CN105281329B

CN105281329B - A kind of single-phase time sequence of coincidence setting method for improving 2 electro-mechanical force system transient modelling frequency stabilities

Info

Publication number: CN105281329B
Application number: CN201510740422.7A
Authority: CN
Inventors: 孙士云; 陈春敏; 束洪春; 韩军强; 董俊; 唐岚; 杨毅
Original assignee: Kunming University of Science and Technology
Current assignee: Kunming University of Science and Technology
Priority date: 2015-11-04
Filing date: 2015-11-04
Publication date: 2017-09-22
Anticipated expiration: 2035-11-04
Also published as: CN105281329A

Abstract

The present invention relates to a kind of single-phase time sequence of coincidence setting method for improving 2 electro-mechanical force system transient modelling frequency stabilities, belong to power system stability and control technical field.The admittance battle array of each sequence is inverted and obtains the Impedance Matrix of each sequence by the present invention；Port Impedance battle array is tried to achieve using dual-port theory first, and then tries to achieve comprehensive impedance battle array, it is inverted and obtains complex admittance battle array；According to complex admittance battle array modification positive sequence network, so that the positive sequence admittance battle array that is expanded；The equivalent transadmittance between 2 generator nodes is calculated using Ward equivalent methods, thus the generator frequency variation track under two kinds of reclosing time sequences is calculated, realize the quantitative evaluation to frequency variation track to obtain transient frequency stability margin, choose coincidence scheme of the corresponding time sequence of coincidence of transient frequency stability margin the greater for optimization.The present invention makes the analysis of complex fault calculate greatly simplified；Transient frequency stability when 2 machine systems carry out single-phase lock can be effectively improved, is worked well.

Description

A kind of single-phase time sequence of coincidence for improving 2 electro-mechanical force system transient modelling frequency stabilities is adjusted Method

Technical field

The present invention relates to a kind of single-phase time sequence of coincidence setting method for improving 2 electro-mechanical force system transient modelling frequency stabilities, category In power system stability and control technical field.

Background technology

Frequency is an important operating index in power system, is also the pith of power system stability operation.It Reflecting active power that generator sent and load, (including burden with power, the loss in network that power plant is consumed have The burden with power that workload and various electrical equipments are consumed) between dynamic equilibrium relation.In order to meet user's request, The general fluctuation range no more than ± 0.2 Η z of the skew of frequency in power system, when system is not to be strict with, system Frequency can not exceed ± 0.5Hz fluctuation range, so the fluctuation of frequency is to surpass in power system normal work Cross allowed scope.If the fluctuation of frequency is beyond the scope allowed it is necessary to making frequency by corresponding control measure Maintain in allowed limits.

After disturbing, the dynamic process of frequency of each department not only has the distribution of time, and has a distribution in space, Just says different at the time of, the dynamic process of frequency difference of same node or areal；In synchronization, different nodes or The dynamic process of the different regional frequency of person is also different.The amplitude of different regions hunting of frequency is also different.

Transient frequency is generally divided into system-wide transient frequency, regional transient frequency, generator transient frequency and general mother The transient frequency of line.System-wide transient frequency refers to be acted on the total equivalent rotary inertia of system by system imbalance power summation Produced incremental speed changes with time.Regional transient frequency refer to this area's imbalance power summation act on this area be used to Property center total equivalent rotary inertia on produced by incremental speed change with time.Generator node transient frequency is to generate electricity Machine incremental speed changes with time, namely with generator speed directly corresponding frequency.General bus transient frequency be secondly The incremental speed that the space vector of voltage of phase voltage instantaneous value synthesis rotates in phase plane changes with time.

Single-pole reclosing sequential is adjusted, it is therefore an objective to the Secondary Shocks again reduced to system of being tried one's best when coinciding with permanent fault With uneven energy, weaken the adverse effect to power network, improve the transmittability of network.It is single-phase under the stable visual angle of transient frequency Adjusting for reclosing time sequence needs an index, and this index is exactly transient frequency stability margin.When system transient modelling frequency is steady When determining nargin more than 0, system is stable, and numerical value is more big more is conducive to system stable；When system transient modelling frequency stabilization nargin During less than 0, system is unstable, and the smaller stabilization for being more unfavorable for system, passes through the size of transient frequency stability margin value To carry out the best match of single-pole reclosing sequential.

Dual-port is theoretical, Ward equivalent methods are a kind of simplifying methods of network, and it is by the electric power networks of complicated, high-order Letter is simple low order network, carries out such simplification and not only can guarantee that computational accuracy, while computational efficiency can be greatly improved. Patent of the present invention calculates generator frequency versus time curve under two kinds of time sequence of coincidence, and computing system transient frequency is steady Determine nargin and realize the quantitative evaluation that track is changed over time to frequency, selecting system transient frequency margin of safety the greater is corresponding Single-phase time sequence of coincidence is used as optimal coincidence setting program.

The content of the invention

The invention provides a kind of single-phase time sequence of coincidence setting method for improving 2 electro-mechanical force system transient modelling frequency stabilities, Placed an order the optimization problem of timing scheme of coinciding for solving the stable visual angle of transient frequency in 2 electromechanical Force systems.

The technical scheme is that：A kind of single-phase time sequence of coincidence for improving 2 electro-mechanical force system transient modelling frequency stabilities is whole Determine method, when singlephase earth fault occurs for the transmission line of alternation current of 2 electromechanical Force systems, there are two kinds of failures in single-phase coincidence I.e. singlephase earth fault and single-phase wire break failure, form the fault network of dual-port；Symmetrical component method is utilized according to fault type Three sequence sequence nets are obtained, the admittance battle array of each sequence is write according to positive sequence, negative phase-sequence, zero-sequence network row, the admittance battle array of each sequence is inverted and obtains each sequence Impedance Matrix；Port Impedance battle array is tried to achieve using dual-port theory first, and then tries to achieve comprehensive impedance battle array, it is inverted and integrated Admittance battle array；According to complex admittance battle array modification positive sequence network, so that the positive sequence admittance battle array that is expanded；2 are calculated using Ward equivalent methods Equivalent transadmittance between platform generator node, thus calculates the generator frequency variation track under two kinds of reclosing time sequences, Realize the quantitative evaluation to frequency variation track to obtain transient frequency stability margin, choose transient frequency stability margin larger The corresponding time sequence of coincidence of person is the coincidence scheme of optimization.

Methods described is comprised the following steps that：

(1) analog line head end input single-pole reclosing

1) positive sequence, negative phase-sequence, zero sequence admittance battle array are formed

Analog line head end puts into single-pole reclosing, equivalent to the multiple event that there occurs single-phase earthing and single-phase end broken string Barrier, is initially formed positive sequence, negative phase-sequence, zero sequence admittance battle array under the multiple failure, is designated as Y₁、Y₂、Y₀；Wherein, the method for admittance battle array is formed such as Under：The number of nonzero element is equal to the connected earth-free circuitry number of corresponding node in each row off-diagonal element of admittance battle array；Admittance battle array Each diagonal element, i.e., the self-admittance Y of each node_iiEqual to the admittance sum on respective nodes institute's chord road：Admittance The transadmittance Yij of each off-diagonal element of battle array is equal to connect between 2 nodes the negative value of admittance：Y_ij=-y_ij；

In formula, y_ijFor the admittance on institute's chord road between node i and node j；

2) positive sequence, negative phase-sequence, zero sequence impedance battle array are asked for

To positive sequence, negative phase-sequence, zero sequence admittance battle array Y₁、Y₂、Y₀Invert, as shown in formula (1), obtain positive sequence, negative phase-sequence, zero sequence impedance Battle array, is designated as Z₁、Z₂、Z₀；

3) port Impedance is asked for using dual-port theory

1. positive sequence, negative phase-sequence, zero sequence self-impedance and the mutual impedance of port 1 and port 2 are asked for；

If corresponding node serial number is m, n at generation singlephase earth fault, n is 0 node of the earth；Single-phase end disconnection fault Locate corresponding node serial number for p, q；It is that the corresponding port of m, n is denoted as port 1 by node serial number；Node serial number is that p, q are corresponding Port is denoted as port 2；

By step 2) in the three sequence Impedance Matrixes that calculate corresponding element substitute into formula (2), try to achieve port 1 and port 2 Positive sequence, negative phase-sequence, the self-impedance of zero sequence and mutual impedance；

Z₁₁₍₁₎=Z₁₁₍₂₎=Z_mm(1)+Z_nn(1)-2Z_mn(1)

Z₁₂₍₁₎=Z₁₂₍₂₎=Z_mp(1)+Z_nq(1)-Z_mq(1)-Z_np(1)

Z₂₁₍₁₎=Z₂₁₍₂₎=Z_pm(1)+Z_qn(1)-Z_pn(1)-Z_qm(1)

Z₂₂₍₁₎=Z₂₂₍₂₎=Z_pp(1)+Z_qq(1)-2Z_pq(1)

Z₁₁₍₀₎=Z_mm(0)+Z_nn(0)-2Z_mn(0) (2)

Z₁₂₍₀₎=Z_mp(0)+Z_nq(0)-Z_mq(0)-Z_np(0)

Z₂₁₍₀₎=Z_pm(0)+Z_qn(0)-Z_pn(0)-Z_qm(0)

Z₂₂₍₀₎=Z₂₂₍₀₎=Z_pp(0)+Z_qq(0)-2Z_pq(0)

In formula, Z₁₁₍₁₎、Z₂₂₍₁₎The positive sequence self-impedance of port 1 and port 2 is represented respectively；Z₁₂₍₁₎、Z₂₁₍₁₎Port is represented respectively Positive sequence mutual impedance between 1 and port 2；Z₁₁₍₂₎、Z₂₂₍₂₎The negative phase-sequence self-impedance of port 1 and port 2 is represented respectively；Z₁₂₍₂₎、Z₂₁₍₂₎ The negative phase-sequence mutual impedance between port 1 and port 2 is represented respectively；Z₁₁₍₀₎、Z₂₂₍₀₎Represent that the zero sequence of port 1 and port 2 hinders certainly respectively It is anti-；Z₁₂₍₀₎、Z₂₁₍₀₎The zero sequence mutual impedance between port 1 and port 2 is represented respectively；Z_uv(1)(u=m, n, p, q；V=m, n, p, q) Represent Impedance Matrix Z₁In u row v column elements, Z_uv(2)(u=m, n, p, q；V=m, n, p, q) represent Impedance Matrix Z₂In u rows v arrange Element, Z_uv(0)(u=m, n, p, q；V=m, n, p, q) represent Impedance Matrix Z₀In u row v column elements；

2. the port Impedance battle array of the positive sequence, negative phase-sequence, zero sequence of port 1 and port 2 is sought

Obtained each sequence impedance is calculated by formula (2), positive sequence, negative phase-sequence, zero sequence port Impedance battle array is formed, Z is denoted as respectively₍₁₎、 Z₍₂₎、Z₍₀₎, as shown in formula (3)；

4) comprehensive impedance battle array Z is asked for_F

1. obtained each sequence impedance element is calculated according to by formula (2), row write negative phase-sequence, zero sequence port comprehensive impedance battle array Z, such as formula (4) shown in；

2. negative phase-sequence shown in formula (4), zero sequence port comprehensive impedance battle array Z are substituted into formula (5) counter circuit Impedance Matrix Z_L；

In formula,C^TFor C transposition；Z′_st(s=a, b, c；L=a, b, c), during s=l, represent back Road s self-impedance；During s ≠ l, the mutual impedance between loop s and loop l is represented；

Formula (5) is 3. eliminated to the impedance element of the corresponding impedance elements of closed-loop path c, retention loop a and loop b by formula (6) Element, obtains comprehensive impedance battle array Z_F, as shown in formula (7)；

In formula, Z_sl(s=a, b；L=a, b) during s=l, represents to eliminate the self-impedance of loop s behind closed-loop path；During s ≠ l, Represent to eliminate the mutual impedance behind closed-loop path between loop s and loop l；Z′_sl(s=a, b；L=a, b) during s=l, represents loop s Self-impedance；During s ≠ l, the mutual impedance between loop s and loop l is represented；Z′_sc(s=a, b) between expression loop s and loop c Mutual impedance；Z′_cl(l=a b) represents the mutual impedance between loop c and loop l；Z′_ccRepresent loop c self-impedance；

In formula, Z_sl(s=a, b；L=a, b), during s=l, represents to eliminate the self-impedance of loop s behind closed-loop path；During s ≠ l, Represent to eliminate the mutual impedance behind closed-loop path between loop s and loop l；

5) formula (8) is inverted and obtains complex admittance battle array, be denoted as Y_F, as shown in formula (8)

In formula, y_sl(s=a, b；L=a, b), during s=l, represents to eliminate the self-admittance of loop s behind closed-loop path；During s ≠ l, Represent to eliminate the transadmittance behind closed-loop path between loop s and loop l；

6) complex admittance battle array Y is utilized_FIn element modification positive sequence admittance battle array Y₁Middle corresponding element, amending method is shown in formula (9) positive sequence that, is expanded admittance battle array Y_1E

In formula, y '_uv(1) (u=m, n；V=m, n) represents extension positive sequence admittance battle array Y_1EIn u row v column elements；y_uv(1)(u =m, n；V=m, n) represents admittance battle array Y₁In u row v column elements；

y′_uv(1)(u=p, q；V=p, q) represents extension positive sequence admittance battle array Y_1EIn u row v column elements；y_uv(1)(u=p, q；v =p, q) represent admittance battle array Y₁In u row v column elements；

7) according to extension positive sequence admittance battle array Y_1E, the equivalent mutual conductance between 2 generator nodes is calculated using ward equivalent methods Receive, be designated as Y₁₂；Specific method is as follows：

1. the set constituted generator 1 and the corresponding node of generator 2 is denoted as remaining node group in boundary node B, network Into set be denoted as external node E, will extension positive sequence admittance battle array Y_1EMatrix in block form form is write, matrix in block form can be obtained and represented Network equation such as formula (10) shown in；

In formula, Y_BBRepresent the admittance battle array corresponding to all boundary nodes；Y_BERepresent all boundary nodes and all outside segments The corresponding admittance battle array of point, and Y_BEEqual to Y_EBTransposition；Y_EERepresent the admittance battle array corresponding to all external nodes；Represent institute There is the column voltage vector of boundary point；Represent the column voltage vector of all external nodes；Represent the injection of all boundary nodes Electric current；Represent the Injection Current of all external nodes；

2. the matrix in block form in formula (10) is substituted into (11) formula and calculated, obtain boundary admittance battle array

In formula,It is the boundary admittance battle array after equivalence, it includes the tribute of the equivalent branch road produced after external network abbreviation Offer；Therefore after the equivalent transadmittance between the node of generator 1 that retains in 2 machine systems and the node of generator 2 is exactly equivalence Boundary admittance, so there is formula (12) establishment：

In formula, G₁₂For equivalent transadmittance Y₁₂Real part, referred to as conductance, and G₁₂＞ 0；B₁₂For equivalent transadmittance Y₁₂Void Portion, referred to as susceptance, and B₁₂＞ 0；

8) by step 7) the middle equivalent transadmittance Y calculated between obtained generator 1 and generator 2₁₂In substitution formula (13), Local derviation K of the active power to respective generator rotor angle of generator 1 and generator 2 is calculated respectively₁₁、K₂₂；

In formula, P_G1、P_G2The respectively active power of generator 1 and generator 2；δ₁、δ₂Respectively generator 1 and generator 2 generator rotor angle； Represent that the active power of generator 1 and generator 2 exists to the partial derivative of generator's power and angle respectively The numerical value of initial time；E_q1、E_q2The respectively electromotive force of generator 1 and generator 2；δ₀Phase at expression system initial work location Angle；|Y₁₂| represent equivalent transadmittance Y₁₂Amplitude,γ represents equivalent transadmittance Y₁₂Phase angle, γ= arctg(B₁₂/G₁₂), and γ ∈ (0, pi/2)；

9) by step 8) in calculate obtained K₁₁、K₂₂2 machine systems is temporary when the single-phase coincidence of head end is calculated in substitution formula (14) The transient state angular frequency of state angular frequency, generator 1 and generator 2 is denoted as Δ ω respectively₁(t)、Δω₂(t)；

In formula, D₁、D₂The damped coefficient of generator 1 and generator 2 is represented respectively；ΔP_m10、ΔP_m20Generator is represented respectively 1 and generator 2 occur chugging；M₁、M₂Represent the rotary inertia of generator 1,2； ω₀For The rated angular velocity of generator, t is the time；

10) because the relation between angular frequency and frequency meets formula (15), by step 9) in calculate obtained generator 1,2 Angular frequency Δ ω₁(t)、Δω₂(t) formula (16) is substituted into, the transient frequency Δ f of generator 1,2 when calculating head end single-phase coincidence₁ (t)、Δf₂(t)；

The π (15) of f=ω/2

In formula, f is frequency；ω is angular frequency；

(2) analog line end input single-pole reclosing

Analog line end puts into single-pole reclosing, equivalent to the multiple event that there occurs single-phase earthing and single-phase head end broken string Barrier, is initially formed positive sequence, negative phase-sequence, zero sequence admittance battle array under the multiple failure, is designated as Y '₁、Y′₂、Y′₀；

2) by Y '₁、Y′₂、Y′₀Substitution formula (1), positive sequence when obtaining the single-phase coincidence of line end of inverting, negative phase-sequence, zero sequence resistance Anti- battle array, is designated as Z '₁、Z′₂、Z′₀；

3) 3 in repeat step (1)) port Impedance is asked for using dual-port theory, it is designated as Z '₍₁₎、Z′₍₂₎、Z′₍₀₎；

4) 4 in repeat step (1)) comprehensive impedance battle array is asked for, it is designated as Z '_F；

5) 5 in repeat step (1)) complex admittance battle array is obtained, it is denoted as Y '_F；

6) 6 in repeat step (1)) utilize complex admittance battle array Y '_FMiddle element modification positive sequence admittance battle array Y '₁Middle corresponding element, The positive sequence that is expanded admittance battle array Y '_1E；

7) 7 in repeat step (1)) according to extension positive sequence admittance battle array Y '_1E, 2 generators are calculated using ward equivalent methods Equivalent transadmittance between node, is designated as Y '₁₂；

8) 8 in repeat step (1)) local derviation of the active power to respective generator rotor angle of generator 1 and generator 2 is calculated respectively K′₁₁、K′₂₂；

9) 9 in repeat step (1)) the transient state angular frequency difference of generator 1 and generator 2 when calculating the single-phase coincidence in end It is denoted as Δ ω '₁(t)、Δω′₂(t)；

10) 10 in repeat step (1)) the transient frequency Δ f ' of generator 1,2 when calculating the single-phase coincidence in end₁ (t)、Δf′₂(t)；

(3) frequency shift (FS) security quantitative evaluation index

Obtained generator transient frequency is calculated to step (1), (2) using formula (17) and carries out quantitative evaluation, circuit is obtained The transient frequency stability margin η of generator 1,2 during head end single-phase coincidence_G1、η_G2, generator 1,2 during line end single-phase coincidence Transient frequency stability margin η '_G1、η′_G2；

η=[f_ext-(f_cr-kT_cr)] × 100% (17)

In formula, f_crAnd T_crIt is the frequency shift (FS) threshold value of generator and the duration allowed, f respectively_extRefer to transient state mistake The limiting value of generator frequency in journey, k is critical frequency shift duration to be converted into the commutation factor of frequency, η for just or Negative value represents that transient frequency is stable or unstable respectively；

The transient frequency stability margin of each generator in 2 machine systems is obtained, each generator transient frequency stability margin is taken most The small transient frequency stability margin being worth as system；

System transient modelling frequency stabilization nargin during the single-phase coincidence of head end is calculated by formula (18), is denoted as η₁；

η₁=min { η_G1,η_G2} (18)

System transient modelling frequency stabilization nargin during the single-phase coincidence in end is calculated by formula (19), is denoted as η₂；

η₂=min { η '_G1,η′_G2} (19)

(4) draw a conclusion

System transient modelling frequency stabilization nargin η during the single-phase coincidence of alternative route first and end₁、η₂, choose the greater corresponding Single-phase time sequence of coincidence as output optimization time sequence of coincidence scheme；If η₁＞ η₂, then single-phase coincidence is put into by circuit head end first； Conversely, putting into single-phase coincidence first by line end.

The present invention operation principle be：

1. dual-port is theoretical

(1) port Impedance is asked for using dual-port theory

When at F1 and at F2 unbalanced fault occurs for power system simultaneously, accessed simultaneously equivalent at F1 and at F2 The impedance of asymmetrical three-phase, is made up of at failure two parts circuit, and a part is the unsymmetric circuit of faults situation, separately A part is the reflection symmetrical original system of triphase parameter.Due to there is failure at two, one is shown as at each failure in sequence net Individual port, therefore the sequence net of double failure is two-port network, i.e. two-port network.

1. positive sequence, negative phase-sequence, zero sequence self-impedance and the mutual impedance of port 1 and port 2 are asked for.

If corresponding node serial number is m, n at generation singlephase earth fault (n is 0 node of the earth)；Line end is single-phase disconnected Corresponding node serial number is p, q at line.It is that the corresponding port of m, n is denoted as port 1 by node serial number；Node serial number is p, q correspondence Port be denoted as port 2.

Corresponding element in positive sequence, negative phase-sequence, zero sequence impedance battle array is substituted into formula (20), try to achieve port 1 and port 2 positive sequence, Negative phase-sequence, the self-impedance of zero sequence and mutual impedance.

Z₁₁₍₁₎=Z₁₁₍₂₎=Z_mm(1)+Z_nn(1)-2Z_mn(1)

Z₁₂₍₁₎=Z₁₂₍₂₎=Z_mp(1)+Z_nq(1)-Z_mq(1)-Z_np(1)

Z₂₁₍₁₎=Z₂₁₍₂₎=Z_pm(1)+Z_qn(1)-Z_pn(1)-Z_qm(1)

Z₂₂₍₁₎=Z₂₂₍₂₎=Z_pp(1)+Z_qq(1)-2Z_pq(1)

Z₁₁₍₀₎=Z_mm(0)+Z_nn(0)-2Z_mn(0) (20)

Z₁₂₍₀₎=Z_mp(0)+Z_nq(0)-Z_mq(0)-Z_np(0)

Z₂₁₍₀₎=Z_pm(0)+Z_qn(0)-Z_pn(0)-Z_qm(0)

Z₂₂₍₀₎=Z₂₂₍₀₎=Z_pp(0)+Z_qq(0)-2Z_pq(0)

2. the port Impedance battle array of the positive sequence, negative phase-sequence, zero sequence of port 1 and port 2 is sought.

Obtained each sequence impedance is calculated by formula (20), positive sequence, negative phase-sequence, zero sequence port Impedance battle array is formed, Z is denoted as respectively₍₁₎、 Z₍₂₎、Z₍₀₎, as shown in formula (21).

(2) comprehensive impedance battle array is asked for

1. negative phase-sequence, zero sequence port comprehensive impedance battle array Z are write according to two-port network row, as shown in formula (22).

2. negative phase-sequence shown in formula (22), zero sequence port comprehensive impedance battle array Z are substituted into formula (23) counter circuit Impedance Matrix Z_L。

3. formula (23) is eliminated into the corresponding impedance elements of closed-loop path c, retention loop a and loop b impedance by formula (24) Element, obtains comprehensive impedance battle array Z_F, as shown in formula (25).

(3) formula (25) is inverted and obtains complex admittance battle array, be denoted as Y_F, as shown in formula (26).

(4) complex admittance battle array Y is utilized_FIn element modification positive sequence admittance battle array Y₁Middle corresponding element, amending method is shown in formula (27) the admittance battle array that, is expanded Y_1E。

In formula, y '_uv(1)(u=m, n；V=m, n) represents extension positive sequence admittance battle array Y_1EIn u row v column elements；y_uv(1)(u= m,n；V=m, n) represents admittance battle array Y₁In u row v column elements；

y′_uv(1)(u=p, q；V=p, q) represents extension positive sequence admittance battle array Y_1EIn u row v column elements；y_uv(1)(u=p, q；v =p, q) represent admittance battle array Y₁In u row v column elements.

2.Ward equivalent methods

The node of former network is represented with set N.The part referred to as external network that abbreviation falls is intended to, its set of node is represented with E.Protect The node of subnetwork is stayed to be represented with collection G is retained.Then there are G ∩ E=N.The associated section of external network node is neutralized retaining collection Point composition boundary node set, is represented with B.The part of outside segments of getting along well point set association is internal node collection, is represented with I.If will lead Receive short matrix representation network equation by I, B, E gather divide, then can write out the network equation represented with matrix in block form form such as Under：

Eliminate the voltage quantities of external nodeHave

In formula,It is the boundary admittance matrix after equivalence, it includes the equivalent branch road that is produced after external network abbreviation Contribution.

The order of equation time of formula (29) is low compared with the order of formula (28), therefore easily calculated.Due to equivalent boundary admittance square Battle arrayAn addition Item is added relative to original YBB, and addition Item is full battle array under many circumstances, soIt is non- Null element is more than YBB, i.e.,By the sparse part of some lost.WhenDimension is relatively low, i.e., solved when boundary node is less after simplifying Network equation (29) is faster than solving former network equation (28).

3. single-phase time sequence of coincidence is to the Influencing Mechanism of system transient modelling frequency stability

The formation of 3.1 admittance battle array

2 machine systems are as shown in Figure 1 under static load model.2 machine systems are powered through double back transmission line of alternation current to load.When When singlephase earth fault occurs for non-head end any point on circuit, when putting into single-pole reclosing by circuit head end and end respectively, Calculate the change of bus frequency when first closing head end and first closing end.

The changing rule of 2 machine system each internal potential frequency of generator when original machine power is undergone mutation, is not examined in analysis Consider the influence of regulating system and part throttle characteristics, focus on empty to disturbance place and frequency in the research of distribution.For ease of right The comprehensive analysis of various phenomenons, carries out relevant theory deduction first.

If 1^#With 2^#Equivalent transadmittance between machine interior nodes is Y₁₂=G₁₂+jB₁₂, the discussion of 2 machine system equivalent transadmittances, In Fig. 1, if line impedance is Z_L=r_L+jx_L, load impedance represents with constant impedance, i.e. Z_Di=R_Di+jX_DiOr Y_Di=G_Di- jB_Di, i=1,2.Wherein, Z_LFor line impedance, r_LFor line resistance, x_LFor line reactance；Z_DiFor load constant impedance, R_DiFor Load resistance, X_DiFor load reactance；Y_DiFor load constant admittance, G_DiFor load conductance, B_DiFor susceptance.

Set againAnd(wherein, x_diFor the reactance of generator, y_iFor leading for two generator nodes Receive, y_LFor the admittance of circuit.) can obtain 2 machine systems admittance battle array be：

Load bus is eliminated to obtain：In formula

Order

It can obtain：

R₁₂=-r_L(x_d2B_D2+x_d1B_D1+1)+r_L(G_D1G_D2-B_D1B_D2)x_d1x_d2

+x_L(x_d1G_D1+x_d2G_D2)+x_d1x_d2(G_D1+G_D2)+x_d1x_d2x_L(G_D1B_D2+G_D2B_D1)

X₁₂=-(x_d1+x_d2+x_L)-r_L(x_d1x_d2+x_d2G_D2+x_d1x_d2(G_D1B_D2+G_D2B_D1))

-x_d1x_d2(B_D1+B_D2)-x_L(x_d1B_D1+x_d2B_D2)-x_d1x_d2x_L(B_D1B_D2-G_D1G_D2)

General r_LVery little, so there is R₁₂＞ 0, X₁₂＜ 0, therefore G₁₂＞ 0, B₁₂＞ 0.Y₁₂=G₁₂+jB₁₂As madeγ=arctg (B₁₂/G₁₂), γ ∈ (0, pi/2).

The transient frequency of 3.2 systems

When system is uniform damping, i.e. D₁/M₁=D₂/M₂During=σ, the analytic solutions of frequency procedure can be obtained：

In formula,Y₁₂=G₁₂+jB₁₂, wherein, G₁₂It is the real part of admittance, and G₁₂＞ 0；B₁₂It is the imaginary part of admittance, and B₁₂＞ 0.|Y₁₂| represent equivalent transadmittance Y₁₂Amplitude, andγ represents admittance Y₁₂Phase angle, and γ=arctg (B₁₂/G₁₂), then there are γ ∈ (0, pi/2)；Generator The 1 and active power local derviation K respectively to respective generator rotor angle of generator 2₁₁、K₂₂；P_G1、P_G2Generator 1 and generator 2 are represented respectively Have power；δ₁、δ₂The generator rotor angle of generator 1 and generator 2 is represented respectively；δ₀Phase angle at expression system initial work location；D_i、 (i=1,2) represent the damped coefficient of generator；ΔP_mi0(i=1,2) represent the chugging that prime mover occurs；M₁、M₂Represent the rotary inertia of generator；ω₀For generator Rated angular velocity.

4. transient frequency stability margin

One group of two-element list [(f shown in Fig. 2_cr1,T_cr1),(f_cr2,T_cr2),...,(f_crl,T_crl)] it is used to description one The TFDA problems of bus.If for the threshold value f of each frequency_crlLess than power network rated frequency (f_r) two-element list, bus Actual frequency is less than threshold value f_crlDuration be both less than corresponding threshold value T_crl；Simultaneously for each threshold value f_crl Higher than power network rated frequency (f_r) two-element list, bus actual frequency exceed threshold value f_crlDuration it is both less than corresponding Threshold value T_crl, then it is assumed that the transient frequency of the bus is stable.Otherwise, it is believed that the transient frequency of the bus is unstable.Its In, f_cr1,...,f_crlFor one group of given frequency threshold value；T_cr1,...,T_crlFor the given frequency threshold value correspondence duration Threshold value.

The stability margin of transient frequency is calculated according to transient frequency versus time curve, it is typically that transient frequency is stable Nargin is denoted as η_fb, formula (32) is its definition：

η_fb=[f_ext-(f_cr-kT_cr)] × 100% (32)

Wherein f_crAnd T_crIt is the frequency shift (FS) threshold value of generator and the duration allowed, f respectively_extRefer to transient process The limiting value of middle generator frequency, k is the commutation factor for critical frequency shift duration being converted into frequency, η_fbFor just (or It is negative) value represents that transient frequency is stable (or unstable).

The beneficial effects of the invention are as follows：

1st, using dual-port theory solve it is single-phase coincide with permanent fault when port battle array, calculate the analysis of complex fault It is greatly simplified.

2nd, in the equivalent transadmittance between asking for 2 generator nodes, using Ward equivalent methods to extension positive sequence admittance battle array Abbreviation is carried out, network size is not only reduced, and improve computational efficiency.

3rd, the stabilization of general frequency is to be compared by the steady-state value of frequency response with given threshold value, so as to judge Frequency is stable or unstable.The present invention obtains characterizing system transient modelling frequency stability using the quantitative evaluation of transient frequency Quantizating index, so as to realize the preferred of single-phase time sequence of coincidence scheme.

4th, a large amount of simulation results show, patent of the present invention can effectively improve transient frequency when 2 machine systems carry out single-phase lock Stability, works well.

Brief description of the drawings

Fig. 1 is 2 machine system wiring figures；Including 2 generator G₁、G₂With 2 transformer T₁、T₂By transmission line of alternation current Load is powered；E in figure_q1、E_q2Respectively G₁、G₂Electromotive force；P_DA、Q_DARespectively bus A load active power and idle Power；P_DC、Q_DCRespectively bus C load active power and reactive power；P_DD、Q_DDRespectively bus D load active power And reactive power；

Fig. 2 is description TFDA two-element list；In figure, f is frequency；f_rFor power network rated frequency；f_cr1、f_cr2、f_cr3Respectively Different frequency threshold values；T₁、T₂、T₃Respectively frequency threshold value f_cr1、f_cr2、f_cr3Corresponding time gate threshold value；When t/s is Between/second；

Fig. 3 is bus 1-bus D circuit head end single phase ground faults, generator G during head end first single-phase coincidence₁'s Frequency variation curve；In figure, generator frequency curve (Hz) is generator frequency (hertz)；Time (s) is the time (second)；

Fig. 4 is bus 1-bus D circuit head end single phase ground faults, generator G during head end first single-phase coincidence₂'s Frequency variation curve；In figure, generator frequency curve (Hz) is generator frequency (hertz)；Time (s) is the time (second)；

Fig. 5 is bus 1-bus D circuit head end single phase ground faults, generator G during the first single-phase coincidence of end₁'s Frequency variation curve；In figure, generator frequency curve (Hz) is generator frequency (hertz)；Time (s) is the time (second)；

Fig. 6 is bus 1-bus D circuit head end single phase ground faults, generator G during the first single-phase coincidence of end₂'s Frequency variation curve；In figure, generator frequency curve (Hz) is generator frequency (hertz)；Time (s) is the time (second)；

Fig. 7 is bus 2-bus D circuit head end single phase ground faults, generator G during head end first single-phase coincidence₁'s Frequency variation curve；In figure, generator frequency curve (Hz) is generator frequency (hertz)；Time (s) is the time (second)；

Fig. 8 is bus 2-bus D circuit head end single phase ground faults, generator G during head end first single-phase coincidence₂'s Frequency variation curve；In figure, generator frequency curve (Hz) is generator frequency (hertz)；Time (s) is the time (second)；

Fig. 9 is bus 2-bus D circuit head end single phase ground faults, generator G during the first single-phase coincidence of end₁'s Frequency variation curve；In figure, generator frequency curve (Hz) is generator frequency (hertz)；Time (s) is the time (second)；

Figure 10 is bus 2-bus D circuit head end single phase ground faults, generator G during the first single-phase coincidence of end₂'s Frequency variation curve；In figure, generator frequency curve (Hz) is generator frequency (hertz)；Time (s) is the time (second).

Embodiment

Embodiment 1：As Figure 1-10 shows, a kind of single-phase time sequence of coincidence for improving 2 electro-mechanical force system transient modelling frequency stabilities , when singlephase earth fault occurs for the transmission line of alternation current of 2 electromechanical Force systems, there are two kinds of events in single-phase coincidence in setting method Barrier is singlephase earth fault and single-phase wire break failure, forms the fault network of dual-port；Symmetrical components are utilized according to fault type Method obtains three sequence sequence nets, and the admittance battle array of each sequence is write according to positive sequence, negative phase-sequence, zero-sequence network row, and the admittance battle array of each sequence is inverted and obtains each The Impedance Matrix of sequence；Port Impedance battle array is tried to achieve using dual-port theory first, and then tries to achieve comprehensive impedance battle array, it is inverted and obtains comprehensive Close admittance battle array；According to complex admittance battle array modification positive sequence network, so that the positive sequence admittance battle array that is expanded；Calculated using Ward equivalent methods Equivalent transadmittance between 2 generator nodes, thus calculates the generator frequency variation track under two kinds of reclosing time sequences, Realize the quantitative evaluation to frequency variation track to obtain transient frequency stability margin, choose transient frequency stability margin larger The corresponding time sequence of coincidence of person is the coincidence scheme of optimization.

Methods described is comprised the following steps that：

(1) analog line head end input single-pole reclosing

Analog line head end puts into single-pole reclosing, equivalent to the multiple event that there occurs single-phase earthing and single-phase end broken string Barrier, is initially formed positive sequence, negative phase-sequence, zero sequence admittance battle array under the multiple failure, is designated as Y₁、Y₂、Y₀；Wherein, the method for admittance battle array is formed such as Under：The number of nonzero element is equal to the connected earth-free circuitry number of corresponding node in each row off-diagonal element of admittance battle array；Admittance battle array Each diagonal element, i.e., the self-admittance Y of each node_iiEqual to the admittance sum on respective nodes institute's chord road：Admittance The transadmittance Y of each off-diagonal element of battle array_ijIt is equal to connect between 2 nodes the negative value of admittance：Y_ij=-y_ij；

3) port Impedance is asked for using dual-port theory

Z₁₁₍₁₎=Z₁₁₍₂₎=Z_mm(1)+Z_nn(1)-2Z_mn(1)

Z₁₂₍₁₎=Z₁₂₍₂₎=Z_mp(1)+Z_nq(1)-Z_mq(1)-Z_np(1)

Z₂₁₍₁₎=Z₂₁₍₂₎=Z_pm(1)+Z_qn(1)-Z_pn(1)-Z_qm(1)

Z₂₂₍₁₎=Z₂₂₍₂₎=Z_pp(1)+Z_qq(1)-2Z_pq(1)

Z₁₁₍₀₎=Z_mm(0)+Z_nn(0)-2Z_mn(0) (2)

Z₁₂₍₀₎=Z_mp(0)+Z_nq(0)-Z_mq(0)-Z_np(0)

Z₂₁₍₀₎=Z_pm(0)+Z_qn(0)-Z_pn(0)-Z_qm(0)

Z₂₂₍₀₎=Z₂₂₍₀₎=Z_pp(0)+Z_qq(0)-2Z_pq(0)

4) comprehensive impedance battle array Z is asked for_F

In formula, y '_uv(1)(u=m, n；V=m, n) represents extension positive sequence admittance battle array Y_1EIn u row v column elements；

y_uv(1)(u=m, n；V=m, n) represents admittance battle array Y₁In u row v column elements；

In formula, G₁₂For equivalent transadmittance Y12 real part, referred to as conductance, and G₁₂＞ 0；B₁₂For equivalent transadmittance Y₁₂Void Portion, referred to as susceptance, and B₁₂＞ 0；

In formula, P_G1、P_G2The respectively active power of generator 1 and generator 2；δ₁、δ₂Respectively generator 1 and generator 2 generator rotor angle； Partial derivative of the active power to generator's power and angle of generator 1 and generator 2 is represented respectively In the numerical value of initial time；E_q1、E_q2The respectively electromotive force of generator 1 and generator 2；δ₀At expression system initial work location Phase angle；|Y₁₂| represent equivalent transadmittance Y₁₂Amplitude,γ represents equivalent transadmittance Y₁₂Phase angle, γ =arctg (B₁₂/G₁₂), and γ ∈ (0, pi/2)；

The π (15) of f=ω/2

In formula, f is frequency；ω is angular frequency；

(2) analog line end input single-pole reclosing

(3) frequency shift (FS) security quantitative evaluation index

η=[f_ext-(f_cr-kT_cr)] × 100% (17)

η₁=min { η_G1,η_G2} (18)

η₂=min { η '_G1,η′_G2} (19)

(4) draw a conclusion

Embodiment 2：As Figure 1-10 shows, a kind of single-phase time sequence of coincidence for improving 2 electro-mechanical force system transient modelling frequency stabilities , when singlephase earth fault occurs for the transmission line of alternation current of 2 electromechanical Force systems, there are two kinds of events in single-phase coincidence in setting method Barrier is singlephase earth fault and single-phase wire break failure, forms the fault network of dual-port；Symmetrical components are utilized according to fault type Method obtains three sequence sequence nets, and the admittance battle array of each sequence is write according to positive sequence, negative phase-sequence, zero-sequence network row, and the admittance battle array of each sequence is inverted and obtains each The Impedance Matrix of sequence；Port Impedance battle array is tried to achieve using dual-port theory first, and then tries to achieve comprehensive impedance battle array, it is inverted and obtains comprehensive Close admittance battle array；According to complex admittance battle array modification positive sequence network, so that the positive sequence admittance battle array that is expanded；Calculated using Ward equivalent methods Equivalent transadmittance between 2 generator nodes, thus calculates the generator frequency variation track under two kinds of reclosing time sequences, Realize the quantitative evaluation to frequency variation track to obtain transient frequency stability margin, choose transient frequency stability margin larger The corresponding time sequence of coincidence of person is the coincidence scheme of optimization.

Embodiment 3：As Figure 1-10 shows,

By taking 2 machine systems shown in Fig. 1 as an example, 8 buses, the node parameter such as table of each generator and bus are had in system Shown in 1, the voltage class of generator 1 is 18.0kV, and the voltage class of generator 1 is 13.8kV, and busbar voltage grade is 230kV.Line The circuit per unit value parameter such as resistance, reactance and the admittance on road is as shown in table 2.8 line voltage distribution grade is 230kV.Transformer The parameter such as resistance, reactance and no-load voltage ratio as shown in table 3, the inertia time constant of generator, the reactance of d-axis transient state, quadrature axis transient state electricity The parameter such as anti-is as shown in table 4.The power reference value for the parameter per unit value being related in table 2- tables 4 takes 100MVA.

A phase singlephase earth faults occur for 2 machine system busbar 1-bus D circuit head ends 0s shown in Fig. 1, and 0.1s circuit A phases are first End tripping operation, 0.2s circuit A phases end tripping operation, 1s circuit A phases head end is overlapped, the tripping operation of 1.2s faulty line first and ends three-phase.Formed Positive sequence, negative phase-sequence, zero sequence admittance battle array when faulty line A phases head end when 1s is overlapped, end is broken, lead to positive sequence, negative phase-sequence, zero sequence Battle array of receiving is inverted, and obtains positive sequence, negative phase-sequence, zero sequence impedance battle array, and positive sequence, negative phase-sequence, the resistance of zero sequence port are asked for using two-port network theory Anti- battle array, is eliminated behind closed-loop path, obtains comprehensive impedance battle array, and comprehensive impedance battle array is inverted, and is obtained complex admittance battle array, is utilized WARD etc. Value method, eliminates after the external node except generator 1 and generator 2, obtains the equivalent transadmittance between generator 1 and generator 2, The transient state angular frequency that formula (14) tries to achieve generator 1 and generator 2 when bus 1-bus D circuit A phases head end is overlapped is substituted into, Transformation relation according to formula (15) between angular frequency and frequency, obtains sending out when bus 1-bus D circuit A phases head end is overlapped The transient frequency of motor 1 and generator 2.

A phase singlephase earth faults, the tripping operation of 0.1s circuit A phases head end, 0.2s lines occur for bus 1-bus D circuit head ends 0s Road A phases end is tripped, and 1s circuit A phases end is overlapped, the tripping operation of 1.2s faulty line first and ends three-phase.Faulty line is formed in 1s When A phases end overlap, head end broken string when positive sequence, negative phase-sequence, zero sequence admittance battle array, to positive sequence, negative phase-sequence, zero sequence admittance battle array invert, obtain To positive sequence, negative phase-sequence, zero sequence impedance battle array, positive sequence, negative phase-sequence, zero sequence port Impedance battle array are asked for using two-port network theory, cancellation is closed Close behind loop, obtain comprehensive impedance battle array, comprehensive impedance battle array is inverted, obtain complex admittance battle array, using WARD equivalent methods, cancellation is removed After the external node of generator 1 and generator 2, the equivalent transadmittance between generator 1 and generator 2 is obtained, formula is substituted into (14) the transient state angular frequency of generator 1 and generator 2 when bus 1-bus D circuit A phases end is overlapped is tried to achieve, according to formula (15) Transformation relation between shown angular frequency and frequency, obtains generator 1 and generating when bus 1-bus D circuit A phases end is overlapped The transient frequency of machine 2.

The transient frequency change curve of generator 1 and generator 2 is carried out when being overlapped to bus 1-bus D circuit A phases head end Quantitative evaluation (as shown in Figure 3,4), chooses generator 1 and the transient frequency stability margin smaller 74.12% of generator 2 as first The transient frequency stability margin of system, is shown in table 5 when end is overlapped.Generator 1 when being overlapped to bus 1-bus D circuit A phases end Quantitative evaluation (as shown in Figure 5,6) is carried out with the transient frequency change curve of generator 2, generator 1 and the transient state of generator 2 is chosen The transient frequency stability margin of system, is shown in table 5 when frequency stabilization nargin smaller 78.44% overlaps as end.Bus 1- Bus D circuit A phase head end failures, the transient frequency stability margin of system, chooses the greater when contrast first and end is overlapped 78.44% corresponding end overlaps the time sequence of coincidence scheme as optimization, is shown in table 6.

Embodiment 4：As Figure 1-10 shows,

A phase singlephase earth faults occur for 2 machine system busbar 2-bus D circuit head ends 0s shown in Fig. 1, and 0.1s circuit A phases are first End tripping operation, 0.2s circuit A phases end tripping operation, 1s circuit A phases head end is overlapped, the tripping operation of 1.2s faulty line first and ends three-phase.Formed Positive sequence, negative phase-sequence, zero sequence admittance battle array when faulty line A phases head end when 1s is overlapped, end is broken, lead to positive sequence, negative phase-sequence, zero sequence Battle array of receiving is inverted, and obtains positive sequence, negative phase-sequence, zero sequence impedance battle array, and positive sequence, negative phase-sequence, the resistance of zero sequence port are asked for using two-port network theory Anti- battle array, is eliminated behind closed-loop path, obtains comprehensive impedance battle array, and comprehensive impedance battle array is inverted, and is obtained complex admittance battle array, is utilized WARD etc. Value method, eliminates after the external node except generator 1 and generator 2, obtains the equivalent transadmittance between generator 1 and generator 2, The transient state angular frequency that formula (14) tries to achieve generator 1 and generator 2 when bus 2-bus D circuit A phases head end is overlapped is substituted into, Transformation relation according to formula (15) between angular frequency and frequency, obtains sending out when bus 2-bus D circuit A phases head end is overlapped The transient frequency of motor 1 and generator 2.

A phase singlephase earth faults, the tripping operation of 0.1s circuit A phases head end, 0.2s lines occur for bus 2-bus D circuit head ends 0s Road A phases end is tripped, and 1s circuit A phases end is overlapped, the tripping operation of 1.2s faulty line first and ends three-phase.Faulty line is formed in 1s When A phases end overlap, head end broken string when positive sequence, negative phase-sequence, zero sequence admittance battle array, to positive sequence, negative phase-sequence, zero sequence admittance battle array invert, obtain To positive sequence, negative phase-sequence, zero sequence impedance battle array, positive sequence, negative phase-sequence, zero sequence port Impedance battle array are asked for using two-port network theory, cancellation is closed Close behind loop, obtain comprehensive impedance battle array, comprehensive impedance battle array is inverted, obtain complex admittance battle array, using WARD equivalent methods, cancellation is removed After the external node of generator 1 and generator 2, the equivalent transadmittance between generator 1 and generator 2 is obtained, formula is substituted into (14) the transient state angular frequency of generator 1 and generator 2 when bus 2-bus D circuit A phases end is overlapped is tried to achieve, according to formula (15) Transformation relation between shown angular frequency and frequency, obtains generator 1 and generating when bus 2-bus D circuit A phases end is overlapped The transient frequency of machine 2.

The transient frequency change curve of generator 1 and generator 2 is carried out when being overlapped to bus 2-bus D circuit A phases head end Quantitative evaluation (as shown in Figure 7,8), chooses generator 1 and the transient frequency stability margin smaller 89.01% of generator 2 as first The transient frequency stability margin of system, is shown in table 5 when end is overlapped.Generator 1 when being overlapped to bus 2-bus D circuit A phases end Quantitative evaluation (as shown in Fig. 9,10) is carried out with the transient frequency change curve of generator 2, generator 1 is chosen and generator 2 is temporary The transient frequency stability margin of system, is shown in table 5 when state frequency stabilization nargin smaller 69.73% overlaps as end.Bus 2-bus D circuit A phase head end failures, the transient frequency stability margin of system, chooses the greater when contrast first and end is overlapped 89.01% corresponding head end overlaps the time sequence of coincidence scheme as optimization, is shown in table 6.

For in above-described embodiment, table 1- tables 6 are as follows：

The machine system node parameter of table 12

The machine system line per unit value parameter of table 22

Note：Power reference value is 100MWA

The machine system transformer parameter of table 32

Note：Power reference value is 100MWA

The machine system generator parameter of table 42

Note：Power reference value is 100MWA

In table 4, T_jFor the inertia time constant of generator, unit is s；x′_dFor d-axis transient state reactance；x′_qFor quadrature axis transient state Reactance；x_dFor the unsaturated synchronous reactance of d-axis；x_qFor the unsaturated synchronous reactance of quadrature axis；T′_d0For d-axis transient state open circuit time constant； T′_q0For quadrature axis transient state open circuit time constant；x_LFor stator leakage reactance；x″_dFor d axle subtranient reactances；x″_qFor q axle subtranient reactances； T″_d0For d axle time time constants；T″_q0For q axle time time constants.

When the transmission line of alternation current single phase ground fault failure of 2 machine systems, generator 1 and generator 2 are in difference The transient frequency stability margin of system is shown in table 5 under single-phase time sequence of coincidence.Choose the corresponding single-phase time sequence of coincidence of nargin the greater As the coincidence scheme of optimization, the single-phase time sequence of coincidence scheme of raising transient frequency stability as shown in table 6 is obtained.

The transient frequency stability margin of table 5

Table 6 optimizes time sequence of coincidence scheme

Above in conjunction with accompanying drawing to the present invention embodiment be explained in detail, but the present invention be not limited to it is above-mentioned Embodiment, can also be before present inventive concept not be departed from the knowledge that those of ordinary skill in the art possess Put and make a variety of changes.

Claims

1. a kind of single-phase time sequence of coincidence setting method for improving 2 electro-mechanical force system transient modelling frequency stabilities, it is characterised in that：When 2 In the presence of two kinds of failures it is single-phase earthing in single-phase coincidence when singlephase earth fault occurs for the transmission line of alternation current of electromechanical Force system Failure and single-phase wire break failure, form the fault network of dual-port；Three sequence sequences are obtained using symmetrical component method according to fault type Net, the admittance battle array of each sequence is write according to positive sequence, negative phase-sequence, zero-sequence network row, and the admittance battle array of each sequence is inverted and obtains the Impedance Matrix of each sequence；Adopt Try to achieve port Impedance battle array first with dual-port theory, and then try to achieve comprehensive impedance battle array, it is inverted and obtains complex admittance battle array；According to Complex admittance battle array modification positive sequence network, so that the positive sequence admittance battle array that is expanded；2 generator nodes are calculated using Ward equivalent methods Between equivalent transadmittance, thus calculate the generator frequency variation track under two kinds of reclosing time sequences, realize and frequency is become Change the quantitative evaluation of track to obtain transient frequency stability margin, choose the corresponding coincidence of transient frequency stability margin the greater Sequential is the coincidence scheme of optimization.

2. the single-phase time sequence of coincidence setting method according to claim 1 for improving 2 electro-mechanical force system transient modelling frequency stabilities, It is characterized in that：Methods described is comprised the following steps that：

(1) analog line head end input single-pole reclosing

Analog line head end puts into single-pole reclosing, first equivalent to the multiple failure that there occurs single-phase earthing and single-phase end broken string Positive sequence, negative phase-sequence, zero sequence admittance battle array under the multiple failure are initially formed, Y is designated as₁、Y₂、Y₀；Wherein, the method for forming admittance battle array is as follows：Lead The number of nonzero element is equal to the connected earth-free circuitry number of corresponding node in each row off-diagonal element of battle array of receiving；Admittance battle array is each diagonal Element, i.e., the self-admittance Y of each node_iiEqual to the admittance sum on respective nodes institute's chord road：Admittance battle array is each non- The transadmittance Y of diagonal element_ijIt is equal to connect between 2 nodes the negative value of admittance：Y_ij=-y_ij；

To positive sequence, negative phase-sequence, zero sequence admittance battle array Y₁、Y₂、Y₀Invert, as shown in formula (1), obtain positive sequence, negative phase-sequence, zero sequence impedance battle array, note For Z₁、Z₂、Z₀；

3) port Impedance is asked for using dual-port theory

If corresponding node serial number is m, n at generation singlephase earth fault, n is 0 node of the earth；At single-phase end disconnection fault pair The node serial number answered is p, q；It is that the corresponding port of m, n is denoted as port 1 by node serial number；Node serial number is the corresponding port of p, q It is denoted as port 2；

In formula, Z₁₁₍₁₎、Z₂₂₍₁₎The positive sequence self-impedance of port 1 and port 2 is represented respectively；Z₁₂₍₁₎、Z₂₁₍₁₎The He of port 1 is represented respectively Positive sequence mutual impedance between port 2；Z₁₁₍₂₎、Z₂₂₍₂₎The negative phase-sequence self-impedance of port 1 and port 2 is represented respectively；Z₁₂₍₂₎、Z₂₁₍₂₎Point Negative phase-sequence mutual impedance that Biao Shi be between port 1 and port 2；Z₁₁₍₀₎、Z₂₂₍₀₎Represent that the zero sequence of port 1 and port 2 hinders certainly respectively It is anti-；Z₁₂₍₀₎、Z₂₁₍₀₎The zero sequence mutual impedance between port 1 and port 2 is represented respectively；Z_uv(1)(u=m, n, p, q；V=m, n, p, q) Represent Impedance Matrix Z₁In u row v column elements, Z_uv(0)(u=m, n, p, q；V=m, n, p, q) represent Impedance Matrix Z₀In u rows v arrange Element；

Obtained each sequence impedance is calculated by formula (2), positive sequence, negative phase-sequence, zero sequence port Impedance battle array is formed, Z is denoted as respectively₍₁₎、Z₍₂₎、 Z₍₀₎, as shown in formula (3)；

4) comprehensive impedance battle array Z is asked for_F

1. obtained each sequence impedance element is calculated according to by formula (2), row write negative phase-sequence, zero sequence port comprehensive impedance battle array Z, such as formula (4) It is shown；

In formula,C^TFor C transposition；Z′_sl(s=a, b, c；L=a, b, c), during s=l, represent loop s's Self-impedance；During s ≠ l, the mutual impedance between loop s and loop l is represented；

Formula (5) is 3. eliminated to the impedance element of the corresponding impedance elements of closed-loop path c, retention loop a and loop b by formula (6), obtained To comprehensive impedance battle array Z_F, as shown in formula (7)；

In formula, Z_sl(s=a, b；L=a, b) during s=l, represents to eliminate the self-impedance of loop s behind closed-loop path；During s ≠ l, represent Eliminate the mutual impedance between loop s and loop l behind closed-loop path；Z′_sl(s=a, b；L=a, b) during s=l, represent loop s from Impedance；During s ≠ l, the mutual impedance between loop s and loop l is represented；Z′_sc(s=a, it is b) mutual between expression loop s and loop c Impedance；Z′_cl(l=a b) represents the mutual impedance between loop c and loop l；Z′_ccRepresent loop c self-impedance；

In formula, Z_sl(s=a, b；L=a, b), during s=l, represents to eliminate the self-impedance of loop s behind closed-loop path；During s ≠ l, represent Eliminate the mutual impedance between loop s and loop l behind closed-loop path；

5) formula (7) is inverted and obtains complex admittance battle array, be denoted as Y_F, as shown in formula (8)

In formula, y_sl(s=a, b；L=a, b), during s=l, represents to eliminate the self-admittance of loop s behind closed-loop path；During s ≠ l, represent Eliminate the transadmittance between loop s and loop l behind closed-loop path；

6) complex admittance battle array Y is utilized_FIn element modification positive sequence admittance battle array Y₁Middle corresponding element, amending method is shown in formula (9), obtains To extension positive sequence admittance battle array Y_1E

In formula, y '_uv(1)(u=m, n；V=m, n) represents extension positive sequence admittance battle array Y_1EIn u row v column elements；y_uv(1)(u=m, n； V=m, n) represents admittance battle array Y₁In u row v column elements；

y′_uv(1)(u=p, q；V=p, q) represents extension positive sequence admittance battle array Y_1EIn u row v column elements；y_uv(1)(u=p, q；V=p, Q) admittance battle array Y is represented₁In u row v column elements；

7) according to extension positive sequence admittance battle array Y_1E, the equivalent transadmittance between 2 generator nodes, note are calculated using ward equivalent methods For Y₁₂；Specific method is as follows：

1. the set constituted generator 1 and the corresponding node of generator 2 is denoted as what remaining node in boundary node B, network was constituted Set is denoted as external node E, by extension positive sequence admittance battle array Y_1EMatrix in block form form is write, the net that matrix in block form is represented can be obtained Shown in network equation such as formula (10)；

In formula, Y_BBRepresent the admittance battle array corresponding to all boundary nodes；Y_BERepresent all boundary nodes and all external nodes institute Corresponding admittance battle array, and Y_BEEqual to Y_EBTransposition；Y_EERepresent the admittance battle array corresponding to all external nodes；Represent all sides The column voltage vector of boundary's point；Represent the column voltage vector of all external nodes；Represent the injection electricity of all boundary nodes Stream；Represent the Injection Current of all external nodes；

In formula,It is the boundary admittance battle array after equivalence, it includes the contribution of the equivalent branch road produced after external network abbreviation； Therefore the border after the equivalent transadmittance between the node of generator 1 that retains in 2 machine systems and the node of generator 2 is exactly equivalence Admittance, so there is formula (12) establishment：

In formula, G₁₂For equivalent transadmittance Y₁₂Real part, referred to as conductance, and G₁₂>0；B₁₂For equivalent transadmittance Y₁₂Imaginary part, be referred to as Susceptance, and B₁₂>0；

8) by step 7) the middle equivalent transadmittance Y calculated between obtained generator 1 and generator 2₁₂In substitution formula (13), respectively Local derviation K of the active power of calculating generator 1 and generator 2 to respective generator rotor angle₁₁、K₂₂；

In formula, P_G1、P_G2The respectively active power of generator 1 and generator 2；δ₁、δ₂Respectively generator 1 and generator 2 Generator rotor angle；Represent the active power of generator 1 and generator 2 to the partial derivative of generator's power and angle first respectively The numerical value at moment beginning；E_q1、E_q2The respectively electromotive force of generator 1 and generator 2；δ₀Phase at expression system initial work location Angle；|Y₁₂| represent equivalent transadmittance Y₁₂Amplitude,γ represents equivalent transadmittance Y₁₂Phase angle, γ= arctg(B₁₂/G₁₂), and γ ∈ (0, pi/2)；

9) by step 8) in calculate obtained K₁₁、K₂₂The transient state angle of 2 machine systems when the single-phase coincidence of head end is calculated in substitution formula (14) The transient state angular frequency of frequency, generator 1 and generator 2 is denoted as Δ ω respectively₁(t)、Δω₂(t)；

In formula, D₁、D₂The damped coefficient of generator 1 and generator 2 is represented respectively；ΔP_m10、ΔP_m20The He of generator 1 is represented respectively The chugging that generator 2 occurs；M₁、M₂Represent the rotary inertia of generator 1,2；ω₀For The rated angular velocity of generator, t is the time；

10) because the relation between angular frequency and frequency meets formula (15), by step 9) the middle angle for calculating obtained generator 1,2 Frequency Δ ω₁(t)、Δω₂(t) formula (16) is substituted into, the transient frequency Δ f of generator 1,2 when calculating head end single-phase coincidence₁(t)、 Δf₂(t)；

The π (15) of f=ω/2

In formula, f is frequency；ω is angular frequency；

(2) analog line end input single-pole reclosing

Analog line end puts into single-pole reclosing, first equivalent to the multiple failure that there occurs single-phase earthing and single-phase head end broken string Positive sequence, negative phase-sequence, zero sequence admittance battle array under the multiple failure are initially formed, Y ' is designated as₁、Y′₂、Y′₀；

2) by Y '₁、Y′₂、Y′₀Substitution formula (1), positive sequence, negative phase-sequence, the zero sequence impedance battle array inverted when obtaining the single-phase coincidence of line end, It is designated as Z '₁、Z′₂、Z′₀；

6) 6 in repeat step (1)) utilize complex admittance battle array Y '_FMiddle element modification positive sequence admittance battle array Y '₁Middle corresponding element, is obtained To extension positive sequence admittance battle array Y '_1E；

7) 7 in repeat step (1)) according to extension positive sequence admittance battle array Y '_1E, 2 generator nodes are calculated using ward equivalent methods Between equivalent transadmittance, be designated as Y '₁₂；

8) 8 in repeat step (1)) local derviation K ' of the active power to respective generator rotor angle of generator 1 and generator 2 is calculated respectively₁₁、 K′₂₂；

9) 9 in repeat step (1)) the transient state angular frequency of generator 1 and generator 2 is denoted as respectively when calculating the single-phase coincidence in end Δω′₁(t)、Δω′₂(t)；

10) 10 in repeat step (1)) the transient frequency Δ f ' of generator 1,2 when calculating the single-phase coincidence in end₁(t)、Δf′₂ (t)；

(3) frequency shift (FS) security quantitative evaluation index

Obtained generator transient frequency is calculated to step (1), (2) using formula (17) and carries out quantitative evaluation, circuit head end is obtained The transient frequency stability margin η of generator 1,2 during single-phase coincidence_G1、η_G2, the transient state of generator 1,2 during line end single-phase coincidence Frequency stabilization nargin η '_G1、η′_G2；

η=[f_ext-(f_cr-kT_cr)] × 100% (17)

In formula, f_crAnd T_crIt is the frequency shift (FS) threshold value of generator and the duration allowed, f respectively_extRefer in transient process and send out The limiting value of electric machine frequency, k is the commutation factor for critical frequency shift duration being converted into frequency, and η is positive or negative value point Biao Shi not transient frequency stabilization or unstable；

The transient frequency stability margin of each generator in 2 machine systems is obtained, each generator transient frequency stability margin minimum value is taken It is used as the transient frequency stability margin of system；

η₁=min { η_G1, η_G2} (18)

η₂=min { η '_G1,η′_G2} (19)

(4) draw a conclusion

System transient modelling frequency stabilization nargin η during the single-phase coincidence of alternative route first and end₁、η₂, choose the greater corresponding single-phase Time sequence of coincidence as output optimization time sequence of coincidence scheme；If η₁>η₂, then single-phase coincidence is put into by circuit head end first；Conversely, Put into single-phase coincidence first by line end.