CN104779627A - Real-time optimizing and tuning method for gateway reactive intervals of main transformers in radiant power grid - Google Patents

Abstract

The invention discloses a real-time optimizing and tuning method for reactive intervals of main transformers in a radiant power grid. The real-time optimizing and tuning method comprises the following steps of: acquiring parameter information of the radiant power grid from an information management system database and establishing a radiant power grid model; acquiring real-time operation data of the radiant power grid by utilizing a power grid data acquiring and monitoring system; calculating an optimal value QL of reactive power of a line tail end; calculating an absolute value of QL, dividing the absolute value into n parts and marking a value of each part as Ai; calculating the average number Bi of Ai and 0 and adding and subtracting a margin beta on the basis of Bi to form a gateway reactive optimization taking value interval [Bi-beta, Bi+beta] of each main transformer; and after time T, carrying out a new round of calculation on the gateway reactive optimization taking value interval to obtain a new gateway reactive optimization taking value interval.

Description

The real-time optimization setting method in idle interval, main transformer critical point in a kind of radial system

Technical field

The present invention relates to power system reactive power operation method, more particularly, relate to the real-time optimization setting method in idle interval, main transformer critical point in a kind of radial system.

Background technology

The reactive power/voltage control of electrical network is related to fail safe and the economy of operation of power networks, for ensureing quality of voltage and reactive power layering and zoning in-situ balancing, need control, to improve reliability and the economy of transmission and distribution network to the reactive voltage of transformer station.For the radial system of 110kV, the reactive power/voltage control of 110kV transformer station mainly contains two kinds, one utilizes automatic voltage control system (Automatic voltage control, AVC) transformer station included in the idle work optimization calculating of the whole network, Real-Time Monitoring operation of power networks state also optimization calculates the substation bus bar voltage of transformer station and the control range of main transformer reactive power (or power factor); Another kind of Ze Shi transformer station utilizes self information system on the spot, adopts the comparatively simple control strategy such as nine-zone diagram, 17 Qu Tu to carry out reactive power/voltage control.

In above-mentioned way, the former considers the whole network operating condition, and be optimized the reactive voltage of transformer station and adjust, optimum results is closing to reality situation more, but owing to too relying in state estimation and automatization level and then making that its feasibility is low and control effects is poor; The latter pays close attention to idle, voltage two indices, although the application shortcoming be convenient in engineering considers that the operating conditions such as network load level are to the demand of reactive power/voltage control, its controling parameters based on the experience run, lacks clear and definite optimization foundation mostly.

Therefore, in order to better instruct the application on Practical Project, need a kind of method can adjusted to main transformer of transformer substation critical point wattles power economic equivalent, both network load level run operating mode had been considered on the impact of main transformer critical point wattles power economic equivalent value, there is again the practicality of engineering, power grid security is run economically.

Summary of the invention

The object of the invention is to: the real-time optimization setting method that idle interval, main transformer critical point in a kind of radial system is provided, both network load level run operating mode had been considered on the impact of main transformer critical point wattles power economic equivalent value, there is again the practicality of engineering, power grid security is run economically.

To achieve these goals, the invention provides the real-time optimization setting method in idle interval, main transformer critical point in a kind of radial system, comprise the following steps:

(1) from Data in Information Management System storehouse, obtain the parameter information of radial system, set up radial system model;

(2) electric network data collection and supervisory control system is utilized to gather the real-time running data of radial system;

(3) the optimal value Q of computational scheme end reactive power _l; Described optimum refers to and makes circuit active loss in radial system be minimum;

(4) Q is calculated _labsolute value | Q _l|, and will | Q _l| be distributed into n part, every a value is designated as A _i;

(5) A is calculated _iwith 0 average B _i, and at B _ibasis on add, subtract the critical point idle work optimization interval [B that nargin β forms each main transformer _i-β, B _i+ β]; The critical point idle work optimization interval of described each main transformer refers to the optimization span of each main transformer high-pressure side reactive power;

(6) after elapsed time T, carry out the calculating of the critical point idle work optimization interval of a new round according to above-mentioned steps, obtain new critical point idle work optimization interval, the real-time optimization realizing idle interval, main transformer critical point in radial system is adjusted.Described period of time T, namely electrical network is optimized the time cycle of control, can regulate accordingly according to the actual needs of electrical network.

As a modification of the present invention, described parameter information comprises the topological structure of radial system, the substitutional resistance parameter R of transmission line _l, equivalent reactance parameter X _l, equivalent susceptance parameter B _l, the model of each main transformer, configuration capacity, described real-time running data comprises transmission line head end working voltage U _g, total burden with power P of sending under transmission line _l, the on high-tension side burden with power P of each main transformer _ti, subscript i represents main transformer sequence number, and i=1 ~ n, n are the total number of units of main transformer in radial system.

As a modification of the present invention, the optimal value Q of described line end reactive power _l, refer to the size of the minimum transmission line end reactive power of trying to achieve for target function of transmission line active loss, determine by following formula,

$Q_L=\frac{B_L{(U_G+\sqrt{{U_G}^2-4P_L{R}_L})}^2}{8}+\frac{(B_L{X}_L-2)X_L{(U_G-\sqrt{{U_G}^2-4P_L{R}_L})}^2}{8{R_L}^2}.$

As a modification of the present invention, | Q _l| distribution by burden with power P on high-tension side with each main transformer _tisize be inversely proportional to and distribute, apportioning cost A _idetermine by following formula,

$A_i={(-1)}^k(1-\frac{P_{\mathrm{Ti}}}{P_L})\frac{\left|Q_L\right|}{n-1}$

In formula, the value of variable k is according to Q _lvalue positive and negative and determine, if Q _lbe more than or equal to 0, then make variable k=0; If Q _lbe less than 0, then make variable k=1.

Compared with prior art, contemplated by the invention the operating condition that electrical network is real-time, the real-time optimization carrying out idle interval, radial system main transformer critical point is adjusted, compensate for existing to idle interval, critical point by rule of thumb, the unification deficiency of adjusting; The method that the idle range optimization in radial system main transformer critical point proposed is adjusted, does not relate to complicated idle work optimization iterative computation, the real-time optimal control of electrical network of being more convenient for.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, structure of the present invention and Advantageous Effects thereof are described in detail.

Fig. 1 is the real-time optimization setting method flow chart in idle interval, main transformer critical point in radial system of the present invention.

Fig. 2 is the computation model figure of certain radial system.

Embodiment

In order to make goal of the invention of the present invention, technical scheme and Advantageous Effects thereof more clear, below in conjunction with the drawings and specific embodiments, the present invention is further elaborated.Should be understood that, the embodiment described in this specification is only used to explain the present invention, is not intended to limit the present invention.

Refer to Fig. 1, the idle interval real-time optimization setting method in main transformer critical point in a kind of radial system of the present invention, comprises the following steps:

(1) from Data in Information Management System storehouse, obtain the parameter information of radial system, comprise the substitutional resistance parameter R of the topological structure of radial system, transmission line _l, equivalent reactance parameter X _l, equivalent susceptance parameter B _l, the model of each main transformer, configuration capacity, set up radial system model;

(2) utilize electric network data collection and supervisory control system to gather the real-time running data of radial system, comprise transmission line head end working voltage U _g, total burden with power P of sending under transmission line _l, the on high-tension side burden with power P of each main transformer _ti, subscript i represents main transformer sequence number, and i=1 ~ n, n are the total number of units of main transformer in radial system;

(3) the optimal value Q of computational scheme end reactive power _l; Described optimum refers to and makes circuit active loss in radial system be minimum;

(4) Q is calculated _labsolute value | Q _l|, and will | Q _l| be distributed into n part, every a value is designated as A _i;

(5) A is calculated _iwith 0 average B _i, and at B _ibasis on add, subtract the critical point idle work optimization interval [B that nargin β forms each main transformer _i-β, B _i+ β]; The critical point idle work optimization interval of described each main transformer refers to the optimization span of each main transformer high-pressure side reactive power;

(6) after elapsed time T, carry out the calculating of the critical point idle work optimization interval of a new round according to above-mentioned steps, obtain new critical point idle work optimization interval, the real-time optimization realizing idle interval, main transformer critical point in radial system is adjusted.

The optimal value Q of the line end reactive power described in step of the present invention (3) _l, refer to the size of the minimum transmission line end reactive power of trying to achieve for target function of transmission line active loss, obtain by following methods:

Consider the π type Equivalent Model of transmission line and the substitutional resistance parameter R of radial system transmission line _l, equivalent reactance parameter X _l, equivalent susceptance parameter B _l, head end working voltage U _g, suppose the end working voltage U of transmission line _l, the power that transmission line head end injects transmission line is P _g+ jQ _g, then the power loss Δ P of transmission line _l+ j Δ Q _land the voltage relationship at transmission line first, last two ends can be expressed as

${\mathrm{\ΔP}}_L+\mathrm{j\Δ}{Q}_L=\frac{P_G^2+{(Q_G+\frac{1}{2}{B}_L{U}_G^2)}^2}{U_G^2}(R_L+j{X}_L)---\left(1\right)$

$U_L^2={[U_G-\frac{P_G{R}_L+(Q_G+\frac{1}{2}{B}_L{U}_G^2)X_L}{U_G}]}^2+{\left[\frac{P_G{X}_L-(Q_G+\frac{1}{2}{B}_L{U}_G^2)R_L}{U_G}\right]}^2---\left(2\right)$

Row with merit power balance equation, then have:

P _G-△P _L-P _L＝0 (3)

Formula (1) ~ (2) are substituted into formula (3), can obtain:

$P_G-\frac{P_G^2+{(Q_G+\frac{1}{2}{B}_L{U}_G^2)}^2}{U_G^2}{R}_L-P_L=0---\left(4\right)$

For ask make the active loss of radial system circuit minimum time line end transmission reactive power value Q _l, Schilling formula (4) is to Q _gcarry out differentiate, ask Q _gminimum Q _gmin, then have:

$\frac{{\∂P}_G}{{\∂Q}_G}-2\frac{R_L}{U_G^2}[P_G\frac{{\∂P}_G}{{\∂Q}_G}+Q_G+\frac{1}{2}{B}_L{U}_G^2]=0---\left(5\right)$

Order ${\∂P}_G/{\∂Q}_G=0,$ Can obtain:

$Q_{G\min }=-\frac{1}{2}{B}_L{U}_G^2---\left(6\right)$

The reactive power injecting transmission line when transmission line head end is Q _gmin, the reactive power value of now line end transmission is optimum, i.e. Q _l, row write reactive power equilibrium equation, then have:

$Q_{G\min }+\frac{1}{2}{B}_L{U}_G^2-{\mathrm{\ΔQ}}_L+\frac{1}{2}{B}_L{U}_L^2-Q_L=0---\left(7\right)$

By the optimal value Q that formula (6) substitutes into formula (2), (4), (7) can be calculated line end reactive power _lanalytical expression be:

$Q_L=\frac{B_L{(U_G+\sqrt{{U_G}^2-4P_L{R}_L})}^2}{8}+\frac{(B_L{X}_L-2)X_L{(U_G-\sqrt{{U_G}^2-4P_L{R}_L})}^2}{8{R_L}^2}---\left(8\right)$

The parameter information of radial system and the real-time running data that gathers are substituted into formula (8) calculate, then can obtain the optimal value Q of line end reactive power _lvalue.

A in step of the present invention (5) _iacquisition methods as follows:

Because active loss and the on high-tension side burden with power of each main transformer of main transformer, load or burden without work are relevant, the on high-tension side burden with power P of each main transformer _titime larger, for reducing main transformer active loss, the absolute magnitude of the reactive power that each main transformer high-pressure side is flow through should be reduced as far as possible, for this reason, consider that its principle of distributing is: according to P _tisize carry out inverse proportion distribution, therefore A _iobtain by formula (9):

$A_i={(-1)}^k(1-\frac{P_{\mathrm{Ti}}}{P_L})\frac{\left|Q_L\right|}{n-1}---\left(9\right)$

For ensureing each sendout A _isum equals optimal value Q _l, formula determines A by variable k in (9) _ithe positive negativity of value, and in formula the value of variable k according to Q _lvalue positive and negative and determine, if Q _lbe more than or equal to 0, then make variable k=0; If Q _lbe less than 0, then make variable k=1.

Calculate A _iwith 0 average B _i, and at B _ibasis on add, subtract the critical point idle work optimization interval [B that nargin β forms each main transformer _i-β, B _i+ β] in, described gets A _iwith 0 average B _iintermediate value as critical point idle work optimization interval is because in radial system, if only consider, circuit is optimum, and namely the active loss of circuit is minimum, then the critical point of each main transformer should control at A without work value _iif, and only consider that the active loss of this main transformer is minimum, then optimum critical point should control to be 0 without work value, and the active loss considering main transformer and circuit is minimum, gets A in the present invention _iwith 0 average as the intermediate value in idle work optimization interval, critical point.

In the present invention, by the critical point idle work optimization interval [B of each main transformer obtained _i-β, B _i+ β], the control range of each main transformer high-pressure side reactive power can be determined, elapsed time cycle T, carry out the calculating of the critical point idle work optimization interval of a new round, obtain new critical point idle work optimization interval, the real-time optimization realizing idle interval, main transformer critical point in radial system is adjusted.Described period of time T, namely electrical network is optimized the time cycle of control, can regulate accordingly according to the actual needs of electrical network.

For south electric network 110kV radial system, method flow of the present invention and relevant data are described below:

(1) obtain the parameter information of radial system, comprise the topological structure of radial system, transmission line substitutional resistance parameter R _l, equivalent reactance parameter X _l, equivalent susceptance parameter B _l, each main transformer model, configuration capacity, set up radial system model; As shown in Figure 2, and transmission line equivalent parameters is R to radial system computation model figure _l=0.2985 Ω, X _l=1.50 Ω, B _l=6.8*10^-5S _,.

(2) the head end working voltage U of Real-time Collection radial system transmission line _g, total burden with power P of sending under transmission line _l, the on high-tension side burden with power P of each main transformer _ti, subscript i represents main transformer sequence number, and i=1 ~ n, n are the main transformer number of radial system.

Three main transformers, then n=3 are had in this radial system; As shown in table 1 by the trip information of this radial system of AVC system acquisition:

Table 1 radial system trip information

Variable	U G	P T	P T1	P T2	P T3
						Numerical value	116kV	50MW	18MW	24MW	8MW

(3) the optimal value Q of the reactive power of computational scheme tip transition _l; Described optimum refers to the reactive power value of line end transmission when making the active loss of radial system circuit minimum;

Optimal value Q _l, obtain by formula (8), calculate Q _l=0.1772Mvar.

(4) Q is calculated _labsolute value | Q _l|, and will | Q _l| be distributed into n part, every a value is designated as A _i, through type (9) obtains, and calculates:

A ₁＝0.0567Mvar，A ₂＝0.0461Mvar，A ₃＝0.0744Mvar。

(5) A is calculated _iwith 0 average B _i, and at B _ibasis on add, subtract the critical point idle work optimization interval [B that nargin β forms each main transformer _i-β, B _i+ β]; Nargin β value 5Mvar.

The critical point idle work optimization interval that then can obtain main transformer 1 is [-4.9716,5.0284] Mvar; The critical point idle work optimization interval of main transformer 2 is [-4.9770,5.0230] Mvar; The critical point idle work optimization interval of main transformer 3 is [-4.9628,5.0372] Mvar;

(6) after elapsed time T, carry out the calculating of new round interval value according to above-mentioned steps, the real-time optimization realizing idle interval, radial system critical point is adjusted.For ensureing real-time optimization, in this example, T can value 1 minute.

The announcement of book and instruction according to the above description, those skilled in the art in the invention can also carry out suitable change and amendment to above-mentioned execution mode.Therefore, the present invention is not limited to embodiment disclosed and described above, also should fall in the protection range of claim of the present invention modifications and changes more of the present invention.In addition, although employ some specific terms in this specification, these terms just for convenience of description, do not form any restriction to the present invention.

Claims (4)

1. the real-time optimization setting method in idle interval, main transformer critical point in radial system, is characterized in that comprising the following steps:

(1) from Data in Information Management System storehouse, obtain the parameter information of radial system, set up radial system model;

(2) electric network data collection and supervisory control system is utilized to gather the real-time running data of radial system;

(3) the optimal value Q of computational scheme end reactive power _l, described optimum refers to and makes circuit active loss in radial system be minimum;

(4) Q is calculated _labsolute value | Q _l|, and will | Q _l| be distributed into n part, every a value is designated as A _i;

(5) A is calculated _iwith 0 average B _i, and at B _ibasis on add, subtract the critical point idle work optimization interval [B that nargin β forms each main transformer _i-β, B _i+ β]; The critical point idle work optimization interval of described each main transformer refers to the optimization span of each main transformer high-pressure side reactive power;

(6) after elapsed time T, carry out the calculating of the critical point idle work optimization interval of a new round according to above-mentioned steps, obtain new critical point idle work optimization interval, the real-time optimization realizing idle interval, main transformer critical point in radial system is adjusted.

2. the real-time optimization setting method in idle interval, main transformer critical point in radial system according to claim 1, it is characterized in that, described parameter information comprises the topological structure of radial system, the substitutional resistance parameter R of transmission line _l, equivalent reactance parameter X _l, equivalent susceptance parameter B _l, the model of each main transformer, configuration capacity, described real-time running data comprises transmission line head end working voltage U _g, total burden with power P of sending under transmission line _l, the on high-tension side burden with power P of each main transformer _ti, subscript i represents main transformer sequence number, and i=1 ~ n, n are the total number of units of main transformer in radial system.

3. the real-time optimization setting method in idle interval, main transformer critical point in radial system according to claim 2, is characterized in that, the optimal value Q of described line end reactive power _l, refer to the size of the minimum transmission line end reactive power of trying to achieve for target function of transmission line active loss, determine by following formula,

$Q_L=\frac{B_L{(U_G+\sqrt{{U_G}^2-{4P}_L{R}_L})}^2}{8}+\frac{(B_L{X}_L-2)X_L{(U_G-\sqrt{{U_G}^2-4P_L{R}_L})}^2}{{{8R}_L}^2}.$

4. the real-time optimization setting method in idle interval, main transformer critical point in radial system according to claim 2, is characterized in that, | Q _l| distribution by burden with power P on high-tension side with each main transformer _tisize be inversely proportional to and distribute, apportioning cost A _idetermine by following formula,

$A_i={(-1)}^k(1-\frac{P_{\mathrm{Ti}}}{P_L})\frac{{|Q}_L|}{n-1}$

In formula, the value of variable k is according to Q _lvalue positive and negative and determine, if Q _lbe more than or equal to 0, then make variable k=0; If Q _lbe less than 0, then make variable k=1.