Study On The Electronic Current Transducer (ECT)

As important equipment of relay protection and electric energy measure in power system industry, current transducers play a primary role for working well and calculating precisely in power supplying system. Economical and secure operation of power system is closely related with precision and dependability of current transducers. With the development of national economy, the new grade of voltage of power supply is improving constantly, the systematic measurement and precision of protection demand to be improving constantly, the traditional electromagnetic current transducers expose the shortcoming that can't be overcome, the electronic current transducers is the new-type optical and electronic current transducers which incorporate electronic technology and optical technology into an organic whole, its characteristics, such as high accuracy , high dependability , wide bandwidth ,etc. have already become the substitute of the traditional electromagnetic current transducer in power industry gradually.This text directs against the requisition for the electronic current transducers of power industry, According to the national relevant standard, we design a new type of electronic current transducer. Adopting Rogowski coil as sensor on the high-voltage line, after digitizing the output of Rogowski coil, we convey it to the low-voltage part by digital transmission system, and resume it into original analog signal in" order to realize the measurement of the current of the high-voltage bus. System adopts the way of low-voltage part controlling high-voltage part to realize the synchronization of the two parts. We make use of digital transmission system to realize totally isolate and signal transmission between the high-voltage part and low-voltage part. This method has improved the anti-interference of signal transmission, With the use of the computer interface technology to read the sampling data, we carry on corresponding adjustment to the data-sampling system according to the result of data processing .The electronic current transducer we designed has digital and analogy two dating output ways, which provides good connect with other automation equipments.The experiment proves that the electronic current transducers designed is simple and practical, which have good linear degree and measure precision, and can measure current in the wide range, These current transducers have many virtues, such as response speedily, wide bandwidth etc. Comparing with the traditional electromagnetic current transducers, questions such as being flammable and explosive caused by oil , the magnetism saturation and insulation between the high-voltage and low-voltage, that the electronic current transducer designed has been overcame Because of the low cost, wide bandwidth. Simple and practicality, the electronic current transducers have greater application prospects.