Safety verification method and system for power outage maintenance of power transmission and transformation equipment below 220 kV

Abstract

The present invention discloses a method and system for safety verification of power outage maintenance of power transmission and transformation equipment below 220 kV, and belongs to the technical field of safety verification of power system dispatching plan. The present invention obtains the real-time power grid topology map, the information of the first-level important users, the second-level important users, the power supply guarantee users and all the power outage maintenance orders to be dispatched and executed; based on all the power outage maintenance orders to be dispatched and executed, the load transfer scheme of the power outage maintenance orders to be dispatched and executed is generated; then according to the load transfer scheme of the power outage maintenance orders to be dispatched and executed, the future maintenance state power grid topology map is generated; then based on the future maintenance state power grid topology map, the power outage maintenance orders to be dispatched and executed are sequentially verified without power outage, without overload, without risk increase and with power supply guarantee, and finally the verification of all the power outage maintenance orders to be dispatched and executed is completed. The present invention is used for safety verification of the whole process of power outage maintenance scheduling of power transmission and transformation equipment below 220 kV.

Description

Technical Field

[0001] A method and system for safety verification of power outage maintenance of power transmission and transformation equipment below 220 kV are used for safety verification of the entire process of power outage maintenance scheduling of power transmission and transformation equipment below 220 kV, belonging to the technical field of safety verification of power system scheduling plan. Background Art

[0002] The formulation of the maintenance plan for power transmission and transformation equipment is a necessary measure to improve the reliability of power system equipment and components. However, an unreasonable power outage maintenance plan may cause power outages for users, overload of power lines and transformers, and affect the safe and stable operation of the power grid. At the same time, the load transfer plan is also an important part of the power outage maintenance plan for power grid equipment. If load transfer is not considered, power outage maintenance will cause power outages for a large number of users, seriously affecting the electricity business environment. In addition, in order to accurately analyze the power supply reliability of the load, it is necessary to understand the entire power supply path of the load and analyze the operation mode and operation status of the key facilities on the power supply path. Therefore, before implementing a specific maintenance plan, it is necessary to conduct a safety check on the maintenance plan, that is, to calculate the system flow based on the equipment power outage information and the power grid operation mode to determine whether the power grid is operating safely.

[0003] At present, the formulation of load transfer schemes is mainly based on manual experience, and the number of power outage users is minimized under the premise of ensuring the reliability of power supply for important users. At the same time, the identification of the load power supply path is mainly based on manual experience and ledger data. However, in actual production, the work level of personnel varies greatly, and the accuracy and timeliness of the ledger data are difficult to guarantee. In addition, the safety verification of the power outage maintenance plan of the transmission and transformation equipment is generally carried out by the dispatching and operation personnel according to the relevant provisions of the power grid operation, using tools such as PSASP to perform flow analysis and safety analysis on certain power outage maintenance plans. With the rapid development of my country's power grid construction, the scale of the power grid continues to expand, the workload of equipment commissioning and equipment transformation has greatly increased, the power grid structure and flow mode have changed greatly, and the safety and stability characteristics have changed rapidly. The use of manual methods to formulate the load transfer scheme for the maintenance plan, identify the load power supply path, and verify the safety of the maintenance plan can no longer adapt to the current development situation of the power grid, exposing the disadvantages of large workload, low efficiency, and low reliability. At present, there are few studies on the safety verification of maintenance plans for power transmission and transformation equipment. Existing studies mainly conduct safety verification from the aspects of average power outage time, power outage frequency, maintenance time, node voltage, line flow and maintenance resources. None of them considers the impact of maintenance plans on the power supply reliability of power supply users and important users, and cannot meet the requirements of the safety verification function of maintenance plans under the power supply conditions of power supply users and important users. At the same time, for the verification of multiple maintenance plans in the future, it is necessary to consider the implementation time of maintenance plans and changes in power grid topology. However, the existing maintenance plan verification method only considers the verification of a single maintenance plan on the real-time power grid topology, which cannot meet the needs of verifying multiple maintenance plans.

[0004] In summary, the existing verification methods have the following technical problems:

[0005] 1. When power supply is required to the guaranteed power supply users and important users, the maintenance plan is not safety checked, which may affect the reliability of the guaranteed power supply and the power supply to important users during the maintenance process;

[0006] 2. Only a single maintenance plan on the real-time power grid topology can be verified, without considering the time relationship of the maintenance plan and the changes to the power grid topology after the plan is implemented, resulting in inaccurate verification results when verifying multiple subsequent maintenance plans.

[0007] 3. The manual method of formulating load transfer plans for maintenance plans and identifying load power supply paths cannot adapt to the current development situation of the power grid, and has disadvantages such as large workload, low efficiency, and low reliability. Summary of the invention

[0008] The purpose of the present invention is to provide a method and system for safety verification of the entire process of power outage maintenance scheduling for power transmission and transformation equipment below 220 kV, so as to solve the problem that in the prior art, when power supply to power users and important users needs to be guaranteed, the maintenance plan is not safety verified, which may easily affect the reliability of power supply and power supply to important users during the maintenance process.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A method for power outage maintenance safety verification of power transmission and transformation equipment below 220 kV, comprising the following steps:

[0011] Step 1, read the real-time power grid topology map in the power system D5000, and read the information of the primary important users of the dual power sources, the secondary important users of the dual power sources and the guaranteed power supply users in the SG186 system, wherein the primary important users and the secondary important users are given users with high requirements for power supply reliability, and the guaranteed power supply users include the primary guaranteed power supply users, the secondary guaranteed power supply users and the tertiary guaranteed power supply users;

[0012] Step 2: Obtain all power outage maintenance orders to be scheduled for execution, wherein the information of the power outage maintenance orders to be scheduled for execution includes the power outage time and the power outage scope;

[0013] Step 3: Based on the order of the power outage times of the power outage maintenance orders to be dispatched and executed, determine the power outage maintenance order to be dispatched and executed that should be checked, and then generate the load transfer plan of the power outage maintenance order based on the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be dispatched and executed that has been checked and passed;

[0014] Step 4: Generate a future maintenance state power grid topology diagram based on the load transfer plan of the current power outage maintenance order to be dispatched and executed;

[0015] Step 5: Based on the information of primary important users, secondary important users, and power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance order to be dispatched for execution is sequentially checked for no power outage, no overload, no risk increase, and power supply guarantee. If any step fails, a failure message is fed back. Otherwise, the process switches to step 6.

[0016] Step 6: Determine whether all power outage maintenance orders to be scheduled for execution have been verified. If so, feedback the verification results. If not, go to step 3 and continue to verify the next power outage maintenance order to be scheduled for execution.

[0017] Further, the specific steps of step 3 are:

[0018] Step 3.1, based on the order of the power outage times of each power outage maintenance order to be scheduled and executed, determine the power outage maintenance order to be scheduled and executed that should be checked at present, and then based on all the power outage maintenance orders to be scheduled and executed, perform a union processing on the power outage times of the power outage maintenance orders to be scheduled and executed that overlap in power outage time and power outage range, and obtain the final power outage time of each power outage maintenance order to be scheduled and executed after the union processing, and finally, based on the final power outage time and power outage range, disconnect the corresponding switches and circuit breakers of the power outage equipment involved in the current power outage maintenance order to be scheduled and executed in the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be scheduled and executed that has been checked and executed, and obtain an updated power grid topology map;

[0019] Step 3.2: Check the power-off devices based on the updated power grid topology map to obtain all the 10kV busbars that have lost power, and record them as points to be restored;

[0020] Step 3.3, starting from each switch of the de-energized 10kV busbar, pre-search is performed, and the search paths that do not meet the conditions are feasibility pruned, where the search paths that do not meet the conditions are the paths that require load transfer connected to a dead island, the paths that require load transfer have inoperable equipment, or the branch flow on the load transfer path must exceed the limit after load transfer;

[0021] Step 3.4: Start from the switches of the de-energized 10kV busbar and conduct a deep search until the energized equipment is found;

[0022] Step 3.5: Taking the live equipment as the starting point, search for the 220kV busbar, that is, search for the power supply path to form a complete power supply path. After the power supply path search is completed, all load transfer plans are obtained.

[0023] Further, the specific steps of step 4 are:

[0024] According to the load transfer plan, close the corresponding switches and switches on the load transfer path of the updated power grid topology to obtain the load transfer path consistent with the actual topology. Figure 1 The future maintenance state power grid topology map is a modification made on the updated power grid topology map assuming that the power outage maintenance order has been scheduled for execution when the power outage maintenance order has not yet been scheduled for execution.

[0025] Further, the specific steps of step 5 are:

[0026] Step 5.1: Based on the future maintenance state power grid topology, the power outage maintenance order to be dispatched is checked without power outage. If the check fails, the information of the check failure is fed back. If the check passes, go to step 5.2.

[0027] Step 5.2: Based on the future maintenance state power grid topology diagram, the power outage maintenance order to be dispatched is checked for overload. If the check fails, feedback is given on the failure of the check. If the check passes, go to step 5.3.

[0028] Step 5.3: Based on the information of primary important users, secondary important users, power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance order to be dispatched is checked for no risk increase. If the check fails, feedback is given on the check failure. If the check passes, go to step 5.4.

[0029] Step 5.4: Based on the information of first-level important users, second-level important users, power supply guarantee users and the future maintenance state power grid topology map, the power supply guarantee verification is performed on the power outage maintenance order to be dispatched and executed. If the verification fails, the verification failure information is fed back; otherwise, the power outage maintenance order is verified to pass.

[0030] Further, the specific steps of step 5.1 are:

[0031] Step 5.11, read the real-time grid topology diagram of the power outage maintenance order to be dispatched or the grid topology diagram of the last verified power outage maintenance order to be dispatched, calculate the power flow using the PQ decomposition method, and obtain the power of each device in the real-time grid topology diagram or the grid topology diagram of the last verified power outage maintenance order to be dispatched;

[0032] Step 5.12, based on the future maintenance state grid topology of the power outage maintenance order to be dispatched, the PQ decomposition method is used to calculate the power flow to obtain the power of each device in the future maintenance state grid topology;

[0033] Step 5.13: Based on the two power flow calculation results, compare the two calculation results to determine whether there is any new power outage equipment, and determine whether it meets the constraints of the non-power outage verification strategy according to whether there is any new power outage equipment to obtain the verification result, and then make a judgment based on the verification result. If the verification fails, feedback the verification failure information, and if the verification passes, go to step 5.2;

[0034] The non-power outage verification strategy is: when a power outage is planned for equipment above 10kV bus, the power outage and maintenance load to be executed by the dispatcher will not cause power outage to users or stations after the power outage and maintenance load is transferred, that is, the status quo is maintained; or when a power outage is planned for 10kV bus and 10kV distribution lines, the power outage and maintenance load to be executed by the dispatcher will not cause power outage to the first-level important users of dual power sources and the second-level important users of dual power sources after the power outage and maintenance load is transferred.

[0035] Further, the specific steps of step 5.2 are:

[0036] Read the future maintenance state grid topology of the power outage maintenance order to be dispatched and executed, calculate the power flow using the PQ decomposition method, and obtain the load rate of each device in the future maintenance state grid topology. According to the power flow calculation result, determine whether it meets the constraint of the non-overload verification strategy to obtain the verification result, and then make a judgment based on the verification result. If the verification fails, feedback the verification failure information. If the verification passes, go to step 5.3;

[0037] The non-overload verification strategy is: after the power outage maintenance load is transferred to be executed by the dispatcher, no equipment will be overloaded, that is, the maximum predicted power of a certain equipment during the power outage will not exceed 90% of its allowable limit; or when the dispatcher performs a switching operation, the power supply mode is adjusted after the operation, which will not cause any equipment to be overloaded, that is, the equipment does not exceed its allowable limit.

[0038] Further, the step 5.3 adopts a power supply path search strategy to obtain the power supply paths of important users and power supply users based on the future maintenance state power grid topology map, the information of primary important users, secondary important users and power supply guarantee users, and detects whether the power supply paths of important users and power supply guarantee users have a single power source, a single bus or a single main transformer added to the user power supply path due to the implementation of the maintenance plan. The specific implementation process is:

[0039] 5.31、Set the future maintenance state of the power outage maintenance order to be dispatched and executed. Each node in the power grid topology diagram has a set of attribute values ​​(d j ,φ j , r j ), where d j represents the absolute value of the impedance modulus on the shortest power supply path from node n to node j of the 10kV feeder; φ j represents the previous node of the shortest power supply path from node n to node j of the 10kV feeder; r j is a 0,1 variable, r j =0 means node j is not marked, r j =1 indicates that node j has been marked. Node refers to any equipment node in the future maintenance state power grid topology diagram, including 220kV voltage level transformer nodes and 10kV feeder nodes. n refers to any 10kV feeder node.

[0040] 5.32. Initialization: The power grid has M 220kV voltage level transformer nodes, L guaranteed power supply users and important users, and each guaranteed power supply user and important user has N upstream power supply paths. l corresponding 10kV feeder nodes, n l Indicates the 10kV feeder node corresponding to the upper power supply path of the lth guaranteed power supply user and important user, initialize l = 1, n l =1, l = 1, 2, 3...L, n l=1,2,3,...N l , establish the power grid distance matrix A, where the matrix element a i,j There are several cases of assignment: when i=j, a i,j =0; when i≠j and there is an electrical connection between nodes i and j, element a i,j represents the absolute value of the impedance modulus between nodes i and j; when i≠j and there is no electrical connection A between nodes i and j, then a i,j =∞;

[0041] 5.33. Take out the 10kV feeder node n in the grid distance matrix A separately l The row where you are located gets A nl , set 10kV feeder node n l The attribute value d j =0,φ j =null,r j =1, 220kV voltage level transformer node d j =∞,φ j =null,r j =0;

[0042] 5.34. Update distance value d j Based on step 5.33, the following formula is used to calculate the absolute value of the impedance modulus from all marked nodes k to the unmarked nodes j directly connected to them:

[0043]

[0044] In the formula, R l,j is the resistance value between nodes k and j, X i,j is the reactance value between nodes k and j;

[0045] 5.35. Update node tag value r j , select d from all unlabeled nodes j The node s with the smallest value is marked, and its mark value is updated. s =1;

[0046] 5.36 Update φ j , select the marked parent node k of node s, that is, k is the 10kV feeder node n l The previous node of the shortest path to node s, let φ j = k;

[0047] 5.37. Determine whether all 220kV transformer nodes are marked. If they are marked, proceed to the next step. Otherwise, it means that this round of update is not completed, and go to step 5.34 to continue updating.

[0048] 5.38, if nl ≥N l , then proceed to the next step; otherwise, n l =n l +1 as the initial value, regenerate the power grid distance matrix A, and then go to step 5.33;

[0049] 5.39. If l ≥ L, then output the equipment data of all important users and guaranteed power supply users on the power supply path. The equipment data refers to the power supply path with a distance not equal to ∞ that is screened out, and according to φ j All devices on the entire power supply path obtained by the value; otherwise, let l=l+1, n l =1, regenerate the power grid distance matrix A, and go to step 5.33;

[0050] 5.40. Determine whether the equipment data obtained on the power supply path of all important users and guaranteed power supply users meet the constraints of the non-risk verification strategy to obtain the verification results, and then make a judgment based on the verification results. If the verification fails, feedback the verification failure information. If the verification passes, go to step 5.4;

[0051] The strategy for not increasing risk is: after the load of a single power outage for maintenance to be scheduled is transferred, the power supply reliability of the first-level important users and second-level important users with dual power supply will not be further reduced. That is, if a power outage plan has been arranged and caused one power supply to be cut off, the power supply path of the other power supply must not have a single power supply, a single bus or a single main transformer due to planned maintenance, and power outages for equipment that increase the risk of equipment overload and seriously reduce power supply reliability should not be arranged. In other words, users with multiple lines or main transformers cannot have multiple devices powered by power outages for maintenance at the same time, resulting in only one line or one main transformer remaining for power supply.

[0052] Further, the specific steps of step 5.4 are: judging whether the power supply paths of all important users and guaranteed power supply users meet the verification strategies of guaranteed power supply users of different levels to obtain verification results, and then judging according to the verification results. If the verification fails, feedback is given on the verification failure information; if the verification passes, the verification result of the power outage maintenance order to be dispatched and executed is obtained;

[0053] The verification strategy for different levels of power supply users is as follows: for first-level power supply users, no planned power outages will be arranged for the 10kV power supply lines, transferable lines and power supply equipment of voltage levels above the power supply users during the power supply guarantee period; for second-level power supply users, no planned power outages will be arranged for the 10kV power supply lines and transferable lines of the power supply users during the power supply guarantee period; for third-level power supply users, no planned power outages will be arranged for the 10kV power supply lines of the power supply users during the power supply guarantee period; under normal operating conditions, the two power supplies for power supply users of different levels cannot come from the same 220 kV substation.

[0054] A power outage maintenance safety verification system for power transmission and transformation equipment below 220 kV, comprising:

[0055] Information acquisition module: reads the real-time power grid topology map in the power system D5000, reads the information of the first-level important users of dual power sources, the second-level important users of dual power sources and the guaranteed power supply users in the SG186 system, wherein the first-level important users and the second-level important users are given users with high requirements for power supply reliability, and the guaranteed power supply users include the first-level guaranteed power supply users, the second-level guaranteed power supply users and the third-level guaranteed power supply users, and obtains all power outage maintenance orders to be dispatched and executed, wherein the information of the power outage maintenance orders to be dispatched and executed includes the power outage time and the power outage range;

[0056] Load transfer plan generation module: Based on the order of power outage times of each power outage maintenance order to be dispatched and executed, determine the power outage maintenance order to be checked at present, and then generate the load transfer plan of the power outage maintenance order based on the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be dispatched and executed that has been checked and passed;

[0057] Future maintenance state power grid topology map generation module: Generates the future maintenance state power grid topology map according to the load transfer plan of the current power outage maintenance order to be dispatched and executed;

[0058] Verification module: Based on the information of first-level important users, second-level important users, power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance orders to be dispatched and executed are verified in turn for no power outage verification, no overload verification, no risk increase verification and power supply guarantee verification. If any step of the verification fails, the failure information is fed back. Otherwise, it is determined whether all the power outage maintenance orders to be dispatched and executed have been verified. If so, the verification results are fed back. If not, the module goes to the load transfer plan generation module to continue to verify the next power outage maintenance order to be dispatched and executed.

[0059] Furthermore, the specific implementation steps of the load transfer scheme generation module are:

[0060] Step 3.1, based on the order of the power outage times of each power outage maintenance order to be scheduled and executed, determine the power outage maintenance order to be scheduled and executed that should be checked at present, and then based on all the power outage maintenance orders to be scheduled and executed, perform a union processing on the power outage times of the power outage maintenance orders to be scheduled and executed that overlap in power outage time and power outage range, and obtain the final power outage time of each power outage maintenance order to be scheduled and executed after the union processing, and finally, based on the final power outage time and power outage range, disconnect the corresponding switches and circuit breakers of the power outage equipment involved in the current power outage maintenance order to be scheduled and executed in the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be scheduled and executed that has been checked and executed, and obtain an updated power grid topology map;

[0061] Step 3.2: Check the power-off devices based on the updated power grid topology map to obtain all the 10kV busbars that have lost power, and record them as points to be restored;

[0062] Step 3.3, starting from each switch of the de-energized 10kV busbar, pre-search is performed, and the search paths that do not meet the conditions are feasibility pruned, where the search paths that do not meet the conditions are the paths that require load transfer connected to a dead island, the paths that require load transfer have inoperable equipment, or the branch flow on the load transfer path must exceed the limit after load transfer;

[0063] Step 3.4: Start from the switches of the de-energized 10kV busbar and conduct a deep search until the energized equipment is found;

[0064] Step 3.5: Taking the live equipment as the starting point, search for the 220kV busbar, that is, search for the power supply path to form a complete power supply path. After the power supply path search is completed, all load transfer plans are obtained.

[0065] The specific implementation steps of the future maintenance state power grid topology map generation module are:

[0066] According to the load transfer plan, close the corresponding switches and switches on the load transfer path of the updated power grid topology to obtain the load transfer path consistent with the actual topology. Figure 1 The future maintenance state power grid topology map is a modification made on the updated power grid topology map assuming that the power outage maintenance order has been scheduled and executed before it is scheduled and executed;

[0067] The specific implementation steps of the verification module are:

[0068] Step 5.1: Based on the future maintenance state power grid topology, the power outage maintenance order to be dispatched is checked without power outage. If the check fails, the information of the check failure is fed back. If the check passes, go to step 5.2.

[0069] Step 5.2: Based on the future maintenance state power grid topology diagram, the power outage maintenance order to be dispatched is checked for overload. If the check fails, feedback is given on the failure of the check. If the check passes, go to step 5.3.

[0070] Step 5.3: Based on the information of primary important users, secondary important users, power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance order to be dispatched is checked for no risk increase. If the check fails, feedback is given on the check failure. If the check passes, go to step 5.4.

[0071] Step 5.4: Based on the information of first-level important users, second-level important users, power supply guarantee users and the future maintenance state power grid topology diagram, the power supply guarantee verification is performed on the power outage maintenance order to be dispatched and executed. If the verification fails, the verification failure information is fed back. Otherwise, the power outage maintenance order is verified and it is determined whether all power outage maintenance orders to be dispatched and executed have been verified. If so, the verification result is fed back. If not, go to the load transfer plan generation module to continue to verify the next power outage maintenance order.

[0072] Compared with the prior art, the advantages of the present invention are:

[0073] 1. When it is necessary to supply power to the guaranteed power supply users and important users, the present invention sequentially performs non-power outage verification, overload verification, no risk increase verification and guaranteed power supply verification on the maintenance plan (power outage maintenance order), thereby realizing the safety verification of the power outage maintenance order, that is, comprehensively considering the impact of the power outage maintenance plan on the reliability and stability of the power supply of the power grid, and providing the dispatcher with a more comprehensive and reliable safety verification result, thereby ensuring the reliability of the guaranteed power supply and the power supply to important users during the maintenance process;

[0074] Second, the present invention can not only verify a single maintenance plan on the real-time power grid topology map, but also verify multiple maintenance plans, that is, it takes into account the time relationship of the maintenance plan and the changes to the power grid topology map after the plan is implemented, and can realize accurate verification when verifying multiple subsequent maintenance plans, so as to achieve the purpose of early verification;

[0075] Third, the present invention can verify multiple future maintenance plans, that is, it can iteratively generate the future maintenance state power grid topology according to the maintenance plan, and perform safety verification under the influence of the previous round of maintenance plan (that is, each verification is to modify the power grid topology map based on the maintenance plan (power outage maintenance order) that has been successfully verified or is being verified, and the modification process is superimposed) on the power grid topology map;

[0076] Fourth, the present invention adopts a feasibility pruning method to remove infeasible paths and solutions during the search process, thereby reducing the number of traversals, reducing complexity, and shortening calculation time. When the number of solutions is too large, the amount of calculation can be reduced by more than 90%;

[0077] 5. The present invention proposes an automatic identification strategy for load power supply paths (i.e., a non-risk verification strategy and a power supply guarantee verification strategy), uses the impedance value between power grid nodes to represent the distance between nodes, and identifies the power supply paths above the load 10kV feeder nodes through the idea of ​​iterative search, providing support for conducting user power supply reliability analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0079] Figure 1 A schematic diagram of the process of the invention;

[0080] Figure 2 It is a partial connection relationship in the power grid topology diagram in the embodiment of the present invention;

[0081] Figure 3 It is a partial connection relationship of the future maintenance state power grid topology diagram in the embodiment of the present invention. DETAILED DESCRIPTION

[0082] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0083] A method for power outage maintenance safety verification of power transmission and transformation equipment below 220 kV, comprising the following steps:

[0084] Step 1, read the real-time power grid topology map in the power system D5000, and read the information of the primary important users of the dual power supply, the secondary important users of the dual power supply, and the guaranteed power supply users in the SG186 system, wherein the primary important users and the secondary important users are given users with high requirements for power supply reliability, and the guaranteed power supply users are users who are not allowed to have power outages, including primary guaranteed power supply users, secondary guaranteed power supply users, and tertiary guaranteed power supply users;

[0085] Step 2: Obtain all power outage maintenance orders to be scheduled for execution, wherein the information of the power outage maintenance orders to be scheduled for execution includes the power outage time and the power outage scope;

[0086] Step 3: Based on the order of the power outage times of the power outage maintenance orders to be dispatched and executed, determine the power outage maintenance order to be dispatched and executed that should be checked, and then generate the load transfer plan of the power outage maintenance order based on the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be dispatched and executed that has been checked and passed;

[0087] The specific steps are:

[0088] Step 3.1, based on the order of the power outage times of each power outage maintenance order to be dispatched and executed, determine the power outage maintenance order to be dispatched and executed that should be checked at present, and then based on all the power outage maintenance orders to be dispatched and executed, the power outage times of the power outage maintenance orders to be dispatched and executed that overlap in power outage time and power outage range are combined and processed, and the final power outage time of each power outage maintenance order to be dispatched and executed is obtained after the combination processing. For example, power outage maintenance order A to be dispatched and executed and power outage maintenance order B to be dispatched and executed work at the same location, and power outage maintenance order A to be dispatched and executed is from 8:00 to 12:00, and power outage maintenance order B to be dispatched and executed is from 8:00 to 12:00. Power outage maintenance order B is from 7:00 to 11:00. After the union processing, the time of the two power outage maintenance orders to be scheduled is adjusted to 7:00-12:00. Finally, based on the final power outage time and power outage range, the power outage equipment involved in the current power outage maintenance order to be scheduled is disconnected in the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be scheduled that has been verified and passed (if there is no power outage maintenance order to be scheduled that has been verified and passed, it is processed on the basis of the real-time power grid topology map) to obtain an updated power grid topology map;

[0089] Step 3.2: Check the power-off devices based on the updated power grid topology map to obtain all the 10kV busbars that have lost power, and record them as points to be restored;

[0090] Step 3.3, starting from each switch of the de-energized 10kV busbar, pre-search is performed, and the search paths that do not meet the conditions are feasibility pruned, where the search paths that do not meet the conditions are the paths that require load transfer connected to a dead island, the paths that require load transfer have inoperable equipment, or the branch flow on the load transfer path must exceed the limit after load transfer;

[0091] Step 3.4: Start from the switches of the de-energized 10kV busbar and conduct a deep search until the energized equipment is found;

[0092] Step 3.5: Taking the live equipment as the starting point, search for the 220kV busbar, that is, search for the power supply path to form a complete power supply path. After the power supply path search is completed, all load transfer plans are obtained.

[0093] Step 4: Generate a future maintenance state power grid topology diagram based on the load transfer plan of the current power outage maintenance order to be dispatched and executed;

[0094] The specific steps are:

[0095] According to the load transfer plan, close the corresponding switches and switches on the load transfer path of the updated power grid topology to obtain the load transfer path consistent with the actual topology. Figure 1The future maintenance state grid topology map is the modification made on the updated grid topology map on the assumption that the power outage maintenance order has been scheduled for execution before it is scheduled for execution. The so-called real-time verification means that after the maintenance plan A (i.e., power outage maintenance order A) is verified based on the real-time grid topology map, the changes of maintenance plan A are not updated to the grid topology map, and the real-time grid topology map is continued to be used to verify maintenance plan B. This has disadvantages, because after maintenance plan A is executed, the entire grid topology map will change. Maintenance plan B should be verified with the changed grid topology map, and maintenance plan B should be verified with the grid topology map of the last verified power outage maintenance order to be scheduled for execution.

[0096] Step 5: Based on the future maintenance state power grid topology diagram, the power outage maintenance order to be dispatched is sequentially checked for no power outage, no overload, no risk increase, and power supply guarantee. If any step fails, a failure message is fed back. Otherwise, the process switches to step 6.

[0097] The specific steps are:

[0098] Step 5.1: Based on the future maintenance state power grid topology, the power outage maintenance order to be dispatched is checked without power outage. If the check fails, the information of the check failure is fed back. If the check passes, go to step 5.2.

[0099] The specific steps are:

[0100] Step 5.11, read the real-time grid topology diagram of the power outage maintenance order to be dispatched or the grid topology diagram of the last verified power outage maintenance order to be dispatched, calculate the power flow using the PQ decomposition method, and obtain the power of each device in the real-time grid topology diagram or the grid topology diagram of the last verified power outage maintenance order to be dispatched;

[0101] Step 5.12, based on the future maintenance state grid topology of the power outage maintenance order to be dispatched, the PQ decomposition method is used to calculate the power flow to obtain the power of each device in the future maintenance state grid topology;

[0102] Step 5.13: Based on the two power flow calculation results, compare the two calculation results to determine whether there is any new power outage equipment, and determine whether it meets the constraints of the non-power outage verification strategy according to whether there is any new power outage equipment to obtain the verification result, and then make a judgment based on the verification result. If the verification fails, feedback the verification failure information, and if the verification passes, go to step 5.2;

[0103] The non-power outage verification strategy is: when a power outage is planned for equipment above 10kV bus, the power outage and maintenance load to be executed by the dispatcher will not cause power outage to users or stations after the power outage and maintenance load is transferred, that is, the status quo is maintained; or when a power outage is planned for 10kV bus and 10kV distribution lines, the power outage and maintenance load to be executed by the dispatcher will not cause power outage to the first-level important users of dual power sources and the second-level important users of dual power sources after the power outage and maintenance load is transferred.

[0104] Step 5.2: Based on the future maintenance state power grid topology diagram, the power outage maintenance order to be dispatched is checked for overload. If the check fails, feedback is given on the failure of the check. If the check passes, go to step 5.3.

[0105] The specific steps are:

[0106] Read the future maintenance state grid topology of the power outage maintenance order to be dispatched and executed, calculate the power flow using the PQ decomposition method, and obtain the load rate of each device in the future maintenance state grid topology. According to the power flow calculation result, determine whether it meets the constraint of the non-overload verification strategy to obtain the verification result, and then make a judgment based on the verification result. If the verification fails, feedback the verification failure information. If the verification passes, go to step 5.3;

[0107] The non-overload verification strategy is: after the power outage maintenance load is transferred to be executed by the dispatcher, no equipment will be overloaded, that is, the maximum predicted power of a certain equipment during the power outage will not exceed 90% of its allowable limit; or when the dispatcher performs a switching operation, the power supply mode is adjusted after the operation, which will not cause any equipment to be overloaded, that is, the equipment does not exceed its allowable limit.

[0108] Step 5.3: Based on the information of the first-level important users, the second-level important users, the power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance order to be dispatched is checked for no risk increase. If the check fails, the information of the check failure is fed back. If the check passes, go to step 5.4; that is, based on the future maintenance state power grid topology map, the first-level important users, the second-level important users and the power supply guarantee users information, the power supply path search strategy is adopted to obtain the power supply path of the important users and the power supply guarantee users, and whether the power supply path of the important users and the power supply guarantee users has added a single power supply, a single bus or a single main transformer on the user power supply path due to the implementation of the maintenance plan. The specific implementation process is:

[0109] 5.31、Set the future maintenance state of the power outage maintenance order to be dispatched and executed. Each node in the power grid topology diagram has a set of attribute values ​​(d j ,φ j , r j ), where d j represents the absolute value of the impedance modulus on the shortest power supply path from node n to node j of the 10kV feeder; φ jrepresents the previous node of the shortest power supply path from node n to node j of the 10kV feeder; r j is a 0,1 variable, r j =0 means node j is not marked, r j =1 indicates that node j has been marked. Node refers to any equipment node in the future maintenance state power grid topology diagram, including 220kV voltage level transformer nodes and 10kV feeder nodes. n refers to any 10kV feeder node.

[0110] 5.32. Initialization: The power grid has M 220kV voltage level transformer nodes, L guaranteed power supply users and important users, and each guaranteed power supply user and important user has N upstream power supply paths. l corresponding 10kV feeder nodes, n l Indicates the 10kV feeder node corresponding to the upper power supply path of the lth guaranteed power supply user and important user, initialize l = 1, n l =1, l = 1, 2, 3...L, n l =1,2,3,...N l , establish the power grid distance matrix A, where the matrix element a i,j There are several cases of assignment: when i=j, a i,j =0; when i≠j and there is an electrical connection between nodes i and j, element a i,j represents the absolute value of the impedance modulus between nodes i and j; when i≠j and there is no electrical connection A between nodes i and j, then a i,j =∞;

[0111] 5.33. Take out the 10kV feeder node n in the grid distance matrix A separately l The row where you are located gets A nl , set 10kV feeder node n l The attribute value d j =0,φ j =null,r j =1, 220kV voltage level transformer node d j =∞,φ j =null,r j =0;

[0112] 5.34. Update distance value d j Based on step 5.33, the following formula is used to calculate the absolute value of the impedance modulus from all marked nodes k to the unmarked nodes j directly connected to them:

[0113]

[0114] In the formula, R l,j is the resistance value between nodes k and j, Xi,j is the reactance value between nodes k and j;

[0115] 5.35. Update node tag value r j , select d from all unlabeled nodes j The node s with the smallest value is marked, and its mark value is updated. s =1;

[0116] 5.36 Update φ j , select the marked parent node k of node s, that is, k is the 10kV feeder node n l The previous node of the shortest path to node s, let φ j = k;

[0117] 5.37. Determine whether all 220kV transformer nodes are marked. If they are marked, proceed to the next step. Otherwise, it means that this round of update is not completed, and go to step 5.34 to continue updating.

[0118] 5.38, if n l ≥N l , then proceed to the next step; otherwise, n l =n l +1 as the initial value, regenerate the power grid distance matrix A, and then go to step 5.33;

[0119] 5.39. If l ≥ L, then output the equipment data of all important users and guaranteed power supply users on the power supply path. The equipment data refers to the power supply path with a distance not equal to ∞ that is screened out, and according to φ j All devices on the entire power supply path obtained by the value; otherwise, let l=l+1, n l =1, regenerate the power grid distance matrix A, and go to step 5.33;

[0120] 5.40. Determine whether the equipment data obtained on the power supply path of all important users and guaranteed power supply users meet the constraints of the non-risk verification strategy to obtain the verification results, and then make a judgment based on the verification results. If the verification fails, feedback the verification failure information. If the verification passes, go to step 5.4;

[0121] The strategy for not increasing risk is: after the load of a single power outage for maintenance to be scheduled is transferred, the power supply reliability of the first-level important users and second-level important users with dual power supply will not be further reduced. That is, if a power outage plan has been arranged and caused one power supply to be cut off, the power supply path of the other power supply must not have a single power supply, a single bus or a single main transformer due to planned maintenance, and power outages for equipment that increase the risk of equipment overload and seriously reduce power supply reliability should not be arranged. In other words, users with multiple lines or main transformers cannot have multiple devices powered by power outages for maintenance at the same time, resulting in only one line or one main transformer remaining for power supply.

[0122] Step 5.4: Based on the information of first-level important users, second-level important users, power supply guarantee users and the future maintenance state power grid topology map, the power supply guarantee verification is performed on the power outage maintenance order to be dispatched and executed. If the verification fails, the verification failure information is fed back; otherwise, the power outage maintenance order is verified to pass.

[0123] The specific steps are:

[0124] Determine whether the equipment data on the power supply path of all important users and guaranteed power users (the same method and data obtained in step 5.40) meet the verification strategy of guaranteed power users of different levels to obtain the verification results, and then make a judgment based on the verification results. If the verification fails, feedback the verification failure information; if the verification passes, the verification result of the power outage maintenance order to be dispatched and executed is obtained;

[0125] The verification strategy for different levels of power supply users is as follows: for first-level power supply users, no planned power outages will be arranged for the 10kV power supply lines, transferable lines and power supply equipment of voltage levels above the power supply users during the power supply guarantee period; for second-level power supply users, no planned power outages will be arranged for the 10kV power supply lines and transferable lines of the power supply users during the power supply guarantee period; for third-level power supply users, no planned power outages will be arranged for the 10kV power supply lines of the power supply users during the power supply guarantee period; under normal operating conditions, the two power supplies for power supply users of different levels cannot come from the same 220 kV substation.

[0126] Step 6: Determine whether all power outage maintenance orders to be scheduled for execution have been verified. If so, feedback the verification results. If not, go to step 3 and continue to verify the next power outage maintenance order.

[0127] Example

[0128] 1.1 Case Overview

[0129] The method proposed in this paper is tested by taking a certain city’s high-voltage distribution network as an example. Figure 2As shown, for the convenience of representation, only part of the connection relationship in the power grid topology diagram is shown in the figure. There are two 220kV voltage level substations in the figure, 220kV Huanghe Station and 220kV Yangtze River Station; there are also two 110kV level substations, 110kV Huangshan Station and 110kV Taishan Station. Among them, the 911 and 912 loads of the 110kV Huangshan Station are powered by the 220kV Huanghe Station #1 transformer; the 911 and 912 loads of the 110kV Taishan Station are powered by the 220kV Yangtze River Station #1 transformer. The 914 switch of the 110kV Huangshan Station is under maintenance, and the secondary important user Volkswagen is in the power supply guarantee period. Its 10kV main power supply line is the 911 line of the 110kV Huangshan Station, and the backup power supply line is the 913 line of the 110kV Taishan Station. The high-voltage branch plans to overhaul the 911 line of the 110kV Huangshan Station, and uses the method proposed in this case to conduct a safety check on the maintenance plan. The power conditions of each 10kV large feeder are shown in Table 1, and the capacity and load rate of each transformer are shown in Table 2.

[0130] Table 1 Load power table

[0131] Line Name Active power(MW) Reactive power (MVAR) 110kV Huangshan Substation 911 2.5 0.4 110kV Huangshan Station 912 1.6 -0.3 110kV Huangshan Station 913 2.4 0.2 110kV Huangshan Substation 914 0 0 110kV Taishan Substation 911 3.7 0.8 110kV Taishan Station 912 0.9 -0.1 110kV Taishan Station 913 1.4 0.2 110kV Taishan Station 914 2.3 0.1

[0132] Table 2 Transformer load rate table

[0133]

[0134]

[0135] 1.2 Safety verification results

[0136] The 10kV main power supply line of Volkswagen, an important secondary user, is the 110kV Huangshan Station 911 line, and the backup power supply line is the 110kV Taishan Station 913 line. Under the current power grid topology (i.e., the real-time power grid topology network), the power supply path of Volkswagen is: 110kV Huangshan Station 911 line, 110kV Huangshan Station 10kV#1 bus, 110kV Huangshan Station #1 transformer, 110kV Huangshan Station 110kV#1 bus, 220kV Huanghe Station 110kV#1 bus, 220kV Huanghe Station #1 transformer. According to the maintenance order, the 110kV Huangshan Station 911 switch state is changed to the disconnected state, and the future maintenance state power grid topology is generated, such as Figure 3 Then, we will conduct the verification of no power outage, no overload, no risk increase and power supply guarantee respectively.

[0137] 1.2.1 Non-power-off verification results

[0138] The power flow calculation of the future power grid topology is performed, and the power of each 10kV feeder is shown in Table 3. From the results, it can be seen that when the 110kV Huangshan Station 911 switch state is disconnected, Volkswagen is powered by the original backup power supply line 110kV Taishan Station 913 line, and the original 110kV Huangshan Station 911 line load is also transferred to the 110kV Taishan Station 913. At the same time, due to the different distances of different power supply paths, the reactive power is not exactly the same, from the original 0.4MVAR to 0.3MVAR; the active power does not change much, still 2.5MW. In summary, there is no load power outage, and the non-power outage verification is passed.

[0139] Table 3 Load power table

[0140] Line Name Active power(MW) Reactive power (MVAR) 110kV Huangshan Substation 911 0 0 110kV Huangshan Station 912 1.6 -0.3 110kV Huangshan Station 913 2.4 0.2 110kV Huangshan Substation 914 0 0 110kV Taishan Substation 911 3.7 0.8 110kV Taishan Station 912 0.9 -0.1 110kV Taishan Station 913 3.9 0.5 110kV Taishan Station 914 2.3 0.1

[0141] 1.2.2 No overload verification results

[0142] The load flow calculation of the future power grid topology is performed, and the load rates of each transformer are shown in Table 4. All transformers are not overloaded, and the current carrying capacity of the 913 line of the 110kV Taishan Station is 227A, which is also lower than the rated current carrying capacity of the line 600A, so it passes the overload test.

[0143] Table 4 Transformer load table

[0144]

[0145] 1.2.3 No increase in risk verification results

[0146] When Volkswagen was powered by the original backup power supply line 110kV Taishan Station 913 line, the latest power supply path was obtained through the automatic power supply path identification method: 110kV Taishan Station 913 line, 110kV Taishan Station 10kV#1 bus, 110kV Taishan Station #2 transformer, 110kV Taishan Station 110kV#1 bus, 220kV Yangtze River Station 110kV#1 bus, 220kV Yangtze River Station #1 transformer. According to the non-increased risk verification strategy proposed in this case, Volkswagen, as a secondary user, did not have a single power supply, single bus or single main transformer in operation on the power supply path of the other power supply 110kV Taishan Station 913 after one of the power sources, namely 110kV Huangshan Station 911, was shut down for maintenance. At the same time, there was no situation where only one line or one main transformer was left for power supply. Therefore, the non-increased risk verification passed. 1.2.4 Power supply guarantee verification results

[0147] When Volkswagen was powered by the original backup power supply line 110kV Taishan Station 913 Line, the latest power supply path obtained by the automatic power supply path identification method was: 110kV Taishan Station 913 Line, 110kV Taishan Station 10kV#1 Bus, 110kV Taishan Station #2 Transformer, 110kV Taishan Station 110kV#1 Bus, 220kV Yangtze River Station 110kV#1 Bus, 220kV Yangtze River Station #1 Transformer. According to the power supply verification strategy proposed in this case, since Volkswagen is a second-level power supply user and is within the power supply time, its main power supply 110kV Huangshan Station 911 Line was shut down for maintenance. Since Volkswagen is a second-level power supply user, it does not meet the "second-level power supply user, the 10kV power supply line and the transferable supply line of the power supply user during the power supply time are not scheduled for power outages", so the power supply verification failed and the maintenance plan was cancelled.

Claims

1. A method for power outage maintenance safety verification of power transmission and transformation equipment below 220 kV, characterized in that: The steps include: Step 1, read the real-time power grid topology map in the power system D5000, and read the information of the first-level important users of dual power sources, the second-level important users of dual power sources and the guaranteed power supply users in the SG186 system, where the guaranteed power supply users include the first-level guaranteed power supply users, the second-level guaranteed power supply users and the third-level guaranteed power supply users; Step 2: Obtain all power outage maintenance orders to be scheduled for execution, wherein the information of the power outage maintenance orders to be scheduled for execution includes the power outage time and the power outage scope; Step 3: Based on the order of the power outage times of the power outage maintenance orders to be dispatched and executed, determine the power outage maintenance order to be dispatched and executed that should be checked, and then generate the load transfer plan of the power outage maintenance order based on the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be dispatched and executed that has been checked and passed; Step 4: Generate a future maintenance state power grid topology diagram based on the load transfer plan of the current power outage maintenance order to be dispatched and executed; Step 5: Based on the information of primary important users, secondary important users, and power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance order to be dispatched for execution is sequentially checked for no power outage, no overload, no risk increase, and power supply guarantee. If any step fails, a failure message is fed back. Otherwise, the process switches to step 6. Step 6: Determine whether all the power outage maintenance orders to be dispatched and executed have been verified. If so, feedback the verification results. If not, go to step 3 and continue to verify the next power outage maintenance order to be dispatched and executed; The specific steps of step 3 are: Step 3.1, based on the order of the power outage times of each power outage maintenance order to be scheduled and executed, determine the power outage maintenance order to be scheduled and executed that should be checked at present, and then based on all the power outage maintenance orders to be scheduled and executed, perform a union processing on the power outage times of the power outage maintenance orders to be scheduled and executed that overlap in power outage time and power outage range, and obtain the final power outage time of each power outage maintenance order to be scheduled and executed after the union processing, and finally, based on the final power outage time and power outage range, disconnect the corresponding switches and circuit breakers of the power outage equipment involved in the current power outage maintenance order to be scheduled and executed in the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be scheduled and executed that has been checked and executed, and obtain an updated power grid topology map; Step 3.2: Check the power-off devices based on the updated power grid topology map to obtain all the 10kV busbars that have lost power, and record them as points to be restored; Step 3.3, starting from each switch of the de-energized 10kV busbar, pre-search is performed, and the search paths that do not meet the conditions are feasibility pruned, where the search paths that do not meet the conditions are the paths that require load transfer connected to a dead island, the paths that require load transfer have inoperable equipment, or the branch flow on the load transfer path must exceed the limit after load transfer; Step 3.4: Start from the switches of the de-energized 10kV busbar and conduct a deep search until the energized equipment is found; Step 3.5, starting from the live equipment, search for the 220kV busbar, that is, search for the power supply path to form a complete power supply path. After the power supply path search is completed, all load transfer plans are obtained; The specific steps of step 4 are: According to the load transfer plan, the corresponding switches and circuit breakers on the load transfer path of the updated power grid topology are closed, and the future maintenance state power grid topology consistent with the actual topology is obtained, wherein the future maintenance state power grid topology refers to the modification made on the updated power grid topology when the power outage maintenance order has not been scheduled for execution, assuming that it has been scheduled for execution; The specific steps of step 5 are: Step 5.1: Based on the future maintenance state power grid topology, the power outage maintenance order to be dispatched is checked without power outage. If the check fails, the information of the check failure is fed back. If the check passes, go to step 5.

2. Step 5.2: Based on the future maintenance state power grid topology diagram, the power outage maintenance order to be dispatched is checked for overload. If the check fails, feedback is given on the failure of the check. If the check passes, go to step 5.

3. Step 5.3: Based on the information of primary important users, secondary important users, power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance order to be dispatched is checked for no risk increase. If the check fails, feedback is given on the check failure. If the check passes, go to step 5.

4. Step 5.4: Based on the information of the primary important users, the secondary important users, the power supply guarantee users and the future maintenance state power grid topology diagram, the power supply guarantee check is performed on the power outage maintenance order to be dispatched and executed. If the check fails, the check failure information is fed back. Otherwise, the power outage maintenance order passes the check; The specific steps of step 5.1 are: Step 5.11, read the real-time grid topology diagram of the power outage maintenance order to be dispatched or the grid topology diagram of the last verified power outage maintenance order to be dispatched, calculate the power flow using the PQ decomposition method, and obtain the power of each device in the real-time grid topology diagram or the grid topology diagram of the last verified power outage maintenance order to be dispatched; Step 5.12, based on the future maintenance state grid topology of the power outage maintenance order to be dispatched, the PQ decomposition method is used to calculate the power flow to obtain the power of each device in the future maintenance state grid topology; Step 5.13: Based on the two power flow calculation results, compare the two calculation results to determine whether there is any new power outage equipment, and determine whether it meets the constraints of the non-power outage verification strategy according to whether there is any new power outage equipment to obtain the verification result, and then make a judgment based on the verification result. If the verification fails, feedback the verification failure information, and if the verification passes, go to step 5.2; The non-power outage verification strategy is: when the power outage plan for equipment above 10kV bus is implemented, after the power outage and maintenance load of the power outage and maintenance order to be executed by the dispatcher is transferred, it will not cause power outage to users or stations, that is, maintain the status quo; or when the power outage plan for 10kV bus and 10kV distribution line is implemented, after the power outage and maintenance load of the power outage and maintenance order to be executed by the dispatcher is transferred, it will not cause power outage to the first-level important users of dual power sources and the second-level important users of dual power sources; The specific steps of step 5.2 are: Read the future maintenance state grid topology of the power outage maintenance order to be dispatched and executed, calculate the power flow using the PQ decomposition method, and obtain the load rate of each device in the future maintenance state grid topology. According to the power flow calculation result, determine whether it meets the constraint of the non-overload verification strategy to obtain the verification result, and then make a judgment based on the verification result. If the verification fails, feedback the verification failure information. If the verification passes, go to step 5.3; The overload verification strategy is: after the power outage maintenance load is transferred to the power outage maintenance order to be executed by the dispatcher, no equipment will be overloaded, that is, the maximum predicted power of a certain equipment during the power outage will not exceed 90% of its allowable limit; or when the dispatcher performs a switching operation, the power supply mode adjustment after the operation will not cause any equipment to be overloaded, that is, the equipment does not exceed its allowable limit; The step 5.3 adopts a power supply path search strategy to obtain the power supply paths of important users and power supply users based on the future maintenance state power grid topology map, the information of primary important users, secondary important users and power supply guarantee users, and detects whether the power supply paths of important users and power supply guarantee users have added a single power source, a single bus or a single main transformer in the user power supply path due to the implementation of the maintenance plan. The specific implementation process is as follows: 5.31、Set the future maintenance state of the power outage maintenance order to be dispatched and executed. Each node in the power grid topology diagram has a set of attribute values ​​(d j ,φ j , r j ), where d j represents the absolute value of the impedance modulus on the shortest power supply path from node n to node j of the 10kV feeder; φ j represents the previous node of the shortest power supply path from node n to node j of the 10kV feeder; r j is a 0,1 variable, r j =0 means node j is not marked, r j =1 indicates that node j has been marked. Node refers to any equipment node in the future maintenance state power grid topology diagram, including 220kV voltage level transformer nodes and 10kV feeder nodes. n refers to any 10kV feeder node. 5.

32. Initialization: The power grid has M 220kV voltage level transformer nodes, L guaranteed power supply users and important users, and each guaranteed power supply user and important user has N upstream power supply paths. l corresponding 10kV feeder nodes, n l Indicates the 10kV feeder node corresponding to the upper power supply path of the lth guaranteed power supply user and important user, initialize l = 1, n l =1, l = 1, 2, 3...L, n l =1,2,3,...N l , establish the power grid distance matrix A, where the matrix element a i,j There are several cases of assignment: when i=j, a i,j =0; when i≠j and there is an electrical connection between nodes i and j, element a i,j represents the absolute value of the impedance modulus between nodes i and j; when i≠j and there is no electrical connection A between nodes i and j, then a i,j =∞; 5.

33. Take out the 10kV feeder node n in the grid distance matrix A separately l The row where you are located gets A nl , set 10kV feeder node n l The attribute value d j =0,φ j =null,r j =1, 220kV voltage level transformer node d j =∞,φ j =null,r j =0; 5.

34. Update distance value d j Based on step 5.33, the following formula is used to calculate the absolute value of the impedance modulus from all marked nodes k to the unmarked nodes j directly connected to them: In the formula, R l,j is the resistance value between nodes k and j, X i,j is the reactance value between nodes k and j; 5.

35. Update node tag value r j , select d from all unlabeled nodes j The node s with the smallest value is marked, and its mark value is updated. s =1; 5.36 Update φ j , select the marked parent node k of node s, that is, k is the 10kV feeder node n l The previous node of the shortest path to node s, let φ j = k; 5.

37. Determine whether all 220kV transformer nodes are marked. If they are marked, proceed to the next step. Otherwise, it means that this round of update is not completed, and go to step 5.34 to continue updating. 5.38, if n l ≥N l , then proceed to the next step; otherwise, n l =n l +1 as the initial value, regenerate the power grid distance matrix A, and then go to step 5.33; 5.

39. If l ≥ L, then output the equipment data of all important users and guaranteed power supply users on the power supply path. The equipment data refers to the power supply path with a distance not equal to ∞ that is screened out, and according to φ j All devices on the entire power supply path obtained by the value; otherwise, let l=l+1, n l =1, regenerate the power grid distance matrix A, and go to step 5.33; 5.

40. Determine whether the equipment data obtained on the power supply path of all important users and guaranteed power supply users meet the constraints of the non-risk verification strategy to obtain the verification results, and then make a judgment based on the verification results. If the verification fails, feedback the verification failure information. If the verification passes, go to step 5.4; The non-increase risk verification strategy is: after the load transfer of the power outage for maintenance to be executed, the power supply reliability of the first-level important users and second-level important users with dual power supply will not be further reduced. That is, if the power outage plan has been arranged and one power supply has been cut off, the power supply path of the other power supply cannot have a single power supply, a single bus or a single main transformer due to planned maintenance, and the power outage of equipment that increases the risk of equipment overload and seriously reduces the reliability of power supply should not be arranged. That is, for users with multiple lines or main transformers, multiple devices cannot be cut off for maintenance at the same time, resulting in only one line or one main transformer supplying power; The specific steps of step 5.4 are: judging whether the power supply paths of all important users and guaranteed power supply users meet the verification strategies of guaranteed power supply users of different levels to obtain verification results, and then judging according to the verification results. If the verification fails, feedback is given on the verification failure information; if the verification passes, the verification result of the power outage maintenance order to be dispatched and executed is obtained; The verification strategy for different levels of power supply users is as follows: for first-level power supply users, no planned power outages will be arranged for the 10kV power supply lines, transferable lines and power supply equipment of voltage levels above the power supply users during the power supply guarantee period; for second-level power supply users, no planned power outages will be arranged for the 10kV power supply lines and transferable lines of the power supply users during the power supply guarantee period; for third-level power supply users, no planned power outages will be arranged for the 10kV power supply lines of the power supply users during the power supply guarantee period; under normal operating conditions, the two power supplies for power supply users of different levels cannot come from the same 220 kV substation.

2. A power outage maintenance safety verification system for power transmission and transformation equipment below 220 kV, characterized in that: include: Information acquisition module: reads the real-time power grid topology map in the power system D5000, reads the information of the first-level important users of dual power sources, the second-level important users of dual power sources and the guaranteed power supply users in the SG186 system, wherein the first-level important users and the second-level important users are given users with high requirements for power supply reliability, and the guaranteed power supply users include the first-level guaranteed power supply users, the second-level guaranteed power supply users and the third-level guaranteed power supply users, and obtains all power outage maintenance orders to be dispatched and executed, wherein the information of the power outage maintenance orders to be dispatched and executed includes the power outage time and the power outage range; Load transfer plan generation module: Based on the order of power outage times of each power outage maintenance order to be dispatched and executed, determine the power outage maintenance order to be checked at present, and then generate the load transfer plan of the power outage maintenance order based on the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be dispatched and executed that has been checked and passed; Future maintenance state power grid topology map generation module: Generates the future maintenance state power grid topology map according to the load transfer plan of the current power outage maintenance order to be dispatched and executed; Verification module: Based on the information of first-level important users, second-level important users, power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance orders to be dispatched are verified in turn for no power outage, no overload, no risk increase and power supply guarantee. If any step fails, the failure information is fed back. Otherwise, it is determined whether all the power outage maintenance orders to be dispatched have been verified. If so, the verification results are fed back. If not, the module goes to the load transfer plan generation module to continue to verify the next power outage maintenance order to be dispatched. The specific implementation steps of the load transfer scheme generation module are: Step 3.1, based on the order of the power outage times of each power outage maintenance order to be scheduled and executed, determine the power outage maintenance order to be scheduled and executed that should be checked at present, and then based on all the power outage maintenance orders to be scheduled and executed, perform a union processing on the power outage times of the power outage maintenance orders to be scheduled and executed that overlap in power outage time and power outage range, and obtain the final power outage time of each power outage maintenance order to be scheduled and executed after the union processing, and finally, based on the final power outage time and power outage range, disconnect the corresponding switches and circuit breakers of the power outage equipment involved in the current power outage maintenance order to be scheduled and executed in the real-time power grid topology map or the power grid topology map of the last power outage maintenance order to be scheduled and executed that has been checked and executed, and obtain an updated power grid topology map; Step 3.2: Check the power-off devices based on the updated power grid topology map to obtain all the 10kV busbars that have lost power, and record them as points to be restored; Step 3.3, starting from each switch of the de-energized 10kV busbar, pre-search is performed, and the search paths that do not meet the conditions are feasibility pruned, where the search paths that do not meet the conditions are the paths that require load transfer connected to a dead island, the paths that require load transfer have inoperable equipment, or the branch flow on the load transfer path must exceed the limit after load transfer; Step 3.4: Start from the switches of the de-energized 10kV busbar and conduct a deep search until the energized equipment is found; Step 3.5, starting from the live equipment, search for the 220kV busbar, that is, search for the power supply path to form a complete power supply path. After the power supply path search is completed, all load transfer plans are obtained; The specific implementation steps of the future maintenance state power grid topology map generation module are: According to the load transfer plan, the corresponding switches and circuit breakers on the load transfer path of the updated power grid topology are closed, and the future maintenance state power grid topology consistent with the actual topology is obtained, wherein the future maintenance state power grid topology refers to the modification made on the updated power grid topology when the power outage maintenance order has not been scheduled for execution, assuming that it has been scheduled for execution; The specific implementation steps of the verification module are: Step 5.1: Based on the future maintenance state power grid topology, the power outage maintenance order to be dispatched is checked without power outage. If the check fails, the information of the check failure is fed back. If the check passes, go to step 5.

2. Step 5.2: Based on the future maintenance state power grid topology diagram, the power outage maintenance order to be dispatched is checked for overload. If the check fails, feedback is given on the failure of the check. If the check passes, go to step 5.

3. Step 5.3: Based on the information of primary important users, secondary important users, power supply guarantee users and the future maintenance state power grid topology map, the power outage maintenance order to be dispatched is checked for no risk increase. If the check fails, feedback is given on the check failure. If the check passes, go to step 5.

4. Step 5.4: Based on the information of the first-level important users, the second-level important users, the power supply guarantee users and the future maintenance state power grid topology diagram, the power supply guarantee check is performed on the power outage maintenance order to be dispatched and executed. If the check fails, the information of the check failure is fed back. Otherwise, the power outage maintenance order is checked and passed, and it is determined whether all the power outage maintenance orders to be dispatched and executed have been checked. If so, the check result is fed back. If not, the module goes to the load transfer plan generation module to continue checking the next power outage maintenance order. The specific steps of step 5.1 are: Step 5.11, read the real-time grid topology diagram of the power outage maintenance order to be dispatched or the grid topology diagram of the last verified power outage maintenance order to be dispatched, calculate the power flow using the PQ decomposition method, and obtain the power of each device in the real-time grid topology diagram or the grid topology diagram of the last verified power outage maintenance order to be dispatched; Step 5.12, based on the future maintenance state grid topology of the power outage maintenance order to be dispatched, the PQ decomposition method is used to calculate the power flow to obtain the power of each device in the future maintenance state grid topology; Step 5.13: Based on the two power flow calculation results, compare the two calculation results to determine whether there is any new power outage equipment, and determine whether it meets the constraints of the non-power outage verification strategy according to whether there is any new power outage equipment to obtain the verification result, and then make a judgment based on the verification result. If the verification fails, feedback the verification failure information, and if the verification passes, go to step 5.2; The non-power outage verification strategy is: when the power outage plan for equipment above 10kV bus is implemented, after the power outage and maintenance load of the power outage and maintenance order to be executed by the dispatcher is transferred, it will not cause power outage to users or stations, that is, maintain the status quo; or when the power outage plan for 10kV bus and 10kV distribution line is implemented, after the power outage and maintenance load of the power outage and maintenance order to be executed by the dispatcher is transferred, it will not cause power outage to the first-level important users of dual power sources and the second-level important users of dual power sources; The specific steps of step 5.2 are: Read the future maintenance state grid topology of the power outage maintenance order to be dispatched and executed, calculate the power flow using the PQ decomposition method, and obtain the load rate of each device in the future maintenance state grid topology. According to the power flow calculation result, determine whether it meets the constraint of the non-overload verification strategy to obtain the verification result, and then make a judgment based on the verification result. If the verification fails, feedback the verification failure information. If the verification passes, go to step 5.3; The overload verification strategy is: after the power outage maintenance load is transferred to the power outage maintenance order to be executed by the dispatcher, no equipment will be overloaded, that is, the maximum predicted power of a certain equipment during the power outage will not exceed 90% of its allowable limit; or when the dispatcher performs a switching operation, the power supply mode adjustment after the operation will not cause any equipment to be overloaded, that is, the equipment does not exceed its allowable limit; The step 5.3 adopts a power supply path search strategy to obtain the power supply paths of important users and power supply users based on the future maintenance state power grid topology map, the information of primary important users, secondary important users and power supply guarantee users, and detects whether the power supply paths of important users and power supply guarantee users have added a single power source, a single bus or a single main transformer in the user power supply path due to the implementation of the maintenance plan. The specific implementation process is as follows: 5.31、Set the future maintenance state of the power outage maintenance order to be dispatched and executed. Each node in the power grid topology diagram has a set of attribute values ​​(d j ,φ j , r j ),in, d j represents the absolute value of the impedance modulus on the shortest power supply path from node n to node j of the 10kV feeder; φ j represents the previous node of the shortest power supply path from node n to node j of the 10kV feeder; r j is a 0,1 variable, r j =0 means node j is not marked, r j =1 indicates that node j has been marked. Node refers to any equipment node in the future maintenance state power grid topology diagram, including 220kV voltage level transformer nodes and 10kV feeder nodes. n refers to any 10kV feeder node. 5.

32. Initialization: The power grid has M 220kV voltage level transformer nodes, L guaranteed power supply users and important users, and each guaranteed power supply user and important user has N upstream power supply paths. l corresponding 10kV feeder nodes, n l Indicates the 10kV feeder node corresponding to the upper power supply path of the lth guaranteed power supply user and important user, initialize l = 1, n l =1, l = 1, 2, 3...L, n l =1,2,3,...N l , establish the power grid distance matrix A, where the matrix element a i,j There are several cases of assignment: when i=j, a i,j =0; when i≠j and there is an electrical connection between nodes i and j, element a i,j represents the absolute value of the impedance modulus between nodes i and j; when i≠j and there is no electrical connection A between nodes i and j, then a i,j =∞; 5.

33. Take out the 10kV feeder node n in the grid distance matrix A separately l The row where you are located gets A nl , set 10kV feeder node n l The attribute value d j =0,φ j =null,r j =1, 220kV voltage level transformer node d j =∞,φ j =null,r j =0; 5.

34. Update distance value d j Based on step 5.33, the following formula is used to calculate the absolute value of the impedance modulus from all marked nodes k to the unmarked nodes j directly connected to them: In the formula, R l,j is the resistance value between nodes k and j, X i,j is the reactance value between nodes k and j; 5.

35. Update node tag value r j , select d from all unlabeled nodes j The node s with the smallest value is marked, and its mark value is updated. s =1; 5.36 Update φ j , select the marked parent node k of node s, that is, k is the 10kV feeder node n l The previous node of the shortest path to node s, let φ j = k; 5.

37. Determine whether all 220kV transformer nodes are marked. If they are marked, proceed to the next step. Otherwise, it means that this round of update is not completed, and go to step 5.34 to continue updating. 5.38, if n l ≥N l , then proceed to the next step; otherwise, n l =n l +1 as the initial value, regenerate the power grid distance matrix A, and then go to step 5.33; 5.

39. If l ≥ L, then output the equipment data of all important users and guaranteed power supply users on the power supply path. The equipment data refers to the power supply path with a distance not equal to ∞ that is screened out, and according to φ j All devices on the entire power supply path obtained by the value; otherwise, let l=l+1, n l =1, regenerate the power grid distance matrix A, and go to step 5.33; 5.

40. Determine whether the equipment data obtained on the power supply path of all important users and guaranteed power supply users meet the constraints of the non-risk verification strategy to obtain the verification results, and then make a judgment based on the verification results. If the verification fails, feedback the verification failure information. If the verification passes, go to step 5.4; The non-increase risk verification strategy is: after the load transfer of the power outage for maintenance to be executed, the power supply reliability of the first-level important users and second-level important users with dual power supply will not be further reduced. That is, if the power outage plan has been arranged and one power supply has been cut off, the power supply path of the other power supply cannot have a single power supply, a single bus or a single main transformer due to planned maintenance, and the power outage of equipment that increases the risk of equipment overload and seriously reduces the reliability of power supply should not be arranged. That is, for users with multiple lines or main transformers, multiple devices cannot be cut off for maintenance at the same time, resulting in only one line or one main transformer supplying power; The specific steps of step 5.4 are: judging whether the power supply paths of all important users and guaranteed power supply users meet the verification strategies of guaranteed power supply users of different levels to obtain verification results, and then judging according to the verification results. If the verification fails, feedback is given on the verification failure information; if the verification passes, the verification result of the power outage maintenance order to be dispatched and executed is obtained; The verification strategy for different levels of power supply users is as follows: for first-level power supply users, no planned power outages will be arranged for the 10kV power supply lines, transferable lines and power supply equipment of voltage levels above the power supply users during the power supply guarantee period; for second-level power supply users, no planned power outages will be arranged for the 10kV power supply lines and transferable lines of the power supply users during the power supply guarantee period; for third-level power supply users, no planned power outages will be arranged for the 10kV power supply lines of the power supply users during the power supply guarantee period; under normal operating conditions, the two power supplies for power supply users of different levels cannot come from the same 220 kV substation.

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