Online Transformer Oil Filtration unit
Why need an online transformer oil filtration unit?
The power transformer is the core equipment of the power system, the transformer oil as the insulation and cooling medium of the transformer, its performance directly determines whether the transformer can safely run. The main reason for the drop in oil dielectric strength value is the increase in the dielectric loss value and particles in the oil. The traditional treatment method is to take the transformer out of service and use a plate press oil filter unit to clean the transformer oil for 7 to 10 days, while the transformer oil needs to be heated to 65°C. As the plate and frame type pressure oil filter is an open structure, the oil filtering process is in contact with oxygen and the water and gas content in the oil increases significantly. However, this method of oil filtration takes a long time for the main transformer to go out of service, which seriously affects the availability of the main transformer and requires a lot of manpower and material resources. Therefore, there is a need to develop a device (online transformer oil filtration unit) that can filter oil with electricity to reduce the main transformer power outage time and reduce the cost of oil filtering.
What is composition of online transformer oil filtration plant?
ASSEN DVTP Oiline Transformer Oil Filtration Plant includes the main part of the oil purifier machine and the control, protection system. The main part of the oil purifier machine mainly consists of the oil discharge pump, vacuum pump, oil degassing tank, precision filtering tank and inlet and outlet oil condition monitoring device.
The oil filtration unit has a complete control and protection system, including power supply phase sequence protection, current and voltage monitoring, vacuum system monitoring, negative pressure monitoring, cartridge pressure monitoring, oil flow monitoring, oil flow rate monitoring, oil gas production monitoring and positive pressure monitoring. The monitoring system reports the test data in real time and alarms or automatically stops when abnormal.
What problems do I need to solve in filtering process with an online oil filtration unit?
(1) Ensure that the transformer has sufficient safe distance to access the oil filtration pipeline in the charged operation state. The oil purifier machine inlet and outlet ports are designed at the vacuum valve at the top of the oil tank and at the oil drain valve at the bottom of the oil tank respectively, with a safe distance for powered access. The oil purifier machine inlet and outlet ports are distributed diagonally on the main transformer body so that all transformer oil is circulated and filtered as far as possible.
(2) The whole process of oil filtration transformer oil must not come into contact with air, must not produce gas, as well as to prevent suspended air bubbles from entering the transformer internal partial discharge causing the main transformer to trip.
The following design have been adopted for this purpose.
- Vacuum Evacuation. When the oil purifier machine is connected to the transformer, the overall oil filtering piping and oil tank should be vacuumed before opening the valves at the top and bottom of the transformer tank to effectively prevent air from mixing with the transformer oil.
- Positive Pressure System. During the entire oil filtration process, the oil filtration system is a positive pressure system, which effectively prevents air from entering the oil filtration device and piping. After the vacuum standard has been reached, the top and bottom valves of the transformer tank are opened and the oil filtration system is filled with transformer oil.
- Protection System. During the oil filtration process, abnormalities in the oil filtration system can be collected and used as a timely alarm or shutdown. It acts as the last line of defence for the oil filtration system to prevent air from entering the transformer.
(3) To ensure the safety of the filter element and prevent it from breaking and contaminating the transformer oil. The design of the filter element can withstand 1.5 times the working pressure, the main filter canister filter element to assume the main filtering task, its filtering impurities are more, there is a risk of breaking due to excessive pressure, so the design of secondary precision filter canister, to prevent the main filter canister damage impurities directly into the transformer body, at the same time in the oil filter system, the oil outlet and the main filter canister are designed with pressure monitoring devices, can overpressure alarm or shutdown, multiple measures This prevents damage to the filter element and contamination of the transformer oil.
What are the advantages of online transformer oil filtration?
Impact on the reliability of the power supply system
The traditional method of oil filtration with power outage requires transformer power outage for about 10 days, which seriously affects the reliability of the power supply and may result in forced power outage for customers with a large load on the main transformer. Online oil filtration unit does not require a power outage and can be carried out immediately after discovering the transformer oil insulation problem, with no impact on the power supply system.
Difficulty of the filtration operation
The traditional oil filtration method requires large capacity oil storage tanks and large mechanical equipment such as vacuum oil filtering machines, and the safety measures at the construction site are complicated. The online oil filtration unit does not need other auxiliary oil filtering facilities, the oil filtering process is simple, the construction area is small, and less manpower and material resources are invested.
Labor consumption
Conventional oil filtration requires 24/7 manning for 9 days and changing the adsorbent filter paper every 6h, which is labor intensive. The new adsorption cartridge is used for online oil filtration machine, which can process oil from 10% (90°C) to 0.01% (90°C) in one go without the need to replace the cartridge. The operation and information can be monitored remotely, eliminating the need for manning the site and greatly reducing the oil filtration workload.
Filtration effect
The oil filter system pipeline is vacuumed and the whole system forms a closed loop filtration, the oil is not in contact with air, the water in the oil before treatment can be absorbed by the adsorption cartridge, and the micro water content after treatment is reduced. Online oil filtration unit can achieve the effect of reducing oil dielectric loss, reducing oil acid value, increasing oil volume resistivity, increasing oil flash point, removing copper ions in oil and removing corrosive sulphur in oil