Modular interconnection device and system thereof

Abstract

Embodiments of the present disclosure relate to a modular interconnection device (MID) and a power grid system. The MID includes a modular port assembly, a node, a converter, and a local controller. The modular port assembly is configured to deliver alternating current and / or direct current. The node is coupled to an AC source via a first switch and the modular port assembly. The first switch is configured to selectively disconnect the modular interconnection device from the AC source. The converter is coupled to the node via a second switch and to a DC source via a third switch. The converter is configured to convert AC current to DC current or DC current to AC current. The local controller is coupled to the first switch, the second switch, and the third switch and is configured to control operation of the first switch, the second switch, and the third switch.

Description

TECHNICAL FIELD

[0001] Example embodiments of the present disclosure generally relate to power devices and systems, and more particularly to modular interconnection devices and systems. BACKGROUND

[0002] A power grid generally consists of various power sources and transmission lines, and electricity is delivered through the power grid and consumed by loads connected to the power grid.

[0003] A global control center of the power grid monitors the operation of the power grid or receives information of the status of the power grid, so that the control center can control the distribution of electricity on the power grid. For example, the global control center can control the power grid to direct electricity to places where electricity is in short supply.

[0004] Feeder lines, which typically include alternating current (AC) or direct current (DC) power sources, can be added to the power grid in times of power shortage, or replaced with new feeder lines in times of failure. CN102938564B introduces a closed-loop flexible power distribution system based on DC current. However, such methods are inconvenient in practice because they typically rely on specific configurations of the power grid and devices. SUMMARY

[0005] Example embodiments of the present disclosure propose a solution for interconnecting feeder lines in a power grid.

[0006] In a first aspect, example embodiments of the present disclosure provide a modular interconnection device. The modular interconnection device includes a modular port assembly, a node, a converter, and a local controller. The modular port assembly is configured to deliver alternating current and / or direct current. The node is coupled to an AC source via a first switch and the modular port assembly. The first switch is configured to selectively disconnect the modular interconnection device from the AC source. The converter is coupled to the node via a second switch and to a DC source via a third switch. The converter is configured to convert AC current to DC current or DC current to AC current. The local controller is coupled to the first switch, the second switch, and the third switch, and is configured to control operation of the first switch, the second switch, and the third switch.

[0007] In some embodiments, the modular interconnection device is configured to be coupled to another modular interconnection device, and to deliver or receive electricity from the other modular interconnection device. The local controller of the modular interconnection device is configured to communicate with the local controller of the other modular interconnection device or a control center of a power source network.

[0008] In some embodiments, the first switch is coupled between the modular port assembly and the node.

[0009] In some embodiments, the node is also coupled to the modular port assembly via a fourth switch or directly. The local controller is also coupled to the fourth switch and configured to control operation of the fourth switch.

[0010] In some embodiments, the modular port assembly includes a first port, a second port, a third port, and a fourth port. The first port is coupled to the first switch and configured to receive or deliver AC current from or to the AC source. The second port is coupled to the node directly or via a fourth switch and configured to selectively deliver AC current between modular interconnection devices. The third port is coupled to the third switch and configured to selectively deliver DC current between modular interconnection devices. The fourth port is coupled to the node and configured to deliver AC current between modular interconnection devices.

[0011] In some embodiments, the modular interconnection device also includes a fifth switch. The fifth switch is coupled to the cable and the local controller and configured to selectively disconnect the cable from the DC source.

[0012] In some embodiments, the local controller is integrated in the converter.

[0013] In some embodiments, the local controller is also configured to turn off the first switch in response to receiving information indicating a failure of the AC source.

[0014] In some embodiments, the local controller is also configured to turn off the second switch in response to receiving information indicating a failure of the converter.

[0015] In some embodiments, the local controller is also configured to turn on the third switch in response to receiving a request to deliver DC current from the modular interconnection device to another modular interconnection device or receiving a request to receive DC current from the another modular interconnection device to the modular interconnection device.

[0016] In some embodiments, the local controller is also configured to turn on the fourth switch in response to receiving a request to deliver AC current from another AC source or another converter.

[0017] In some embodiments, the local controller is also configured to turn on the fourth switch and turn off the first switch in response to receiving a request to convert reactive AC current from another AC source.

[0018] In some embodiments, the modular interconnect apparatus further includes a fifth switch. The fifth switch is coupled to the converter and configured to disconnect the converter from the DC source. The modular port assembly includes a fifth port coupled to the fifth switch, the fifth port configured to transport DC current between modular interconnect apparatuses. The local controller is further coupled to the fifth switch and configured to control operation of the fifth switch.

[0019] In some embodiments, the local controller is further configured to turn on the fifth switch in response to a request to receive DC current from or to transport DC current to another modular interconnect apparatus.

[0020] In some embodiments, the local controller is further configured to control the converter to receive or transport DC current based on a load redistribution request.

[0021] In a second aspect, example embodiments of the present disclosure provide a power grid system. The power grid system includes a first modular interconnect apparatus according to the first aspect and a second modular interconnect apparatus according to the first aspect, the second modular interconnect apparatus selectively coupled to the first modular interconnect apparatus and configured to transport electrical energy between the first modular interconnect apparatus and the second modular interconnect apparatus.

[0022] In some embodiments, the second port of the first modular interconnect apparatus is selectively coupled to the fourth port of the second modular interconnect apparatus.

[0023] In some embodiments, the third port of the first modular interconnect apparatus is selectively coupled to the third port of the second modular interconnect apparatus.

[0024] In some embodiments, the power grid system further includes a third modular interconnect apparatus according to the first aspect, the second and fourth ports of the first, second, and third modular interconnect apparatuses coupled in a ring topology.

[0025] In some embodiments, the third ports of the first, second, and third modular interconnect apparatuses are coupled to a common node.

[0026] In some embodiments, the third and fifth ports of the first modular interconnect apparatus according to claim 11, the second modular interconnect apparatus according to claim 10, and the third modular interconnect apparatus according to claim 11 are coupled in a ring topology.

[0027] In some embodiments, the power grid system further includes an energy storage device coupled to a third port of the first modular interconnection device or the second modular interconnection device.

[0028] According to embodiments of the present disclosure, the power grid system can be easily configured, and the reliability of the power grid system can be improved with the modular interconnection device. BRIEF DESCRIPTION OF DRAWINGS

[0029] The above and other objects, features and advantages of the example embodiments disclosed herein will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0030] Figure 1 A block diagram of a power grid system according to some example embodiments of the present disclosure is shown;

[0031] Figure 2 A block diagram of a modular interconnection device according to some example embodiments of the present disclosure is shown;

[0032] Figure 3 A block diagram of a modular interconnection device according to some other example embodiments of the present disclosure is shown;

[0033] Figure 4 A block diagram of a modular interconnection device according to some other example embodiments of the present disclosure is shown;

[0034] Figure 5 A block diagram of a power grid system of two MIDs according to some example embodiments of the present disclosure is shown;

[0035] Figure 6 A block diagram of a power grid system of two MIDs according to some other example embodiments of the present disclosure is shown;

[0036] Figure 7 A block diagram of a power grid system of three MIDs according to some example embodiments of the present disclosure is shown;

[0037] Figure 8 A block diagram of a power grid system of four MIDs according to some example embodiments of the present disclosure is shown;

[0038] Figure 9 A block diagram of a power grid system of five MIDs according to some example embodiments of the present disclosure is shown;

[0039] Figure 10 A block diagram of a power grid system of four MIDs according to some other example embodiments of the present disclosure is shown;

[0040] Figure 11a block diagram of a power grid system of four MIDs according to some other example embodiments of the disclosure is shown;

[0041] Figure 12 a block diagram of a power grid system of four MIDs with energy storage according to some example embodiments of the disclosure is shown;

[0042] Figure 13 a block diagram of a power grid system of five MIDs with energy storage according to some example embodiments of the disclosure is shown;

[0043] Figure 14 a block diagram of a power grid system of multiple MIDs according to some example embodiments of the disclosure is shown;

[0044] Figure 15 a block diagram of a modular interconnect device according to some other example embodiments of the disclosure is shown;

[0045] Figure 16 a block diagram of a power grid system of two Figure 15 MIDs according to some example embodiments of the disclosure is shown;

[0046] Figure 17 a block diagram of a power grid system of three Figure 15 MIDs according to some example embodiments of the disclosure is shown;

[0047] Figure 18 a block diagram of a power grid system of four Figure 15 MIDs according to some example embodiments of the disclosure is shown.

[0048] Throughout the drawings, identical or corresponding reference numbers designate identical or corresponding parts. DETAILED DESCRIPTION

[0049] The subject matter described herein will now be discussed with reference to several example embodiments. The discussion of these embodiments is merely meant to provide a better understanding of the subject matter described herein, and is not meant to suggest any limitation as to the scope of the subject matter.

[0050] The terms “comprises” or “comprising,” and variations thereof, are to be construed as open-ended terms meaning that the comprising step is not exclusive of additional steps. The term “or” should be construed as “and / or” unless context clearly indicates otherwise. The term “based on” should be interpreted as “based, at least in part, on” The term “operable to” should refer to functionality that can be caused by an operation by a user or external mechanism. The terms “one embodiment” and “an embodiment” should not be construed as “the only embodiment.” The term “another embodiment” should not be construed as “the only other embodiment.”

[0051] Unless otherwise stated or limited, the terms "mount," "connect," "support," and "couple" and variations thereof are used broadly and encompass both direct and indirect mount, connection, support, and coupling. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings. In the description below, like reference numerals and letters are used to describe like, similar, or corresponding parts in the accompanying drawings. The following detailed description can include other explicit and implicit definitions.

[0052] As described above, conventional power grid systems are inconvenient to configure because various feeders of various characteristics can be coupled to the power grid system, and the conventional power grid system needs to consider inherent characteristics of the various feeders when merging the feeders. In addition, the conventional power grid system can suffer from a complete collapse when a global control center of the power grid system fails. Therefore, it is desirable to facilitate configuration of the power grid system and improve stability of the conventional power grid system.

[0053] Figure 1 A block diagram of a power grid system 1 is shown in accordance with some example embodiments of the present disclosure. The power grid system 1 includes a plurality of modular interconnection devices (MIDs) 10, each of which includes a local controller. The term "modular interconnection device" herein refers to interconnection devices having similar or identical architectures, which include port components that implement similar or identical interconnection functions, and can be coupled and replaced with each other. The term "local controller" herein refers to a controller in a MID device, rather than a global controller shared by conventional power grid systems.

[0054] The MIDs 10 can be coupled to AC power sources. Although Figure 1 Each of the MIDs in the power grid system 1 is shown as being coupled to an AC power source, but this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. For example, a MID can share an AC power source via another MID. In one example, Figure 1 The MID 2 in the power grid system 1 can be disconnected from the power source AC2 and share the power source AC1 with the MID 1. Details of the interconnection will be described below.

[0055] The power grid system 1 includes a global AC network control center 2. The control center 2 can collect information from a plurality of MIDs or other sensing nodes in the power grid system and control operations of the MIDs by sending instructions to the MIDs. In the event that the power grid system 1 needs another MID, then the AC network control center 2 can control certain MIDs (typically the MIDs that will be coupled with the other MID) to temporarily disable the MIDs, and enable the disabled MIDs and the other MID when the other MID is successfully coupled to the disabled MIDs.

[0056] In the event that a certain MID needs to be removed from the power grid system 1, the AC network control center 2 can control certain MIDs (typically the MIDs to which the MID will be coupled) to temporarily disable the MIDs, and enable the disabled MIDs upon successful coupling of the disabled MIDs and / or incorporation of new MIDs. In the event that the global AC network control center 2 fails or loses communication with the MIDs, at least one of the controllers in the MIDs can operate a temporary master controller, and the other controllers can communicate with the master controller to enable the power grid system 1 to function properly.

[0057] By incorporating local controllers in the MIDs, the MIDs can function properly even if the global AC network control center fails. Furthermore, the power grid system will not completely collapse even if a certain or certain ones of the controllers of the MIDs fail.

[0058] Furthermore, conventional methods include only one global network control center, which is often located far from the feed lines. Thus, conventional methods are unable to provide a fast or immediate response to changes in the power grid due to the long communication distance and heavy communication traffic load.

[0059] By providing local controllers in the MIDs, the local controllers can manage the MIDs without having to transmit all information to the global AC network control center. This will significantly reduce the communication traffic load, and a fast or immediate response to changes in the power grid can be achieved due to the short communication distance. In some cases, there is no communication outside the MIDs. Furthermore, more comprehensive and flexible MIDs operations can be achieved with the local controllers, as described below.

[0060] Figure 2 A block diagram of a modular interconnect device 10 is shown in accordance with some example embodiments of the present disclosure. The modular interconnect device 10 includes a first switch 12, a second switch 13, a third switch 15, a fourth switch 14, a local controller 18, an AC / DC converter 16, and a port assembly 20. Although the first, second, third, and fourth switches are shown in the modular interconnect device 10, this is for illustration only and does not imply any limitation on the scope of the subject matter described herein. Some of the switches can be independently provided and outside the modular interconnect device 10. For example, the first switch can be provided outside the modular interconnect device 10 and coupled between the first port 21 of the port assembly 20 and an AC power source.

[0061] The port assembly 20 includes a first port 21, a second port 22, a third port 23, and a fourth port 24. Although four ports are shown in the Figure 2 port assembly, this is for illustration only and does not imply any limitation on the scope of the subject matter described herein. More or fewer ports can be provided in the port assembly. For example, Figure 15A port assembly including five ports is shown, which will be described below. Although four ports are shown in the single-port assembly 20 in Figure 2

[0062] The local controller 18 is configured to collect information of the status of the MID, including power status, switch status, etc., and control the operation of the switches. In addition, the local controller 18 can also control the operation of the AC / DC converter 16. Although the local controller 18 is shown separately, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. For example, to save cost, the local controller 18 can be incorporated into the controller of the AC / DC converter 16.

[0063] The AC / DC converter 16 is configured to convert AC current to DC current or DC current to AC current. For example, in the case of converting AC current to DC current, the AC / DC converter 16 can receive AC current via the first port 21, the on switch 12, the node N0, and the on switch 13, and convert the AC current to DC current. Then, the DC current can be delivered to other MIDs via the on switch 15. For example, in the case of converting DC current to AC current, the AC / DC converter 16 can receive DC current via the on switch 15, and convert the DC current to AC current. Then, the AC current can be delivered to other MIDs via the on switch 13, the node N0, the on switch 12, and the first port 21. Although two general conversion methods are described, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. Details of the conversion and delivery will be described below.

[0064] The first switch 12 is coupled to the AC source and configured to selectively deliver AC current. In addition, the first switch 12 is also configured to disable the MID 10 or isolate the MID 10 from the AC source in the case of replacing the MID 10 or the AC source or the MID 10 fails. The second switch 13 is coupled between the node N0 and the AC / DC converter 16 and configured to selectively conduct AC current in the case of the AC / DC converter 16 fails, and disable the converter 16 or isolate the converter 16 from the MID 10.

[0065] ​The third switch 15 is coupled between the AC / DC converter 16 and the third port 23 and is configured to selectively conduct DC current and isolate the DC link between the MID 10 and other MIDs. The fourth switch 14 is coupled between the node N0 and the second port 22 and is configured to selectively conduct AC current with another MID. The fourth switch 14 is typically a normally open point (NOP) switch. Although the fourth switch 14 is shown in the MID 10, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. For example, the MID 10 can omit the fourth switch 14 by directly connecting the node N0 to the second port 22, and a conventional NOP switch can be coupled to the second port 22 of the MID 10 and controlled by the local controller 18 of the MID 10.

[0066] In addition, the node N0 can be directly coupled to the fourth port 24 and configured to deliver AC current between different MIDs. Although the node N0 is shown as directly coupled to the fourth port 24, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. For example, the node N0 can be coupled to the fourth port 24 via another switch, and the local controller 18 controls the operation of the other switch.

[0067] Figure 3 A block diagram of the modular interconnection device 10 is shown in accordance with some other example embodiments of the present disclosure. In addition to incorporating a fifth switch S0, Figure 3 The MID 10 in Figure 2 is similar to the MID 10 in The fifth switch S0 can be disposed independently of the MID 10 and controlled by the local controller 18 via cable communication or wirelessly. The fifth switch S0 is coupled to the cable for delivering DC current and configured to selectively disconnect the cable from the power grid (due to potential energy loss).

[0068] Figure 4 A block diagram of the modular interconnection device 10 is shown in accordance with some other example embodiments of the present disclosure. In addition to the location of the fourth switch 14, Figure 4 The MID 10 in Figure 2 is similar to the MID 10 in In Figure 4 , the fourth switch 14 is located outside of the MID 10. The fourth switch 14 can be disposed independently of the MID 10 but controlled by the local controller 18. As an alternative, the fourth switch 14 can be provided by a conventional NOP switch that exists in the power grid system.

[0069] Details of the operation of the MIDs and the configuration of the power grid system will be described below. Figure 5A block diagram of a power grid system of two MIDs is shown in accordance with some example embodiments of the present disclosure. The power grid system can include at least two MIDs, and feeder lines can be interconnected by coupling ports of the MIDs appropriately. MIDs M1 and M2 can be instances of the MID 10 in Figure 2 It can be appreciated that, Figure 3 and Figure 4 The MID 10 in Figure 5 can also apply to the configuration of

[0070] The MID M1 including four ports is coupled to the MID M2 including four ports via cables C1, C2, and C3. The cables C1, C2, and C3 can include long distance cables for transporting electric current. An AC source PS1 is coupled to the first port of the MID M1, and an AC source PS2 is coupled to the first port of the MID M2. The second port of the MID M1 is coupled to the fourth port of the MID M2 via the cable C1, and the fourth port of the MID M1 is coupled to the second port of the MID M2 via the cable C3. The third port of the MID M1 is coupled to the third port of the MID M2 via the cable C2.

[0071] Although the AC source PS1 is shown as being coupled directly to the first port of the MID M1, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. For example, the AC source PS1 can be coupled to the first port of the MID M1 via a first switch disposed outside the MID M1. Similarly, the AC source PS2 can be coupled to the first port of the MID M2 via a first switch.

[0072] Although the second port of the MID M1 is shown as being coupled directly to the cable C1, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. For example, the second port of the MID M1 can be coupled to the cable C1 via a fourth switch disposed outside the MID M1. Similarly, the second port of the MID M2 can be coupled to the cable C3 via a fourth switch.

[0073] Generally, the fourth switches in the MIDs M1 and M2 are NOP switches, and there is no AC current transportation between the MIDs M1 and M2. However, in some cases, AC current needs to be transported between the MIDs M1 and M2.

[0074] For example, in the event of a failure of the AC source PS2, the local controller 18 of the MID M2 turns off the first switch 12 in response to receiving information indicating the failure of the AC source PS2. In addition, the fourth switch of the MID Ml can be turned on by the local controller 18 of the MID Ml so that AC current from the AC source PS 1 can be delivered to the AC / DC converter 16 via the fourth switch 14 of the MID Ml and the node N0 or to the AC source PS2 via the node N0 of the MID M2.

[0075] In addition, in the event of a failure of the AC source PS 1, the local controller 18 of the MID Ml turns off the first switch 12 in response to receiving information indicating the failure of the AC source PS 1. In addition, the fourth switch of the MID M2 can be turned on by the local controller 18 of the MID M2 so that AC current from the AC source PS2 can be delivered to the AC / DC converter 16 via the fourth switch 14 of the MID M2 and the node N0 or to the AC source PS 1 via the node N0 of the MID Ml.

[0076] In the event of a failure of the AC / DC converter 16 of the MID M2, the local controller 18 of the MID M2 turns off the second switch 13 in response to receiving information indicating the failure of the converter 16. In addition, if the second switch 15 is not turned off, the local controller 18 of the MID M2 can turn off the second switch 15 of the MID M2 in response to receiving information indicating the failure of the converter 16. In addition, the fourth switch 14 of the MID M2 can be turned on by the local controller 18 of the MID M2 so that AC current from the AC source PS2 can be shared by the MID Ml.

[0077] In the event of a failure of the AC / DC converter 16 of the MID Ml, the local controller 18 of the MID Ml turns off the second switch 13 in response to receiving information indicating the failure of the converter 16. In addition, if the second switch 15 is not turned off, the local controller 18 of the MID Ml can turn off the second switch 15 of the MID Ml in response to receiving information indicating the failure of the converter 16. In addition, the fourth switch 14 of the MID Ml can be turned on by the local controller 18 of the MID Ml so that AC current from the AC source PS 1 can be shared by the MID M2.

[0078] In case a DC current is to be delivered from MID Ml to MID M2, MID M2 can send a request to the global AC network control center 2 or to MID Ml to deliver a DC current from MID Ml to MID M2, and can turn on the third switch 15 of MID M2 after sending the request. The local controller 18 of MID Ml turns on the third switch 15 of MID Ml in response to receiving the request to deliver a DC current from MID Ml to MID M2.

[0079] As an alternative, MID Ml can send a request to the global AC network control center 2 or to MID M2 to receive a DC current from MID M2 to MID Ml, and can turn on the third switch 15 of MID Ml after sending the request. The local controller 18 of MID M2 turns on the third switch 15 of MID M2 in response to receiving the request to deliver a DC current from MID M2 to MID Ml.

[0080] In one example, a predetermined amount of electrical energy is to be delivered from MID Ml to MID M2, the local controller 18 of MID Ml controls the second switch 13 and the third switch 15 of MID Ml to turn on based on a request from MID M2, converts the predetermined amount of electrical energy from AC to DC, and delivers the predetermined electrical energy to MID M2 via cable C2, MID M2 having turned on the third switch 15 of MID M2 to receive the electrical energy.

[0081] Similarly, a predetermined amount of electrical energy is to be delivered from MID M2 to MID Ml, the local controller 18 of MID M2 controls the second switch 13 and the third switch 15 of MID M2 to turn on based on a request from MID Ml, and converts the predetermined amount of electrical energy from AC to DC, and then delivers the predetermined electrical energy to MID Ml via cable C2, MID Ml having turned on the third switch 15 of MID Ml to receive the electrical energy.

[0082] It is to be understood that the above examples are described for the active mode. In the reactive mode, Figure 5 the configuration of FIG. 1 also applies. For example, in case of a failure of AC source PS2, the local controller 18 of MID M2 turns off the first switch 12 of MID M2 and turns on the second switch 13 of MID M2. The local controller 18 of MID Ml turns on the first switch 12, the second switch 13, and the fourth switch 14 of MID Ml and turns off the third switch 15 of MID Ml. In this case, the system of two MIDs can operate in the reactive mode even if one of the AC sources fails.

[0083] In another example, in the event of a failure of the AC / DC converter 16 of the MID Ml, the local controller 18 of the MID Ml turns on the first switch 12 and the fourth switch 14 of the MID Ml, and turns off the second and third switches of the MID Ml. The local controller 18 of the MID M2 turns on the second switch 13 of the MID M2, and turns off the first switch 12 of the MID M2. In this case, the system of two MIDs can operate in the reactive mode even if one of the AC / DC converters fails.

[0084] It can be seen that since all MIDs are modular and controlled by respective local controllers, the MIDs and the system configured with the MIDs herein are easy to implement and can be applied to both active and reactive modes. In practical applications, it is only necessary to connect the port assemblies correctly.

[0085] Although only two MIDs are shown in Figure 5 , this is only for illustration and does not imply any limitation on the scope of the subject matter described herein. For example, the two MIDs can send operating conditions to the global AC network control center 2, and operate based on instructions from the global AC network control center 2. For example, the global AC network control center 2 can instruct the MID Ml to deliver a predetermined amount of electrical energy to the MID M2 based on load information sent from the MIDs to the global AC network control center 2.

[0086] In another example, the global AC network control center 2 can instruct the MID Ml to share the AC source PSl with the MID M2 based on failure information of the AC source PS2 sent from the MID M2 to the global network controller. In yet another example, the global AC network control center 2 can receive a request from the MID Ml requiring a predetermined amount of electrical energy, and the global AC network control center 2 can instruct the MID M2 to provide the predetermined amount of electrical energy to the MID Ml via the cable C2.

[0087] Figure 6 A block diagram of a power grid system of two MIDs according to some other example embodiments of the present disclosure is shown. In addition to the AC cable link between the two MIDs, Figure 6 is configured similarly to Figure 5 . Therefore, for the sake of brevity, the description of similar features will be omitted herein.

[0088] The second port 21 of the MID Ml is coupled with the second port 21 of the MID M2 via the long distance cable CI. Figure 6 The configuration of Figure 5Two long distance cables are shown in the configuration of FIG. 1, but only one cable is sufficient, and the other cable can be used as a backup cable. In this case, the operations described above for Figure 5 the configuration of FIG. 1 can be applied to Figure 6 the configuration of FIG. 2.

[0089] Figure 7 A block diagram of a power grid system of three MIDs is shown in accordance with some example embodiments of the present disclosure. Figure 7 The configuration of FIG. 2 can be extended from Figure 5 a system of two MIDs. For example, in the case where a new feeder needs to be incorporated into Figure 5 the system of FIG. 2, the local controller can temporarily suspend operation by turning off all switches. Then, an operator can disconnect some connections between MIDs M1 and M2, and couple MID M3 to MIDs M1 and M2.

[0090] It can be seen that the operator only needs to disconnect the original cables from the ports and then couple the cables to the correct ports of the MIDs when extending the power grid system. Therefore, the operator can easily operate in the field. The power grid system can include three MIDs, and the feeders can be interconnected by coupling the ports of the MIDs appropriately. MIDs M1, M2, and M3 can be instances of the MID 10 in Figure 2 It can be understood that Figure 3 and Figure 4 the MID 10 in FIG. 2 can also be applied to Figure 7 the configuration of FIG. 3.

[0091] The second port of the MID M1 is coupled to the fourth port of the MID M2, the second port of the MID M2 is coupled to the fourth port of the MID M3, and the second port of the MID M3 is coupled to the fourth port of the MID M1. It can be seen that the second and fourth ports of the first MID M1, the second MID M2, and the third MID M3 are coupled in a ring topology.

[0092] The first port of each of the MIDs M1, M2, and M3 is coupled to a respective AC source. The third ports of the MIDs M1, M2, and M3 are coupled to a common node N1 via a serial connection of long distance cables and switches controlled by respective local controllers. The switches in the serial connection can be instances of the fifth switch S0 in Figure 3 With this configuration, AC current can be delivered on the cables C11, C12, and C13 as needed, and DC current can be delivered on the cables C21, C22, and C23 as needed.

[0093] For example, in the event of a failure of AC source PS3, the AC / DC converter of MID M3 can receive AC current from AC sources PS1 and PS2 by turning off the first switch of MID M3 and turning on the second and fourth switches of MID M3 and the fourth switch of MID M2.

[0094] In the event of a failure of the AC / DC converter of MID M3, the AC / DC converters of MIDs M1 and M2 can receive AC current from AC source PS3 by turning off the second and third switches of MID M3 and turning on the first and fourth switches of MID M3 and the fourth switch of MID M2. In the event that a first predetermined amount of electrical energy is to be delivered from MID M1 to MID M3 and a second predetermined amount of electrical energy is to be delivered from MID M2 to MID M3, switches S21, S22, and S23 can be turned on by the respective local controllers so that the first and second amounts of electrical energy can be delivered from the AC / DC converters of MIDs M1 and M2 to the AC / DC converter of MID M3.

[0095] It should be understood that the above examples are described for the active mode. In the reactive mode, Figure 7 the configurations of FIGS. 1-3 also apply. For example, turn off the first switches of the second and third MIDs M2 and M3 and turn on the first switch of the first MID M1. Turn on the second switches of the second and third MIDs M2 and M3 and turn off the second switch of the first MID M1. Turn on all of the fourth switches of MIDs M1-M3 and turn off all of the third switches of MIDs M1-M3. In this case, all of the AC / DC converters in the grid system are coupled to AC source PS1 and can operate in a static synchronous compensator (STATCOM) reactive mode.

[0096] Although the reactive mode is described with reference to a two-MID system of Figure 5 and a three-MID system of Figure 7 , this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. It can be appreciated that reactive operation, such as STATCOM operation, can be extended to grid systems including more MIDs by selectively operating the switches to couple more AC / DC converters to one AC source.

[0097] Although certain aspects of a three-MID system have been described with reference to Figure 7 , this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. Features described for a two-MID grid system can be similarly applied to a three-MID grid system by appropriately turning on / off the switches.

[0098] Figure 8 A block diagram of a power grid system of four MIDs is shown in accordance with some example embodiments of the present disclosure. Figure 8 The configuration of Figure 7 three MIDs can be extended. For example, in case a new feeder needs to be incorporated into Figure 7 the system of

[0099] It can be seen that the operator only needs to disconnect the original cables from the ports and then couple the cables to the correct ports of the MIDs when extending the power grid system. Therefore, the operator is easily operated in the field. The power grid system can include four MIDs, and the feeders can be interconnected by coupling the ports of the MIDs appropriately. The MIDs M1, M2, M3, and M4 can be instances of the MID 10 in Figure 2 It can be understood that Figure 3 and Figure 4 the MID 10 in Figure 8 can also apply to the configuration of

[0100] The second port of the MID M1 is coupled to the fourth port of the MID M4, the second port of the MID M4 is coupled to the fourth port of the MID M2, the second port of the MID M2 is coupled to the fourth port of the MID M3, and the second port of the MID M3 is coupled to the fourth port of the MID M1. It can be seen that the second and fourth ports of the first MID M1, the second MID M2, the third MID M3, and the fourth MID M4 are coupled in a ring topology for delivering AC current between these feeders.

[0101] The first port of each of the MIDs M1, M2, M3, and M4 is coupled to a respective AC source. The third ports of the first MID M1, the second MID M2, the third MID M3, and the fourth MID M4 are coupled to a common node N1 via a serial connection of long distance cables and switches controlled by respective local controllers. The switches in the serial connection can be instances of the fifth switch S0 in Figure 3 With this configuration, AC current can be selectively delivered on the cables C11, C12, C13, and C14 as needed, and DC current can be selectively delivered on the cables C21, C22, C23, and C24 as needed.

[0102] For example, in the event of a failure of AC source PS3, the AC / DC converter of MID M3 can receive AC current from AC sources PS1 and PS2 by turning off the first switch of MID M3 and turning on the second and fourth switches of MID M3 and the fourth switch of MID M2, and turning off the second switches of MIDs M1 and M4.

[0103] In the event of a failure of the AC / DC converter of MID M3, the AC / DC converters of MIDs M1 and M2 can receive AC current from AC source PS3 by turning off the second and third switches of MID M3 and turning on the first and fourth switches of MID M3 and the fourth switch of MID M2, and turning off the fourth switches of MIDs M1 and M4. In the event that a first predetermined amount of electrical energy needs to be delivered from MID M1 to MID M3 and a second predetermined amount of electrical energy needs to be delivered from MID M2 to MID M3, switches S21, S22, and S23 can be turned on by the respective local controllers and switch S24 can be turned off by the local controller of MID M4, such that the first and second amounts of electrical energy can be delivered from the AC / DC converters of MIDs M1 and M2 to the AC / DC converter of MID M3 without flowing into the AC / DC converter of MID M4.

[0104] Although some aspects of a system of four MIDs have been described with reference to Figure 8 two or three MIDs, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. Features described for a power grid system of two or three MIDs can be similarly applied to a power grid system of four MIDs by appropriately turning on / off the switches.

[0105] Figure 9 A block diagram of a power grid system of five MIDs according to some example embodiments of the present disclosure is shown. Figure 9 The configuration of the power grid system of five MIDs can be extended from Figure 8 the system of three MIDs. For example, in the event that a new feeder needs to be incorporated into the system of three MIDs, the local controllers can temporarily suspend operation by turning off all switches. An operator can then disconnect some of the connections between MIDs M1, M2, M3, and M4, and couple MID M5 to MIDs M1, M2, M3, and M4. Figure 8

[0106] It can be seen that the operator only needs to disconnect the original cables from the ports and then couple the cables to the correct ports of the MIDs when extending the power grid system. Thus, the operator is easily operated in the field. The power grid system can include four MIDs, and the feeders can be interconnected by appropriately coupling the ports of the MIDs. MIDs M1, M2, M3, M4, and M5 can be Figure 2 ​MID 10 in FIG. 1. It can be appreciated that Figure 3 and Figure 4 MID 10 in FIG. 1. It can be appreciated that Figure 9 the configuration of FIG. 1.

[0107] The second port of the MID M1 is coupled to the fourth port of the MID M4, the second port of the MID M4 is coupled to the fourth port of the MID M5, the second port of the MID M5 is coupled to the fourth port of the MID M2, the second port of the MID M2 is coupled to the fourth port of the MID M3, and the second port of the MID M3 is coupled to the fourth port of the MID M1. It can be seen that the second and fourth ports of the first, second, third, and fourth MIDs M1, M2, M3, M4, and M5 are coupled in a ring topology for transporting AC current among these feeders.

[0108] The first port of each of the MIDs M1, M2, M3, M4, and M5 is coupled to a respective AC source. The third ports of the first, second, third, and fourth MIDs M1, M2, M3, M4, and M5 are coupled to a common node N1 via a serial connection of long distance cables and switches controlled by respective local controllers. The switches in the serial connection can be examples of the fifth switches S0 in FIG. 1. With this configuration, AC current can be selectively transported on the cables C11, C12, C13, C14, and C15, and DC current can be selectively transported on the cables C21, C22, C23, C24, and C25 as needed. Figure 3

[0109] For example, in the event of a failure of the AC source PS3, the AC / DC converter of the MID M3 can receive AC current from the AC sources PS1 and PS2 by turning off the first switch of the MID M3 and turning on the second and fourth switches of the MID M3 and the fourth switch of the MID M2 to turn off the second switches of the MIDs M1, M4, and M5.

[0110] In the event of a failure of the AC / DC converter of the MID M3, the AC / DC converters of the MIDs M1 and M2 can receive AC current from the AC source PS3 by turning off the second and third switches of the MID M3 and turning on the first and fourth switches of the MID M3 and the fourth switch of the MID M2 to turn off the fourth switches of the MIDs M1, M4, and M5.

[0111] ​In the case where a first predetermined amount of electrical energy needs to be delivered from MID Ml to MID M3, and a second predetermined amount of electrical energy needs to be delivered from MID M2 to MID M3, switches S21, S22, and S23 can be turned on by the respective local controllers, and switches S24 and S25 can be turned off by the local controllers of MIDs M4 and M5, such that the first and second amounts of electrical energy can be delivered from the AC / DC converters of MIDs Ml and M2 to the AC / DC converter of MID M3 without flowing into the AC / DC converters of MIDs M4 and M5.

[0112] Although the description has been directed to Figure 9 described for a system of five MIDs, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. Features described for a power grid system of two MIDs, three MIDs, or four MIDs can be similarly applied to a power grid system of five MIDs by appropriately turning on / off the switches.

[0113] Although Figure 5 to Figure 9 power grid systems of two MIDs, three MIDs, four MIDs, and five MIDs are shown in

[0114] Figure 10 A block diagram of a power grid system of four MIDs is shown in accordance with some other example embodiments of the present disclosure. In addition to the DC links between the MIDs, Figure 10 The power grid system of four MIDs in Figure 8 is similar to the power grid system of four MIDs in

[0115] The third ports of the first and second MIDs Ml and M2 are coupled to a first common node Nl, and the third ports of the third and fourth MIDs M3 and M4 are coupled to a second common node N2. The first and second common nodes Nl and N2 are coupled to each other via switches S25 and S26 and a long distance cable S26. The switches S25 and S26 can be controlled by either the MID Ml-M4 local controllers or the AC network control center 2. With this configuration, MIDs Ml and M2 form a first DC pair, and MIDs M3 and M4 form a second DC pair.

[0116] In one example, a first DC current can be delivered between the MIDs of the first DC pair, and a second DC current can be delivered between the MIDs of the second DC pair in parallel with the first DC current. In another example, DC current can be delivered from any MID to any other MID as long as the DC switches are operated properly. With the addition of the second node, the DC current distribution can be more flexible.

[0117] Figure 11 A block diagram of a power grid system of four MIDs is shown in accordance with some other example embodiments of the present disclosure. In addition to the DC links between the MIDs, Figure 11 The power grid system of four MIDs in Figure 10 The power grid system of four MIDs in

[0118] The third ports of the first and second MIDs M1 and M2 are coupled to a first common node N1, and the third ports of the third and fourth MIDs M3 and M4 are coupled to a second common node N2. The first and second common nodes N1 and N2 are coupled to each other via a switch S25. The switch S25 can be controlled by either the local controllers of the MIDs M1-M4 or the AC network control center 2. With this configuration, the MIDs M1 and M2 form a first DC pair, and the MIDs M3 and M4 form a second DC pair. In Figure 11 In the configuration of

[0119] In one example, a first DC current can be delivered between the MIDs of the first DC pair, and a second DC current can be delivered between the MIDs of the second DC pair in parallel with the first DC current. In another example, DC current can be delivered from any MID to any other MID as long as the DC switches are operated properly. With the addition of the second node, the DC current distribution can be more flexible.

[0120] Figure 12 A block diagram of a power grid system of four MIDs with energy storage is shown in accordance with some example embodiments of the present disclosure. In addition to the energy storages E1 and E2, Figure 12 The power grid system of four MIDs in Figure 11 The power grid system of four MIDs in

[0121] The energy storage E1 and E2 can be devices for storing DC energy, such as batteries. The first energy storage E1 is shared by the first DC pair, and the second energy storage E2 is shared by the second DC pair. In addition, the first energy storage E1 can be shared by the second DC pair by turning on the switch S25. Similarly, the second energy storage E2 can be shared by the first DC pair by turning on the switch S25.

[0122] By providing energy storage devices, it can help the power distribution network to achieve energy management and power flow optimization, as excess energy can be stored into the energy storage devices and can be released into the DC grid when needed.

[0123] Figure 13 A block diagram of a power grid system with five MIDs with energy storages according to some example embodiments of the present disclosure is shown. Except for incorporating a fifth intermediate M5, Figure 12 The power grid system with four MIDs in Figure 11 is similar to the power grid system with four MIDs in

[0124] In the configuration of Figure 13 , the MIDs M1, M2, and M5 form the first DC pair, and the energy storage E1 is shared by the MIDs M1, M2, and M5. In addition, the first energy storage E1 can be shared by the second DC pair by turning on the switch S25. Similarly, the second energy storage E2 can be shared by the first DC pair by turning on the switch S25.

[0125] Although Figure 5 to Figure 13 various configurations of the power grid system are shown, this is for illustration only and not to imply any limitation on the scope of the subject matter described herein. It should be appreciated that other configuration topologies are possible.

[0126] For example, Figure 14 A block diagram of a power grid system with multiple MIDs according to some example embodiments of the present disclosure is shown. The power grid system includes a first subsystem and a second subsystem. The first subsystem is coupled to the second subsystem via switches S11 and S12 and a long distance cable C14 for a DC link.

[0127] The first subsystem includes MID 1, MID 2,... MID K, where K represents a number greater than 2. The MIDs in the first subsystem can be physically close to each other and coupled in series, such that AC current can be transported within the first subsystem, and DC current can be transported between the first subsystem and the second subsystem.

[0128] The second subsystem includes MID A, MID B, MID M... MID N, where M represents a number greater than 0, and N represents a number greater than N. The third port of the MID in the second subsystem is coupled to the common node N2, while the second port and the fourth port of the MID in the second subsystem are coupled in series to share the AC source if necessary.

[0129] Figure 15 A block diagram of a MID 9 is shown in accordance with some other example embodiments of the present disclosure. The MID 9 is similar to the MID 10 in Figure 2 , except that the fifth port 25 and the fifth switch 17 are incorporated. Therefore, the description of similar features will be omitted here for brevity. Both the third switch 15 and the fifth switch 17 are coupled to the AC / DC converter 16 to deliver DC current, and the port assembly 20 can include the fifth port 25. By providing the fifth switch 17 and the fifth port 25, the flexibility of the DC link configuration will be improved, as described below with reference to Figure 16 to Figure 18 .

[0130] Figure 16 A block diagram of a power grid system of two Figure 15 MIDs is shown in accordance with some example embodiments of the present disclosure. The first port of the first MID M1 and the second port of the second MID M2 are coupled to the AC sources PS1 and PS2, respectively. To selectively deliver AC current, the second port of the first MID M1 is coupled to the fourth port of the second MID M2, and the fourth port of the first MID M1 is coupled to the second port of the second MID M2. It can be appreciated that one AC link between the two MIDs of the system is sufficient, and the other AC link can be a backup AC link.

[0131] The third port of the MID M1 is coupled to the third port of the MID M2 via the cable C2, and the fifth port of the MID M1 is coupled to the fifth port of the MID M2 via the cable C3. Therefore, two DC links are formed between the first MID M1 and the second MID M2. By providing two DC links, the delivery efficiency can be improved in the case that both of the two DC links are used to deliver DC current.

[0132] Figure 17 A block diagram of a power grid system of three Figure 15 MIDs is shown in accordance with some example embodiments of the present disclosure. Except for the DC link topology, Figure 17 , the configuration of Figure 7 is similar to the configuration of . Therefore, the description of similar features will be omitted here for brevity.

[0133] The third port of the first MID Ml is coupled to the fifth port of the second MID M2, the third port of the first MID M2 is coupled to the fifth port of the second MID M4, the third port of the first MID M4 is coupled to the fifth port of the second MID M3, and the third port of the first MID M3 is coupled to the fifth port of the second MID Ml. Thus, the third and fifth ports of the first, second, and third MIDs Ml -M3 form a ring topology, rather than coupling all three MIDs to a common node in Figure 7

[0134] By forming a DC link between every two MIDs of the power grid system, the delivery of DC current between the MIDs will be more flexible and easier to implement.

[0135] Figure 18 A block diagram of a power grid system of four Figure 15 MIDs according to some example embodiments of the present disclosure is shown. In addition to the DC link topology, Figure 18 the configuration is similar to that of Figure 8 . Thus, for the sake of brevity, descriptions of similar features will be omitted here.

[0136] The third port of the first MID Ml is coupled to the fifth port of the second MID M2, the third port of the first MID M2 is coupled to the fifth port of the second MID M4, the third port of the first MID M4 is coupled to the fifth port of the second MID M3, and the third port of the first MID M3 is coupled to the fifth port of the second MID Ml. Thus, the third and fifth ports of the first, second, and third MIDs Ml -M3 form a ring topology, rather than coupling all three MIDs to a common node in Figure 8

[0137] Similarly, by forming a DC link between every two adjacent MIDs of the power grid system, the delivery of DC current between the MIDs will be more flexible and easier to implement.

[0138] Further, while operations are depicted in a particular order, this should not be understood as requiring performance of such operations in the particular order shown or in any other order, nor requiring performance of all illustrated operations to implement the desired result. In certain circumstances, multitasking and parallel processing can be advantageous. Likewise, while a number of specific implementation details are contained in the above discussion, these should not be construed as limiting the scope of the disclosure, but merely as describing features that can be specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination.

[0139] ​​Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A modular interconnection device (10), comprising: a modular port assembly (20) configured to deliver alternating current (AC) and / or direct current (DC); a node (NO) coupled to an AC source via a first switch (12) and the modular port assembly (20), the first switch (12) configured to selectively disconnect the modular interconnection device (10) from the AC source; a converter (16) coupled to the node (NO) via a second switch (13) and to a DC source via a third switch (15), the converter (16) configured to convert AC current to DC current or DC current to AC current; a local controller (18) coupled to the first, second, and third switches and configured to control operation of the first, second, and third switches, wherein the modular port assembly (20) comprises: a first port (21) coupled to the first switch (12) and configured to receive AC current from or deliver AC current to the AC source; a second port (22) coupled to the node (NO) directly or via a fourth switch (14) and configured to selectively deliver AC current between modular interconnection devices; a third port (23) coupled to the third switch (15) and configured to selectively deliver DC current between modular interconnection devices; and a fourth port (24) coupled to the node (NO) and configured to deliver AC current between modular interconnection devices.

2. The modular interconnection device (10) of claim 1, wherein the modular interconnection device (10) is configured to be coupled to another modular interconnection device and to deliver power to or receive power from the other modular interconnection device; and the local controller (18) of the modular interconnection device (10) is configured to communicate with a local controller of the other modular interconnection device or a control center of a power supply network.

3. The modular interconnect device (10) of claim 1, wherein, the first switch (12) is coupled between the modular port assembly (20) and the node (NO).

4. The modular interconnection device (10) of claim 3, wherein the node (NO) is further coupled to the modular port assembly (20) via the fourth switch (14) or directly; and the local controller (18) is further coupled to the fourth switch (14) and configured to control operation of the fourth switch (14).

5. The modular interconnection device (10) of claim 4, further comprising a fifth switch (SO) coupled to a cable and the local controller (18) and configured to selectively disconnect the cable from the DC source.

6. The modular interconnect device (10) of claim 1, wherein, The local controller (18) is integrated in the converter (16).

7. The modular interconnect device (10) of claim 1, wherein, The local controller (18) is further configured to turn off the first switch (12) in response to receiving information indicating a failure of the AC source.

8. The modular interconnect device (10) of claim 1, wherein, The local controller (18) is further configured to turn off the second switch (13) in response to receiving information indicating a failure of the converter (16).

9. The modular interconnect device (10) of claim 1, wherein, The local controller (18) is further configured to turn on the third switch (15) in response to receiving a request to deliver DC current from the modular interconnect apparatus (10) to another modular interconnect apparatus or receiving a request to receive DC current from the other modular interconnect apparatus to the modular interconnect apparatus (10).

10. The modular interconnect device (10) of claim 1, wherein, The local controller (18) is further configured to turn on the fourth switch (14) in response to receiving a request to deliver AC current from another AC source or another converter.

11. The modular interconnect device (10) of claim 1, wherein, The local controller (18) is further configured to turn on the fourth switch (14) and turn off the first switch (12) in response to receiving a request to convert reactive AC current from another AC source.

12. The modular interconnect apparatus (10) of claim 1, further comprising: a fifth switch (17) coupled to the converter (16) and configured to disconnect the converter from a DC source; and wherein the modular port assembly (20) includes a fifth port (25) coupled to the fifth switch (17) and configured to deliver DC current between modular interconnect apparatuses, the local controller (18) is further coupled to the fifth switch (17) and configured to control operation of the fifth switch (17).

13. The modular interconnect device (10) of claim 11, wherein, The local controller (18) is further configured to turn on the fifth switch (17) in response to receiving a request to receive DC current from another modular interconnect apparatus or a request to deliver DC current to another modular interconnect apparatus.

14. The modular interconnect device (10) of claim 1, wherein, The local controller (18) is further configured to control the converter (16) to receive or deliver DC current based on a load redistribution request.

15. A power grid system, the power grid system comprising: a first modular interconnect apparatus according to any of claims 1 to 14; a second modular interconnect apparatus according to any of claims 1 to 14, the second modular interconnect apparatus selectively coupled to the first modular interconnect apparatus and configured to deliver power between the first modular interconnect apparatus and the second modular interconnect apparatus.

16. The power grid system of claim 15, wherein, a second port of the first modular interconnect apparatus selectively coupled to a fourth port of the second modular interconnect apparatus.

17. The power grid system of claim 16, wherein, a third port of the first modular interconnect apparatus selectively coupled to a third port of the second modular interconnect apparatus.

18. The power grid system of claim 15, further comprising a third modular interconnect device according to any of claims 1 to 14, the second and fourth ports of the first, second and third modular interconnect devices being coupled in a ring topology.

19. The power grid system of claim 18, wherein, the third ports of the first, second and third modular interconnect devices being coupled to a common node (Nl).

20. The power grid system of claim 18, wherein, the third and fifth ports of the first modular interconnect device according to claim 10, the second modular interconnect device according to claim 9 and the third modular interconnect device according to claim 10 being coupled in a ring topology.

21. The power grid system of claim 15, further comprising an energy storage device coupled with the third port of the first or second modular interconnect device.

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