Transformer oil circulation device with diesel engine power and heat

Abstract

One of the problems faced in using conventional transformer oil circulation devices is their high power consumption, especially when the heaters are in the circuit. Therefore, this invention attempts to provide a new solution for the independence of the oil circulation device from the grid electricity or external diesel generator by using a diesel engine as a dual power source for both the oil and vacuum pumps and as a heat energy supplier for oil heating. In this design, the diesel engine first drives the oil and vacuum pumps, and accordingly, the above pumps will operate without the use of electricity. On the other hand, in order to eliminate electric heaters and thus eliminate the main cause of high electricity consumption of conventional devices, the exhaust heat of the diesel engine is used to heat the oil and bring it to the desired temperature (60 to 65 degrees Celsius). Of course, a generator driven by the same diesel engine is used to supply power to the control systems (command circuits, sensors, protection and control devices, electric valves, etc.) and also to the hot oil pump.

Description

Description of the invention Title of the invention (as stated in the declaration) Transformer oil circulation device with diesel engine power and heat Technical background of the relevant invention This invention is related to electrical power engineering in the field of transformers, and in particular, transformer oil circulation. Technical problem and stating the objectives of the invention Transformers are one of the most important and expensive equipment available in various sectors of the electrical industry and other related industries, and therefore the installation, commissioning, or proper repair and maintenance of transformers is of particular importance. Therefore, one of the main prerequisites in this field is the use of a quality transformer oil circulation device. One of the problems with conventional circulation devices is the high power consumption, especially when all the heaters are connected to the circuit, which, depending on the capacity of the circulation device, can consume up to 200 amperes of three-phase power. Therefore, in this regard, two cases can usually be considered for the transformer installation site: 1- The site has the capacity to supply such current through the mains electricity: In this case, it is necessary to first supply the current to the circulation device using a suitable cable, then supply the required current from the beginning of the oil injection and circulation process until the end of the process, depending on the capacity of the transformer and circulation device, for a period of several hours to several days, and as uninterrupted as possible. 2- The site does not have the capacity to supply such a current: In this case, it is necessary to supply electricity through an external power source such as a diesel generator. Here, too, the required electricity needs to be supplied from the beginning of the oil injection and circulation process until the end of the process, depending on the capacity of the transformer and circulation device, for a period of several hours to several days, and as uninterrupted as possible. Considering the above, it can be seen that one of the main problems facing the use of the circulation device is the supply of the high electric current required, which, if supplied through the network, may cause voltage drops and affect other nearby loads, in addition to increasing the electricity costs of the transformer installation site. If electricity is supplied through a rented diesel generator, in addition to the problems arising from the possibility of providing a suitable diesel generator, it will also involve large costs such as renting a diesel generator from the supplier, transportation costs, cranes for dismantling and reloading, etc. Also, due to the presence of high current, if electrical safety precautions are not observed, improper cable is used, improper cable connection to the power or input terminals of the device, etc. can lead to irreparable accidents. Accordingly, one of the objectives of this invention is the independence of the oil circulation device from an external power source (electrical network or diesel generator), which will be explained in the following sections. On the other hand, reducing energy waste can be considered one of the other goals of this plan, so that if an external diesel generator is used, the energy conversion is as follows: 1- Chemical energy (fuel) to mechanical (diesel) 2- Mechanical to electrical energy (generator connected to diesel) 3- Electrical to mechanical energy (oil and vacuum pumps of the circulation system) 4- Electrical energy to heat (circulation device heaters) Of course, if you use grid electricity, there will be similar energy conversions as above. However, in this invention, despite the inclusion of a diesel engine inside the circulation device, the energy conversion is as follows: 1- Chemical energy (fuel) to mechanical (diesel) 2- Mechanical energy (diesel) to mechanical (oil and vacuum pumps) As can be seen, with the presence of a diesel engine in the circulation system, energy loss will be minimized because the mechanical energy of the diesel engine drives the oil and vacuum pumps, and the thermal energy lost by the exhaust heats the oil. A description of the state of the prior art and the history of developments related to the claimed invention. 1- In the patent Process for treating contaminated transformer oil (US4498992A) (1985) A process for treating contaminated transformer oil is provided which involves heating the oil in a first heater to a temperature between 100 and 125 degrees Fahrenheit, then passing the oil through an absorbent containing fuller's earth with a mesh size of about 30 to 60, and then directing the oil to a chiller and reducing its temperature to about 50 to 70 degrees Fahrenheit. The oil is then directed from the chiller to a centrifuge to remove water and from there to a second heater to increase its temperature to about 100 to 160 degrees Fahrenheit. The oil is then vacuumed to 0.2 to 2 mm Hg for degassing and finally passed through a polishing filter. 2- In the patent Apparatus for removing water from dielectric oil in electrical power transformers (WO2000052445A1) (2000) A device for removing water from oil includes a vacuum pump to remove air from the oil and a capacitive sensor to monitor the amount of moisture dissolved in the oil. 3- In the invention Design and manufacture of on-line physical oil purification device for power transformers (40824) (2007) The above device enables online physical purification of transformer oil, which, like other similar devices, consists of a filter, heater, vacuum pump, etc. 4- In the invention Electrically powered transformer oil physical purification device without switching (94841) (2017) The above device also enables the physical purification of transformer oil in an electrically powered manner, which, like other similar devices, consists of a filter, heater, vacuum pump, etc. Providing a solution to an existing technical problem along with an accurate, sufficient, and integrated description of the invention As mentioned, one of the problems faced by the use of conventional oil circulation devices is their high power consumption, especially when the heaters are switched on. Therefore, this invention attempts to provide a new solution for the independence of the oil circulation device from the grid electricity or external diesel generator by using a diesel engine as both a driving force for the oil and vacuum pumps and as a supplier of thermal energy for heating the oil. In this design, the diesel engine first drives the oil and vacuum pumps, and accordingly the above pumps will operate without the use of electricity. On the other hand, in order to eliminate electric heaters and thus eliminate the main cause of the high power consumption of conventional devices, the exhaust heat of the diesel engine is used to heat the oil and bring it to the desired temperature (60 to 65 degrees Celsius). Of course, a generator driven by the same diesel engine is used to supply power to the control systems (control circuits, sensors, protection and control devices, solenoid valves, etc.) as well as the hot oil pump. The overall operation of the device according to the provided diagram is as follows: In this system, the inlet oil (OI) is sucked by the oil pump (2) and enters the inlet filter (1) and then passes through the heater tank (3) and enters the degassing tank (4) which is under vacuum by the vacuum pump (8). Then the outlet pump (5) directs the oil to the outlet filter (6) and the oil exits from the outlet (OO). As can be seen, the operations performed so far are not much different from other conventional circulation devices, but the basic issue is the operating principles of equipment such as oil and vacuum pumps, as well as the device heater. The necessary explanations in this regard are provided below: A - Mechanical power transmission system: According to the presented diagram, the energy received by the mentioned equipment is not through electricity but through the built-in diesel engine (7). In this way, the diesel engine (7) transfers power (PT) to the oil pumps (2 and 5), vacuum pump (8) and generator (11) through the usual methods such as shaft, belt and pulley, gear, etc. and causes them to function. Also, depending on the performance of the consumers, a permanent connection or a connection with a clutch (automatic or manual) can be used. B - Heat transfer system: According to the diagram presented, the energy received by the heater is not through electricity, but the exhaust output of the diesel engine (7) through a closed heat transfer cycle (HT) using the oil in the hot oil tank (9) causes the heater tank (3) to be heated indirectly. In addition, in the heat transfer cycle, in order to circulate the hot oil, the power transfer (PT) is carried out through an oil pump (10) and the energy required by the pump (ET) is also supplied through a generator (11). It should be noted that the oil in the above cycle is a special hot oil for heat transfer, which is different from transformer oil and is stored in a small oil tank (9). Regarding other alternative methods, the following can be stated: - Due to the fact that the oil circulation device can operate without interruption for several hours to several days, the diesel engine is the most suitable option among internal combustion engines, which is also used in this invention. However, it is possible to use other engines such as gasoline, gas engines, etc. in the circulation device. - Considering the transportation of the device using vehicles such as vans, trucks, etc., it can also be assumed that the combustion engine is placed outside the circulation device. In fact, by making the necessary changes in the vehicle's power transmission system and using a power transmitter that transfers power outside the vehicle's gearbox, it will be possible to transfer power to the consumers of the circulation device. Also, by making changes to the vehicle's exhaust outlet and using a closed hot oil cycle, heat can be transferred to the heater tank of the circulation device. Therefore, in this case, the vehicle carrying the device enters the transformer installation site and stops next to the transformer, then by operating in place and changing the vehicle's power transmission path, the oil circulation device starts working. - It is also possible to use other heat transfer methods, such as direct methods using exhaust heat (without an intermediary), using a heat exchanger, etc. However, considering the sensitivities of transformer oil (absence of contamination and moisture in the oil), the indirect method using a hot oil cycle is preferable. - Considering the capacity and type of transformer and other related technical issues, it is necessary to vacuum the tank of some transformers during installation, commissioning or repair operations at the site, which is done by a vacuum device that includes vacuum and Roots pumps. Considering the design of the transformer oil circulation device with the power and heat of a diesel engine, it is also possible to implement the aforementioned design for the vacuum device. Therefore, considering the much simpler structure of the vacuum device compared to the oil circulation device, using a diesel engine to start vacuum and Roots pumps will not be much of a problem. Explanation of shapes, maps and diagrams Figure 1 shows the overall process of performing oil circulation operations, which includes the following: 1- Equipment: filters (1 and 6), oil pumps (2 and 5), heater tank (3), degassing tank (4), diesel engine (7), vacuum pump (8), hot oil tank (9), hot oil pump (10) and generator (11). 2- Oil enters the circulation device from the inlet (OI) and after passing through various equipment (O), the purified and hot oil exits from the outlet (OO). 3- The vacuum pump evacuates the degassing tank (G) and the gas exits the pump outlet (GO). 4- The diesel engine transmits mechanical power to the oil pumps, vacuum pump, and generator (PT). 5- Closed heat transfer cycle (HT) whose path includes the diesel engine exhaust outlet, heater tank, and hot oil tank. 6- The generator's electrical power (ET) drives the hot oil pump and, as a result, the hot oil circulates (PT). A clear and precise statement of the advantages of the claimed invention over prior inventions. The advantages of this invention over previous inventions are as follows: 1- In conventional devices, oil and vacuum pumps are electric, which makes the device dependent on an external power source (electricity grid or external diesel generator). This invention introduces a device in which oil and vacuum pumps are completely independent of an external power source and are operated by a diesel engine. 2- The highest amount of electricity consumption in conventional devices occurs when, in addition to the oil and vacuum pumps, all the heaters of the device are also included in the circuit. At this time, the electricity consumption can reach up to about 200 amperes depending on the capacity of the device. Providing such a current either requires the necessary infrastructure at the transformer installation site or, if it is not possible to provide the above current by the facilities available on the site, the use of a diesel generator becomes necessary. However, in the device introduced, the basis of the oil heating system is different and instead of using electrical energy, it uses the waste heat of the diesel engine exhaust to heat the oil. 3- Based on items 1 and 2, one of the most important problems of using conventional circulation devices, which is the high consumption of electricity, is solved by using the diesel engine as both a mechanical driving force and a thermal energy source, which makes the device independent of the electrical network or the so-called Off Circuit device. 4- In the introduced device, the amount of energy loss is significantly reduced because the mechanical energy of the diesel engine directly drives the oil and vacuum pumps and indirectly (thermal energy lost by the exhaust) heats the heater. This is while conventional devices use electrical energy supplied from an external diesel generator or the power grid, which requires several stages of energy conversion and consequently increases energy loss. 5- This device has a faster startup speed and lower costs than conventional devices for the following reasons: A) No need for an external diesel generator, and as a result, the elimination of problems arising from the possibility of providing a suitable diesel generator, such as renting a diesel generator from a supplier, transportation costs, cranes for dismantling and reloading, etc. b) No need to supply high current and consequently no need for the presence of a skilled electrician, sometimes long cabling from the power terminals to the device input, increased electrical safety, etc. c) Reducing electricity costs at the transformer installation site, avoiding voltage drops and impacts on adjacent loads, etc. D) If the engine of the vehicle carrying the circulation device is used as a source of mechanical and thermal energy, the speed of starting the device will naturally increase and the costs of performing the circulation operation will decrease. Description of at least one implementation method for implementing the invention One of the most important processes during installation, commissioning or repair and maintenance of transformers is the oil injection and circulation operation, the main purpose of which is to remove moisture, physically purify and degas the oil. During the oil injection or circulation operation, by connecting the bottom valve of the transformer to the inlet of the circulation device, the oil enters the device and after going through the necessary processes, the heated and purified oil is discharged from the outlet of the device and injected into it through the top valve of the transformer. The oil circulation operation lasts from several hours to several days, depending on the capacity of the transformer and the circulation device. Explicit mention of the industrial application of the invention This device is used for oil circulation in all types of distribution, superdistribution, power, power plant, and furnace transformers.

Claims

Claim What is claimed: Claim 1) The transformer oil circulation device with diesel engine power and heat is a device for injecting and circulating transformer oil, which has two main parts: a mechanical power transmission system and a heat transfer system. In the mechanical power transmission system, the kinetic energy of consumers, including oil pumps, vacuum pumps, and generators, is supplied through connection to the diesel engine, and in the heat transfer system, thermal energy for heating the oil is supplied from the exhaust heat of the diesel engine. Claim 2) According to claim 1, in the transformer oil circulation device, it is also possible to use other internal combustion engines, such as gasoline and gas engines. However, due to the device's usually long-term operation, diesel engines have been used among the internal combustion engines. Claim 3) According to claim 1, mechanical power transmission in the transformer oil circulation device is carried out by connecting the diesel engine to the consumers and in accordance with the usual power transmission methods such as shaft, belt and pulley, gear, etc., and also, depending on the performance of the consumers, a permanent connection or a connection with a clutch (automatic or manual) can be used. Claim 4) According to claim 1, heat transfer in the transformer oil circulation device, the transfer of diesel engine exhaust heat to the heater tank is carried out using the closed-cycle hot oil heat transfer method, while it is also possible to use other heat transfer methods, such as direct methods of using exhaust heat (without an intermediary) and using a heat exchanger. Claim 5) According to claim 2, in the transformer oil circulation device, it is also possible to use a combustion engine outside the device, so that by making the necessary changes, the engine of the vehicle carrying the device can be used to transfer mechanical power to consumers and its exhaust heat can also be used to heat the oil.

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