Advantages and Disadvantages of Circular and Oblong Cores for Dry Type Transformer This paper analyzes
The power transformer is one of the key pieces of equipment in a power plant. Its operation can directly affect the power generation capacity of the plant and plays a vital role in ensuring the safe and reliable operation of the power grid.
The main problems of power transformer operation and management in power plants are explained in depth, and practical solutions are proposed. The effective measures to ensure the safe operation of power transformers.
At the same time, the causes of common faults such as overheating, abnormal oil level and gas protection faults of power transformers are summarised to provide reference for the safe operation and management of power transformers in the future.
Overheating of the power transformer is one of the common faults in the operation of the power transformer. power transformer often overheats after a long period of work, the reasons for which are mainly the following four aspects.
1) The power transformer is overloaded for long periods of time and is prone to overheating when working with large electrical loads.
2) The cooling device in the power transformer is faulty, resulting in the heat generated during the operation of the power transformer not being dissipated as quickly as possible and the temperature rising continuously.
3) Failure of key components in the power transformer, which results in the power transformer not working properly, resulting in rapid heat generation and rising power transformer temperatures.
(4) Problems with the temperature measuring equipment installed in the power transformer, resulting in the temperature data of the power transformer not being fed back in time and the staff not being able to identify and solve problems with the equipment in time, resulting in the temperature of the power transformer rising. Once the temperature exceeds the specified upper temperature limit, the power transformer is prone to failure.
The normal oil level in the power transformer is crucial for the normal operation of the power transformer and the oil level in the power transformer is mainly determined by means of an oil level gauge.
Generally speaking, there are 3 main reasons why the oil level in a power transformer may be higher than normal.
1) During the installation and maintenance of the power transformer, too much oil is artificially poured into the power transformer, which eventually leads to the oil level in the power transformer exceeding the normal standard.
(2) The cooling system of the power transformer is faulty and the oil inside the power transformer heats up and expands, causing the oil level to rise and not being cooled down in time, resulting in the oil level not being able to drop to its normal position in time.
(3) Some key components inside the power transformer are not working properly, resulting in a higher than normal oil level in the power transformer.
There are 2 main reasons why the oil level of the power transformer is lower than the normal oil level.
1) the power transformer has been overloaded for a long time resulting in serious consumption of the internal oil body, which is not replenished in time, eventually resulting in the oil level of the power transformer being lower than the normal oil level.
2) the power transformer has cracked and other problems causing the oil to leak, resulting in the oil level falling below the normal level.
In the design and manufacturing process of the power transformer, a gas protection system is specially set up, the main purpose of building this system is to prevent safety accidents caused by excessive combustible gases inside the power transformer. gas protection of the power transformer is divided into light gas protection and heavy gas protection.
In general, when light gas protection occurs, it often means that there is a minor equipment failure inside the power transformer, which requires maintenance personnel to overhaul the equipment and remove the fault in a timely manner.
Once the power transformer is heavily gas protected, it means that the power transformer is a major safety hazard, generally because the power transformer is leaking oil and in the process of oil leakage a large amount of gas is generated, which eventually leads to the gas exceeding the standard, which requires staff to immediately The oil pillow explosion-proof door should be inspected immediately, firstly to rule out the internal causes of the power transformer, then to check the external conditions of the power transformer, and finally to check whether the flammable gas inside the power transformer has exceeded the standard. The power transformer should not be restored until all of the above have been checked.
The power transformer also has abnormal sound problems, which are generally caused by two main factors.
1) Due to the power transformer being overloaded, when this fault occurs it will generally make a heavy sound.
When the current and voltage of the power transformer are too high, the power transformer will emit a sharp sound and it is necessary to reduce the supply voltage as soon as possible to avoid further damage to the power transformer.
Power enterprises strictly in accordance with the rules and regulations to carry out equipment operation and maintenance work has long become the industry norm, but if enterprises ignore the construction of the operation and maintenance system, will lead to the system itself is full of loopholes, can not achieve the purpose of guiding the operation and maintenance personnel to carry out work.
The imperfection of the system will lead to the unclear responsibilities of the equipment management department and the operation department, forming a situation where anyone can manage and no one can manage, and ultimately cannot strictly implement regular inspections and cannot efficiently troubleshoot defects and hidden dangers of equipment.
It also leads to operation and maintenance personnel not strictly following the relevant requirements for regular maintenance and overhaul of power transformer equipment, resulting in inappropriate and incomplete overhaul, which threatens the safe and stable operation of power transformer.
Nowadays, many electric power companies implement the “no one on duty, less people on duty” model, streamlining the operation and maintenance personnel, often one person with multiple job responsibilities at the same time, while the lack of power transformer-related skills education and training of operation and maintenance personnel, resulting in the following dilemmas.
1) Lack of maintenance and repair personnel with a high level of professionalism.
In the purchase of new power transformer equipment is generally sent directly by the manufacturer to install staff, later once the equipment failure, enterprises equipped with maintenance maintenance staff can not judge the failure in a timely manner, can only communicate with the manufacturer, the manufacturer sent someone to repair, this situation will greatly increase the power transformer failure when This situation will greatly increase the time of power failure of the power transformer.
(2) Lack of experienced operation and maintenance personnel.
Due to the lack of experience, the operating personnel are unable to find the faults or safety hazards of the power transformer in time, causing the faults to expand and turning small problems into big ones.
Some power enterprises do not have a good understanding of the role of emergency rescue plans for unexpected accidents, believing that “the actual situation is ever-changing, and that the emergency command is more important than the emergency plan, and that emergency management is emergency rescue afterwards”, believing that the emergency plan is only used to cope with inspection and has no practical value.
Safety risks are not identified and assessed in the operation, maintenance and overhaul of the power transformer and the operating environment, nor are changes in various risks due to changes in the operation mode, operating conditions and operating environment (area) of the production system adequately considered, the stock of relevant emergency materials is insufficient, the preparation and review of emergency plans are neglected, and a complete emergency plan management system is not formed. The level of the emergency plan system is not clear enough, the management process is not sufficiently implemented, and the training and drills of the emergency plan go through the motions, coping with inspections more and paying less attention to practical effects.
The current power transformer operation equipment has the characteristics of high automation, but because there is no unified standard for some of the spare parts, resulting in different power transformers may use different equipment, these equipment in the most basic model, performance and other aspects of a certain difference.
The current management of spare parts is often managed separately by the manufacturer, the supplier and the user of the spare parts. In this management mode, it is not possible to ensure that the companies using the spare parts can obtain the spare parts they need in a timely manner.
In order not to affect production, enterprises need to stock a large number of spare parts in case of emergency, however, this increases the cost of inventory, but also occupies the enterprise’s liquidity, reducing the flexibility of the enterprise’s capital.
Although the current power transformer operation automation degree has been greatly improved compared to the past, but in the daily operation still requires manual participation.
A scientific and reasonable operation and maintenance management system is an important guarantee for the normal operation of the power transformer, and with the continuous development of science and technology, the power transformer operation and management system needs to be updated in a timely manner.
A mature and sound power transformer operation and management system is an important guarantee for the normal survival and long-term development of power companies in the future in the face of fierce social competition.
In the regular inspection of the relevant equipment parts, the specific installation and overhaul steps are explicitly stipulated, and staff need to strictly follow the operating specifications when operating to minimise the possibility of human error in operation and maintenance.
(1) Strictly implement the power transformer operation and maintenance personnel first training before starting work system, entrusted with qualified training institutions, the relevant skills training for practitioners. At the same time, establish a perfect mentorship system, so that new employees can master power transformer maintenance skills as soon as possible to meet the job requirements, while improving the theoretical level and training ability of veteran employees.
(2) Strictly implement the system of personnel with a certificate. power transformer operation and maintenance personnel must participate in knowledge and skills training on safety production, and obtain an operating qualification certificate after passing the assessment before they are allowed to start work. more than half a year after leaving work, practical operation training should be conducted.
(3) Establish and improve the training files, record the time, content, participants and assessment results of education and training for operation and maintenance personnel, so as to ensure that operation and maintenance personnel receive adequate training and education.
Before preparing emergency plans for power transformer equipment, analysis and evaluation of accident risk factors and emergency response teams, equipment, materials and other emergency response capabilities should be organised and evaluated, and the plans should be prepared in accordance with relevant laws, regulations, rules, standards and normative documents and strive to improve practicality.
(1) The management personnel should, according to the actual situation, do a good job of power transformer fire disposal plan to ensure that firefighters are able to arrive at the scene in the shortest possible time to deal with fire accidents in power transformer. For some special production equipment fire management should be fine to each step.
(2) Do a good job in the emergency management of power transformer flood control, power transformer flood control work should be placed in an important position.
The necessary flood control equipment and materials must be in place, such as sandbags, pumping machines and so on, to ensure that in the event of a flood, the relevant materials can be used.
Flood control materials should be managed by a dedicated person who can replace expired materials and those that have lost their value, and replenish them with new ones.
After the preparation of the emergency plan, strengthen the training and exercises, training and handover before the exercise, through the training of emergency knowledge into disposal ability.
An effective supply of materials is an effective guarantee for the stable operation of equipment.
The scientific management of the material warehouse can ensure the timely supply of spare parts, establish a computerized material management system, share information on the consumption of spare parts, maintenance and other information, make detailed records of the consumption of power transformer spare parts according to the daily maintenance and regular overhaul of the power transformer, and make scientific calculations, and according to the calculation results Develop a reasonable acquisition plan for spare parts.
The quality, quantity and plan of the spare parts should be kept in the warehouse, and the warehouse management and maintenance staff should open and inspect the boxes together when the parts are received, and contact the manufacturer in time if there is any doubt, so that the spare parts with quality defects do not enter the warehouse.
In terms of storage, it is required to achieve good storage capacity, distinctive markings, and unmixed materials, and to strengthen the maintenance of spare parts, to achieve regular inspection, and to do a good job in the maintenance process to prevent rust, dust, moisture, corrosion, abrasion and deterioration, in order to reduce inventory losses.
When receiving spare parts and accessories, the warehouse system is strictly enforced, and the procedures for receiving materials are standardised and the principles of issuing materials are clarified.
At the same time, the spare parts in the warehouse are often checked against the quantities in the system to ensure that the accounts are in line with the reality.
In the process of power transformer safety inspection, operation and maintenance personnel need to pay special attention to oil leakage, deformation, cracking, wear and tear conditions in the equipment, and if necessary, they can ask professional personnel to come and inspect. When inspecting the equipment, you can use the visual inspection method to check for cracks and rust, the nasal smell method to check for heat in the insulator, and the ear hearing method to check for noise in the operation of the power transformer.
If problems with the equipment cannot be checked directly using the body’s senses, professional instruments can be used to check the equipment.
In some power companies there may be poor inspection of power transformer equipment, resulting in problems that should be detected not being detected in time.
The reason why this situation may occur is, firstly, because the staff is not in place for the implementation of the relevant rules and regulations, and there is the problem of discounting the implementation.
Secondly, the operational procedures for safety inspections are not scientific and reasonable enough, and the areas that should be inspected are not inspected.
In addition, when carrying out power transformer equipment inspections, there is a lack of inspection focus, and the main content of inspections does not change according to changes in weather, load and other actual conditions.
For the above problems need the relevant managers of power enterprises to carry out in-depth analysis and research, find the reasons for them, actively look for solutions, and constantly promote the efficiency and quality of power transformer inspection.
The safe operation of power transformers is not only closely related to the economic benefits of power enterprises, but also to the production and life of society as a whole, so the daily safety management of power transformers is particularly necessary.
To strengthen the operation and management of power transformers, it is necessary to develop a sound management system, improve the professional skills of operation and maintenance personnel, improve emergency response plans and scientifically manage spare parts.
Advantages and Disadvantages of Circular and Oblong Cores for Dry Type Transformer This paper analyzes
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