System and method for detecting the presence of an unsafe line condition in a disconnected power meter
First Claim
1. A method for detecting the presence of an unsafe condition at a power metering device, said power metering device interposed between a voltage source and a load said power metering device connecting to said load at a first load contact and a second load contact, said power metering device having a disconnect switch, said disconnect switch having an open position, said disconnect switch disabling power from flowing through said power metering device from the voltage source to the load when the disconnect switch is in the open position, the method comprising:
- determining if the disconnect switch is in the open position,measuring a first voltage at said first load contact;
measuring a second voltage at said second load contact;
determining if the first voltage is greater than a first voltage threshold or less than a second voltage threshold;
determining if the second voltage is greater than a first voltage threshold or less than a second voltage threshold;
indicating that an unsafe condition exists if either;
a) the first voltage is greater than the first voltage threshold;
or,b) the second voltage is less than the second voltage threshold;
or,c) the second voltage is greater than the first voltage threshold;
ord) the first voltage is less than the second voltage threshold; and
,the disconnect switch is in the open position.
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Accused Products
Abstract
A method of detecting the presence of an unsafe line condition at a power metering device is disclosed. The method comprises the steps of determining if a disconnect switch is in the open position, and measuring a first voltage at a first load contact. The method measures a second voltage at a second load contact and determines if the first voltage is greater than a first voltage threshold or less than a second voltage threshold. The method further determines if the second voltage is greater than the first voltage threshold or less than the second voltage threshold. The method indicates that an unsafe condition exists if either the first voltage is greater than the first voltage threshold, or first voltage is less than the second voltage threshold or the second voltage is greater than the first voltage threshold or the second voltage is less than the second voltage threshold, when the disconnect switch is in the open position.
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Citations
23 Claims
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1. A method for detecting the presence of an unsafe condition at a power metering device, said power metering device interposed between a voltage source and a load said power metering device connecting to said load at a first load contact and a second load contact, said power metering device having a disconnect switch, said disconnect switch having an open position, said disconnect switch disabling power from flowing through said power metering device from the voltage source to the load when the disconnect switch is in the open position, the method comprising:
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determining if the disconnect switch is in the open position, measuring a first voltage at said first load contact; measuring a second voltage at said second load contact; determining if the first voltage is greater than a first voltage threshold or less than a second voltage threshold; determining if the second voltage is greater than a first voltage threshold or less than a second voltage threshold; indicating that an unsafe condition exists if either; a) the first voltage is greater than the first voltage threshold;
or,b) the second voltage is less than the second voltage threshold;
or,c) the second voltage is greater than the first voltage threshold;
ord) the first voltage is less than the second voltage threshold; and
,the disconnect switch is in the open position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for detecting the presence of an unsafe condition at a power metering device, said power metering device interposed between a voltage source and a load said power metering device connecting to said load at a first load contact and a second load contact, said power metering device having a disconnect switch, said disconnect switch operable between a closed position and an open position, the method comprising:
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determining if the disconnect switch is in the closed position, operating the disconnect switch to the open position if the disconnect switch is in the closed position, measuring a first voltage at the first load contact; measuring a second voltage at the second load contact; determining if the first voltage is greater than a first voltage threshold or less than a second voltage threshold; determining if the second voltage is greater than a first voltage threshold or less than a second voltage threshold; indicating that an unsafe condition exists if either; a) the first voltage is greater than the first voltage threshold;
or,b) the second voltage is less than the second voltage threshold;
or,c) the second voltage is greater than the first voltage threshold;
or,d) the first voltage is less than the second voltage threshold. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. An apparatus for detecting the presence of an unsafe condition at a power metering device, the power metering device interposed between a voltage source and a load, the power metering device measuring power flowing from the voltage source to the load, the apparatus comprising:
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a disconnect switch, the disconnect switch interposed between the load and the voltage source, the disconnect switch interrupting the flow of power from the voltage source to the load when the disconnect switch is in an open position; a load side voltage sensing circuit, the load side voltage sensing circuit coupled to the load at a first load contact and a second load contact, the load side voltage sensing circuit measuring a first voltage at the first load contact and measuring a second voltage at the second load contact, the load side voltage sensing circuit determining; a) if the first voltage is greater than a first voltage threshold or b) if the first voltage is less than a second voltage threshold, or c) if the second voltage is greater than a first voltage threshold;
or,d) if the first voltage is less than a second voltage threshold; and
,a processing circuit coupled to the disconnect switch and the load side voltage sensing circuit, the processing circuit determining if the disconnect switch is in the open position, the processing circuit indicating that an unsafe condition exists when either the first voltage is greater than the first voltage threshold or, the first voltage is less than the second voltage threshold, or the second voltage is greater than the first voltage threshold or the second voltage is less than the second voltage threshold, and the disconnect switch is in the open position. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification