Influence of External Currents in Sensors Based on PCB Rogowski Coils

Abstract

Abstract.A current sensor based in the Rogowski coil is an innovative measuring system that gives advantages with respect to conventional measuring systems based in current transformers with magnetic core [1], [2].and [3]. Their main advantages are: the linearity, the span and the bandwidth.Different kinds of manufacturing allow to obtain an important variety of Rogowski coils with different properties. One way of manufacturing is using the same method as for producing printed circuit boards, so by this way is possible to produce coils very similar and with a high precision. The authors are working in current measurement with Rogowski coils or Hall effect sensors and in particular in the realization of good and accurate coils [4] and [5]. In this work, the influence of external currents to the coil in the measured current by the coil has been evaluated.

Effect of the Conductor Positioning on Low-Power Current Transformers: Inputs for the Next IEC 61869-10

“…If the primary conductor position can be "easily" solved with some potential solutions, the returning or external conductor position is not something of straightforward solution (e.g., see [36,40]). The fact is that such conductors may be passing through small areas or substation boxes, where there is no chance of moving them from the LPCT.…”

“…The fact is that such conductors may be passing through small areas or substation boxes, where there is no chance of moving them from the LPCT. The authors in [40] clearly demonstrated that, depending on the external conductor position with respect to the coil, each turn of the LPCT coil is more or less affected by the external cable. From the results, they demonstrate that there could be a magnetic field intensity difference between one turn and another up to seven times.…”

Measurement of Power Frequency Current including Low- and High-Order Harmonics Using a Rogowski Coil

“…Thus, designing a Rogowski coil via new optimization techniques such as particle swarm can be used to achieve the desired performance [31]. Also, a Rogowski coil can be affected by external magnetic fields resulting from external currents [32]. However, this problem can be solved using shielding or two opposite coils designed to reduce this effect [32].…”

Desenvolvimento e instrumentação de um cabeçote de solda a ponto por resistência elétrica para aplicação em condições industriais.

“…O projeto da bobina é muito rápido e permite a instalação em práticamente qualquer pinça de solda. Em contrapartida a essas vantagens estão a baixa quantidade de espiras, e a influencia de campos magnéticos vizinhos a bobina, porém montando duas PCIs com uma em sentido contrario a outra reduz a sensibilidade aos campos e dobra a quantidade de espiras, resolvendo estas desvantagens [Artero, 2005].…”

“…A bobina desenvolvida foi projetada especificamente para instalação em pinças de solda industriais. Como o tamanho deve ser muito pequeno e robusto, construiu-se a bobina em uma placa de circuito impresso (PCI) [Artero, 2005] O integrador pode ser construído analogicamente [Higashi, 2006] ou digitalmente [Zhang Xin, 2010], sendo que o analógico impõe erros no sinal de saída em função da temperatura, offset e ruídos elétricos criados pelo próprio integrador, além de um valor constante e crescente que depende do valor inicial de integração, como descreve a equação de funcionamento de um integrador (3.7) [Higashi, 2006] [ Ward, 1993].…”