CN111929528A - Monitoring and early warning method for fault risk of urban power grid equipment - Google Patents

Abstract

The invention discloses a method for monitoring and early warning of equipment failure risk in a city-region power grid, comprising the following steps: calculating the reduced supply load of the power grid, judging whether it meets the five-level power grid risk early warning; if not, judging whether the six-level power grid risk early warning is satisfied; If it is satisfied, judge whether it meets the seven-level power grid risk warning. The advantages of the present invention are: from the perspective of a single power equipment failure, evaluating the existing potential risks can analyze the result composition and importance of power grid operation risks from the root cause, which is helpful to complete equipment-level control measures for system risks, so as to improve the power system risk management and response capabilities. The intelligent advantage of risk early warning can calculate and adjust the risk level of grid equipment failure by obtaining the operation status of the municipal power grid backup and self-commissioning device in real time, and produce risk early warning prompts. Improve regulation and operation personnel to predict, perceive, manage and control the operation risks of the power grid, strengthen the reliability of power supply, and reduce power outage losses caused by equipment failures.

Description

A method for monitoring and early warning of equipment failure risk in municipal power grid

technical field

The invention relates to a method for monitoring and early warning of equipment failure risk in a city power grid.

Background technique

In order to improve the equipment-level control measures for system risk and improve the risk management and response capability of the power system, a monitoring and early warning system and method for equipment failure risk in the city power grid is designed. This patent provides intelligent early warning for the risks existing in the operation of the power grid from the perspective of a single power equipment failure. Based on the conditional definition of the power grid accident level in the regulation regulations, combined with the actual situation of the voltage level within the city area, the equipment operation risk is given. Identify the process, and obtain real-time information on the switching and withdrawal of related equipment and self-switching equipment. Through intelligent risk warning rules, the grid risk level warning prompt of equipment failure is realized.

Online real-time analysis and generation of power grid equipment failure safety risk early warning provides a reference for effectively controlling power grid equipment failure risks and improves the level of safe operation of the power grid. The successful application of the intelligent technology for early warning of power grid operation risks can improve the accuracy of online analysis of power grid risks, strengthen the risk perception of control centers, equipment operation and maintenance units, and equipment maintenance units, and help reduce power outages in key areas and ensure the safe and stable operation of the power grid. It has a good guiding effect on reliable power supply for users.

With the continuous development of my country's power grid and the advancement of the "three types and two grids" strategy, the scale of the power system continues to expand, the grid structure is increasingly complex, and the safety and stability of power grid equipment has attracted more and more attention. There are more and more potential risks in the operation of power grid equipment, and the task of regulation and operation is becoming more and more onerous. Therefore, the exploration of risk monitoring and early warning technology for power grid equipment failure in prefecture-level cities is of great importance for regulators and operators to predict and manage and control the operation risks of the power grid. significance.

The security and stability of the power grid is mainly reflected in two aspects: the security of power equipment and the stability and security of system operation. The safety of power equipment is the first line of defense for the safety and stability of the power grid. The failure of a single device is often the source of power grid stability problems or cascading failures that lead to large-scale power outages. Therefore, evaluating the potential risks from the perspective of power equipment failure can analyze the result composition and importance of power grid operation risks from the root cause.

At present, the critical degree of risk is mainly determined by grading risk indicators at home and abroad. At present, fuzzy comprehensive evaluation methods are mostly used, and indicators such as loss load, equipment overload, low voltage and overvoltage are used to comprehensively measure the risk level. However, due to the lack of information on the risk indicators themselves, grid operators still cannot grasp the details of the causes and consequences of risks. The potential operation risks caused by the failure of power grid equipment cannot be monitored and controlled in time.

1) The security analysis, early warning and pre-control of the power grid are all deterministic analysis results, that is, refer to the N-1 criterion for dispatching operation.

2) There is a lack of targeted early warning for equipment failures in the operation of the power grid.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the above technical problems and provide a method for monitoring and early warning of the failure risk of power grid equipment in a city area.

In order to solve the above-mentioned technical problems, the present invention is realized through the following technical solutions: a method for monitoring and early warning of equipment failure risk in a municipal power grid, comprising the following steps:

Step 100: Calculate the reduced power supply load of the power grid: Based on the value of calculating the reduced power supply load of a single affected line, the power grid supply reduction load of the area and county area affected by the equipment failure is obtained through a number of accumulations. The specific calculation formula is:

Step 200: Determine whether one of the following three conditions is satisfied:

(1) Cause the power grid to reduce the supply load by more than 100 MW;

(2) The busbars of any voltage level above 220 kV in the substation are stopped unplanned;

(3) One event in a system above 220 kV causes two or more main transformers in the same substation to trip;

Meet one of the five-level power grid risk early warning;

Step 300: In the case that the five-level power grid risk warning is not constituted, determine whether one of the following four conditions is satisfied:

(1) Cause the power grid to reduce the load of more than 40 MW and less than 100 MW;

(2) Unplanned full stop of the 110 kV bus in the substation;

(3) One event causes more than two 110kV main transformers to trip in the same substation;

(4) In the 220 kV system, one event causes more than two busbars in the same substation or more than two circuits in the same transmission section to be shut down at the same time;

Meet one of the six power grid risk early warning;

Step 400: In the case that the six-level power grid risk warning is not constituted, determine whether one of the following four conditions is satisfied:

(1) Abnormal operation of power transmission and transformation equipment above 35 kV or forced to stop operation, resulting in reduced supply and load;

(2) Unplanned full stop of the 35kV bus in the substation;

(3) Unplanned outage of a single bus above 220 kV;

(4) In the 110 kV system, one event causes more than two busbars in the same substation or more than two circuits in the same transmission section to be shut down at the same time;

Meet one of the seven-level power grid risk early warning.

Preferably, the step 200 specifically includes:

Step 210: It is judged that the load reduction caused by the power grid exceeds 100 MW, if yes, carry out a five-level power grid risk warning; if no, go to the next step;

Step 220: Judging that the 220kV bus is unplanned full stop, if yes, carry out a five-level power grid risk warning; if no, go to the next step;

Step 230: Determine whether more than two 220kV main transformers have tripped, and if so, carry out a five-level power grid risk warning; if not, end.

Preferably, the step of judging the unplanned total stop of the 220kV bus in the step 220 is:

Step 221: Obtain the telemetry value of the 220kV busbar voltage in SCADA;

Step 222: judging whether the busbar voltage value is less than 1, and at the same time judging whether the sub-busbar voltage value is less than 1;

Step 223: If both the busbar voltage value and the sub-busbar voltage value are less than 1, it is determined that the 220kV busbar has an unplanned total stop.

Preferably, in the step 230, the step of judging whether more than two 220kV main transformers have tripped is as follows:

Step 231: Obtain the shaking signal value of the 220kV main transformer three-side switch in SCADA;

Step 232: Determine whether the shake signal value of the three-side switch of the main transformer #1 is 0; determine whether the shaking signal value of the three-side switch of the main transformer #2 is 0; determine whether the shaking signal value of the three-side switch of the main transformer #3 is 0;

Step 233: Perform logical operation and addition, determine whether the result is greater than or equal to 2, and if so, determine that more than two 220kV main transformers have tripped.

Preferably, the step 300 specifically includes:

Step 310: It is judged that the power grid reduction load is higher than 40 MW and lower than 100 MW, if yes, carry out a six-level grid risk warning; if not, go to the next step;

Step 320: Determine whether the 220kV same section has more than two outages;

Step 330: Determine whether the 110kV bus is completely stopped unplanned;

Step 340: Determine whether more than two 110kV main transformers have tripped;

Step 350: If the result of steps 320, 330 and 340 is marked as 1, if not marked as 0, perform a logical summation to determine whether the result is greater than or equal to 1, and if so, perform a six-level power grid risk warning.

Preferably, in step 320, the specific method for judging whether the 220kV same section has more than two outages is as follows:

Step 321: The adjacent character matching algorithm judges whether the 220kV line in the same substation has the same section or not, and if so, go to the next step, otherwise cyclic matching;

Step 322: Obtain the telemetry value of the 220kV same-section loop in SCADA;

Step 323: Check whether the active and reactive current telemetry values of line I are less than 1, if yes, mark it as 1, otherwise mark it as 0; if the active and reactive current telemetry values of line II are less than 1, mark it as 1, otherwise mark it as 0 ;

Step 324: Perform a logical judgment to determine whether the values of line I and line II are both 1, and both are 1, which determines that the end face is shut down for more than two times at the same time.

Preferably, the specific method for judging whether the 110kV busbar has an unplanned total shutdown in step 330 is as follows:

Step 331: Obtain the telemetry value of the 110kV busbar voltage in SCADA;

Step 332: Determine whether the voltage value of the positive bus is less than 1; determine whether the voltage value of the sub-bus is less than 1;

Step 333: Make a logical judgment to determine whether the positive bus voltage and the auxiliary bus voltage are both equal to 1, and if so, determine that the 110kV bus is unplanned total shutdown.

Preferably, the specific method for judging whether two or more 110kV main transformers have tripped in step 340 is:

Step 341: Obtain the shaking signal value of the three-side switch of the 110kV main transformer in SCADA;

Step 342: Determine whether the shake signal value of the three-side switch of the main transformer #1 is 0; judge whether the shaking signal value of the three-side switch of the main transformer #2 is 0; judge whether the shaking signal value of the three-side switch of the main transformer #3 is 0;

Step 343: Carry out a logical operation, add the values in Step 342, and determine whether the result is greater than or equal to 2. If so, determine that more than two 110kV main transformers have tripped.

Preferably, the step 400 specifically includes the following steps:

Step 410: Determine whether the load that causes the power grid to be reduced is less than 40 MW, and if yes, perform a seven-level power grid accident early warning, otherwise, go to the next step;

Step 420: Determine whether the 110kV same section has been shut down for more than two times;

Step 430: Determine whether the 35kV bus is completely stopped unplanned;

Step 440: Determine whether the 220kV single bus is out of service unplanned;

Step 450: If the results of steps 420, 430 and 440 are marked as 1, if not marked as 0, perform logical summation to determine whether the result is greater than or equal to 1, and if so, perform a seven-level grid risk warning.

Preferably, in step 420, the specific method for judging whether the 110kV same section is out of service for more than two times is as follows:

Step 421: The adjacent character matching algorithm judges whether the 110kV line in the same substation has the same section or not, and if so, go to the next step, otherwise cyclic matching;

Step 422: Obtain the telemetry value of the 110kV same-section loop in SCADA;

Step 423 : Check whether the active power, reactive power and current telemetry values of the two lines on the same section are all less than 1, if yes, it is determined that the operation is stopped at the same time for more than two times, otherwise, return to step 422 for verification.

Preferably, the specific method for determining whether the 35kV busbar is unplanned total shutdown in step 430 is as follows:

Step 431: Obtain the telemetry value of the 110kV busbar voltage in SCADA;

Step 432: Determine whether the positive bus voltage value is less than 1; determine whether the sub bus voltage is less than 1;

Step 433: Carry out bare metal identification, if both are equal to 1, determine that the 35kV bus is unplanned to stop completely, if otherwise, return to step 431 for verification.

Preferably, the specific method for determining whether the 220kV single busbar is unplanned outage in step 440 is as follows:

Step 441: Obtain the telemetry value of the 220kV busbar voltage in SCADA;

Step 442: Determine whether the positive bus voltage value is less than 1; determine whether the sub bus voltage is less than 1;

Step 443: Perform a logical judgment on whether one of the items is 1, if so, determine that the 220kV single bus is out of service unplanned, if not, return to step 441 to verify once.

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

1) Assessing the potential risks from the perspective of a single power equipment failure can analyze the composition and importance of power grid operation risks from the root cause, which is helpful to complete equipment-level control measures for system risks and improve the risk management and control response of the power system. ability.

2) The intelligent advantage of risk early warning, through real-time acquisition of the operation status of the self-commissioning device of the municipal power grid, calculate and adjust the risk level of grid equipment failure, and produce risk early warning prompts.

3) Improve regulation and operation personnel to predict, perceive, manage and control the operation risks of the power grid, strengthen the reliability of power supply, and reduce power outage losses caused by equipment failures. At the same time, it provides auxiliary guidance for equipment maintenance work.

Description of drawings

FIG. 1 is a flowchart of the five-level power grid risk early warning judgment in the present invention;

Fig. 2 is the sub-flow chart of the unplanned total stop judgment of the 220kV bus in the five-level power grid risk early warning judgment of the present invention;

Fig. 3 is a sub-flow chart of trip judgment of two or more 220kV main transformers in the five-level power grid risk early warning judgment of the present invention;

FIG. 4 is a flowchart of the risk early warning judgment of the six-level power grid in the present invention;

Fig. 5 is a sub-flow diagram of the simultaneous outage judgment of two or more lines of the same transmission section of 220kV in the six-level power grid risk early-warning judgment process of the present invention;

FIG. 6 is a sub-flow diagram of the unplanned total stop judgment of the 110kV bus in the six-level power grid risk early-warning judgment process of the present invention;

Fig. 7 is a sub-flow chart of the trip judgment of two or more 110kV main transformers in the risk early-warning judgment process of the six-level power grid according to the present invention;

Fig. 8 is a flow chart of the seven-level power grid risk early warning judgment in the present invention;

Fig. 9 is a sub-flow chart of the simultaneous outage determination of two or more lines of the same transmission section of 110kV in the seven-level power grid risk early warning determination process of the present invention;

Fig. 10 is a sub-flow chart of judging unplanned full stop of 35kV bus in the seven-level power grid risk early-warning judgment process of the present invention;

Fig. 11 is a sub-flow diagram of the unplanned outage judgment of a 220 kV single bus in the seven-level power grid risk early-warning judgment process of the present invention;

Figure 12 is a schematic diagram of the "source-network-load" interactive simulation model.

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

Technical terms that need to be used in the present invention:

Power system failure: refers to a state in which the equipment cannot work according to the expected indicators, that is to say, the equipment does not achieve the function it should achieve. The failures include the following: generator set failure, transmission line failure, substation failure , bus failure, etc.

Power grid supply load reduction: the actual load reduction of power grids in corresponding administrative regions such as provinces (autonomous regions), provincial capital cities, prefecture-level cities (states), county-level cities, and counties during the accident occurred. This process does not include the load that is restored after the backup is switched on or the reclosing is successful, and the load that is reduced by low-voltage tripping.

Power grid risk early warning: According to the characteristics of the target power equipment, by collecting the topology information of the power grid, monitoring the changing trend of risk equipment, and evaluating the degree of deviation of various risk states from the early warning line, sending early warning signals to the power control center and taking early warning signals. Mechanisms of pre-control countermeasures.

N-1 principle: A criterion for judging the safety of a power system. Also known as the single-failure safety criterion. According to this criterion, after any independent element (generator, transmission line, transformer, etc.) of the N elements of the power system fails and is removed, it should not cause user power outage due to overload tripping of other lines; no damage to The stability of the system is free from accidents such as voltage collapse.

This patent discloses a method for monitoring and early warning of equipment failure risk in a city power grid. Combining with the real-time topology structure of SCADA power grid and the operation status of backup and self-commissioning devices, it can intelligently warn the risks existing in power grid operation from the perspective of a single power equipment failure. Combined with the scope of the city Based on the actual situation of the internal voltage level, the equipment operation risk identification process is given, and the related standby and self-switching equipment is obtained in real time. Through the intelligent risk warning rules, the power grid risk level warning prompt of equipment failure is realized. The details of the technical solution include: load calculation of equipment failure impact, equipment failure risk assessment method and process, intelligent early warning based on the risk level of the power grid topology structure, etc.

1. Calculation of load affected by power grid equipment failure

1) The power grid supply reduction load is based on the calculation of the value of the power supply reduction load of a single affected line, and the power grid supply reduction load in the area and county area affected by the equipment failure is obtained through multiple accumulations. The specific calculation formula (1) is:

In the formula: X——the total number of substations affected within the geographical scope;

2) When the fault or abnormality occurs, the calculation formula of the load that is successfully recovered by the action of the backup and self-throwing device is:

In the formula: W——the number of the backup and self-throwing devices that have successfully operated; P, _{the recovery load of the standby self-throwing (i)} ——the value of the load recovered after the backup and self-throwing operation is successful.

3) The relationship between loss load and supply reduction load The loss load of the power grid can be calculated by using the load curve of the dispatching automation system, and it can be quickly completed after the abnormal fault occurs. The calculation formula is:

P _{grid loss load} = P _{grid supply reduction load} + P _{low voltage tripping load}

= P _{load at the beginning - P load after 30 seconds} - P _{transfer load}

In the formula: P load at the _{start time, P load after 30 seconds} - the corresponding value of the power grid load curve in the OPEN3000 (or D5000) system; P _{transfer load} - the operation of the automatic switching device for each voltage level completes the relevant calculation.

2. Methods and procedures for risk assessment of power grid equipment failures

(1), the construction of evaluation methods

The comprehensive evaluation method should coordinate the three dimensions of power grid security, economy, and high quality. The selection of quantitative evaluation values should be based on the evaluation of the security dimension, supplemented by the economic and high-quality dimensions, namely:

Quantitative evaluation value:

In the formula: V _security ——risk assessment value of security dimension, _Vi ——quantitative risk assessment value of each dimension, Wi——the influence weight value of each dimension on the operation risk of power grid equipment _, and the sum of the weights is 1.

(2) Quantitative level of risk early warning based on power grid events

The risk rating value of power grid equipment operation is divided into three levels for the abnormal operation of power grid transmission and transformation equipment or forced to stop operation due to failure. The identification conditions of power grid events and seven-level power grid events, screening the conditions involving the voltage level of 35kV ~ 220kV within the jurisdiction of the prefecture-level city power grid, respectively give the following three rules.

Five-level power grid event intelligent early warning conditions: (1) The power grid is reduced by more than 100 megawatts of load. (2) Unplanned total shutdown of the busbar of any voltage level above 220 kV in the substation. (3) In a system above 220 kV, one event causes more than two main transformers in the same substation to trip.

Level 6 grid event intelligent early warning conditions: Under the condition that the grid event above level 5 is not constituted, one of the following conditions is met: (1) The power grid reduces the load of more than 40 megawatts and less than 100 megawatts. (2) The 110 kV busbar in the substation is completely unplanned. (3) An event caused more than two 110kV main transformers in the same substation to trip. (4) In the 220 kV system, one event causes more than two busbars in the same substation or more than two circuits in the same transmission section to be shut down at the same time.

Intelligent early warning of level 7 power grid events: Under the condition that the grid event above level 6 is not constituted, one of the following conditions is met: (1) The power transmission and transformation equipment above 35 kV operates abnormally or is forced to stop running, resulting in reduced supply and load. (2) Unplanned full stop of the 35kV bus in the substation. (3) Unplanned outage of a single bus above 220 kV. (4) In the 110 kV system, one event causes more than two busbars in the same substation or more than two circuits in the same transmission section to be shut down at the same time.

Specifically, a method for monitoring and early warning of equipment failure risk in a municipal power grid includes the following steps:

Step 100: Calculate the reduced power supply load of the power grid: Based on the value of calculating the reduced power supply load of a single affected line, the power grid supply reduction load of the area and county area affected by the equipment failure is obtained through a number of accumulations. The specific calculation formula is:

Step 200: Determine whether one of the following three conditions is satisfied:

(1) Cause the power grid to reduce the supply load by more than 100 MW;

(2) The busbars of any voltage level above 220 kV in the substation are stopped unplanned;

(3) One event in a system above 220 kV causes two or more main transformers in the same substation to trip;

Meet one of the five-level power grid risk early warning;

Step 300: In the case that the five-level power grid risk warning is not constituted, determine whether the following four conditions are satisfied:

One of them:

(1) Cause the power grid to reduce the load of more than 40 MW and less than 100 MW;

(2) Unplanned full stop of the 110 kV bus in the substation;

(3) One event causes more than two 110kV main transformers to trip in the same substation;

(4) In the 220 kV system, one event causes more than two busbars in the same substation or more than two circuits in the same transmission section to be shut down at the same time;

Meet one of the six power grid risk early warning;

Step 400: In the case that the six-level power grid risk warning is not constituted, determine whether the following four conditions are satisfied:

One of them:

(1) Abnormal operation of power transmission and transformation equipment above 35 kV or forced to stop operation, resulting in reduced supply and load;

(2) Unplanned full stop of the 35kV bus in the substation;

(3) Unplanned outage of a single bus above 220 kV;

(4) In the 110 kV system, one event causes more than two busbars in the same substation or more than two circuits in the same transmission section to be shut down at the same time;

Meet one of the seven-level power grid risk early warning.

As shown in FIG. 1, the step 200 specifically includes:

Step 210: It is judged that the load reduction caused by the power grid exceeds 100 MW, if yes, carry out a five-level power grid risk warning; if no, go to the next step;

Step 220: Determine the unplanned total shutdown of the 220kV bus, and if so, carry out a five-level power grid risk warning;

If no, go to the next step;

Step 230: Determine whether more than two 220kV main transformers have tripped, and if so, carry out a five-level power grid risk warning; if not, end.

As shown in Figure 2, the steps of judging the unplanned total stop of the 220kV bus in the step 220 are:

Step 221: Obtain the telemetry value of the 220kV busbar voltage in SCADA;

Step 222: judging whether the busbar voltage value is less than 1, and at the same time judging whether the sub-busbar voltage value is less than 1;

Step 223: If both the busbar voltage value and the sub-busbar voltage value are less than 1, it is determined that the 220kV busbar has an unplanned total stop.

As shown in Figure 3, the steps of judging whether more than two 220kV main transformers have tripped in the step 230 are as follows:

Step 231: Obtain the shaking signal value of the 220kV main transformer three-side switch in SCADA;

Step 232: Determine whether the shake signal value of the three-side switch of the main transformer #1 is 0; determine whether the shaking signal value of the three-side switch of the main transformer #2 is 0; determine whether the shaking signal value of the three-side switch of the main transformer #3 is 0;

Step 233: Perform logical operation and addition, determine whether the result is greater than or equal to 2, and if so, determine that more than two 220kV main transformers have tripped.

As shown in Figure 4, the step 300 specifically includes:

Step 310: It is judged that the power grid reduction load is higher than 40 MW and lower than 100 MW, if yes, carry out a six-level grid risk warning; if not, go to the next step;

Step 320: Determine whether the 220kV same section has more than two outages;

Step 330: Determine whether the 110kV bus is completely stopped unplanned;

Step 340: Determine whether more than two 110kV main transformers have tripped;

Step 350: If the result of steps 320, 330 and 340 is marked as 1, if not marked as 0, perform a logical summation to determine whether the result is greater than or equal to 1, and if so, perform a six-level power grid risk warning.

As shown in FIG. 5 , the specific method for judging whether the 220kV same section has more than two outages in step 320 is as follows:

Step 321: The adjacent character matching algorithm judges whether the 220kV line in the same substation has the same section or not, and if so, go to the next step, otherwise cyclic matching;

Step 322: Obtain the telemetry value of the 220kV same-section loop in SCADA;

Step 323: Check whether the active and reactive current telemetry values of line I are less than 1, if yes, mark it as 1, otherwise mark it as 0; if the active and reactive current telemetry values of line II are less than 1, mark it as 1, otherwise mark it as 0 ;

Step 324: Perform a logical judgment to determine whether the values of line I and line II are both 1, and both are 1, which determines that the end face is shut down for more than two times at the same time.

As shown in FIG. 6 , the specific method for determining whether the 110kV busbar is unplanned full stop in step 330 is as follows:

Step 331: Obtain the telemetry value of the 110kV busbar voltage in SCADA;

Step 332: Determine whether the voltage value of the positive bus is less than 1; determine whether the voltage value of the sub-bus is less than 1;

Step 333: Make a logical judgment to determine whether the positive bus voltage and the auxiliary bus voltage are both equal to 1, and if so, determine that the 110kV bus is unplanned total shutdown.

As shown in Figure 7, the specific method for determining whether two or more 110kV main transformers trip in step 340 is as follows:

Step 341: Obtain the shaking signal value of the three-side switch of the 110kV main transformer in SCADA;

Step 342: Determine whether the shake signal value of the three-side switch of the main transformer #1 is 0; judge whether the shaking signal value of the three-side switch of the main transformer #2 is 0; judge whether the shaking signal value of the three-side switch of the main transformer #3 is 0;

Step 343: Carry out a logical operation, add the values in Step 342, and determine whether the result is greater than or equal to 2. If so, determine that more than two 110kV main transformers have tripped.

As shown in Figure 8, the step 400 specifically includes the following steps:

Step 410: Determine whether the load that causes the power grid to be reduced is less than 40 MW, and if yes, perform a seven-level power grid accident early warning, otherwise, go to the next step;

Step 420: Determine whether the 110kV same section has been shut down for more than two times;

Step 430: Determine whether the 35kV bus is completely stopped unplanned;

Step 440: Determine whether the 220kV single bus is out of service unplanned;

Step 450: If the results of steps 420, 430 and 440 are marked as 1, if not marked as 0, perform logical summation to determine whether the result is greater than or equal to 1, and if so, perform a seven-level grid risk warning.

As shown in FIG. 9 , the specific method for judging whether the 110kV same section is out of service for more than two times in step 420 is as follows:

Step 421: The adjacent character matching algorithm judges whether the 110kV line in the same substation has the same section or not, and if so, go to the next step, otherwise cyclic matching;

Step 422: Obtain the telemetry value of the 110kV same-section loop in SCADA;

Step 423 : Check whether the active power, reactive power and current telemetry values of the two lines on the same section are all less than 1, if yes, it is determined that the operation is stopped at the same time for more than two times, otherwise, return to step 422 for verification.

As shown in Figure 10, the specific method for determining whether the 35kV busbar is unplanned total stop in step 430 is as follows:

Step 431: Obtain the telemetry value of the 110kV busbar voltage in SCADA;

Step 432: Determine whether the positive bus voltage value is less than 1; determine whether the sub bus voltage is less than 1;

Step 433: Carry out bare metal identification, if both are equal to 1, determine that the 35kV bus is unplanned to stop completely, if otherwise, return to step 431 for verification.

As shown in FIG. 11 , the specific method for determining whether the 220kV single busbar is unplanned outage in step 440 is as follows:

Step 441: Obtain the telemetry value of the 220kV busbar voltage in SCADA;

Step 442: Determine whether the positive bus voltage value is less than 1; determine whether the sub bus voltage is less than 1;

Step 443: Perform a logical judgment on whether one of the items is 1, if so, determine that the 220kV single bus is out of service unplanned, if not, return to step 441 to verify once.

3. Intelligent risk early warning of power grid equipment

According to the topology structure of the power grid, the intelligent identification of "source-network-load" interactive risk is realized. Through the data interaction between the dispatching automation systems at all levels, the remote signaling and telemetry information of the equipment in SCADA can be obtained, and the automatic splicing of each voltage level can be realized, and the real-time acquisition can be realized. Power grid information to build the "source-grid-load" interactive simulation analysis model, as shown in Figure 12.

The main equipment involved in the jurisdiction of the prefecture-level city power grid, including 220kV ~ 35kV transformers, busbars, lines, etc., is automatically scanned, and the remote signaling and telemetry state changes of associated equipment caused by abnormal or forced shutdown of each equipment are calculated. At the same time, the scanning results are used to analyze the hidden safety hazards of the power grid, predict the trend of the power grid operating status, and obtain the potential unsafe status of the system in the future operating status.

Taking the failure of the main transformer of a substation #2 as an example, the overall steps of intelligently judging the risk warning of power grid equipment are as follows:

Step1. According to the topology of the power grid, obtain the "source-grid-load" interactive simulation analysis model in real time;

Step2. Real-time acquisition of the standby automatic switching device switching status in SCADA. The 220kV Kunyang substation's related standby automatic switching devices Mingshan transformer and Zhenglou transformer 110kV backup automatic switching are in the input state.

Step3. Perform N-1 scan (intelligent identification) on Kunyang transformer #2 transformer, Ding'an transformer, Songqiao transformer #1, leading transformer #1, Yokogawa transformer #2 are in a power-off state.

Step4. Calculate the impact load of the 220kV <Kunyang Transformer #2 Transformer> equipment failure and be forced to shut down the _{power grid to reduce the supply load} . If it exceeds 100MW, it meets the five-level grid risk early warning criteria.

Step5. Other related judgment conditions: The 110kV busbar of Ding'an Substation is unplanned and completely stopped, and the two 110kV main transformers are out of power.

Step 5. The equipment will be warned in the risk warning interface of the municipal power grid equipment, and the relevant station, equipment name, voltage level, the status of the associated self-switching device, the reduced supply load and the warning level will be displayed.

The grid equipment risk warning interface is shown in Table 1.

Table 1

Table 1 shows the equipment with "N-1" problem within the jurisdiction and permit scope of the geological survey in the form of a list, including 220kV main transformers, 110kV lines, 110kV main transformers, 110kV busbars, and 35kV lines.

The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art in the field of the present invention are all covered by the patent scope of the present invention. among.

Claims (12)

1. A method for monitoring and early warning of fault risk of power grid equipment in a city area, characterized in that: comprising the following steps: Step 100: Calculate the reduced power supply load of the power grid: Based on the value of calculating the reduced power supply load of a single affected line, the power grid supply reduction load of the area and county area affected by the equipment failure is obtained through a number of accumulations. The specific calculation formula is:

Step 200: Determine whether one of the following three conditions is satisfied: (1) Cause the power grid to reduce the supply load by more than 100 MW; (2) The busbars of any voltage level above 220 kV in the substation are stopped unplanned; (3) One event in a system above 220 kV causes two or more main transformers in the same substation to trip; Meet one of the five-level power grid risk early warning; Step 300: In the case that the five-level power grid risk warning is not constituted, determine whether one of the following four conditions is satisfied: (1) Cause the power grid to reduce the load of more than 40 MW and less than 100 MW; (2) Unplanned full stop of the 110 kV bus in the substation; (3) One event causes more than two 110kV main transformers to trip in the same substation; (4) In the 220 kV system, one event causes more than two busbars in the same substation or more than two circuits in the same transmission section to be shut down at the same time; Meet one of the six power grid risk early warning; Step 400: In the case that the six-level power grid risk warning is not constituted, determine whether one of the following four conditions is satisfied: (1) Abnormal operation of power transmission and transformation equipment above 35 kV or forced to stop operation, resulting in reduced supply and load; (2) Unplanned full stop of the 35kV bus in the substation; (3) Unplanned outage of a single bus above 220 kV; (4) In the 110 kV system, one event causes more than two busbars in the same substation or more than two circuits in the same transmission section to be shut down at the same time; Meet one of the seven-level power grid risk early warning. 2. The method for monitoring and early warning of equipment failure risk in a municipal power grid according to claim 1, wherein the step 200 specifically comprises: Step 210: It is judged that the load reduction caused by the power grid exceeds 100 MW, if yes, carry out a five-level power grid risk warning; if no, go to the next step; Step 220: Judging that the 220kV bus is unplanned full stop, if yes, carry out a five-level power grid risk warning; if no, go to the next step; Step 230: Determine whether more than two 220kV main transformers have tripped, and if so, carry out a five-level power grid risk warning; if not, end. 3. The method for monitoring and early warning of equipment failure risk in a municipal power grid as claimed in claim 2, wherein the step of judging the unplanned total shutdown of the 220kV bus in the step 220 is: Step 221: Obtain the telemetry value of the 220kV busbar voltage in SCADA; Step 222: judging whether the busbar voltage value is less than 1, and at the same time judging whether the sub-busbar voltage value is less than 1; Step 223: If both the busbar voltage value and the sub-busbar voltage value are less than 1, it is determined that the 220kV busbar has an unplanned total stop. 4. The method for monitoring and early warning of equipment failure risk in a municipal power grid as claimed in claim 2, wherein the step of judging whether more than two 220kV main transformers trip in the step 230 is: Step 231: Obtain the shaking signal value of the 220kV main transformer three-side switch in SCADA; Step 232: Determine whether the shake signal value of the three-side switch of the main transformer #1 is 0; determine whether the shaking signal value of the three-side switch of the main transformer #2 is 0; determine whether the shaking signal value of the three-side switch of the main transformer #3 is 0; Step 233: Perform logical operation and addition, determine whether the result is greater than or equal to 2, and if so, determine that more than two 220kV main transformers have tripped. 5 . The method for monitoring and early warning of equipment failure risk in a municipal power grid according to claim 1 , wherein the step 300 specifically includes: 6 . Step 310: It is judged that the power grid reduction load is higher than 40 MW and lower than 100 MW, if yes, carry out a six-level grid risk warning; if not, go to the next step; Step 320: Determine whether the 220kV same section has more than two outages; Step 330: Determine whether the 110kV bus is completely stopped unplanned; Step 340: Determine whether more than two 110kV main transformers have tripped; Step 350: If the result of steps 320, 330 and 340 is marked as 1, if not marked as 0, perform a logical summation to determine whether the result is greater than or equal to 1, and if so, perform a six-level power grid risk warning. 6. The method for monitoring and early warning of equipment failure risk in a municipal power grid as claimed in claim 5, characterized in that: in step 320, the specific method for judging whether the 220kV same section has more than two outages is: Step 321: The adjacent character matching algorithm judges whether the 220kV line in the same substation has the same section or not, and if so, go to the next step, otherwise cyclic matching; Step 322: Obtain the telemetry value of the 220kV same-section loop in SCADA; Step 323: Check whether the active and reactive current telemetry values of line I are less than 1, if yes, mark it as 1, otherwise mark it as 0; if the active and reactive current telemetry values of line II are less than 1, mark it as 1, otherwise mark it as 0 ; Step 324 : Make a logical judgment to determine whether the values of line I and line II are both 1, and both are 1. This determines that the end face is shut down for more than two times at the same time. 7. The method for monitoring and early warning of equipment failure risk in a municipal power grid as claimed in claim 5, wherein the specific method for judging in step 330 whether the 110kV busbar is unplanned total shutdown is: Step 331: Obtain the telemetry value of the 110kV busbar voltage in SCADA; Step 332: determine whether the voltage value of the positive bus is less than 1; determine whether the voltage value of the sub-bus is less than 1; Step 333: Make a logical judgment to determine whether the positive bus voltage and the auxiliary bus voltage are both equal to 1, and if so, determine that the 110kV bus is unplanned total shutdown. 8. The method for monitoring and early-warning the risk of equipment failure in a municipal power grid as claimed in claim 5, wherein the specific method for determining in step 340 whether two or more 110kV main transformers are tripped is: Step 341: Obtain the shaking signal value of the three-side switch of the 110kV main transformer in SCADA; Step 342: Determine whether the shake signal value of the three-side switch of the main transformer #1 is 0; judge whether the shaking signal value of the three-side switch of the main transformer #2 is 0; judge whether the shaking signal value of the three-side switch of the main transformer #3 is 0; Step 343: Carry out a logical operation, add the values in Step 342, and determine whether the result is greater than or equal to 2. If so, determine that more than two 110kV main transformers have tripped. 9 . The method for monitoring and early warning of equipment failure risk in a municipal power grid according to claim 1 , wherein the step 400 specifically includes the following steps: 10 . Step 410: Determine whether the load that causes the power grid to be reduced is less than 40 MW, and if yes, perform a seven-level power grid accident early warning, otherwise, go to the next step; Step 420: Determine whether the 110kV same section has been shut down for more than two times; Step 430: Determine whether the 35kV bus is completely stopped unplanned; Step 440: Determine whether the 220kV single bus is out of service unplanned; Step 450: If the results of steps 420, 430 and 440 are marked as 1, if not marked as 0, perform a logical summation to determine whether the result is greater than or equal to 1, and if so, perform a seven-level grid risk warning. 10. The method for monitoring and early warning of equipment failure risk in a city-region power grid as claimed in claim 9, characterized in that: the specific method for judging in step 420 whether the 110kV same section is out of service for more than two times is: Step 421: The adjacent character matching algorithm judges whether the 110kV line in the same substation has the same section or not, and if so, go to the next step, otherwise cyclic matching; Step 422: Obtain the telemetry value of the 110kV same-section loop in SCADA; Step 423 : Check whether the active power, reactive power and current telemetry values of the two lines on the same section are all less than 1, if yes, it is determined that the operation is stopped at the same time for more than two times, otherwise, return to step 422 to verify once. 11. The method for monitoring and early warning of equipment failure risk in a municipal power grid as claimed in claim 9, wherein the specific method for judging whether the 35kV busbar is unplanned total shutdown in step 430 is: Step 431: Obtain the telemetry value of the 110kV busbar voltage in SCADA; Step 432: Determine whether the positive bus voltage value is less than 1; determine whether the sub bus voltage is less than 1; Step 433: Carry out bare metal identification, if both are equal to 1, determine that the 35kV bus is unplanned to stop completely, if otherwise, return to step 431 for verification. 12. The method for monitoring and early warning of equipment failure risk in a city-region power grid as claimed in claim 9, characterized in that: the specific method for judging whether the 220kV single busbar is unplanned outage in step 440 is: Step 441: Obtain the telemetry value of the 220kV busbar voltage in SCADA; Step 442: Determine whether the positive bus voltage value is less than 1; determine whether the sub bus voltage is less than 1; Step 443: Perform a logical judgment on whether one of the items is 1, if so, determine that the 220kV single bus is out of service unplanned, if not, return to step 441 to verify once.

Images