Rogowski sensor and method for measuring a current

• US 7,969,139 B2
• Filed: 12/12/2007
• Issued: 06/28/2011
• Est. Priority Date: 12/21/2006
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Ermisch, Jochen, Volkmar, Ralf-Reiner, Thieme, Frank, Hering, Uwe
• Primary Examiner(s): Nguyen; Ha Tran T
• Assistant Examiner(s): BENITEZ ROSARIO, JOSHUA
• Application Number:
  US12/519,812
• Publication Number:
  US 20100013460A1
• Time in Patent Office: 1,294 Days
• Field of Search: 324/117.R, 324/117.H, 324126-127, 324250-252
• US Class Current: 324/117.00R
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils

Abstract

A Rogowski sensor is provided for measuring a current of an electrical conductor. The sensor has a Rogowski coil, which has an electrical winding resistor, and an integration device which is connected to the Rogowski coil and is intended to generate an output signal which is proportional to the electrical current to be measured by the Rogowski sensor. The integration device is formed by the winding resistor of the Rogowski coil and a capacitance which is connected to the two winding connections of the Rogowski coil, and for the output signal from the integration device to be formed by the voltage applied to the capacitance.

Claims

1. A Rogowski sensor for measuring a current of a conductor, the Rogowski sensor comprising:

a Rogowski coil having an electrical winding resistance and two winding terminations; and

an integration device for generating an output signal that is proportional to the current to be measured by the Rogowski sensor, said integration device being formed by said electrical winding resistance of said Rogowski coil and a capacitance connected to said two winding terminations of said Rogowski coil, said integration device outputting an output signal formed by a voltage present across said capacitance.

2. The Rogowski sensor according to claim 1, wherein said capacitance is formed by a capacitor.

3. The Rogowski sensor according to claim 2, further comprising an electric transmission line, said capacitor is connected indirectly to said two winding terminations of said Rogowski coil via said electric transmission line.

4. The Rogowski sensor according to claim 2, wherein said capacitor is connected directly to said two winding terminations of said Rogowski coil.

5. The Rogowski sensor according to claim 1, wherein said capacitance Ci and said electrical winding resistance Rr are dimensioned in such a way that the following holds:

Rr*Ci>

1/(2*π

*f)

f denoting a frequency of the current to be measured.

6. The Rogowski sensor according to claim 1, wherein said capacitance Ci and said electrical winding resistance Rr are dimensioned such that the following holds:

Rr*Ci>

10/(2*π

*f)

f denoting a frequency of the current to be measured.

7. The Rogowski sensor according to claim 1, wherein said electrical winding resistance lies between 10 kΩ

and 200 kΩ

.

8. The Rogowski sensor according to claim 1, wherein said Rogowski coil has a winding with 1,000 to 10,000 turns.

9. The Rogowski sensor according to claim 8, wherein said winding has a winding wire with a specific resistance of at least 0.05 Ω

mm²/m, and in that a conductor cross section of said winding wire of said winding is 0.005 mm² to 0.05 mm².

10. The Rogowski sensor according to claim 8, wherein said winding has a winding wire with a specific resistance of at least 0.05 Ω

mm²/m.

11. The Rogowski sensor according to claim 8, wherein said winding has a winding wire with a conductor cross section of 0.005 mm² to 0.05 mm².

12. The Rogowski sensor according to claim 1, wherein said capacitance is between 1 μ

F and 100 μ

F.

13. A method for measuring a current of a conductor with an aid of a Rogowski coil having an electrical winding resistance, which comprises the step of:

performing an integration for generating an output signal that is proportional to the current to be measured, the integration being carried out with the aid of the electrical winding resistance of the Rogowski coil and a capacitance connected to two winding terminations of the Rogowski coil; and

outputting a voltage present across the capacitance as the output signal.