Monitoring of a Large Electrical Generators Activity - Research Paper Example

Introduction The behavior of a large electrical generator was monitored continuously to record the performance and the integrity of the device. There are many parameters that have been measured. In this paper, I present the interpretation and analysis of the above results. All large electrical generators use the basic principle of Faraday’s law. To achieve the principle of electromagnetism, the generators have to keep rotating around a magnetic field around a conductor so that current is induced into the conductor, thereby, resulting in an AC current. For this experiment I chose large generators that are used in power generation. These types of generators are characterized by the type of coolant that is used; we have the ones cooled by hydrogen, air, and liquids. However, in this experiment, we used hydrogen coolant generators. There is a number of factors to consider here, first, the insulator medium has to be put into consideration. Coolant Flow Four hydrogen coolers exist in this particular generator. They exist in a veridical position in the frame of the generator. Two of the coolants are positioned at the end of the generator frame while the other two are placed at the axial centre line of the generator. It is possible to take out one coolant while the rest remain performing. To monitor the hydrogen flow in the coolant, a pressure machine is inserted in the inlet position to detect the amount of hydrogen that goes into the coolant and the amount of hydrogen that comes out. The machine is small enough to fit into the inlet while giving enough space for the hydrogen to flow without affecting its flow. There is also another reinforced fabrication at the end of the shield that is made to be able to accommodate the pressure that comes from the hydrogen gas used in the cooling. There were four tests carried out, one at each coolant, which were then recorded. Every test is recorded to know the exact amount of hydrogen flowing into the coolant at any specific time. This test was repeated ten times to observe the consistency of the generator performance. It is important to note that the more time it takes to record the information, the more accurate it becomes, since there is a rise in temperature as time goes on. To be more effective, each test is carried out at the same output load, meaning that the amount of current that is given out is kept constant without changing. This ensures that the information recorded is fair enough for the four coolants. Another important thing to be kept constant is the fuel supply during the test. For each coolant test, the fuel has to be maintained at the same rate so that there is no instance where the fuel is higher than in other parts resulting in more activity in one coolant as compared to the other coolants. In addition, all the coolants have to be in proper working conditions to ensure that there is no unsteady flow of the coolant due to a mechanical problem in any of the coolants. The following table represents the information on the amount of hydrogen coolant that was recorded to enter the coolants in a given minute. Time hours Amount of hydrogen in M3 0 0 1 3 2 7 3 14 4 24 5 32 From the above table, it is important to know that as the time increases so does the amount of hydrogen coolant that goes into each coolant increase. This is because as the time goes on, the amount of heat that is generated increases to a higher level. This comes due to the increase levels of ac output that is observed in the generator. At very high hydrogen intake, the amount of power output is increased by about 10%. Hydrogen is also used as a coolant because of its higher heat transfer. Coolant Pressure Hydrogen was used as the coolant in the generator. To measure the coolant pressure, we have to know the pressure at which the hydrogen gets into the each coolant and the pressure at which it gets out of each coolant. After these measurements are recorded, we compare the pressure of each coolant in relation to the time that the generator is kept running and the amount of AC current that is given out at any given time. At the beginning of the experiment, it is observed that there is less pressure but as the time goes by, there is a significant increase for pressure that the coolant has. This is also followed by a higher rate of hydrogen sucking into the coolants. One of the most important points to note here is the dew point. This is the temperature at which the moisture in the coolant turns into liquid water. We have to always remember to have the lowest dew points since an increase in the dew point can lead to the generator spoiling. Many experiments suggest that if a generator works with a higher hydrogen dew point then it has a higher chance of degradation as compared to a generator that works at lower dew point temperatures. In this experiment, the table below shows how the hydrogen pressure increased with time; the dew point that was recorded at that particular time. Time in hours Hydrogen pressure in bars Dew point in K 0 2.9 33 1 3 34 2 3.2 35 3 3.3 36 4 3.3 36 The above graph represents the relationship between the dew point of the hydrogen gas and the hydrogen pressure as the coolant. At increased pressure of the hydrogen coolant, it becomes denser and in return improves its ability to remove by absorbing heat at the coolants. This leads to an increase in the kilovolt-ampere input and output by about 2%. When the pressure is increased to about 15 to 30 psig the amount of AC output also increases by 0.5%. Vibrations at each of the two bearings As the generator performs, there are vibrations that occur at the two rear bearings of the generator. With this type of vibrations, I placed an alarm at the 11mms so that, when the energy released, to fall to 11mms, then an alarm bell would sound. In the other end, 18mms was set to be the trip that the vibration could take back and forth in the two bearings. With a running speed of about 50Hz, the predominant frequencies were the second and the first harmonic of the 50Hz set by the running speed. To monitor the frequencies, a microscopic computer controlled ticker timer was placed between the trips. This was used to measure the first and the second harmonics based on the running speed. To be more specific, the first harmonic is recoded with one machine while the second harmonic is recorded with another machine. Taking the funder mental frequency of 50Hz the first harmonics is found tot bee 50Hz and the second harmonics 2f definitely falls into 100HZ. However, experimental outcomes show that there is a slight difference in this level. There are about 10% instances when the first harmonics changes to 45Z meaning that the second harmonic will be 90Hz a 10% decrease in the funder mental frequencies. During this time of the vibrations, the power output was recorded to see how the amount of frequency relates to the power output. The table below represents the first harmonics, second harmonics, and the total power output. First harmonics Second harmonics Ac voltage output 50Hz 100Hz 1Kv 45Hz 90Hz 0.9Kv 40Hz 80Hz 0.8Kv 55Hz 110Hz 1.1Kv 60Hz 120Hz 1.2Kv The table below shows that an increase the frequencies of vibrations lead to a general voltage increase at the output. This is because as the vibrations increase so does the number of times that the conductor cuts through the magnetic field is increased; this leads to a higher output at the voltage output. To better the performance of the generator, the vibrations should be monitored to effectively maximize the power output of the generator. A reduced power output from the generator results from low frequencies of vibrations as the conductors does not get many turns around the magnetic fields. When the frequencies are increased, then there is an increase in the power output from the generator. Oil Temperatures Oil temperatures are very important in the determination of the amount of voltage output at the generator output. To determine the oil temperature we have to have an oil temperature gauge. This is a type of thermometer with mercury as the liquid that is useful in showing the temperature values. The measurements have to be done at the inlet as well as the outlet. At the inlet, we have to directly insert the thermometer, which has to be mercury thermometry inside and then record the measurement. The type of thermometer to use has to have the capability of measuring higher temperatures of up to 300K. This is to allow it to accommodate the higher amounts of heat that exist in the inlet and outlet. These temperatures have to be measured at exact time intervals to note the temperatures of the oil as the generator is in working conditions. Diesel is the oil that is to be used here and the temperatures have to be recorded in Kelvin measure. The oil-measuring gauge always has a measuring of 40-320K scale gauges. This scale allows for extreme is placed just in case there is a mechanical problem. During the measuring period, we have to be careful not to take any burns from the oil since the oil can sometimes be hot. The level of the oil also has to be looked. We have to maintain the oil temperatures at around the centre of the tank. Very small amounts of oil will exaggerate the tortures while having excess will also make the tortures to change. There should be no more oil added during the measuring time as this will reduce and finally affect the results. Below are some of the oil temperatures that were taken at the inlet and the outlet of the oil tank. Inlet temperatures in K Outlet temperatures in K 33 58 35 60 37 63 39 70 From this, the average work that is given out between the two bearings is around 30Watts. This is the difference between the outlet temperatures and the inlet temperatures. Stator Temperatures When measuring the stator temperatures of this generator, we have to remember that the distribution of stator temperatures is not even. Therefore, we have to make sure that all stator temperatures of the generator are measured. We do this by placing a number of PN junction sensors at the walls of the generator. This ensures that all the temperatures of the various parts of the generator are converted into a voltage state that the computer can understand. To amplify the voltage, we have to pass the converted voltage in op-amp to make sure that it is amplified to levels that can be interpreted. After the computation, the voltage is then converted into a digital signal that is then transmitted to various parts of the remote communication where we get to read the results in output computer hardware. The measuring here is computerized and well organized such that if any abnormalities are detected then they are instantly transferred to the computer for verification. The stator temperature range always range below 120K. Above this is considered abnormal and below this is not normal. The steps to follow have to be systematic and no steps should be skipped. First, you have to place the various electrical pn junction sensors at strategic locations in the oil tank and the walls of the electrical generator. We also have to ensure that there is no exposure to any liquid. We then connect the pn junction sensors to the op amp, which are then connected to a proper computer output. The results that come from the computer have to be analyzed using appropriate software has to ensure that there is no abnormalities before any conclusion is made. Rotor Temperatures To get the rotor temperatures, we have to know the thermal coefficient of the motors in the generator. First, we use the temperature gauge that we used to measure the oil temperature. After this, the temperatures are measured and recorded in a place for later use. We have to measure the winding voltage by using the brushes of this instrument. After this, we have to look for the hot spot temperature we get this by measuring the conductor temperatures as the oil leaves the output letting and the inlet temperatures of the oil. The type of formulae to use has to be dependent on the type of conductor that is to be used and the configurations used. Rotor temperatures are calculated by multiplying the resistance of the material used to make the generator by the thermal coefficient of the material. The result is the rotor temperatures, which in most cases does not exceed 200K. When they go past this value, then it is considered abnormal and very low temperatures indicate that there is a mishap penning. There are several factors that are to be considered during the measurement, first we have to make sure that the maximum temperatures as well as the lowest temperatures are known and recorder. Another important factor to consider is the acceleration and the deceleration of the motor. When the motor accelerates, it undergoes a series of temperature controls that leads to the resultant decrease in the temperature. When it decelerates, the rotor temperatures also increase contrary to the expectations. For convenience purposes, we can use the DX advanced paperless computer recorder. The inputs are reliable and we have a higher level of accuracy if we use this method. It is also able to measure the ac, the rotor resistance as well as the ac. It also has the following advantages. 1. They can improve accuracy in the digital calculations. 2. It has an adjustable filter for noise. 3. It is able to replace and isolate any existing amps. Conclusion From this paper we are able to know the various ways that we are able to measure the various parameters that are very important in the behavior and performance of the large electrical generator. The generator also has to be in proper working conditions when the measurements are made otherwise most of the measurements become faulty. It is significantly important that as we do the measurements, we increase the amount of samples to do we do not have to restrict ourselves to any specific number of samples to be made rather we have to be able to perform different levels of test. Bibliography SHEETS, W. J. (1987). Electric generators. Palo Alto, Calif, Electric Power Research Institute. EHSANI, M., GAO, Y., & EMADI, A. (2010). Modern electric, hybrid electric, and fuel cell vehicles: fundamentals, theory, and design. Boca Raton, CRC Press. KENAN, G., et al. (2009). City of Ember. Beverly Hills, Calif, 20th Century Fox Home Entertainment. SHOPWARE (FIRM). (2008). Electric generators. Princeton, N.J., Shopware. PARSHALL, H. F., & HOBART, H. M. (1900). Electric generators. London, Offices of "Engineering". ELECTRONIC INDUSTRIES ASSOCIATION. 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