Traceable calibration system for non-conventional current sensors with analogue or digital output

Reference system for current sensor calibrations at power frequency and for wideband frequencies

“…Generally, the calibration system for power frequency and wideband frequencies is mainly composed of a current 19NRM05 -IT4PQ and 19ENG08 -WindEFCY 978-1-6654-1639-9/22/$31.00 ©2022 IEEE generation system [10] (marked as red block), a set of reference CTs with associated precision resistors (marked as green blocks in the path N), the DUT (DUT I and DUT II, marked as yellow blocks in the path X) and a high precision 2-channel measuring system (MS, marked as grey block). Specifically, the calibration setups are introduced in Subsection II-A about calibrations at power frequency, Subsection II-B about calibrations for wideband frequencies and Subsection II-C about additional design for the voltage amplifier of the Rogowski coils.…”

“…The C-to-V transformers [10] with rated primary currents ranging from 8.3 A to 1500 A were developed as a reference set for wideband calibrations up to 12 kHz. The reference Cto-V transformer is made up of a symmetrical CT and associated precise measuring resistors.…”

How Instrument Transformers Influence Power Quality Measurements: A Proposal of Accuracy Verification Tests

“…The international technical standards [ 2 , 3 , 15 , 16 , 17 ] on PQ describe the characteristics of voltage waveforms at a given point of low voltage (LV), medium voltage (MV) and high voltage (HV) public power networks, with the assessing methods for PQ phenomena. The scientific literature [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ] is mainly focused on measurement campaigns with a statistical approach, using the standard assessment methods. In the following, a list of the considered PQ disturbances is provided.…”

“…The setups of a reference system for current sensor calibrations at power frequency up to 5 kA and for the wideband frequencies up to 9 kHz are illustrated in Figure 2 (more details in [ 18 ]). The calibration system is mainly made up of a current generation system [ 19 ] (marked as a red block), a set of reference current-to-voltage (C-to-V) transformers (marked as green blocks in the path N), the device under test (DUT, marked as yellow blocks in the path X) and a high precision two-channel measuring system (MS, marked as a grey block). The DUT shown as a general C-to-V transformer in Figure 2 represents any type of current sensors under test such as an inductive current transformer under test with a reference measuring resistor connected to the secondary, a Rogowski coil with or without active integrator or a high-current shunt.…”

“…The restriction at frequencies greater than 500 Hz for 1 kA is due to the inherent stray inductance of the high current generating transformer. The reference C-to-V transformer with rated primary currents ranging from 8.3 A to 1500 A for wideband calibrations up to 12 kHz is composed of a symmetrical CT and associated precise measuring resistor (more details in [ 19 ]). The accuracies of the reference CTs are within 10 µA/A and 1 μrad at power frequency.…”