Grid shield

1 . A grid-shielded electrical system for a transportation refrigeration system, the grid-shielded electrical system comprising:

a bus to deliver three-phase grid power, which is received from a grid, to electrical components of the transportation refrigeration system;

a voltage sensor disposed to sense a condition of voltage on the bus and configured to generate voltage readings accordingly; and

a controller disposed in signal communication with the voltage sensor and configured to detect a root cause issue with the grid based on the voltage readings,

wherein:

the grid-shielded electrical system further comprises a current sensor disposed to sense a condition of current on the bus and configured to generate current readings accordingly, and

the controller is disposed in signal communication with the current sensor and configured to detect, in an absence of the root cause issue, a non-grid issue based on the current readings.

2 . The grid-shielded electrical system according to claim 1 , wherein:

the bus comprises a three-phase bus,

the voltage sensor senses the condition of voltage on each phase of the three-phase bus, and

the controller is configured to detect the root cause issue from at least one of an unbalanced phase and a phase loss for a predefined time for each phase of the three-phase bus based on the voltage readings.

3 . The grid-shielded electrical system according to claim 1 , wherein the controller is further configured to shut down the electrical components when the root cause issue is detected and to automatically restart the electrical components once the root cause issue is no longer detected.

4 . The grid-shielded electrical system according to claim 1 , wherein:

the bus comprises a three-phase bus,

the current sensor senses the condition of current on each phase of the three-phase bus, and

the controller is configured to detect, in the absence of the root cause issue, the non-grid issue from at least one of a low amperage condition and a sustained high amperage condition for each phase of the three-phase bus based on the current readings.

5 . The grid-shielded electrical system according to claim 1 , wherein the controller is further configured to continue operations of the electrical components in the absence of the root cause issue and in an absence of the non-root cause issue.

6 . The grid-shielded electrical system according to claim 1 , wherein the bus comprises a three-phase bus, the voltage sensor disposed to sense a condition of voltage on each phase of the three-phase bus.

7 . A transportation refrigeration unit for a shipping container, the shipping container configured to be transported by a ship, the transportation refrigeration unit comprising:

a grid-shielded electrical system, the grid-shielded electrical system comprising:

a bus to deliver three-phase grid power, which is received from a grid of the ship, to electrical components of the transportation refrigeration system;

a voltage sensor disposed to sense a condition of voltage delivered to the bus and configured to generate voltage readings accordingly; and

a controller disposed in signal communication with the voltage sensor and configured to detect a root cause issue with the grid based on the voltage readings,

wherein the transportation refrigeration unit is operable in a standby mode while on board the transport ship and connected to the grid, the grid exclusively powering the electrical components in the stand-by mode, and

wherein:

the grid-shielded electrical system further comprises a current sensor disposed to sense a condition of current on the bus and configured to generate current readings accordingly from at least one of a low amperage condition and a sustained high amperage condition for each phase of the three-phase bus based on the current readings, and

the controller is disposed in signal communication with the current sensor and configured to detect, in an absence of the root cause issue, a non-grid issue based on the current readings from the at least one of the low amperage condition and the sustained high amperage condition for each phase of the three-phase bus based on the current readings.

8 . The transportation refrigeration unit according to claim 7 , wherein the voltage sensor is configured across multiple grid-shielded electrical systems of multiple transportation refrigeration units, each respectively comprising an independent bus and an independent controller, the voltage sensor disposed to sense a condition of voltage on each bus and configured to generate voltage readings accordingly.

9 . The transportation refrigeration unit according to claim 7 , wherein the voltage sensor is disposed on the bus of the transportation refrigeration unit.

10 . The transportation refrigeration unit according to claim 7 , wherein the voltage sensor is disposed between the bus of the transportation refrigeration unit and the grid.

11 . A grid-shielded electrical system for a transportation refrigeration system, the grid-shielded electrical system comprising:

a current sensor disposed to sense a condition of current on a bus configured to deliver a three-phase grid power, wherein the current sensor is further configured to generate current readings; and

a controller disposed in signal communication with the current sensor,

the controller being configured to detect, in an absence of a root cause issue, a non-grid issue based on the current readings.

12 . A method of operating a transportation refrigeration system comprising the grid-shielded electrical system according to claim 11 , the method comprising:

delivering the three-phase grid power, which is received from a grid, to electrical components of the transportation refrigeration system via the three-phase bus;

sensing, with a voltage sensor, a condition of voltage on each phase of the three-phase bus and generating voltage readings accordingly; and

detecting, with the controller, the root cause issue with the grid based on the voltage readings.

13 . The method according to claim 12 , wherein the detecting of the root cause issue comprises detecting the root cause issue from at least one of an unbalanced phase and a phase loss for a predefined time for each phase of the three-phase bus based on the voltage readings.

14 . The method according to claim 12 , wherein the detecting of the non-grid issue comprises detecting, in the absence of the root cause issue, the non-grid issue from at least one of a low amperage condition and a sustained high amperage condition for each phase of the three-phase bus based on the current readings.

15 . The method according to claim 12 , further comprising:

shutting down the electrical components when the root cause issue is detected;

automatically restarting the electrical components once the root cause issue is no longer detected; and

continuing operations of the electrical components in the absence of the root cause issue and in an absence of the non-root cause issue.

16 . The grid-shielded electrical system according to claim 11 , wherein the bus is configured to deliver the three-phase grid power from a grid to electrical components of the transportation refrigeration system.

17 . The grid-shielded electrical system according to claim 11 , wherein the grid-shielded electrical system further comprises a voltage sensor disposed to sense a condition of voltage on the bus and configured to generate voltage readings accordingly.

18 . The grid-shielded electrical system according to claim 11 , wherein the controller is further disposed in signal communication with a voltage sensor and configured to detect the root cause issue with the grid based on the voltage readings.