66kv Transformer Fault Analysis For a 66kV transformer secondary winding deformation fault case, we elaborated
The article examines in depth the economic operation methods of power supply lines and distribution transformers. In the economic operation of power supply lines, power enterprises can take the reasonable selection of line cross-section and the adoption of the parallel process as the entry point; in the economic operation of distribution transformer, power enterprises need to use energy-saving transformers, adopt similar functions, use transformers with low load, improve power factor, choose the correct installation location, reasonably adjust the operating voltage and transformer renewal and other methods to improve the economy of distribution transformer operation.
Currently, the power demand is increasing, the pressure on the power supply is getting bigger and bigger, the power system is undergoing continuous reform, and the competition within the industry is getting more intense. To meet the energy saving requirements, environmental protection, and low carbon energy saving, the power supply field is also continuously optimizing energy saving.
Electricity has become an essential part of people’s lives and production, driving the development of power companies. But there are pros and cons to everything, and the development of power enterprises is no exception. On the one hand, developing electric power enterprises can create higher economic benefits for enterprises.
On the other hand, people put forward higher requirements for electricity, and power line losses, energy consumption, distribution transformers bad losses, and other problems frequently occur, increasing the operating costs and not meeting people’s demand for electricity. In a long period of practice, it has been found that the economic operation of power supply lines and distribution transformers can promote the development of power enterprises; therefore, how to achieve the economic operation of power supply lines and distribution transformers has become a problem that power enterprises have to think about in depth.
The article explores this in-depth, aiming to bring some inspiration to the enterprise, reduce the power line loss, energy consumption, and distribution transformer bad loss while providing protection for its economic operation to bring higher economic benefits to the enterprise.
A distribution transformer is a static electrical apparatus in a power system that transforms voltage and transmits current utilizing the laws of electromagnetic induction. According to the insulation medium, distribution transformers can be divided into oil-immersed distribution transformers and dry-type distribution transformers; according to the regulation mode, they can be divided into non-excited voltage regulating distribution transformers and on-load voltage regulating distribution transformers.
In the power system, distribution transformers are often used for power generation, transmission and distribution.
In the power generation link, distribution transformers can transmit the power generated by the power enterprise to the grid, improve the output voltage of the power plant, and ensure that the output voltage meets the rated high voltage requirements of the transmission power grid In the transmission power link, distribution transformers can transform the voltage to meet the needs of the grid and provide security for the transmission of power.
In the distribution link, the distribution transformer can reduce the end voltage of the transmitted electricity and ensure that the voltage matches the requirements of the distribution grid.
Power supply lines are lines for the transmission of electrical energy. They transmit and distribute electrical energy and connect the power grid to form an electrical system. If there are problems with the power supply lines, they will not only directly impact the transmission of electricity. Still, they may also cause safety accidents and threaten people’s lives and property security.
Power supply lines can be divided into overhead lines and power cable lines. The components of overhead lines include conductors, insulators, earth wires, gold fittings, towers, foundations, etc.; cable lines are usually composed of power cables and cable joints.
The study found that poor management effectiveness is the root cause of power line losses, energy consumption, and alarming losses in distribution transformers. The economic operation of power supply lines and distribution transformers means that companies pay close attention to management and significantly improve the management effect.
Power supply lines and distribution transformers are an essential part of the power system and are closely related to the economic efficiency of the enterprise. Economic operation methods means a substantial reduction in power line loss, electrical energy loss, and distribution transformer terrible loss, which can make the operating costs of enterprises significantly reduced, thus creating higher economic benefits for enterprises.
Cost and economic efficiency are the core competitiveness of enterprises. At present, electricity plays a vital role in people’s life and production, and power supply lines and distribution transformers can directly impact the cost and Economic operation methods efficiency of electricity. Their economic operation can improve enterprises’ core competitiveness, thus promoting power enterprises’ development to a certain extent.
3 Methods for the economic operation of power supply line
Line cross-section and power supply line loss are closely related; want to reduce power supply line loss, it is necessary to make a reasonable choice of line cross-section. Specifically, if the line cross-sectional area meets the specified requirements, the power network design will be scientific and practical, thus reducing the line resistance and significantly reducing energy losses.
The selection of line cross-section needs to be controlled within a specific range; line cross-section once beyond the field, its material loss and input costs will increase, and line construction will also be affected by this.
Currently, the standard line cross-section selection method for the wire density selection Economic operation methods. Compared with other methods, it has the characteristics of careful consideration, can ensure the best line efficiency and operational quality, achieve the economic operation of the power supply line, and lower costs.
Specifically, the wire density selection method takes into account the link between cross-sectional area and resistance, as well as capital costs, annual operating costs, and metal consumption. When using this method to select the line cross-section, the process is as follows:
Take a power company as an example, and its wire economic current density data are as follows.
(1) Copper wire material.
If the use of the length of 3 000 h or less, the current economic density of 3.00 A/mm2; if the use of 3 000 ~ 5 000 h, the current economic thickness of 2.25 A/mm2; if the use of 5 000 h or more, the current economic density of 1.75 A/mm2.
(2) Aluminium wire material.
If used for less than 3 000 h, the current economic density is 1.65 A/mm2; if used for 3 000 to 5 000 h, the current economic density is 1.15 A/mm2; if used for more than 5 000 h, the current economic density is 0.90 A/mm2.
After determining the line cross-sectional area, tests and calibrations need to be carried out to ensure that they correspond to the actual situation and that the purpose of economic operation can be achieved. When carrying out tests and calibrations, the following aspects are required.
(1) Heat conditions: place the wire in a higher temperature environment to see if it can operate normally and if there is any burning phenomenon.
(2) Mechanical strength: Use various instruments to pull the wire to ensure that external forces do not make it appear to be pulled off.
(3) Power line loss, power loss calibration: to monitor the operating supply voltage, and based on the debugging calibration’s monitoring results, to ensure the wire supply voltage and the specified level.
Parallel operation is one of the ways to reduce the losses in the supply lines, which means supplying the same power source and receiving hot spots. There are two common ways of parallel operation.
One is to widen the equal cross-section between the same power source and the receiving hot spot.
The other is to add an unequal cross-section line between the same power source and the hot spot. Companies can adjust the parallel operation method according to the actual situation.
The development of power enterprises has led to the development of related industries, and energy-efficient transformers have emerged. Compared with other transformers, energy-saving transformers use advanced technology and materials and reduce energy consumption.
The easiest and most effective way to achieve the economic operation of distribution transformers is to use energy-efficient transformers. Energy-efficient transformers with low energy losses and a solid technical level must be selected to achieve energy saving and consumption reduction.
At present, China’s urbanization is gradually accelerating, and many farmers are choosing to go out to work, leading to significant differences in population distribution in different parts of the country, with the urban population far exceeding the rural population, which makes transformers in more areas run at low loads for a long time. As the overall energy consumption of the transformer does not change according to the load level, this leads to the phenomenon of energy consumption and the inability to maximize the utility of the transformer.
To solve this problem and achieve the economic operation of distribution transformers, transformers need to be investigated and replaced with transformers operating at low loads.Economic operation methods
The application of parallel operation, i.e., the simultaneous use of 2 distribution transformers, enables the economic function of distribution transformers. Parallel operation is usually used when the line load is high. If a similar process is used when the load is low, this may lead to a significant loss of power.
In the early days, improving the power factor meant increasing the load factor of distribution transformers by using a centralized compensation mode.
However, with the development of the times, the power system has become more complex, electricity has become an indispensable part of people’s lives, and production and the amount of electricity consumption load have dramatically increased.
At the same time, with the increase in population and the widespread use of high power-consuming equipment, the previous methods of improving power factors have gradually become insufficient.
To solve this problem, power companies began to optimize distribution transformers.
In the beginning, people applied distribution transformers with a low level of technology, mainly using manual throwing and cutting methods, which had specific problems, and their internal capacity and branching methods could not match the actual demand.
Later on, the relevant researchers proposed the automation of distribution transformers and tried to modify the capacitor cabinets to make them automatic compensation-type cabinets.
However, the lack of funds and certain shortcomings in the relevant research led to the concept not being implemented.
Then later, it was discovered through research and practice that the addition of reactive power compensation capacitors in large power companies could improve the power factor.
Therefore, reactive power compensation capacitors can be used as an entry point. When reactive power compensation capacitors are used, they need to be automatically put in and fully contacted when the motor stops running.
The location of the distribution transformer can have a direct influence on its operation. If the distribution transformer installation is faulty, the low voltage supply radius will be too long in practice, and the losses in the network will increase significantly.
Over time, it has been found that the best location for distribution transformers is usually the load center of the grid. When installing distribution transformers, the installation location needs to be determined scientifically about the actual situation of the distribution system. After installation, it is necessary to carry out the commissioning required to ensure that its lines are connected correctly and that the supply radius is reasonable so that it can function stably and avoid increasing grid losses.
The operating voltage is closely related to the energy loss of the distribution transformer. To reduce the energy loss of the distribution transformer, reasonable adjustment of the operating voltage can be used as an entry point.
In general, the operation of transformers has its rated voltage range. In the installation and commissioning, the actual operating voltage needs to be increased within the rated voltage range to avoid an over-voltage operation, minimize its energy consumption and achieve economic operation under the condition of ensuring regular operation.
All equipment is subject to losses during operation, and distribution transformers are no exception. The losses in distribution transformers are either visible or invisible. Both need to be placed in the same position of importance when carrying out loss elimination to achieve economic operation of distribution transformers.
It has been found over a long period that losses can only be eliminated if the distribution transformer is continuously updated. The types of distribution transformers are diverse, and there are differences in the renewal cycles of different types of distribution transformers.
Currently, there are two methods for calculating the renewal cycle of distribution transformers: renewal according to the natural life of the equipment as specified by wear and tear; renewal according to the economic life years of the equipment.
There are specific differences between new and old distribution transformers in terms of active and reactive power, and they can increase costs and recovery years.
To achieve economical operation of distribution transformers, when transformer replacement is carried out, it needs to be done before the renewal cycle.
In response to the problem of distribution transformer manufacturers neglecting renewal, the relevant national authorities have made explicit provisions for a renewal cycle of 20 years. This means that, usually, distribution transformers have a service life of 20 years, which can be taken as the standard for distribution transformer renewal.
To sum up, to reduce the loss of power line, energy consumption, and distribution transformer, power enterprises must think deeply about the problem to achieve the economic operation of power supply lines and distribution transformers.
Its operation with the power system, enterprise economic efficiency, management effect, and enterprise development is closely connected.
The economic operation of power supply lines and distribution transformers and their maximum effectiveness can reduce the operating costs of power enterprises while bringing them higher economic benefits, ensuring that they have strong core competitiveness and enabling their long-term, stable development.
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