Wide-Area Response-Based Transient Stability Online Prediction and Optimization Control System and Method

Abstract

The present invention discloses a transient stability online prediction and optimization control system based on wide-area response, which includes a control master station of the transient stability online prediction and optimization emergency control system based on wide-area response and N control slave stations of the transient stability online prediction and optimization emergency control system based on wide-area response; the control master station of the transient stability online prediction and optimization emergency control system based on wide-area response is respectively connected to the N control slave stations of the transient stability online prediction and optimization emergency control system based on wide-area response; it solves the technical problems in the prior art that the offline calculation workload of the security and stability control is large, it is almost impossible to accurately match the operating conditions of the actual system with the preset conditions, the strategy table must be recalculated and verified after the power grid structure changes, and when major changes occur in the power system, repetitive and cumbersome calculations and adjustments of the strategy table are required, and the operation and maintenance tasks are extremely heavy, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of power system stability control, and particularly relates to a transient stability online prediction and optimization control system and method based on wide-area response. Background Art

[0002] Regarding the impacts brought by the grid connection of large-scale small hydropower, wind power or photovoltaic power generation to the safety and stability of the power grid and the research and development of supporting stability control systems, some scholars at home and abroad have conducted a large number of studies on this. Through decades of accumulation of large power grid operation experience, China's power industry has formulated the "Guide for Safe and Stable Operation of Power Systems", established three lines of defense for the power grid, and ensured the safe and stable operation of China's power grid. Under the new situation, in order to cope with the impacts brought by the safety and stability of multiple energy sources dispersed into the regional power grid, it is necessary to strengthen the optimal allocation of controllable resources within the power grid, strengthen the coordination among the three lines of defense of the power system, and establish a safety and stability coordination system covering safety assessment, preventive control and emergency control. In recent years, many scholars have studied the coordination among power grid safety and stability control measures, including the coordinated control system and its control method of multiple control devices in the power system, and the integrated coordinated control method of large power grid safety and stability early warning, preventive control and emergency control.

[0003] However, the existing online pre-decision technologies mainly carry out relevant research work for large interconnected power systems, and there is still little research on the online safety and stability control technology for combined power generation systems containing multiple intermittent energy sources such as wind, light, large-scale small hydropower, and coalbed methane. The randomness and volatility of intermittent energy sources such as wind power and photovoltaic power generation, which have an impact on the safe and stable operation of the system, are not fully considered. Moreover, intermittent energy sources such as wind and light are different from conventional synchronous power generation technologies, and their unit types, unit controls, grid connection modes, etc. will bring a series of impacts on the formulation of safety and stability control strategies. Currently, the research on the safety and stability of multiple intermittent energy sources dispersed into the system mainly focuses on model establishment and stability analysis.

[0004] The safety and stability control system of the power system is one of the main measures to ensure the safe and stable operation of the power grid. The traditional safety and stability control system adopts the technical route of "offline calculation and online matching". Its disadvantages are that the offline calculation workload is large, it is almost impossible to accurately match the operating conditions of the actual system with the pre-set conditions, and the strategy table must be recalculated and checked after the power grid structure changes. Moreover, when major changes occur in the power system, repetitive and cumbersome calculations and adjustments of the strategy table are required, and the operation and maintenance tasks are very heavy. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a transient stability online prediction and optimization control system and method based on wide-area response, so as to solve the technical problems in the prior art that the offline calculation workload of the security and stability control is large, it is almost impossible to accurately match the operating conditions of the actual system with the pre-set conditions, the strategy table must be recalculated and verified after the power grid structure changes, and when major changes occur in the power system, repetitive and cumbersome calculations and adjustments of the strategy table are required, and the operation and maintenance tasks are extremely heavy.

[0006] The technical solution of the present invention:

[0007] A transient stability online prediction and optimization control system based on wide-area response, which includes a control master station and N control sub-stations; the control master station is respectively connected to the N control sub-stations; the N control sub-stations include: a wind power control sub-station, b photovoltaic control sub-stations, c small hydropower control sub-stations, d large hydropower control sub-stations, e thermal power control sub-stations, f local dispatching sub-stations, and g county dispatching sub-stations.

[0008] The wind power control sub-station, photovoltaic control sub-station, small hydropower control sub-station, large hydropower control sub-station, and thermal power control sub-station respectively include a stability control sub-station terminal, an in-station line protection and measurement and control device, an in-station regional power grid out-of-step splitting device, an in-station unit measurement and control device, an in-station bus measurement and control device, an in-station DC feeder panel, an in-station common measurement and control panel, and a digital distribution interface device; the stability control sub-station terminal is connected in series with the current loop of the in-station line protection and measurement and control device; the stability control sub-station terminal is connected in parallel with the voltage loop of the in-station line protection and measurement and control device; the stability control sub-station terminal is connected to the trip loop of the in-station line protection and measurement and control device or the in-station regional power grid out-of-step splitting device; the stability control sub-station terminal is connected to the in-station unit measurement and control device; the stability control sub-station terminal is connected in parallel with the voltage loop of the in-station bus measurement and control device; the stability control sub-station terminal is connected to the in-station DC feeder panel; the stability control sub-station terminal is connected to the in-station common measurement and control panel. The stability control sub-station terminal is connected to the communication interface device through an optical fiber, and the communication interface device is connected to the digital distribution interface device through a coaxial cable.

[0009] The local dispatching sub-station and the county dispatching sub-station respectively include: a stability control sub-station terminal, an in-station line protection and measurement and control device, an in-station bus measurement and control device, an in-station DC feeder panel, an in-station common measurement and control panel, and a digital distribution interface device; the stability control sub-station terminal is connected in series with the current loop of the in-station line protection and measurement and control device; the stability control sub-station terminal is connected in parallel with the voltage loop of the in-station line protection and measurement and control device; the stability control sub-station terminal is connected to the trip loop of the in-station line protection and measurement and control device; the stability control sub-station terminal is connected in parallel with the voltage loop of the in-station bus measurement and control device; the stability control sub-station terminal is connected to the in-station DC feeder panel; the stability control sub-station terminal is connected to the in-station common measurement and control panel; the stability control sub-station terminal is connected to the communication interface device through an optical fiber, and the communication interface device is connected to the digital distribution interface device through a coaxial cable.

[0010] The control master station includes a stability control master station device, an in-station common measurement and control panel, an in-station DC feeder panel, a digital distribution interface device, a stability control communication interface device, and a telecontrol dedicated line router; the stability control master station device is connected to the in-station common measurement and control panel; the stability control master station device is connected to the in-station DC feeder panel; the stability control master station device is connected to the communication interface device through a tail fiber; the stability control master station device is connected to the stability control communication interface device through an optical fiber.

[0011] The control method of the transient stability online prediction and optimization control system based on wide-area response includes:

[0012] Step 1, N control sub-stations upload the collected power grid operation information to the control master station;

[0013] Step 2, set the voltage instability criterion threshold Vξ of the power grid, the integral threshold Aμ for real-time acquisition of wide-area voltage values, the lowest threshold V L of the unstable voltage trajectory swing voltage and the termination threshold A set of the unstable voltage integral;

[0014] Step 3, through the real-time obtained power grid operation information, extract the wide-area voltage information of the power grid, and compare it with the voltage instability criterion threshold Vξ of the power grid. If the real-time acquired wide-area voltage value V(t) of the power grid is less than or equal to the voltage instability criterion threshold Vξ of the power grid, it is judged that the power grid is in a stable state; if the real-time acquired wide-area voltage value V(t) of the power grid is greater than the voltage instability criterion threshold Vξ of the power grid, go to Step 4;

[0015] Step 4, calculate the integral value A of the real-time acquired wide-area voltage value V(t), and compare it with the integral threshold Aμ of the real-time acquired wide-area voltage value. If the integral value A of the real-time acquired wide-area voltage value V(t) is greater than or equal to the integral threshold Aμ of the real-time acquired wide-area voltage value, return to Step 1; if the integral value A of the real-time acquired wide-area voltage value V(t) is less than the integral threshold Aμ of the real-time acquired wide-area voltage value, go to Step 5;

[0016] Step 5, judge whether the voltage is in the allowable fluctuation stage. When the criterion condition is met, return to Step 1; when the criterion condition is not met, it is considered to be in the allowable fluctuation stage and go to Step 6;

[0017] Step 6, obtain the real-time acquired wide-area voltage value V2(t) of the power grid, and compare it with the non-standard voltage reference value V u . When the real-time acquired wide-area voltage value V2(t) of the power grid is greater than or equal to the non-standard voltage reference value V u , if within a continuous βT time, V2(t) is greater than V u , it is judged that the system is transiently stable. Within a continuous βT time, V2(t) is not completely greater than or equal to V u, it is determined that there is a situation of relatively low local voltage in the system. When the real-time wide-area voltage value V2(t) of the power grid is less than the non-standard voltage reference value V u , then it proceeds to Step 7;

[0018] Step 7: Calculate the voltage integral value A p , and compare A P with the lowest threshold voltage V of the unstable voltage trajectory swing L . When A P is less than the lowest threshold voltage V of the unstable voltage trajectory swing L , then take the value of A q = A p , and enter Step 8 for calculation; when A P is greater than or equal to the lowest threshold voltage V of the unstable voltage trajectory swing L , calculate the voltage integral value A q , and enter Step 8;

[0019] Step 8: Compare A q with the termination threshold value A of the unstable voltage integral set . When A q is less than the termination threshold value A of the unstable voltage integral set , then return to Step 6 for recalculation; when A q is greater than or equal to the termination threshold value A of the unstable voltage integral set , then it is determined that the system is transiently unstable and enters Step 9;

[0020] Step 9: When the master station system determines that the system is unstable, it issues a stable control device action to the control substation corresponding to V2(t) for generator tripping or load shedding.

[0021] The power grid operation information described in Step 1 includes the three-phase current values, three-phase voltage values and frequency information of the lines, the operation switch quantity information of the lines, the operation conditions of the units and the information of the units that can be tripped, the operation information of the units, and the three-phase voltage values and frequency information of all busbars of all voltage levels in the station.

[0022] The formula for calculating the integral value A of the real-time wide-area voltage value V(t) described in Step 4 is:

[0023]

[0024] In formula (1), A is the integral value of the real-time wide-area voltage value V(t), t0 is the initial value of the integral time of the real-time wide-area voltage value V(t); t end is the termination value of the integral time of the real-time wide-area voltage value V(t); V u is the non-standard voltage reference value, that is, the starting voltage of the integral.

[0025] The formula for determining whether the voltage is in the allowable fluctuation stage described in Step 5 is:

[0026]

[0027] Where: ΔV(t) = V(t) - V(t - T), T is the sampling time, and V(t - T) is the voltage value at the previous sampling moment; when |ΔV(t)| - |ΔV(t - T)| does not meet the criterion condition of formula (2), it is considered the allowable fluctuation stage.

[0028] Calculate the voltage integral value A p And the formula for calculating the voltage integral value A q is as follows:

[0029]

[0030]

[0031] Advantages of the present invention

[0032] The present invention provides a transient stability online prediction and optimization control system and method based on wide-area response. By constructing a transient stability online prediction and optimization emergency control system based on wide-area response including a control master station and wind power control sub-stations, photovoltaic control sub-stations, small hydropower control sub-stations, large hydropower control sub-stations, thermal power control sub-stations, sub-stations controlled by local power grids, and sub-stations controlled by county-level power grids, there is no need to formulate a control strategy set according to off-line calculations. Electrical quantities and switch quantities of the control sub-stations are uploaded to the control master station for on-line calculations, and are judged on-line with indicators such as the voltage instability criterion threshold Vξ of the power grid, the integral threshold Aμ of the real-time collected wide-area voltage value, the lowest threshold V of the swing voltage of the unstable voltage trajectory, and the termination threshold A of the unstable voltage integral. L and the termination threshold A of the unstable voltage integral set etc. It solves the technical problems in the prior art, such as the large workload of off-line calculations for safety and stability control, the almost impossible precise matching between the operating conditions of the actual system and the pre-set conditions, the necessity to recalculate and check the strategy table after the power grid structure changes, and the need for repeated and cumbersome calculations and adjustments of the strategy table when major changes occur in the power system, resulting in a very heavy operation and maintenance task. Brief description of the drawings

[0033] Figure 1 It is a schematic connection structure diagram of the control master station and the control sub-stations;

[0034] Figure 2 It is a schematic structure diagram of the photovoltaic, wind power, small hydropower, large hydropower, and thermal power control sub-stations;

[0035] Figure 3 It is a schematic structure diagram of the sub-stations controlled by local power grids and county-level power grids;

[0036] Figure 4It is a schematic diagram of the control method flow. Specific implementation mode

[0037] A transient stability online prediction and optimized emergency control system based on wide-area response, which includes a control master station and N control sub-stations.

[0038] (1) Among them, the N control sub-stations include a wind power control sub-stations, b photovoltaic control sub-stations, c small hydropower control sub-stations, d large hydropower control sub-stations, e thermal power control sub-stations, f local power grid sub-stations, and g county power grid sub-stations.

[0039] Among them, a + b + c + d + e + f + g = N.

[0040] (2) Among them, a wind power control sub-stations, b photovoltaic control sub-stations, c small hydropower control sub-stations, d large hydropower control sub-stations, e thermal power control sub-stations, each control sub-station includes a stability control sub-station terminal within the control sub-station, as well as an in-station line protection and measurement and control device, an in-station regional power grid out-of-step splitting device, an in-station unit measurement and control device, an in-station bus measurement and control device, an in-station DC feeder panel, an in-station common measurement and control panel, a digital distribution interface device, etc.;

[0041] The stability control sub-station terminal is connected in series with the current loop of the in-station line protection and measurement and control device for collecting the three-phase current values of the line;

[0042] The stability control sub-station terminal is connected in parallel with the voltage loop of the in-station line protection and measurement and control device for collecting the three-phase voltage values and frequency information of the line;

[0043] The stability control sub-station terminal is connected to the trip circuit of the in-station line protection and measurement and control device or the in-station regional power grid out-of-step splitting device for issuing a generator tripping command and obtaining the operating switch quantity information of the line;

[0044] The stability control sub-station terminal is connected to the in-station unit measurement and control device for collecting the unit operating conditions and cuttable unit information, and unit operating information; the unit operating information includes voltage, current, power, power angle, and frequency.

[0045] The stability control sub-station terminal is connected in parallel with the voltage loop of the in-station bus measurement and control device for collecting the three-phase voltage values and frequency information of all voltage levels of the in-station bus;

[0046] The stability control sub-station terminal is connected to the in-station DC feeder panel for obtaining the device power supply of the stability control sub-station terminal;

[0047] The stability control sub-station terminal is connected to the in-station common measurement and control panel for transmitting the locking of the in-station PMU device, the abnormality of the in-station PMU device, the locking of the stability control sub-station terminal, the alarm of the stability control sub-station terminal, the locking of the stability control sub-station terminal, the action of the stability control sub-station terminal, and the channel alarm of the stability control sub-station terminal.

[0048] The stability control substation terminal is connected to the communication interface device through an optical fiber cable, and the communication interface device is connected to the digital distribution interface device through a coaxial cable, which is used for interactive transmission of information with the control master station of the wide-area response-based transient stability online prediction and optimized emergency control system.

[0049] (3) Among them, there are f local dispatching substation control substations and g county dispatching substation control substations. Each control substation includes a stability control substation terminal within the control substation, as well as in-station line protection and measurement and control devices, in-station bus measurement and control devices, in-station DC feeder panels, in-station common measurement and control panels, digital distribution interface devices, etc.;

[0050] The stability control substation terminal is connected in series with the current loop of the in-station line protection and measurement and control device, which is used for collecting the three-phase current values of the line;

[0051] The stability control substation terminal is connected in parallel with the voltage loop of the in-station line protection and measurement and control device, which is used for collecting the three-phase voltage values and frequency information of the line;

[0052] The stability control substation terminal is connected to the trip circuit of the in-station line protection and measurement and control device, which is used for issuing generator tripping or load shedding commands and obtaining the operating switch quantity information of the line;

[0053] The stability control substation terminal is connected in parallel with the voltage loop of the in-station bus measurement and control device, which is used for collecting the three-phase voltage values and frequency information of all voltage level buses in the station;

[0054] The stability control substation terminal is connected to the in-station DC feeder panel, which is used for obtaining the device power supply of the stability control substation terminal;

[0055] The stability control substation terminal is connected to the in-station common measurement and control panel, which is used for transmitting the locking of the in-station PMU device, the abnormality of the in-station PMU device, the locking of the stability control substation terminal, the alarm of the stability control substation terminal, the locking of the stability control substation terminal, the action of the stability control substation terminal, and the channel alarm of the stability control substation terminal.

[0056] The stability control substation terminal is connected to the communication interface device through an optical fiber cable, and the communication interface device is connected to the digital distribution interface device through a coaxial cable, which is used for interactive transmission of information with the control master station of the wide-area response-based transient stability online prediction and optimized emergency control system.

[0057] (4) Among them, the control master station includes a stability control master station device, an in-station common measurement and control panel, an in-station DC feeder panel, a digital distribution interface device, a stability control communication interface device, and a telecontrol dedicated line router.

[0058] The stability control master station device is connected to the in-station common measurement and control panel, which is used for transmitting the alarm of the stability control master station device, the locking of the stability control master station device, the action of the stability control master station device, and the channel alarm of the stability control master station device.

[0059] The stability control master station device is connected to the in-station DC feeder panel and is used to obtain the device power supply of the stability control master station device;

[0060] The stability control master station device is connected to the communication interface device through an optical fiber pigtail. The communication interface device is connected to the digital distribution interface device through a coaxial cable and is used to interactively transmit information with the control sub-station of the wide-area response-based transient stability online prediction and optimization emergency control system.

[0061] The stability control master station device is connected to the stability control communication interface device through an optical fiber. The stability control communication interface device is connected to the remote control dedicated line router in the regional power grid optical transmission equipment panel through a network cable and is used to interactively transmit information with the monitoring master stations of the local dispatching and county dispatching.

[0062] The control method of the wide-area response-based transient stability online prediction and optimization control system includes:

[0063] Step 1: N control sub-stations upload the collected power grid operation information to the control master station;

[0064] The power grid operation information in Step 1 includes the three-phase current values, three-phase voltage values and frequency information of the lines, the operating switch quantity information of the lines, the operating conditions of the units and the information of the units that can be cut, the operating information of the units, and the three-phase voltage values and frequency information of all voltage-level busbars in the station.

[0065] Step 2: Set the voltage instability criterion threshold Vξ of the power grid, the integral threshold Aμ for real-time acquisition of the wide-area voltage value, the lowest threshold V of the swing voltage of the unstable voltage trajectory L and the integral termination threshold A of the unstable voltage set ;

[0066] Step 3: Through the real-time obtained power grid operation information, extract the wide-area voltage information of the power grid and compare it with the voltage instability criterion threshold Vξ of the power grid. If the real-time acquired wide-area voltage value V(t) of the power grid is less than or equal to the voltage instability criterion threshold Vξ of the power grid, it is judged that the power grid is in a stable state; if the real-time acquired wide-area voltage value V(t) of the power grid is greater than the voltage instability criterion threshold Vξ of the power grid, go to Step 4;

[0067] Step 4: Calculate the integral value A of the real-time acquired wide-area voltage value V(t) and compare it with the integral threshold Aμ of the real-time acquired wide-area voltage value. If the integral value A of the real-time acquired wide-area voltage value V(t) is greater than or equal to the integral threshold Aμ of the real-time acquired wide-area voltage value, return to Step 1; if the integral value A of the real-time acquired wide-area voltage value V(t) is less than the integral threshold Aμ of the real-time acquired wide-area voltage value, go to Step 5;

[0068] The formula for calculating the integral value A of the real-time acquired wide-area voltage value V(t) in Step 4 is:

[0069]

[0070] In formula (1), A is the integral value of the real-time collected wide-area voltage value V(t), t0 is the initial value of the integral time of the real-time collected wide-area voltage value V(t); t end is the termination value of the integral time of the real-time collected wide-area voltage value V(t); V u is the non-standard voltage reference value, that is, the starting voltage of the integral.

[0071] Step 5: Determine whether the voltage is in the allowable fluctuation stage. When the criterion condition is met, return to Step 1; when the criterion condition is not met, it is considered to be in the allowable fluctuation stage, and go to Step 6;

[0072] The formula for determining whether the voltage is in the allowable fluctuation stage described in Step 5 is:

[0073]

[0074] In the formula: ΔV(t) = V(t) - V(t - T), T is the sampling time, and V(t - T) is the voltage value at the previous sampling moment; when |ΔV(t)| - |ΔV(t - T)| does not meet the criterion condition of formula (2), it is considered to be in the allowable fluctuation stage.

[0075] Step 6: Obtain the real-time collected wide-area voltage value V2(t) of the power grid and compare it with the non-standard voltage reference value V u When the real-time collected wide-area voltage value V2(t) of the power grid is greater than or equal to the non-standard voltage reference value V u If within a continuous βT time, V2(t) is greater than V u , it is determined that the system is transiently stable. If within a continuous βT time, V2(t) is not completely greater than or equal to V u , it is determined that there is a local low voltage situation in the system. When the real-time collected wide-area voltage value V2(t) of the power grid is less than the non-standard voltage reference value V u , go to Step 7;

[0076] Step 7: Calculate the voltage integral value A p , and compare A P with the lowest threshold value V L of the swing voltage of the unstable voltage trajectory. When A P is less than the lowest threshold value V L of the swing voltage of the unstable voltage trajectory, take A q = A p , and enter Step 8 for calculation; when A P is greater than or equal to the lowest threshold value V L of the swing voltage of the unstable voltage trajectory, calculate the voltage integral value A q , and enter Step 8;

[0077] Calculate the voltage integral value A p and calculate the voltage integral value A q The formula is as follows:

[0078]

[0079]

[0080] Step 8: Compare A q with the instability voltage integral termination threshold value A set When A q is less than the instability voltage integral termination threshold value A set , return to Step 6 for recalculation; when A q is greater than or equal to the instability voltage integral termination threshold value A se t, it is determined that the system is transiently unstable and proceed to Step 9;

[0081] Step 9: When the control master station determines that the system is unstable, send a stable control device action to the control substation corresponding to V2(t) for generator tripping or load shedding.

Claims

1. A control method for a transient stability online prediction and optimization control system based on wide-area response, characterized in that: The system includes a control master station and N control sub-stations; The control master station is respectively connected to the N control sub-stations; The N control sub-stations include: a wind power control sub-station, b photovoltaic control sub-stations, c small hydropower control sub-stations, d large hydropower control sub-stations, e thermal power control sub-stations, f local dispatching sub-stations, and g county dispatching sub-stations; The control method includes: Step 1: The N control sub-stations upload the collected power grid operation information to the control master station; Step 2: Set the voltage instability criterion threshold Vξ of the power grid, the integral threshold Aμ for real-time acquisition of wide-area voltage values, the lowest threshold V of the swing voltage of the unstable voltage trajectory L and the termination threshold A of the unstable voltage integral set ; Step 3: Through the real-time obtained power grid operation information, extract the wide-area voltage information of the power grid, and compare it with the voltage instability criterion threshold Vξ of the power grid. If the real-time collected wide-area voltage value V(t) of the power grid is less than or equal to the voltage instability criterion threshold Vξ of the power grid, it is judged that the power grid is in a stable state; If the real-time collected wide-area voltage value V(t) of the power grid is greater than the voltage instability criterion threshold Vξ of the power grid, then go to Step 4; Step 4: Calculate the integral value A of the real-time collected wide-area voltage value V(t), and compare it with the integral threshold Aμ of the real-time collected wide-area voltage value. If the integral value A of the real-time collected wide-area voltage value V(t) is greater than or equal to the integral threshold Aμ of the real-time collected wide-area voltage value, return to Step 1; If the integral value A of the real-time collected wide-area voltage value V(t) is less than the integral threshold Aμ of the real-time collected wide-area voltage value, then go to Step 5; Step 5: Judge whether the voltage is in the allowable fluctuation stage. When the criterion condition is met, return to Step 1; When the criterion condition is not met, it is considered to be in the allowable fluctuation stage, and go to Step 6; Step 6: Obtain the real-time wide-area voltage value V2(t) of the power grid and compare it with the non-standard voltage reference value V u When the real-time wide-area voltage value V2(t) of the power grid is greater than or equal to the non-standard voltage reference value V u If within a continuous βT time period, V2(t) is greater than V u , it is determined that the system is transiently stable. If within a continuous βT time period, V2(t) is not completely greater than or equal to V u , it is determined that there is a local low voltage condition in the system. When the real-time wide-area voltage value V2(t) of the power grid is less than the non-standard voltage reference value V u , then proceed to Step 7; Step 7, calculate the voltage integral value A p , and compare A P with the lowest threshold value V of the swing voltage of the voltage instability trajectory L . When A P is less than the lowest threshold value V of the swing voltage of the voltage instability trajectory L , then take the value A q = A p , and proceed to step 8 for calculation; when A P is greater than or equal to the lowest threshold value V of the swing voltage of the voltage instability trajectory L , calculate the voltage integral value A q , and enter step 8; Step 8: Take A q and compare it with the instability voltage integration termination threshold value A set . When A q is less than the instability voltage integration termination threshold value A set , return to Step 6 for recalculation; when A q is greater than or equal to the instability voltage integration termination threshold value A set , it is determined that the system is transiently unstable and proceed to Step 9; Step 9: When the master station system judges that the system is unstable, send a stable control device action to the control sub-station corresponding to V2(t) for generator tripping or load shedding.

2. The control method of a transient stability online prediction and optimization control system based on wide-area response according to claim 1, characterized in that: The wind power control sub-station, photovoltaic control sub-station, small hydropower control sub-station, large hydropower control sub-station, and thermal power control sub-station respectively include a stable control sub-station terminal, an in-station line protection and measurement and control device, an in-station regional power grid out-of-step splitting device, an in-station unit measurement and control device, an in-station bus measurement and control device, an in-station DC feeder panel, an in-station common measurement and control panel, and a digital distribution interface device; The stable control sub-station terminal is connected in series with the current loop of the in-station line protection and measurement and control device; The stable control sub-station terminal is connected in parallel with the voltage loop of the in-station line protection and measurement and control device; The stable control sub-station terminal is connected to the trip loop of the in-station line protection and measurement and control device or the in-station regional power grid out-of-step splitting device; The stable control sub-station terminal is connected to the in-station unit measurement and control device; The stable control sub-station terminal is connected in parallel with the voltage loop of the in-station bus measurement and control device; The stable control sub-station terminal is connected to the in-station DC feeder panel; The stable control sub-station terminal is connected to the in-station common measurement and control panel; The stable control sub-station terminal is connected to the communication interface device through an optical fiber pigtail, and the communication interface device is connected to the digital distribution interface device through a coaxial cable.

3. The control method of a transient stability online prediction and optimization control system based on wide-area response according to claim 1, characterized in that: The sub-control stations of the regional dispatching substation and the county dispatching substation respectively include: a stability control substation terminal, an in-station line protection and measurement and control device, an in-station bus measurement and control device, an in-station DC feeder panel, an in-station common measurement and control panel, and a digital distribution interface device; the stability control substation terminal is connected in series with the current loop of the in-station line protection and measurement and control device; the stability control substation terminal is connected in parallel with the voltage loop of the in-station line protection and measurement and control device; the stability control substation terminal is connected to the trip loop of the in-station line protection and measurement and control device; the stability control substation terminal is connected in parallel with the voltage loop of the in-station bus measurement and control device; the stability control substation terminal is connected to the in-station DC feeder panel; the stability control substation terminal is connected to the in-station common measurement and control panel; the stability control substation terminal is connected to the communication interface device through an optical fiber ribbon, and the communication interface device is connected to the digital distribution interface device through a coaxial cable.

4. The control method of a transient stability online prediction and optimization control system based on wide-area response according to claim 1, characterized in that: The main control station includes a stability control main station device, an in-station common measurement and control panel, an in-station DC feeder panel, a digital distribution interface device, a stability control communication interface device, and a remote control dedicated line router; the stability control main station device is connected to the in-station common measurement and control panel; the stability control main station device is connected to the in-station DC feeder panel; the stability control main station device is connected to the communication interface device through an optical fiber ribbon; the stability control main station device is connected to the stability control communication interface device through an optical fiber.

5. The control method of a transient stability online prediction and optimization control system based on wide-area response according to claim 1, characterized in that: The grid operation information described in step 1 includes the three-phase current value, three-phase voltage value and frequency information of the line, the operation switching quantity information of the line, the operation conditions of the units and the information of the units that can be cut, the operation information of the units, and the three-phase voltage value and frequency information of all voltage levels of the buses in the station.

6. The control method of a transient stability online prediction and optimization control system based on wide-area response according to claim 1, characterized in that: The formula for calculating the integral value A of the real-time collected wide-area voltage value V(t) in step 4 is: In formula (1), A is the integral value of the real-time collected wide-area voltage value V(t), and t0 is the initial value of the integral time of the real-time collected wide-area voltage value V(t); t end is the termination value of the integration time for real-time acquisition of the wide-area voltage value V(t); V u is a non-standard voltage reference value, i.e., the starting voltage of integration.

7. The control method of a transient stability online prediction and optimization control system based on wide-area response according to claim 1, characterized in that: The formula for judging whether the voltage is in the allowable fluctuation stage in step 5 is: Where: ΔV(t) = V(t) - V(t - T), T is the sampling time, and V(t - T) is the voltage value at the previous sampling moment; when |ΔV(t)| - |ΔV(t - T)| does not meet the criterion condition of formula (2), it is considered to be in the allowable fluctuation stage.

8. The control method of a transient stability online prediction and optimization control system based on wide-area response according to claim 1, characterized in that: Calculate the voltage integral value A p and the formula for calculating the voltage integral value A q is as follows: t end is the termination value of the integration time for real-time acquisition of wide-area voltage values; t0 is the initial value of the integration time for real-time acquisition of wide-area voltage values; V u is the non-standard voltage reference value, i.e., the starting voltage of integration; V(t) is the real-time acquired wide-area voltage value; V(t - T) is the voltage value at the previous sampling moment; T is the sampling time; V L is the lowest threshold value of the swing voltage of the unstable voltage trajectory; A p is the voltage integral value.

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