CN112994235B - Automatic radiation type power grid risk early warning method based on switch information - Google Patents

Abstract

The application provides a radiation type power grid risk automatic early warning method based on switch information, which comprises the following steps: a risk analysis target switch determining principle is formulated; the collection forms an associated switch set for the target switch; calculating the number of effective electric paths of the target switch and judging the risk type of the target switch; calculating the load loss and the load loss proportion; risk grading and early warning information release. The beneficial effects of the application are as follows: and constructing logic criteria from the position information, the automatic switching state and the flowing power direction information of the switch by taking important risk event early warning of the regional power grid as a target, analyzing possible power grid risk events on line, calculating event grades, and carrying out early warning to provide the most visual power grid risk judgment for dispatching and operating operators.

Description

An automatic early warning method for radiation power grid risks based on switch information

Technical field

The present disclosure relates to the technical field of power grid risk early warning, and specifically relates to a radiation-type power grid risk automatic early warning method based on switch information.

Background technique

With the development of power grids, control, operation and management tasks are becoming increasingly complex, and power grid risk management is becoming more and more difficult. Being able to analyze power grid risks online and achieve automatic early warning is of great significance to dispatching operations. Existing risk early warning methods are mostly from the perspective of equipment and power grids. Factors considered are mainly the aging and failure of equipment, the stability limit and operating limit of the power grid, environmental factors of severe weather and human misoperation, etc. Most of the analysis methods are based on Power flow calculation or probabilistic power flow calculation, by establishing a probability model, measures the risk based on the probability and the degree of possible accident consequences, and carries out risk warning.

The above methods can more comprehensively evaluate the overall risk level of the power grid, but they often require a large amount of calculations, involve complex factors, and are affected by errors in various aspects. In dispatching operation work, dispatchers are more concerned about the impact that a certain switch position will have on the power grid during planned maintenance or temporary mode adjustment, and whether it constitutes a power grid event or generates power grid risks. Therefore, the existing methods are not targeted at Risk warning for power grid events is not very practical.

Contents of the invention

The purpose of this application is to provide an automatic early warning method for radial power grid risks based on switch information in response to the above problems.

In the first aspect, this application provides an automatic early warning method for radiated power grid risks based on switch information, which includes the following steps:

S1. Develop risk analysis target switch determination principles;

S2. Set to form an associated switch set about the target switch;

S3. Calculate the number of effective electrical paths of the target switch;

S4. Determine the risk type of the target switch;

S5. Calculate load loss and load loss ratio;

S6. Risk grading and issuing early warning information.

According to the technical solution provided by the embodiment of this application, step S2 specifically includes:

Select the startup switch and determine the risk analysis target switch based on the startup switch;

(1) If the starting switch is a line switch, the target switch determination principle is:

1) If the position value of the switch on the opposite side of the start switch is 0, the switch on the opposite side is turned off and the self-throwing status is determined:

i. If the self-throwing status value is 0, the line is defined as a power outage and there is no target switch;

ii. If the self-throwing state value is 1, the line is defined as the backup power state, and the target switch is determined to be the opposite switch;

2) If the position value of the switch on the opposite side of the start switch is 1, the switch on the opposite side is closed and the power flow direction begins to be determined:

i. If the power flow direction of the start switch is positive, determine the target switch to be the opposite switch;

ii. If the power flow direction of the start switch is negative, determine the target switch as the start switch;

(2) If the starting switch is a bus tie switch, set all line switches as starting switches and start analysis in sequence;

(3) If the start switch is controlled by the main switch, the target switch determination principle is:

1) If the starting switch is the high-voltage receiving main switch, it is equivalent to selecting the medium-voltage receiving main switch and the low-voltage receiving main switch of the main transformer as the starting switches at the same time;

2) If the starting switch is a non-high-voltage main switch, it is equivalent to a line switch of the same voltage level. Replace other main switch types of the same voltage level in the substation with line switches and define the operation value of the opposite side switch as 1.

According to the technical solution provided by the embodiment of the present application, the set forms an associated switch set about the target switch, which specifically includes: screening all switches with the same name as the target switch station in the switch information matrix, and screening the incoming switch lines therein. For the switch on the opposite side, all the above switches form an associated switch set, and all switch incoming lines are renumbered.

According to the technical solution provided by the embodiment of this application, step S3 specifically includes:

(1)

In the formula, i represents the i -th incoming line switch, x represents a total of x incoming line switches in the associated switch set;

For the incoming line switch numbered i , its switch position value is , the position value is 1 when the switch is closed, and the position value is 0 when the switch is open;

For the incoming line switch numbered i , the switch self-turning state value is , the status value is 1 when self-investment is put in, and the status value is 0 when self-investment is exited;

For the incoming line switch numbered i , the switch operation value is , and/> ;

is the calculated value of the line where the i- th incoming switch is located, and the number of the switch on the opposite side is j , then/> ;

For the bus switch numbered i , its switch position value is , the position value is 1 when the switch is closed, and the position value is 0 when the switch is open;

For the bus switch numbered i , the switch self-turning state value is , the status value is 1 when self-investment is put in, and the status value is 0 when self-investment is exited;

For the bus switch numbered i , its switching operation value is , and/> ;

is the bus link coefficient. For the incoming switch running on the same bus as the target switch, the bus link coefficient is 1. For the switch not running on the same bus as the target switch, the bus link coefficient is equal to the bus link between the two buses. The product of joint/segment switch operation values,/> .

According to the technical solution provided by the embodiment of this application, step S4 specifically includes:

S41. When 0<K<K ₀ , there is currently a risk of N-1 power outage, where the value of K ₀ is set to 1.2~1.5;

S42. When K ₀ <K <K ₁ , after pulling the start switch, N-1 power outage risk will occur in the substation where the risk target analysis switch is located, where the value of K ₁ is set to 2.2~2.5;

S43. Risk type judgment: When there is a risk in step S41 or S42, if the bus tie coefficient between the minimum and maximum busbars corresponding to the voltage level =1, then it is determined that there is a risk of N-1 bus total outage. At the same time, if the bus voltage level is equal to the highest voltage level of the station, then it is further determined that there is a risk of total station power outage; if/> =0, then it is determined that there is a risk of N-1 bus power outage;

S44. Count the number n of N-1 power outage risks for buses of the same voltage level in the same substation. When n=n ₀ , the risk type is corrected to the N-1 bus total outage risk, and return to step S43, where n ₀ is the voltage level bus. Quantity; set the bus connection operation value of the corresponding number of low-voltage buses with N-1 power outage risk buses to 0;

S45. Find risks in receiving substations of the same voltage level. If the analysis and determination result of the target switch indicates that the substation has N-1 power outage risk, then select all switches with positive power direction on the corresponding bus as the start switch and find the associated switch set. Calculate the effective power supply path, and the criterion for the existence of N-1 risks is: K-1<K ₀ .

According to the technical solution provided by the embodiment of this application, step S5 specifically includes:

S51. Taking the risk set obtained in step S4 as the target, the high-voltage bus N-1 power outage risk is equivalent to the high-voltage receiving total N-1 power outage on the bus, and then equivalent to the medium- and low-voltage side total receiving switches N corresponding to the main transformer. -1 power outage. At this time, the power outage risk criterion of the low-voltage bus is: K<K ₀ ;

S52. Target the medium and low-voltage buses with N-1 power outage risk in the above S51 step, set all line switches on the bus as start switches, repeat step S4, and find lower-level risk points;

S53. Repeat steps S4-S51 until the found bus voltage level is 35kV or 10kV;

S54, load loss statistics, take all 35kV and 10kV buses that are at risk of power outage as the target, accumulate the active power values of all outlets at the sampling moment before the target switch displacement or simulated displacement, and obtain the load loss size S _Σ ;

S55. Calculate the load loss proportion. According to the load area attributes, calculate the load loss sizes S ₁ , S ₂ , S ₃ , ... in each region respectively, and compare them with the total load in each region at the same time to obtain the load loss proportion S ₁ % , S ₂ %, S ₃ %,….

According to the technical solutions provided by the embodiments of this application, the risk grading and early warning information release specifically include:

Match the N-1 risk event type with load loss and load loss proportion with the risk event database to perform risk rating and generate early warning information;

Publish power grid risk warning through the D5000 system pop-up window.

Beneficial effects of the present invention: This application provides a radial power grid risk automatic early warning method based on switch information, starting from the actual needs of regional power grid dispatching operations, aiming at early warning of major risk events in the regional power grid, and based on the location information of switches, Logical criteria are constructed from the automatic switching status and flowing power direction information to analyze possible grid risk events online, calculate event levels, and provide early warning to provide the most intuitive grid risk judgment for dispatch and operation personnel.

Description of drawings

Figure 1 is a flow chart of the first embodiment of the present application;

Figure 2 is a schematic diagram of a power grid connection of a specific example of the first embodiment of the present application.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present application will be described in detail below in conjunction with the accompanying drawings. The description in this part is only exemplary and explanatory, and shall not have any limiting effect on the protection scope of the present application. .

Figure 1 is a schematic diagram of the first embodiment of the present application, which includes the following steps:

S1. Develop risk analysis target switch determination principles.

This step specifically includes:

Select the start switch and determine the risk analysis target switch (hereinafter referred to as the target switch) based on the start switch.

In this embodiment, the start switch is generated by actual switch displacement information or simulated operation.

(1) If the starting switch is a line switch, the target switch determination principle is:

1) If the position value of the switch on the opposite side of the start switch is 0, the switch on the opposite side is turned off and the self-throwing status is determined:

i. If the self-throwing state value is 0, the line is defined as a power outage state, there is no target switch, and it ends;

ii. If the self-throwing state value is 1, the line is defined as the backup power state, and the target switch is determined to be the opposite switch;

2) If the position value of the switch on the opposite side of the start switch is 1, the switch on the opposite side is closed and the power flow direction begins to be determined:

i. If the power flow direction of the start switch (previous sampling value) is positive (outflow), then the target switch is determined to be the opposite switch;

ii. If the power flow direction of the start switch (previous sample value) is negative (inflow), then the target switch is determined to be the start switch.

(2) If the starting switch is a bus tie switch, set all line switches as starting switches and start analysis in sequence, that is, follow steps 1) and 2) in step (1) above.

(3) If the start switch is controlled by the main switch, the target switch determination principle is:

1) If the starting switch is the high-voltage receiving main switch, it is equivalent to selecting the medium-voltage receiving main switch and the low-voltage receiving main switch of the main transformer as the starting switches at the same time;

2) If the starting switch is a non-high-voltage main switch, it is equivalent to a line switch of the same voltage level. Replace other main switch types of the same voltage level in the substation with line switches and define the operation value of the opposite side switch as 1.

S2. Set to form an associated switch set about the target switch.

This step specifically includes: screening all switches with the same name as the target switch station in the switch information matrix, screening the switches on the opposite side of the incoming switch line, forming an associated switch set with all the above switches, and re-processing all switch incoming lines. serial number.

The switch information matrix includes all switches: station name, type, switch position information, automatic switching status, active power value, load area attributes, switch voltage level, switch operating bus, opposite switch number information, collected from SCADA The above raw data obtained form the matrix A, and the above information is digitally processed to form the switch information matrix B, where:

Station name: substation name, sorted by 1-m respectively, and replace the substation name with the serial number;

Type: Set the incoming line switch, medium and low voltage outlet switch, transformer high voltage receiving main switch, transformer medium and low voltage receiving main switch options. If the corresponding type is met, the value will be 1 in the matrix, otherwise it will be 0;

Switch position information: switch closed is 1, switch open is 0;

Self-investment status: Self-investment investment is 1, self-investment exit is 0;

Active power value: the power value P flowing through the switch;

Power flow direction value: In order to avoid the influence of the power sampling value error of the empty charging line, the power sensitivity value P ₀ is set. When P > P ₀ , the power direction is considered to flow out, and the value is 0, otherwise the value is 1;

Incoming line switch: a line switch with a power flow value of 1;

Load area attributes: Mark the 35kV and 10kV distribution network transmission lines according to the county, district, and city where the power supply area is located, with numbers 1, 2, 3,... representing the areas where the loads they supply are respectively;

Switching voltage level: Set the 220kV, 110kV, 35kV, 10kV options. If the corresponding type is met, the value will be 1 in the matrix, otherwise it will be 0;

Switch running bus: Set the 1, 2, 3,... number options representing the bus. When running on the corresponding bus, take 1, otherwise it will be 0; the bus numbering rule is to arrange in ascending order according to the bus name, the smallest number corresponds to the number 1, A, B The busbar A in the busbar corresponds to the smaller number;

Opposite side switch number information: The number of the switch on the opposite side of the switch line with the type "incoming line switch", and the opposite side number value of other switches is 0.

S3. Calculate the number of effective electrical paths of the target switch.

This step specifically includes:

(1)

In the formula, i represents the i -th incoming line switch, x represents a total of x incoming line switches in the associated switch set (including the target switch);

For the incoming line switch numbered i , its switch position value is , the position value is 1 when the switch is closed, and the position value is 0 when the switch is open;

For the incoming line switch numbered i , the switch self-turning state value is , the status value is 1 when self-investment is put in, and the status value is 0 when self-investment is exited;

For the incoming line switch numbered i , the switch operation value is , and/> ;

is the calculated value of the line where the i- th incoming switch is located, and the number of the switch on the opposite side is j , then/> ;

For the bus switch numbered i , its switch position value is , the position value is 1 when the switch is closed, and the position value is 0 when the switch is open;

For the bus switch numbered i , the switch self-turning state value is , the status value is 1 when self-investment is put in, and the status value is 0 when self-investment is exited;

For the bus switch numbered i , its switching operation value is , and/> ;

is the bus link coefficient. For the incoming switch running on the same bus as the target switch, the bus link coefficient is 1. For the switch not running on the same bus as the target switch, the bus link coefficient is equal to the bus link between the two buses. The product of joint/segment switch operation values,/> .

S4. Determine the risk type of the target switch.

This step specifically includes:

S41. When 0<K<K ₀ , there is currently a risk of N-1 power outage, and the value of K ₀ is set to 1.2~1.5.

S42. When K ₀ <K <K ₁ , after pulling the start switch, N-1 power outage risk will occur in the substation where the risk target analysis switch is located, where the value of K ₁ is set to 2.2~2.5.

S43. Risk type judgment: When there is a risk in step S41 or S42, if the bus tie coefficient between the minimum and maximum busbars corresponding to the voltage level =1, then it is determined that there is a risk of N-1 bus total outage. At the same time, if the bus voltage level is equal to the highest voltage level of the station, then it is further determined that there is a risk of total station power outage (equivalent to the risk of N-1 power outage for all high-voltage buses) ;if/> =0, it is determined that there is a risk of N-1 bus power outage.

S44. Count the number n of N-1 power outage risks of buses with the same voltage level in the same substation in this startup risk analysis. When n=n ₀ , the risk type is corrected to the N-1 bus total outage risk, and return to step S43, where n ₀ is the number of voltage level buses; set the bus connection calculation value of the corresponding number of low-voltage buses with N-1 power outage risk buses to 0; in this step, the start-up risk analysis starts with manual selection of the start switch, and manual elimination or The automatic risk elimination warning cycle is released to end.

S45. Find risks in receiving substations of the same voltage level. If the analysis and determination result of the target switch indicates that the substation has N-1 power outage risk, then select all switches with positive power direction on the corresponding bus as the start switch and find the associated switch set. Calculate the effective power supply path, and the criterion for the existence of N-1 risks is: K-1<K ₀ .

S5. Calculate load loss and load loss ratio.

This step specifically includes:

S51. Taking the risk set obtained in step S4 as the target, the high-voltage bus N-1 power outage risk is equivalent to the high-voltage receiving total N-1 power outage on the bus, and then equivalent to the medium- and low-voltage side total receiving switches N corresponding to the main transformer. -1 power outage. At this time, the power outage risk criterion of the low-voltage bus is: K<K _0.

S52. Target the medium and low-voltage buses with N-1 power outage risk in step S51 above, set all line switches on the bus as start switches, and repeat step S4 to find lower-level risk points.

S53. Repeat steps S4-S51 until the found bus voltage level is 35kV or 10kV.

S54, load loss statistics, take all 35kV and 10kV buses that are at risk of power outage as the target, accumulate the active power values of all outlets at the sampling moment before the target switch displacement or simulated displacement, and obtain the load loss size S _Σ .

S55. Calculate the load loss proportion. According to the load area attributes, calculate the load loss sizes S ₁ , S ₂ , S ₃ , ... in each region respectively, and compare them with the total load in each region at the same time to obtain the load loss proportion S ₁ % , S ₂ %, S ₃ %,….

S6. Risk grading and issuing early warning information.

In this step, the risk is graded and early warning information is issued, specifically including:

S61. Match the N-1 risk event type with the load loss and load loss ratio with the risk event library to perform risk rating and generate early warning information;

S62. Issue power grid risk warning through the D5000 system pop-up window.

In this embodiment, the manual elimination function is set in the pop-up window of the D5000 system. Manual elimination can end the risk warning cycle issuance; before manual elimination, risk analysis and early warning will be carried out again every 5 minutes with the established target switch as the target until the power grid mode changes. This will make the risk matching disappear and end the warning cycle.

The risk event database described in this embodiment mainly selects the types of events involving busbar, main transformer power outage and load loss within the jurisdiction of regional power grids in the "State Grid Corporation Dispatch System Major Event Reporting Regulations", including:

Level 4 power grid incidents: 1) Those that cause the regional power grid to reduce supply load by more than 4% and less than 10%; 2) Those that cause the municipal power grid to reduce supply by more than 5% and less than 20%; 3) Those that cause other districted municipal power grids to reduce supply by 20% Those who are above; 4) Those who cause the county-level city power grid with a power grid load of more than 150 megawatts to reduce the supply load by more than 40%; 5) Those who cause the county-level city power grid with a power grid load of less than 150 megawatts to reduce the supply load by more than 40%;

Level 5 power grid events: 1) Those that cause the power grid to reduce supply load by more than 100 megawatts; 2) Unplanned total shutdown of any voltage level busbar above 220 kV in a substation; 3) In a system above 220 kV, one incident causes the same substation to Two or more main transformers trip inside;

Level 6 power grid incidents: 1) Causes power grid supply load reduction of more than 40 MW and less than 100 MW; 2) Unplanned total shutdown of the 110 kV bus in the substation; 3) An incident causes more than two 110 kV mains in the same substation becomes tripped.

In this embodiment, a certain switch is selected as the start switch, and the power grid risk events caused by the switch displacement can be automatically obtained through simulated operations, helping the on-duty dispatcher to conduct risk analysis on the operation tasks, and effectively avoiding power grid risk events caused by improper arrangement of the power grid. As the level increases, the on-duty dispatcher can get real-time early warning of power grid risk events, effectively strengthen the management and control of power grid risk events and reasonably avoid power grid risks. The switch information is used for analysis, which avoids traditional power flow or probabilistic power flow calculations, reduces the amount of calculation, and achieves rapid early warning; considering that accidents in superior substations also bring risks to the receiving substation, a step-by-step analysis is performed to calculate 35kV and 10kV Distribution network transmission lines are the ultimate goal to determine the possible load losses caused by grid risks and fully meet the needs of grid risk event classification in actual dispatching operations.

As shown in Figure 2, it is a schematic diagram of the power grid connection of a specific example of the first embodiment of the present application. The 35kV and 10kV load conditions of each station are:

220kV I station: none;

220kV II station: None;

110kV station a: 10kV bus 4: 14MW (area A load);

10kV No. 5 busbar: 6MW (area A load);

10kV No. 5 B bus: 10MW (area A load);

10kV No. 6 bus: 8MW (area A load);

110kV station b: 10kV bus 4: 14MW (area A load);

10kV No. 5 busbar: 5MW (area A load);

10kV No. 5 B bus: 7MW (area A load);

110kV station c: 10kV bus 4: 8MW (area B load);

10kV No. 5 bus: 6MW (area B load);

Region A: County-level city, total load 131MW;

Area B: County, total load 76MW.

The following is an analysis based on this section:

(1) Simulation: Open the 111 switch of 110kV station c

1. Select start switch 111.

2. Determine that the power flow direction of the 111 switch is negative (into the bus), and determine that the risk analysis target switch is the switch on this side of the line, that is, the 111 switch itself.

3. The associated switch set formed by search is: 121 switch of 220kV station II, 111 switch, 145 switch, 201 switch, 202 switch and 10kV outlet switches of 110kV station c (reflected in the load loss analysis link).

4. Calculation of the number of effective power supply paths:

(1) Search for the 110kV incoming line switch in the associated switch set, and the result is: 111 switch; search for the 110kV bus tie (section) switch in the associated switch set, and the result is 145 switch;

(2) The 111 switch is in the closed position, and the calculated value c ₁ =1. The 121 switch of the 220kV II station is in the closed position, and the calculated value c ₁₂ =1; therefore, the line calculated value α ₁ =c ₁ · c ₁₂ =1; effective power supply path quantity: .

5. Risk type determination:

because , and/> , so the current 110kV c station has the risk of N-1 station-wide power outage, and the tripping of the 111 switch will directly cause the entire station to lose power;

There is currently a risk of N-1 power outage, that is, tripping of start switch 111 will directly cause equipment power outage and load loss.

Fanxun load loss: (1) The 35kV and 10kV power outage buses under Fanxun N-1 fault include: 110kV station c, 10kV No. 4 bus, and 10kV No. 5 bus;

(2) Load loss calculation results:

The total load loss is 14MW<100MW, which does not constitute a Level 5 power grid risk;

Area B lost load 14MW.

Risk grading, issuing early warning pop-up window: (1) The risk levels obtained from this risk analysis are: 110kV station c, 110kV bus is completely stopped, six-level power grid risk;

(2) Issue a risk warning pop-up window: After the 111 switch of 110kV station c is disconnected, an unplanned power outage will cause a level 6 power grid incident.

(2) Simulation: Open the 102 switch of 220kV I station

1. Select start switch 102.

2. It is judged that 102 is not the high-voltage main switch of the station, and is equivalent to the 110kV bus incoming switch of the station.

3. Search to form the associated switch set: 2211, 2212, 2201, 2202, 2245, 2213, 2214, 101, 102, 111, 119, 120, 201, 202 switches at 220kV I station, and replace the 101 switch type with the incoming line switch .

4. Calculation of the number of effective power supply paths:

(1) Search the 110kV incoming line switch in the related switch set, and the result is: 101, 102 switches; search the 110kV bus tie (section) switch in the related switch set, and the result is 145A switch;

(2) The 101 switch is in the closed position, the operation value c ₁ =1, the opposite end switch operation value is set to 1, so the line operation value α ₁ =1; the 102 switch is in the closed position, the operation value c ₂ =1, the opposite end switch operation The value is set to 1, so the line operation value α ₂ =1, the bus link 145 A switch is closed, the bus link coefficient β ₂ =1; the number of effective power supply paths: .

5. Risk type determination:

because , and/> , so the current 110kV bus does not have the risk of N-1 power outage. After the 102 switch is disconnected, there will be the risk of N-1 110kV bus total power outage.

Fanxun load loss: (1) The 35kV and 10kV power outage buses under Fanxun N-1 fault include: 110kV station b, 10kV No. 5A, 10kV No. 5B, and 10kV No. 6 bus;

(2) Load loss calculation results:

The total load loss is 26MW<100MW, which does not constitute a level five power grid risk;

The lost load in Area A is 26MW<100MW, accounting for 19.8<40% of county-level cities, and does not constitute a fourth-level power grid risk.

Risk grading and early warning pop-up windows: (1) The risk levels obtained from this risk analysis are: 220kV station I station has all 110kV buses stopped, a six-level power grid risk; 220kV station II station 110kV buses have all stopped, a six-level power grid risk ; The 110kV bus of 110kV station b is completely stopped, resulting in a six-level power grid risk; (2) A risk warning pop-up window is issued: After the 102 switch of 220kV station I is disconnected, an N-1 level six power grid risk occurs.

(3) Simulation: Turn on the 2216 switch of XX power plant station

1. Select start switch 2216.

2. Determine that the power flow direction of the 2216 switch is positive (out of the bus), and determine that the risk analysis target switch is the switch on the opposite side of the line, that is, the 2211 switch.

3. Search to form the associated switch set: 2211, 2212, 2201, 2202, 2245, 2213, 2214, 101, 102, 111, 119, 120, 201, 202 switches at 220kV I station.

4. Calculation of the number of effective power supply paths:

(1) Search for the 110kV incoming line switch in the associated switch set, and the result is: 2211, 2212 switches; search for the 220kV bus coupler (section) switch in the associated switch set, and the result is 2245 switch.

(2) The 2212 switch is in the closed position, and the operation value c ₁ =1. The opposite switch 2215 is in the closed position, and the operation value c ₁₂ =1, so the line operation value α ₁ =1; the 2211 switch is in the closed position, and the operation value c ₂₁ =1, the 2216 switch is in the closed position, the operation value c ₂₂ =1, so the line operation value α ₂ =0, the bus link 2245 switch is in the closed position, the bus link coefficient β ₂ =1; the number of effective power supply paths: .

5. Risk type determination:

(1) Due to , and/> , so there is no risk of N-1 power outage for the 220kV busbar of 220kV Station I. After the 2216 switch of XX Power Plant is disconnected, there will be a risk of N-1 220kV busbar blackout;

(2) Search results for risk points at the same level: After the 2216 switch of XX Power Plant is disconnected, the 220kV II station also generates the risk of total power outage of the N-1220kV bus.

6. Search for load loss:

(1) Search results for lower-level risk points:

After switch 2216 of XX power plant is disconnected, after switch 2216 of XX power plant is disconnected, 220kV station I 110kV busbar, 220kV station II 110kV busbar, 110kV station a 110kV No. 4, 5, and 6 bus, 110kV station b 110kV No. 4, 5 There is an N-1 total shutdown risk for bus No. 4 and No. 6, and 110kV bus No. 4 and No. 5 at station c;

(2) The 35kV and 10kV power outage buses under N-1 fault are:

220kV Station I 10kV bus No. 4, No. 5, 220kV Station II 10kV bus No. 5, No. 6 bus, 110kV Station a 10kV No. 4, No. 5A, No. 5B, No. 6 bus, 110kV Station B 10kV No. 5A, 5 No. B, No. 6 bus, 110kV station c, 10kV No. 4 and No. 5 bus.

(3) Calculation results of load loss:

The total load lost is 88MW<100MW, which does not constitute a level five power grid risk;

Area A lost 64MW of load, accounting for 48.9% > 40% of the county-level city’s total load, posing a fourth-level power grid risk;

Area B lost load 14MW.

7. Risk rating and issuing early warning pop-ups:

(1) The risk levels obtained from this risk analysis are as follows: 220kV station I station’s 220kV busbar is completely stopped, a level five power grid risk; 220kV station II station’s 220kV busbar is completely stopped, a level five power grid risk; 220kV station I station’s 110kV busbar is completely stopped, a level six power grid risk Level 1 grid risk; 220kV station II, all 110kV buses are stopped, level 6 grid risk; 110kV station a, all 110kV buses are stopped, level 6 grid risk; 110kV station b, 110kV busbar is all stopped, level 6 grid risk; 110kV station c, 110kV If all buses are stopped, the risk will be level 6. The load loss in area A exceeds 40%, which is level 4 risk.

(2) Issue a risk warning pop-up window: After the 2216 switch of XX Power Plant is disconnected, N-1 level four power grid risk will occur.

This article uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above examples is only used to help understand the method and the core idea of the present application. The above are only preferred embodiments of the present application. It should be pointed out that due to the limitations of written expressions, there are objectively unlimited specific structures. For those of ordinary skill in the art, without departing from the principles of the present application, Under the circumstances, several improvements, modifications or changes can also be made, or the above technical features can be combined in an appropriate manner; these improvements, modifications or combinations, or the applied concepts and technical solutions can be directly applied to other situations without improvement. , shall be regarded as the protection scope of this application.

Claims (4)

1. The automatic radiation type power grid risk early warning method based on the switch information is characterized by comprising the following steps of:

s1, formulating a risk analysis target switch determination principle;

s2, forming an associated switch set related to the target switch in a set manner;

s3, calculating the number of effective electrical paths of the target switch;

s4, judging the risk type of the target switch;

s5, calculating the load loss and the load loss proportion;

s6, risk grading and issuing early warning information;

the step S1 specifically comprises the following steps:

selecting a starting switch, and determining a risk analysis target switch according to the starting switch;

(1) If the start switch is a line switch, the target switch determination principle is:

1) If the position value of the opposite side switch of the starting switch is 0, the opposite side switch is disconnected, and the automatic switching state is judged:

i. if the self-switching state value is 0, the line is defined as a power failure state without a target switch;

if the self-switching state value is 1, defining a line as a standby power supply state, and determining that the target switch is a contralateral switch;

2) If the position value of the opposite side switch of the starting switch is 1, the opposite side switch closes, and the power flow direction is judged:

i. if the power flow direction of the starting switch is positive, determining that the target switch is a contralateral switch;

if the power flow direction of the start switch is negative, determining the target switch as the start switch;

(2) If the starting switch is a bus-bar switch, setting all the line switches as starting switches and sequentially starting analysis;

(3) If the starting switch is the main switch, the target switch determining principle is as follows:

1) If the starting switch is a high-voltage main switch, the equivalent is that the medium-voltage main switch and the low-voltage main switch of the main transformer are simultaneously selected as the starting switch;

2) If the starting switch is a non-high voltage main switch, the starting switch is equivalent to a same-voltage-class line switch, other same-voltage-class main switch types of the transformer substation are replaced by line switches, and the operation value of the opposite-side switch is defined as 1;

wherein, the step S2 specifically comprises: screening all switches with the same station name as the target switch in a switch information matrix, screening opposite side switches of an incoming line switch circuit in the switch information matrix, forming an associated switch set by all the switches, and renumbering incoming lines of all the switches;

wherein, the step S3 specifically comprises:

（1）

in the method, in the process of the application,irepresent the firstiA plurality of wire inlet switches,xrepresenting associated switch setsCo-productionxA plurality of incoming line switches;

number of pairs isiThe switch position value of the incoming line switch isThe position value of the switch is 1 when the switch is closed, and the position value of the switch is 0 when the switch is opened;

number of pairs isiThe incoming line switch of (2) has a switch self-switching state value ofThe state value at the time of automatic switching is 1, and the state value at the time of automatic switching is 0;

number of pairs isiThe switch operation value of the incoming line switch isAnd->；

Is the firstiThe operation value of the line where the incoming line switches are positioned makes the opposite side switch number of the incoming line switch bejThen->；

Number of pairs isiThe bus switch has a switch position value ofThe position value of the switch is 1 when the switch is closed, and the position value of the switch is 0 when the switch is opened;

number of pairs isiThe bus switch of which has a switch self-switching state value ofThe state value at the time of automatic switching is 1, and the state value at the time of automatic switching is 0;

number of pairs isiBus switch of (a) the switch operation value of whichIs thatAnd->；

For the bus-in coefficient, for the incoming line switch running on the same bus as the target switch, the bus-in coefficient is 1, for the switch not running on the same bus as the target switch, the bus-in coefficient is equal to the product of the bus-in/sectionalizing switch operation values between the two buses>。

2. The automatic radiation type power grid risk early warning method based on switch information according to claim 1, wherein the step S4 specifically comprises the following steps:

s41, when 0<K<K ₀ When there is a current risk of N-1 power failure, wherein K ₀ The numerical value of (2) is set to be 1.2-1.5;

s42, when K ₀ <K<K ₁ When the starting switch is pulled, the risk target analysis switch is positioned in the transformer substation, and the risk of N-1 power failure occurs, wherein K is ₁ The numerical value of (2) is set to 2.2-2.5;

s43, risk type judgment: when there is a risk of S41 or S42, if the bus coefficient between the minimum and maximum bus lines corresponding to the voltage levelIf the bus voltage level is equal to the highest voltage level of the station, the total stop risk of the N-1 bus is further determined; if->If the value is=0, then the N-1 parent is determined to existRisk of line blackout;

s44, counting the number N of power failure risks of the same voltage class bus N-1 of the same transformer substation, when n=n ₀ If so, correcting the risk type to be N-1 bus total stop risk, returning to S43, wherein N is ₀ The number of the buses is the voltage class; setting the bus interline operation value between the low-voltage buses with corresponding numbers of N-1 power failure risk buses to be 0;

s45, searching for risks of transformer substations at the receiving ends of the same voltage level, if the analysis and judgment result of the target switch shows that N-1 power failure risks exist in the transformer substations, selecting the switch with positive power directions on the corresponding bus as a starting switch, searching for an associated switch set, carrying out effective power supply path calculation, and judging that N-1 risk criteria exist as follows: k-1<K ₀ 。

3. The automatic radiation type power grid risk early warning method based on switch information according to claim 2, wherein the step S5 specifically comprises the following steps:

s51, taking the risk set obtained in the step S4 as a target, and enabling the power failure risk of the high-voltage bus N-1 to be equivalent to the power failure of the high-voltage total N-1 on the bus, and further equivalent to the power failure of the medium-voltage side and low-voltage side total switch N-1 corresponding to the main transformer, wherein the power failure risk criterion of the low-voltage bus is as follows: k (K)<K ₀ ；

S52, setting all line switches on the bus as starting switches with the middle and low voltage buses with the N-1 power failure risk in the step S51 as targets, repeating the step S4, and searching for a next-stage risk point;

s53, repeating the steps S4-S51 until the voltage level of the searched bus is 35kV or 10kV;

s54, carrying out load loss statistics, namely accumulating active power values of all outgoing lines at a sampling moment before target switch deflection or analog deflection by taking all 35kV and 10kV buses with power failure risks obtained through searching as targets, and obtaining the load loss S _Σ ；

S55, calculating the load loss proportion, and respectively calculating the load loss magnitude S of each region according to the load region attribute ₁ 、S ₂ 、S ₃ … …, and the loads of the respective regions at the same timeThe total amount is compared to obtain a load loss ratio S ₁ %、S ₂ %、S ₃ %、……。

4. The automatic risk early warning method for a radiation type power grid based on switch information according to claim 3, wherein the risk grading and early warning information issuing specifically comprises the following steps:

matching the N-1 risk event type with the load loss and the load loss proportion with a risk event library to perform risk grading, and generating early warning information;

and issuing power grid risk early warning through a D5000 system popup window.