperature of the rocks and mud can reach 57-600 C. If we measure at a depth of 2 kilometers the temperature of the rock and mud can reach 1200 C or more. Hotter than boiling water that just boils. Even if this mud spurted out, it was still hot. Things like this are happening in Sidoarjo and its surroundings where hot mud is still gushing out.

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Geothermal Power Plant

West Java has enormous potential for geothermal natural resources and is the largest in Indonesia. Geothermal potential in West Java reaches 5411 MW or 20% of the total potential that Indonesia has. Some of the geothermal potential has even been utilized for power plants, such as :

PLTP Kamojang near Garut, has units 1, 2, 3 with a total capacity of 140 MW. The potential that can still be developed is around 60 MW.

PLTP Darajat, 60 km southeast of Bandung with a capacity of 55 MW.

PLTP Gunung Salak in Sukabumi, consisting of units 1, 2, 3, 4, 5, 6 with a total capacity of 330 MW.

PLTP Wayang Windu in Pangalengan with a capacity of 110 MW.

Utilizing geothermal energy is not easy. Geothermal energy, which is generally at a depth of 1,000-2,000 meters below the ground surface, is difficult to predict its existence and "character". Investments to explore geothermal energy are not small because they are classified as high-tech and high-risk. Investments for capacities under one MW range from US $ 3,000-5,000 per kilowatt (kW). Meanwhile, for capacities above one MW, an investment of US $ 1,500-2,500 per kW is required. The next challenge is due to the hot nature of the "site specific" local geological conditions. Production characteristics and production quality will differ from one area to another. A rapid decline in production, for example, is a characteristic of production that must be borne by entrepreneurs or developers, plus poor production quality. can cause a lot of trouble at the generator. For example, a high gas content results in greater investment downstream or in the generation.

In electricity generation, the selling price per kWh set by PLN is considered too cheap so that it is not comparable to the cost of exploration and construction of a Geothermal Power Plant (PLTP). In this regard, PLN cannot be blamed because the basic electricity tariff set by the government is still below the commercial price, which is seven US cents per kWh.

On the other hand, there is geothermal potential in an area, usually in the mountains and in remote areas, which often cannot be utilized because the electricity demand in that area is small so that it is not economical to explore and utilize geothermal energy.

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Microhydro power plant

A hydro scheme requires two things, namely the water discharge and the height of the fall (commonly called the 'Head') to produce useful power. It is a power conversion system, absorbs power from the form of height and flow, and transmits power in the form of electric power or mechanical grip power. No power conversion system can send as much as absorbed minus some of the power dissipated by the system itself in the form of friction, heat, sound and so on. Picture. Head is the vertical height at which water falls. The conversion equation is: Input power = Output power + Loss or Output power = Input power × Conversion efficiency

Microhydro Works

The equations above are usually used to describe small differences. The incoming power, or the total power absorbed by the hydro scheme, is gross power, Pgross. The power that the benefits are delivered is clean power, Pnet. All the efficiencies of the schematic above are called Eo. Pnet = Pgross × Eo kW

Gross power is gross head (Hgross) multiplied by water discharge (Q) and also multiplied by a factor (g = 9.8), so the basic equation for power generation is:

Pnet = g × Hgross × Q × Eo kW (g = 9.8)

where the head is in meters, and the water debit is in cubic meters per second (second (s)). And Eo is divided as follows.

Eo = Civil construction × Epenstock × Eturbin × Egenerator × Control system × E-grid × Etrafo

Typically

Civil construction: 1.0 - (line length × 0.002 ~ 0.005) / Hgross

Epenstock>: 0.90 ~ 0.95 (depending on length)

Eturbine: 0.70 ~ 0.85 (depending on turbine type)

Egenerator: 0.80 ~ 0.95 (depending on generator capacity)

Control system >: 0.97

Grid: 0.90 ~ 0.98 (depending on the length of the grid)

Etrafo: 0.98

Civil and Epenstock constructs are what are usually calculated as' Head Loss (Hloss). In this case, the above equation is changed to the following equation.

Pnet = g × (Hgross-Hloss) × Q × (Eo - Civil construction - Epenstock) kW

This simple equation must be remembered: it is at the heart of all power plant job design. It is important to use the correct units.

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The potential of PLTA Indonesia is 70,000 MW

Indonesia has the potential for hydroelectric power (PLTA) of 70,000 mega watts (MW). This potential has only been utilized around 6 percent or 3,529 MW or 14.2 percent of the total energy generated by PT PLN.

This was stated by the Minister of Public Works Joko Kirmanto and the Managing Director of PT PLN Fahmi Mochtar, during the 2008 National Seminar on the Big Bandungan Besar Indonesia and the Annual Member Meeting of the Indonesian National Committee for Big Dams at the PT Pembangkit Jawa Bali Head Office Hall, in Surabaya, Wednesday (2/7 / 08).

"How many potential water resources are currently untapped and wasted," said Joko in front of hundreds of seminar participants. Then Joko compared it to the countries of the former Soviet Union called the Commonwealth of Independent States (CIS). The combined hydropower potential in CIS reaches 98,000 MW with about 500 dams with a total installed power of 66,000 MW hydropower or about 67 percent of the available potential.

He said that the opportunity for hydropower development in Indonesia is still large, especially since Indonesia is still experiencing difficulties with fuel oil (BBM). Utilization of water resources as one of the primary renewable energy sources can be synergized by utilizing water to increase food security.

How its Good for PLTA

In addition, PLTA is also the answer for power plants that do not produce CO2 such as fossil fuels, although some have accused the increase in atmospheric CO2 due to the construction of dams and operation of reservoirs. Therefore, at the next 10,000 MW energy declaration, it is expected that 7000 of them will come from hydropower. "Indonesia has the fifth highest amount of surface water in the world," he explained.

Joko explained that recently three dams began operating, namely the Kedung Brubus East Java dam, Tibukuning in Lombok and the Pernek dam in Sumbawa. Two other dams are still being built at the Nipah and Bajulmati dams in East Java.

In Central Java, the Gonggong and Panohan dams. Jatigede Dam in West Java, Karian dam in Banten, Benel dam in Bali. In addition, there is the construction of the Beriwit and Marangkayu dams in East Kalimantan, the Ponre-Ponre dam in Sulawesi, in East Nusa Tenggara there is the Haekrit dam and the Keuliling dam in Nanggroe Aceh Darussalam.

The government is also building the Upper Cisokan pumped storage dam in West Java, which is still in the process of approving the design and construction of the PLTA Asahan 3 dam in North Sumatra. The number of dams in Indonesia can still be counted on the fingers. Compare with Saudi Arabia in 2006 and then auctioned the construction of 41 bendingkan.

"The many opportunities to build dams in the country have not been optimally utilized, even though the energy and food security crisis can be resolved by this," he explained.

However, the challenges faced by dam construction include social problems, erosion in the catchment area and sedimentation in the reservoir. As a result, the reservoir's life did not match what was planned. "This is a big challenge that must be resolved simultaneously by various parties," he said.

Meanwhile, the Managing Director of PLN, Fahmi Mochtar, added that the average operating cost per kWh of hydro plants is the lowest compared to other types of power plants, only Rp. 140 / kWh. Currently, PLN manages and operates hydro generator sets on a large and small scale spread across Indonesia.

The number of hydro generating units is 203 units with a total installed capacity of around 3,529 MW and energy production of around 8,759 GWh. PLN said he is encouraging the development of hydro power plants with dams, including the construction of the Jatigede Multipurpose dam, West Java (108 MW), the Kusan hydropower plant, Kalimantan (135 MW), the Upper Cisokan Pumped Storage Hydroelectric Plant dam, West Java (1000 MW), the West Java Rajamandala dam (35 MW ), PLTA Genyem, Papua (20 MW), PLTA Poigor 2 North Sulawesi (20 MW), and PLTA Asahan 3 North Sumatra dam (150 MW)

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The Role of Capacitors in the Use of Electrical Energy

One of the characteristics of modern life is the large consumption of electrical energy. The amount of energy or electric load used is determined by reactance (R), inductance (L) and capacitance (C). The large amount of electricity consumption is due to the large number and variety of electrical equipment (loads) used. While the electrical loads used are generally inductive and capacitive. Where the inductive load (positive) requires reactive power such as a transformer in the rectifier, induction motor (AC) and TL lamps, while the capacitive load (negative) releases reactive power. Reactive power is useless power so that it cannot be converted into power but is needed for the process of transmitting electrical energy to the load. So what causes waste of electrical energy is the number of inductive equipment.

This means that in using electrical energy, it turns out that customers are burdened not only by active power (kW) but also reactive power (kVAR). The sum of the two powers will produce real power which is the power supplied by PLN. If the power value is enlarged, which is usually done by industrial customers, the power losses will be large while the active power (kW) and the voltage reaching the consumer are reduced. Thus production in the industry will decrease, this of course should not happen, therefore the power supply from PLN must be increased, which means additional costs. Because power is P = V.I, increasing the magnitude of power means that there is a decrease in the price of V and an increase in the price of I. Thus, active power, reactive power and real power are a unit which is described as a right triangle in Figure 1.

From Figure 1, it is found that the ratio of active power (kW) to real power (kVA) can be defined as the power factor (pf) or cos r. cos r = pf = P (kW) / S (kVA) ........ (1) P (kW) = S (kVA). cos r ................ (2)

As we know that the price for cos r is from 0 to 1. It means that the best condition is when the price of P (kW) is maximum [P (kW) = S (kVA)] or the price of cos r = 1 and this is also called cos r is best. However, in reality, the price of cos r determined by PLN as the party supplying power is 0.8. So for the price cos r <0.8 means that pf is said to be bad. If the customer pf is bad (low) then the active power capacity (kW) that the customer can use will decrease. That capacity will continue to decline in line with the decline in the pf of the customer's electrical system. As a result of the decrease in pf, several problems will arise as follows:

Increased use of electric power kWH due to losses.

Increased use of kVAR electric power.

The quality of the electricity is low due to voltage drops.

Theoretically, a system with a low pf will certainly cause the required current from the supplier to be large. This will cause power losses (reactive power) and a large voltage drop. Thus a fine must be paid because the reactive power consumption increases to a large extent. Fines or charges for excess reactive power are imposed if the total kVARH usage recorded in a month is higher than 0.62 the total kWH in the month concerned so that the average pf is less than 0.85. Meanwhile, the calculation of excess use of kVARH in rupiah uses the following formula:

[B - 0.62 (A1 + A2)] Hk

Where: B = k VARH usage

A1 = WPB kWH usage

A2 = LWBP kWH usage

Hk = the price of excess kVARH usage

To increase the low cost of cos r (pf) the easy thing to do is to reduce the angle r so that r1 means r> r1. While to reduce the r angle it is possible to do is to reduce the reactive power component (kVAR). This means that the existing inductive reactive power components must be reduced and that reduction can be done by adding a reactive power source, namely a capacitor.

The reduction process can occur because the two loads (inductor and capacitor) are in opposite directions as a result of which the reactive power is small. When the reactive power becomes small while the active power remains, the pf price becomes large, as a result the real power (kVA) becomes small so that the electricity bill is reduced. While other advantages of reducing reactive power are: • Reducing power losses in the system. • There is an increase in voltage due to increased power.

Capacitor Work Process

The capacitor to be used to increase the pf is installed parallel to the load circuit. When the circuit is given a voltage, electrons will flow into the capacitor. When the capacitor is full of charge electrons, the voltage will change. Then the electrons will come out of the capacitor and flow into the circuit that requires it, thus at that time the capacitor generates reactive power. When the changed voltage returns to normal (constant), the capacitor will retain the electrons. When the capacitor releases an electron (Ic) it means the same is ka

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Material Conductor

1.1 Type of Conductor Material

The materials used for conductors must meet the following requirements: 1. The conductivity is quite good. 2. Its mechanical strength (tensile strength) is quite high. 3. The coefficient of expansion is small. 4. The elastic modulus (modulus of elasticity) is quite large.

Materials commonly used as conductors include:

1. Common metals, such as: copper, aluminum, iron, and so on. 2. Alloy metal, which is a metal made of copper or aluminum which is mixed with a certain amount of other metal, which is used to increase its mechanical strength. 3. Alloy metal (composite), which is two or more types of metal combined by compression, smelting or welding.

1.2 Classification of Conductors

1.2.1 Classification of conductors according to their material: 1. ordinary metal wire, for example: a. BBC (Bare Copper Conductor). b. AAC (All Aluminum Alloy Conductor). 2.Mixed metal wire (Alloy), for example: a. AAAC (All Aluminum Alloy Conductor) b. composite metal wires, such as: copper-coated steel wire and aluminum-coated steel wire (aluminum clad steel). 3.mixed wound wire, which is a wire whose coil consists of two or more types of metal, example: ASCR (Aluminum Cable Steel Reinforced).

1.2.2 Classification of conductors according to their construction: 1. solid wire with round cross section. 2. Standard wire consists of 7 to 61 solid wires wound together, usually layered and concentric. 3. a hollow conductor is a hollow wire made to obtain a large outer diameter.

1.2.3. Classification of conductors according to their physical form: 1. bare conductor. 2. an insulated conductor, which is a bare conductor and insulated on the outside according to the designation of the working voltage, for example: a. Twisted cable. b. NYY cable c. NYCY cable d. NYFGBY cable

1.3 Conductor Characteristics

There are 2 (two) types of conductor characteristics, namely: 1.mechanical characteristics, which indicate the physical state of the conductor which expresses the tensile strength of the conductor (from SPLN 41-8: 1981, for 70 mm conductor sheathed AAAC-S at a temperature of about 30 C, then the maximum ability of the conductor to conduct current is 275 A). 2. electrical characteristics, which indicate the ability of the conductor to electric current through it (from SPLN 41-10: 1991, for 70 mm2 conductors sheathed AAAC-S at a temperature of about 30o C, the maximum ability of the conductor to conduct current is 275 A) .

1.3.1 Electrical conductivity The electrical conductivity of a material is expressed in terms of conductivity, which is the opposite of the resistivity or conductive resistivity, where the conductive resistivity is defined as: R. A ρ = ---------- l Where; A: cross-sectional area (m2) l: Length of conductor (m) Ώ: resistivity conductor (ohm.m) R: conductor resistance (ohms) ρ: conductivity

1 a = ------ ρ

Expresses convenience - the ease with which a material can carry an electric current. The unit for conductivity is (ohm meter). Conductivity is an electrical property that is needed in various applications as a conductor of electricity and has a very wide price range. Metals or materials that are good conductors of electricity have an electrical conductivity of the order 107 (ohm.meter) -1 and on the other hand, insulating materials have very low conductivity, which is between 10-10 to 10-20 (ohm.m) -1 . Between these two extreme properties, there are semi-conductor materials whose conductivity ranges from 10-6 to 10-4 (ohm.m) -1. In contrast to low voltage cables, in medium voltage cables to fulfill the function of conductor and safety against use, all three types or properties of conductivity are used.

-------------------------------------------------- ---------------------------------------- Metal Electrical conductivity ohm meter Silver (Ag) ………………………. 6.8 x 107 Copper (Cu) ………………… .. 6.0 x 107 Gold (Au) …………………… .. .. 4.3 x 107 Aluminum (Ac) ………………. .. 3.8 x 107 Brass (70% Cu - 30% Zn)… 1.6 x 107 Iron (Fe) ………………………… 1.0 x 107 Carbon steel (Ffe - C) …………. 0.6 x 107 Stainless steel (Ffe - Cr) …… 0.2 x 107

Table 1. Electrical Conductivity of Various Metals and Alloys at Room Temperature.

1.3.2 Quality criteria of delivery The conductivity of the conducting metal is strongly influenced by the alloying elements, impurity or imperfections in the metal crystals, all of which play a lot in the process of making the conductor itself. The guiding elements, in addition to affecting the electrical conductivity, also affect other mechanical and physical properties. Pure metals have better electrical conductivity than lower purity. However, the mechanical strength of pure metals is low. Conducting electricity, apart from requiring high conductivity, m

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Remembering James Clerk Maxwell (1831-1879)

The famous British physicist James Clerk Maxwell is famous for his formulation of four statements that explain the basic laws of electricity and magnetism.

These two fields had been investigated for a long time before Maxwell and it is well known that there is a link between them. However, although various laws of electricity and magnetism have been discovered and contain truth in several ways, before Maxwell, none of these laws constitute a unified theory. In having four briefly formulated (but highly weighted) sets of laws, Maxwell succeeded in pinpointing the behavior and interrelationships between electric and magnetic fields. In this way he transformed a large number of phenomena into a single theory that could be held on to. Maxwell's views have been widely embodied in the previous century in both the theoretical sector and in the practice of science.

The most important of these, Maxwell's new opinion, is this: many general equations can occur under all circumstances. All the pre-existing laws of electricity and magnetism can be ascribed to Maxwell's opinion, as well as a large number of other laws, which were previously unknown theories. From Maxwell's opinion, it can be shown how periodic oscillation of the electromagnetic field is something that can happen. This back and forth motion like a pendulum is called an electromagnetic wave, which once moved will spread out into outer space. From these opinions it is possible to show that the speed of the electromagnetic waves reaches about 300,000 kilometers (186,000 miles) per second. Maxwell knew that this was equal to the speed of light. From this angle he correctly concluded that light itself consists of electromagnetic waves.

So, Maxwell's opinion is not only a basic law of electricity and magnetism, but also a basic law of optics. In fact, all the preceding laws known as the laws of optics can be attributed to his opinion, as well as many facts and connections to things that were not previously disclosed.

Light that is visible to the eye is not the only kind that allows electromagnetic radiation. Maxwell's opinion suggests that other electromagnetic waves, in contrast to the visible light to the eye in that they have wavelengths and frequencies, could exist. This theoretical conclusion was admirably reinforced by Heinrich Hertz, who was able to generate and encounter the two visible waves to the eye predicted by Maxwell. Several years later, Guglielmo Marconi demonstrated that the invisible waves could be used for wireless communication, thus transforming radio. Now, we also use it for television, X rays, gamma rays, infrared rays, ultraviolet rays are examples of electromagnetic radiation. Everything can be learned through the ideas of Maxwell.

Although Maxwell's most notable fame lies in his tremendous contribution to the field of electromagnetics and optics, he has also made important contributions to the world of science in other areas including the theories of astronomy and thermodynamics (thermal investigation). One of his special interests is the kinetic theory of gases. Maxwell realized that not all gas molecules travel at the same speed. Some are slower, some are faster, and some are at an incredible speed. Maxwell tried a special formula showing the smallest part of a molecule moving (in a certain temperature) at a certain speed. This formula, called the "Maxwell spread," is the most widely used formula in scientific formulas, and contains important meanings and uses in every branch of physics.

Maxwell was born in Edinburgh, Scotland, in 1831. He was developing very early: at the age of fifteen he was able to present a scientific paper to the "Edinburgh Royal Society." He attended the University of Edinburgh and graduated from Cambridge University. Married, but did not have children. Maxwell is generally considered the greatest theorist in the field of physics in the entire time between Newton and Einstein. His brilliant career ended too quickly as he died in 1879 of a cancer attack, shortly after celebrating his 48th birthday.

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Founder of Faraday Law

In the world of electricity, many figures have participated. Call it de Coulomb, Alesandro Volta, Hans C. Cersted, and Andre Marie Ampere. They are considered the best "masters" in the field of electricity. However, from all of that, one must not forget a name that is very meritorious and is known as a pioneer in researching electricity and magnetism. He is Michael Faraday, a scientist from England.

Michael Faraday was born on September 22, 1791 in Newington Butts, England. His parents are classified as poor families. His father was only a blacksmith who had to feed his ten children. No wonder his father could not afford to pay for his children's schooling, including Faraday. To help the family economy, at the age of 14 Faraday worked as a bookbinder and bookseller. In between his work, he uses it to read various types of books, especially natural sciences, physics and chemistry.

When he was 20 years old, he attended lectures given by famous British scientists. One of them is Sir Humphry Davy, a chemist who is also the head of the Royal Institution laboratory. During his lecture, Faraday took careful notes and transcribed neatly back to what he heard. Then he sent the notes to Humphry Davy along with a job application. It turned out that the lecturer was interested and appointed Faraday as his assistant at the famous University Laboratory in London. At that time he was 21 years old.

Under Davy's tutelage, Faraday made rapid progress. Initially, he only worked as a bottle washer. However, thanks to his persistence in learning, in only a relatively short time, he was able to make new discoveries of his own creation, namely finding two chlorocarbon compounds and successfully liquefying chlorine gas and several other gases. Thanks to his cleverness, Faraday was able to connect with well-known experts, such as Andre Marie Ampere. In addition, he also had the opportunity to tour Europe with Davy. On this occasion, Faraday began to build on his practical and theoretical knowledge. Davy had a profound influence on Faraday's thinking and led Faraday on his discoveries.

Faraday's first important discovery in the field of electricity occurred in 1821. Two years earlier Oersted had discovered that the needle of an ordinary magnetic compass could be shifted if an electric current was applied in a wire that was not far apart. From these findings, Faraday concluded that when the magnet is tightened, the wire moves. Working on this conjecture, he succeeded in devising a clear scheme in which a wire would continuously rotate close to a magnet as long as an electric current was applied to the wire. In fact, in this case Faraday had invented the first electric motor, the first scheme of using an electric current to make an object move. However primitive, Faraday's invention is the "ancestor" of all the electric motors used in the world today. Since his first discovery in 1821, Michael Faraday, the self-taught scientist, became famous. The result of his discovery is considered to be the beginning of the study of electricity.

Faraday's Law

In experiments carried out in 1831, he discovered that when a magnet is passed through a piece of wire, a current will flow in the wire, while the magnet moves. This state is called "electromagnetic influence" and this discovery is called "Faraday's Law". This discovery is considered a monumental discovery.

Why? First, "Faraday's Law" has significance in relation to our theoretical understanding of electromagnetics. Second, electromagnetics can be used as a continuous propulsion of electric currents as used by Faraday in making the first electric dynamo. With his various findings, it is no exaggeration if Faraday is one of the figures who has made the greatest contribution to mankind. He is a simple person, an inventor who started learning on his own. He showed simplicity when he refused to be knighted and also refused to become chairman of the British Royal Society. Due to health problems, Michael Faraday stopped researching. However, he continued his work as a lecturer until 1861. He died on August 25, 1867 and was buried near the city of London, England. The Inventor of the Lines of Magnetic Force