On shunt-based sensing technologies for current input channels of protection and control IED's

Emerging applications in substation automation like travelling waves for fault location requires current channel inputs of the intelligent electronic devices (IED) with very large dynamic range and extended bandwidth. These new requirements cannot be fulfilled by traditional architectures based on current transformers; thus they call for innovative solutions. This paper presents the resistive shunt-based technology and compare it to conventional transformers. The high linearity of shunts, their low parasitic inductance and capacitance, in conjunction with high accuracy and large bandwidth of an isolated sigma-delta modulator for analog to digital conversion, provide unmatched performances of the overall acquisition chain. Test results of the Hitachi Energy SAM600 3.0 process interface unit (PIU) using shunt technology prove the fulfilment of high accuracy classes of IEC 61869-13, both for measurement and protection.