SELF-POWERED MEASURING APPARATUS AND MEASUREMENT METHOD

• US 20180299492A1
• Filed: 07/07/2016
• Published: 10/18/2018
• Est. Priority Date: 08/19/2015
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Maier, Martin, Weiss, Uwe
• Granted Patent: US 10,514,397 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 15/04 Voltage dividers
• CPC Class Codes: G01R 15/08 Circuits for altering the measuring range
• CPC Class Codes: G01R 15/18 using inductive devices, e.g. transformers
• CPC Class Codes: G01R 19/257 using analogue/digital converters of the type with comparison of different reference values with the value of voltage or current, e.g. using step-by-step method

Abstract

The present embodiments relate to a measuring apparatus and an associated measurement method. The measuring apparatus is installed on a line and includes a sensing unit having a first and a second voltage divider for producing a first and a second measurement signal with a measurement transducer. The first and second measurement signals are each forwardable via a measurement line directly to a signal transducer. The signal transducer is supplied with power via a supply line by being switchably connected to the measurement transducer.

Claims

1. A measuring device for determining a current intensity on a line, the measuring device comprising:

a determining unit having a first and a second voltage divider for generating a first and a second measurement signal with a measuring transformer,

wherein the first and the second measurement signal are configured to be passed directly, over a measurement line, to a signal converter,

wherein, for supplying current to the signal converter, the signal converter is switchably connected to the measuring transformer by way of a supply line.

2. The measuring device of claim 1, wherein the signal converter is configured as an analog-to-digital converter.

3. The measuring device of claim 1, wherein a switch element for actuating the switchable power supply to the signal converter is connected to a switch element for providing a reference voltage by way of an adjustable coupling.

4. The measuring device of claim 3, wherein at least one of the switch elements is configured to be actuated by a clock generator.

5. The measuring device of claim 3, wherein, with the coupling, the duration of a delay between a switch signal of the clock generator and the actuation of the switch element of the supply line is adjustable.

6. The measuring device of claim 1, wherein the first voltage divider is configured for determining a first value range of the current intensity on the line, and the second voltage divider is configured for determining a second value range of the current intensity on the line.

7. The measuring device of claim 1, wherein the determining unit also includes at least one third voltage divider for generating a third measurement signal.

8. The measuring device of claim 1, wherein at least one of the voltage dividers includes two resistors connected in series.

16. The measuring device of claim 1, wherein the signal converter is immediately and directly switchably connected to the measuring transformer.

17. The measuring device of claim 5, wherein the duration of the delay is adjustable to a value between 0 ms and 20 ms.

9. A method for measuring a current intensity on a line, the method comprising:

generating a primary measurement signal using a measuring transformer;

processing the primary measurement signal by a first and a second voltage divider to generate a first and a second measurement signal; and

determining and evaluating the first measurement signal, the second measurement signal, or the first and the second measurement signals to generate a measured value using a signal converter,

wherein power is switchably supplied to the signal converter through the measuring transformer.

10. The method of claim 9, wherein the signal converter is an analog-to-digital converter.

11. The method of claim 9, wherein a switch element in a supply line to the signal converter is opened and closed by a clock generator having an adjustable clock signal.

12. The method of claim 11, wherein the switch signal is output substantially at the same time as actuation of a switch element configured to supply at least one of the voltage dividers with a reference voltage.

13. The method of claim 11, wherein the higher the current intensity on the line, the shorter the duration of inactive phases between active phases of the power supply to the signal converter.

14. The method of claim 13, wherein, within an operating interval, the ratio of the duration of inactive phases to the duration of active phases is between zero and ten.

15. The method of claim 9, wherein during determining and evaluating the first measurement signal, the second measurement signal, or the first and the second measurement signals, only the first measurement signal is evaluated if the current intensity is below a first threshold value, and the first and the second measurement signals are evaluated if the current intensity is between the first and a second threshold value, and only the second measurement signal is evaluated if the current intensity is above the second threshold value.