Method and power distribution unit for limiting a total delivered power

1. A method of limiting a total power delivered by a power distribution unit (PDU) servicing a plurality of circuits, each circuit having a corresponding output connector, the method comprising:

assigning a power threshold for each of the plurality of output connectors;

sensing a power level of a given one of the plurality of output connectors;

detecting when the power level of the given one of the plurality of output connectors exceeds a fixed power limit and generating a corresponding fault signal; and

stopping a delivery of power to the given one of the plurality of output connectors, based on a corresponding fault signal, when the power level of the given one of the plurality of output connectors exceeds the assigned power threshold for the given one of the plurality of output connectors;

wherein the power thresholds for each of the plurality of output connectors are assigned so that a sum of the power thresholds assigned to the plurality of output connectors does not exceed a maximum rated power for the PDU, the maximum rated power of the PDU being less than a sum of power limits of the plurality of output connectors.

2. The method of claim 1 , wherein sensing the power level of the given one of the plurality of output connectors comprises:

sensing a power parameter selected from a voltage, a current, an effective current, an instantaneous power, an instantaneous active power, an instantaneous reactive power, a phase angle of the voltage relative to the current, and a combination thereof; and

calculating the power level of the given one of the plurality of output connectors based on the sensed power parameter.

3. The method of claim 1 , further comprising providing a first visual indication in proximity to the given one of the plurality of output connectors when stopping the delivery of power to the given one of the plurality of output connectors.

4. The method of claim 1 , further comprising providing a second visual indication in proximity to one of the plurality of output connectors having an assigned power threshold of zero.

5. The method of claim 1 , wherein different power thresholds are assigned to at least a subset of the plurality of output connectors.

6. The method of claim 1 , wherein assigning the power threshold for each of the plurality of output connectors comprises assigning a current limit for each of the plurality of output connectors.

7. The method of claim 1 , further comprising transmitting from the PDU, over a power line, an indication of the power level of the given one of the plurality of output connectors.

8. The method of claim 7 , wherein the indication of the power level of the given one of the plurality of output connectors is transmitted over the power line using a power line communication (PLC) protocol.

9. The method of claim 1 , further comprising:

receiving a user command to rearm the given one of the plurality of output connectors; and

resuming the delivery of power to the given one of the plurality of output connectors in response to the user command.

10. A power distribution unit (PDU), comprising:

an input connector;

a plurality of output connectors;

a plurality of circuits, each circuit being adapted to selectively connect the input connector to a corresponding one of the plurality of output connectors, each circuit comprising a sensor adapted to sense a power level of the corresponding one of the plurality of output connectors and a detector, operatively coupled to the sensor, configured to detect when a respective power level exceeds a fixed power limit and to generate a fault signal; and

a controller operatively connected to the plurality of circuits, the controller being adapted to:

assign a power threshold to each of the plurality of output connectors,

cause a disconnection of a given one of the plurality of output connectors from the input connector, based on a fault signal of the detector corresponding to one of the plurality of circuits when the power level of the given one of the plurality of output connectors exceeds the assigned power threshold for the given one of the plurality of output connectors, and

assign the power thresholds to each of the plurality of output connectors so that a sum of the power thresholds assigned to the plurality of output connectors does not exceed a maximum rated power for the PDU, the maximum rated power of the PDU being less than a sum of power limits of the plurality of output connectors.

11. The PDU of claim 10 , wherein:

the sensor of each of the plurality of circuits is selected from a voltmeter, an ammeter, a power meter and a combination thereof; and

the controller is further adapted to calculate a power level of each of the output connectors based on a power parameter provided by the sensor.

12. The PDU of claim 10 , wherein each of the plurality of circuits comprises a relay, the controller causing the relay of the corresponding one of the plurality of circuits to disconnect the given one of the plurality of output connectors from the input connector.

13. The PDU of claim 10 , wherein the detector of each of the plurality of circuits enforces a same fixed power limit greater than any one of the assigned power thresholds.

14. The PDU of claim 10 , further comprising a power line communication (PLC) protocol modem operatively connected to the controller and adapted to transmit an indication of the power level of at least one of the output connectors over a power line connected to the input connector.

15. The PDU of claim 10 , further comprising a user interface operatively connected to the controller, wherein the controller is further adapted to:

receive a user command from the user interface; and

cause the plurality of circuits to reconnect the given one of the plurality of output connectors to the input connector when receiving the user command from the user interface.