WO2014173131A1

WO2014173131A1 - Large power grid overall situation on-line integrated quantitative evaluation method based on response

Info

Publication number: WO2014173131A1
Application number: PCT/CN2013/088404
Authority: WO
Inventors: 刘道伟; 李柏青; 马世英; 侯俊贤; 孙华东; 王虹富; 董毅峰; 王毅; 张志强
Original assignee: 国家电网公司; 中国电力科学研究院
Priority date: 2013-04-23
Filing date: 2013-12-03
Publication date: 2014-10-30
Also published as: CN103279638B; CN103279638A

Abstract

A large power grid overall situation on-line integrated quantitative evaluation method based on a response is provided. The method comprises: step S1, acquiring power grid topology structural information from an SCADA system and an EMS system and establishing a correspondence between the power grid topology structural information and a WAMS system power grid component; step S2, acquiring trend data of a current operation manner of the power grid from the SCADA system or the EMS system or a WAMS system or acquiring various preconceived trends or time domain data of a transient fault from a DSA system; and step S3, grouping, from the aspect of tracks, response data into a stable operation scenario (or quasi-stable) and a transient operation scenario (or dynamic), static stabilization situation assessment being performed on a power grid in an on-line node-oriented manner, and transient stabilization situation assessment being performed on the power grid in an on-line unit-oriented method. Static and transient comprehensive assessment indicators are constructed based on component-level thermostabilization, an electric parameter acceptable range, and system-level stabilization, the comprehensiveness and reasonability of the overall situation assessment indicators are improved, and the efficiency of overall situation integrated assessment is improved by using the method out of carrying out tasks concurrently.

Description

An Online Integrated Quantitative Evaluation Method for the Whole Situation of Large Power Grid Based on Response

Technical field

The invention relates to the field of online safety monitoring and early warning of large power grids, and particularly relates to a method for quantitatively evaluating and integrating the full-scale integrated line of large power grids based on response.

Background technique

Ensuring the safety and economic operation of large power grids is a goal that power workers have been pursuing for many years. With the continuous expansion of the interconnection of power grids, the deepening of the reform of the market-oriented power system, and the continuous access of UHV transmission and renewable energy generation, the uncertainty of grid operation has increased, making the grid operating environment and dynamic behavior more Complex, it is more difficult to analyze and control it stably. In the event of an accident in the modern large power grid, if it is not handled in time, the consequences will be very serious. Since 2000, there have been many blackouts in the world. Among them, the " 8.14" blackout in the US and Canada was the biggest blackout in history. The economic loss during the blackout period was as high as 30 billion US dollars. Frequent power outages occurred. The grid security and stability analysis and control, real-time monitoring of grid operation status put forward more urgent requirements.

At present, there are four main problems in the field of online safety assessment and early warning of large power grids: 1 The grid online safety assessment mainly adopts the traditional network modeling and simulation form, although the grid safety assessment based on modeling and simulation is the grid planning and operation. Indispensable important tools, but this method is restricted by factors such as grid model, parameters and numerical calculations. It is difficult to adapt to the real-time monitoring requirements of the grid in terms of application scale, speed and matching with real grid conditions. New ideas and faster solutions; 2 blackouts are often caused by unforeseen cascading failures or random disturbances. Existing "offline pre-decision, online matching" grid security control mode based on expected accident set, cannot Matching the real operating conditions of the grid, and affected by the model and parameters, the resulting scheme is sometimes too conservative (or optimistic), especially the combination of fault set explosions severely limits the number of possible conditions. In the real-time monitoring and prevention of large blackouts in large power grids, it may appear to be incapable; 3 the existing grid online safety assessment system has strong independence when it is specific to specific problems, and often stabilizes the grid power angle and synchronizes stability. Processed, or specifically divided into static and transient problems. However, in fact, grid stability is a unified nonlinear power system stability problem. From the perspective of grid response, power angle and voltage are only an external manifestation, and there is a kind of "moving" between static and transient problems. There is a dialectical thought in which there is silence in the static. Therefore, many existing assessment methods and indicators have great overlap. In the real-time operating environment, there is a need for an evaluation index system that is more effective and can truly reflect the grid operation situation. One of the main reasons for the 4 power outages is the grid that is put into operation. The online monitoring system did not give an intuitive and effective quantitative assessment of the grid operation situation during the slow deterioration of the grid state, nor did it give the corresponding control measures according to the changes in the real operating conditions of the grid, and missed the best opportunity to turn the tide. Therefore, the grid needs to establish a new online safety assessment method system to achieve highly automated and intelligent online safety assessment and early warning of large power grids.

With the development of computer, communication and network technologies, WAMS (Wide Area Measurement System) has been widely used in power grid dispatching automation. It is an online quantitative evaluation and real-time adaptive control research belt for WAMS-based power grid operation. A new opportunity has come. Faced with the above opportunities and challenges, the Smart Grid, which combines advanced measurement sensing technology, control technology, communication technology, computer technology and other cutting-edge technologies, has become the only way for the development of the modern power industry. One of the important functions of the smart grid is to improve the visualization and early warning capabilities of the grid, and ultimately achieve intelligent closed-loop control to make the grid operation safer, more reliable and more economical. Intelligent scheduling is the core content of smart grid construction. Intelligent dispatching technology support system should have the function of “distributing the thinking mode of the dispatcher, using the visual interface as the functional module and interactive computing as the core of the system”.

Smart grid is a grand system engineering to realize online security assessment and early warning of large power grid. It combines the current mature WAMS system and SCADA (Supervisory Control And Data Acquisition) \EMS

(Energy Management System, Energy Management System) and DSA (Dynamic Security Assessment) system for predicting fault set simulation. For different grid operation scenarios, it is necessary to thoroughly study the full-scale quantitative assessment method of large grid based on response information. The data fusion processing mechanism establishes an online security assessment system based on the combination of the current state and the expected state of the large grid based on the multi-response information source.

Summary of the invention

The invention relates to an online integrated quantitative evaluation method for a full-scale potential of a large power grid based on response, comprising:

Step S1, obtaining grid topology information from the SCADA system and the EMS system, and establishing a power with the WAMS system Correspondence of network elements;

Step S2: Obtain current power flow data of the power system from the SCADA system, the EMS system, or the WAMS system, or obtain various expected power flow or transient fault time domain data from the DSA system;

Step S3: Perform static static situation assessment on the grid in an online node-oriented manner, and perform transient stability situation assessment on the grid in a line-oriented pairwise manner;

Among them, the static stability situation assessment of the power grid includes: generator stability margin index, line stability margin index, node stability margin index, generator thermal stability pass rate, line thermal stability pass rate, node voltage pass rate, Load node power factor pass rate, static steady state comprehensive index and node reactive power compensation level indicator;

The contents of the transient stability situation assessment of the power grid include: transient stability margin index, transient stability prediction index, node voltage retention rate, node stability margin index, line thermal stability pass rate and transient stability situation comprehensive index .

In the first preferred embodiment provided by the present invention, various grid static response data include predicted state offline power flow, N-l, N-2 power flow convergence calculation result, SCADA\EMS system state estimation result, and PMU measurement information;

The response data of various grid transient transition processes include various expected transient fault set time domain simulation results, and WAMS real-time measured grid disturbance process information;

For the PMU measurement information, the rationality prediction or filtering process is performed according to the change of the PMU measurement data at the previous moment or the surrounding PMU;

For N-l and N-2 expected faults, they are allocated according to the number of parallel machines.

In the second preferred embodiment provided by the present invention, when the static stable situation assessment and the transient stability situation assessment are performed on the power grid in step S3, all nodes of the power grid are allocated according to the number of parallel machines;

According to the power flow running section information combined with the power grid topology structure, the equivalent transmission power of each node is obtained according to the active flow direction. The tracking parameter identification method based on local measurement is used to identify the equivalent transmission model parameters of the current state of each node of the power grid. The equivalent transmission model parameters include the equivalent power supply potential, the equivalent branch impedance mode, and the impedance angle. The node-equivalent transmission model inverse mapping based on the current operating state of the grid is realized.

In a third preferred embodiment of the present invention, the method for obtaining the generator stability margin index, the line stability margin indicator, and the node stability margin indicator of the power grid in the step S3 is:

According to the idea of maximum transmission power, the static stability margin index corresponding to the current operation mode of the generator branch, the tie line branch or the node is obtained for the generator branch, the tie line branch and the node equivalent transmission model respectively. , i is calculated as: =

Where ZL represents the equivalent load impedance of the generator branch, tie line or node, and is obtained from the terminal voltage and power. In a fourth preferred embodiment of the present invention, the method for obtaining the thermal stability rate of the generator and the thermal stability rate of the connection line of the power grid in the step S3 includes:

According to the thermal stability operation constraints of each generator and the tie line itself, the statistical thermal stability rate of the generator ^^ and the line thermal stability pass rate of £ _PR are: G _PR = ., L _PR = if ,

N ^L N

Among them, G _N , respectively the total number of generators of the grid, the total number of tie lines, G _QN , ^ respectively are the number of generators and tie lines that meet the thermal stability constraints of their respective operations;

The method for obtaining the node voltage pass rate and the load node power factor pass rate of the power grid in the step S3 includes: the node voltage and the load node power factor qualified range upper and lower limits given according to the normal operation mode of the power grid, and the statistical power grid node voltage is qualified. Rate, load node power factor pass rate ^ ^

丄 N ^FN;

Among them, the total number of nodes of the power grid and the number of load nodes, respectively, V _QN , the number of nodes satisfying the voltage range and the number of load nodes satisfying the power factor range. The method for obtaining the static stability rate of the power grid includes:

Set a certain warning threshold c, and count the number of all tie line branches and node equivalent branches of the grid greater than c. The nodes include generator nodes, intermediate contact nodes and load nodes, respectively calculate the line static stability rate _R = ^, node static stability rate N _SR = ^ _;

N

L _N and N _N are respectively the total number of contact lines and the number of nodes in the system, and L _CN and N _CN are respectively the number of contact lines and the number of nodes greater than &c.

In the fifth preferred embodiment provided by the present invention, the method for obtaining the overall static stability situation comprehensive index of the power grid in the step S3 includes:

The overall static stability situation of the grid is a comprehensive indicator = a H _QR + 3⁄4 _Λ + Α;

Where β is the weight coefficient of the grid according to thermal stability constraints, operating electrical quantity constraints and static stability constraints, and flexible configuration according to experience or analysis, A, meets:

^^ is the overall thermal stability rate of the grid, ^^ calculation formula is: H _{QR =} ^^ Λ is the overall operating electrical quantity pass rate of the grid, _Λ calculation formula is: R _QR —

N _N + P _R

Λ is the overall static stability rate of the grid, _Λ calculation formula is: ^S s.

In the sixth preferred embodiment provided by the present invention, the method of virtual reactive power change is used in the step S3 to determine the reactive power required to minimize the active loss of the equivalent power transmission model, and the current operating mode of each node is obtained. The method of compensation level indicator is:

Combining the equivalent transmission model of each node and its equivalent transmission active power A, find the circulation under the node equivalent model

The corresponding reactive power value of A corresponding to A is the minimum value, and then the equivalent power transmission reactive power of the node and the obtained node is compared, and the current running party compensation deficiency indicator a of the respective nodes is obtained as:

Among them, a>o indicates that the reactive power is not compensated, a=o indicates that the reactive power is optimal, and a<o indicates that the reactive power is over-compensated.

In the seventh preferred embodiment provided by the present invention, in the step S3, the time domain data of the grid transient process trajectory is obtained from the WAMS system or various expected transient fault sets, and the method envelope of the severely disturbed crew pair is directly used. The transient behavior of the power grid is obtained, and the transient stability margin indicator of the power grid is obtained, which includes steps S101 to S103:

Step S101, according to the inertia time constant M of each generator and its angular velocity ", power angle, machine side bus voltage phase angle

S and the electromagnetic active power before and after the change of the situation, the rapid identification of the most advanced X and the most delayed X generators, constitute the most severely affected unit set Ω;

The number X can be artificially set according to needs, and the range of X is 5 ≤ x ≤ 10;

Step S102, calculating a generator set and a generator for any one of the lead and lag unit pairs in the set Ω -

The transient stability margin index between groups j T _SIij = ^―^;

. ')■

Wherein, the difference between the power angles between the genset and the genset ', represents the mechanical power function between the genset i and the genset j and the intersection of the electromagnetic active power ^ ^ is virtual stable Flat Balance operating point;

Step S103, sequentially calculating the transient stability margin indicator ⁷ ^ · between any lead and lag generators and the generator set ' in the set Ω, and using the minimum unit pair ⁷ ^ as the transient of the current time domain data Stability Margin Indicator & _SI , ie 5TSI = min r _s nj, j ^ Ω|.

In an eighth preferred embodiment provided by the present invention, the method for calculating includes the step S1021 - step S1023: Step S1021, the equivalent single-machine rotor inertia time constant between the genset and the genset ' is MM.

Μ, .+Μ calculates the mechanical power function between the generator set and the generator set '

M,

^Meq ~ M _{! +} M,. ^M M _{! +} M,. ^Mj .

Respectively, and wherein the generator inertia time constant i and j of the _generator, Ρ Μί and P _Mj are generators and the generators 'power injection machine, the mechanical power of the generator set of injection = Μ ^ω' ^' ~ ^ω ' ₊ Ρ _Ε ;

At step S1022, calculating electromagnetic active power between the genset and the genset '

M,

Μ,.+Μ Μ,.+Μ

Where P _FM = A ² + Β ² , ^A = Dcos(Sj - θ _{ ) + Ecos(S _! - θ), B = Dsin(Sj - θι) - EsiniSi - θ,.)

, „ M EXJ, M, EU

C = tan , B / A), D = ¹ '' , E= ' ^{1 1} , u;

' M _; + Mj X _t M _t + Mj X〗 ' ^U J, ■, ^θ ^ , respectively represent the generator bus voltage amplitude, phase angle and equivalent internal reactance of the generator set and generator set';

In step S1023, 5 _seq = a sin(^) - C is calculated.

The present invention provides a ninth preferred embodiment ^ ^M: For any leading and lagging of the unit within the set Ω, the unit according to the calculated power P _Meq equivalent mechanical and electromagnetic active power P _Eeq change trajectory by curve fitting The technology constructs the transient stability prediction index from the energy point of view, and specifically includes step S201 - step S203:

Step S201, assuming that the equivalent mechanical power of the genset is unchanged during the transient process, the genset is fitted with the following sinusoidal function for the equivalent electromagnetic active power 4 trajectory: ^ = sin(+ 3⁄4;

Where x. , _Xl , is the fitting sine function coefficient to be obtained, indicating the equivalent _{β ϊ of the} generator set _;

Step S202, calculating a transient stability prediction index T _SEIy between the generator set i and the generator set j;

Step S203, sequentially calculating 3⁄4^ of any lead and lag unit pairs in the set Ω, and using the minimum unit pair as the transient stability prediction index STM of the current time domain data, S = min{r _s£/ , , i eQ} -,

The calculating the transient stability estimation index between the genset and the generator set ' in the step S202 includes the step S2021 - the step S2023:

Step S2021, determining an unstable equilibrium point _a after the fault removal according to the ^^ variation trajectory fitting function, where the unstable equilibrium point is the equivalent mechanical power of the generator set and the electromagnetic active power ^^ change rail The intersection of the line, _{a is} calculated as: 3⁄4 _a =^-arctan ^{Meq 3⁄4} -χ _ι;

Step S2022, the transient kinetic energy of the pair of units at the time of the fault removal is:

S ⁱⁿ ( δ _ν

. .

The critical potential energy (deceleration area) absorbed by the system after fault removal is: ^V TB = \ζ [ ^χ ο P _Meq ~]i δ.. where, and. The unit power angle difference between the fault occurrence time and the fault removal time is indicated respectively.

Step S2023, calculating the transient stability prediction index between the generator set and the generator set', wherein the ^/index transient stability meaning is: 3⁄4^>0 transient stability, 3⁄4^ =0 threshold State stable, T _{smj <} Q, transient instability.

In the tenth preferred embodiment provided by the present invention, the method for obtaining the grid node voltage retention rate in the step S3 includes:

The range of node voltage holding capacity in a given transient process: the lower limit and duration of the voltage drop, the number of nodes V of all nodes in the grid that meet the acceptable range of voltage levels in the transient process, and the node voltage in the transient process is calculated. Pass rate of retention ability ^ =3⁄4

W N

The method for obtaining the thermal stability rate of the line in the power grid in the step S3 includes: determining the static stability margin index and the line thermal stability of the node during the transient process: the node static stability margin limit & _c , the line heat The stability limit ^ « and the duration r _c , the number of nodes that the statistical grid meets the static and sustainable range ^, the number of lines satisfying the thermal stability and sustainable range 1⁄2w, calculate the static stability of the node and the thermal stability of the line during the transient process The pass rate s _ra , S _{RA is} calculated as: S _TR = ^{S + LQN} .

In an eleventh preferred embodiment provided by the present invention, the overall transient stability situation comprehensive index of the power grid is obtained in the step S3, S _TI = OC ₂ S _TSEI + ₂ V _TR + Zl^TR;

Among them, " ₂ , A, respectively, the weight coefficient of the grid according to thermal stability constraints, operating electrical quantity constraints and static stability constraints, flexible configuration according to experience or analysis, " ₂ , A, meet:

The invention provides a response-based large-scale grid full-scale integrated online quantitative evaluation method, and the beneficial effects include:

1. The invention provides a method for online quantitative integration assessment of the full-state potential of a large power grid based on the response, which can realize the static and transient states of the large power grid for real-time measurement of the current state of the power grid or various simulation data under the expected state. The overall situation of typical operational scenarios is online and quantitatively evaluated. That is to say, the situation assessment under the current state of the power grid is realized, and the existing DSA expected simulation advantage is fully realized to realize the situation assessment of the predicted state, which is beneficial to the dispatching operation personnel to timely understand the current operating situation of the power grid and the potential system risk of the power grid. Similarly, the method can be indirectly applied to various offline prediction methods or post-stage intelligent evaluation of fault set time domain simulation data, which greatly reduces the workload of planners or mode developers. The core methods used in the present invention are based on grid response data, and have strong independence, and the full situation assessment method and algorithm are direct and simple, and can quickly identify weak nodes or weak areas in any operation mode of the power grid for operation or planning personnel reference. , prevent problems before they occur, reduce or avoid voltage stability accidents, suitable for online engineering applications. The invention can gradually transform the previous "modeling simulation" prevention and control mode into the "track mining" response control mode, which is an extension of the traditional power grid prevention and control ideas and methods, and can effectively improve the online intelligent assessment and early warning level of the large power grid.

2. Obtain the topology relationship of the power grid from the EMS system, which is beneficial to the quantitative evaluation and statistical analysis of the grid full-scale potential for various response data.

3. From the perspective of response, the grid components and voltage levels are directly and statistically analyzed directly from the qualified range. And In the traditional quantitative evaluation of power angle stability and voltage stability situation, static stability focuses on grid transmission capacity, transient stability focuses on energy conservation, and a unified quantitative assessment of the overall situation of large grid based on response is established.

4. The static trend form of the power flow section for any real-time measurement of the power grid or various expected fault forms is used. When the stability of the specific node or the fault set is analyzed, the task parallel method is used to improve the overall evaluation efficiency.

5. Calculate the actual flow (or transfer) power of the node according to the current power flow distribution and topological relationship. Based on this, the node is equivalent to a simplified "single power supply and single load" simplified transmission model, and adopts local The measurement information is online to identify its equivalent transmission parameters, and the equivalent virtual model mapping of all nodes in the grid is realized, which lays a foundation for the next static stability situation assessment.

6. The impedance model is used to evaluate the static steady state potential, and the impedance mode method is applied to the generator branch, transmission line and node equivalent transmission model. The impedance mode method is suitable for fast online calculation and can effectively identify weak units, critical lines and weak nodes in the current operating mode.

7. From the perspective of the qualified range of generator and line thermal stability operation, the thermal stability rate under the current operation mode of the power grid can be counted, and the overload components can be screened quickly and effectively, which is also in line with the habit of visual evaluation of conventional power flow mode.

8. From the point of view of node voltage level and load node power factor, the electrical quantity qualification rate under the current operation mode of the power grid can be statistically evaluated, and the current operating mode voltage and power factor qualification level can be quickly and effectively evaluated, which is also in line with the conventional power flow mode power quality assessment requirements.

9. For the node equivalent power transmission model and line, the impedance model is used to achieve static stability rate statistics.

10. Fully combined with the statistical results, the comprehensive static and stable situation assessment from the component level thermal stability, the running quantity qualified range to the system static stability is realized, and the three weights can be flexibly selected according to the actual operating state and the evaluation focus.

11. By using the constructed node equivalent transmission model and its parameters, the virtual reactive power required to minimize the active loss when the node is currently active can be obtained, and then the reactive power compensation level evaluation of all nodes in the grid under the current operating mode can be realized.

12. When estimating the transient stability margin and transient stability for the transient time domain process information, the dynamic behavior envelope of the most severely disturbed crew pair is directly used to reflect the overall dynamic behavior of the grid, without the need for group equivalence, etc. Processing, the physical meaning is clear and intuitive, and the evaluation results are accurate.

13. In order to reduce the mistakes of the most severely disturbed unit, select the most severe unit set Ω by using various angles, and then select the most serious unit pair from the set Ω to reduce the selection error caused by the weakest unit. Misjudgment of the actual situation of the power grid.

14. For the lead and lag unit pairs in any set Ω, according to the electrical quantity information of each unit, the unit's transient stability margin index is obtained through simple algebraic calculation, and the minimum unit pair in the set Ω is taken as this time. The transient stability margin indicator STM of the time domain data is used to quantitatively evaluate the transient stability margin of the current transient trajectory.

15. Using the trigonometric function to fit the unit to the equivalent power angle function curve is a good reflection of the transient over-trajectory characteristics of the power grid. With this fitting curve, the energy-type transient stability prediction index 7 _£ can be conveniently calculated. It is clear and intuitive, and uses the minimum unit pair in the set Ω as the transient stability prediction index STM of the current time domain data, and then realizes the transient stability quantitative estimation of the current transient trajectory.

16. Using the transient voltage stability habit judgment method, the voltage drop tolerance and duration are used to measure the node voltage holding capacity and the pass rate in a given transient process.

17, using the same method "LIMIT + Duration", combined with static methods of the stable, and stability is obtained on Static thermal stability of the yield of the line _Λ transient process, facilitate the assessment of a given transitory transient The static stability margin and line load level of the nodes in the middle.

18. Fully combined with the statistical results, the comprehensive transient stability situation assessment indicators from the energy system energy conservation, transient voltage retention capability, node static stability and line thermal stability are realized, and the weights are flexibly selected according to the actual dynamic trajectory and the evaluation focus. Calculate the corresponding faults and achieve their severity ranking, improve the on-line analysis efficiency of the expected fault set, effectively quantify the stable situation of multiple transient faults and facilitate the screening of severe transient faults.

19. Using the task parallel method to analyze the transient stability situation of a large number of expected faults in transient faults. DRAWINGS FIG. 1 is a flow chart of an online integrated quantitative evaluation of a full-scale potential based on a response according to the present invention;

Figure 2 is a diagram showing the elements of the comprehensive indicator system provided by the present invention;

FIG. 3 is a schematic diagram of a local node of a power grid provided by the present invention;

FIG. 4 is a schematic diagram of a node equivalent power transmission model provided by the present invention;

FIG. 5 is a schematic diagram of a maximum transmission power boundary impedance mode provided by the present invention;

FIG. 6 is a schematic diagram of a node reactive power compensation level evaluation provided by the present invention;

FIG. 7 is a schematic diagram of a pair of power grid units provided by the present invention;

FIG. 8 is a schematic diagram showing the fitting of the equivalent power angle curve of the unit provided by the present invention;

FIG. 9 is a schematic diagram of an energy type transient stability prediction index provided by the present invention;

FIG. 10 is a flow chart of the online integrated quantitative evaluation of the full-state potential of the large-scale power grid based on the response provided by the present invention. detailed description

The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

The invention provides an online integrated quantitative evaluation method for a full-scale potential of a large power grid based on a response. As shown in FIG. 1 , the present invention provides a global flow-based quantitative evaluation data flow diagram of a full-state potential based on a response. As can be seen from Figure 1, the evaluation method includes:

Step Sl: Obtain the topology information of the power grid from the SCADA system and the EMS system, and establish a correspondence relationship with the components of the WAMS system.

Step S2: Obtain current power flow data of the power system from the SCADA system, the EMS system, or the WAMS system, or obtain various expected power flow or transient fault time domain data from the DSA system.

Step S3: Perform static static situation assessment on the grid in an online node-oriented manner, and perform transient stability posture assessment on the grid in a line-oriented pairwise manner.

In the construction of the comprehensive evaluation index system, the factors of grid component-level thermal stability, operational electrical quantity qualification and system-level stability are comprehensively considered. Figure 2 shows the element of the comprehensive index system provided by the present invention.

Among them, the static stability situation assessment of the power grid includes: generator stability margin index, line stability margin index, node stability margin index, generator thermal stability pass rate, line thermal stability pass rate, node voltage pass rate, Load node power factor pass rate, static steady state comprehensive index and node reactive power compensation level indicator.

The static response data of various power grids include predictive state offline power flow, Nl, N-2 power flow convergence calculation result, SCADA\EMS system state estimation result, PMU measurement information; various power grid transient transition process response data including various expected temporary State-of-the-art fault set time domain simulation results, WAMS real-time measurement of grid disturbance process information; PMU measurement information based on its previous time or surrounding PMU measurement data changes for rationality prediction or filtering; For Nl, N-2 anticipation Fault, assigned according to the number of parallel machines.

In step S3, when the static stability situation assessment and the transient stability situation assessment are performed on the power grid, all the nodes of the power grid are allocated according to the number of parallel machines, as shown in FIG. 3 is a schematic diagram of the local node of the power grid provided by the present invention, and the node may be coupled with the generator. , load, capacitor, circuit and other components are connected.

According to the power flow running section information combined with the power grid topology structure, the equivalent power transmission power of each node is obtained according to the active flow direction.

P _E + jQ _E , as shown in Figure 4 is a schematic diagram of the node equivalent transmission model. The tracking parameter identification method based on local measurement is used to identify the equivalent transmission model parameters of the current state of each node of the grid, including the equivalent power supply potential E _£ , the equivalent branch impedance mode, and the impedance angle. The node of the operational state is inversely mapped by the equivalent transmission model.

In the method for obtaining the generator stability margin index, the line stability margin index and the node stability margin index of the power grid in step S3, the impedance mode index of the maximum power transmission idea as shown in FIG. 5 is used as the static stability margin index. , including: According to the idea of maximum transmission power, respectively, for the generator branch, the tie line branch and the node equivalent transmission model The static stability margin index corresponding to the current running mode of the generator branch, the tie line branch or the node is calculated as:

ZL can represent the equivalent load impedance of the generator branch, contact line or node, respectively, and can be obtained according to the terminal voltage and power. i Measure the size of each generator branch, transmission line load and node static stability margin, and can be used to locate weak units, critical lines and weak nodes.

Specifically, the static stability margin index of all nodes is averaged, and the average static stability margin index of the current operating mode can be obtained. The calculation formula is:

N

c - ≡l

The method for obtaining the thermal stability rate of the generator of the power grid and the thermal stability rate of the tie line in step S3 includes:

According to the thermal stability operation constraints of each generator and tie line, the thermal stability rate of the generator is calculated ^^ and the line heat

G '.QN

The stable pass rate of £ _PR is:

Among them, G _N , respectively the total number of generators of the grid, the total number of tie lines, G _QN , respectively, the number of generators and tie lines that meet the respective thermal stability constraints.

The method for obtaining the node voltage pass rate and the load node power factor pass rate of the power grid in step S3 includes: determining the node voltage and the load node power factor qualified range upper and lower limits according to the normal operation mode of the power grid, and calculating the grid node voltage pass rate, load Node power factor pass _rateΛ

Among them, the total number of nodes and the number of load nodes are respectively V _QN and P _e are the number of nodes satisfying the voltage range and the number of load nodes satisfying the power factor range.

The method for obtaining the static stability rate of the power grid includes:

C a set alarm thresholds, statistical branch power lines and contacts all nodes (node generator, the intermediate connecting nodes, node load) is greater than the equivalent number of branch c, the static stability are calculated line passing rate _R = ^ , node static stability rate NSR

Where L _N and N _N are the total number of contact lines and the number of nodes, respectively, and L _CN and N _CN are respectively the number of tie lines and the number of nodes greater than c.

The method for obtaining the overall static stability situation comprehensive index of the power grid in step S3 includes: the overall static stability situation comprehensive index of the power grid = ^a i ^H QR + Pl ^R _QR + Xl^SR.

Among them, β _γ , respectively, is the weight coefficient of the grid according to thermal stability constraints, operating electrical quantity constraints and static stability constraints, which can be flexibly configured according to experience or analysis needs. A, A, enough to:

^^ is the overall thermal stability rate of the grid, ^^ calculation formula is: H _QR

^G N ^{+ L} N °

_Ώ ^V QN ^ ^R QFN

Λ is the electrical capacity pass rate of the overall operation of the grid, _{Λ the} formula is: Q ^R ~ N + P _Λ is the overall static stability rate of the grid, _{Λ is} calculated as: s _SR = ^{CN CN}

&i comprehensively measures the static steady state level of the power grid under current current conditions, which can effectively quantify the static stability situation of multiple power flow modes.

In step S3, the virtual reactive power change method is used to obtain the reactive power required to minimize the active power loss of the equivalent power transmission model. The schematic diagram of the node reactive power compensation level evaluation is shown in Figure 6, and the current operating mode of each node is obtained. The methods of compensation level indicators include:

Combining the equivalent transmission model of each node and its equivalent transmission active power A, the reactive power value required for the minimum active loss corresponding to the flow A under the node equivalent model can be obtained. Then the equivalent transmission and reactive power are compared with the obtained node. The power β _£ can be used to obtain the reactive power deficiency indicator a for each node in the current operating mode: where a>o indicates reactive power, and a=o indicates that reactive power is optimal, and a<o indicates reactive power. Overkill.

In step S3, the time domain data of the grid transient process trajectory is obtained from the WAMS system or various expected transient fault sets, and the transient behavior analysis of the envelope network is directly adopted by the method of the severely disturbed crew pair, as shown in FIG. The schematic diagram obtains a transient stability margin indicator of the power grid, including steps S101-S103:

Step S101, according to the inertia time constant M of each generator and its angular velocity, the power angle, the phase voltage S of the bus voltage of the machine end, and the change of the electromagnetic power of the machine end 3⁄4 _E , quickly identify the most advanced X station. And the most delayed X-stage generator, which constitutes the most severely affected unit set.

The number X can be artificially set according to needs, and the range of X is 5 ≤ x ≤ 10.

Step S102: Calculate the transient stability margin indicator between the generator set and the generator set for any of the lead and lag unit pairs in the set Ω. ^ =^^.

ϋ

Where, the difference between the power angle and the sum between the generator set and the generator set ',

S _seq is the virtual stable equilibrium operating point of the intersection between the mechanical power function ^^ and the electromagnetic active power P _Eeq between the genset i and the genset j. The method of calculating 5 _seq includes steps S1021 - S1023:

MM. Step S1021, the equivalent single-machine rotor inertia time constant between the generator set and the generator set ' is ' Calculating the mechanical power function between the generator set i and the generator set j ^^ = ^f -^ Γ ^ΡΜ]

Wherein, and the inertia time constants of the generator set ₂ 'and the generator set respectively, and the mechanical injection power of the generator set and the generator set respectively, the mechanical injection power of the generator set = M

At

Step S1022, calculating electromagnetic active power between the genset and the generator set j

2 _{+ B} 2 , A = D cos(3⁄4. -Θ^ + Ε cos( . , B = D sin( -Θ^-Ε sin( . - θ )

C = ^Ε χ' ^{Ε =} _Μ ^Μ _+Μ ^Ε χ ' and respectively indicate generator set and generator set'

The phase voltage of the terminal bus voltage f,. Uj . θ _Xi , respectively represents the amplitude, phase angle and equivalent internal reactance of the generator bus voltage of the generator set and generator set _/.

Step S1023, calculating ^^)^.

^ EM Step S103, sequentially calculating the transient stability margin index between any lead and lag generator sets and the generator set ' in the set Ω with the minimum unit pair?^ as the transient stability margin index of the current time domain data. & _SI , ie STsi = min{r _s/ , , ₀ The positioning of the weak unit can be achieved by the S _{TSI of the} smallest unit pair.

The method for obtaining the transient stability prediction index of the power grid in step S3 includes: using any calculated lead and lag unit pairs in the set Ω, according to the calculated genset pair equivalent mechanical power _Ϋ and electromagnetic active power change trajectory, utilizing The curve fitting technique constructs the transient stability prediction index from the energy point of view. As shown in Fig. 8, the unit fits the equivalent power angle curve. The method for obtaining the transient stability estimation index of the power grid specifically includes the steps S201 to S203:

In step S201, the equivalent mechanical power of the genset can be assumed to be constant during the transient process, and the equivalent electromagnetic active power of the genset can be fitted by the following sine function: y = sin( +3⁄4) + 3⁄4.

Where x. , _Xl , is the fitted sine function coefficient to be determined, which represents the equivalent of the generator set _βϊ .

Step S202, calculating a transient stability estimation index between the generator set and the generator set 3⁄4^, including step S2021 - step S2023:

Step S2021, according to the ^ variation trajectory fitting function ^, obtain the unstable equilibrium point _a after the fault removal, ^ is calculated as: ^^-arctan^^ - transient kinetic energy (acceleration area) ^ is:

■. ) + [ ^COS ( +3⁄4)- ^COS (3⁄40 + 3⁄4)]

(Deceleration area) v _TB is:

L ^COS ( _a + ^X 1) - ^COS (3⁄4c +

Among them, and . The unit power angle difference between the fault occurrence time and the fault removal time is indicated respectively.

Step S2023, as shown in the energy-type transient stability estimation index diagram shown in FIG. 9, the transient stability prediction index T _smj between the generator set and the generator set j is _{calculated as} : T _SEIij =1- .

Among them, the significance of the transient stability of the index is as follows, 3⁄4^>0 transient stability, _3⁄4 ^=0 critical transient stability, T _smj< Q, transient instability.

Step S203, sequentially calculating 3⁄4^ of any lead and lag unit pairs in the set Ω, and using the minimum unit pair as the transient stability prediction index STM of the current time domain data, the STM calculation formula is: S _TEI = Mm{r _s ^, , Ω}.

The method for obtaining the grid node voltage holding rate in step S3 includes:

Given the range of node voltage holding capacity in the transient process (lower voltage drop lower limit and duration), the number of nodes in the statistical system that meets the acceptable range of voltage levels in the transient process is calculated, and the node voltage is calculated in the transient process. The pass rate of retention ability ^ ^, ^ is calculated as: ^= .

The method for obtaining the thermal stability rate of the line in the power grid in step S3 includes: the static stability margin index and the line thermal stability of the given transient process: the node static stability margin _c , the line thermal stability limit ^ << ^ and duration, the number of nodes sustainable statistical power grid to meet the static stability range of ^ meet sustainable stability range of the number of hot line ½w, compute nodes static stability and thermal stability of the line S _ra passing rate of the transient process, The formula for _Ra is: ^S "" ^+L

In step S3, the overall transient stability situation of the power grid is obtained = « ₂ STM + + Among them, " ₂ , β-, and ₂ are the weight coefficients of the grid according to thermal stability constraints, operating electrical quantity constraints and static stability constraints, which can be flexibly configured according to experience or analysis needs. " ₂ , Α, ^ meet the following conditions:

S _TI can comprehensively measure the transient transient situation level of the current transient process information, and effectively quantify the stable situation of multiple transient faults.

It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be The invention is to be construed as being limited to the scope of the appended claims.

Claims

Rights request

A method for online quantitative integration assessment of a full-scale potential of a large power grid based on response, wherein the evaluation method comprises:

Step Sl, obtaining grid topology information from the SCADA system and the EMS system, and establishing a correspondence relationship with the WAMS system grid component;

2. The method of claim 1, wherein the various grid static response data comprises a predicted state offline traffic flow, a Nl, N-2 power flow convergence calculation result, a SCADA\EMS system state estimation result, and a PMU measurement information. ;

3. The method according to claim 1, wherein, in the step S3, the static stable situation assessment and the transient stability situation assessment are performed on the power grid, and all nodes of the power grid are allocated according to the number of parallel machines;

According to the power flow running section information combined with the power grid topology structure, the equivalent transmission power of each node is obtained according to the active flow direction. The tracking parameter identification method based on local measurement is used to identify the equivalent transmission model parameters of the current state of each node of the power grid. The equivalent transmission model parameters include the equivalent power supply potential ^ ^, the equivalent branch impedance mode, and the impedance angle "to achieve the node equivalent transmission model back mapping based on the current operating state of the grid.

4. The method according to claim 3, wherein the method for obtaining the generator stability margin index, the line stability margin indicator, and the node stability margin indicator of the power grid in the step S3 is:

According to the idea of maximum transmission power, the static stability margin index corresponding to the current operation mode of the generator branch, the tie line branch or the node is obtained for the generator branch, the tie line branch and the node equivalent transmission model respectively. Calculation

Where ZL represents the equivalent load impedance of the generator branch, tie line or node, and is obtained from the terminal voltage and power.

The method according to claim 3, wherein the method for obtaining the heat stability rate of the generator of the power grid and the thermal stability rate of the tie line in the step S3 comprises:

According to the thermal stability operation constraints of each generator and tie line itself, the statistical heat stability pass rate of the generator ^^ and the line thermal stability pass rate _R are: G _PR ., L _PR f .,

Among them, G _N and _W are the total number of generators of the grid, the total number of tie lines, and G _QN , respectively, the number of generators and tie lines that meet the thermal stability constraints of their respective operations;

The method for obtaining the node voltage pass rate and the load node power factor pass rate of the power grid in the step S3 includes: the node voltage and the load node power factor qualified range upper and lower limits according to the normal operation mode of the power grid, and the statistical power grid p

Node voltage pass rate load node power factor pass rate 4 ^R QFN where are the total number of nodes of the grid and the number of load nodes, respectively, V _QN , P _e are the number of nodes satisfying the voltage range and the number of load nodes satisfying the power factor range;

The method for obtaining the static stability rate of the power grid includes:

Set i an early warning threshold c, and count the number of all tie line branches and node equivalent branches greater than c in the grid. The nodes include generator nodes, intermediate contact nodes and load nodes, respectively calculate the line static pass rate _R. =^, node static stability rate Ns _{R :}

Where L _N N _N is the total number of contact lines and the number of nodes of the system respectively, and L _CN N _CN is the number of contact lines and the number of nodes greater than &c respectively.

The method according to claim 5, wherein the method for obtaining the overall static stability situation comprehensive index of the power grid in the step S3 comprises:

Overall grid static stability situation comprehensive indicator = «ι3⁄4 + IRQR + XiS _SR ,

Among them, _ai and AA are the weight coefficients of the grid according to thermal stability constraints, operating electrical quantity constraints and static stability constraints. According to experience or analysis, flexible configuration, AA, meets:

^^ is the overall thermal stability rate of the grid, ^^ calculation

The formula is: Η' QR

^G N + N

+ P ¹ QFN

Λ is the electrical capacity pass rate of the overall operation of the grid, R _QR calculation formula is: ^R QR

N _AI

■N,

Λ is the overall static stability rate of the grid, s, : The calculation formula is: S,

7. The method according to claim 3, wherein the method of virtual reactive power change is used in the step S3 to determine the reactive power required to minimize the active loss of the equivalent power transmission model, and obtain the current status of each node. The method of reactive power compensation level indicator in operation mode is:

Combining the equivalent transmission model of each node and its equivalent transmission active power A, the reactive power value 2 required for the minimum active loss corresponding to the flow A under the node equivalent model is obtained, and then the obtained and the obtained The node equivalent power transmission reactive power & is obtained, and the reactive power deficiency indicator a is obtained under the current operation mode of each node:

The method according to claim 3, wherein in the step S3, the time domain data of the grid transient process trajectory is obtained from the WAMS system or various expected transient fault sets, and the severely disturbed unit pair is directly used. The method includes an analysis of the transient behavior of the grid, and obtains the transient stability margin indicator of the grid, including steps S101-S103:

And S-side electromagnetic change of active power before and after the time of ¾ _E, victim relatively quickly identify the most advanced and most retarded X X stage generator, constituting the most serious disturbances relative unit set [Omega];

Step S102, calculating a generator set and a generator for any one of the lead and lag unit pairs in the set Ω Transient stability margin index between groups j T _SIij = ^-^;

Wherein, the difference between the power angles between the generator set and the generator set ', δ "δ S is the mechanical power function between the generator set i and the generator set j and the electromagnetic active power ^ ^ The intersection point is a virtual stable equilibrium operating point;

Step S103, sequentially calculating the transient stability margin indicator ⁷ ^ · between any lead and lag generators and the generator set ' in the set Ω, and using the minimum unit pair ⁷ ^ as the transient of the current time domain data The stability margin indicator STM, ie 5TSI = min r _siij , i, je Ω|.

9. The method of claim 8, wherein the calculating the method comprises the step S1021 - step S1023:

Step S1021, the inertia time constant of the equivalent single rotor between the generator set and the generator set ' is Μ, .Μ,.

M _eq =^-^, calculating a mechanical power function ij ^Pueq between the genset and the genset j

^PMJ ;

Where M and Mj are the inertia time constants of the generator set i and the generator set j, respectively, P _Mi and P _Mj are the mechanical injection power of the generator set and the generator set respectively, and the mechanical injection power of the generator set = M

² + B ² , ^A = Dcos(Sj - ) + Ecos( _l - B = D sin(3⁄4. -Θ^-Ε sin( .—θ〗, C = tan , u; , Uj, θ; _Xi , separate table

Show the generator bus voltage amplitude, phase angle and equivalent internal reactance of the generator set and generator set ';

In step S1023, 5 _seq = «sin(^) - C is calculated.

10. The method according to claim 8, characterized in that, for any pair of lead and lag units in the set Ω, according to the calculated unit, the equivalent mechanical power P _Meq and the electromagnetic active power 3⁄4 _q change trajectory are utilized. The curve fitting technique constructs the transient stability prediction index from the energy point of view, and specifically includes steps S201-S203:

Step S201, assuming that the equivalent mechanical power of the genset is unchanged during the transient process, the genset is fitted with the following sinusoidal function for the equivalent electromagnetic active power trajectory: ^ = sin( +3⁄4 ) + 3⁄4;

Step S202, calculating a transient stability prediction index T _SEIij between the generator set i and the generator set j;

Step S203, sequentially calculating the 3⁄4^ of any lead and lag unit pairs in the set Ω, and using the minimum unit pair as the transient stability prediction index STM of the current time domain data, ST _EI = min{r _s£/ ,,

Step S2021, determining an unstable equilibrium point _a after the fault removal according to the ^^ variation trajectory fitting function, where the unstable equilibrium point is the equivalent mechanical power of the generator set and the electromagnetic active power ^^ change rail The intersection of the lines, 5 _{iju is} calculated as: S _iju =n-wcX^x ^{PMeq 3⁄4} - _ι; In step S2022, the transient kinetic energy of the pair of units at the time of the fault removal is:

V _TA = J

The critical potential energy (deceleration area) absorbed by the system after fault removal is:

S ⁱⁿ ( + ) + _ P _Meq ^

[ ^COS ( . _a + 3⁄4 ) " COS( _3⁄4 + 3⁄4)

Among them, and . The difference between the power angles of the units indicating the time of occurrence of the fault and the time of the fault removal;

Step S2023, calculating the transient stability estimation index between the generator set and the generator set '

Among them, the meaning of the transient stability of ^ / index is: 3⁄4^>0 transient stability, _3⁄4 ^=0 critical transient stability, T _{smj <} Q, transient instability.

The method according to claim 10, wherein the method for obtaining the grid node voltage holding rate in the step S3 comprises:

The range of node voltage holding capacity in a given transient process: the lower limit and duration of the voltage drop, the number of nodes in the statistical grid that all nodes meet the acceptable range of voltage levels in the transient process, and calculate the node power in the transient process.

V,

The rate of compliance with the ability to maintain the capacity ^ «

The method for obtaining the thermal stability rate of the line in the power grid in the step S3 includes: determining the static stability margin index and the line thermal stability of the node during the transient process: the node static stability margin limit & _c , the line heat The stability limit ^ « and the duration r _c , the number of nodes that the statistical grid meets the static and sustainable range ^, the number of lines satisfying the thermal stability and sustainable range 1⁄2w, calculate the static stability of the node and the thermal stability of the line during the transient process The pass rate s _ra , S _{RA is} calculated as: S _TR ^{+ LQN} .

The method according to claim 11, wherein in step S3, the overall transient stability situation comprehensive index of the power grid is obtained = « ₂ S _TEI + β ₂ ν _τκ + _ZL S _M ;

Among them, " ₂ , A, respectively, the weight coefficient of the grid according to thermal stability constraints, operating electrical quantity constraints and static stability constraints, flexible configuration according to experience or analysis, " ₂ , A, ₂ meet:

≤1