Intelligent Electronic Device Having Circuitry for Reducing the Burden on Current Transformers
First Claim
1. A current sensor comprising:
- a transformer including a primary winding configured for sensing a current delivered to a load and a secondary winding configured for outputting a scaled current; and
an amplification circuit configured for variably amplifying the scaled output current and maintaining the output of the secondary winding at near zero voltage.
2 Assignments
0 Petitions
Accused Products
Abstract
An intelligent electronic device (IED), e.g., an electrical power meter, having circuitry for reducing the burden placed on at least one current sensor of the device resulting in a highly accurate measurement by the at least one current sensor is provided. The circuitry of the present disclosure reduces the burden on the current sensor while providing amplification, e.g., gain control, to the input signal. The circuitry includes at least one current sensor outputting a signal to an operational amplifier (op amp) having a controlled variable feedback resistance. By employing an operational amplifier in the circuitry, the output of the current sensor will be at a near zero volts condition at all times thus reducing the burden on the current sensor.
51 Citations
15 Claims
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1. A current sensor comprising:
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a transformer including a primary winding configured for sensing a current delivered to a load and a secondary winding configured for outputting a scaled current; and an amplification circuit configured for variably amplifying the scaled output current and maintaining the output of the secondary winding at near zero voltage. - View Dependent Claims (2, 3, 4, 5)
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6. A current sensor comprising:
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a transformer including a primary winding configured for sensing a current delivered to a load and a secondary winding configured for outputting a scaled current; an operational amplifier coupled across the output of the secondary winding and configured for maintaining the output of the secondary winding at near zero voltage condition; and a variable feedback resistance coupled to the input of the operational amplifier configured for variably amplifying the scaled output current. - View Dependent Claims (7, 8)
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9. An intelligent electronic device comprising:
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a transformer including a primary winding configured for sensing a current delivered to a load and a secondary winding configured for outputting a scaled current; an amplification circuit configured for variably amplifying the scaled output current and maintaining the output of the secondary winding at near zero voltage; at least one analog-to-digital converter configured for receiving the amplified output and converting the amplifier output to a digital signal; and a processor configured to receive the digital signal and determine a value for the current delivered to the load. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification