System and method for monitoring a DC power system
First Claim
1. A method for performing a capacity test on testing a battery bank comprising at least one battery, the battery bank being part of a load circuit in which the battery bank, a charger, and a system load are arranged in parallel, the battery bank having a nominal capacity and a set of capacity factors, the set of capacity factors including first and second capacity factors Kt1 and Kt2, the method comprising:
- (a) electrically disconnecting the battery bank from the charger and the system load;
(b) placing the battery bank in electrical contact with a capacity test circuit operationally configured to apply a constant resistance across the battery bank;
(c) maintaining the battery bank in electrical contact with the capacity test circuit until the battery bank reaches a predetermined end voltage;
(d) measuring a time to end voltage TD2 comprising a period from the start of step (b) to the end of step (c);
(e) measuring a temperature that is indicative of a temperature of the battery bank and calculating a temperature correction factor Tcf based on the measured temperature;
(f) calculating an average current Iavg consisting of the mean of a first set of measurements of a current flowing through the capacity test circuit, each of the measurements of the first set of measurements being taken at first frequency during the performance of step (c);
(g) calculating an average capacity factor Kt that is equal to the nominal capacity divided by the average current Iavg;
(h) calculating a rated discharge time t for the capacity test performed in steps (a) through (d) as a function comprising a linear interpolation between first and second capacity factors Kt1 and Kt2; and
(i) calculating a percentage C of the nominal capacity as a function of the rated discharge time t, the measured time to end of-voltage TD2, and the temperature correction factor Tcf.
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Accused Products
Abstract
The present application discloses an integrated direct current (DC) subsystem monitoring system for monitoring and reporting status of a utility substation, the DC subsystem monitoring system having the ability to actively monitor and report on changes in the float current and current capacity of the system, as well as to monitor for ground faults.
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Citations
18 Claims
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1. A method for performing a capacity test on testing a battery bank comprising at least one battery, the battery bank being part of a load circuit in which the battery bank, a charger, and a system load are arranged in parallel, the battery bank having a nominal capacity and a set of capacity factors, the set of capacity factors including first and second capacity factors Kt1 and Kt2, the method comprising:
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(a) electrically disconnecting the battery bank from the charger and the system load; (b) placing the battery bank in electrical contact with a capacity test circuit operationally configured to apply a constant resistance across the battery bank; (c) maintaining the battery bank in electrical contact with the capacity test circuit until the battery bank reaches a predetermined end voltage; (d) measuring a time to end voltage TD2 comprising a period from the start of step (b) to the end of step (c); (e) measuring a temperature that is indicative of a temperature of the battery bank and calculating a temperature correction factor Tcf based on the measured temperature; (f) calculating an average current Iavg consisting of the mean of a first set of measurements of a current flowing through the capacity test circuit, each of the measurements of the first set of measurements being taken at first frequency during the performance of step (c); (g) calculating an average capacity factor Kt that is equal to the nominal capacity divided by the average current Iavg; (h) calculating a rated discharge time t for the capacity test performed in steps (a) through (d) as a function comprising a linear interpolation between first and second capacity factors Kt1 and Kt2; and (i) calculating a percentage C of the nominal capacity as a function of the rated discharge time t, the measured time to end of-voltage TD2, and the temperature correction factor Tcf. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for performing a capacity test on a battery bank comprising at least one battery, the battery bank having a nominal capacity, the method comprising:
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(a) connecting the battery bank to a capacity test circuit, the capacity test circuit being configured to apply a constant resistance across the battery bank; (b) measuring a current flow through the capacity test circuit at predetermined intervals from the start of step (a) to when the battery bank reaches a predetermined end voltage, yielding a plurality of current flow measurements; (c) calculating an average current Iavg consisting of a mean of the plurality of current flow measurements; (d) calculating an average capacity factor Kt that is equal to the nominal capacity divided by the average current Iavg; and (e) calculating a percentage C of the nominal capacity based on the average capacity factor Kt. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification