CN102427224A - Reclosing time on-line capturing method of power transmission line - Google Patents

Abstract

The invention discloses a reclosing time on-line capturing method of a power transmission line. The reclosing time on-line capturing method is characterized by comprising the following steps of: constructing a transient state energy function based on a power system structure keeping model, establishing a branch transient state potential energy function, analyzing transient characteristics of the power transmission line based on branch transient state potential energy, setting reclosing time and the like. According to the reclosing time on-line capturing method of the power transmission line, disclosed by the invention, the optimal reclosing time can be set exactly in real time by fully and effectively utilizing the measured branch information so that the transient state stability of a system is improved; in addition, the invention has the advantages of simple calculation, easiness for implementation, high application value and the like.

Description

The transmission line reclosing is online method for catching constantly

Technical field

The present invention is a kind of transmission line reclosing online method for catching constantly, belongs to power system stability and control technology field.

Background technology

Most of faults are transient fault in the electric power system, and therefore in extra-high voltage transmission, adopting auto recloser is one of important measures that improve the power system transient stability quality.But how on the basis of time reclosing device minimum pause, optimize reclosure time receive publicity always with the research that improves power system transient stability property effectively.Showing that from available research achievements optimum reclosing exists constantly, promptly is not the vibration that faster coincidence helps suppressing to overlap the follow-up pendulum of back system more.Therefore, in recent years, work about electric power person's optimum reclosure time of how adjusting during to system's generation transient fault has carried out deep exploration.But most at present research still is confined to the analysis of adjusting of off-line, and method is complicated, is difficult to adapt to the operational mode of large scale system and the variation of failure mode.

Along with the progress of microcomputer type Protection Technology and global position system GPS in application on power system, realize that the auto recloser that automatic adaptive system operation and malfunction change created condition.But how can effectively utilize the information that the measures optimum reclosure time of accurately adjusting in real time and still need do further research with the transient stability level that improves system.

Summary of the invention

The objective of the invention is fully and effectively utilize the branch road information that measures and accurately adjust optimum reclosure time in real time to improve the transient stability level of system, calculate simple, be easy to realize and transmission line reclosing that using value is high online method for catching constantly.

A kind of transmission line reclosing is online method for catching constantly, it is characterized in that it comprises the steps:

The first step: the structure that keeps the transient energy function of model based on NETWORK STRUCTURE PRESERVING POWER SYSTEM

$V=\frac{1}{2}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{M}_i{\mathrm{\&omega;}}_i^2+\underset{k=1}{\overset{l}{\mathrm{\&Sigma;}}}{\&Integral;}_{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="HDA0000101138480000012.png,HDA0000101138480000022.png"\; state="\{\{state\}\}">k</figure-callout>}}^0}^{{\mathrm{\&sigma;}}_k}[P_k\left(u\right)-P_k^s]\mathrm{du}+\underset{k=1}{\overset{l}{\mathrm{\&Sigma;}}}{\&Integral;}_{{\mathrm{\&sigma;}}_k^s}^{{\mathrm{\&sigma;}}_k^0}[P_k\left(u\right)-P_k^s]\mathrm{du}---\left(1\right)$

Wherein: V is the gross energy that NETWORK STRUCTURE PRESERVING POWER SYSTEM keeps model,

M _iBe the inertia time constant of i platform generator, m is generating board number,

ω _iBe the angular speed of i platform generator,

is the reference point of i bar branch road phase angle; L is a way

σ _iBe i bar branch road phase angle,

is the active power of branch road k with respect to stable equilibrium point

P _kActive power for branch road k;

Second step: the foundation of branch road transient potential energy function

$V_{\mathrm{PEk}}\left(t\right)={\&Integral;}_{t_0}^t{\mathrm{\&omega;}}_N[P_k\left(u\right)-P_k^s]{\mathrm{\&omega;}}_k^{\%}\left(u\right)\mathrm{du}---\left(2\right)$

Wherein: V _PEKBe the branch road potential energy of branch road k,

ω _NBe rated angular velocity,

is two ends bus angular frequency poor of branch road k;

The 3rd step: the transmission line transient characterisitics based on branch road potential energy are analyzed

If certain a pair of in the network returns the A-wire generation instantaneity short trouble in first and second power transmission lines, t _cFault, t are removed in circuit both sides switch motion constantly _RecThe circuit of automatic reclosing action constantly overlaps, and in this failure sequence process, the variation of the reactance between node i, j causes active power therebetween to change, thereby influences the level of sharing of the transient potential energy between node i, j,

For between node i, j, its transient potential energy can be described as:

$V_{\mathrm{PE}(i-j)}={\&Integral;}_{{\mathrm{\&sigma;}}_{a(i-j)}}^{{\mathrm{\&sigma;}}_{b(i-j)}}[P_{(i-j)}\left(u\right)-P_{(i-j)}^s]\mathrm{du}---\left(3\right)$

If the transient potential energy between faulty line excision posterior nodal point i, j increases immediately, σ is arranged then _{C (i-j)}=σ _{A (i-j)}, promptly transient potential energy is the active power P between node i, j in the transient process between failure removal posterior nodal point i, j _(i-j)(σ _(i-j)) with respect to the stable state after the fault

Deviation to phase angle difference σ between node i, j _(i-j)Integration;

The 4th step: the adjusting of reclosure time

(1) if two return or transient fault takes place for one of many back transmission lines in system's transient process, kept watch on the variation of the two ends phase angle difference of this circuit section non-fault line, getting its moment that reaches minimum value is reclosure time;

(2) if faulty line be non-two return or many back transmission lines in one of which; And be uniline; And its excision back electric power transmission network still is a connected graph, and reclosing is adjusted constantly and reached the moment of minimum value for the two ends phase angle difference of other branch road in the cut set that comprises this faulty line.

Utilize transmission line reclosing of the present invention online method for catching constantly; Can fully and effectively utilize the branch road information that measures; Optimum reclosure time accurately adjust in real time to improve the transient stability level of system, have and calculate simply, be easy to realize and the using value advantages of higher.

Description of drawings

P between Fig. 1 node i, j _(i-j)(σ _(i-j)) with σ _(i-j)Change curve (σ=σ _{(i-j) max}Overlap constantly).

P between Fig. 2 node i, j _(i-j)(σ _(i-j)) with σ _(i-j)Change curve (σ=σ _{(i-j) min}Overlap constantly).

Fig. 3 system localized network sketch map.

The differential seat angle of Fig. 4 YMC-HXB.

The transient potential energy of Fig. 5 branch road YMC-FTB.

Embodiment

A kind of transmission line reclosing of the present invention is online method for catching constantly, and its step is following:

The first step: the structure that keeps the transient energy function of model based on NETWORK STRUCTURE PRESERVING POWER SYSTEM

$V=\frac{1}{2}\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{M}_i{\mathrm{\&omega;}}_i^2+\underset{k=1}{\overset{l}{\mathrm{\&Sigma;}}}{\&Integral;}_{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="HDA0000101138480000012.png,HDA0000101138480000022.png"\; state="\{\{state\}\}">k</figure-callout>}}^0}^{{\mathrm{\&sigma;}}_k}[P_k\left(u\right)-P_k^s]\mathrm{du}+\underset{k=1}{\overset{l}{\mathrm{\&Sigma;}}}{\&Integral;}_{{\mathrm{\&sigma;}}_k^s}^{{\mathrm{\&sigma;}}_k^0}[P_k\left(u\right)-P_k^s]\mathrm{du}---\left(1\right)$

Wherein: V is the gross energy that NETWORK STRUCTURE PRESERVING POWER SYSTEM keeps model;

M _iBe the inertia time constant of i platform generator, m is generating board number;

ω _iBe the angular speed of i platform generator;

is the reference point of i bar branch road phase angle, and l is a way;

σ _iIt is i bar branch road phase angle;

is the active power of branch road k with respect to stable equilibrium point;

P _kActive power for branch road k.

Second step: the foundation of branch road transient potential energy function

$V_{\mathrm{PEk}}\left(t\right)={\&Integral;}_{t_0}^t{\mathrm{\&omega;}}_N[P_k\left(u\right)-P_k^s]{\mathrm{\&omega;}}_k^{\%}\left(u\right)\mathrm{du}---\left(2\right)$

Wherein: V _PEKBranch road potential energy for branch road k;

ω _NBe rated angular velocity;

is two ends bus angular frequency poor of branch road k.

The 3rd step: the transmission line transient characterisitics based on branch road potential energy are analyzed

If certain a pair of in the network returns the A-wire generation instantaneity short trouble in first and second power transmission lines, t _cFault, t are removed in circuit both sides switch motion constantly _RecThe circuit of automatic reclosing action constantly overlaps, and in this failure sequence process, the variation of the reactance between node i, j causes active power therebetween to change, thereby influences the level of sharing of the transient potential energy between node i, j.

For between node i, j, its transient potential energy can be described as:

$V_{\mathrm{PE}(i-j)}={\&Integral;}_{{\mathrm{\&sigma;}}_{a(i-j)}}^{{\mathrm{\&sigma;}}_{b(i-j)}}[P_{(i-j)}\left(u\right)-P_{(i-j)}^s]\mathrm{du}---\left(3\right)$

If the transient potential energy between faulty line excision posterior nodal point i, j increases immediately, σ is arranged then _{C (i-j)}=σ _{A (i-j)}Be that transient potential energy is the active power P between node i, j in the transient process between failure removal posterior nodal point i, j _(i-j)(σ _(i-j)) with respect to the stable state after the fault Deviation to phase angle difference σ between node i, j _(i-j)Integration.

When Fig. 1 and Fig. 2 are transient fault corresponding to different reclosing node i operate time, active power between j with the change curve of phase angle difference.

Wherein, before

-fault and circuit overlap the active power change curve between posterior nodal point i, j;

Active power change curve between -faulty line excision posterior nodal point i, j;

-corresponding to the active power value between systematic steady state situation lower node i, j.

t _cAfter the faulty line excision constantly, the active power between node i, j is at curve

If last variation is at σ _(i-j)The first time oscillatory process system synchronous operation between node i, j, " do not tear ", the size of the transient potential energy between this moment node i, j does

At [σ _{(i-j) c}, σ _{(i-j) max}] interval interior integration, its value is area A 1, if at σ _{(i-j) max}Circuit overlaps constantly, and the variation track that overlaps back active power is a curve At σ _(i-j)In the process that reduces, then the transient potential energy between node i, j does At [σ _{A (i-j)}, σ _{(i-j) max}] interval interior integration, in Fig. 1 area (A1+A2), this shows that the transient potential energy between node i, j increases, aggravate the imbalance of system's local energy, thereby will worsen the transient stability of system.

If after vibration finishes for the first time, at σ _(i-j)Reach its minimum value σ _{(i-j) min}Moment reclosing action, the size of the transient potential energy between this moment node i, j by

At [σ _{A1 (i-j)}, σ _{(i-j) min}] integration in interval is changed to At interval [σ _{A2 (i-j)}, σ _{(i-j) min}] interior integration; In Fig. 2 with the size of cartographic represenation of area transient potential energy; Then be changed to area A 3 by area (A2+A3), its value obviously reduces, and has therefore suppressed the variation of the transient potential energy between node i, j effectively; Alleviate it and be subjected to the impact degree of transient potential energy, helped the improvement of power system transient stability property.

The 4th step: the adjusting of optimum reclosure time

(1) if two return or transient fault takes place for one of many back transmission lines in system's transient process, kept watch on the variation of the two ends phase angle difference of this circuit section non-fault line, getting its moment that reaches minimum value is reclosure time.

(2) if faulty line be non-two return or many back transmission lines in one of which; And be uniline; And its excision back electric power transmission network still is a connected graph, and reclosing is adjusted constantly and reached the moment of minimum value for the two ends phase angle difference of other branch road in the cut set that comprises this faulty line.

Instantiation:

Utilize transmission line reclosing online method for catching constantly, under the situation to multi-machine power system generation transient fault, simulation calculation is carried out in adjusting of reclosing optimal time.

Simulation calculation is the example system with certain real system, and localized network is as shown in Figure 3.

If the three-phase transient fault occurs in the network the two A-wires that return in first and second circuits of 500kv between YMC-FTB, 0.1s A-wire two ends switch motion excision fault shows that through emulation second line two ends phase angle difference reaches maximum θ for the first time _YMC-FTBmaxMaximum and minimum θ _YMC-FTBminThe moment be respectively 0.54s and 1.26s.If the moment t of reclosing _RecWhen adjusting respectively, relatively do not overlapping and t to 0.52s and 1.26s _RecWhen being respectively 0.52s and 1.26s, the swing curve of generator YMC-HXB and the amplitude of variation of operating the transient potential energy of this cut set of posterior nodal point YMC-FTB are for the last time seen Fig. 5-8 (a) and 5-8 (b).

Visible from Fig. 4 and Fig. 5, when reclosure time is adjusted to 0.54s and 1.26s, compare with not overlapping, be diametrically opposite to the influence of power system transient stability property, promptly in the phase angle difference of failure removal posterior nodal point YMC-FTB at minimum θ _YMC-FTBminConstantly overlap the transient stability level that will improve system significantly, and in the phase angle difference of node YMC-FTB at maximum θ _YMC-FTBmaxConstantly overlap, with the vibration of the follow-up pendulum of further activating system.

Table 1 provide use branch road transient potential energy analytic approach to branch road YMC-FTB do not overlap after the fault, the cut set { result of calculation of the stability index of YMC-FTB} under 0.54s overlaps and 1.26s overlaps three kinds of situation.

Table 1 is corresponding to the SCI of different reclosure times _{{ YMC-FTB}}

Simulation result by the multimachine system shown in the table 1 can find out, exists during time of optimum reclosing, and be not the raising that necessarily faster coincidence helps power system transient stability property more, might cause the further deterioration of power system transient stability property on the contrary.

Visible by simulation result, the automatic reclosing that the present invention the proposes strategy of adjusting only depends on the information that dynamic observes of network local variable, and the variation of operational mode, malfunction and the network configuration of system is had strong adaptive capacity.

Claims (1)

1. an online method for catching of the transmission line reclosing moment is characterized in that it comprises the steps:

The first step: the structure that keeps the transient energy function of model based on NETWORK STRUCTURE PRESERVING POWER SYSTEM

Wherein: V is the gross energy that NETWORK STRUCTURE PRESERVING POWER SYSTEM keeps model,

M _iBe the inertia time constant of i platform generator, m is generating board number,

ω _iBe the angular speed of i platform generator,

is the reference point of i bar branch road phase angle; L is a way

σ _iBe i bar branch road phase angle,

is the active power of branch road k with respect to stable equilibrium point

P _kActive power for branch road k;

Second step: the foundation of branch road transient potential energy function

Wherein: V _PEKBe the branch road potential energy of branch road k,

ω _NBe rated angular velocity,

is two ends bus angular frequency poor of branch road k;

The 3rd step: the transmission line transient characterisitics based on branch road potential energy are analyzed

If certain a pair of in the network returns the A-wire generation instantaneity short trouble in first and second power transmission lines, t _cFault, t are removed in circuit both sides switch motion constantly _RecThe circuit of automatic reclosing action constantly overlaps, and in this failure sequence process, the variation of the reactance between node i, j causes active power therebetween to change, thereby influences the level of sharing of the transient potential energy between node i, j,

For between node i, j, its transient potential energy can be described as:

If the transient potential energy between faulty line excision posterior nodal point i, j increases immediately, σ is arranged then _{C (i-j)}=σ _{A (i-j)}, promptly transient potential energy is the active power P between node i, j in the transient process between failure removal posterior nodal point i, j _(i-j)(σ _(i-j)) with respect to the stable state after the fault

Deviation to phase angle difference σ between node i, j _(i-j)Integration;

The 4th step: the adjusting of reclosure time

(1) if two return or transient fault takes place for one of many back transmission lines in system's transient process, kept watch on the variation of the two ends phase angle difference of this circuit section non-fault line, getting its moment that reaches minimum value is reclosure time;

(2) if faulty line be non-two return or many back transmission lines in one of which; And be uniline; And its excision back electric power transmission network still is a connected graph, and reclosing is adjusted constantly and reached the moment of minimum value for the two ends phase angle difference of other branch road in the cut set that comprises this faulty line.

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