Protective Measures for Oil - immersed Transformer

Oil-immersed transformers protection measures Oil-immersed transformers should pay special attention to its fire safety measures. 1, when the adjacent two oil-immersed transformers between the fire spacing does not meet the requirements, should be set to fire the top of the wall or fire plus fire water curtain. Single-phase oil-immersed transformers can only be set between the fire wall or fire water curtain. 2, the oil content of 2500kg or more oil-immersed transformers and oil in the 600kg-2500kg between the oil-filled electrical equipment, the fire spacing should not be less than 5m. 3, when the outer wall of the plant and the outer edge of the oil-immersed transformer 37.5kva transformer is less than the provisions of the specification sheet, the wall should use a firewall. The distance between the wall and the outer edge of the transformer should not be less than 0.8m. 4, the outer wall of the plant away from the oil-immersed transformer within 5m, the total thickness of the transformer plus 3m below the horizontal line and both sides of the outer edge of the 3m range should not be set up doors and windows and holes in its range outside the Fire doors and fixed windows, the fire resistance should not be less than 0.9h. 5, 2000 kva transformer and other oil-filled electrical equipment, a single oil in the 1000Kg or more, should be set up oil storage pit and public pool. 6, oil-immersed transformers should be in accordance with the relevant provisions of the existing norms, set up fixed water spray and other fire extinguishing system. Oil-immersed plant transformers shall be located in separate rooms, the doors of which shall be outward-facing Class II fire doors and shall be open to outside or corridors and shall not open to other rooms.

Drying treatment and requirements for box type transformers

Box-type padmounted transformer drying treatment and requirements Box-type transformer repair winding or insulation replacement, the body in the air leakage time exceeded, measured by the insulation resistance of the absorption ratio proved transformer winding moisture, etc. to dry the transformer. Transformer drying treatment common methods are: induction heating method, hot air drying method, oven drying method. 1 pad mount transformer insulation drying standards (1) transformer oil does not contain moisture. Oil breakdown voltage of not less than 75% of factory data. (2) insulation resistance of not less than 70% of factory data. (3) Dielectric loss tangent is not greater than 130% of factory data. 2 Transformer should meet the following conditions should be dry (1) overhaul replacement winding or insulation. (2) In the repair or installation of the body inspection, the body exposed to air for more than the corresponding time. (3) Insulation resistance and absorption ratio measurement proved that the transformer winding damp.

Partial discharge of the transformer is how to produce

Partial discharge is mainly Amorphous Core Transformer, transformers and other high-voltage electrical equipment in the role of high voltage, the internal insulation of the discharge occurs. This discharge only exists in the local location of the insulation, does not immediately form the entire insulation breakdown or flashover through, so called partial discharge. Partial discharge is very weak, relying on human intuitive feeling, such as the eye view of the ear is not aware of, only the high sensitivity of the partial discharge measuring instruments to detect it. Insulation inside the three winding transformer in the operation of long-term under the action of the voltage, especially with the voltage level increases, the insulation strength of the electric field is high, weak in the insulation is likely to produce partial discharge, the partial discharge of the reason is: Too much concentration of a point, or a point of the electric field strength is too large, such as solid medium bubbles, impurities are not removed in addition to the net; oil water, gas, suspended particles; different media combinations, the interface has serious electric field distortion . Traces of partial discharge in the solid insulation often leave only a small spot, or a dendritic burn marks. In the oil, there are some decomposition of the small bubbles.

Work preparation of oil immersed transformer before hanging core

11kv single phase transformer core pre-work preparation: ⑴ tool material preparation: such as storage tanks, oil filter, complete sets of wrenches, Dao Ben, oil-resistant plastic rope, white cloth, paperboard insulation and so on. ⑵ lifting equipment preparation: such as cranes, down chain, lever hoist, tripod, wire rope, etc., if the inverted chain, the 200kva electrical transformer must be based on the height and weight of the hanger. ⑶ transformer oil treatment, oil samples and testing, good oil preparation, including oil filter paper. ⑷ do the preparation of the oil pan, hand release core. The height of the hanger (h) shall not interfere with the ejection of the body. H2 h3 h4 h5 h5 h3 h4 h5 h2 h3 height h2 height of the body h3 hoisting height h4 pulley (or inverted chain) minimum distance h5 standby height (300 ~ 500mm) 1 hanging Beam 2. Pulley 3. Rope sets 4. Body 5.

Dry - type transformer low - voltage outlet mode

1, low-voltage standard closed bus: If the use of closed wiring project bus (also known as plug-in bus or bus-intensive busway), the corresponding high voltage auto load booster provide standard closed bus terminal to facilitate connection with the external busbar.
Enclosure (IP20) products, enclosed on the top cover of the housing provide closed bus flanges; no enclosure (IP00) products, only closed busbar terminals.
2, low-voltage side of the standard side line: when the dry-type transformers and low-voltage distribution panel placed side by side, in order to facilitate the connection between the terminals, transformers can provide low-voltage side of the line, usually with GGD, GCK, MNS and other low- Transformer factory and switchgear factory to sign the interface with the minutes to confirm the detailed size with the interface to ensure the smooth installation of the scene.
3, low-voltage side of the line stand side stand: and the horizontal side of the outlet similar to the elected domino screen and other busbar layout for the vertical 100kva single phase pole mounted transformer of low-voltage distribution screen, the transformer can provide low-voltage stand side-qualifying outlet.
Transformer components include the body (core, winding, insulation, lead), transformer oil, fuel tank and cooling devices, pressure regulator, protection devices (moisture, airway, gas relays, oil conservator and temperature measurement devices ) And outlet bushing.

Protection of dry - type transformers

Usually IP20 protective shell, to prevent the solid foreign body greater than 12mm in diameter and rats, snakes, cats, birds and other small animals to enter, resulting in a short-circuit power failure and other malignant failure, to provide security for the live part of the barrier. If you need to install the 100kva distribution transformer in the outdoors, you can choose IP23 protective shell, in addition to the IP20 protection, but also to prevent the vertical line into a 60 ° angle within the water droplets into. But the IP23 shell will reduce the cooling capacity of the single phase pole mounted transformers, the choice should pay attention to the reduction of its operating capacity

Dry - type transformer wiring

1, pole mounted distribution transformer "input" and "output" terminal with a megger test with the ground insulation resistance. 1000V megger measurement, the resistance is greater than 2M ohms.
2, the transformer input and output power line cross-section wiring should meet the requirements of the current value of the size; in accordance with the 2-2.5A / min2 current density configuration is appropriate.
3, the input and output of three-phase power line should be the transformer wiring board bus color yellow, green, red, respectively, then A phase, B phase, C phase, neutral line should be neutral with the transformer neutral line, grounding line, single phase step down transformer Shell and the transformer center point connected to the usual we said that the ground and the neutral line are derived from the transformer neutral point. (Such as a transformer box should be connected with the corresponding ground box logo).
Check the input and output lines to make sure they are correct.
4, the first no-load power, observe the test input and output voltage to meet the requirements. While observing the machine
Internal abnormal sound, ignition, odor and other abnormal phenomena, if abnormal, please immediately disconnect the input power.
5, when the load test is completed and normal, before access