Current transformer and rogowski coil
Current transformer is an important equipment used for current sampling and relay protection in power system. It is an important parameter source of power system and guarantee of safe, reliable and economic operation [1]. In addition, with the intelligent development of various kinds of high and low voltage electrical systems, electrical appliances themselves have put forward higher requirements for the accuracy of current detection. Although the traditional electromagnetic sampling current transformer has high accuracy, it is difficult to meet the requirements of the current power grid development due to problems such as magnetic core saturation, small range under high precision, magnetic core nonlinearity, large weight and volume .
However, the sampling current transformer with rogowski coil as detecting element does not have the problem of magnetic core saturation and magnetic core nonlinearity. Its current measurement range is large, linearity is good, size is small, weight is light, simple structure is easy to process, simple insulation, but compared with the traditional electromagnetic current transformer, high precision is its only weakness, and it has harsh requirements on the working environment, easy to be affected by external electromagnetic interference, especially in the electrical equipment with very compact space, the electromagnetic environment is complex, and limited by space. It is also difficult to use good electromagnetic shielding.
