Receiving of transformer oil→sampling and inspection→filtering of transformer oil→vacuum treatment and oil filling→oil hot oil cycle→tightness test and static storage
For the reception of transformer oil, the transformer oil should meet the following standards:
(a) The appearance is transparent, without suspended solids or mechanical impurities;
(b) Acid value after oxidation <0.2mgKOH/g;
(c) Sediments after oxidation <0.05%.
(d) When the temperature is about 40 degrees, the dynamic viscosity is less than 13mm2/s
(e) Water content 220kV<15ppm; 500kV<10ppm
(f) Acid value<0.03mgKOH/g
(g) Ignition point>140℃;
(h) Flash point (closed)>140°C
(i) Gas content <1%
(j) Dielectric strength: 220kVZ40kV/2.5mm; 500kV260kV/2.5mm
(k) breakdown voltage>35kV
(l) Does not contain polychlorinated biphenyls (PCB) and corrosive sulfur dielectric loss tangent tg6<5% (at a temperature of 90°C)
(m) Storage requirements for transformer oil: Transformer oil should be stored in sealed and clean special oil tanks or containers.
When draining oil from the oil tank, connect the oil pipeline, the high-vacuum oil purifying machine will heat the oil temperature by self-circulation, the oil purifying machine will clean itself, use the oil purifying machine to clean the hot oil and flush the oil pipeline, if the inside of the oil storage tank has been scrubbed clean, no need for a transformer Oil flushing, the flushing oil should be stored separately and marked well; after the transformer oil arriving at the site is introduced into the oil tank with an oil purifying machine, a high vacuum transformer oil filtration machine is used to filter the transformer oil. In order to improve the oil purifying machine effect, the oil storage tank should be filtered with Inverted tank oil purifying method, that is, all the transformer oil in one oil storage tank is filtered to another oil storage tank through a high vacuum oil purifying machine, and then filtered from another oil storage tank to the original oil storage tank, such as on-site storage If there are few oil tanks, the self-circulation of the oil storage tank can be used, but the relevant sealing must be done well, the outlet temperature of the oil purifying machine should not be lower than 50°C, and the filtered transformer oil should be tested for oil samples to judge whether the purification treatment of the transformer oil is qualified , the oil sample can be sampled from the oil drain of the sampling valve of the oil purifying machine unit;
Precautions for transformer oil filtration:
1) Fences should be set up in the transformer construction area and warning signs should be hung;
2) Fireworks are strictly prohibited in the transformer construction area, and sodium carbonate dry powder fire extinguishers are equipped on site;
3) Before filtering oil, it is necessary to check whether all equipment and components are reliably grounded;
4) When the oil pipe is connected, it must be tied firmly to prevent oil leakage and leakage;
5) During the period of transformer oil filtration, the on-duty personnel should patrol and check the status of equipment and oil system, and make records;
6) When accepting incoming oil, calculate the total amount of incoming oil, distribute the flushing oil, install it, try to avoid wasting oil, and ensure that the transformer is filled with oil at one time;
7) During the process of transformer oil filtration, the manhole door of the oil storage tank should be sealed with plastic cloth, and the bottom of the added moisture absorber should be filled with enough oil according to the scale line
8) The minimum oil temperature at the outlet of the oil purifying machine is 50°C, and the maximum should not exceed 70°C;
9) Observe the oil quality of the vacuum pump of the oil purifying machine unit, and replace the vacuum pump oil in time;
10) Pay attention to observe the oil level in the oil accumulation window of the oil purifying machine unit, and stop the machine in time to drain the oil;
11) Pay attention to observe the outlet pressure gauge of the filter screen of the oil purifying machine unit, and replace the filter screen in time;
12) When the oil pipe is not in use, it should be sealed tightly with plastic cloth immediately to prevent moisture and impurities from entering the pipe;
13) After filtering the oil in the oil storage tank, seal the outlets of the oil tank tightly with plastic cloth in time;
14) Before the heater of the oil purifying machine unit is put into operation, it must be confirmed that the oil level of the oil purifying machine unit is normal. Before the oil purifying machine unit is shut down, the heater should be turned off to prevent the heater from burning in vain and damage to the equipment.
The preconditions for vacuum treatment and oil injection work are as follows: the transformer oil is dehydrated, degassed and filtered through the vacuum oil purifying machine, and the oil quality meets the requirements.
In the process of vacuuming the transformer, check for leakage at any time. In order to hear the sound of leakage, you can stop the vacuum pump if necessary, find the leakage, and repair it in time. When the vacuum degree is <50Pa, the time to maintain the vacuum degree is not less than The exposure time of the body in the air should not be less than 24 hours; oil filling should be started under the condition that the transformer has no leakage;
After the vacuuming time reaches the requirement, open the valve and inject oil through the vacuum oil purifying machine. During oil injection, the average oil temperature at the outlet of the vacuum oil purifying machine should be controlled at 45°C-55°C. During the entire vacuum oiling process, record the vacuum degree every hour, the oiling start time, stop time, the problems that occurred and the treatment process should be recorded in detail; If the oil level changes, after filling the oil, close the oil filling valve and dismantle the oil filling device, use all components, accessories of the transformer and all the air release plugs of the pipeline to release air, if there is oil overflow, tighten the air release plug immediately, and wipe off the overflowing oil. The rubber pad of the vent plug is relatively small, so moderate force should be used to seal well without damaging the rubber pad.
In order to eliminate dampness on the insulating surface of the body during installation, hot oil circulation should be carried out after vacuum oil filling of transformers of 330kV and above. Main transformer hot oil circulation Before hot oil circulation, the oil pipe should be vacuumed to clean the air in the oil pipe; the oil in the cooler and the oil in the main body of the oil tank should undergo hot oil circulation at the same time; the hot oil circulation should be carried out through a vacuum oil purifying machine, and the whole The vacuum degree of the circulation system (including the transformer) should be kept at <130Pa during the whole hot oil circulation process, and the transformer should not be filled with oil, and the oil surface should be 100mm-200mm away from the top cover; the oil temperature in the oil tank should be maintained at 60°C-70°C, the cycle time must meet the following conditions before it can be terminated: the duration of hot oil circulation should not be less than 72 hours; The oil quality of the transformer oil after the oil circulation should meet the standard requirements when the transformer oil is received.
Add：1 Xinmao Road, Beibei district, Chongqing, China