Differential dynamic simulation calibration system based on integrated power supply DC monitoring module

Abstract

The application discloses a step difference dynamic simulation checking system based on an integrated power supply direct current monitoring module, which comprises the following steps: step one, establishing an algorithm and a full loop display model for step difference checking of a substation direct current power supply system; step two, based on the integrated power supply system direct current monitoring module in the substation, increasing direct current feeder cable and load information, expanding the direct current monitoring range to a complete loop, and increasing the air switch internal resistance and tripping characteristic parameters, which are substituted into the algorithm and the loop model, so that the direct current monitoring module has the step difference calculation and checking function for each loop.The application has the following beneficial effects: (1) the step difference cooperation field simulation checking is realized by using the existing direct current monitoring module, and dynamic and real-time judgment is realized; (2) the full loop model and the step difference discrimination rules for different loop characteristics are established, and the control word is used to realize the step difference fault tolerance; and (3) the fault recording analysis, calculation comparison and long-term loop predefinition and other deepening application functions are realized on the step difference simulation checking step difference.

Description

Technical Field

[0001] This invention belongs to the field of electrical automation, and specifically relates to a differential dynamic simulation verification system based on an integrated power supply DC monitoring module. Background Technology

[0002] The DC power supply system in a substation provides power to the protection and control equipment within the station. In some areas, the switching and disconnecting equipment also requires the DC power supply system for operation. The DC power supply system is crucial for ensuring the reliable operation of the substation.

[0003] DC power supply systems generally have a main panel hybrid power supply structure and a main panel multi-stage power supply structure. The main busbar connecting the DC charging device and the battery is the first stage, the DC panel busbar is the second stage, and the main circuit breaker of the load-side panel cabinet is the third stage. Multi-stage power supply methods are as follows: Figure 1 As shown. When using a multi-level power supply method, the protective selectivity of DC system protective devices (mainly DC circuit breakers) must be considered. That is, each level of DC circuit breaker protects the cables and equipment within its own range. In the event of a fault (mainly a short circuit) within its range, the circuit breaker at that level should trip quickly, but it cannot trip the circuit breaker at a higher level. Since the higher-level circuit breaker controls multiple circuits of the entire busbar section at this level, tripping the circuit breaker at a higher level would cause widespread power loss in fault-free circuits. For example... Figure 2 When cable L3 is short-circuited, circuit breaker K3 should have operated. However, if the protection selectivity is not properly designed, causing the first-stage circuit breaker K2 to malfunction, all circuits on the L3 busbar where the third-stage circuit breaker K3 is located will lose power, causing the accident to escalate.

[0004] With the increasing sophistication of power management systems, the requirements for selectivity in DC system protection are gradually increasing. The "Eighteen Anti-Accident Measures" issued by the State Grid Corporation of China in 2018 explicitly requires the provision of a DC system differential calculation report. DC system differential coordination needs to be designed and verified through parameter calculations of the entire circuit. This involves calculating the short-circuit current at the beginning and end of each power supply level, comparing it with the tripping characteristics of the circuit breakers at this level and the upstream circuit breakers, and selecting protective devices based on the principle that the upstream circuit breaker trips or trips with a delay. While the calculation principle is not complex, it requires calculating and comparing the impedance, short-circuit current, and tripping characteristics of all circuit components and cables from the battery to the final circuit breaker. The parameters required for the calculation include manufacturer-specific equipment information such as the internal resistance of the battery and circuit breakers, design-determined information such as the length and cross-section of each power supply cable, and non-power supply manufacturer information such as the internal resistance of the circuit breakers of each load device. Therefore, it is impossible to completely verify the backup circuit. When providing differential calculation reports in engineering design, the design institute typically collects the aforementioned information and submits it to the commissioning and operation units in document form. Short-circuit tests are then conducted on key circuits on-site for verification. This approach addresses the selectivity of the DC system during the construction phase, particularly in the current phase. However, it also presents some challenges for later operation, maintenance, and expansion, primarily including: 1) the lack of dynamic on-site information, coupled with the availability of only calculation documents, hinders operation and maintenance management; 2) expansion requires recalculation and verification based on previous drawings, resulting in a significant workload for data collection and parameter verification.

[0005] In the past, many projects did not pay enough attention to the differential coordination of power systems, failing to conduct differential coordination calculations, analyses, and on-site tests, leading to frequent cascading trips. In recent years, many substations have included differential coordination re-verification in separate technical upgrade projects, but due to the lack of prior calculation reports and missing information such as circuit cable lengths and impedances, accurate verification during upgrades is difficult. Although new substations are required to provide differential coordination reports, factors such as inaccurate cable length measurements and circuit breaker impedance calibrations during on-site construction mean that the calculation reports and on-site test results cannot be guaranteed to correspond perfectly. With the increasing demands for refined operation and maintenance, the need for simulation verification of DC differential systems based on actual circuits is becoming increasingly urgent. Summary of the Invention

[0006] The technical problem to be solved by this invention is: how to realize the simulation verification of DC differential system based on actual circuit, and proposes a differential dynamic simulation verification system based on an integrated power supply DC monitoring module.

[0007] The specific technical solution of the present invention is as follows: The differential dynamic simulation verification system based on an integrated power supply DC monitoring module includes the following steps: Step 1: Establish the algorithm and full-loop display model for differential verification of the DC power supply system in the substation: Step 2: Based on the DC monitoring module of the integrated power supply system in the station, add DC feeder cable and load information to extend the DC monitoring range to the complete circuit; add circuit breaker internal resistance and tripping characteristic parameters, substitute them into the algorithm and circuit model, so that the DC monitoring module has the function of calculating and verifying the differential of each circuit.

[0008] In step one, based on the two structures adopted in the project, namely the main screen hybrid power supply and the main sub-screen multi-level power supply, algorithms for differential verification of the DC power supply system of the substation and full-circuit display models are established respectively.

[0009] In the main screen hybrid power supply model, a battery is included. The battery is connected to the battery outlet appliance via a battery cable, and then the first feeder cable from the feeder panel to the load F is connected through the DC main screen feeder circuit breaker. Finally, it is connected to the load through the DC sub-screen feeder circuit breaker. The short-circuit current is calculated from four locations: the top of the battery outlet appliance, the beginning and end of the DC main screen feeder circuit breaker outlet cable, and the outlet of the DC sub-screen feeder circuit breaker. This short-circuit current is compared with the tripping current of the upstream and upstream circuit breakers to examine its operating characteristics.

[0010] In the main screen-sub-screen multi-level power supply model, a battery is included. The battery is connected to the battery outlet electrical appliance via a battery cable, and then the first feeder cable from the feeder panel to the load is connected through the DC main screen feeder circuit breaker. The first feeder cable is connected to the second feeder cable through the DC sub-screen feeder circuit breaker, and the second feeder cable is connected to the load through the load panel feeder circuit breaker. The short-circuit current is calculated from six locations: the upper port of the DC main screen feeder circuit breaker and the beginning and end of its outlet cable, the beginning and end of the outlet cable of the DC sub-screen feeder circuit breaker, and the lower port of the load panel feeder circuit breaker. This short-circuit current is compared with the tripping current of the upper-level and upper-upper-level circuit breakers to examine its operating characteristics.

[0011] Establish differential judgment rules for different circuit characteristics: when multiple different load devices are connected together and involve different functional types, differential coordination is fully realized; when a single load device occupies a DC circuit, if differential coordination is difficult to achieve, simultaneous tripping of the current level and the upper level is allowed; differential coordination verification of each circuit is realized through the control word of each circuit.

[0012] It also includes step three, which, based on the established full-loop display model, enables one or more of the following analyses: comparison of calculated and simulated values, pre-definition of long-term loops, and fault recording analysis.

[0013] Fault waveform analysis: When a circuit breaker in a certain circuit trips, the total impedance at the short circuit point is calculated based on the detected tripping current. The impedance of the components and cables before the circuit breaker is subtracted from the total impedance to obtain the impedance value of the short-circuited cable, thereby determining the location of the ground fault.

[0014] Comparison and analysis of calculated and simulated values: Collect the current of the current transformer circuit at each stage of the circuit breaker, compare the actual collected current with the calculated value of the short-circuit current at that point, and judge the accuracy of the results of the differential simulation system.

[0015] Long-term loop pre-definition: Using the calculation results of loops with the same parameters, the total loop impedance is limited according to the short-circuit current value that satisfies the differential coordination, and the range of cable length values ​​is calculated.

[0016] The beneficial effects of this invention are as follows: (1) Use the existing DC monitoring module to realize the on-site simulation verification of differential coordination, and realize dynamic and real-time judgment.

[0017] (2) Establish a full-loop model and a differential judgment rule for different loop characteristics, and use control words to achieve differential fault tolerance.

[0018] (3) Implement advanced application functions such as fault waveform analysis, calculation comparison, and pre-definition of long-term circuits on the differential simulation verification differential. Attached Figure Description

[0019] Figure 1 This is based on the existing DC main and sub-screen multi-stage power supply structure; Figure 2 Selective circuit breaker tripping schematic diagram; Figure 3 A full-loop display model for DC differential calculation of the main screen's hybrid power supply mode was established. Figure 4 A full-loop display model for DC differential calculation based on the main screen-segment multi-level power supply mode. Detailed Implementation

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

[0021] In recent years, substations have been implementing integrated power systems, which include DC monitoring modules. These monitoring modules act as the central hub of the integrated power system, collecting and displaying information such as DC system battery inspection data, rectifier unit status, bus voltages at each stage, and circuit breaker currents. This data can be transmitted to the substation monitoring system either locally or to the substation monitoring system. Therefore, utilizing the integrated power system monitoring module to calculate and simulate DC level differences can reduce the workload of preparing calculation reports during the construction phase and serve as a functional module for dynamic monitoring of the power system after commissioning, thus improving monitoring capabilities. Furthermore, it facilitates the selection and verification of backup circuit level difference coordination in renovation and expansion projects. This patent proposes establishing a DC level difference simulation verification and monitoring system using the power system monitoring module without adding new equipment.

[0022] like Figure 1 As shown, the differential dynamic simulation verification system based on the integrated power supply DC monitoring module includes the following steps: Step 1: Establish the algorithm and full-loop display model for the differential verification of the DC power supply system in the substation: Based on the two structures adopted in the project, namely the main screen hybrid power supply and the main sub-screen multi-level power supply, the algorithm and judgment rules are studied respectively.

[0023] Step 2: Based on the DC monitoring module of the integrated power system in the station, add DC feeder cable and load information to extend the DC monitoring range to the complete circuit; add parameters such as circuit breaker internal resistance and tripping characteristics, and substitute them into the algorithm and circuit model to enable the DC monitoring module to have the function of calculating and verifying the differential of each circuit.

[0024] Step 3: Based on this, further data mining is carried out to achieve in-depth application functions such as comparing calculated and simulated values, predefining long-term loops, fault recording and analysis.

[0025] In step one above, algorithm models and full-circuit display models are established according to the two most commonly used structures in substations: main panel hybrid power supply and main sub-panel multi-level power supply.

[0026] (1) Main screen hybrid power supply model A full-loop display model for DC differential calculation is established for a typical main screen hybrid power supply mode. This model covers the complete loop from the battery to the end load, such as... Figure 3 As shown. In the main screen hybrid power supply model, it includes a battery C, which is connected to the battery outlet electrical appliance S1 via a battery cable L1, and then connected to the first feeder cable L2 from the feeder panel to the load F via a DC main screen feeder circuit breaker S2. Finally, it is connected to the load F via a DC sub-screen feeder circuit breaker S3. The above components and cables form a complete DC circuit.

[0027] Calculate the short-circuit current at four locations: point d1 at the top of the battery outlet electrical appliance S1 (the first DC circuit breaker), point d2 at the beginning of the DC main screen feeder circuit breaker S2 and point d3 at the end of the outlet cable, and point d4 at the outlet of the DC sub-screen feeder circuit breaker S3. Compare this short-circuit current with the tripping current of the upstream and upstream circuit breakers to examine its operating characteristics.

[0028] The impedance parameters of each component are as follows: Battery impedance Rc: 1) Voltage U: 220V / 110V; 2) Capacity: XXXAh; 3) Connection method: hard connection / soft connection. Based on the above parameters, the battery impedance Rc can be obtained from table DLT5044-2014, Technical Specification for Design of DC Power Supply Systems in Power Engineering.

[0029] Impedance Rl1 of battery cable L1: 1) Cross-section: 1×ml, unit mm 2 2) Length: l1 in meters. Based on the above parameters, the impedance of the battery cable Rl1 can be calculated as (2 × 0.0184 × ml / l1) * 1000, in mΩ.

[0030] The impedance Rs1 of the battery outlet electrical appliance S1: 1) Rated current Is1, unit A, internal resistance is fixed at Rs1=0, unit mΩ. It should be noted that its internal resistance can be manually adjusted.

[0031] The impedance Rs2 of the DC main panel feeder circuit breaker S2 is: rated current Is2, unit A, tripping multiple: s2n1-s2n2. Based on the above parameters, the internal resistance Rs2 of the circuit breaker can be found in Table DLT5044-2014, Technical Specification for Design of DC Power Supply Systems in Power Engineering. It should be noted that the values ​​in the table are for a single pole and need to be multiplied by 2, and the internal resistance can be manually adjusted.

[0032] The impedance Rl2 of the first feeder cable L2 is: 1) Cross-section: 1×m2; 2) Length: l2 in meters. Based on the above parameters, the battery cable impedance Rl2 can be calculated as (2×0.0184×m2 / l2)*1000, in mΩ.

[0033] The impedance Rs3 of the DC split-screen feeder circuit breaker S3 is: rated current Is3, unit A, tripping multiple: s3n1-s3n2. The internal resistance Rs3 of the circuit breaker can be found in Table A.6 based on the above parameters. It should be noted that the values ​​in the table are for a single pole and need to be multiplied by 2, and the internal resistance can be manually adjusted.

[0034] The discrimination rules for the full-loop model of the main screen hybrid power supply differential calculation are shown in Table 1.

[0035] Table 1.

[0036] (2) Main screen-segment screen multi-level power supply model A full-loop display model for calculating DC level differences is established for a typical main-screen-segment multi-level power supply mode, such as... Figure 4 As shown. It includes a battery C, which is connected to the battery outlet appliance S1 via battery cable L1. Then, it is connected to the first feeder cable L2 from the feeder panel to the load F via DC main panel feeder circuit breaker S2. The first feeder cable L2 is connected to the second feeder cable L3 via DC sub-panel feeder circuit breaker S3. The second feeder cable L3 is connected to the load F via load panel feeder circuit breaker S4. These components and cables form a complete DC circuit.

[0037] Calculate the short-circuit current from six locations: point d1 at the top of DC main panel feeder circuit breaker S2, points d2 and d3 at the beginning and end of its outlet cable, points d4 and d5 at the beginning and end of the outlet cable of DC sub-panel feeder circuit breaker S3, and point d6 at the bottom of the load panel feeder circuit breaker. Compare this short-circuit current with the tripping current of the upstream and upstream circuit breakers to examine their operating characteristics.

[0038] The short-circuit current at each short-circuit point is I=U / R, where U is the DC system power supply voltage, typically 110V or 220V; R is the sum of all impedances from the power supply terminal voltage (battery) to this short-circuit point, including cable impedance RLn and circuit breaker impedance Rkn. The impedance parameters of each component are the same as those in the main screen hybrid power supply model, and the remaining parameters are used to establish a calculation table and differential examination rules.

[0039] The impedance Rl3 of the second feeder cable L3 is: 1) Cross-section: 1×m3; 2) Length: l3 in meters. Based on the above parameters, the battery cable impedance Rl3 can be calculated as (2×0.0184×m3 / l3)*1000, in mΩ.

[0040] The impedance Rs4 of the load panel feeder circuit breaker S4 is: rated current Is4, unit A, tripping multiple: s4n1-s4n2. The internal resistance Rs4 of the circuit breaker can be found in Table A.6 based on the above parameters. It should be noted that the values ​​in the table are for a single pole and need to be multiplied by 2, and the internal resistance can be manually adjusted.

[0041] According to the calculation model, the parameters required for differential calculation are the battery internal resistance Rc, the internal resistance Rk of each stage of circuit breaker and fuse, the DC cable internal resistance RL, and the tripping current Ikn of circuit breaker Kn. Among these, Rc, Rk, and Ikn are inherent parameters of the equipment, while RL is related to the cross-section and length of the cable used, and its calculation formula is as follows: RL=2ρL / S Where L is the cable length, S is the cross-sectional area, and ρ is the resistivity. Generally, DC systems use copper conductor cables, and the resistivity of copper conductors is 0.0184 Ω*mm. 2 / m. The discrimination rules for the full-loop model of multi-level power supply differential calculation for main and sub-screens are shown in Table 2.

[0042] Table 2.

[0043] (3) Establishment of discrimination rules Establish differential matching rules for different circuit characteristics. For example, when multiple different load devices share a circuit board and involve different functional types, differential matching should be fully implemented. However, when a single load device (or multiple interconnected load devices that typically shut down simultaneously) occupies a DC circuit, if differential matching is difficult to achieve, simultaneous tripping of the current and upstream levels is permissible, without strict differential matching requirements. Differential matching verification for each circuit is achieved through the control words of each circuit. When conditions permit, differential matching does not need to be 100% across the entire circuit range, thus achieving differential fault tolerance. Differential matching rules with fault-tolerant characteristics can reduce the complexity of equipment configuration, improve operational reliability, and reduce equipment configuration costs.

[0044] In addition, the current monitoring scope of integrated power systems usually only includes equipment supplied by the power supply manufacturer, from batteries to DC sub-panels, excluding DC feeder cables and load-side circuit breakers; in terms of parameters, it focuses on circuit current, voltage and fault alarms, but does not include circuit breaker internal resistance and tripping characteristics information, let alone information on the DC cables used in the circuit.

[0045] To enable the DC monitoring module to perform differential calculation and simulation functions, the parameter acquisition range of the DC monitoring module needs to be expanded. This requires adding the acquisition of battery internal resistance Rc and the internal resistance Rk of various circuit breakers, fuses, and other protective devices. These parameters are fixed data and do not require calculation; they can be directly entered. Cable information acquisition also needs to be added, collecting cable length and cross-section. The program will calculate the cable impedance RL using the formula RL=2ρL / S. A tripping attribute Ik=N*In should be added to each circuit breaker, where Ik is the tripping current of this circuit breaker, N is the multiple of the tripping current, and In is the rated current.

[0046] After adding the above parameters, the system can calculate the short-circuit current before and after each circuit breaker according to the calculation matrix, and then compare it with this circuit breaker and its superior circuit breaker according to the grade difference examination rules, and automatically report whether its grade difference meets the requirements.

[0047] With the addition of information such as feeder cables and load circuit breakers, the monitoring scope of the DC monitoring system has expanded from the power supply manufacturer's equipment to the power supply circuit and the supplied load, realizing complete information collection and monitoring of the power supply circuit, and further enhancing its functionality. Based on this, the complete circuit data can be further developed and mined to achieve in-depth application functions such as comparing calculated and simulated values, pre-defining long-term circuits, and fault analysis and troubleshooting.

[0048] (1) Fault recording analysis Because a full-loop model has been established, when a circuit breaker in a certain loop trips, the total impedance at the short-circuit point can be calculated based on the detected tripping current. Subtracting the impedance of the components and cables preceding the circuit breaker from this total impedance yields the impedance of the short-circuited cable, allowing for a rough estimation of the location of the ground fault. This aids in accident analysis and fault location investigation. Simultaneously, utilizing the current and tripping information from each loop in the DC monitoring system, fault recording for differential fault trips can be performed similarly to high-voltage level fault recordings, which is beneficial for accident analysis, judgment, and the development of improvement measures.

[0049] (2) Comparison of calculated values ​​and simulated values The primary basis for differential coordination in DC circuits is the short-circuit current at each point, which is determined by impedance. Due to factors such as inconsistent manufacturing processes during circuit breaker production and measurement errors in cable laying lengths on-site, the calculated impedance always differs from the actual impedance. In DC power supply monitoring, since the current in the current transformer circuits at each stage of the circuit breaker is collected, the actual collected current can be compared with the calculated short-circuit current at that point to determine the accuracy of the differential simulation system results.

[0050] (3) Predefined long-term loop Due to incomplete cable and load circuit breaker information, differential calculations are generally not possible for long-term circuits. However, after differential simulation verification in DC monitoring, the calculation results of circuits with the same parameters can be used to limit the total circuit impedance according to the short-circuit current value that satisfies differential coordination. Since the rated values ​​of the circuit breakers on the end protection and control panel are all 3A or 4A, their impedance can be predefined. Therefore, the actual result provides a limited range for the impedance of the feeder cable. Cable impedance depends on cross-section and length. Since the cross-section of the end power supply cable is generally consistent with the type of load, it can also be predetermined. Therefore, the final result reflects the limitation of the cable length range. Through the above assumptions and reverse calculations, the cable length (n1~n2) meters that satisfies the differential coordination limitation can be displayed at the standby circuit. During expansion, the circuit breaker circuit to be used is selected according to the distance to the load power supply, thus avoiding the need to recalculate the differential for the expansion circuit.

[0051] This invention enhances the monitoring of power supply cables and load circuit breakers within the station's DC power supply monitoring system, enabling full-circuit monitoring. Based on this, it calculates, simulates, and verifies DC differential coordination. Without adding hardware, it effectively solves the problem that DC differential coordination can only be verified through calculations and on-site tests, making effective operational monitoring and simulation impossible.

[0052] Compared to designing solely through calculations and conducting on-site tests, this solution establishes a full-loop model within the monitoring interface. This model visually displays the impedance and current values ​​of each node and compares them with the actual measured values ​​of the circuit breaker and small current transformer (CT), verifying the accuracy of the calculation results. The differential coordination information can be accessed at any time, and DC faults can be analyzed and investigated during monitoring. This approach is of great significance for operation, maintenance, and expansion projects.

[0053] The main innovations are: (1) Use the existing DC monitoring module to realize the on-site simulation verification of differential coordination, and realize dynamic and real-time judgment.

[0054] (2) Establish a full-loop model and a differential judgment rule for different loop characteristics, and use control words to achieve differential fault tolerance.

[0055] (3) Implement advanced application functions such as fault waveform analysis, calculation comparison, and pre-definition of long-term circuits on the differential simulation verification differential.

[0056] The correct selection of protection devices for DC power supply systems is fundamental to the reliable operation of substation power supply systems. With increasing emphasis on the coordination of DC protection device differentials, the issue of how to verify and manage DC differentials at each stage of construction and operation is becoming increasingly prominent. The improved solution utilizes a power supply monitoring module—an operational device—for differential calculation and verification. Compared to the traditional method of using design calculation sheets and debugging instruments, this approach provides a direct and real-time display of the entire circuit impedance and current, automatically calculates and verifies the accuracy of the selection results, and allows for readily accessible differential coordination information. Furthermore, it enables the analysis and troubleshooting of DC faults during monitoring, which is of significant importance for operation, maintenance, and expansion / renovation.

[0057] This patent is based on expanding the software functionality of existing equipment within the station. Its model building and calculation methods are universal, requiring only the addition of a calculation module to the DC monitoring equipment and improvement of the display interface, incorporating cable information from design and construction drawings. The technical difficulty is manageable and feasible. The solution is applicable to all substations with multi-level DC power supply systems; the more complex the DC system, the more significant the effect, demonstrating broad application prospects.

[0058] This patent expands the functionality of existing equipment, and the model and calculation method are universal. The only repetitive task at each station is parameter input, with an additional investment of no more than 5,000 yuan per station. Adopting this optimized scheme can effectively reduce the escalation of accidents caused by improper DC differential coordination and power loss of the substation busbar. Considering a DC substation busbar connected to the protection and control equipment of 10 lines, if a fault occurs in the DC feeder of the protection and control equipment of one line, and the accident escalates, nine lines may be shut down due to protection failure, resulting in losses of hundreds of thousands of yuan and impacting system stability. Considering 10 220kV and above substations in a prefecture-level city (110kV generally does not use tiered power supply), an investment of 50,000 yuan can prevent the above-mentioned accidents from occurring within the operating cycle, demonstrating significant benefits.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A differential dynamic simulation verification system based on an integrated power supply DC monitoring module, characterized in that, Includes the following steps: Step 1: Establish the algorithm and full-loop display model for differential verification of the DC power supply system in the substation: Step 2: Based on the DC monitoring module of the integrated power system in the station, add DC feeder cable and load information to extend the DC monitoring range to the complete circuit; add circuit breaker internal resistance and tripping characteristic parameters, substitute them into the algorithm and circuit model, so that the DC monitoring module has the function of calculating and verifying the differential of each circuit. In step one, based on the two structures adopted in the project, namely the main screen hybrid power supply and the main sub-screen multi-level power supply, algorithms for differential verification of the DC power supply system of the substation and full-circuit display models are established respectively. In the main screen hybrid power supply model, there is a battery (C), which is connected to the battery outlet appliance (S1) via a battery cable (L1). Then, the first feeder cable (L2) from the feeder panel to the load (F) is connected via the DC main screen feeder circuit breaker (S2). Finally, it is connected to the load (F) via the DC sub-screen feeder circuit breaker (S3). The short-circuit current is calculated from four locations: the top of the battery outlet appliance (S1), the beginning and end of the DC main screen feeder circuit breaker (S2) outlet cable, and the outlet of the DC sub-screen feeder circuit breaker (S3). This short-circuit current is compared with the tripping current of the upper-level and upper-upper-level circuit breakers to examine their operating characteristics. In the main screen-sub-screen multi-level power supply model, there is a battery (C). The battery (C) is connected to the battery outlet appliance (S1) via the battery cable (L1). Then, the first feeder cable (L2) is connected to the load (F) via the DC main screen feeder circuit breaker (S2). The first feeder cable (L2) is connected to the second feeder cable (L3) via the DC sub-screen feeder circuit breaker (S3). The second feeder cable (L3) is connected to the load (F) via the load screen feeder circuit breaker (S4). The short-circuit current is calculated from six locations: the upper port of the DC main screen feeder circuit breaker (S2) and the beginning and end of its outlet cable, the beginning and end of the DC sub-screen feeder circuit breaker (S3) outlet cable, and the lower port of the load screen feeder circuit breaker. This short-circuit current is compared with the tripping current of the upper-level and upper-upper-level circuit breakers to examine its operating characteristics. Establish differential judgment rules for different circuit characteristics: when multiple different load devices are connected together and involve different functional types, differential coordination is fully realized; when a single load device occupies a DC circuit, if differential coordination is difficult to achieve, simultaneous tripping of the current level and the upper level is allowed; differential coordination verification of each circuit is realized through the control word of each circuit.

2. The differential dynamic simulation verification system based on an integrated power supply DC monitoring module according to claim 1, characterized in that: It also includes step three, which, based on the established full-loop display model, enables one or more of the following analyses: comparison of calculated and simulated values, pre-definition of long-term loops, and fault recording analysis.

3. The differential dynamic simulation verification system based on an integrated power supply DC monitoring module according to claim 2, characterized in that: Fault waveform analysis: When a circuit breaker in a certain circuit trips, the total impedance at the short circuit point is calculated based on the detected tripping current. The impedance of the components and cables before the circuit breaker is subtracted from the total impedance to obtain the impedance value of the short-circuited cable, thereby determining the location of the ground fault.

4. The differential dynamic simulation verification system based on an integrated power supply DC monitoring module according to claim 2, characterized in that: Comparison and analysis of calculated and simulated values: Collect the current of the current transformer circuit at each stage of the circuit breaker, compare the actual collected current with the calculated value of the short-circuit current at that point, and judge the accuracy of the results of the differential simulation system.

5. The differential dynamic simulation verification system based on an integrated power supply DC monitoring module according to claim 2, characterized in that: Long-term loop pre-definition: Using the calculation results of loops with the same parameters, the total loop impedance is limited according to the short-circuit current value that satisfies the differential coordination, and the range of cable length values ​​is calculated.

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