Electric power protection system, electric power protection method and ship

Abstract

The invention discloses an electric power protection system, an electric power protection method and a ship, and belongs to the technical field of electric power systems.The electric power protection system comprises multiple sections of power distribution boards, and bus sections on the power distribution boards are sequentially connected through cables to form a closed looped network; all the bus protection measurement and control devices, the load protection measurement and control device and the generator protection measurement and control device in the closed looped network form annular communication connection; the bus protection measurement and control device is configured to respond to the fault signal and disconnect a bus section on the same distribution board with the bus protection measurement and control device from other bus sections; the generator protection measurement and control device is configured to disconnect the connection between the corresponding generator and the bus section in response to the fault signal; and the load protection measurement and control device is configured to disconnect the connection between the corresponding load and the bus section in response to the fault signal. According to the invention, the power supply continuity, reliability and redundancy of the system are effectively improved.

Description

Technical Field

[0001] This application relates to the field of power system technology, and in particular to a power protection system, a power protection method, and a ship. Background Technology

[0002] With the development of the maritime power strategy, marine engineering vessels are becoming larger, and their operating conditions are becoming increasingly complex. Dynamic positioning requirements are constantly rising, and traditional power systems are struggling to meet the demands for reliability, flexibility, and economy. Closed-loop power systems can achieve energy distribution and redundant power supply among multiple power sources. When faults occur at generation, distribution, or feeding points, power can be quickly supplied through other paths, reducing power outage time and impact. However, with the increasing application of closed-loop systems, relay protection issues are becoming increasingly important. Unlike traditional radial networks, determining current flow direction and fault location is more difficult, and coordinating protection devices is more challenging. Summary of the Invention

[0003] This invention provides a power protection system, a power protection method, and a vessel. By collecting current and phase signals, the fault location is determined. Various protection and control devices form a redundant communication ring network to exchange status signals and fault information. Directional protection enables rapid fault location and isolation.

[0004] To achieve the above objectives, in a first aspect, this application provides a power protection system, comprising: The distribution board has multiple sections, each of which is equipped with a busbar section, at least one busbar protection and control device, at least one load protection and control device, and at least one generator protection and control device. The busbar sections on each distribution board are connected sequentially by cables to form a closed loop network. All the busbar protection and control devices, the load protection and control devices, and the generator protection and control devices within the closed loop network form a ring communication connection. The bus protection and control device is configured to disconnect the bus segment on the same switchboard as the bus protection and control device from other bus segments in response to a fault signal. The generator protection and control device is configured to disconnect the corresponding generator from the bus section in response to a fault signal. The load protection and control device is configured to disconnect the corresponding load from the bus section in response to a fault signal.

[0005] In some embodiments, the system further includes a switch, and the closed loop network includes at least one of the switches, which are communicatively connected to the bus protection and control device, the load protection and control device, and the generator protection and control device.

[0006] In some embodiments, each busbar segment is provided with a switch, which is communicatively connected to all the busbar protection and control devices, load protection and control devices and generator protection and control devices on the busbar segment.

[0007] In some embodiments, the busbar protection and control device includes a busbar control unit, a busbar detection unit, and busbar switches disposed at both ends of the busbar section on the same switchboard as the busbar protection and control device; wherein... The bus detection unit is configured to detect the voltage and current signals at both ends of the bus segment and transmit the collected detection results to the bus control unit. The bus control unit is configured to control the bus switch based on a comparison between the detection result and the setting value.

[0008] In some embodiments, the generator protection and control device includes a generator control unit, a generator signal acquisition unit, a generator detection unit, and a generator feeder switch; wherein, The generator feeder switch is connected between the bus section and the generator; The generator detection unit is configured to detect voltage and current signals at the generator feeder. The generator signal acquisition unit is configured to acquire the detection results of the generator detection unit and the detection results from the generator side; and transmit the acquired detection results to the generator control unit; The generator control unit is configured to control the generator feeder switch based on a comparison between the detection result and the set value.

[0009] In some embodiments, the load protection and control device includes a load control unit, a load detection unit, and a load feeder switch; wherein, The load feeder switch is connected between the bus section and the load; The load detection unit is configured to detect the current signal at the load feeder and transmit the collected detection results to the load control unit. The load control unit is configured to control the load feeder switch based on a comparison between the detection result and the set value.

[0010] In some embodiments, the bus protection monitoring and control device, the load protection monitoring and control device, and the generator protection monitoring and control device all include a display screen.

[0011] Secondly, this application also provides a power protection method, applied to the power protection system described above, including, First-stage protection: In the event of a fault in the generator, load, busbar, or inter-busbar cable, determine the location of the fault and disconnect the switch at the location of the fault. Second-stage protection: If the switch at the fault location fails to operate, determine the location of the fault on the busbar and disconnect the busbar switch of the faulty busbar segment.

[0012] In some embodiments, the fault includes at least one of a feeder short-circuit fault, a ground fault, and a phase imbalance fault.

[0013] In some embodiments, in the event of the short-circuit fault or the ground fault, a third stage of protection is also included: if the switches at both ends of the bus segment where the fault occurs fail to operate, all bus switches in the closed loop network are disconnected.

[0014] In some embodiments, disconnecting all bus switches within the closed loop network includes disconnecting all generator sets on the bus segment where the fault occurs from the bus segment.

[0015] In some embodiments, the method for determining the fault location includes: When the current signal detected by the generator protection and control device is abnormal, the current collected by the generator protection and control device exceeds the set value, the current collected by the current transformer on the generator side is opposite to the current detected by the current transformer in the generator detection unit, or the fault current direction is pointing towards the generator set, and the fault location is at the generator. When the load protection and control device detects an abnormal current signal, the current collected by the load protection and control device exceeds the set value, the fault current direction points to the load, and the fault location is at the load feeder. When the current signal detected by the bus protection and control devices at both ends of the bus section is abnormal, the current collected by the bus protection and control devices exceeds the set value, the direction of the fault current detected at both ends of the bus section points to the bus section, and the fault location is the bus between the two bus protection and control devices. If the bus protection and control device at both ends of the cable detects an abnormal current signal, the current collected by the bus protection and control device exceeds the set value, the current direction of the current transformers configured on both sides of the cable is opposite, or the fault current detected on both sides of the cable points to the cable, and the fault location is the cable.

[0016] Thirdly, this application provides a ship that includes the aforementioned electrical protection system.

[0017] When a fault occurs in the power system, the protection and control device of this application quickly isolates the fault, restoring power supply to the non-faulty areas, greatly reducing the scope and duration of power outages, and improving power supply continuity and reliability. This application designs a multi-layered backup protection method, including differential protection, directional protection, non-directional protection, and residual voltage protection, to prevent hidden faults from affecting the power system and improve system reliability and redundancy. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 A topology diagram of a ship's electrical protection system provided in this application embodiment; Figure 2 A single-line diagram of a ship's electrical protection system provided in the embodiments of this application; Figure 3 This is a schematic diagram of the connection of the ship's electrical protection system provided in the embodiments of this application; Figure 4 A flowchart of a ship electrical protection method provided in an embodiment of this application; Figure 5 A short-circuit protection logic diagram provided for embodiments of this application; Figure 6 The grounding protection logic diagram provided for the embodiments of this application; Figure 7 This is a phase imbalance protection logic diagram provided for an embodiment of this application. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] Furthermore, descriptions involving "first," "second," etc., in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0022] When a short circuit occurs at a section of the closed-loop busbar, conventional selective protection cannot accurately identify the source of the inrush current on the left or right side of the fault point. It is necessary to combine current power direction information to achieve directional selective protection. Short circuit point identification, identification of grounding faults, hidden faults and mechanical faults, coordination of multi-layer protection time sequences and independent protection are the challenges of directional selective protection for medium-voltage AC ring networks in ships.

[0023] To address the aforementioned problems, embodiments of this application provide a shipboard electrical protection system, including: The system consists of multiple distribution boards, with busbar sections installed on the boards. The busbar sections on the distribution boards are connected sequentially by cables to form a closed loop network. Each distribution board is equipped with a busbar protection and control device, at least one load protection and control device, and at least one generator protection and control device. All busbar protection and control devices, load protection and control devices, and generator protection and control devices form a ring communication connection. The bus protection and control device is configured to disconnect the connection between the local switchboard and other switchboards in response to a fault signal. The generator protection and control device is configured to disconnect the connection between the generator protection and control device and its corresponding generator in response to a fault signal; The load protection and control device is configured to disconnect the connection between the load protection and control device and its corresponding load in response to a fault signal.

[0024] In this closed-loop network, all bus protection and control devices, load protection and control devices, and generator protection and control devices are connected via Ethernet to form a redundant ring network to achieve IEC61850 communication and exchange information such as voltage signals, current signals, and fault signals in the power system.

[0025] In some embodiments, the busbar protection and control device includes a busbar control unit, a busbar detection unit, and a busbar switch. The busbar detection unit detects the voltage and current signals at both ends of the busbar segment and transmits the detected results to the busbar control unit. In this embodiment, the busbar detection unit includes a current transformer and a voltage transformer. The current transformer is located at both ends of the busbar segment and connected in series with the busbar segment to detect the current signals at both ends of the busbar segment. The voltage transformer detects the voltage signals of the busbar segment.

[0026] The bus control unit processes the detection results and controls the corresponding bus switches; the bus switches are respectively located at both ends of the bus section and are connected between the bus and the cable.

[0027] In some embodiments, the generator protection and control device includes a generator control unit, a generator signal acquisition unit, a generator detection unit, and a generator feeder switch; wherein, the generator feeder switch is connected between the bus and the generator; the generator detection unit detects the voltage and current signals at the generator feeder; the generator detection unit includes a current transformer and a voltage transformer, wherein the current transformer is connected in series between the generator feeder switch and the bus, and is used to detect the current signal flowing from the generator into the bus. The voltage transformer in the generator protection and control device is used to detect the voltage signal at the generator feeder. The generator signal acquisition unit acquires the detection results from the generator detection unit and the detection results from the generator side; and transmits the acquired detection results to the generator control unit; the generator control unit processes the detection results and controls the corresponding generator feeder switch.

[0028] In some embodiments, the load protection and control device includes a load control unit, a load detection unit, and a load feeder switch; wherein, the load feeder switch is connected between the bus and the load; the load detection unit detects the current signal at the load feeder and transmits the collected detection results to the load control unit; the load detection unit includes a current transformer connected in series between the bus and the load feeder switch, for monitoring the current signal flowing from the bus into the load; the load control unit processes the detection results and controls the load feeder switch.

[0029] The bus protection and control device, generator protection and control device, and load protection and control device all include a communication unit for communication. The communication unit is used to transmit data and signals from the detection unit and control unit to other devices or host computer for signal exchange such as switch status and fault conditions.

[0030] In some embodiments, the system further includes a switch, and the ring network includes at least one of the switches. The switch is communicatively connected to the communication units of the bus protection and control device, the load protection and control device, and the generator protection and control device. The communication connection method is IEC61850 communication.

[0031] In some embodiments, an upper-level switch is also included. Each busbar segment is equipped with a switch. The switch on each busbar segment is communicatively connected to all the busbar protection and control devices, load protection and control devices, and generator protection and control devices on the busbar segment. The upper-level switch is connected to the switch on each busbar segment to enable signal interaction between the protection devices on multiple busbar segments.

[0032] In some embodiments, the bus switch, generator feeder switch, and load feeder switch may be circuit breakers.

[0033] Figure 1 This is a topology diagram of a ship's electrical protection system provided in an embodiment of this application. Figure 2 A single-line diagram of the ship's electrical protection system provided in the embodiments of this application is shown below. Figures 1-2 As shown, the system includes three distribution boards, each with a busbar segment. Adjacent busbar segments are connected sequentially via busbar switches, cables, and another busbar switch. The busbar segments on the distribution boards are also connected sequentially via cables, forming a closed loop network. Each distribution board has two sets of busbar protection and control devices, one load protection and control device, and two sets of generator protection and control devices. Each distribution board also has a switch, which forms a communication loop with the busbar protection and control devices, load protection and control devices, and generator protection and control devices on its respective distribution board. The switch on each distribution board communicates with a host computer, which can be an energy management system, etc. The entire closed loop network includes a top-level switch, and the switch corresponding to each distribution board communicates with this top-level switch using IEC61850 communication, enabling communication signal exchange among multiple busbar segments.

[0034] Figure 3 This is a schematic diagram of the connection of the ship's electrical protection system provided in the embodiments of this application, such as... Figure 3As shown, the generator protection and control device includes a generator control module and a generator feeder switch, which can operate independently. The generator control module includes a generator control unit, a generator signal acquisition unit, and a generator detection unit. The bus protection and control device includes a bus control module and a bus switch, which can operate independently. The bus control module includes a bus control unit and a bus detection unit. The load protection and control device includes a load control module and a load feeder switch, which can operate independently. The load control module includes a load control unit and a load detection unit. In the figure, six generators are connected to the generator feeder switch via power lines. The generator control module monitors the current, voltage, and phase signals inside the generator and at the feeder, and protects the generator, controlling the generator feeder switch to open or close. The load control module monitors and protects the load-side current and phase signals, controlling the load feeder switch to open or close. The bus control module monitors and protects the current, voltage, and phase signals on and between the busbars, controlling the bus switch to open or close. The generator monitoring and control module, load monitoring and control module, bus monitoring and control module and switch form a ring IEC61850 communication connection to exchange signals and realize fault location and protection.

[0035] In some embodiments, the bus protection monitoring and control device, the load protection monitoring and control device, and the generator protection monitoring and control device all include a display screen, which can display various monitoring data.

[0036] This application also provides a method for electrical protection in a ship, employing the aforementioned ship electrical protection system, such as... Figure 4 As shown, including, First-stage protection: In the event of a fault in the generator, load, busbar, or inter-busbar cable, determine the location of the fault and disconnect the switch at the location of the fault. Second-stage protection: If the switch at the fault location fails to operate, determine the location of the fault on the bus and disconnect the switches at both ends of the bus where the fault is located.

[0037] In some embodiments, the faults include short-circuit faults, ground faults, and phase imbalance faults.

[0038] In some embodiments, in the event of a short-circuit fault or a ground fault, a third stage of protection is also included: if the switches at both ends of the busbar where the fault occurs fail to operate, the busbar switches in all the busbar protection and control devices within the ring network are disconnected.

[0039] The faults include at least one of the following: short circuit faults, grounding faults, and phase imbalance faults at the generator side, bus section, inter-bus section connecting cable, and load feeder; as well as hidden faults, including protection device faults, input signal faults, protection device output faults, switch mechanical faults, and communication faults.

[0040] Specifically, the generator short-circuit fault protection function is divided into differential protection, directional protection and non-directional protection; the generator ground fault protection function is divided into directional protection, non-directional protection and residual voltage protection; the generator phase imbalance fault protection is negative sequence inverse time protection.

[0041] Busbar short-circuit fault protection functions are divided into differential protection, directional protection and non-directional protection; busbar grounding fault protection functions are divided into directional protection, non-directional protection and residual voltage protection; busbar phase imbalance fault protection includes negative sequence inverse time protection.

[0042] The inter-busbar cable short-circuit fault protection function is divided into differential protection, directional protection and non-directional protection; the inter-busbar cable grounding fault protection function is divided into directional protection, non-directional protection and residual voltage protection; the inter-busbar cable phase imbalance fault protection includes negative sequence inverse time protection.

[0043] The load short-circuit fault protection function is divided into directional protection and non-directional protection; the load ground fault protection function is divided into directional protection and non-directional protection; the load phase imbalance fault protection includes negative sequence inverse time protection.

[0044] In some embodiments, the method for determining the location of a fault includes: If the current signal detected by the generator protection and control device is abnormal, including if the current collected by the generator protection and control device exceeds the set value, and according to the phase judgment, the current collected by the current transformer on the generator side is opposite to the current detected by the current transformer in the generator detection unit, or the fault current direction is pointing towards the generator set, then the fault location is at the generator. If the load protection and control device detects an abnormal current signal, including if the current detected by the load protection and control device exceeds the set value, and the fault current direction is pointed towards the load according to the phase judgment, then the fault location is at the load feeder. When the current signal detected by the bus protection and control devices at both ends of the bus section is abnormal, including when the current detected by the bus protection and control devices exceeds the set value, and the fault current detected at both ends of the bus section points to the bus section according to the phase judgment, the fault location is the bus section between the two bus protection and control devices. When the bus protection and control devices at both ends of the cable detect abnormal current signals, including when the collected current exceeds the set value and, based on phase judgment, the current directions of the current transformers configured on both sides of the cable are opposite, or when the fault current detected on both sides of the cable points to the cable, the fault location is the cable.

[0045] like Figure 5 As shown, specifically, when a short circuit fault occurs at the generator feeder, the first stage of protection is differential protection. Each generator signal acquisition unit acquires the current signal detected by the current transformer on the corresponding generator side and the current signal detected by the corresponding generator detection unit. The generator control unit processes the two sets of current signals received. If the vector sum of the two sets of current signals is not zero, the generator control unit controls the generator feeder switch to open. If the corresponding generator feeder switch fails to operate at this time, meaning it remains closed, it indicates the fault still exists, suggesting a hidden fault. This triggers the second stage of protection, which is bus directional protection. The current transformers at both ends of the current distribution board detect the current value and phase of this node. The bus detection unit inputs the detected current value and phase to the bus control unit for processing. If the current collected by the current transformers at both ends of the current distribution board exceeds the set value, and the current direction, based on the phase, points towards the faulty generator set, the bus switches on both sides of the distribution board open at time T1, and the generator feeder switches of all generator sets on the current distribution board open at time T3. Here, the set value is the first set value, which is 1.5 to 1.8 times the rated current value of the bus switch. If the bus switch fails to operate at this time, it indicates a hidden fault, triggering the third level of protection. The third layer of protection is non-directional. If the current value collected by the bus detection units on both sides of the distribution board exceeds the set value, all bus switches in the ring network will non-directionally disconnect at T2 seconds. The generator feeder switches of the faulty generator sets will disconnect, while the generator feeder switches of the remaining generator sets will close and operate normally. The set value here is the second set value, which is 1.2 to 1.5 times the rated current value of the bus switch. The set value can also be precisely checked and corrected based on the selective analysis simulation calculation results of the actual system.

[0046] When a short-circuit fault occurs on the busbar, the first stage of protection is initiated. This first stage is differential protection. The busbar protection and control device on each distribution board detects the current in the current transformers at the busbar inlet and feeder on that distribution board. If the vector sum of these currents exceeds a limit, the busbar switches at both ends of the current distribution board busbar immediately disconnect. All generator feeder switches on the current distribution board busbar disconnect non-directionally at T3 seconds. This limit is determined through short-circuit current calculation. The current transformer current at the busbar inlet and feeder represents the current value flowing into the busbar detected by the generator protection and control device of each generator set on the busbar section, and the current value flowing into the load detected by the load protection and control device. Specifically, the generator protection and control device and the load protection and control device transmit the detected currents together to the busbar protection and control device for vector calculation and comparison. If, at this time, the corresponding busbar switch and generator feeder switch fail to operate, and the fault still exists (e.g., the short-circuit current in the busbar still exists), then a hidden fault is identified, and the second stage of protection is initiated. The second stage is for directional bus protection. The bus protection monitoring and control device on the distribution board connected to the current distribution board collects the current and phase of the current transformer at the connection point with the current distribution board. If the collected current exceeds the set value and the current direction points towards the current distribution board, the two bus switches connected to the bus switches on the current distribution board will disconnect at time T1. The generator feeder switches of all generator sets on the current distribution board will disconnect non-directionally at time T3. Here, the set value is the first set value, which is 1.5 to 1.8 times the rated current value of the bus switch. If any of the switches to be disconnected in the second stage fails to operate and the fault still exists, it is determined that there is a hidden fault, and the third layer of protection is entered. The third layer of protection is non-directional. The bus protection monitoring and control device on the current distribution board connected to the current distribution board collects the current from the current transformer at the connection point. If the collected current exceeds the set value (here, the set value is the second set value, which is 1.2 to 1.5 times the rated current of the bus switch), then all bus switches in the ring network will non-directionally disconnect at time T2, and all generator feeder switches on the faulty bus section will non-directionally disconnect at time T3. To prevent short circuits in the faulty bus section from causing malfunctions in other bus switches, a circuit breaker interlocking function must be implemented.

[0047] When a short-circuit fault occurs in the cable between distribution boards, the first stage of protection is differential protection. It detects the current in the current transformers within the bus protection control devices on both sides of the cable. If the differential current vector sum of the two detected currents is not zero, the bus switches on both sides of the cable immediately disconnect. If the switches fail to operate and the fault persists, a hidden fault is identified, and the second layer of protection is initiated. The second layer of protection is cable directional protection. The current transformers within the bus protection control devices on both sides of the cable collect the current and phase data. If the collected current exceeds the set value and the current direction points towards the cable connecting the distribution boards, the bus switches at both ends of the cable between the distribution boards disconnect at time T1. Here, the set value is the first set value, which is 1.5 to 1.8 times the rated current of the bus switch. If the bus switch fails to operate at this time, a hidden fault is identified, and the third layer of protection is initiated. The third layer of protection is non-directional protection. The current transformers in the bus protection monitoring and control devices at the distribution boards on both sides of the cable collect the current transformer current. If the collected current exceeds the setting value, all bus switches in the ring network will be non-directionally disconnected at T2 seconds. The setting value here is the second setting value, which is 1.2 to 1.5 times the rated current value of the bus switch.

[0048] When a short-circuit fault occurs at the load feeder connected to the busbar, the first stage of protection is directional protection. The load protection monitoring and control device collects the feeder current. If the collected current exceeds the set value, the load feeder switch opens at T4 seconds and the busbar switch on the distribution board where the load is located is locked. This keeps the busbar switch closed and prevents erroneous opening. The set value here is the third set value, which is more than 1.8 times the rated current value of the load feeder switch. If the load feeder switch fails to operate and the fault still exists, it is determined that there is a hidden fault, and the second stage of protection is initiated. The second stage of protection is busbar directional protection. After T4 seconds, the busbar switch lockout is canceled via pulse. The bus protection and control devices on both sides of the busbar section where the load is located detect the current and phase of the current transformers on both sides of the busbar section. If the current value at the busbar switches on both sides of the busbar section exceeds the set value, the directional protection of the busbar switches at both ends of the busbar section where the load is located will immediately disconnect, and all generator feeder switches on that busbar section will disconnect non-directionally at T3 seconds. Here, the set value is the first set value, which is 1.5 to 1.8 times the rated current value of the busbar switch. If a hidden fault is detected, the third stage of protection will be entered. The third stage of protection is non-directional protection. The bus protection and control devices on both sides of the busbar section where the load is located detect the current of the current transformers at the busbar switches on both sides of the busbar section. If the current transformer current exceeds the set value, all busbar switches in the ring network will disconnect non-directionally at T2 seconds, and all generator feeder switches on that busbar section will disconnect non-directionally at T3 seconds. Here, the set value is the second set value, which is 1.2 to 1.5 times the rated current value of the busbar switch.

[0049] The generator, busbar section, inter-busbar cable, load-side short-circuit fault protection, and hidden fault protection are configured with multi-layered main and backup protection, enabling fault clearing within 1 second at the latest. T1 <T4<T2<T3≤1s。

[0050] like Figure 6As shown, when a ground fault occurs at the generator feeder, the first stage of protection is generator directional protection. Each generator signal acquisition unit collects the generator leakage current transformer signal and detects the zero-sequence current. If the collected current value exceeds the set current value, the corresponding generator feeder switch is directionally disconnected within T5 seconds, and the generator is de-energized. The set value here is the fourth set value, which is 1.3-1.5 times the rated current value of the generator feeder switch. If the switch fails to operate and the fault still exists, it is determined that there is a hidden fault, and the second stage of protection is initiated. The second stage of protection is bus directional protection. The current transformers at both ends of the current distribution board collect the leakage current transformer signal and detect the zero-sequence current. If the collected current exceeds the set value, the bus switches on both sides of the distribution board are directionally disconnected within T6 seconds. The set value here is the fifth set value, which is 1.2-1.3 times the rated current value of the bus switch. The voltage transformer signal acquired by the generator signal acquisition unit is detected at this time. If the acquired voltage value exceeds the set value, the generator feeder switch connected to the faulty generator will trip the ROV residual voltage protection at T8 seconds. The set value here is the sixth set value, which is below 90% of the generator's rated voltage. In this embodiment, it is preferably 50%-90% of the generator's rated voltage. If the bus switches on both sides of the distribution board fail to operate and the fault still exists, it is determined that there is a hidden fault, and the third stage of non-directional protection is entered. The current transformers at both ends of the current distribution board acquire the leakage current transformer signal. If the acquired current exceeds the set value, all bus switches in the ring network will be non-directionally disconnected at T7 seconds. The set value here is the seventh set value, which is 1.1-1.2 times the rated current value of the bus switch. The voltage inductance signal collected by the generator protection and control device corresponding to the faulty generator is detected. If the collected voltage value exceeds the set value, the ROV residual voltage protection of the generator feeder switch connected to the faulty generator will trip at T8 seconds. The set value here is the eighth set value, which is below 90% of the generator's rated voltage. In this embodiment, it is preferably 50%-90% of the generator's rated voltage.

[0051] When a ground fault occurs on a busbar section, the first stage of protection is initiated. This first stage is directional protection for the busbar. The busbar detection units on both sides of the busbar section collect signals from the current transformers. If the collected current exceeds the set value, the busbar switches on both sides of the busbar section will directionally disconnect at T6 seconds. The set value here is the fifth set value, which is 1.2-1.3 times the rated current value of the busbar switch. All generator protection and control devices on the currently faulty busbar section collect signals from the voltage transformers. If the collected voltage exceeds the set value, all generator feeder switches on the currently faulty busbar section will trip the ROV residual voltage protection at T8 seconds. The set value here is the sixth set value, which is below 90% of the generator's rated voltage. In this embodiment, it is preferably 50%-90% of the generator's rated voltage. If the busbar switches on both sides of the busbar section fail to operate and the fault still exists, it is determined that there is a hidden fault, and the second stage of protection is initiated. The second stage of protection is non-directional. The bus protection and control devices on both sides of the bus section collect signals from the current transformers and detect the zero-sequence current. If the collected current exceeds the set value, all bus switches in the ring network will non-directionally disconnect at T7 seconds. The set value here is the seventh set value, which is 1.1-1.2 times the rated current value of the bus switch. All generator signal acquisition units on the currently faulty bus section collect signals from the voltage transformers. If the acquired voltage exceeds the set value, all generator feeder switches on the currently faulty bus section will trip the ROV residual voltage protection within T8 seconds. The set value here is the eighth set value, which is below 90% of the generator's rated voltage. In this embodiment, it is preferably 50%-90% of the generator's rated voltage. If all bus switches in the ring network fail to operate and the fault still exists, it is determined that there is a hidden fault, and the third stage of protection is entered. The third stage of protection is the busbar residual voltage protection. The busbar protection and control devices on both sides of the busbar section collect the voltage transformer signal. If the collected voltage exceeds the set value, all busbar switches in the ring network will trip the ROV residual voltage protection at T8 seconds. All generator feeder switches on the faulty busbar section will trip the ROV residual voltage protection at T8 seconds. The set value here is the sixth set value, which is below 90% of the generator's rated voltage. In this embodiment, it is preferably 50%-90% of the generator's rated voltage.

[0052] When a grounding fault occurs in the cable between busbar sections, the first stage of protection is initiated. This first stage is directional cable protection. The busbar protection and control devices on both sides of the connecting cable between busbar sections collect current transformer signals. If the collected current exceeds the set value, the busbar switches on both sides of the connecting cable will directionally disconnect at T6 seconds. The set value here is the fifth set value, which is 1.2-1.3 times the rated current of the busbar switch. If the busbar switches on both sides of the connecting cable fail to operate and the fault still exists, it is determined that there is a hidden fault, and the second stage of protection is initiated. The second stage of protection is non-directional protection. The busbar detection units on both sides of the connecting cable collect current transformer signals. If the collected current exceeds the set value, all busbar switches in the ring network will non-directionally disconnect at T7 seconds. The set value here is the seventh set value, which is 1.1-1.2 times the rated current of the busbar switch. If all busbar switches in the ring network fail to operate and the fault still exists, it is determined that there is a hidden fault, and the third stage of protection is initiated. The third stage of protection is bus residual voltage protection. The bus detection unit at both ends of the faulty cable collects the voltage transformer signal. If the collected voltage exceeds the set value, all bus switches in the ring network will trip the ROV residual voltage protection at T8 seconds. The set value here is the sixth set value, which is below 90% of the generator's rated voltage. In this embodiment, it is preferably 50%-90% of the generator's rated voltage.

[0053] When a ground fault occurs on the load feeder, the first stage of protection is activated. This first stage is load directional protection. The load protection monitoring and control device corresponding to the faulty load collects the leakage current transformer signal. If the collected current exceeds the set value, the load feeder switch corresponding to the faulty load will directionally disconnect at T5 seconds. This set value is the fourth set value, which is 1.3-1.5 times the rated current value of the generator feeder switch. If the load feeder switch fails to operate and the fault still exists, it is determined that there is a hidden fault, and the second stage of protection is activated. The second stage of protection is bus directional protection. After the load-side directional protection disconnection time has expired, the bus switch lockout is canceled via pulse. The bus detection units on both sides of the bus section where the faulty load is located collect the current transformer signal. If the collected current exceeds the set value, the bus switches at both ends of that bus section will directionally disconnect at T6 seconds. This set value is the fifth set value, which is 1.2-1.3 times the rated current value of the bus switch. All generator signal acquisition units on this busbar segment acquire voltage transformer signals. If the acquired voltage exceeds the set value, the generator feeder switch trips the ROV residual voltage protection at T8 seconds. The set value here is the sixth set value, which is below 90% of the generator's rated voltage. In this embodiment, it is preferably 50%-90% of the generator's rated voltage. If a hidden fault is detected, the third stage of protection is entered. The third stage of protection is non-directional protection. The busbar detection units at both ends of the faulty busbar segment acquire current transformer signals. If the acquired current exceeds the set value, all busbar switches in the ring network disconnect non-directionally at T7 seconds. The set value here is the seventh set value, which is 1.1-1.2 times the rated current value of the busbar switch. All generator protection and control devices on the bus section with faulty load collect voltage transformer signals. If the collected voltage exceeds the set value, the generator feeder switch trips the ROV residual voltage protection at T8 seconds. The set value here is the sixth set value, which is below 90% of the generator's rated voltage. In this embodiment, it is preferably 50%-90% of the generator's rated voltage.

[0054] The generator, busbar section, cable between busbar sections, load-side grounding fault protection, and hidden fault protection are configured with multi-layer protection of main and backup protection, which can clear faults within 2 seconds at the latest. T5 <T6<T7<T8≤2s。

[0055] like Figure 7As shown, when a phase imbalance fault occurs on the generator side, the first stage of protection is initiated. This first stage is generator negative sequence inverse time protection. The generator protection and control device detects a negative sequence overcurrent and triggers the negative sequence inverse time protection, causing the generator feeder switch to open. Based on the time and current values, if the generator feeder switch has not opened by the required time, the second stage of protection is initiated. In this stage, the corresponding table of negative sequence current and opening time is used to determine whether the generator feeder switch has reached the required opening time but has not opened. The second stage of protection is negative sequence inverse time protection at the bus section. The bus protection and control device at both ends of the bus section detects a negative sequence overcurrent and triggers the negative sequence inverse time protection, causing the bus switches at both ends of the bus section to open.

[0056] When a phase imbalance fault occurs in a bus section, the first stage of protection is activated. The first stage of protection is negative sequence inverse time protection at the bus section. The bus protection and control devices at both ends of the bus section detect negative sequence overcurrent and trigger negative sequence inverse time protection, controlling the disconnection of the bus switch at one end of the bus section. When the bus protection and control device on the bus section detects negative sequence overcurrent, the second stage of protection is activated, controlling the disconnection of the bus switch at the other end of the current bus section.

[0057] When a phase imbalance fault occurs in the cable between busbar sections, the first stage of protection is activated. The first layer of protection is negative sequence inverse time protection at the busbar section. When the busbar protection and control device at both ends of the cable between the busbar sections detects negative sequence overcurrent, it triggers negative sequence inverse time protection and controls the disconnection of the busbar switch at one end of the cable. When the busbar protection and control device at both ends of the cable detects negative sequence overcurrent, the second stage of protection is activated, and the busbar switch at the other end of the current cable is disconnected.

[0058] When a phase imbalance fault occurs at the load end, the first stage of protection is initiated. The first layer of protection is the load negative sequence inverse time protection. The load detection unit detects the negative sequence overcurrent and triggers the negative sequence inverse time protection, which controls the disconnection of the load feeder switch. The second stage of protection is the bus section negative sequence inverse time protection. The bus protection and control devices at both ends of the bus section where the load is located detect the negative sequence overcurrent and trigger the negative sequence inverse time protection, which disconnects the bus switches at both ends of the bus section.

[0059] Thirdly, embodiments of this application provide a ship that includes the aforementioned power protection system.

[0060] The above description is merely an optional embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A power protection system, characterized in that: include, The distribution board has multiple sections, each of which is equipped with a busbar section, at least one busbar protection and control device, at least one load protection and control device, and at least one generator protection and control device. The busbar sections on each distribution board are connected sequentially by cables to form a closed loop network. All the busbar protection and control devices, the load protection and control devices, and the generator protection and control devices within the closed loop network form a ring communication connection. The bus protection and control device is configured to disconnect the bus segment on the same switchboard as the bus protection and control device from other bus segments in response to a fault signal. The generator protection and control device is configured to disconnect the corresponding generator from the bus section in response to a fault signal. The load protection and control device is configured to disconnect the corresponding load from the bus section in response to a fault signal.

2. The power protection system according to claim 1, characterized in that: It also includes a switch, and the closed loop network includes at least one of the switches, which are communicatively connected to the bus protection and control device, the load protection and control device and the generator protection and control device.

3. The power protection system according to claim 2, characterized in that: Each busbar segment is equipped with a switch, which is communicatively connected to all busbar protection and control devices, load protection and control devices, and generator protection and control devices on the busbar segment.

4. The power protection system according to claim 1, characterized in that: The busbar protection and control device includes a busbar control unit, a busbar detection unit, and busbar switches installed at both ends of the busbar section on the same switchboard as the busbar protection and control device; wherein... The bus detection unit is configured to detect the voltage and current signals at both ends of the bus segment and transmit the collected detection results to the bus control unit. The bus control unit is configured to control the bus switch based on a comparison between the detection result and the setting value.

5. The power protection system according to claim 1, characterized in that: The generator protection and control device includes a generator control unit, a generator signal acquisition unit, a generator detection unit, and a generator feeder switch; wherein, The generator feeder switch is connected between the bus section and the generator; The generator detection unit is configured to detect voltage and current signals at the generator feeder. The generator signal acquisition unit is configured to acquire the detection results of the generator detection unit and the detection results from the generator side; and transmit the acquired detection results to the generator control unit; The generator control unit is configured to control the generator feeder switch based on a comparison between the detection result and the set value.

6. The power protection system according to claim 1, characterized in that: The load protection and control device includes a load control unit, a load detection unit, and a load feeder switch; wherein... The load feeder switch is connected between the bus section and the load; The load detection unit is configured to detect the current signal at the load feeder and transmit the collected detection results to the load control unit. The load control unit is configured to control the load feeder switch based on a comparison between the detection result and the set value.

7. The power protection system according to claim 1, characterized in that: The bus protection and control device, the load protection and control device, and the generator protection and control device all include a display screen.

8. A power protection method, characterized in that: The power protection system applied to any one of claims 1 to 7 includes, First-stage protection: In the event of a fault in the generator, load, busbar, or inter-busbar cable, determine the location of the fault and disconnect the switch at the location of the fault. Second-stage protection: If the switch at the fault location fails to operate, determine the location of the fault on the busbar and disconnect the busbar switch of the faulty busbar segment.

9. The power protection method according to claim 8, characterized in that: The fault includes at least one of the following: feeder short circuit fault, ground fault, and phase imbalance fault.

10. The power protection method according to claim 9, characterized in that: In the event of the short-circuit fault or the ground fault, a third stage of protection is also included: if the switches at both ends of the bus section where the fault occurs fail to operate, all bus switches in the closed loop network are disconnected.

11. The power protection method according to claim 10, characterized in that: After disconnecting all bus switches within the closed loop network, this includes disconnecting all generator sets on the bus segment where the fault occurs from the bus segment.

12. The power protection method according to claim 8, characterized in that: The method for determining the location of the fault includes: When the current signal detected by the generator protection and control device is abnormal, the current collected by the generator protection and control device exceeds the set value, the current collected by the current transformer on the generator side is opposite to the current detected by the current transformer in the generator detection unit, or the fault current direction is pointing towards the generator set, and the fault location is at the generator. When the load protection and control device detects an abnormal current signal, the current collected by the load protection and control device exceeds the set value, the fault current direction points to the load, and the fault location is at the load feeder. When the current signal detected by the bus protection and control devices at both ends of the bus section is abnormal, the current collected by the bus protection and control devices exceeds the set value, the direction of the fault current detected at both ends of the bus section points to the bus section, and the fault location is the bus between the two bus protection and control devices. If the bus protection and control device at both ends of the cable detects an abnormal current signal, the current collected by the bus protection and control device exceeds the set value, the current direction of the current transformers configured on both sides of the cable is opposite, or the fault current detected on both sides of the cable points to the cable, and the fault location is the cable.

13. A ship, characterized in that, Includes the power protection system as described in any one of claims 1-7.

Images