Protection architecture for an electrical panel
An electronic protection system is implemented in an electrical panel that distributes electricity to branch circuits at a site. The electronic protection system includes a current sensor, an actuator and a processor. The current sensor senses a current flow through a branch circuit. The actuator is used to de-energize the branch circuit. The processor controls the actuator based on the current flow sensed by the current sensor, according to a trip-time curve implemented by the processor. The trip-time curve specifies a maximum duration of current flow for different amounts of current flow.
1 . An electronic protection system implemented in an electrical panel for a site, wherein the electrical panel distributes electricity from a source to branch circuits at the site, the electronic protection system comprising:
a current sensor configured to sense a current flow through a branch circuit;
an actuator configured to de-energize the branch circuit; and
a processor that controls the actuator based on the current flow sensed by the current sensor and according to a trip-time curve implemented by the processor, wherein the trip-time curve specifies a maximum duration of current flow through the branch circuit for different amounts of current flow through the branch circuit;
wherein the current sensor, actuator and processor are all implemented in the electrical panel.
2 . The electronic protection system of claim 1 wherein the trip-time curve specifies different maximum durations for current flows in opposite directions through the branch circuit.
3 . The electronic protection system of claim 1 wherein the trip-time curve disallows current flow into the electrical panel from the branch circuit.
4 . The electronic protection system of claim 1 wherein the processor dynamically changes the trip-time curve based on conditions at the site.
5 . The electronic protection system of claim 1 wherein the trip-time curve is updateable by download over the Internet.
6 . The electronic protection system of claim 1 wherein the electrical panel is operated either in a grid-connected mode or in an islanded mode, and the processor changes the trip-time curve based on the mode.
7 . The electronic protection system of claim 1 further comprising:
a circuit breaker in series with the actuator, wherein the circuit breaker de-energizes the branch circuit upon a current overload.
8 . The electronic protection system of claim 1 wherein the processor also provides a warning according to a second trip-time curve implemented by the processor.
9 . The electronic protection system of claim 1 wherein the trip-time curve provides protection against damage for equipment on the branch circuit.
10 . The electronic protection system of claim 1 wherein the trip-time curve is software-defined.
11 . The electronic protection system of claim 4 wherein the processor derates the trip-time curve based on electrical power available to the electrical panel.
12 . The electronic protection system of claim 4 wherein the processor dynamically changes the trip-time curve based on a load on the branch circuit.
13 . The electronic protection system of claim 4 wherein the processor selects the trip-time curve from a set of trip-time curves for different conditions at the site.
14 . The electronic protection system of claim 7 wherein the trip-time curve specifies a protection below the current overload of the circuit breaker.
15 . An electronic protection system implemented in an electrical panel that distributes electricity to branch circuits at a site, the electronic protection system comprising:
multiple current sensors configured to sense current flow through different branch circuits;
multiple actuators configured to de-energize the branch circuits; and
a processor that controls the actuators based on the current flows sensed by the current sensors according to trip-time curves implemented by the processor, wherein at least two of the branch circuits are controlled by different trip-time curves, and each trip-time curve specifies a maximum duration of current flow for different amounts of current flow.
16 . The electronic protection system of claim 15 wherein at least one of the trip-time curves specify different maximum durations for current flows in opposite directions through the branch circuit.
17 . The electronic protection system of claim 15 wherein the processor dynamically changes at least one of the trip-time curves based on conditions at the site.
18 . The electronic protection system of claim 15 further comprising:
a circuit breaker in series with at least one of the actuators, wherein the circuit breaker de-energizes the branch circuit upon a current overload, and the trip-time curve for that branch circuit specifies a protection below the current overload of the circuit breaker.
19 . The electronic protection system of claim 17 wherein the processor dynamically changes the at least one trip-time curve based on a load on one of the branch circuits.
20 . The electronic protection system of claim 17 wherein the processor selects the at least one trip-time curve from a set of trip-time curves for different conditions at the site.