The Adaptable System guard method of electric power system
One, technical field
The invention belongs to power system stability emergency control field; relate to the Adaptable System guard method of electric power system; be the method for the adaptive stabilizing protection system of the online decision-premaking of a kind of electric power system, periodically update the method for the self adaptation emergency control system of decision table by actual condition.
Two, background technology
From viewpoint economic and reality, the prevention and control of electric power system are always unfeasible and/or enough.For the serious accident of small probability, the back takes place and adopts the emergency control control that may employ prevention than in advance more reasonable in accident.
Existing emergency control decision scheme has following several scheme:
First kind is real-time numerical procedure, and its scheme is the operating mode X according to reality
1, and actual fault Y
1, with the real-time calculation control amount of fast algorithm.The amount that obtains like this is fully at actual conditions, its advantage is except the error of algorithm and online data itself, do not have other additional error, its deficiency is that the requirement algorithm has super real-time speed and enough precision and robustnesses, has far exceeded present technical merit again.
Second kind is to measure in real time to accompany by the real-time prediction scheme, but its decision scheme does not have to solve how to come the threshold values of given judgement unstability according to concrete situation, how to optimize decision-making.
The third is that off-line calculates the online in real time matching scheme in advance, and the calculated off-line burden of this scheme is very heavy, needs more than 10,000 decision table as west of Liaoning regional stability control system.On the other hand, the electrical network operating mode still may mismatch during online application.Its consequence be otherwise control system at a loss as to what to do, perhaps Kong Zhi effect extreme difference, perhaps unnecessary interruption of power supply.
Whole emergency control process comprises telecommunication, decision-making and enforcement, must finish in a very short time interval (for example 200ms).Both at home and abroad existing stable emergency control system extensively adopts " calculated off-line decision table, coupling in real time " scheme, also is that off-line is ready to decision table, with preassigned operating condition and the accident conditions index as table.In case detect a certain accident, do approximate match with the index of actual operating mode and accident conditions and decision table, pick out control strategy.This scheme needs a large amount of calculated off-line, and very poor to the flexibility of system change, and on the one hand, the information that off-line analysis provides is difficult to cover the whole operating conditions that run in the actual motion, and on the other hand, the coupling of real-time working condition still may be failed.Therefore, the situation that tripping or measure are exaggerated in the use is very serious.In addition, even only consider common operational mode, an area control system also may need the amount of calculation of several ten thousand decision tables and several man-years, in case and newly-increased power plant of system or power transmission line, original decision table will cancel.The merit angle or the accelerating power of other system real-time tracking this locality, but the critical value of but having avoided them is with operating mode, fault, computation model and control measure and the key issue that becomes.Because critical value is fixed or still relies on off-line and calculates in advance, therefore can not say so and calculate in real time, can not say so has adaptive ability.Some foreign study work is used calculated off-line decision table scheme and when running into the situation of online operating mode mismatch, simply external system is treated to infinite bus, and the online decision table of playing by ear that calculates is in advance separated with the nothing of avoiding control system, obviously this also adaptive ability out of the question, owing to can not accomplish really that then desirable self adaptation emergency control system is difficult to for it in line computation.
EEAC (expansion homalographic criterion) is a kind of transient stability rapid analysis method of the present application people invention.It is known as one that has online application prospect in direct method three major sects most by consistent in the world, and it is the only direct method that can find the solution multimachine system stability with the analytic approximation formula, also is the only up to now direct method that obtains strict proof.
Since EEAC came out from 1986, static (SEEAC), dynamic (DEEAC) and integrated (IEEAC) three phases have been experienced.Delivered more than 30 piece of international paper about SEEAC and DEEAC, extensively quoted, elected as graduate text abroad by this area, and by specially chapter introduction of internal authority monograph conduct.Its early stage achievement has obtained the approval of electric power enterprise in the practical engineering application of China and system of Electricite De France.Another part patent application that the applicant proposes has provided the present situation that EEAC uses in description of the Prior Art.
But also there are following problem in SEEAC and DEEAC: (1) can only reflect the stability (other direct method all can only reflect first pendulum stability now) of first pendulum and the 2nd pendulum, can't handle plurality of pendulums stability; (2) comprise that with current all methods numerical integrating is the same, all can't handle isolated stable region phenomenon; (3) precision and the contradiction between speed to first pendulum stability solves desirablely not enough; (4) for complex model, above-mentioned contradiction is more outstanding, to such an extent as to EEAC no longer has the obvious speed advantage for numerical integrating.
Can overcome above-mentioned difficulties with IEEAC, and in the China Power system, pass through the test that engineering is used.The major technique content of relevant IEEAC is still a flight data recorder, unexposed mistake till the application's day.But in another part application for a patent for invention book that has proposed (95110947 " method of the in-service monitoring of electric power system transient stability and prevention and control system "), detailed description is arranged.
Three, summary of the invention
The objective of the invention is to utilize IEEAC fast the go forward side by side characteristics of line sensitivity analysis of calculation stability nargin assess the effect and the limiting value of various emergency control measures.Because can the on-line tracing actual condition, calculate whole forecast failures in the short period of time and refreshed decision table, thousands of irrelevant operating modes just needn't occur in decision table again, have so not only avoided a large amount of calculated off-line, and have farthest utilized all quasi real time information.Say in this sense, also just do not have the possibility of operating mode mismatch certainly.
Be published in domestic by what the present inventor proposed in nineteen ninety about the online tentative programme of calculating the emergency control system of the real-time coupling of decision table in advance, be published in the world in 1993, stable down directly analysis still will rely on a large amount of calculating of off-line to extract knowledge but this scheme is for complex model, and feasibility is relatively poor; On the other hand, the quality of knowledge of expert system has directly influenced control precision, and therefore the robustness of decision-making is bad.New departure of the application has solved the problems referred to above well, and its technical scheme and details were not separated yet.
The technology of the present invention is a kind of Adaptable System guard method of electric power system, and this method comprises the following steps:
(1) gathers the information on the spot of electric power system with the real-time data acquisition device, and gather actual condition information with EMS;
(2) according to the plan predicted value of above-mentioned information and shortage real time data, obtain system-wide real-time working condition value;
(3) at resulting operating condition value, adopting integrated expansion homalographic criterion method automatically various incipient faults to be carried out engine sta bility margin calculates, determine the limiting value of various emergency control measures, selection can make that system can stablize when in a single day this fault takes place, and the minimum emergency control measure of control cost, obtain online decision-premaking table, and upgrade the control measure decision table in the real-time coalignment of fault;
(4) detection failure constantly, in case there is fault to take place, by this fault message the control measure decision table is mated in real time, from this table, find and the corresponding emergency control measure of this fault, and to each on the spot final controlling element send control command, implement the emergency control measure.
Nargin in above-mentioned the 3rd step calculate and emergency control measure limiting value determine comprise the steps:
(1) gets rid of extremely stable fault with the integrated expansion homalographic criterion method of classical model, and produce the relevant critical map, stability margin of other faults and for the sensitivity coefficient of important control amount;
(2) handle complex generator model and load model with dynamic expansion homalographic criterion method, get rid of extremely stable fault once more, and judge whether to exist plurality of pendulums unstability and isolated stable region;
(3) determine the limiting value of emergency control measure with the integrated expansion homalographic criterion method of detailed model.
The online updating of decision table of the present invention can adopt to distribute and calculate, and wherein the scheduling to many CPU is unit with the fault scenes.The present invention's step more specifically is as follows: utilize integrated expansion equal-area method (IEEAC) in electric power system, by the online decision table that periodically updates of actual condition, and need to search the adaptive stabilizing control system that decision table is also implemented by the physical fault situation following of the state of emergency.By the data acquisition watchdog subsystem of special use, the on-line decision subsystem, control is implemented subsystem and is constituted on the spot or zonal emergency control system, and with the online exchange message of existing EMS.(1) during online budgeting decision table, the actual condition information that the information on the spot of utilizing exclusive data harvester on the spot to obtain, and EMS as far as possible gathers then adopts the plan predicted value automatically to the amount that lacks real time data; (2) different with the application of planning type and prevention and control type, not notion, but directly instruct decision-making with later stability margin (η) notion of standardization by critical clearing time or other critical parameters.(3) utilize IEEAC, under required model, select the emergency control decision-making of the required employing of each forecast failure.Earlier get rid of extremely stable scene, and provide relevant critical map OMIB (to be designated as R other scene with the IEEAC under the classical model (CM)
1(CM)), and variation σ (CM) at that time, stability margin η is to the approximate sensitivity coefficient of important controlled quentity controlled variable X, and whether may have useful informations such as plurality of pendulums unstability and isolated stable region.Consider the influence of complex generator model and load model again with DEEAC, obtain complex model and be the increase of the kinetic energy under actual mute time area A
IncReach the η when not adding control,, then can finish analysis this fault scenes if η is enough big and σ is enough little.If η is big, but σ is also big, then needn't consider stringent effort, directly enters plurality of pendulums and checks.When (4) the emergency control measure of an anticipation being assessed, only need constantly begin to do the integration mapping, till equivalent angle is returned or run into dynamic saddle point, calculate kinetic energy retardation area A from the control input
DecPress gained η=A
Dec-A
IncValue judges whether this measure is not enough or undue.(5) the multimachine integration to the generator model of complexity adopts each machine E
QiThe scheme of piecewise constant, thus can be with the high stage labor series expansion of variable step., and will load and the complex model of other network-type element is treated to constant-impedance piecemeal with the long integration of small step to the dynamical equation of controller.(6) with σ (DM)=η
DE(DM)-η
SE(CM)/η
SE(CM) reflect the time range degree of complex model OMIB map, wherein η
DE(DM) and η
SE(CM) correspond respectively to the static EEAC (SEEAC) under the dynamic EEAC (DEEAC) and classical model (CM) under the complex model (DM).If σ (DM) is too big, then to check whether possible oppositely plurality of pendulums unstability; If σ (DM) is negative very greatly, then to checks whether forward plurality of pendulums unstability may take place.Handle deep knowledge with expert system technology, accelerate the speed of decision-premaking, but directly do not influence decision accuracy.These effects are included in the computational process partial relaxation to the requirement of complex model, propose the initial value suggestion, propose the exploration strategy to various control measure, discern the possibility of potential plurality of pendulums unstability and isolated stable region.For the speed of quickening the online updating decision table can adopt the distribution computing technique, its task scheduling is unit with the fault scenes.Its job step is divided into online budget and mates two parts in real time.In the online environment, constantly calculate suitable emergency control measure by work information of gathering in real time and predefined fault scenes with IEEAC, and deposit decision table in, in case detect the fault that electric power system takes place, just can table look-up by fault message obtains the measure that should take and automatically performs.It is both realized can be at local emergency control, also can be at regional emergency control; The calculating of bug list can be carried out in a CPU in serial, also can walk abreast in a plurality of CPU and carry out.
Any to be expected practical stability analysis method all faster than current for EEAC, and guaranteed its precision and reliability from principle.The work station of a 20MIPS can be finished the example of 20 stable control decisions to complicated electric power system in 5 minutes.This has just created condition for the method for desirable online updating decision table.
Four, description of drawings
Fig. 1 has provided the hardware configuration block diagram of main station system in the existing stabilization control device, the last bit processing machine of main website is made of three groups of microcomputers, the data processing of every group of microcomputer and accident treatment program are identical, microcomputer 3 is master processors, double as ruling machine carries out getting in three two voting, and the management of responsible panel, output print is communicated by letter with PC etc.
Preprocessor is finished the sampling and the calculating of ac input signal, reading in of switching value input signal, start differentiation, fault-free trip differentiation, PT, CT loop anomalous discrimination, and with the result in exchanges data bus, bus interface board are delivered to the bus interface board of up-computer part.The AC converter is transformed to the weak signal that is suitable for the preprocessor sampling to voltage signal, the current signal of input, the line amplitude of going forward side by side adjustment and phase compensation, and the sequential plate is with the crystal oscillator frequency division and produce clock signal, and bus interface board is used for data/address bus and bus interface.
Fig. 2 is the schematic diagram of adaptive stabilizing protection system (in the empty frame).
Fig. 3 is the processing method program block diagram of industrial control computer to the fault scenes decision-premaking.
Five, embodiment
Below with example invention is described in detail with reference to the accompanying drawings.
The structure chart of Fig. 1 can continue to be used.By communicating by letter or compunication with the telemechanical of EMS (EMS), get external information as much as possible, the total generating and the total load amount of system and each subregion should be arranged at least, and necessary topology network information.Local real time information is also directly imported this protective device.Any that might obtain and all should be retained in the computation model as far as possible, when failing once in a while to obtain the instantaneous value of certain amount for some reason, continue to use sub-value, but behind certain hour, adopt corresponding planned value automatically.These online information and planned value reflect the data of actual condition in the periodic refresh database after information processing.Cooperation layer expert system ES manages several parallel Industrial Control Computers, and the stringent effort under each forecast accident are made decisions.Calculation task is to be that unit distributes to each Industrial Control Computer with the forecast accident, and the decision-premaking that the latter makes returns to ES, the unified decision table of filling in.Several Industrial Control Computers PCU
1-CPU
nPress the IEEAC algorithm and upgrade decision table, table 1 and table 2 are born forward and backward decision table in turn, and the content of foreground table is sent to table 3 for real-time event border coupling usefulness, and the backstage table then is in update mode.After fault is detected, in table 3, finds corresponding decision-making (as cutter, cutting load, quick closing valve porthole etc.) measure immediately and implement it.
Each Industrial Control Computer is responsible for the decision-premaking of a fault scenes at every turn, and Fig. 3 is its handling process, and the dotted line left side is the expert system part, and the right side is an EEAC algorithm part.Industrial Control Computer is to upper strata ES
0Get after the fault scenes, instruct the EEAC budget of making a strategic decision with ESi, and after finishing to ES
0Report decision-making content.
Critical group (CC), the critical clearing time t of (1) frame under SEEAC (CM) the calculating classical model
eAnd the time variation σ (CM) of map OMIB.The extremely stable scene of (2) frame elimination is promptly only just further calculated when stablizing inadequately.(3) frame with DEEAC (DM) calculation of complex model in the physical fault mute time and do not add η and A under the control situation
IncThe sufficiently stable fault scenes of the further filtering of (4) frame, and by the priority of the reserve control measure that may adopt and the emergency control measure X of sensitivity information recommendation tentative calculation.(5) frame calculates corresponding A at this control with DEEAC (DM)
Dec(X), η (X) and d η/dx value.(4) frame will advise attempting according to this next time, till η (x) is in satisfied interval, at this moment, will predict the possibility that whether have plurality of pendulums and isolated stable region by (6) frame, if having, then search for modified chi by (7) frame with IEEAC (DM).
The applicant has carried out a large amount of feasibility analyses for an emergency control system of Zhejiang electrical network, and its technical performance obtains the approval of Subscriber Unit.Further implement in progress.
In a word, the invention provides a kind of self adaptation emergency control system of bringing in constant renewal in decision table by the electric power system actual condition.System condition information that gather by this locality and that periodically send here from EMS, with expansion homalographic criterion (EEAC) online definite each forecast failure (symmetry or unbalanced fault, can take into account single-pole reclosing) under the emergency control measure, and deposit decision table in.In case break down, then from table, find out local or regional control measure such as corresponding quick closing valve, cutter, cutting load and off-the-line, and implement these measures by corresponding controller.
Because the accuracy of the present invention the is integrated rapidity of EEAC and sensitivity analysis ability, numerical integrating and set up the intelligent of expert system on the deep knowledge, a large amount of irrelevant calculated off-line and the mismatch error between the actual working conditions have not only been avoided, and expansion to electric power system, online information delete benefit, the variation of control appliance kind and quantity, and the change of mathematical models of power system all had fabulous adaptability and robustness.On the other hand, this emergency control system also has modularization good, adapts to property production in batches, with short production cycle and advantage that life cycle is long.To what put into operation, the emergency control system of making a strategic decision by the off-line budget also only needs to change the software relevant with decision table, just can obtain above-mentioned advantage, and not need to upgrade main hardware device.