The method of judging the complete stop of transformer air cooling by using the load current of transformer cooler

Abstract

The invention relates to a method of determining transformer forced air cooling full cut-off by using transformer cooler load current. The method comprises steps that (1) transformer forced air cooling power supply inlet wire current is acquired, and working current of every group of a draught fan and an oil pump is acquired; devices used for measuring current are disposed on the transformer forced air cooling power supply inlet wire and the circuit of every group of the draught fan and the oil pump, and are used to input acquired current values in a transformer forced air cooling control device; (2) when the acquired current value of the transformer forced air cooling power supply inlet wire is equal to the sum of the working current values of the various groups of the draught fans and the oil pumps, normal working continues; when the acquired current value of the transformer forced air cooling power supply inlet wire is zero, and the working current values of the various groups of the draught fans and the oil pumps are zero at the same time, full cut-off occurs. The forced air cooling full cut-off determining is carried out by adopting a way of determining the analog quantity of the transformer forced air cooling power supply, and various defects caused by adopting a way of determining the forced air cooling full cut-off only by using a contactor are solved.

Description

technical field [0001] The invention relates to a method for judging the complete stop of air cooling of a transformer by using the load current of a transformer cooler. 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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