A tunnel power distribution special multiple protection photovoltaic islanding off-grid protection system

Abstract

The present application relates to power distribution protection system technical field, especially in a kind of tunnel power distribution special multiple protection photovoltaic protection system of islanding off-grid, including photovoltaic front-end acquisition layer, on-site inversion primary protection layer, subarea confluence multiple perception protection layer, tunnel power grid load feature acquisition layer and multiple protection intelligent decision core layer, the present application builds multilayer collaborative sensing architecture, relies on subarea confluence multiple perception protection layer to cope with coastal tunnel high humidity salt fog environment, to acquisition signal filtering processing, improve signal distortion problem, improve islanding identification precision;It can distinguish power grid disturbance and islanding fault, reduce protection misoperation probability, accurately locate fault partition and implement subarea trip, reduce power outage range, guarantee tunnel power distribution stability.

Description

Technical Field

[0001] This invention relates to the field of power distribution protection system technology, and in particular to a multi-protection photovoltaic anti-islanding and grid disconnection protection system specifically for tunnel power distribution. Background Technology

[0002] In coastal areas, tunnel power distribution systems are often equipped with rooftop and canopy-mounted distributed photovoltaic (PV) systems, with the PV power source connected to the tunnel power distribution system for grid-connected operation. Existing tunnel PV grid-connected protection devices generally employ a local, passive anti-islanding detection scheme based on the inverter, which has limitations when applied to coastal tunnel scenarios.

[0003] Coastal areas are characterized by high air humidity and severe salt spray corrosion, which can easily cause interference and parameter drift in sensor acquisition signals. The lack of signal preprocessing and environmental monitoring protection measures further reduces the accuracy of islanding identification. Furthermore, traditional anti-islanding protection architectures lack a layered collaborative sensing mechanism, relying solely on inverter-side electrical quantities for judgment without comprehensively considering grid-connected port power quality parameters for joint discrimination, resulting in poor ability to distinguish between transient disturbances and actual islanding. Additionally, conventional protection devices only support overall grid-connected circuit tripping, failing to achieve precise location of zoned faults and lacking graded selective grid disconnection capabilities. Power outages after protection actions have a large impact range. Therefore, a multi-protection photovoltaic anti-islanding grid disconnection protection system specifically for tunnel power distribution is proposed. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by proposing a multi-protection photovoltaic anti-islanding and grid disconnection protection system specifically for tunnel power distribution.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution, comprising a photovoltaic front-end acquisition layer, a local inverter primary protection layer, a zoned current convergence multi-sensing protection layer, a tunnel power grid load characteristic acquisition layer, and a multi-protection intelligent decision-making core layer;

[0006] The photovoltaic front-end acquisition layer is used to collect photovoltaic power generation status data and synchronously collect component operating parameter data, and output the collected data to the local inverter primary protection layer.

[0007] The local inverter primary protection layer completes optimal capture of photovoltaic power through MPPT power tracking, stabilizes the power and primary detection signal and sends them to the zoned bus multi-sensor protection layer.

[0008] The partitioned bus multi-sensing protection layer is used for high-precision acquisition of electrical quantities on the grid-connected side, power quality analysis, on-site environmental monitoring and signal preprocessing, and preliminary islanding prediction is carried out based on electrical operating parameters and environmental monitoring parameters.

[0009] The tunnel power grid load characteristic acquisition layer is used to collect the dynamic characteristic parameters of power grid operation and load in real time, providing power grid operating condition benchmark data support for system islanding determination.

[0010] The multi-protection intelligent decision-making core layer integrates multi-source sensing data from the power grid and photovoltaic side to intelligently judge operational disturbances and real island faults, thereby achieving accurate fault location, hierarchical grid disconnection decision-making, and protection execution output.

[0011] Preferably, the photovoltaic front-end acquisition layer includes a rooftop photovoltaic array acquisition module, a shed photovoltaic array acquisition module, a module temperature acquisition module, an irradiance acquisition module, a string current sampling module, and a string voltage sampling module, wherein:

[0012] The rooftop photovoltaic array acquisition module is used to collect the operating status information of the rooftop photovoltaic array.

[0013] The photovoltaic array acquisition module of the station canopy is used to collect the operating status information of the photovoltaic array deployed on the station canopy;

[0014] The component temperature acquisition module is used to acquire the surface temperature parameters of the photovoltaic module in real time;

[0015] The irradiance acquisition module is used to acquire on-site light irradiance data;

[0016] The string current sampling module is used to collect the output current signal of each photovoltaic string;

[0017] The string voltage sampling module is used to collect the output voltage signal of each photovoltaic string.

[0018] Preferably, the partitioned busbar multi-sensor protection layer includes a three-phase voltage high-precision acquisition module, a three-phase current high-precision acquisition module, a THD harmonic distortion calculation module, a local islanding preliminary determination module, a salt spray temperature and humidity monitoring module, a secondary lightning surge suppression module, and a signal filtering and conditioning module, wherein:

[0019] The THD harmonic distortion calculation module receives output signals from the three-phase voltage high-precision acquisition module and the three-phase current high-precision acquisition module to complete the calculation of total harmonic distortion rate of electrical energy.

[0020] The salt spray temperature and humidity monitoring module is used to collect on-site environmental parameters such as salt spray, temperature, and humidity.

[0021] The secondary surge protection module is used to suppress surge impacts in the circuit and ensure the stable operation of the signal acquisition circuit;

[0022] The signal filtering and conditioning module is used to perform noise reduction and standardization processing on the original acquired signal;

[0023] The local islanding preliminary judgment module receives data from the three-phase voltage high-precision acquisition module, the three-phase current high-precision acquisition module, the THD harmonic distortion calculation module, the salt spray temperature and humidity monitoring module, the secondary lightning surge suppression module, and the signal filtering and conditioning module to realize the preliminary judgment of the islanding phenomenon and send the judgment result to the multi-protection intelligent decision core layer.

[0024] Preferably, the local inverter primary protection layer includes an MPPT power tracking module and an inverter voltage regulation output module. The inverter voltage regulation output module includes a primary passive islanding detection module, an inverter overvoltage protection module, an inverter overcurrent protection module, and an inverter leakage current pre-detection module, wherein:

[0025] The MPPT power tracking module receives the acquired data output by the photovoltaic front-end acquisition layer to achieve photovoltaic maximum power point tracking;

[0026] The inverter voltage regulation output module receives the power output from the MPPT power tracking module, completes the power inversion and voltage regulation output, and transmits the regulated power to the three-phase voltage high-precision acquisition module and the three-phase current high-precision acquisition module.

[0027] The primary passive islanding detection module is used to achieve preliminary passive monitoring of islanding phenomena based on the electrical quantities on the inverter side.

[0028] The inverter overvoltage protection module is used to monitor the inverter output voltage and trigger overvoltage fault protection.

[0029] The inverter overcurrent protection module is used to monitor the inverter output current and trigger overcurrent fault protection.

[0030] The inverter leakage pre-detection module is used to detect potential leakage risks in the inverter circuit in real time.

[0031] Preferably, the multi-protection intelligent decision-making core layer includes a multi-parameter islanding fusion criterion module, an instantaneous disturbance interlocking unit, a zone fault precise location module, a hierarchical selective disconnection decision module, and a dual-path trip command output module, wherein:

[0032] The multi-parameter island fusion criterion module receives the output signal of the local island preliminary judgment module and the data collected by the tunnel power grid load characteristic acquisition layer, which is used to distinguish between instantaneous disturbances and real island faults.

[0033] The instantaneous disturbance blocking unit is connected to the multi-parameter islanding fusion criterion module and is used to block short-term power grid disturbances to avoid protection malfunctions.

[0034] The partition fault precise location module receives the continuous island fault determination signal output by the multi-parameter island fusion criterion module to realize the location of the grid-connected partition to which the fault belongs;

[0035] The hierarchical selective disconnection decision module is connected to the partition fault precise location module, and generates differentiated disconnection control strategies based on the fault location.

[0036] The dual-path tripping command output module receives the strategy issued by the hierarchical selective disconnection decision module and outputs two independent tripping control signals to the execution module.

[0037] Preferably, it also includes a data interaction and maintenance layer, which is used to collect system island protection-related operation and fault decision data, complete data aggregation, and support remote online monitoring and maintenance management.

[0038] Preferably, the data interaction and maintenance layer includes an industrial data communication acquisition module and a tunnel energy monitoring backend, wherein;

[0039] The industrial data communication and acquisition module receives islanding determination information, fault location information, and offline decision information output by the multi-protection intelligent decision core layer, thereby realizing centralized acquisition of operational data.

[0040] The tunnel energy monitoring backend is connected to the industrial data communication and acquisition module, which is used to summarize and display the overall system operation status and fault information, and realize remote operation and maintenance monitoring.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. This invention, through a multi-sensor protection layer with partitioned flow, can perceive the working conditions of the coastal high-humidity salt fog environment in real time, and perform filtering preprocessing on the original acquired signal to suppress signal distortion and parameter drift caused by environmental interference, improve the reliability of electrical parameter acquisition, effectively improve the accuracy of island identification and judgment, and adapt to the harsh operating environment of coastal tunnels.

[0043] 2. This invention constructs a multi-layer collaborative sensing architecture consisting of a photovoltaic front-end acquisition layer, a local inverter primary protection layer, a zoned current convergence multi-sensor protection layer, and a multi-protection intelligent decision core layer. This architecture can filter out short-term fluctuation interference, significantly improve the system's ability to distinguish between instantaneous grid disturbances and real islanded operating conditions, and reduce protection malfunctions.

[0044] 3. The multi-protection intelligent decision core layer of this invention can accurately locate the grid-connected zone to which the island fault belongs and generate differentiated disconnection control strategies to achieve zone-specific protection tripping, abandoning the traditional unified tripping mode of the entire protection unit, reducing the scope of power outage caused by the fault, and ensuring the continuous and stable operation of power distribution in other areas of the tunnel. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of a multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution according to the present invention;

[0046] Figure 2This is a schematic diagram of the photovoltaic front-end acquisition layer of a multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution according to the present invention.

[0047] Figure 3 This invention provides a local inverter primary protection layer for a multi-protection photovoltaic anti-islanding and grid disconnection protection system specifically designed for tunnel power distribution.

[0048] Figure 4 This invention relates to a multi-protection intelligent decision-making core layer of a multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution. Detailed Implementation

[0049] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0050] like Figures 1-4 The diagram shows a multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution, which includes a photovoltaic front-end acquisition layer, a local inverter primary protection layer, a zoned current convergence multi-sensing protection layer, a tunnel power grid load characteristic acquisition layer, and a multi-protection intelligent decision core layer.

[0051] The photovoltaic front-end acquisition layer is used to collect photovoltaic power generation status data and synchronously collect component operating parameter data, and output the collected data to the local inverter primary protection layer.

[0052] The local inverter primary protection layer completes the optimal capture of photovoltaic power through MPPT power tracking, stabilizes the power and primary detection signal and sends them to the zoned bus multi-sensor protection layer;

[0053] The zoned busbar multi-sensor protection layer is used for high-precision acquisition of electrical quantities on the grid-connected side, power quality analysis, on-site environmental monitoring, and signal preprocessing. It relies on electrical operating parameters and environmental monitoring parameters to conduct preliminary islanding prediction, including:

[0054] The tunnel power grid load characteristic acquisition layer is used to collect real-time power grid side operation and load dynamic characteristic parameters, providing power grid operating condition benchmark data support for system islanding determination;

[0055] The multi-protection intelligent decision-making core layer integrates multi-source sensing data from the power grid and photovoltaic side to intelligently judge operational disturbances and real island faults, and realizes accurate fault location, hierarchical grid disconnection decision and protection execution output.

[0056] The photovoltaic front-end acquisition layer includes a rooftop photovoltaic array acquisition module, a rooftop photovoltaic array acquisition module, a module temperature acquisition module, an irradiance acquisition module, a string current sampling module, and a string voltage sampling module, among which:

[0057] The rooftop photovoltaic array acquisition module is used to collect the operating status information of the rooftop photovoltaic array.

[0058] The photovoltaic array acquisition module for the station canopy is used to collect the operating status information of the photovoltaic array deployed on the station canopy.

[0059] The module temperature acquisition module is used to collect the surface temperature parameters of the photovoltaic module in real time.

[0060] The irradiance acquisition module is used to collect on-site light irradiance data;

[0061] The string current sampling module is used to collect the output current signal of each photovoltaic string;

[0062] The string voltage sampling module is used to collect the output voltage signal of each photovoltaic string.

[0063] The photovoltaic front-end acquisition layer can collect photovoltaic array layout conditions, component environmental conditions, and string electrical operating parameters to form a multi-dimensional raw data source. This data is then uniformly aggregated and output to the local inverter primary protection layer, providing complete photovoltaic-side basic data support for subsequent power tracking, inverter control, and islanding pre-judgment.

[0064] The zoned bus multi-sensor protection layer includes a three-phase voltage high-precision acquisition module, a three-phase current high-precision acquisition module, a THD harmonic distortion calculation module, a local islanding preliminary determination module, a salt spray temperature and humidity monitoring module, a secondary lightning surge suppression module, and a signal filtering and conditioning module, among which:

[0065] The THD harmonic distortion calculation module receives output signals from the three-phase voltage high-precision acquisition module and the three-phase current high-precision acquisition module to complete the calculation of the total harmonic distortion rate of electrical energy.

[0066] The salt spray temperature and humidity monitoring module is used to collect on-site environmental parameters such as salt spray, temperature, and humidity.

[0067] The secondary surge protection module is used to suppress surge impacts in the circuit and ensure the stable operation of the signal acquisition circuit;

[0068] The signal filtering and conditioning module is used to reduce noise and standardize the raw acquired signal;

[0069] The local islanding preliminary judgment module receives data from the three-phase voltage high-precision acquisition module, the three-phase current high-precision acquisition module, the THD harmonic distortion calculation module, the salt spray temperature and humidity monitoring module, the secondary lightning surge suppression module, and the signal filtering and conditioning module to realize the preliminary judgment of the islanding phenomenon and send the judgment result to the multi-protection intelligent decision core layer.

[0070] The local inverter primary protection layer includes an MPPT power tracking module and an inverter voltage regulator output module. The inverter voltage regulator output module includes a primary passive islanding detection module, an inverter overvoltage protection module, an inverter overcurrent protection module, and an inverter leakage current pre-detection module, wherein:

[0071] The MPPT power point tracking module receives the data collected from the photovoltaic front-end acquisition layer to achieve photovoltaic maximum power point tracking.

[0072] The inverter voltage regulation output module receives the power output from the MPPT power tracking module, completes the power inversion and voltage regulation output, and delivers the regulated power to the three-phase voltage high-precision acquisition module and the three-phase current high-precision acquisition module.

[0073] The primary passive islanding detection module is used to achieve preliminary passive monitoring of islanding phenomena based on inverter-side electrical quantities.

[0074] The inverter overvoltage protection module is used to monitor the inverter output voltage and trigger overvoltage fault protection.

[0075] The inverter overcurrent protection module is used to monitor the inverter output current and trigger overcurrent fault protection.

[0076] The inverter leakage current pre-detection module is used to detect potential leakage current hazards in the inverter circuit in real time.

[0077] The local inverter primary protection layer completes the optimal capture of photovoltaic power and AC / DC inverter voltage regulation. Simultaneously, it relies on the inverter-side electrical parameters to carry out preliminary islanding monitoring and multiple electrical fault prevention, outputting stable power to the downstream sensing protection layer, providing basic operating information on the inverter side for grid-connected side in-depth power quality analysis and comprehensive islanding judgment.

[0078] The core layer of multi-protection intelligent decision-making includes a multi-parameter island fusion criterion module, an instantaneous disturbance interlocking unit, a zone fault precise location module, a graded selective disconnection decision module, and a dual-path trip command output module.

[0079] The multi-parameter islanding fusion criterion module receives the output signal from the local islanding preliminary judgment module and the data collected by the tunnel power grid load characteristic acquisition layer to distinguish between transient disturbances and actual islanding faults, wherein:

[0080] The instantaneous disturbance blocking unit is connected to the multi-parameter islanding fusion criterion module to block short-term power grid disturbances and prevent protection malfunctions.

[0081] The partition fault precise location module receives the continuous island fault determination signal output by the multi-parameter island fusion criterion module to realize the location of the grid-connected partition to which the fault belongs;

[0082] The hierarchical selective disconnection decision module is connected to the partition fault precise location module, and generates differentiated disconnection control strategies based on the fault location;

[0083] The dual-path trip command output module receives the strategy issued by the hierarchical selective disconnection decision module and outputs two independent trip control signals to the execution module.

[0084] The following is an example of the algorithm formula for the initial determination of isolated areas in the local area:

[0085] Condition 1 (Electrical Boundary Threshold)

[0086]

[0087] Assume that the islanding fault flag is ,

[0088]

[0089] If a true islanding scenario is determined, regional location and tiered disconnection from the network are initiated.

[0090] 0 is determined to be a transient disturbance to the power grid, and the transient disturbance blocking unit takes effect.

[0091] The above symbols are defined as follows:

[0092] Rated phase voltage of the power grid; Actual grid-connected voltage

[0093] Rated frequency of the power grid; Actual grid-connected frequency

[0094] Difference between photovoltaic output power and local load power in the tunnel

[0095] Total harmonic distortion of voltage; Harmonic threshold

[0096] : Initial identification marker for islanded output from local inverter primary protection layer + zoned busbar layer ( =1 Preliminary warning, =0 No warning)

[0097] : Disturbance blocking delay time (filtering out instantaneous disturbances); Fault duration

[0098] : Environmental correction factor (valued by a combination of irradiance and component temperature, lowering the criterion threshold under harsh environments).

[0099] In the example algorithm described above, the multi-parameter islanding fusion criterion combines voltage offset, frequency offset, harmonic distortion, photovoltaic-load power imbalance, pre-islanding early warning signal and environmental correction coefficient, and adds a time-blocking criterion. Unlike the traditional single passive islanding detection algorithm, it can avoid the protection from being mistakenly disconnected due to the instantaneous disturbance caused by the switching of impulsive loads in the tunnel power grid, and is suitable for the multiple protection requirements of photovoltaic grid connection in tunnel power distribution scenarios.

[0100] It also includes a data interaction and maintenance layer, which is used to collect operational and fault decision data related to system island protection, complete data aggregation, and support remote online monitoring and maintenance management. The data interaction and maintenance layer includes an industrial data communication acquisition module and a tunnel energy monitoring backend. The industrial data communication acquisition module receives island determination information, fault location information, and disconnection decision information output by the multi-protection intelligent decision core layer, realizing centralized collection of operational data.

[0101] The tunnel energy monitoring backend is connected to the industrial data communication and acquisition module to summarize and display the overall system operation status and fault information, enabling remote operation and maintenance monitoring.

[0102] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A multi-protection photovoltaic anti-islanding and grid disconnection protection system specifically for tunnel power distribution, characterized in that: It includes a photovoltaic front-end acquisition layer, a local inverter primary protection layer, a zoned current convergence multi-sensor protection layer, a tunnel power grid load characteristic acquisition layer, and a multi-protection intelligent decision-making core layer; The photovoltaic front-end acquisition layer is used to collect photovoltaic power generation status data and synchronously collect component operating parameter data, and output the collected data to the local inverter primary protection layer. The local inverter primary protection layer completes optimal capture of photovoltaic power through MPPT power tracking, stabilizes the power and primary detection signal and sends them to the zoned bus multi-sensor protection layer. The partitioned bus multi-sensing protection layer is used for high-precision acquisition of electrical quantities on the grid-connected side, power quality analysis, on-site environmental monitoring and signal preprocessing, and preliminary islanding prediction is carried out based on electrical operating parameters and environmental monitoring parameters. The tunnel power grid load characteristic acquisition layer is used to collect the dynamic characteristic parameters of power grid operation and load in real time, providing power grid operating condition benchmark data support for system islanding determination. The multi-protection intelligent decision-making core layer integrates multi-source sensing data from the power grid and photovoltaic side to intelligently judge operational disturbances and real island faults, thereby achieving accurate fault location, hierarchical grid disconnection decision-making, and protection execution output.

2. The multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution as described in claim 1, characterized in that: The photovoltaic front-end acquisition layer includes a rooftop photovoltaic array acquisition module, a shed photovoltaic array acquisition module, a module temperature acquisition module, an irradiance acquisition module, a string current sampling module, and a string voltage sampling module, wherein: The rooftop photovoltaic array acquisition module is used to collect the operating status information of the rooftop photovoltaic array. The photovoltaic array acquisition module of the station canopy is used to collect the operating status information of the photovoltaic array deployed on the station canopy; The component temperature acquisition module is used to acquire the surface temperature parameters of the photovoltaic module in real time; The irradiance acquisition module is used to acquire on-site light irradiance data; The string current sampling module is used to collect the output current signal of each photovoltaic string; The string voltage sampling module is used to collect the output voltage signal of each photovoltaic string.

3. The multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution according to claim 1, characterized in that: The partitioned busbar multi-sensor protection layer includes a three-phase voltage high-precision acquisition module, a three-phase current high-precision acquisition module, a THD harmonic distortion calculation module, a local islanding preliminary determination module, a salt spray temperature and humidity monitoring module, a secondary lightning surge suppression module, and a signal filtering and conditioning module, wherein: The THD harmonic distortion calculation module receives output signals from the three-phase voltage high-precision acquisition module and the three-phase current high-precision acquisition module to complete the calculation of total harmonic distortion rate of electrical energy. The salt spray temperature and humidity monitoring module is used to collect on-site environmental parameters such as salt spray, temperature, and humidity. The secondary surge protection module is used to suppress surge impacts in the circuit and ensure the stable operation of the signal acquisition circuit; The signal filtering and conditioning module is used to perform noise reduction and standardization processing on the original acquired signal; The local islanding preliminary judgment module receives data from the three-phase voltage high-precision acquisition module, the three-phase current high-precision acquisition module, the THD harmonic distortion calculation module, the salt spray temperature and humidity monitoring module, the secondary lightning surge suppression module, and the signal filtering and conditioning module to realize the preliminary judgment of the islanding phenomenon and send the judgment result to the multi-protection intelligent decision core layer.

4. The multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution according to claim 3, characterized in that: The local inverter primary protection layer includes an MPPT power tracking module and an inverter voltage regulation output module. The inverter voltage regulation output module includes a primary passive islanding detection module, an inverter overvoltage protection module, an inverter overcurrent protection module, and an inverter leakage current pre-detection module, wherein: The MPPT power tracking module receives the acquired data output by the photovoltaic front-end acquisition layer to achieve photovoltaic maximum power point tracking; The inverter voltage regulation output module receives the power output from the MPPT power tracking module, completes the power inversion and voltage regulation output, and transmits the regulated power to the three-phase voltage high-precision acquisition module and the three-phase current high-precision acquisition module. The primary passive islanding detection module is used to achieve preliminary passive monitoring of islanding phenomena based on the electrical quantities on the inverter side. The inverter overvoltage protection module is used to monitor the inverter output voltage and trigger overvoltage fault protection. The inverter overcurrent protection module is used to monitor the inverter output current and trigger overcurrent fault protection. The inverter leakage pre-detection module is used to detect potential leakage risks in the inverter circuit in real time.

5. The multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution as described in claim 3, characterized in that: The multi-protection intelligent decision-making core layer includes a multi-parameter islanding fusion criterion module, an instantaneous disturbance interlocking unit, a zone fault precise location module, a hierarchical selective disconnection decision module, and a dual-path trip command output module, wherein: The multi-parameter island fusion criterion module receives the output signal of the local island preliminary judgment module and the data collected by the tunnel power grid load characteristic acquisition layer, which is used to distinguish between instantaneous disturbances and real island faults. The instantaneous disturbance blocking unit is connected to the multi-parameter islanding fusion criterion module and is used to block short-term power grid disturbances to avoid protection malfunctions. The partition fault precise location module receives the continuous island fault determination signal output by the multi-parameter island fusion criterion module to realize the location of the grid-connected partition to which the fault belongs; The hierarchical selective disconnection decision module is connected to the partition fault precise location module, and generates differentiated disconnection control strategies based on the fault location. The dual-path tripping command output module receives the strategy issued by the hierarchical selective disconnection decision module and outputs two independent tripping control signals to the execution module.

6. The multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution according to claim 5, characterized in that: It also includes a data interaction and maintenance layer, which is used to collect system island protection-related operation and fault decision data, complete data aggregation, and support remote online monitoring and maintenance management.

7. The multi-protection photovoltaic anti-islanding and grid disconnection protection system for tunnel power distribution according to claim 6, characterized in that: The data interaction and maintenance layer includes an industrial data communication and acquisition module and a tunnel energy monitoring backend, wherein: The industrial data communication and acquisition module receives islanding determination information, fault location information, and offline decision information output by the multi-protection intelligent decision core layer, thereby realizing centralized acquisition of operational data. The tunnel energy monitoring backend is connected to the industrial data communication and acquisition module, which is used to summarize and display the overall system operation status and fault information, and realize remote operation and maintenance monitoring.

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