Drive protection of oil immersed transformer
2022-11-01
The simple oil immersed transformer is used to change the control circuit. It is equivalent to a switch, and the other is to increase the current.
① Protection control switch: the control switch only controls the on-off of the oil immersed transformer coil, and the force generated by the oil immersed transformer coil is used to on-off the circuit to be controlled by the control switch. After the oil immersed transformer, the control switch only flows through a small coil current of the oil immersed transformer, so the switch is not easy to be damaged and the service life is extended.
② Automatic control: the coil current of some oil immersed transformers is controlled by a certain working voltage in the circuit. When the controlled voltage in the circuit reaches the set operating voltage of the oil immersed transformer, the contact of the oil immersed transformer changes its working state to achieve automatic control. For example, the starter drives and protects the oil immersed transformer. After the engine starts, the generator generates electricity. The midpoint voltage of the generator makes the contact of the oil immersed transformer open, and automatically disconnects the circuit of the starter switch.
(1) The function of preventing the transformer from entering the live compartment by mistake makes the opening and closing of the transformer cabinet door have a locking relationship with the grounding switch, that is, the transformer door can only be opened after the grounding switch is closed. This accident exposed that the "five prevention" mechanical locking device of the old model transformer is imperfect.
(2) Transformer electricity inspection is a problem that has puzzled the safety of electric power production for many years. The mechanical "five prevention" locking device of fully enclosed "five prevention" transformer promoted today cannot meet the requirements of the safety regulations "transformer manufacturers conduct electricity inspection first, and then hang grounding wires". Because during power outage, it must be verified that the equipment has no voltage before closing the grounding switch. However, the closed transformer is in a fully closed state. According to the normal operation method, it is impossible to use the portable electroscope to test the power of the equipment. Therefore, the method of forcibly unlocking and opening the transformer cabinet door appears.
(3) Live display devices with neon lamps as display elements are widely used in transformers. After a long period of operation, it is found that the blindness rate is high and neon bubbles are damaged in large quantities. In order to make up for the defects, neon lamp operation/shutdown switch is installed on the live display device. Normally, the switch is in the off state, so that the whole live display device temporarily exits the operation. In this way, the live display device can not be used to monitor whether the line side is live or not.
(4) The neon lamp has low brightness, especially in the bright environment where the brightness is scoured and the display is poor.
(5) The old type live display device with forced transformer locking has a simple locking principle. It just directly combines the signals output by A.B.C three-phase sensors after half wave rectification to control the locking circuit. In this way, when single-phase grounding or phase loss occurs in the system, the device can not be reliably locked due to the drift of the locking control voltage, which may lead to an accident of closing the grounding switch with electricity.
(6) Most of the neon lamp type live display devices installed are plastic shells and installed in the equipment bay. Once the transformer is short circuited and arced in the operation process, the high-temperature arc may melt the plastic shell of the device and hurt the operation or maintenance personnel.
Qingdao Hengfengyou Electric Group, is an electrical enterprise with transmission and distribution industry as its main business, integrating product research and development, manufacturing and trade. Designated suppliers for the world's top 500 enterprises.Its main products include oil-immersed transformer,dry-type transformer,electric furnace transformer,mining transformer ,rectifier transformer .It has been successfully sold to more than 50 countries around the world. Product certification is complete. Hengfengyou Electric will provide you with the best electrical product solutions. 【https://www.hengfengyou-electric.com ； sales@hengfengyou-electric.com ； WhatsApp：+86158 5325 2696（Jack） +86158 5326 5269（Alisa） 】
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