CN107732951B

CN107732951B - Multi-resource coordination control method and device for direct current blocking fault impact alternating current channel

Info

Publication number: CN107732951B
Application number: CN201710902265.4A
Authority: CN
Inventors: 陈得治; 袁森; 罗亚洲; 马世英; 宋云亭; 贾琳; 王青; 訾鹏; 张晨; 李轶群; 李再华; 李媛媛; 郑超; 吴丽华; 张鑫; 申旭辉; 张志强; 李立新; 袁珩迪
Original assignee: State Grid Corp of China SGCC; China Electric Power Research Institute Co Ltd CEPRI; North China Grid Co Ltd; State Grid Shanghai Electric Power Co Ltd
Current assignee: State Grid Corp of China SGCC; China Electric Power Research Institute Co Ltd CEPRI; North China Grid Co Ltd; State Grid Shanghai Electric Power Co Ltd
Priority date: 2017-09-29
Filing date: 2017-09-29
Publication date: 2021-04-30
Anticipated expiration: 2037-09-29
Also published as: CN107732951A

Abstract

The invention provides a multi-resource coordination control method and a multi-resource coordination control device for a direct current blocking fault impact alternating current channel. The technical scheme provided by the invention comprehensively considers the pumping storage cut pump, the direct current power emergency modulation, the accurate load cutting and the cut load multi-type control resources, enriches the control means, optimizes the objective function of the multi-resource coordination control model by minimizing the cut load amount, considers the constraint condition, improves the control effectiveness, reduces the control cost and improves the power grid defense performance; in addition, a heuristic algorithm is adopted to obtain a multi-resource coordination control sequence and a multi-resource coordination control quantity, and the multi-resource coordination control quantity obtained through the heuristic algorithm is strong in interpretability and has better practicability.

Description

Multi-resource coordination control method and device for direct current blocking fault impact alternating current channel

Technical Field

The invention relates to the technical field of extra-high voltage direct current, in particular to a multi-resource coordination control method and device for a direct current blocking fault impact alternating current channel.

Background

With the gradual construction and operation of high-capacity extra-high voltage direct current, China has formed a larger-scale area interconnection power system, but in the construction transition period, compared with the strong direct current, the situations that an alternating current channel is relatively weak and the like still exist. In the future, a plurality of extra-high voltage direct currents are fed into the power grid, and some extra-high voltage alternating current connection sections are relatively weak, so that the whole power grid has the characteristics of strong direct current and weak alternating current. If a direct current blocking fault occurs, large-scale tidal current transfer is caused, and the more stable limit of a weak alternating current channel is, the more transient instability of a power grid occurs, so that the safe and stable operation of the power grid is influenced.

The operation of multiple extra-high voltage direct currents enables the mode that a weak alternating current channel is impacted to become more complex and changeable; meanwhile, multiple direct currents are fed in intensively, the possibility that the multiple direct currents are locked in succession or simultaneously exists, the impact degree is increased, and the control difficulty and the control cost are further increased. At present, there are many control researches on dealing with direct current blocking faults, and document [1] researches and develops an effective algorithm for reasonably distributing total shedding amount to each execution station aiming at the problem of distribution of total shedding load safety control amount after a power grid has a serious fault. Document [2] takes an interconnection system comprising a plurality of direct-current transmission channels as a research object, and provides a safety control device action strategy after a single channel fault based on the characteristic of rapid power modulation of a high-voltage direct-current system, wherein the strategy considers constraint conditions such as power grid stability and unit output, and ensures that the unit modulation power is minimum through other direct-current conversion band loss power. Although the above documents can deal with the safe and stable control of strong direct current impact weak alternating current channels, the following disadvantages still exist:

(1) the method focuses on single safe and stable control means such as a generator tripping, load shedding, direct current modulation and the like, but the energy of a multi-direct current impact weak alternating current channel is large, the influence on a power grid is wide, and the problems of insufficient effectiveness, overlarge prevention and control cost and the like exist in conventional and single-resource prevention and control;

(2) the safe and stable control resources for preventing and controlling the problems are not thoroughly carded, and available control resources are not completely covered in the existing coordination control research considering multiple resources;

(3) solving the resource control model mostly depends on a complex mathematical method, the physical meaning of the obtained control solution is not good enough, and the practicability needs to be further improved;

(4) at present, a multi-resource coordination control model which is relatively comprehensive and is used for solving the instability problem caused by strong direct current impact on a weak alternating current channel is not available.

Document [1] chenxinghua, wu xinxin, wu national third, etc. safety and stability control system load shedding amount allocation algorithm [ J ] relay, 2007, 35 (11): 26-29.

Document [2] von leisurely, chenggang, surge, etc. modulation strategy of grid safety control device after failure of high voltage direct current transmission system [ J ] grid technology, 2012, 36 (9): 88-94.

Disclosure of Invention

In order to overcome the defects of insufficient single resource effectiveness and excessive prevention and control cost in the prior art, the invention provides a multi-resource coordination control method and a device for impacting an alternating current channel by a direct current blocking fault, wherein the static stability limit of the alternating current channel is determined firstly; then determining a multi-resource coordination control sequence and a coordination control quantity according to the multi-resource coordination control model meeting the constraint conditions; the multi-resource coordination control model comprises an objective function constructed by taking the minimum load shedding amount as a target, and the constraint condition is determined according to the static stability limit of the alternating current channel; and finally, realizing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity.

In order to achieve the purpose of the invention, the invention adopts the following technical scheme:

the invention provides a multi-resource coordination control method for a direct current blocking fault impact alternating current channel, which comprises the following steps:

determining a static stability limit of an alternating current channel;

determining a multi-resource coordination control sequence and a coordination control quantity according to a multi-resource coordination control model meeting constraint conditions; the multi-resource coordination control model comprises an objective function constructed by taking the minimum load shedding amount as a target, and the constraint condition is determined according to the static stability limit of the alternating current channel;

and performing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity.

The determining the static stability limit of the alternating current channel comprises:

setting the static active power of an alternating current channel to be 0, and simulating the direct current blocking fault based on a steady-state power flow model and an electromechanical transient model to obtain a power angle curve of a generator relative to a reference machine and an out-of-step oscillation center of a strong weak alternating current power grid;

judging whether the following two conditions are met simultaneously:

1) the power angle of the generator relative to the reference machine is larger than 360 degrees, and the generator and the reference machine are respectively positioned on two sides of the alternating current channel;

2) the out-of-step oscillation center of the strong direct current and weak alternating current power grid falls on the weak alternating current channel;

if so, the alternating current channel reaches a static stability limit, a dynamic active power peak value of the alternating current channel at the static stability limit is recorded, and the dynamic active power peak value of the alternating current channel at the static stability limit is taken as the static stability limit of the alternating current channel; otherwise, the static active power of the alternating current channel is increased by 50MW, the simulation of the direct current blocking fault is carried out based on the steady-state power flow model and the electromechanical transient model, and the follow-up operation is executed.

The objective function is as follows:

F＝min P_fh (1)

wherein F represents an objective function, P_fhThe amount of load cut is indicated.

The constraint conditions comprise inequality constraint of a weak alternating current channel in a static stability limit, inequality constraint of an element in a thermal stability limit, inequality constraint of bus voltage in an upper and lower limit range, upper and lower limit constraint of pumping and storage switching pump capacity, upper and lower limit constraint of direct current power emergency modulation capacity, upper and lower limit constraint of accurate load cutting capacity and upper and lower limit constraint of load cutting capacity.

The inequality constraint of the weak AC channel within the static stability limit is as follows:

S₀-ΔS(P_cx,P_d,P_jz,P_fh)≤S_lim (2)

wherein S is₀For the dynamic active power peak, S, of the AC channel after a DC blocking fault_limΔ S (P) which is the static stability limit of the AC channel_cx,P_d,P_jz,P_fh) For dynamic active power peak change of AC channel, P_cxFor pumping the pump volume, P_dFor emergency modulation of DC power, P_jzFor precise load shedding, P_fhFor load shedding, cx represents pumping and pump shedding resources, d represents direct current power emergency modulation resources, jz represents accurate load shedding resources, and fh represents load shedding resources;

the inequality constraint of the element within the thermal stability limits is as follows:

P_s,0+ΔP_s(P_cx,P_d,P_jz,P_fh)≤P_s,max (3)

P_c,0+ΔP_c(P_cx,P_d,P_jz,P_fh)≤P_c,max (4)

wherein, P_s,0For saving the initial active power of the elements in the vicinity of the interruption, P_s,maxFor saving the thermal stability limit of the element in the vicinity of the interface, Δ P_s(P_cx,P_d,P_jz,P_fh) Is the active power change of the element in the adjacent region of the provincial section; p_c,0To controlInitial active power, P, of components in the vicinity of the manufacturing site_c,maxFor controlling the thermal stability limit of the elements in the near-field of the site, Δ P_c(P_cx,P_d,P_jz,P_fh) An active power change amount for an element in a near zone of a control site;

the inequality constraint of the bus voltage in the upper and lower limit ranges is as follows:

U_s,min≤U_s,0+ΔU_s(P_cx,P_d,P_jz,P_fh)≤U_s,max (5)

U_c,min≤U_c,0+ΔU_c(P_cx,P_d,P_jz,P_fh)≤U_c,max (6)

wherein, U_s,minAnd U_s,maxLower and upper limits, U, of the bus voltage in the vicinity of the economizer section, respectively_s,0For the initial voltage of the busbar in the vicinity of the saving section, Δ U_s(P_cx,P_d,P_jz,P_fh) The change quantity of the bus voltage in the adjacent area of the provincial section; u shape_c,minAnd U_c,maxLower and upper limits, U, respectively, of the bus voltage in the vicinity of the control location_c,0For controlling the initial voltage of the busbar in the vicinity of the site, Δ U_c(P_cx,P_d,P_jz,P_fh) For controlling the bus voltage variation in the near zone;

the upper limit and the lower limit of the pumping and storage cutting pump amount are constrained as follows:

0≤P_cx≤P_cx,max (7)

wherein, P_cx,maxThe upper limit of the pumping and storage switching pump;

the upper and lower limits of the direct current power emergency modulation quantity are constrained as follows:

0≤P_d≤P_d,max (8)

wherein, P_d,maxIs the upper limit of the DC power emergency modulation, when the DC power emergency modulation is the speed-increasing modulation, P_d,maxThe upper limit of the direct current power is increased rapidly, and the value is 10 percent P_d,e(ii) a When the emergency modulation of the DC power is the speed drop modulation, P_d,maxThe upper limit of the emergency modulation of the direct current power is 90 percent P_d,e，P_d,eActive power delivered to the dc transmission system;

the upper limit and the lower limit of the accurate load cutting amount are constrained as follows:

0≤P_jz≤P_jz,max (9)

wherein, P_jz,maxThe upper limit of the precise load shedding;

the upper and lower limits of the load shedding amount are constrained as follows:

0≤P_fh≤P_fh,max (10)

wherein, P_fh,maxThe upper limit of the shear load.

The determining the multi-resource coordination control sequence and the coordination control quantity according to the multi-resource coordination control model meeting the constraint conditions comprises the following steps:

solving the objective function by adopting a heuristic algorithm to obtain the following multi-resource coordination control sequence:

the priority of a pumping storage switching pump, direct current power emergency modulation, accurate load switching and load switching is sequentially changed from high to low;

and obtaining the coordination control quantity of the pumping and storage switching pump, the direct current power emergency modulation, the accurate load switching and the load switching according to the coordination control sequence of the pumping and storage switching pump, the direct current power emergency modulation, the accurate load switching and the load switching.

Obtaining the coordinated control quantity of the pumping and cutting pump according to the coordinated control sequence of the pumping and cutting pump, the direct-current power emergency modulation, the accurate cutting load and the cutting load comprises the following steps:

let P_d、P_jz、P_fhAnd the initial value of the pumping amount is 0, and is increased by P according to the step length of the pumping amount_cxAt this time P_cx＝P_cx,0+μ_cx，P_cx,0To take the initial value of the pumping amount, mu_cxThe step length of the pumping storage cut pump;

checking P_cxIf equation (7) is satisfied, and if equation (7) is not satisfied, the coordinated control amount P 'of the pumping/storage pump'_cx＝P_cx-μ_cx(ii) a Otherwise checking P_cxWhether or not the formulas (3) to (6) are satisfied at the same time;

if P_cxDo not simultaneously satisfy the formulas (3) - (6), P'_cx＝P_cx-μ_cx(ii) a Otherwise checking P_cxWhether formula (2) is satisfied;

if P_cxSatisfy formula (2), P'_cx＝P_cxCoordinated control quantity P 'for emergency modulation of DC power'_dAnd a coordinated control quantity P 'of a precise load cutting'_jzControl amount P 'coordinated with cutting load'_fhAre all 0; otherwise, the pumping and storage switching pump amount at the moment is made to be P_cx,0And returning to increase P according to the step length of the pumping and cutting pump_cxAnd performing subsequent operations until P 'is obtained'_cx。

The method for obtaining the coordination control quantity of the direct current power emergency modulation according to the coordination control sequence of the pumping storage switching pump, the direct current power emergency modulation, the accurate load switching and the load switching comprises the following steps:

let P_jz、P_fhAnd the initial value of the direct current power emergency modulation quantity is 0, and the step length of the direct current power emergency modulation quantity is increased by P_dAt this time P_d＝P_d,0+μ_d，P_d,0Is an initial value of the DC power emergency modulation quantity, mu_dStep length for emergency modulation of direct current power;

checking P_dP 'if formula (8) is not satisfied, or formula (8) is not satisfied'_d＝P_d-μ_d(ii) a Otherwise according to P'_cxChecking P_dWhether or not the formulas (3) to (6) are satisfied at the same time;

if not simultaneously satisfying formulae (3) - (6), P'_d＝P_d-μ_d(ii) a Otherwise according to P'_cxChecking P_dWhether formula (2) is satisfied;

if P_dSatisfy formula (2), P'_d＝P_d，P'_jzAnd P'_fhAre all 0; otherwise, the emergency modulation quantity of the direct current power at the moment is P_d,0And returning to increase P according to the step size of the emergency modulation of the DC power_dAnd performing subsequent operations until P 'is obtained'_d。

Obtaining the coordinated control quantity of the accurate load cutting according to the coordinated control sequence of the pumping storage pump cutting, the direct current power emergency modulation, the accurate load cutting and the load cutting comprises the following steps:

let P_fhAnd the initial value of the accurate load cutting amount is 0, and P is increased according to the step length of the accurate load cutting_jzAt this time P_jz＝P_jz,0+μ_jz，P_jz,0To be an initial value of the accurate load shedding amount, mu_jzThe step length of accurate load shedding is obtained;

checking P_jzP 'if formula (9) is not satisfied, or if formula (9) is not satisfied'_jz＝P_jz-μ_jz(ii) a Otherwise according to P'_cxAnd P'_dChecking P_jzWhether or not the formulas (3) to (6) are satisfied at the same time;

if P_jzDo not simultaneously satisfy the formulas (3) - (6), P'_jz＝P_jz-μ_jz(ii) a Otherwise according to P'_cxAnd P'_dChecking P_jzWhether formula (2) is satisfied;

if P_jzSatisfy formula (2), P'_jz＝P_jz，P'_fhIs 0; otherwise, the accurate load shedding amount at the moment is P_jz,0And returning to increase P according to the step length of the accurate load cutting_jzAnd performing subsequent operations until P 'is obtained'_jz。

The method for obtaining the coordinated control quantity of the load shedding according to the coordinated control sequence of the pumping storage load shedding pump, the direct-current power emergency modulation, the accurate load shedding and the load shedding comprises the following steps:

make the initial value of load-cutting quantity be 0, and according to the step length of load-cutting increase P_fhAt this time P_fh＝P_fh,0+μ_fh，P_fh,0To cut the initial value of the load, mu_fhIs the step length of load shedding;

checking P_fhP 'if formula (10) is not satisfied, or formula (10) is not satisfied'_fh＝P_fh-μ_fh(ii) a Otherwise according to P'_cx、P'_dAnd P'_jzChecking P_fhWhether or not the formulas (3) to (6) are satisfied at the same time;

if P_fhDo not simultaneously satisfy the formulas (3) - (6), P'_fh＝P_fh-μ_fh(ii) a Otherwise according to P'_cx、P'_dAnd P'_jzChecking P_fhWhether formula (2) is satisfied;

if P_fhSatisfy formula (2), P'_fh＝P_fh(ii) a Otherwise, let the load shedding amount at this time be P_fh,0Returning to increasing P according to the step size of load shedding_fhAnd performing subsequent operations until P 'is obtained'_fh。

The invention also provides a multi-resource coordination control device of the direct current blocking fault impact alternating current channel, which comprises the following components:

the first determining module is used for determining the static stability limit of the alternating current channel;

the second determining module is used for determining a multi-resource coordination control sequence and coordination control quantity according to the multi-resource coordination control model meeting the constraint conditions; the multi-resource coordination control model comprises an objective function constructed by taking the minimum load shedding amount as a target, and the constraint condition is determined according to the static stability limit of the alternating current channel;

and the coordination control module is used for performing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity.

The first determining module is specifically configured to:

judging whether the following two conditions are met simultaneously:

The second determining module is specifically configured to:

determining an objective function of the formula:

F＝min P_fh (1)

S₀-ΔS(P_cx,P_d,P_jz,P_fh)≤S_lim (2)

P_s,0+ΔP_s(P_cx,P_d,P_jz,P_fh)≤P_s,max (3)

P_c,0+ΔP_c(P_cx,P_d,P_jz,P_fh)≤P_c,max (4)

wherein, P_s,0For saving the initial active power of the elements in the vicinity of the interruption, P_s,maxFor saving elements in the vicinity of the discontinuitiesThermal stability limit of (1), Δ P_s(P_cx,P_d,P_jz,P_fh) Is the active power change of the element in the adjacent region of the provincial section; p_c,0For controlling the initial active power of elements in the near zone of the site, P_c,maxFor controlling the thermal stability limit of the elements in the near-field of the site, Δ P_c(P_cx,P_d,P_jz,P_fh) An active power change amount for an element in a near zone of a control site;

U_s,min≤U_s,0+ΔU_s(P_cx,P_d,P_jz,P_fh)≤U_s,max (5)

U_c,min≤U_c,0+ΔU_c(P_cx,P_d,P_jz,P_fh)≤U_c,max (6)

0≤P_cx≤P_cx,max (7)

wherein, P_cx,maxThe upper limit of the pumping and storage switching pump;

0≤P_d≤P_d,max (8)

wherein, P_d,maxIs the upper limit of the emergency modulation of the DC power, when the emergency modulation of the DC power is speedWhen increasing the modulation, P_d,maxThe upper limit of the direct current power is increased rapidly, and the value is 10 percent P_d,e(ii) a When the emergency modulation of the DC power is the speed drop modulation, P_d,maxThe upper limit of the emergency modulation of the direct current power is 90 percent P_d,e，P_d,eActive power delivered to the dc transmission system;

0≤P_jz≤P_jz,max (9)

wherein, P_jz,maxThe upper limit of the precise load shedding;

0≤P_fh≤P_fh,max (10)

wherein, P_fh,maxThe upper limit of the shear load.

The second determining module is specifically configured to:

let P_fhAnd the initial value of the accurate load cutting amount is 0, and P is increased according to the step length of the accurate load cutting_jzAt this time P_jz＝P_jz,0+μ_jz，P_jz,0Is refinedInitial value of quasi-tangential load, μ_jzThe step length of accurate load shedding is obtained;

The second determining module is specifically configured to:

Compared with the closest prior art, the technical scheme provided by the invention has the following beneficial effects:

the invention provides a multi-resource coordination control method for a direct current blocking fault impact alternating current channel, which comprises the steps of firstly determining the static stability limit of the alternating current channel; then determining a multi-resource coordination control sequence and a coordination control quantity according to the multi-resource coordination control model meeting the constraint conditions; the multi-resource coordination control model comprises an objective function constructed by taking the minimum load shedding amount as a target, and the constraint condition is determined according to the static stability limit of the alternating current channel; finally, realizing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity;

the multi-resource coordination control device of the direct current blocking fault impact alternating current channel comprises a first determining module, a second determining module and a coordination control module, wherein the first determining module is used for determining a static stability limit of the alternating current channel, the second determining module is used for determining a multi-resource coordination control sequence and a coordination control quantity according to a multi-resource coordination control model meeting constraint conditions, the coordination control module is used for performing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity, and finally multi-resource coordination control is achieved;

the technical scheme provided by the invention is considered more comprehensively, integrates the pumping storage switching pump, the direct current power emergency modulation, the accurate load switching and the load switching multi-type control resources, and enriches the safe and stable control means of the power grid;

the technical scheme provided by the invention provides a multi-resource coordination control model considering constraint conditions, the objective function of the multi-resource coordination control model takes load shedding quantity minimization as an optimization objective, the instability problem of the alternating current channel caused by the impact of the direct current blocking fault is solved, other safety and stability problems of the power grid can not be caused, the method comprises the steps that constraint conditions including inequality constraint of a weak alternating current channel in a static stability limit, inequality constraint of elements in a thermal stability limit, inequality constraint of bus voltage in an upper and lower limit range, upper and lower limit constraint of pumping and storage switching pump capacity, upper and lower limit constraint of direct current power emergency modulation capacity, upper and lower limit constraint of accurate load switching capacity and upper and lower limit constraint of load switching capacity are considered, multi-resource control implemented according to a multi-resource coordination control model is adopted, control effectiveness is improved, control cost is reduced, and power grid defense performance is improved;

the technical scheme provided by the invention adopts the heuristic algorithm to obtain the multi-resource coordination control sequence and obtains the multi-resource coordination control quantity on the basis of the multi-resource coordination control sequence, and the multi-resource coordination control quantity obtained by the heuristic algorithm has strong interpretability and better practicability.

Drawings

Fig. 1 is a flowchart of a multi-resource coordination control method for an ac channel impacted by a dc blocking fault in embodiment 1 of the present invention;

fig. 2 is a schematic structural diagram of an extra-high voltage ac/dc interconnected power grid between the target north-annualized area and other regional power grids in the future in embodiment 2 of the present invention;

FIG. 3 is a graph of power fluctuation of the long south line under a DC blocking fault in embodiment 2 of the present invention;

fig. 4 is a schematic diagram of the wind turbine terminal voltages of the near dc region and the sn alliance base station under different modulation amounts of the direct current of the tai tin in embodiment 2 of the present invention;

fig. 5 is a schematic view of a channel flow of interconnection between a tin alliance base and a main network under different modulation amounts of tin tai direct current in embodiment 2 of the present invention;

fig. 6 is a schematic view of a south-of-the-south direct current near zone and provincial power flow simulation under multi-resource coordination control in embodiment 2 of the present invention;

fig. 7 is a schematic diagram illustrating a voltage simulation of a proximate direct current region and a node of a provincial junction in the south of the china under multi-resource coordination control according to embodiment 2 of the present invention;

FIG. 8 is a schematic diagram illustrating a power curve of a long south line under coordinated control and under no measure of multiple resources in embodiment 2 of the present invention;

fig. 9 is a schematic diagram of a multi-resource coordination control strategy for a weak ac channel impacted by a dc blocking fault in embodiment 2 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Example 1

The embodiment 1 of the present invention provides a multi-resource coordination control method for a direct current blocking fault impact alternating current channel, and a specific flow is shown in fig. 1, which specifically includes the following steps:

s101: determining a static stability limit of an alternating current channel;

s102: determining a multi-resource coordination control sequence and a coordination control quantity according to a multi-resource coordination control model meeting constraint conditions; the multi-resource coordination control model comprises an objective function constructed by taking the minimum load shedding amount as a target, and the constraint condition is determined according to the static stability limit of the alternating current channel determined in the S101;

s103: and performing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity determined in the step S102.

In the above S101, the specific process of determining the static stability limit of the ac channel is as follows:

1. setting the static active power of an alternating current channel to be 0, establishing a steady-state power flow model and an electromechanical transient model based on power system simulation analysis software such as PSD-BPA (phase-sensitive detector-BPA), and simulating a direct current blocking fault to obtain a power angle curve of a generator relative to a reference machine and an out-of-step oscillation center of a strong weak alternating current power grid;

2. judging whether the following two conditions are met simultaneously:

The objective function in S102 is as follows:

F＝min P_fh (1)

The constraint conditions comprise inequality constraint of a weak alternating current channel in a static stability limit, inequality constraint of elements (including a line and a transformer) in a thermal stability limit, inequality constraint of bus voltage in an upper and lower limit range, upper and lower limit constraint of pumping and storage switching pump capacity, upper and lower limit constraint of direct current power emergency modulation capacity, upper and lower limit constraint of accurate load shedding capacity and upper and lower limit constraint of load shedding capacity, and the constraint conditions are respectively introduced as follows:

(1) the inequality constraint of the weak ac channel within the static stability limits is as follows:

S₀-ΔS(P_cx,P_d,P_jz,P_fh)≤S_lim (2)

(2) the inequality constraint of the element within the thermal stability limits is as follows:

P_s,0+ΔP_s(P_cx,P_d,P_jz,P_fh)≤P_s,max (3)

P_c,0+ΔP_c(P_cx,P_d,P_jz,P_fh)≤P_c,max (4)

wherein, P_s,0For saving the initial active power of the elements in the vicinity of the interruption, P_s,maxFor saving the thermal stability limit of the element in the vicinity of the interface, Δ P_s(P_cx,P_d,P_jz,P_fh) Is the active power change of the element in the adjacent region of the provincial section; p_c,0For controlling the initial active power of elements in the near zone of the site, P_c,maxFor controlling heat of elements in the near zone of the siteStability limit, Δ P_c(P_cx,P_d,P_jz,P_fh) An active power change amount for an element in a near zone of a control site;

(3) the inequality constraint of the bus voltage in the upper and lower limit ranges is as follows:

U_s,min≤U_s,0+ΔU_s(P_cx,P_d,P_jz,P_fh)≤U_s,max (5)

U_c,min≤U_c,0+ΔU_c(P_cx,P_d,P_jz,P_fh)≤U_c,max (6)

(4) the upper and lower limits of the pumping cut pump amount are constrained as follows:

0≤P_cx≤P_cx,max (7)

wherein, P_cx,maxThe upper limit of the pumping and storage switching pump;

(5) the upper and lower limits of the emergency modulation quantity of the direct current power are constrained as follows:

0≤P_d≤P_d,max (8)

wherein, P_d,maxIs the upper limit of the DC power emergency modulation, when the DC power emergency modulation is the speed-increasing modulation, P_d,maxThe upper limit of the direct current power is increased rapidly, and the value is 10 percent P_d,e(ii) a When the emergency modulation of the DC power is the speed drop modulation, P_d,maxThe upper limit of the emergency modulation of the direct current power is 90 percent P_d,e，P_d,eFor dc transmission system transmissionActive power of (d);

(6) the upper and lower limits of the accurate load shedding amount are constrained as follows:

0≤P_jz≤P_jz,max (9)

wherein, P_jz,maxThe upper limit of the precise load shedding;

(7) the upper and lower limits of the load shedding amount are constrained as follows:

0≤P_fh≤P_fh,max (10)

wherein, P_fh,maxThe upper limit of the shear load.

In step S103, determining the multi-resource coordination control sequence and the coordination control amount according to the multi-resource coordination control model satisfying the constraint condition includes:

1. solving an objective function by adopting a heuristic algorithm to obtain a multi-resource coordination control sequence, wherein the specific process is as follows:

determining a target function which aims at minimizing the load shedding amount, and determining a multi-resource action sequence participating in coordination control by adopting a heuristic algorithm, wherein the pumping storage switching pump and the direct current power emergency modulation do not lose load, and the accurate load shedding and the load shedding lose load, so that the pumping storage switching pump and the direct current power emergency modulation have higher priority than the accurate load shedding and the load shedding action;

because the load is not lost by the pumping and storage switching pump and the direct-current power emergency modulation, but compared with the direct-current power emergency modulation, the pumping and storage switching pump only relates to a local power grid, and the direct-current power emergency modulation relates to a sending-end power grid and a receiving-end power grid, the operation cost is higher, and the action priority of the pumping and storage switching pump is higher than that of the direct-current power emergency modulation; compared with the direct load loss of the load shedding, the load shedding of the precision load shedding also loses the load, but the influence is small, so the priority of the action of the precision load shedding is higher than that of the load shedding.

It is thus possible to obtain: the priority of a pumping storage switching pump, direct current power emergency modulation, accurate load switching and load switching is sequentially changed from high to low; namely, after a fault, the pumping storage switching pump and the direct current power emergency modulation are preferably and sequentially put into control, the accurate load shedding and the load shedding are sequentially considered when the capacity of the control resource is still insufficient and the stability of the power grid cannot be recovered, the control of the resource is carried out according to the sequence until the power grid is stable, the load shedding amount can be reduced, and the optimization target is realized.

2. According to the coordination control sequence of the pumping and storage switching pump, the direct current power emergency modulation, the accurate load cutting and the load cutting, the coordination control quantity of the pumping and storage switching pump, the direct current power emergency modulation, the accurate load cutting and the load cutting is obtained, and the specific process is as follows:

2-1) obtaining the coordination control quantity of the pumping storage cutting pump according to the coordination control sequence of the pumping storage cutting pump, the direct current power emergency modulation, the accurate cutting load and the cutting load:

let P_d、P_jz、P_fhAnd the initial value of the pumping amount is 0, and is increased by P according to the step length of the pumping amount_cxAt this time P_cx＝P_cx,0+μ_cx，P_cx,0To take the initial value of the pumping amount, mu_cxFor the step size of the pump, mu_cxCan take 100 MW;

2-2) obtaining the coordination control quantity of the direct current power emergency modulation according to the coordination control sequence of the pumping storage switching pump, the direct current power emergency modulation, the accurate load switching and the load switching:

let P_jz、P_fhAnd the initial values of the emergency modulation quantity of the direct current power are all0 and increases P according to the step size of the DC power emergency modulation_dAt this time P_d＝P_d,0+μ_d，P_d,0Is an initial value of the DC power emergency modulation quantity, mu_dStep size, mu, for emergency modulation of DC power_dCan take 100 MW;

2-3) obtaining the coordination control quantity of the accurate load cutting according to the coordination control sequence of the pumping storage cutting pump, the direct current power emergency modulation, the accurate load cutting and the load cutting:

let P_fhAnd the initial value of the accurate load cutting amount is 0, and P is increased according to the step length of the accurate load cutting_jzAt this time P_jz＝P_jz,0+μ_jz，P_jz,0To be an initial value of the accurate load shedding amount, mu_jzStep size, mu, for precise load shedding_jzCan take 100 MW;

2-4) obtaining the coordination control quantity of the load shedding according to the coordination control sequence of the pumping storage and switching pump, the direct current power emergency modulation, the accurate load shedding and the load shedding:

make the initial value of load-cutting quantity be 0, and according to the step length of load-cutting increase P_fhAt this time P_fh＝P_fh,0+μ_fh，P_fh,0To cut the initial value of the load, mu_fhFor the step size of load shedding, μ_fhCan take 100 MW;

In conclusion, P 'is finally obtained'_cx、P'_d、P'_jzAnd P'_fh。

Based on the same inventive concept, embodiment 1 of the present invention further provides a multi-resource coordination control apparatus for a dc blocking fault impact ac channel, where the principle of these apparatuses to solve the problem is similar to a multi-resource coordination control method for a dc blocking fault impact ac channel, and the multi-resource coordination control apparatus for a dc blocking fault impact ac channel provided in embodiment 1 of the present invention may include a first determining module, a second determining module, and a coordination control module, and the functions of the three modules are respectively described below:

the second determining module is used for determining a multi-resource coordination control sequence and coordination control quantity according to the multi-resource coordination control model meeting the constraint conditions; the multi-resource coordination control model comprises an objective function constructed by taking the minimum load shedding amount as a target, and the constrained condition is determined according to the static stability limit of the alternating current channel;

the coordination control module is used for performing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity.

The specific process of the first determining module for determining the static stability limit of the ac channel is as follows:

1. setting the static active power of an alternating current channel to be 0, and simulating the direct current blocking fault based on a steady-state power flow model and an electromechanical transient model to obtain a power angle curve of a generator relative to a reference machine and an out-of-step oscillation center of a strong weak alternating current power grid;

2. judging whether the following two conditions are met simultaneously:

The second determining module determines an objective function as follows:

F＝min P_fh (1)

The constraint conditions comprise inequality constraint of a weak alternating current channel in a static stability limit, inequality constraint of an element in a thermal stability limit, inequality constraint of bus voltage in an upper and lower limit range, upper and lower limit constraint of pumping and storage switching pump capacity, upper and lower limit constraint of direct current power emergency modulation capacity, upper and lower limit constraint of accurate load cutting capacity and upper and lower limit constraint of load cutting capacity, and are specifically as follows:

S₀-ΔS(P_cx,P_d,P_jz,P_fh)≤S_lim (2)

P_s,0+ΔP_s(P_cx,P_d,P_jz,P_fh)≤P_s,max (3)

P_c,0+ΔP_c(P_cx,P_d,P_jz,P_fh)≤P_c,max (4)

wherein, P_s,0For saving the initial active power of the elements in the vicinity of the interruption, P_s,maxFor saving the thermal stability limit of the element in the vicinity of the interface, Δ P_s(P_cx,P_d,P_jz,P_fh) Is the active power change of the element in the adjacent region of the provincial section; p_c,0For controlling the initial active power of elements in the near zone of the site, P_c,maxFor controlling the thermal stability limit of the elements in the near-field of the site, Δ P_c(P_cx,P_d,P_jz,P_fh) An active power change amount for an element in a near zone of a control site;

U_s,min≤U_s,0+ΔU_s(P_cx,P_d,P_jz,P_fh)≤U_s,max (5)

U_c,min≤U_c,0+ΔU_c(P_cx,P_d,P_jz,P_fh)≤U_c,max (6)

0≤P_cx≤P_cx,max (7)

wherein, P_cx,maxThe upper limit of the pumping and storage switching pump;

0≤P_d≤P_d,max (8)

wherein, P_d,maxIs the upper limit of the DC power emergency modulation, when the DC power emergency modulation is the speed-increasing modulation, P_d,maxThe upper limit of the direct current power is increased rapidly, and the value is 10 percent P_d,e(ii) a When the emergency modulation of the DC power is the speed drop modulation, P_d,maxThe upper limit of the emergency modulation of the direct current power is 90 percent P_d,e，P_d,eActive power for DC transmission system；

0≤P_jz≤P_jz,max (9)

wherein, P_jz,maxThe upper limit of the precise load shedding;

0≤P_fh≤P_fh,max (10)

wherein, P_fh,maxThe upper limit of the shear load.

The determining, by the second determining module, the multi-resource coordination control sequence and the coordination control amount according to the multi-resource coordination control model satisfying the constraint condition further includes:

1. solving the objective function by adopting a heuristic algorithm to obtain the following multi-resource coordination control sequence:

let P_fhAnd the initial value of the accurate load shedding amount are both 0,and increasing P according to the step length of the accurate load shedding_jzAt this time P_jz＝P_jz,0+μ_jz，P_jz,0To be an initial value of the accurate load shedding amount, mu_jzThe step length of accurate load shedding is obtained;

To sum up, P 'is obtained'_cx、P'_d、P'_jzAnd P'_fh。

Example 2

Taking a certain target mode of the power grid in North China as an example, the specific process of the multi-resource coordination control method for the direct current blocking fault impact alternating current channel is elaborated in detail:

the structural schematic diagram of an extra-high voltage alternating current-direct current interconnected power grid between the target north-China and other regional power grids in the future is shown in fig. 2, the unit in fig. 2 is ten thousand watts, and the power grids in North-China and China are interconnected through an extra-high voltage 'Changzhi-south sun-Jingmen' (long south line for short), and two operation modes exist: the north in the flood season (power transmission to north in china) and the south in the dry season (power transmission to north in china). The power of the extra-high voltage direct current upper temporary green pricking and the extra-high voltage direct current green pricking are respectively 1000 ten thousand kilowatts and 400 ten thousand kilowatts of high-voltage direct current Yidong power; the power of the extra-high voltage direct current tinny gas delivered to the outer wall and the power of the Jinnan are respectively 750 kilo-watts and 800 kilo-kilowatts.

The extra-high voltage direct current and the long south line have two modes of sending out and receiving in, under the direct current blocking fault, the risk that the long south line under the alternating current-direct current same-direction (same sending and same receiving) transmission mode goes beyond the static stability limit and generates transient instability is higher than that under the different-direction transmission mode, the transient instability leads to the splitting of the long south line, the scale of the system is reduced after splitting, the frequency problem is easy to occur, and the operation risk of the system is increased.

Therefore, in embodiment 2 of the present invention, research is performed mainly based on a typical mode of sending 550 ten thousand kilowatts from north to south along the long south line, and the corresponding dc blocking fault is a 1000 ten thousand kilowatts dc blocking fault fed into the Shandong. And (3) adopting PSD-BPA and other power system simulation analysis software to construct a steady-state power flow model and an electromechanical transient model, wherein the direct current model is a quasi-steady-state model based on an ABB actual controller.

Firstly, determining multiple control resources for preventing the instability problem of the strong and weak AC power grid caused by the impact of the control DC blocking fault on the AC channel:

(1) the instability mode of the strong weak alternating current power grid caused by the impact of the direct current blocking fault on the alternating current channel is as follows:

because north China has three incoming direct current near-electric-distance concentrated falling points in Shandong province, namely the upper direct current, the lower direct current and the silver east direct current are the same-sending direct current and the same-receiving direct current of which the sending ends are both positioned in Ningxia in northwest, when the alternating current network frame has serious faults of N-2, single-phase switch failure and the like, the simultaneous continuous phase change failure of multiple direct currents is easily caused, the direct current operation is continuously unstable, and the direct current protection acts and locks the direct currents for the purposes of protecting a direct current equipment body and the like, namely, the possibility of simultaneous locking of the multiple direct currents exists.

Based on 550 ten thousand kilowatts sent by the long south line north, transient power fluctuation and disconnection conditions of the long south line under 400 ten thousand kilowatts of Yinto direct current blocking, 1000 ten thousand kilowatts of upward direct current blocking and upward and Yinto two direct current blocking (1400 ten thousand kilowatts) are simulated, and instability models and severity of impact of the direct current blocking on the weak alternating current channel under three modes are compared and analyzed. The power fluctuation curve of the long south line under the direct current blocking fault is shown in fig. 3, and the disconnection conditions of the long south line under different impact strengths of the direct current blocking are shown in table 1;

TABLE 1

As can be seen from fig. 3, the dc latch-up fault impacts the long south line, and the power angle is relatively instable in north and south china, which causes the disconnection of the long south line, and the power angle of the disconnected north china system can be kept stable, but because the power received by the long south line north and the power received by the dc latch-up are lost, the frequency of the disconnected north china system is continuously reduced, and there is a low frequency problem; as can be seen from Table 1, the acceleration of the separation time indicates that the impact strength is gradually increased, the risk is higher, and the prevention strength needs to be enhanced.

(2) Determining multiple control resources of the North China power grid:

1) load shedding

Load shedding safety control is an important measure for dealing with grid faults. The earlier the action is under normal conditions, the better the control effect is, and the time required by the transmission of a safety control signal, the switching action and the like is considered, and the action is generally set to be 0.2s after the fault; concentrated load shedding is mainly adopted, a substation which can provide necessary amount shedding and has high sensitivity is generally selected by an executive station, and a 110kV line, a 10kV feeder line or a 10kV main transformer switch in the substation is a main shedding object. With the increasing of the capacity of the commissioning direct current, only the measures are taken, and the control cost is overlarge. For direct current fed into a Shandong power grid, load cutting places for cutting load safety control after locking are all located in Shandong province, and the load cutting amount of the Shandong province is 100 ten thousand kilowatts in total.

2) Pump for pumping, storing and cutting

The starting operation of the pumping and storage unit to full load needs 1-2 minutes, the conversion from the pumping state to the power generation only needs 3-4 minutes, and the working condition conversion is rapid. When the pumping storage is operated in a load state, the traditional load switching safety control can be replaced by the switching pump, and the purpose of maintaining the stability of the system is achieved.

The target annual north China pumped storage controllable amount is 427 ten thousand kilowatts, and comprises a Beijing thirteen-tombs pumped storage power station (4 x 20), a Hebei Nanjing Yangtze river gulf pumped storage power station (4 x 25), a Shanxi dragon pond pumped storage power station (4 x 30), a Shandong Taishan pumped storage power station (4 x 25) and a Jibei pumped storage power station (3 x 9).

3) Accurate load shedding

The traditional load shedding safety control technology mainly cuts off a main transformer and a high-voltage load line, has large influence on users, small selectable capacity and difficult realization of large-scale load shedding. Different from the traditional load shedding safety control technology, the accurate load shedding is an innovative technology of power grid operation, has the advantages of multiple points, wide range, strong selectivity, small influence on users and capability of realizing accurate control in millisecond level, can meet the objective requirements of multiple direct current blocking faults on a large number of load shedding through the synergistic effect with a traditional load control system, and is an effective means for guaranteeing the safety of a power grid in a transition period.

In order to deal with the direct current blocking fault, the precise load control is planned to be popularized in the provinces of the extra-high voltage direct current receiving end, and the north China power grid is expected to deploy precise load shedding resources with the total quantity of 150 ten thousand kilowatts in Shandong fed with direct current.

4) DC power modulation

The direct current system is controllable in height, high in adjusting speed and high in power adjusting capacity, and can improve stability and reduce control cost by using direct current modulation and matching with conventional safety control measures. The north China power grid comprises a plurality of loops of sending and receiving concurrent direct currents, and if the received direct current has a locking fault, the rest of the sent direct currents can be subjected to power emergency speed reduction modulation.

(3) Partitioning of out-of-zone resources within a region

With the fault direct current drop point provincial power grid as the boundary, the north China controllable resources can be defined as the resources inside and outside the district. For the upstream direct current lock feeding to Shandong, the resources in the district include the pump and the accurate load cutting in Shandong province; and the rest Shandong provinces pump out, accumulate and cut the pump and the Shanxi and Xitai provinces of the drop point, the south of Shanxi and Xitai Union send out direct current emergency power to quickly reduce to the resources outside the district.

Determining a multi-resource coordination control model meeting constraint conditions according to the multi-control resources and the static stability limit of the alternating current channel:

(1) and constructing an objective function with the minimum load shedding amount as a target, wherein the objective function is as follows:

F＝min P_fh

(2) Determining a constraint condition:

the coordination control measures are used for solving the long south line problem, and simultaneously meet corresponding constraint conditions, namely other safety and stability problems of the North China power grid (the safety problem of a direct current opposite-end power grid can be caused when the direct current is modulated, and the safety problem is not considered temporarily).

the inequality constraint of the weak ac channel within the static stability limits is as follows:

S₀-ΔS(P_cx,P_d,P_jz,P_fh)≤S_lim

wherein，S₀For the dynamic active power peak, S, of the AC channel after a DC blocking fault_limΔ S (P) which is the static stability limit of the AC channel_cx,P_d,P_jz,P_fh) For dynamic active power peak change of AC channel, P_cxFor pumping the pump volume, P_dFor emergency modulation of DC power, P_jzFor precise load shedding, P_fhFor load shedding, cx represents pumping and pump shedding resources, d represents direct current power emergency modulation resources, jz represents accurate load shedding resources, and fh represents load shedding resources;

P_s,0+ΔP_s(P_cx,P_d,P_jz,P_fh)≤P_s,max

P_c,0+ΔP_c(P_cx,P_d,P_jz,P_fh)≤P_c,max

U_s,min≤U_s,0+ΔU_s(P_cx,P_d,P_jz,P_fh)≤U_s,max

U_c,min≤U_c,0+ΔU_c(P_cx,P_d,P_jz,P_fh)≤U_c,max

wherein, U_s,minAnd U_s,maxRespectively for bus voltage in the vicinity of the economized sectionLower and upper limits, U_s,0For the initial voltage of the busbar in the vicinity of the saving section, Δ U_s(P_cx,P_d,P_jz,P_fh) The change quantity of the bus voltage in the adjacent area of the provincial section; u shape_c,minAnd U_c,maxLower and upper limits, U, respectively, of the bus voltage in the vicinity of the control location_c,0For controlling the initial voltage of the busbar in the vicinity of the site, Δ U_c(P_cx,P_d,P_jz,P_fh) For controlling the bus voltage variation in the near zone;

the upper and lower limits of the pumping cut pump amount are constrained as follows:

0≤P_cx≤P_cx,max

wherein, P_cx,maxThe upper limit of the pumping and storage switching pump;

the upper and lower limits of the emergency modulation quantity of the direct current power are constrained as follows:

0≤P_d≤P_d,max

the upper and lower limits of the accurate load shedding amount are constrained as follows:

0≤P_jz≤P_jz,max

wherein, P_jz,maxThe upper limit of the precise load shedding;

0≤P_fh≤P_fh,max

wherein, P_fh,maxThe upper limit of the shear load.

Thirdly, determining a multi-resource coordination control sequence and a coordination control quantity according to the multi-resource coordination control model meeting the constraint conditions:

(1) solving the objective function by adopting a heuristic algorithm to obtain the following multi-resource coordination control sequence:

(2) according to the coordination control sequence of the pumping and storage switching pump, the direct current power emergency modulation, the accurate load cutting and the load cutting, the coordination control quantity of the pumping and storage switching pump, the direct current power emergency modulation, the accurate load cutting and the load cutting is obtained, and the specific process is as follows:

for the pumping and storage cutting pump, 427 ten thousand kilowatts can be organized in the north China target year; the accurate load cutting is organized in Shandong province fed with direct current, and the accurate load cutting amount in a target year is estimated to be 150 ten thousand kilowatts.

2 times of direct current for outward delivery, namely ultra-high voltage stannic acid direct current with 750 ten thousand kilowatts for outward delivery and Jinnan direct current with 800 ten thousand kilowatts, exist in the northern area of the target year, and the problem of locking of the upward direct current fed into the Shandong is solved, two direct currents for outward delivery need to be subjected to power emergency speed reduction modulation, and the direct current speed reduction can be reduced to 10 percent at most (the reduction amplitude is 90 percent); because the direct current overload operation time is usually short, and the clearing time of the power grid accident is indefinite, the direct current body safety is influenced because the direct current power lifting for dealing with the accident causes the direct current body overload for a long time, and the emergency lifting of the direct current power is not considered as a measure for the moment. Therefore, in response to the problem of the last direct current blocking fed into the Shandong, the other two direct current prick green and Yinton fed into the Shandong do not participate in the coordination control.

The resources in the region can balance the power unbalance amount caused by direct current locking in the region in situ, larger power ride-through is avoided, and the influence on the safety of a power grid is smaller, so that the pump switching, accurate load switching and load switching in the region are not subjected to inequality constraint of elements in a thermal stability limit and inequality constraint of bus voltage in an upper limit and a lower limit range. Although the control quantity of the pump switching control resources outside the district is large, the implementation places are dispersed, the safety influence on the external connection section of the local power grid and the pump switching implementation province is limited, and the safety influence on the external connection section is reflected more on the safety influence on the Shandong province. The speed drop modulation amount of the outgoing direct current has large margin, and the places are concentrated, so that the influence on the provincial section is generated, and the safety of a nearby power grid is also greatly influenced.

The method is characterized in that the analysis and the power grid safety out-of-area direct current modulation amount are taken as key points, a pump is switched, 10% and 20% of direct current speed reduction of stannic oxide and Jinnan are respectively set, 427 ten thousands of pumps are switched, the impact influence of the direct current modulation and the pump switching on the direct current near area and the provincial section safety is analyzed, and the reasonable out-of-area direct current modulation amount and the pump switching amount are determined on the basis: a) cutting the pump (totally), reducing the direct current modulation speed by 10% + cutting the load; b) the voltage of the wind turbine terminal of the direct current near area and the tin tai base under different modulation amounts of the direct current is schematically shown in fig. 4, and the power flow of the channel interconnecting the tin tai base and the main network under different modulation amounts of the direct current is schematically shown in fig. 5.

The direct current of the Tutai mainly transmits wind power and fire power of a Sn Union power base, the matched power supply investment in a transition period is small, meanwhile, due to the pressure of energy conservation and emission reduction, the matched power supply is developed and invested in large-scale wind power, the wind power reactive support and fault ride-through capability are insufficient, and the risk of coupling operation with a power grid is increased; the tin alliance power base and the North China main network are connected to a network in a long distance only through tin alliance-victory-corridor extra-high voltage direct current points, the network frame structure is relatively weak, and in order to meet the transmission power of 7500MW of tin Tai direct current, about 3000MW of power is transmitted to the tin alliance base from the North China main network.

After the tin union direct current speed is reduced, the tin union direct current speed and the main network-transmitted current form 'hedging', the tin union direct current near-region current is reduced, the voltage is greatly increased, and the increase range is aggravated by the weak reactive power support of large-scale wind power integration. As can be seen from fig. 4 and 5, the dc speed is reduced by 10% relative to 20%, the dc transmission power is reduced by 750MW, the steady-state current of the sn union-victory-corridor is reduced from 2300MW to 1570MW, the voltage of the sn tai dc converter bus is increased from 1.03p.u. (543.4kV, reference voltage is 525kV) to about 1.07p.u. (562kV), the voltage at the wind turbine end of the near region is increased from 1.056p.u to about 1.09p.u., there is an overvoltage problem (steady-state overvoltage limit value of 550kV), and the wind turbine also has a risk of chain grid disconnection due to insufficient high-voltage fault ride-through performance. The network frame of the near zone of the direct current of shannan is strong, and has no overload and voltage problems, a schematic diagram of power flow simulation of the near zone of the direct current of shannan and the province level under multi-resource coordination control is shown in fig. 6, and a schematic diagram of voltage simulation of the near zone of the direct current of shannan and the province level node under multi-resource coordination control is shown in fig. 7. From fig. 6 and 7, it can be known that the system has no other safety problems, the power flow fluctuation of the provincial section is large, but the system has no out-of-limit problem, and the voltage fluctuation is in a reasonable range.

In conclusion, if a 20% fast power reduction measure is taken for the tinny direct current to solve the problem of the instability limit of the long south line, other safety and stability problems may be caused, and therefore, the maximum fast reduction amplitude of the tinny direct current is recommended to be 10%. Similarly, for convenience of implementation, the speed reduction amplitude of another piece of south-promoted direct current is also set to be 10%; the pump cutting amount of 427 ten thousand kilowatts is not adjusted because the safety and stability problems of the provincial section and the near area of the pump cutting are not caused.

After 427 ten thousand kilowatts, tin tai and two direct currents in the south of the world are implemented, the total speed of the two direct currents is reduced by 155 thousand kilowatts (10% of direct current power), the load is accurately cut by 150 thousand kilowatts, and then a safety control measure for cutting the load by 100 thousand kilowatts is further taken as a multi-resource coordination control measure, a comparison schematic diagram of a long south line power curve under the multi-resource coordination control and the unforeseen measure is shown in fig. 8, and the load loss statistical conditions under the coordination control implemented according to the sequence and the amount of the multi-resource actions are shown in table 2:

TABLE 2

As can be seen from fig. 8 and table 2, after the dc blocking fault occurs, coordination control is sequentially performed according to the heuristically determined multi-resource action sequence and action amount, the long south line is not split, the system is stable, the load shedding loss is gradually reduced while the system safety is effectively improved, 900 ten thousand kilowatts can be reduced to the maximum, the control cost for dealing with the weak ac channel impacted by the dc blocking is reduced, and the optimization target of the coordination control model is achieved.

Fourthly, performing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity:

under the typical mode of a North China power grid target year, the problem that an extra-high voltage long south line is unstable due to the fact that locking faults occur to 1000 ten thousand kilowatt high-voltage direct current fed into a Shandong, is solved, and a multi-resource coordination control strategy capable of effectively reducing control cost and improving control effectiveness is provided. Fig. 9 shows a schematic diagram of a multi-resource coordination control strategy of a weak ac channel impacted by a dc blocking fault:

coordinating control resources includes: pumping storage and switching on a pump, carrying out emergent rapid reduction modulation on direct current power, precisely switching on a load and switching off the load;

the coordination control sequence is as follows:

firstly, performing pumping storage switching pump and outgoing direct current power emergency rapid drop modulation, then accurately switching load, and finally performing load switching safety control;

the coordinated control action amount is as follows:

427 ten thousand kilowatts of the pumping and storage cutting pump, 155 ten thousand kilowatts of the outward direct current speed reduction modulation, 150 ten thousand kilowatts of the accurate cutting load and 100 ten thousand kilowatts of the safety control of the cutting load.

For convenience of description, each part of the above-described apparatus is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware when implementing the present application.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only intended to illustrate the technical solution of the present invention and not to limit the same, and a person of ordinary skill in the art can make modifications or equivalents to the specific embodiments of the present invention with reference to the above embodiments, and such modifications or equivalents without departing from the spirit and scope of the present invention are within the scope of the claims of the present invention as set forth in the claims.

Claims

1. A multi-resource coordination control method for an alternating current channel impacted by a direct current blocking fault is characterized by comprising the following steps:

determining a static stability limit of an alternating current channel;

performing multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity;

judging whether the following two conditions are met simultaneously:

2. The method of claim 1, wherein the objective function is as follows:

F＝min P_fh (1)

3. The method according to claim 2, wherein the constraint conditions include inequality constraints of the weak ac channel within static stability limits, inequality constraints of elements within thermal stability limits, inequality constraints of bus voltage in upper and lower limit ranges, upper and lower limit constraints of pumping and pumping switching pump capacity, upper and lower limit constraints of dc power emergency modulation capacity, upper and lower limit constraints of accurate load shedding capacity, and upper and lower limit constraints of load shedding capacity.

4. The method of claim 3, wherein the weak AC channel is constrained by an inequality within a static stability limit as follows:

S₀-ΔS(P_cx,P_d,P_jz,P_fh)≤S_lim (2)

P_s,0+ΔP_s(P_cx,P_d,P_jz,P_fh)≤P_s,max (3)

P_c,0+ΔP_c(P_cx,P_d,P_jz,P_fh)≤P_c,max (4)

wherein, P_s,0For saving the initial active power of the elements in the vicinity of the interruption, P_s,maxFor saving the thermal stability limit of the element in the vicinity of the interface, Δ P_s(P_cx,P_d,P_jz,P_fh) Is the active power change of the element in the adjacent region of the provincial section; p_c,0For controlling the initial active power of elements in the near zone of the site, P_c,maxFor controlling the thermal stability limit of the elements in the near-field of the site, Δ P_c(P_cx,P_d,P_jz,P_fh) For controlling active power of components in the near zone of a siteA change amount;

U_s,min≤U_s,0+ΔU_s(P_cx,P_d,P_jz,P_fh)≤U_s,max (5)

U_c,min≤U_c,0+ΔU_c(P_cx,P_d,P_jz,P_fh)≤U_c,max (6)

0≤P_cx≤P_cx,max (7)

wherein, P_cx,maxThe upper limit of the pumping and storage switching pump;

0≤P_d≤P_d,max (8)

0≤P_jz≤P_jz,max (9)

wherein, P_jz,maxThe upper limit of the precise load shedding;

0≤P_fh≤P_fh,max (10)

wherein, P_fh,maxThe upper limit of the shear load.

5. The method for coordinated multi-resource control of a dc blocking fault impact ac channel according to claim 4, wherein the determining the coordinated multi-resource control sequence and the coordinated control quantity according to the coordinated multi-resource control model satisfying the constraint condition includes:

6. The method for coordinated control of multiple resources of a direct current blocking fault impact alternating current channel according to claim 5, wherein obtaining the coordinated control quantity of the pumping and switching pump according to the coordinated control sequence of the pumping and switching pump, the direct current power emergency modulation, the accurate load switching and the load switching comprises:

7. The method of claim 6, wherein obtaining the coordinated control amount of the emergency DC power modulation according to the coordinated control sequence of the pumping cut pump, the emergency DC power modulation, the accurate load shedding and the load shedding comprises:

if P_dSatisfy formula (2), P'_d＝P_d，P′_jzAnd P'_fhAre all 0; otherwise, the emergency modulation quantity of the direct current power at the moment is P_d,0And returning to increase P according to the step size of the emergency modulation of the DC power_dAnd performing subsequent operations until P 'is obtained'_d。

8. The method for coordinated control of multiple resources of a direct current blocking fault impact alternating current channel according to claim 7, wherein obtaining the coordinated control quantity of the accurate load shedding according to the coordinated control sequence of the pumping and switching pump, the direct current power emergency modulation, the accurate load shedding and the load shedding comprises:

if P_jzSatisfy formula (2), P'_jz＝P_jz，P′_fhIs 0; otherwise, the accurate load shedding amount at the moment is P_jz,0And returning to increase P according to the step length of the accurate load cutting_jzAnd performing subsequent operations until P 'is obtained'_jz。

9. The method for coordinated control of multiple resources of a direct current blocking fault impact alternating current channel according to claim 8, wherein obtaining the coordinated control quantity of load shedding according to the coordinated control sequence of the pumping and switching pump, the direct current power emergency modulation, the accurate load shedding and the load shedding comprises:

make the initial value of load-cutting quantity be 0, and according to the step length of load-cutting increase P_fhAt this time P_fh＝P_fh,0+μ_fh，P_fh,0For cutting off the initial loadInitial value, μ_fhIs the step length of load shedding;

checking P_fhP 'if formula (10) is not satisfied, or formula (10) is not satisfied'_fh＝P_fh-μ_fh(ii) a Otherwise according to P'_cx、P′_dAnd P'_jzChecking P_fhWhether or not the formulas (3) to (6) are satisfied at the same time;

if P_fhDo not simultaneously satisfy the formulas (3) - (6), P'_fh＝P_fh-μ_fh(ii) a Otherwise according to P'_cx、P′_dAnd P'_jzChecking P_fhWhether formula (2) is satisfied;

10. A multi-resource coordination control device for an alternating current channel impacted by a direct current blocking fault is characterized by comprising:

the coordination control module is used for carrying out multi-resource coordination control according to the multi-resource coordination control sequence and the coordination control quantity;

the first determining module is specifically configured to:

judging whether the following two conditions are met simultaneously:

11. The apparatus according to claim 10, wherein the second determining module is specifically configured to:

determining an objective function of the formula:

F＝min P_fh (1)

12. The apparatus according to claim 11, wherein the constraint conditions include inequality constraints of the weak ac channel within static stability limits, inequality constraints of elements within thermal stability limits, inequality constraints of bus voltage in upper and lower limit ranges, upper and lower limit constraints of pumping and pumping switching pump capacity, upper and lower limit constraints of dc power emergency modulation capacity, upper and lower limit constraints of accurate load shedding capacity, and upper and lower limit constraints of load shedding capacity.

13. The apparatus of claim 12, wherein the weak ac channel is constrained by the inequality within the static stability limit as follows:

S₀-ΔS(P_cx,P_d,P_jz,P_fh)≤S_lim (2)

P_s,0+ΔP_s(P_cx,P_d,P_jz,P_fh)≤P_s,max (3)

P_c,0+ΔP_c(P_cx,P_d,P_jz,P_fh)≤P_c,max (4)

U_s,min≤U_s,0+ΔU_s(P_cx,P_d,P_jz,P_fh)≤U_s,max (5)

U_c,min≤U_c,0+ΔU_c(P_cx,P_d,P_jz,P_fh)≤U_c,max (6)

0≤P_cx≤P_cx,max (7)

wherein, P_cx,maxThe upper limit of the pumping and storage switching pump;

0≤P_d≤P_d,max (8)

0≤P_jz≤P_jz,max (9)

wherein, P_jz,maxThe upper limit of the precise load shedding;

0≤P_fh≤P_fh,max (10)

wherein, P_fh,maxThe upper limit of the shear load.

14. The apparatus according to claim 13, wherein the second determining module is specifically configured to:

15. The apparatus according to claim 14, wherein the second determining module is specifically configured to:

16. The apparatus according to claim 15, wherein the second determining module is specifically configured to:

17. The apparatus according to claim 16, wherein the second determining module is specifically configured to:

18. The apparatus according to claim 17, wherein the second determining module is specifically configured to: