The Studies On Large Direct Current Transformer Based On Hall Effect

The studies n direct current measurement are presented in this dissertation, A kind of Hall effect direct current transformer is developed through many experiments and theoretical analysis. This kind of CT can nieasure direct curl ent up to 1 2000A, the output voltage ratio can be adjusted and the highest output can reach to 1 5V, the linearity is superior to 0.5%. The C]?had passed the final design test and will bring into service on Beijing subway direct current protection project. Direct current is widely applied on subway, electric railway and metal smelt. The direct current measurement is also an important part of electromagnetic measurement. Time research on the large current transformer is meet the requirement of Beijing subway, the maximum current is 12000A and voltage output, it can suit for new type computer relay protection. Firstly, to solve this problem is settle the saturation of the gather magnetic loop (magnetic core). The air gap size and number need to decide; Secondly, the characteristic of Hall chip is deeply studied, the magnetic measurement and the design of electronic circuit of converting it to electric signal; Last, the anti-jamming and error of this CT are theoretically analyzed.