Off-grid power distribution system
By introducing sockets with residual current devices (RCDs) and main circuit breakers working together in off-grid equipment, the problem of current interruption when the leakage point is located downstream is solved, thus improving the electrical safety of the equipment.
Patent Information
- Application Number
- CN202510890401.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-07-25
- Filing Date
- 2025-06-30
- Publication Date
- 2026-01-30
AI Technical Summary
In existing technologies, when off-grid devices such as trailer cars have a leakage point located downstream of the main circuit breaker, the current cannot be effectively cut off, leading to safety issues.
By introducing sockets with residual current devices (RCDs) into the power distribution system, and combining the main circuit breaker and the RCD working together, the current can be cut off regardless of the location of the leakage point.
It enables reliable current interruption in any leakage situation, improving the electrical safety of the equipment and preventing electric shock accidents.
Smart Images
Figure CN121440474A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a power distribution system that supplies power from a home power source, independent of the power grid, to power-consuming load devices (electrical equipment). Background Technology
[0002] Patent Document 1 describes an example of a structure that does not use commercial power. This structure is configured to charge an energy storage unit with electricity generated by a solar power generation unit and then convert that electricity into AC power via an inverter to supply electrical products (load devices) such as air conditioning equipment and lighting equipment. Furthermore, this structure can also be a trailer house or a camping car.
[0003] Patent Document 1: Japanese Utility Model Registration No. 3230983
[0004] In trailers and similar structures that are equipped with their own solar power units and batteries, a power distribution system is typically built internally, similar to that of ordinary houses and buildings that use commercial power. For example, the output of a high-voltage cut-off switch connected to solar panels and batteries is introduced into a distribution panel, and then connected to sockets via a main circuit breaker and its downstream circuit breakers within the distribution panel. While trailers and similar structures are designed to be electrically insulated from people moving inside, in situations such as high humidity or leaks, the resistance between people inside and the metal parts of the structure, such as the frame, decreases, increasing the likelihood of current flowing between people in contact with loads powered from sockets and the metal parts of the frame. In such cases, if a leakage point exists within the structure, and this leakage point is upstream (on the power supply side) of the main circuit breaker, a difference arises between the outgoing and returning current values from the main circuit breaker, causing the main circuit breaker to trip and interrupt the current. However, if the leakage point is downstream of the main circuit breaker (the socket side), there is no difference between the outgoing and returning current values in the main circuit breaker, therefore the current cannot be interrupted by the main circuit breaker. In other words, in off-grid structures such as caravans that are disconnected from commercial power and powered by their own electricity, conventional power distribution structures cannot completely cut off leakage or electric shock, leaving room for improvement in safety. Summary of the Invention
[0005] This invention was made in view of the above-mentioned technical problems, and its purpose is to provide a power distribution system that can reliably provide leakage current protection for off-grid devices with their own power supply.
[0006] To achieve the above objectives, the present invention is an off-grid power distribution system having a power distribution system that distributes power from a home power source independent of the commercial power source to a socket within a structure disconnected from the commercial power source, wherein the power distribution system is equipped with a main circuit breaker, and the off-grid power distribution system is characterized in that the socket is composed of a socket with a residual current device (RCD).
[0007] According to the present invention, when a leakage occurs upstream of the main circuit breaker (on the home power supply side), and the resistance of the structure decreases, causing electrical continuity between the appropriate load device connected to the socket and the structure, the main circuit breaker operates due to the current imbalance, and the current is interrupted. Conversely, when a leakage occurs downstream of the main circuit breaker (on the socket side), and electrical continuity occurs between the appropriate load device connected to the socket and the structure, although the main circuit breaker does not operate, the residual current device (RCD) in the socket operates to interrupt the current. Thus, regardless of the location of the leakage, the current can be interrupted, thereby preventing electric shock and improving the electrical safety of the building. Attached Figure Description
[0008] Figure 1 This is a circuit diagram used to illustrate one embodiment of the present invention. Detailed Implementation
[0009] Next, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the embodiments described below are merely one example of how the present invention is implemented and do not limit the scope of the invention.
[0010] exist Figure 1 The image shows an off-grid caravan (hereinafter referred to as a caravan) 1 as an example of an off-grid device or structure that does not use commercial power. The caravan 1 has rubber tires 2, thus insulated from the ground. As its own power source, it has a secondary battery 3 and solar panels 4, which are located on the exterior of the caravan 1 or configured inside as needed.
[0011] exist Figure 1 In the attached diagram, reference numeral 5 indicates a power conditioner, which includes a ZCT (zero-phase converter) 6 and a switching switch 7. A secondary battery 3 is connected to the power conditioner 5 via a DC / DC converter 8. Additionally, a solar panel 4 is connected to the power conditioner 5. The housings of the power conditioner 5 and the solar panel 4 are electrically connected to the frame 9 of the trailer 1.
[0012] The internal electrical distribution system of the towed caravan 1 is basically the same as that of conventional electrical distribution systems. The output from the power regulator 5 is supplied via a distribution panel 10 to power-consuming loads (electrical equipment) 11 such as lighting, air conditioning, or cooking appliances. The distribution panel 10 includes a switch 12, a main circuit breaker 13, and a sub-circuit breaker 14. The switch 12 is a switch used to switch the power supply of the towed caravan 1 between the secondary battery 3 or solar panel 4 and the commercial power supply 15. The main circuit breaker 13 is a conventional residual current device (RCD) that operates based on the imbalance between the outgoing current and the returning current, thereby cutting off the circuit.
[0013] The sub-circuit breaker 14 is a conventionally known circuit breaker that operates by disengaging a current exceeding a set current to interrupt the circuit. The switch 12, main circuit breaker 13, and sub-circuit breaker 14 are connected in the order listed herein, and a socket 16 for connecting the load device 11 is connected to the sub-circuit breaker 14 via prescribed wiring. This socket 16 is a socket equipped with an Earth Leakage Circuit Breaker (ELCB) 17.
[0014] Furthermore, regarding the interconnection operation option for using commercial power supply 15, a junction box (TB) 18 for connecting to commercial power supply 15 is installed on the outer surface of the trailer 1. A service breaker (SB) 19 is provided on the aforementioned distribution panel 10, between the junction box 18 and the switch 12. A circuit is also provided connecting the output side of the service breaker 19 to the switching switch 7 in the aforementioned power regulator 5, with a cooperating circuit breaker 20 and a power generation disconnection circuit breaker 21 connected in series in this circuit. Furthermore, the cooperating circuit breaker 20 and the power generation disconnection circuit breaker 21 are located inside the distribution panel 10. Additionally, the housings of the distribution panel 10, junction box 18, etc., are electrically connected to the frame 9 of the trailer 1.
[0015] Next, the leakage current protection based on the above power distribution system will be explained. Figure 1 The reference numerals A and B show the leakage points in the wiring of the trailer caravan 1. Leakage point A is upstream of the main circuit breaker 13 (power supply side), and leakage point B is downstream of the main circuit breaker 13 (sub-circuit breaker 14 side) and upstream of the sub-circuit breaker 14 (main circuit breaker 13 side).
[0016] The living space of the trailer caravan 1 is covered by electrically insulating flooring, wall materials, etc. However, in cases of high humidity or dampness due to water spillage, the resistance between the inner surface of the living space and the frame 9 decreases. In such cases, the load device 11 leaks current, and if a person 22 comes into contact with the load device 11, a circuit is established between the load device 11 and the frame 9, and electrical conduction occurs.
[0017] In this case, if a leakage occurs at the leakage point A upstream of the main circuit breaker 13, a portion of the return current in the main circuit breaker 13 flows from the leakage point A through the frame 9, thus creating an imbalance between the outgoing and returning current values in the main circuit breaker 13. Therefore, the main circuit breaker 13 operates to disconnect the circuit. Furthermore, in this case, the leakage point A also becomes an upstream location relative to the residual current device 17 installed in the socket 16, thus creating an imbalance between the outgoing and returning current values in the residual current device 17 as well. As a result, there is also a possibility that the circuit may be disconnected through the residual current device 17. The priority order of the disconnection operations of the main circuit breaker 13 and the residual current device 17 can be appropriately determined by changing their respective setting values.
[0018] Conversely, if a leakage occurs at leakage point B between the main circuit breaker 13 and the sub-circuit breaker 14, the leakage occurs downstream of the main circuit breaker 13. Therefore, there is no imbalance between the outgoing and returning current values, and the main circuit breaker 13 will not trip. On the other hand, the leakage occurs upstream of the residual current device 17 installed in the socket 16. This causes an imbalance between the outgoing and returning current values in the residual current device 17, resulting in the residual current device 17 tripping to disconnect the circuit.
[0019] Therefore, according to the power distribution system in the above-described embodiment of the present invention, even if a leakage occurs at any part of the wiring inside the vehicle, either the main circuit breaker 13 or the leakage current cut-off device 17 of the socket 16 will operate to cut off the circuit, thereby reliably preventing or suppressing electric shock to the person 22 who is in contact with the load device 11.
[0020] Furthermore, the present invention is not limited to the above-described embodiments. In addition to towed caravans, off-grid structures or devices using the present invention can also be buildings located in arid places such as deserts or polar regions that cannot use commercial power sources, artificial satellites, lunar surface, Mars and other planetary exploration vehicles, etc.
[0021] Explanation of reference numerals in the attached figures:
[0022] 1…Caravan; 2…Tires; 3…Secondary batteries; 4…Solar panels; 5…Power regulator; 6…ZCT (Zero-phase converter); 7…Changeover switch; 8…DC / DC converter; 9…Frame; 10…Distribution panel; 11…Load equipment; 12…Switcher; 13…Main circuit breaker; 14…Sub-circuit breaker; 15…Commercial power supply; 16…Socket; 17…Residual current circuit breaker; 18…Junction box; 19…Service circuit breaker; 20…Cooperation circuit breaker; 21…Power generation disconnect circuit breaker; 22…People; A, B…Leakage points.
Claims
1. An off-grid power distribution system having a power distribution system that distributes power from a self-home power source independent of a commercial power source to a socket inside a structure that is disconnected from the commercial power source, wherein a main breaker is provided in the power distribution system, and the socket is constituted by a socket with a leakage breaker.