CN103236691B - Method of three-phase unbalance load flow calculation based on complex affine mathematical theory - Google Patents

Abstract

The invention discloses a method of three-phase unbalance load flow calculation based on the complex affine mathematical theory. The method includes inputting network original parameters including impedance values of each line and transformers, and active power and reactive power of each load node phase; initializing amplitude values and phase angles of each load node phase voltage; setting zero of iteration; calculating each phase injected current complex affine vector of each load node; starting from an end load node, performing summation calculation of branch current, and acquiring starting current complex affine values of each phase of each branch; and utilizing a set original load node voltage as a boundary condition to calculate voltage drop of each phase of each branch and end voltage complex affine values. By the method compared with the prior art, effective optimization of an uncertain load flow calculation interval algorithm is provided, interval load flow result conservative property, defects of an interval method are overcome, load flow of a distribution network containing uncertain information can be figured out effectively, and conservative property in the process of interval load flow calculation can be solved.

Description

Based on the three-phase unbalanced load flow computational methods of affine mathematical theory again

Technical field

The present invention relates to electric power system tide analysis field, particularly based on the distribution network three-phase unbalanced load flow computational methods of affine mathematical theory again.

Background technology

Along with the appearance of electricity market and the access of distributed power source, a large amount of uncertain factors can be there is, as uncertainty, the uncertainty of variable load, the uncertainty etc. of electric power original paper model parameter that distributed power source is exerted oneself in distribution system actual motion.On the one hand, traditional certainty tidal current computing method, when carrying out analytical calculation to the system with unascertained information, shows certain limitation.On the other hand, uncertain Load flow calculation there has been some application in power system planning, but due to the difficulty of problem own comparatively large, therefore adopt uncertain power flow algorithm can amount of calculation excessive, the problem of these two aspects is the difficult point in Load flow calculation always.

Following several method is mainly contained at present: random algorithm, fuzzy mathematics algorithm and interval algorithm for uncertain Load flow calculation.These three kinds of algorithms have applicable scope respectively, such as: for the random information possessing statistical property, can be represented the uncertainty of load by random algorithm with probability; For the uncertain factor not possessing statistical property, then can adopt fuzzy mathematics algorithm to process; For load prediction result inaccuracy but within the specific limits accurately time, adopt interval algorithm to solve very applicable.

When using interval algorithm to try to achieve approximate solution, there will be interval conservative property problem, namely causing the excessive calculation of tidal current that makes of interval range to lose meaning because the choice in computational process is improper.For the problem how reducing Interval Power Flow result conservative, affine mathematics is introduced in three-phase power flow by the present invention, sets up the three-phase unbalanced load flow computational methods based on multiple affine arithmetic.

Summary of the invention

Based on problems of the prior art, the present invention proposes a kind of three-phase unbalanced load flow computational methods based on affine mathematical theory again.

The present invention proposes a kind of camera marking method, the method comprises the following steps:

Carry out the electric power networks initial parameter of three-phase unbalanced load flow calculating needed for step (1), input, comprise each circuit and transformer impedance value, every phase active power of each load bus and reactive power;

The amplitude of step (2), the every phase voltage of each load bus of initialization and phase angle;

Step (3), by the iterations k zero setting of this computational methods flow process, k=0;

Step (4), according to the parameter in step (1), calculate the multiple affine vector of every phase Injection Current of each load bus:

${\hat{I}}_j^i={\left(\frac{{\hat{S}}_j^i}{{\hat{U}}_j^i}\right)}^{*}$

In formula: for the multiple affine current value of load bus j i-th phase, j=1 ... n, i=A phase, B phase, C phase;

for the multiple affine performance number of load bus j i-th phase;

for the multiple affine magnitude of voltage of load bus j i-th phase;

Step (5), from last load bus, by the read group total to branch current, obtain the multiple affine value of every phase top electric current of each bar branch road:

${\hat{I}}_j^i=\underset{m=1}{\overset{n}{\mathrm{\Σ}}}{\hat{I}}_m^i$

In formula: n be load bus j go out number;

be the m article of multiple affine current value going out an i phase;

Step (6) utilizes the voltage of the source load bus set as boundary condition, and the every phase voltage calculating each branch road is fallen and the multiple affine value of terminal voltage;

${\hat{U}}_j^i={\hat{U}}_{j-1}^i-\mathrm{\Δ}{\hat{U}}_j^i$

In formula:

for the multiple affine value of the voltage drop between load bus j and load bus j-1;

Step (7), judge whether iteration stops, if the voltage of the every phase of each bus is less than permissible value ε relative to the numerical bias of last iteration) then stop iteration:

$|{\left({\hat{U}}_j^i\right)}_k-{\left({\hat{U}}_j^i\right)}_{k-1}|<\mathrm{\&epsiv;};$

Otherwise, return step (5) and continue iteration, k=k+1; ;

Step (8), output result of calculation.

Compared with prior art, three-phase unbalanced load flow computational methods based on affine mathematical theory provided by the invention, effective improvement is proposed to uncertain Load flow calculation interval algorithm, affine mathematics is introduced three-phase power flow, reduce Interval Power Flow result conservative, make up the deficiency of interval method, more effectively can solve the trend of the distribution network containing uncertain information, solve the conservative in Interval Power Flow computational process better.

Accompanying drawing explanation

Fig. 1 is the flow chart of the three-phase unbalanced load flow computational methods based on affine mathematical theory of the present invention;

Fig. 2 is embodiment of the present invention IEEE13 load bus example winding diagram.

Embodiment

Below in conjunction with accompanying drawing, further describe specific implementation of the present invention.

Load fluctuation interval value is converted to again affine vector value, and computational methods of the present invention comprise the following steps:

Step one, input electric power network initial parameter, comprise each circuit and transformer impedance value in electric power networks, the active power of the every phase of each load bus and reactive power;

The amplitude of step 2, the every phase voltage of each load bus of initialization and phase angle;

Step 3, by iterations k zero setting, k=0;

Step 4, calculate the multiple affine vector of every phase Injection Current of each load bus:

${\hat{I}}_j^i={\left(\frac{{\hat{S}}_j^i}{{\hat{U}}_j^i}\right)}^{*}$

In formula: for the multiple affine current value of load bus j i-th phase, j=1 ... n, i=A, B, C;

for the multiple affine performance number of load bus j i-th phase;

for the multiple affine magnitude of voltage of load bus j i-th phase;

Step 5, from last load bus, push back calculating branch current, namely obtain the multiple affine value of top electric current of the every phase of each bar branch road:

${\hat{I}}_j^i=\underset{m=1}{\overset{n}{\mathrm{\&Sigma;}}}{\hat{I}}_m^i$

In formula: n be load bus j go out number;

be the m article of multiple affine current value going out an i phase;

The source load bus voltage that step 6, utilization have set, as boundary condition, calculates voltage drop and the multiple affine value of terminal voltage of the every phase of each branch road;

${\hat{U}}_j^i={\hat{U}}_{j-1}^i-\mathrm{\&Delta;}{\hat{U}}_j^i$

In formula: for the multiple affine value of the voltage drop between load bus j and load bus j-1.

Step 7, judgement stop, if meet iteration error requirement, stop, otherwise return (5) continuation iteration, k=k+1.Iteration ends criterion is that the voltage of the every phase of each bus is less than permissible value relative to the numerical bias of last iteration:

$|{\left({\hat{U}}_j^i\right)}_k-{\left({\hat{U}}_j^i\right)}_{k-1}|<\mathrm{\&epsiv;}$

Export result of calculation.

The distribution system having 13 load buses for certain below further illustrates technical scheme of the present invention.

The load data of table 1 example for this reason, other data of system are identical with IEEE13 load bus example, repeat no more.The present invention adopts famous value to carry out calculating (error precision is 0.01), and the result of output represents with the form of famous value.

Table 2 is 13 load bus distribution system three-phase unbalanced load flow result of calculations.

Table 1

Table 2

Result of calculation shows, the three-phase unbalanced load flow computational methods based on multiple affine theory that the present invention proposes can obtain the interval solutions of the uncertain trend of system, and interval method cannot solve problems.

Claims (2)

1., based on three-phase unbalanced load flow computational methods for affine mathematical theory again, it is characterized in that, the method comprises the following steps:

Carry out the electric power networks initial parameter of three-phase unbalanced load flow calculating needed for step (1), input, comprise each circuit and transformer impedance value, every phase active power of each load bus and reactive power;

The amplitude of step (2), the every phase voltage of each load bus of initialization and phase angle;

Step (3), by the iterations k zero setting of this computational methods flow process, k=0;

Step (4), according to the parameter in step (1), calculate the multiple affine vector of every phase Injection Current of each load bus:

${\hat{I}}_j^i={\left(\frac{{\hat{S}}_j^i}{{\hat{U}}_j^i}\right)}^{*}$

In formula: for the multiple affine current value of load bus j i-th phase, j=1 ... n, i=A phase, B phase, C phase;

for the multiple affine performance number of load bus j i-th phase;

for the multiple affine magnitude of voltage of load bus j i-th phase;

Step (5), from last load bus, by the read group total to branch current, obtain the multiple affine value of every phase top electric current of each bar branch road:

${\hat{I}}_j^i=\underset{m=1}{\overset{n}{\mathrm{\&Sigma;}}}{\hat{I}}_m^i$

In formula: n be load bus j go out number;

be the m article of multiple affine current value going out an i phase;

The voltage of the source load bus that step (6), utilization have set is as boundary condition, and the every phase voltage calculating each branch road is fallen and the multiple affine value of terminal voltage;

${\hat{U}}_j^i={\hat{U}}_{j-1}^i-\mathrm{\&Delta;}{\hat{U}}_j^i$

In formula:

for the multiple affine value of the voltage drop between load bus j and load bus j-1;

Step (7), judge whether iteration stops, if the voltage of the every phase of each bus is less than permissible value ε relative to the numerical bias of last iteration, then stop iteration:

$|{\left({\hat{U}}_j^i\right)}_k-{\left({\hat{U}}_j^i\right)}_{k-1}|<\mathrm{\&epsiv;};$

represent the voltage of the every phase of each bus; represent the voltage relative to the every phase of each bus of last iteration;

Otherwise, return step (5) and continue iteration, k=k+1; ;

Step (8), output result of calculation.

2. the three-phase unbalanced load flow computational methods based on affine mathematical theory again according to claim 1, is characterized in that, permissible value ε=10 of described numerical bias ^-6.