Method for determining full shutdown of air-cooling unit of transformer by using analog value and switching value

Abstract

The invention relates to a method for determining full shutdown of an air-cooling unit of a transformer by using an analog value and a switching value. The method comprises: (1), a current of an air-cooling power supply inlet wire of a transformer, currents of each fan set and each oil pump set, a power bus voltage of an inlet wire of a transformer cooler and a normally-closed contact state of an inlet wire contactor of the transformer cooler are collected; and (2), an air-cooling control unit of a transformer carries out determination of full shutdown of an air-cooling unit of a transformer according to the collected current of the air-cooling power supply inlet wire of the transformer, the currents of each fan set and each oil pump set, the power bus voltage of the inlet wire of the transformer cooler, and the normally-closed contact state of the inlet wire contactor of the transformer cooler. With the method disclosed by the invention, air-cooling full shutdown determination is carried out by determining an analog value and a switching value in an air-cooling power supply of a transformer; and thus various defects caused by single-way contactor-based determination of air-cooling full shutdown can be overcome. And maloperation and operation failure due to air-cooling full shutdown protection setting of a large power transformer can be solved.

Description

technical field [0001] The invention relates to a method for judging the complete stop of air cooling of a transformer by using an analog quantity plus a switch quantity. Background technique [0002] In order to ensure that large power transformers work at the allowable temperature, large power transformers are equipped with forced oil circulation air cooling (referred to as forced oil air cooling). Under the condition of constant load and ambient temperature, once the “cooler stops completely” occurs during the operation of the strong oil air-cooled transformer, the oil temperature will rise sharply, which will pose a great threat to the insulation material inside the transformer, and may cause insulation aging, shock Put on. If it is not handled in time or improperly, it will cause damage to the transformer and a larger power grid accident. Therefore, large-scale forced oil circulation air-cooled transformers are equipped with full-stop protection of the cooler. [0003...

AI Technical Summary

Problems solved by technology

1. Judging that the contactors used are all installed in the outdoor terminal box, and the working environment is harsh, which may easily cause poor contact of the contactors, and may cause the transformer to stop the air-cooled full stop protection and refuse to operate.

2. The contactor is installed near the transformer. Due to the large vibration during operation of the large power transformer, after the contactor and relay are vibrated, the auxiliary contacts are easily closed by the vibration, resulting in misoperation of the transformer's air-cooled full stop protection.

3. After the air-cooled power supply of the transformer fluctuates, the contactor will open and close accordingly, and the air-cooled full stop signal will be sent by mistake

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