CN109193701A - Electric system low-limit frequency calculation method and device under high-power missing - Google Patents
Electric system low-limit frequency calculation method and device under high-power missing Download PDFInfo
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- CN109193701A CN109193701A CN201811197115.9A CN201811197115A CN109193701A CN 109193701 A CN109193701 A CN 109193701A CN 201811197115 A CN201811197115 A CN 201811197115A CN 109193701 A CN109193701 A CN 109193701A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J5/00—Circuit arrangements for transfer of electric power between ac networks and dc networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
Abstract
The invention discloses electric system low-limit frequency calculation method and devices under high-power missing, this method includes construction step, it is primary to simplify step, secondary simplified step, analyzing step, in conjunction with the physical process of the related content analysis frequency response of primary frequency modulation in frequency control system, frequency variation tendency after qualitative analysis disturbance, construct multi-computer system frequency response equivalent model, frequency of use feedback is unlinked and unit frequency response characteristic is fitted two kinds of Model Simplification Methods and simplifies to complicated multi-computer system, the time-domain expression of low-limit frequency and its corresponding time is derived using analytic method, electric system low-limit frequency is calculated simple and practically, and then preferably cooperated by quantitative analysis realization with relay protection, improve the execution speed of frequency response, change frequency fluctuation transient process, to avoid the generation of the accidents such as low-frequency load shedding , realize and better ensure that system frequency is stable, maintains the stable operation of electric system.
Description
Technical field
The present invention relates to electric system low-limit frequencies under the technical field of electric system more particularly to high-power missing to calculate
Method and device.
Background technique
It is gradually increased with the new-energy grid-connecteds amount such as wind-powered electricity generation, photovoltaic, electric system disturbance rejection gradually decreases；In addition extra-high voltage
AC-DC hybrid power grid development molding causes high-power miss fault probability to increase, and power system frequency stable problem is increasingly tight
Weight.
Under high-power missing it is of greatest concern be frequency fluctuation minimum point, whether determining the starting of low-frequency load shedding because of it.
It, will be greatly if the execution speed of frequency response can be improved during this period since frequency fast fall time is of short duration after disturbance
Change frequency fluctuation transient process, to avoid the generation of the accidents such as low-frequency load shedding, realization better ensure that system frequency it is stable,
The purpose of maintenance system operational safety.
Low-limit frequency is predicted after patent CN108090615A discloses the electric power system fault based on cross entropy integrated study
Different types of transient fault is arranged by emulation in method, this method；Algorithm off-line training is carried out according to data sample；By more
The cross entropy of a base learner is calculated integrated study model and carries out the frequency predication after line failure.Although this method also can
Low-limit frequency after prediction electric power system fault, but the calculating that machine learning needs to expend flood tide to reach enough accuracy provides
Source, required higher cost.
Summary of the invention
For overcome the deficiencies in the prior art, the purpose of the present invention is to provide electric system lowest frequencies under high-power missing
Rate calculation method and device, it is intended to solve the reduction of electric system disturbance rejection, high-power miss fault probability increases, electric system
The problem of frequency stabilization problem is got worse.
The purpose of the present invention is implemented with the following technical solutions:
Electric system low-limit frequency calculation method under a kind of high-power missing, comprising:
Construction step constructs the frequency response equivalent model of multi-computer system；
It is primary to simplify step, it is unlinked using feedback and its linear method unlinks to frequency response equivalent model, it will be more
The control of machine system feedback is changed into feedforward control, and calculates the equivalent inertia and original frequency fall off rate of multi-computer system；
Secondary simplified step calculates open-loop gain and the response time of governor model, by machines all types of in multi-computer system
Group governor Approximate Equivalent is first order inertial loop, is simplified again to frequency response equivalent model；
Analyzing step utilizes Generation Side and load side in conjunction with the equivalent inertia and original frequency fall off rate of multi-computer system
Active balance, obtain the frequency response dynamic process expression formula of frequency response equivalent model using analytic method, approximation obtains temporary
State frequency minimum point is as electric system low-limit frequency under high-power missing.
On the basis of the above embodiments, it is preferred that the primary simplified step, specifically:
It unlinks at feedback and to simulate frequency difference as the input terminal of all kinds of machine unit speed regulating devices of multi-computer system, multi-computer system
Feedback fraction is converted into all kinds of units under identical frequency difference input and responds the simple linear superposition for obtaining power, multimachine by governor
System frequency value is consistent, and after unlinking all kinds of machine unit speed regulating devices inputs frequency difference it is also consistent；
The net inertia constant H of multi-computer systemnetAre as follows:
Wherein, Stotal-VAFor total specified complex power in electric system, m is the generator sum for being linked into electric system,
Sn-VAFor the specified complex power of n-th generator, HnFor the inertia constant of n-th generator, 1≤n≤m, n, m are positive integer；
With the net inertia constant H of multi-computer systemnetEquivalent inertia as multi-computer system；
When one timing of power shortage, enabling load end frequency variation is Δ PL, multi-computer system frequencies omega after being disturbed
The relationship expression of variation delta ω and time t are as follows:
Then Δ ω (t) ≈-mΔω·t；
WithOriginal frequency fall off rate as multi-computer system.
On the basis of the above embodiments, it is preferred that in the secondary simplified step, again to frequency response equivalent model
It carries out after simplifying, governor response meets:
Wherein, Δ PGiIt (s) is the output power of i-th of dynamo governor, s is plural number, KiIt is adjusted the speed for i-th of generator
The open-loop gain of device, TiFor the response time of i-th of dynamo governor, 1≤i≤m, i are positive integer.
On the basis of the above embodiments, it is preferred that in the analyzing step, frequency is obtained by inverse Laplace transformation
Respond the frequency response dynamic process expression formula of equivalent model are as follows:
Because meeting when power-balance:
Wherein, load end frequency variation Δ PLFor power disturbance；
Frequency minimum point time tminMeet:
Then Δ ωmax≈-mΔω·tmin；
According to Δ ωmaxElectric system low-limit frequency under high-power missing is calculated.
On the basis of above-mentioned any embodiment, it is preferred that in the secondary simplified step, calculated using least square method
The open-loop gain of governor model and response time.
Electric system low-limit frequency computing device under a kind of high-power missing, comprising:
Module is constructed, for constructing the frequency response equivalent model of multi-computer system；
It is primary to simplify module, for being unlinked using feedback and its linear method unlinks to frequency response equivalent model,
Multi-computer system feedback control is changed into feedforward control, and calculates the equivalent inertia and original frequency fall off rate of multi-computer system；
Secondary simplified module will be all kinds of in multi-computer system for calculating open-loop gain and the response time of governor model
Type machine unit speed regulating device Approximate Equivalent is first order inertial loop, is simplified again to frequency response equivalent model；
Parsing module using Generation Side and is born for combining the equivalent inertia and original frequency fall off rate of multi-computer system
The active balance of lotus side obtains the frequency response dynamic process expression formula of frequency response equivalent model using analytic method, and approximation obtains
Transient frequency minimum point is obtained as electric system low-limit frequency under high-power missing.
On the basis of the above embodiments, it is preferred that the primary simplified module is used for:
It unlinks at feedback and to simulate frequency difference as the input terminal of all kinds of machine unit speed regulating devices of multi-computer system, multi-computer system
Feedback fraction is converted into all kinds of units under identical frequency difference input and responds the simple linear superposition for obtaining power, multimachine by governor
System frequency value is consistent, and after unlinking all kinds of machine unit speed regulating devices inputs frequency difference it is also consistent；
The net inertia constant H of multi-computer systemnetAre as follows:
Wherein, Stotal-VAFor total specified complex power in electric system, m is the generator sum for being linked into electric system,
Sn-VAFor the specified complex power of n-th generator, HnFor the inertia constant of n-th generator, 1≤n≤m, n, m are positive integer；
With the net inertia constant H of multi-computer systemnetEquivalent inertia as multi-computer system；
When one timing of power shortage, enabling load end frequency variation is Δ PL, multi-computer system frequencies omega after being disturbed
The relationship expression of variation delta ω and time t are as follows:
Then Δ ω (t) ≈-mΔω·t；
WithOriginal frequency fall off rate as multi-computer system.
On the basis of the above embodiments, it is preferred that the secondary simplified module again to frequency response equivalent model into
After row simplifies, governor response meets:
Wherein, Δ PGiIt (s) is the output power of i-th of dynamo governor, s is plural number, KiIt is adjusted the speed for i-th of generator
The open-loop gain of device, TiFor the response time of i-th of dynamo governor, 1≤i≤m, i are positive integer.
On the basis of the above embodiments, it is preferred that the parsing module obtains frequency by inverse Laplace transformation and rings
Answer the frequency response dynamic process expression formula of equivalent model are as follows:
Because meeting when power-balance:
Wherein, load end frequency variation Δ PLFor power disturbance；
Frequency minimum point time tminMeet:
Then Δ ωmax≈-mΔω·tmin；
According to Δ ωmaxElectric system low-limit frequency under high-power missing is calculated.
On the basis of above-mentioned any embodiment, it is preferred that the secondary simplified module is calculated using least square method and adjusted
The open-loop gain of fast device model and response time.
Compared with prior art, the beneficial effects of the present invention are:
The invention discloses electric system low-limit frequency calculation method and devices under high-power missing, in conjunction with frequency control volume
The physical process of the related content analysis frequency response of primary frequency modulation, the frequency variation tendency after qualitative analysis disturbance, structure in system
Multi-computer system frequency response equivalent model is built, frequency of use feedback is unlinked and unit frequency response characteristic is fitted two kinds of model letters
Change method simplifies complicated multi-computer system, derives low-limit frequency using analytic method and its time domain of corresponding time is expressed
Formula calculates electric system low-limit frequency simple and practically, and then is preferably cooperated by quantitative analysis realization with relay protection, mentions
The execution speed of high-frequency response, changes frequency fluctuation transient process, to avoid the generation of the accidents such as low-frequency load shedding, realizes more
Guarantee that system frequency is stable, maintains the stable operation of electric system well.
The present invention be able to use frequency feedback unlink method simplify multicomputer frequency response equivalent model input signal, will frequency
Rate response is changed into feedforward control by feedback control, frequency response calculation amount is reduced, when this hypothesis is conducive to high-power missing
Carve the assessment and interception of frequency fall off rate；It is various to water power, thermoelectricity etc. by using unit frequency response characteristic approximating method
Type unit is simplified, and carries out unification to its governor model, can reduce model solution complexity, to multi-computer system frequency
Rate response equivalent model is simplified；Can rapid solving multi-computer system transient frequency minimum point, can be frequency under high-power missing
Rate resource response calls configuration to provide guidance, and this method universality is strong, can be applied in the bulk power grid containing various energy resources, to reduction
Electric system low-frequency load shedding, off-the-line failure are of great significance under high-power missing.
Detailed description of the invention
Present invention will be further explained below with reference to the attached drawings and examples.
Fig. 1 shows a kind of frequency response equivalent model of multi-computer system provided in an embodiment of the present invention；
Fig. 2 shows simulation frequency difference input variation schematic diagrames after a kind of step disturbance provided in an embodiment of the present invention；
Fig. 3 shows the frequency response equivalent model for the multi-computer system that a kind of complex frequency domain provided in an embodiment of the present invention simplifies
Figure；
Fig. 4 shows electric system low-limit frequency calculation method under a kind of high-power missing provided in an embodiment of the present invention
Flow diagram；
Fig. 5 shows electric system low-limit frequency computing device under a kind of high-power missing provided in an embodiment of the present invention
Structural schematic diagram.
Specific embodiment
In the following, being described further in conjunction with attached drawing and specific embodiment to the present invention, it should be noted that not
Under the premise of conflicting, new implementation can be formed between various embodiments described below or between each technical characteristic in any combination
Example.
Specific embodiment one
In practical applications, power system network is collectively constituted by a certain percentage by a variety of units, it is therefore desirable to be improved
The flexibility and diversity of frequency control.
As shown in figure 4, the embodiment of the invention provides electric system low-limit frequency calculation method under a kind of high-power missing,
Include:
Construction step S101 constructs the frequency response equivalent model of multi-computer system；
It is primary to simplify step S102, it is unlinked using feedback and its linear method unlinks to frequency response equivalent model,
Multi-computer system feedback control is changed into feedforward control, and calculates the equivalent inertia and original frequency fall off rate of multi-computer system；
Secondary simplified step S103, calculates open-loop gain and the response time of governor model, will be all kinds of in multi-computer system
Type machine unit speed regulating device Approximate Equivalent is first order inertial loop, is simplified again to frequency response equivalent model；
Analyzing step S104 using Generation Side and is born in conjunction with the equivalent inertia and original frequency fall off rate of multi-computer system
The active balance of lotus side obtains the frequency response dynamic process expression formula of frequency response equivalent model using analytic method, and approximation obtains
Transient frequency minimum point is obtained as electric system low-limit frequency under high-power missing.
Preferably, in the secondary simplified step S103, the open loop that least square method calculates governor model can be used
Gain and response time.
It is simulation frequency difference input that feedback, which is unlinked and its linearized, by unlinking at feedback and using this frequency difference as respectively
The input terminal of class machine unit speed regulating device, complicated feedback fraction can be converted under identical frequency difference input in such multi-computer system,
All kinds of units respond the simple linear superposition for obtaining power by governor, and calculation amount greatly reduces.Ignore machine here
Between shake, therefore whole system frequency values are consistent；The frequency difference of all kinds of machine unit speed regulating device inputs is also identical after unlinking.Frequently
Rate feedback unlink make complicated incalculable multi-computer system and then the abbreviation that unlinks can be with the one-of-a-kind system of linear superposition by
A calculating, simulation frequency difference input then provide foundation to unlinking.But actual frequency variation is not linear, frequency change rate
And be gradually reduced, so certain error has also been introduced while unlinking.But compared to multi-computer system feedback fraction
Constantly superposition, this error is acceptable.Preferably, the primary simplified step S102, can be with specifically:
It unlinks at feedback and to simulate frequency difference as the input terminal of all kinds of machine unit speed regulating devices of multi-computer system, multi-computer system
Feedback fraction is converted into all kinds of units under identical frequency difference input and responds the simple linear superposition for obtaining power, multimachine by governor
System frequency value is consistent, and after unlinking all kinds of machine unit speed regulating devices inputs frequency difference it is also consistent；The frequency response of multi-computer system
Equivalent model is as shown in Figure 1, Δ PLFor load end frequency variation, Δ PGiFor the output power of i-th of dynamo governor,M is the generator sum for being linked into electric system, and s is plural number；
The initial rate of change size of power system frequency is Pstep/ 2H, as system power vacancy PstepOne timing, this value
It is only related with system inertia time constant H, correspond to multi-computer system, the H in Fig. 1 in rotor modulenetIt is full for net inertia constant
Sufficient relational expression:
Wherein, Stotal-VAFor total specified complex power in electric system, m is the generator sum for being linked into electric system,
Sn-VAFor the specified complex power of n-th generator, HnFor the inertia constant of n-th generator, 1≤n≤m, n, m are positive integer；
With the net inertia constant H of multi-computer systemnetEquivalent inertia as multi-computer system；
When one timing of power shortage, original frequency change rate is used as the frequency difference slope to be found to complete frequency feedback solution
Simulation frequency difference input in ring and its linearisation；It is assumed herein that load end frequency variation is Δ PL, multimachine system after being disturbed
The relationship expression of the variation delta ω and time t of frequencies omega of uniting are as follows:
Then Δ ω (t) ≈-mΔω·t；
WithOriginal frequency fall off rate as multi-computer system.
Frequency difference input is simulated after disturbance can be as shown in Figure 2, it can be seen that t=0 start frequency linear decline, that is, frequency
Change rate remains unchanged, and each moment frequency variation can be indicated by linearly after disturbance.
The high-power missing that electric system occurs suddenly causes system frequency to begin to decline, and it is exactly false for simulating frequency difference input
Determine before frequency drops to minimum point, frequency change rate is constant, and frequency variation is directly proportional to the time.This hypothesis is after interference
First moment is more accurate, and it is equal to the initial rate of change of frequency.Letter can be transmitted to multi-computer system by simulating frequency difference input
Number carries out processing of unlinking, and using the frequency difference signal of linear decline as input, calculates the response of each machine unit speed regulating device.
Because the governor module of the polymorphic types unit such as fired power generating unit is still very complicated, and all kinds of units are in the expression of complex frequency domain
Formula is not identical, approximate fits can be done to increasingly complex multi-computer system frequency response equivalent model, because of opening for governor model
Ring gain is similar to first order inertial loop, can do approximate fits by open-loop gain K=1/R and model response time T.Make simultaneously
The fitting parameter K and T of its simplified model are calculated with least square method.Multi-computer system frequency response equivalent model can simplify, such as Fig. 3
It is shown.Preferably, in the secondary simplified step S103, after simplifying again to frequency response equivalent model, governor is rung
It should can satisfy:
Wherein, Δ PGiIt (s) is the output power of i-th of dynamo governor, s is plural number, KiIt is adjusted the speed for i-th of generator
The open-loop gain of device, TiFor the response time of i-th of dynamo governor, 1≤i≤m, i are positive integer.
Preferably, in the analyzing step S104, the frequency of frequency response equivalent model is obtained by inverse Laplace transformation
Rate response dynamics procedure expression can be with are as follows:
Because meeting when power-balance:
Wherein, load end frequency variation Δ PLFor power disturbance；
Frequency minimum point time tminMeet:
Then Δ ωmax≈-mΔω·tmin；
According to Δ ωmaxElectric system low-limit frequency under high-power missing is calculated.
The physics mistake of the related content analysis frequency response of primary frequency modulation in combination frequency control system of the embodiment of the present invention
Journey, the frequency variation tendency after qualitative analysis disturbance, constructs multi-computer system frequency response equivalent model；Simplify process primary
In, it is unlinked using feedback and its linear method unlinks to multi-computer system model, before multi-computer system feedback control is changed into
Feedback control, and calculate the equivalent inertia of multi-computer system and original frequency fall off rate；During secondary simplification, least square is used
Method calculates open-loop gain and the response time of governor model, is one order inertia ring by all types of machine unit speed regulating device Approximate Equivalents
Section；The active balance for finally utilizing Generation Side and load side derives frequency response dynamic process expression formula using analytic method, approximate
Transient frequency minimum point is obtained as electric system low-limit frequency under high-power missing.Frequency of use of embodiment of the present invention feedback solution
Ring and unit frequency response characteristic are fitted two kinds of Model Simplification Methods and simplify to complicated multi-computer system, use analytic method
The time-domain expression for deriving low-limit frequency and its corresponding time, calculates electric system low-limit frequency, and then pass through simple and practically
Quantitative analysis realization preferably cooperates with relay protection, improves the execution speed of frequency response, changes frequency fluctuation transient process,
To avoid the generation of the accidents such as low-frequency load shedding, the stable fortune for better ensuring that system frequency is stable, maintains electric system is realized
Row.
In above-mentioned specific embodiment one, electric system low-limit frequency calculation method under high-power missing is provided, with
It is corresponding, the application also provides electric system low-limit frequency computing device under high-power missing.Due to Installation practice base
Originally it is similar to embodiment of the method, so describing fairly simple, the relevent part can refer to the partial explaination of embodiments of method.Under
The Installation practice for stating description is only schematical.
Specific embodiment two
As shown in figure 5, the embodiment of the invention provides electric system low-limit frequency computing device under a kind of high-power missing,
Include:
Module 201 is constructed, for constructing the frequency response equivalent model of multi-computer system；
It is primary to simplify module 202, for being unlinked using feedback and its linear method solves frequency response equivalent model
Multi-computer system feedback control is changed into feedforward control by ring, and calculates reduction of speed under the equivalent inertia and original frequency of multi-computer system
Rate；
Secondary simplified module 203 will be each in multi-computer system for calculating open-loop gain and the response time of governor model
Type machine unit speed regulating device Approximate Equivalent is first order inertial loop, is simplified again to frequency response equivalent model；
Parsing module 204, for combine multi-computer system equivalent inertia and original frequency fall off rate, using Generation Side with
The active balance of load side obtains the frequency response dynamic process expression formula of frequency response equivalent model using analytic method, approximate
Transient frequency minimum point is obtained as electric system low-limit frequency under high-power missing.
Preferably, the primary simplified module 202 can be used for:
It unlinks at feedback and to simulate frequency difference as the input terminal of all kinds of machine unit speed regulating devices of multi-computer system, multi-computer system
Feedback fraction is converted into all kinds of units under identical frequency difference input and responds the simple linear superposition for obtaining power, multimachine by governor
System frequency value is consistent, and after unlinking all kinds of machine unit speed regulating devices inputs frequency difference it is also consistent；
The net inertia constant H of multi-computer systemnetAre as follows:
Wherein, Stotal-VAFor total specified complex power in electric system, m is the generator sum for being linked into electric system,
Sn-VAFor the specified complex power of n-th generator, HnFor the inertia constant of n-th generator, 1≤n≤m, n, m are positive integer；
With the net inertia constant H of multi-computer systemnetEquivalent inertia as multi-computer system；
When one timing of power shortage, enabling load end frequency variation is Δ PL, multi-computer system frequencies omega after being disturbed
The relationship expression of variation delta ω and time t are as follows:
Then Δ ω (t) ≈-mΔω·t；
WithOriginal frequency fall off rate as multi-computer system.
Preferably, after the secondary simplified module 203 again simplifies frequency response equivalent model, governor response
It can satisfy:
Wherein, Δ PGiIt (s) is the output power of i-th of dynamo governor, s is plural number, KiIt is adjusted the speed for i-th of generator
The open-loop gain of device, TiFor the response time of i-th of dynamo governor, 1≤i≤m, i are positive integer.
Preferably, the parsing module 204 is rung by the frequency that inverse Laplace transformation obtains frequency response equivalent model
Answer dynamic process expression formula can be with are as follows:
Because meeting when power-balance:
Wherein, load end frequency variation Δ PLFor power disturbance；
Frequency minimum point time tminMeet:
Then Δ ωmax≈-mΔω·tmin；
According to Δ ωmaxElectric system low-limit frequency under high-power missing is calculated.
Preferably, the open-loop gain that least square method calculates governor model can be used in the secondary simplified module 203
With the response time.
The physics mistake of the related content analysis frequency response of primary frequency modulation in combination frequency control system of the embodiment of the present invention
Journey, the frequency variation tendency after qualitative analysis disturbance, constructs multi-computer system frequency response equivalent model；Simplify process primary
In, it is unlinked using feedback and its linear method unlinks to multi-computer system model, before multi-computer system feedback control is changed into
Feedback control, and calculate the equivalent inertia of multi-computer system and original frequency fall off rate；During secondary simplification, least square is used
Method calculates open-loop gain and the response time of governor model, is one order inertia ring by all types of machine unit speed regulating device Approximate Equivalents
Section；The active balance for finally utilizing Generation Side and load side derives frequency response dynamic process expression formula using analytic method, approximate
Transient frequency minimum point is obtained as electric system low-limit frequency under high-power missing.Frequency of use of embodiment of the present invention feedback solution
Ring and unit frequency response characteristic are fitted two kinds of Model Simplification Methods and simplify to complicated multi-computer system, use analytic method
The time-domain expression for deriving low-limit frequency and its corresponding time, calculates electric system low-limit frequency, and then pass through simple and practically
Quantitative analysis realization preferably cooperates with relay protection, improves the execution speed of frequency response, changes frequency fluctuation transient process,
To avoid the generation of the accidents such as low-frequency load shedding, the stable fortune for better ensuring that system frequency is stable, maintains electric system is realized
Row.
The present invention is from using in purpose, and in efficiency, the viewpoints such as progressive and novelty are illustrated, the practical progress having
Property, oneself meets the function that Patent Law is emphasized and promotes and use important document, and more than the present invention explanation and attached drawing are only of the invention
Preferred embodiment and oneself, the present invention is not limited to this, therefore, it is all constructed with the present invention, device, wait the approximations, thunder such as levy
With, i.e., all according to equivalent replacement made by present patent application range or modification etc., the patent application that should all belong to of the invention is protected
Within the scope of shield.
It should be noted that in the absence of conflict, the feature in embodiment and embodiment in the present invention can phase
Mutually combination.Although present invention has been a degree of descriptions, it will be apparent that, in the item for not departing from the spirit and scope of the present invention
Under part, the appropriate variation of each condition can be carried out.It is appreciated that the present invention is not limited to the embodiments, and it is attributed to right and wants
The range asked comprising the equivalent replacement of each factor.It will be apparent to those skilled in the art that can as described above
Various other corresponding changes and deformation are made in technical solution and design, and all these change and deformation is all answered
Within this is belonged to the protection scope of the claims of the invention.
Claims (10)
1. electric system low-limit frequency calculation method under a kind of high-power missing characterized by comprising
Construction step constructs the frequency response equivalent model of multi-computer system；
It is primary to simplify step, it is unlinked using feedback and its linear method unlinks to frequency response equivalent model, by multimachine system
System feedback control is changed into feedforward control, and calculates the equivalent inertia and original frequency fall off rate of multi-computer system；
Secondary simplified step calculates open-loop gain and the response time of governor model, by unit tune all types of in multi-computer system
Fast device Approximate Equivalent is first order inertial loop, is simplified again to frequency response equivalent model；
Analyzing step utilizes having for Generation Side and load side in conjunction with the equivalent inertia and original frequency fall off rate of multi-computer system
Function balance obtains the frequency response dynamic process expression formula of frequency response equivalent model using analytic method, and approximation obtains transient state frequency
Rate minimum point is as electric system low-limit frequency under high-power missing.
2. electric system low-limit frequency calculation method under high-power missing according to claim 1, which is characterized in that described
It is primary to simplify step, specifically:
It unlinks at feedback and to simulate frequency difference as the input terminal of all kinds of machine unit speed regulating devices of multi-computer system, the feedback of multi-computer system
It is partially converted into all kinds of units under identical frequency difference input and responds the simple linear superposition for obtaining power, multi-computer system by governor
Frequency values are consistent, and after unlinking all kinds of machine unit speed regulating devices inputs frequency difference it is also consistent；
The net inertia constant H of multi-computer systemnetAre as follows:
Wherein, Stotal-VAFor total specified complex power in electric system, m is the generator sum for being linked into electric system, Sn-VA
For the specified complex power of n-th generator, HnFor the inertia constant of n-th generator, 1≤n≤m, n, m are positive integer；
With the net inertia constant H of multi-computer systemnetEquivalent inertia as multi-computer system；
When one timing of power shortage, enabling load end frequency variation is Δ PL, the variable quantity of multi-computer system frequencies omega after being disturbed
The relationship expression of Δ ω and time t are as follows:
Then Δ ω (t) ≈-mΔω·t；
WithOriginal frequency fall off rate as multi-computer system.
3. electric system low-limit frequency calculation method under high-power missing according to claim 2, which is characterized in that described
In secondary simplified step, after simplifying again to frequency response equivalent model, governor response meets:
Wherein, Δ PGiIt (s) is the output power of i-th of dynamo governor, s is plural number, KiFor i-th dynamo governor
Open-loop gain, TiFor the response time of i-th of dynamo governor, 1≤i≤m, i are positive integer.
4. electric system low-limit frequency calculation method under high-power missing according to claim 3, which is characterized in that described
In analyzing step, the frequency response dynamic process expression formula of frequency response equivalent model is obtained by inverse Laplace transformation are as follows:
Because meeting when power-balance:
Wherein, load end frequency variation Δ PLFor power disturbance；
Frequency minimum point time tminMeet:
Then Δ ωmax≈-mΔω·tmin；
According to Δ ωmaxElectric system low-limit frequency under high-power missing is calculated.
5. electric system low-limit frequency calculation method, feature under high-power missing according to claim 1-4
It is, in the secondary simplified step, open-loop gain and the response time of governor model is calculated using least square method.
6. electric system low-limit frequency computing device under a kind of high-power missing characterized by comprising
Module is constructed, for constructing the frequency response equivalent model of multi-computer system；
It is primary to simplify module, it, will be more for being unlinked using feedback and its linear method unlinks to frequency response equivalent model
The control of machine system feedback is changed into feedforward control, and calculates the equivalent inertia and original frequency fall off rate of multi-computer system；
Secondary simplified module, for calculating open-loop gain and the response time of governor model, by machines all types of in multi-computer system
Group governor Approximate Equivalent is first order inertial loop, is simplified again to frequency response equivalent model；
Parsing module utilizes Generation Side and load side for combining the equivalent inertia and original frequency fall off rate of multi-computer system
Active balance, obtain the frequency response dynamic process expression formula of frequency response equivalent model using analytic method, approximation obtains temporary
State frequency minimum point is as electric system low-limit frequency under high-power missing.
7. electric system low-limit frequency computing device under high-power missing according to claim 6, which is characterized in that described
The primary module that simplifies is used for:
It unlinks at feedback and to simulate frequency difference as the input terminal of all kinds of machine unit speed regulating devices of multi-computer system, the feedback of multi-computer system
It is partially converted into all kinds of units under identical frequency difference input and responds the simple linear superposition for obtaining power, multi-computer system by governor
Frequency values are consistent, and after unlinking all kinds of machine unit speed regulating devices inputs frequency difference it is also consistent；
The net inertia constant H of multi-computer systemnetAre as follows:
Wherein, Stotal-VAFor total specified complex power in electric system, m is the generator sum for being linked into electric system, Sn-VA
For the specified complex power of n-th generator, HnFor the inertia constant of n-th generator, 1≤n≤m, n, m are positive integer；
With the net inertia constant H of multi-computer systemnetEquivalent inertia as multi-computer system；
When one timing of power shortage, enabling load end frequency variation is Δ PL, the variable quantity of multi-computer system frequencies omega after being disturbed
The relationship expression of Δ ω and time t are as follows:
Then Δ ω (t) ≈-mΔω·t；
WithOriginal frequency fall off rate as multi-computer system.
8. electric system low-limit frequency computing device under high-power missing according to claim 7, which is characterized in that described
After secondary simplified module again simplifies frequency response equivalent model, governor response meets:
Wherein, Δ PGiIt (s) is the output power of i-th of dynamo governor, s is plural number, KiFor i-th dynamo governor
Open-loop gain, TiFor the response time of i-th of dynamo governor, 1≤i≤m, i are positive integer.
9. electric system low-limit frequency computing device under high-power missing according to claim 8, which is characterized in that described
Parsing module obtains the frequency response dynamic process expression formula of frequency response equivalent model by inverse Laplace transformation are as follows:
Because meeting when power-balance:
Wherein, load end frequency variation Δ PLFor power disturbance；
Frequency minimum point time tminMeet:
Then Δ ωmax≈-mΔω·tmin；
According to Δ ωmaxElectric system low-limit frequency under high-power missing is calculated.
10. according to electric system low-limit frequency computing device, feature under the described in any item high-power missings of claim 6-9
It is, the secondary simplified module calculates open-loop gain and the response time of governor model using least square method.
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