Branch Circuit Monitor

Abstract

A branch circuit monitoring system (BCMS) for monitoring branch circuit currents in one or more electrical circuit panels is described. The system is comprised of a data center server, one or more panel processors, each with one or more collection devices, and one or more current sensors per collection device. The BCMS is designed to be installed entirely inside the panel without the need for a dedicated enclosure or power supply to facilitate ease of installation and low-cost. The BCMS also allows for future upgradability through standard software updates so that the system can be updated or patched easily. The BCMS data center server collects, aggregates, stores, and serves historical branch circuit current data from the panel processors to networked users via a web server to provide visualization of data such as tables, charts, and gauges. Finally, the BCMS interfaces to third-party software suites using industry-standard protocols such as Modbus® TCP and BACnet™ for integration with data center infrastructure management or building management system software.

What is claimed is: 
     
         1 . A branch circuit monitoring system, comprising:
 a first collection device configured to receive direct current (DC) signals indicative of a measured DC current value from a first plurality of current monitors and multiplex the DC signals from the first plurality of current monitors;   a second collection device configured to receive DC signals indicative of a measured DC current value from a second plurality of current monitors and multiplex the DC signals from the second plurality of current monitors;   a panel processor device in communication with the first and second collection devices configured to receive the DC signals from each of the first and second current monitors, the panel processor device configured to store in a local memory a plurality of data structures comprising the measured DC current data values.   
     
     
         2 . The branch circuit monitoring system of  claim 1  further comprising a first plurality of current monitors, each of the first plurality of current monitors comprising non-contact current sensors configured to produce a DC voltage proportional to a DC current flowing through one of a first plurality of branch circuit conductors. 
     
     
         3 . The branch circuit monitoring system of  claim 2  wherein the non-contact current sensors of the first plurality of current monitors comprises at least one Hall Effect sensor. 
     
     
         4 . The branch circuit monitoring system of  claim 2  further comprising a second plurality of current monitors, each of the second plurality of current monitors comprising non-contact current sensors configured to produce a DC voltage proportional to a DC current flowing through one of a second plurality of branch circuit conductors. 
     
     
         5 . The branch circuit monitoring system of  claim 4  wherein the non-contact current sensors of the first plurality of current monitors and the second plurality of current monitors each comprises at least one Hall Effect sensor. 
     
     
         6 . The branch circuit monitoring system of  claim 2  wherein at least two of the first plurality of current monitors are each coupled with a sub-branch of a first branch circuit of the first plurality of branch circuits and configured to measure a current value within the sub-branches of the first branch circuit of the first plurality of branch circuits. 
     
     
         7 . The branch circuit monitoring system of  claim 6  wherein a measured current value of the first branch circuit is determined by summing the measured current values of each of the sub-branches. 
     
     
         8 . The branch circuit monitoring system of  claim 1  wherein the panel processor polls the first and second collection devices for the first and second DC signals. 
     
     
         9 . The branch circuit monitoring system of  claim 1  wherein the data structure comprises a branch identifier, a measured current and a time stamp. 
     
     
         10 . The branch circuit monitoring system of  claim 1  wherein the panel processor is configured to provide the data structure over a data connection to a building management system. 
     
     
         11 . The branch monitoring system of  claim 1  further comprising a building management system running on a server machine, the building management system including a branch circuit monitoring module configured to receive the branch circuit monitoring data over a data connection, the branch circuit monitoring module further configured to display the branch circuit monitoring data within the building management system. 
     
     
         12 . The branch monitoring system of  claim 1  wherein the signal indicative of the measured current comprises a voltage level. 
     
     
         13 . The branch monitoring system of  claim 1  wherein the signal indicative of the measured current comprises a digital value. 
     
     
         14 . The branch circuit monitoring system of  claim 1  wherein the panel processor device comprises a network interface and is configured to communicate with a server to provide the stored plurality of data structures via the network interface. 
     
     
         15 . The branch circuit monitoring system of  claim 14  further comprising a server and an associated database configured to receive data structures from the panel processors over a network via the network interface of the panel processor device. 
     
     
         16 . The branch circuit monitoring system of  claim 1  wherein the first collection device is further configured to receive direct current (DC) signals indicative of a measured DC voltage value from a first plurality of voltage monitors. 
     
     
         17 . The branch circuit monitoring system of  claim 16  wherein the second collection device is further configured to receive direct current (DC) signals indicative of a measured DC voltage value from a second plurality of voltage monitors. 
     
     
         18 . The branch circuit monitoring system of  claim 1  wherein the panel processor is configured for self-discovery of a new collection device. 
     
     
         19 . A method of branch circuit monitoring, comprising:
 receiving, at a first collection device, a first plurality of signals indicative of a first plurality of measured current values of a first plurality of branch circuits;   multiplexing, at the first collection device, the first plurality of signals indicative of the first plurality of measured current values;   receiving, at a second collection device, a second plurality of signals indicative of a second plurality of measured current values of a second plurality of branch circuits;   multiplexing, at the second collection device, the second plurality of signals indicative of the second plurality of measured current values;   receiving, at a panel processor in communication with the first and second collection devices, the first and second plurality of DC signals; and   storing, in a local memory of the panel processor, a plurality of data structures comprising the measured branch circuit current data values for said branch circuit along with a timestamp associated with a time at which the currents were measured.   
     
     
         20 . The method of  claim 19  further comprising measuring a first plurality of currents within a first plurality of branch circuits using a first plurality of current monitors each coupled with a respective branch of the first plurality of branch circuits. 
     
     
         21 . The method of  claim 20  wherein the operation of measuring a first plurality of currents is performed at least in part via at least one Hall Effect sensor. 
     
     
         22 . The method of  claim 20  further comprising measuring a second plurality of currents within a second plurality of branch circuits using a second plurality of current monitors each coupled with a respective branch of the second plurality of branch circuits. 
     
     
         23 . The method of  claim 22  wherein the operation of measuring a second plurality of currents is performed at least in part via at least one Hall Effect sensor. 
     
     
         24 . A method of calibrating the branch circuit monitoring system of  claim 1 , comprising:
 a calibration apparatus configured to deliver a known current through a conductor; and   a calibration algorithm and software to solve an equation representing the current sensor response to a current through a conductor.