CN1725591A - Adaptive regulation method of bus protection ratio brake coefficient based on bus connection current - Google Patents

Abstract

An adaptive regulation method for a bus protection ratio braking coefficient of a microcomputer bus protection based on bus bar current includes the following steps: evaluating the bus bar circulation coefficient of a bus bar based on two bus bar currents correlated to the bus bar, regulating the previous ratio brake coefficient to get the regulated ratio brake coefficient to be used in the microcomputer bus bar protection differential criterion to increase its reliability.

Description

A kind of bus protection ratio brake coefficient self-adapting regulation method that joins electric current based on mother

Technical field

The present invention is applied to the electric power system PC bus protection.

Background technology

Along with improving and expansion of electric power system electric network composition, in order to guarantee the stability of system, increasing bus-bar system is taked ring busbars wiring pattern (the single segmentation wiring of two mothers and two female pair of segmentation wiring).Influence because of system configuration when the cyclization of ring busbars system moves the generating region internal fault may produce the situation that fault current flows out; in case there is the fault current outflow will cause the stalling current in the bus protection differential current criterion to increase; if inappropriate reduction ratio brake coefficient; bus protection will tripping, and the safe and stable operation of electric power system is produced ill effect.The PC bus protection that is applicable to the ring busbars system has at present all been taked some methods of adjustment, and protective device is provided with two ratio brake coefficients, and one is the high value of ratio brake coefficient, and another is the ratio brake coefficient low value.Method of adjustment substantially can be divided two classes: to be the PC bus protection device judge whether automatically that according to the operational mode at scene needs carry out the ratio brake coefficient adjustment to a class, then automatically ratio brake coefficient reduced to the ratio brake coefficient low value if need to adjust; The another kind of authority of adjustment rate restraint coefficient that will whether need is given the field operator, when need adjusting, artificial judgement undertaken by foreign intervention, such as switching pressing plate etc., when being checked through intervention information, device automatically ratio brake coefficient is reduced to the ratio brake coefficient low value.These two kinds of methods of adjustment are serious to people's dependence; the user of operative installations must the fault behavior of analytical system closely under the unpredictable prerequisite of some condition of system; the ratio brake coefficient low value is set; and in case enter the adjustment state; device with regard to long-time running in low ratio brake coefficient state, to the protection reliability effect bigger.

For the bus protection that guarantees the ring busbars system is having action message under the prerequisite that flows out electric current; the present invention has taked to join based on mother the self-adapting regulation method of electric current; automatically adjust the ratio brake coefficient in the bus protection differential criterion, alleviated the dependence of device the people.

The PC bus protection differential criterion all is equal to following criterion both at home and abroad at present:

$\left\{\begin{array}{c}{i}_{\mathrm{cd}}\≥I_{\mathrm{zd}}\\ i_{\mathrm{cd}}\≥K\·i_{\mathrm{zd}}\end{array}\right.$

I wherein _CdBe differential current, i _ZdBe stalling current, I _ZdBe differential current threshold definite value.

This criterion hinders the electric current outflow for some reason in the ring busbars system influence may cause stalling current i _ZdIncrease, if do not cut ratio brake coefficient K, differential criterion may tripping.

Summary of the invention

The present invention proposes a kind of bus protection ratio brake coefficient self-adapting regulation method that joins circulation based on mother.

For a certain section bus in the ring busbars system when the electric current of outflow is arranged its equivalent circuit diagram as shown in Figure 1, two female connections that female connection 1 and female connection 2 this section of signal buses are connected.The present invention has defined the notion of female circulation coefficient:

$K_{\mathrm{hl}}=\frac{|K_{\mathrm{ml}1}{\·i}_{\mathrm{ml}1}+K_{\mathrm{ml}2}\·i_{\mathrm{ml}2}|}{|K_{\mathrm{ml}1}\·i_{\mathrm{ml}1}|+|K_{\mathrm{ml}2}\·i_{\mathrm{ml}2}|}$

i _Ml1Join 1 current sampling data, i for t is female constantly _Ml2Join 2 current sampling data, K for t is female constantly _Ml1For mother joins 1 coefficient, when mother joins 1 polarity K when consistent with bus _Ml1=1, otherwise K _Ml1=-1.K _Ml2For mother joins 2 coefficient, when mother joins 2 polarity K when consistent with bus _Ml2=1, otherwise K _Ml2=-1, K _HlFor t constantly the mother of this section bus join circulation coefficient.

T mother constantly joins circulation coefficient and is among Fig. 1 $K_{\mathrm{hl}}=\frac{|i_1^{\′}-(i_1^{\′}+i_2)|}{\left|i_1^{\′}\right|+|i_1^{\′}+i_2|}=\frac{\left|i_2\right|}{\left|i_1^{\′}\right|+|i_1^{\′}+i_2|},$ The ratio of bus differential electric current and stalling current is $K=\frac{|i_1+(i_1^{\′}+i_2)-i_1^{\′}|}{\left|i_1\right|+|i_1^{\′}+i_2|+\left|i_2^{\′}\right|}=\frac{|i_1+i_2|}{\left|i_1\right|+|i_1^{\′}+i_2|+\left|i_1^{\′}\right|}.$

If i ₁'=ai ₁(0≤a≤1).

1, i ₁' and i ₂Same symbol

$K_{\mathrm{hl}}=\frac{\left|i_2\right|}{2\left|i_1^{\′}\right|+\left|i_2\right|}=\frac{\left|i_2\right|}{\left|i_1\right|2a+\left|i_2\right|}$

$K=\frac{|i_1+i_2|}{\left|i_1\right|+2\left|i_1^{\′}\right|+\left|i_2\right|}=\frac{\left|i_1\right|+\left|i_2\right|}{\left|i_1\right|(1+2a)+\left|i_2\right|}$

0≤a≤1， $\frac{\left|i_2\right|}{2\left|i_1\right|+\left|i_2\right|}\≤K_{\mathrm{hl}}\≤1,$ $\frac{\left|i_1\right|+\left|i_2\right|}{3\left|i_1\right|+\left|i_2\right|}\≤K\≤1$

When a=0, K _Hl=1, K=1, do not have the electric current of outflow this moment, need not to carry out the circulation adjustment.

When a=1, $K_{\mathrm{hl}}=\frac{\left|i_2\right|}{2\left|i_1\right|+\left|i_2\right|},$ $K=\frac{\left|i_1\right|+\left|i_2\right|}{3\left|i_1\right|+\left|i_2\right|},$ If | i ₁| be far longer than | i ₂|, K then _Hl=0, $K=\frac{1}{3},$ This moment is the most serious, and flowing out electric current is 50% of inflow current, in order to guarantee the protection action, must reduce ratio brake coefficient make it less than

If | i ₂| be far longer than | i ₁|, K then _Hl=1, K=1, flow out electric current and be far smaller than inflow current this moment, and ratio brake coefficient need not to adjust; If | i ₂|=| i ₁|, then $K_{\mathrm{hl}}=\frac{1}{3},$ $K=\frac{1}{2},$ Reducing ratio brake coefficient makes it promptly to satisfy operating criterion less than 0.5 protection.

2, i ₁' and i ₂Anti-symbol

| i ₂| 〉=| i ₁' | the time K _Hl=1, $K=\frac{|i_1+i_2|}{\left|i_1\right|+\left|i_2\right|}\≤1,$ Satisfy differential criterion this moment, ratio brake coefficient does not have to reduce because of the influence of circulation, so need not to carry out the circulation adjustment.

| i ₂|≤| i ₁' |=a|i ₁| the time $K_{\mathrm{hl}}=\frac{\left|i_2\right|}{2a\left|i_1\right|-\left|i_2\right|},$ $K=\frac{\left|i_1\right|-\left|i_2\right|}{\left|i_1\right|(1+2a)-\left|i_2\right|}.$

0≤a≤1， $\frac{\left|i_2\right|}{2\left|i_1\right|-\left|i_2\right|}\≤K_{\mathrm{hl}}\≤1,$ $\frac{\left|i_1\right|-\left|i_2\right|}{3\left|i_1\right|-\left|i_2\right|}\≤K\≤1$

If a|i ₁| very little, then | i ₂| also very little, K is set this moment _Hl=1, K ≈ 1 need not the adjustment rate restraint coefficient.When a=1 $K_{\mathrm{hl}}=\frac{\left|i_2\right|}{2\left|i_1\right|-\left|i_2\right|},$ $K=\frac{\left|i_1\right|-\left|i_2\right|}{3\left|i_1\right|-\left|i_2\right|}.$ When troubles inside the sample space | i ₁| will be far longer than | i ₂|, this moment is the most serious, and flowing out electric current is 50% of inflow current, K _Hl=0, $K=\frac{1}{3},$ In order to guarantee protection action, must reduce ratio brake coefficient make it less than

Our ratio brake coefficient of adjusting is K when obtaining female connection circulation coefficient, and the ratio brake coefficient of self adaptation adjustment is:

K _tz＝0.3+(K-0.3)·K _hl

Work as K _Hl=1 o'clock K _Tz=K need not to adjust;

Work as K _Hl=0 o'clock K _Tz=0.3, satisfy the harshest situation.

In view of above analysis as can be known: 0≤K _Hl≤ 1,0.3≤K _Tz≤ K.

Take to reduce existing method and be in the bus protection integrity problem that low ratio brake coefficient is implied for a long time based on the bus protection ratio brake coefficient self-adapting regulation method that mother joins electric current.

Description of drawings

Fig. 1 is that ring busbars system failure electric current distributes schematic diagram.

Fig. 2 is the two female single segmentation wiring schematic diagrams of electric power system.

Fig. 3 is two female single sectionalized bus system operation modes one.

Fig. 4 is two female single sectionalized bus system operation modes one of accident analysis schematic diagrames once.

Fig. 5 be two female single sectionalized bus system operation modes once the accident analysis schematic diagram two.

Fig. 6 be two female single sectionalized bus system operation modes once the accident analysis schematic diagram three.

Fig. 7 is two female single sectionalized bus system operation modes two.

Fig. 8 is one of two two times accident analysis schematic diagrames of female single sectionalized bus system operation mode.

Fig. 9 is two of two two times accident analysis schematic diagrames of female single sectionalized bus system operation mode.

Figure 10 is three of two two times accident analysis schematic diagrames of female single sectionalized bus system operation mode.

Figure 11 is two female single sectionalized bus system operation modes three.

Figure 12 is one of two three times accident analysis schematic diagrames of female single sectionalized bus system operation mode.

Figure 13 is two of two three times accident analysis schematic diagrames of female single sectionalized bus system operation mode.

Figure 14 is three of two three times accident analysis schematic diagrames of female single sectionalized bus system operation mode.

Specific embodiments

Below be example explanation specific embodiments with the single sectionalized bus of two mothers system, the two sectionalized bus system implementation plans of two mothers are identical.

Fig. 2 is the typical wiring figure of the two female single sectionalized bus of electric power system system, it comprises three sections buses and three female connection/segmentations, at interval I-II1 ..., I-IIn runs on bus I or bus II at interval, at interval III-II1 ..., III-IIm runs on bus III or bus II at interval.

Analyze the situation of the female troubles inside the sample spaces of I at the various operational modes of Fig. 2, the female troubles inside the sample space analysis classes of II, III seemingly.

1, mode one

Female connection 1, female connection 2 and segmentation (female connection 3) cyclization operation, the operation schematic diagram as shown in Figure 3.

1) no grid switching operation, mother I, mother II, the female little difference ring independence of III, the accident analysis schematic diagram is as shown in Figure 4.

The female differential current of I:

$i_{\mathrm{cd}}=|i+i_{\mathrm{ml}3}+i_{\mathrm{ml}1}|=|i+(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2)-i_2|=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+\left|i_{\mathrm{ml}3}\right|+\left|i_{\mathrm{ml}1}\right|=\left|i\right|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|+2\left|i_2\right|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|i_{\mathrm{ml}1}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}1}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{|i_2-(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2)|}{\left|i_2\right|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2|}=\frac{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|}{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|+2\left|i_2\right|}$

This moment the bus-bar system operation with closed ring, female connection circulation coefficient is along with flowing out current i ₂Vary in size and change.Work as i ₂=0, little poor stalling current is constant, and female connection circulation coefficient is 1, and ratio brake coefficient is a setting value; Work as i ₂Increase, little poor stalling current increases, and female connection circulation coefficient reduces, and ratio brake coefficient reduces.

2) interconnected branch road is arranged between bus I and the II, no interconnected branch road between bus III and the II, the accident analysis schematic diagram is as shown in Figure 5.

Merge into one section bus and handle bus I and bus II are interconnected this moment.

The female differential current of I: $i_{\mathrm{cd}}=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_{\mathrm{ml}3}-i_{\mathrm{ml}2}|=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}\left|i_j\right|+\left|i_{\mathrm{ml}3}\right|+\left|i_{\mathrm{ml}2}\right|=\left|i\right|+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}\left|i_j\right|+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}\left|i_j\right|+2\left|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}\right|i_j\left|{+i}_2\right|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|{-i}_{\mathrm{ml}2}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}2}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{|(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_2)-(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2)|}{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_2|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2|}=\frac{\left|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j\right|}{\left|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j\right|+2|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_2|}$

This moment the bus-bar system operation with closed ring, female connection circulation coefficient is along with flowing out electric current Vary in size and change.When $\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_2=0,$ Little poor stalling current is constant, and female connection circulation coefficient is 1, and ratio brake coefficient is a setting value; When

Increase, little poor stalling current increases, and female connection circulation coefficient reduces, and ratio brake coefficient reduces.

3) no interconnected branch road between bus I and the II has interconnected branch road between bus III and the II, and the accident analysis schematic diagram as shown in Figure 6.

Merge into one section bus processing with bus III and bus II this moment.

The female differential current of I: $i_{\mathrm{cd}}=|i-i_{\mathrm{ml}1}+i_{\mathrm{ml}3}|=|i-i_2+(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2)|=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+\left|i_{\mathrm{ml}3}\right|+\left|i_{\mathrm{ml}1}\right|=\left|i\right|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|+2\left|i_2\right|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|i_{\mathrm{ml}1}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}1}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{|i_2-(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2)|}{\left|i_2\right|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2|}=\frac{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|}{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|+2\left|i_2\right|}$

This moment the bus-bar system operation with closed ring, female connection circulation coefficient is along with flowing out current i ₂Vary in size and change.Work as i ₂=0, little poor stalling current is constant, and female connection circulation coefficient is 1, and ratio brake coefficient is a setting value; Work as i ₂Increase, little poor stalling current increases, and female connection circulation coefficient reduces, and ratio brake coefficient reduces.

2, mode two

Female connection 3 closes, and female connection 1 closes, and female connection 2 disconnects.The operation schematic diagram as shown in Figure 7.

1) no grid switching operation, mother I, mother II, the female little difference ring independence of III, the accident analysis schematic diagram is as shown in Figure 8.

The female differential current of I: $i_{\mathrm{cd}}=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+\left|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j\right|+|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|i_{\mathrm{ml}1}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}1}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|}{\left|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j\right|+\left|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j\right|}=1$

Bus-bar system open loop operation this moment, female connection circulation coefficient is 1, ratio brake coefficient is a setting value.

2) interconnected branch road is arranged between bus I and the II, no interconnected branch road between bus III and the II, the accident analysis schematic diagram is as shown in Figure 9.

Merge into one section bus and handle bus I and bus II are interconnected this moment.

The female differential current of I: $i_{\mathrm{cd}}=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+\left|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j\right|+\left|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j\right|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|{-i}_{\mathrm{ml}2}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}2}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{\left|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j\right|}{\left|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j\right|}=1$

Bus-bar system open loop operation this moment, female connection circulation coefficient is 1, ratio brake coefficient is a setting value.

3) no interconnected branch road between bus I and the II has interconnected branch road between bus III and the II, and the accident analysis schematic diagram as shown in figure 10.

Merge into one section bus processing with bus III and bus II this moment.

The female differential current of I: $i_{\mathrm{cd}}=|-i+i_2-(i_2+\underset{j\∈(\mathrm{II}+\mathrm{III})}{\mathrm{\Σ}}{i}_j)|=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+\left|i_2\right|+|i_2+\underset{j\∈(\mathrm{II}+\mathrm{III})}{\mathrm{\Σ}}{i}_j|=\left|i\right|+2\left|i_2\right|+\left|\underset{j\∈(\mathrm{II}+\mathrm{III})}{\mathrm{\Σ}}{i}_j\right|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|i_{\mathrm{ml}1}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}1}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{|i_2-(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2)|}{\left|i_2\right|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2|}=\frac{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|}{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|+2\left|i_2\right|}$

This moment the bus-bar system operation with closed ring, female connection circulation coefficient is along with flowing out current i ₂Vary in size and change.Work as i ₂=0, little poor stalling current is constant, and female connection circulation coefficient is 1, and ratio brake coefficient is a setting value; Work as i ₂Increase, little poor stalling current increases, and female connection circulation coefficient reduces, and ratio brake coefficient reduces.

3, mode three

Female connection 3 closes, and female connection 1 disconnects, and female connection 2 closes.The operation schematic diagram as shown in figure 11.

1) no grid switching operation, mother I, mother II, the female little difference ring independence of III, the accident analysis schematic diagram is as shown in figure 12.

The female differential current of I: $i_{\mathrm{cd}}=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|i_{\mathrm{ml}1}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}1}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|}{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|}=1$

Bus-bar system open loop operation this moment, female connection circulation coefficient is 1, ratio brake coefficient is a setting value.

2) interconnected branch road is arranged between bus I and the II, no interconnected branch road between bus III and the II, the accident analysis schematic diagram is as shown in figure 13.

Merge into one section bus and handle bus I and bus II are interconnected this moment.

The female differential current of I: $i_{\mathrm{cd}}=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j-i_{\mathrm{ml}2}+i_{\mathrm{ml}3}|=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}\left|i_j\right|+\left|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j\right|+2|i_2+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|-i_{\mathrm{ml}2}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}2}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{|(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_2)-(\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2)|}{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_2|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j+i_2|}=\frac{\left|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j\right|}{\left|\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j\right|+2|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_2|}$

This moment the bus-bar system operation with closed ring, female connection circulation coefficient is along with flowing out electric current Vary in size and change.When $\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+i_2=0,$ Little poor stalling current is constant, and female connection circulation coefficient is 1, and ratio brake coefficient is a setting value; When

Increase, little poor stalling current increases, and female connection circulation coefficient reduces, and ratio brake coefficient reduces.

3) no interconnected branch road between bus I and the II has interconnected branch road between bus III and the II, and the accident analysis schematic diagram as shown in figure 14.

Merge into one section bus processing with bus III and bus II this moment.

The female differential current of I: $i_{\mathrm{cd}}=|-i-\underset{j\∈(\mathrm{II}+\mathrm{III})}{\mathrm{\Σ}}{i}_j|=|i+\underset{j\∈(\mathrm{II}+\mathrm{III})}{\mathrm{\Σ}}{i}_j|=|i+\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female stalling current of I: $i_{\mathrm{zd}}=\left|i\right|+\left|\underset{j\∈(\mathrm{II}+\mathrm{III})}{\mathrm{\Σ}}{i}_j\right|=\left|i\right|+|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|$

The female connection circulation coefficient of I:

$K_{\mathrm{hl}1}=\frac{|i_{\mathrm{ml}1}+i_{\mathrm{ml}3}|}{\left|i_{\mathrm{ml}1}\right|+\left|i_{\mathrm{ml}3}\right|}=\frac{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|}{|\underset{j\∈\mathrm{II}}{\mathrm{\Σ}}{i}_j+\underset{j\∈\mathrm{III}}{\mathrm{\Σ}}{i}_j|}=1$

Bus-bar system open loop operation this moment, female connection circulation coefficient is 1, ratio brake coefficient is a setting value.

4, implementation method

When forming cyclization when all closed formation cyclization of all female connection in the ring busbars system or because of grid switching operation; if bus generating region internal fault; because of the situation that the influence of system configuration may cause the partial fault electric current to flow out, use this moment based on mother and join the sensitivity that the bus protection ratio brake coefficient self adaptation adjustment of electric current will improve bus protection.In the cyclization operation of ring busbars system; automatically carry out the female connection of each section circulation coefficient after the big difference of bus protection starts and calculate and try to achieve the adjusted ratio brake coefficient of each section bus according to female connection circulation coefficient, whether this ratio brake coefficient differentiates a practical parameter of troubles inside the sample space as bus differential protecting.

The bus protection criterion is:

$\left\{\begin{array}{c}{i}_{\mathrm{cd}}\≥I_{\mathrm{zd}}\\ i_{\mathrm{cd}}\≥K_{\mathrm{tz}}\·i_{\mathrm{zd}}\end{array}\right.$

I wherein _CdBe differential current, i _ZdBe stalling current, I _ZdBe differential current threshold definite value.

Little poor ratio brake coefficient obtains as follows:

K _tz＝0.3+(K-0.3)·K _hl

Female connection circulation coefficient obtains as follows:

$K_{\mathrm{hl}}=\frac{|K_{\mathrm{ml}1}\·i_{\mathrm{ml}1}+K_{\mathrm{ml}2}\·i_{\mathrm{ml}2}|}{|K_{\mathrm{ml}1}\·i_{\mathrm{ml}1}|+|K_{\mathrm{ml}2}\·i_{\mathrm{ml}2}|}$

0≤K wherein _Hl≤ 1,0.3≤K _Tz≤ K.

Above data are obtained to differentiate with criterion and are all finished in real time in each sampling interval, and all based on the sampled value of each branch current of ring busbars system, the phasor that all data both can be based on same filter also can be an instantaneous sampling value to the data that are applied to.

As mentioned above, the present invention has following features and advantage:

1, a kind of bus protection ratio brake coefficient self-adapting regulation method based on the mother electric current is applicable to annular The PC bus protection of bus-bar system, method realizes relating to each branch current of ring busbars system, mother circulation Coefficient is the basis of whole method, and it is based on the electric current of two associated mothers of bus, and ratio brake coefficient Adjust and differential criterion is finished simultaneously, based on data can be branch current phasor and instantaneous value. The mother ring Following principle is followed in stream coefficient and ratio brake coefficient adjustment:

$K_{\mathrm{hl}}=\frac{|K_{\mathrm{ml}1}\·i_{\mathrm{ml}1}+K_{\mathrm{ml}2}\·i_{\mathrm{ml}2}|}{|K_{\mathrm{ml}1}\·i_{\mathrm{ml}1}|+|K_{\mathrm{ml}2}\·i_{\mathrm{ml}2}|}$

                       K _tz＝0.3+(K-0.3)·K _hl

I wherein_ml1Be the electric current of the associated mother 1 of bus, i_ml2Be the electric current of the associated mother 2 of bus, K_ml1Be the coefficient of mother 1, K when the polarity of mother 1 is consistent with bus_ml1=1, otherwise K_ml1＝-1。K _ml2Be the coefficient of mother 2, K when the polarity of mother 2 is consistent with bus_ml2=1, otherwise K_ml2＝-1，K _hlBe the mother circulation coefficient of bus, K_tzBe the ratio brake coefficient after the bus adjustment.

2, a kind of bus protection ratio brake coefficient self-adapting regulation method based on the mother electric current is at ring busbars Come into force when system's operation with closed ring and generating region internal fault, this prevents that effectively the bus protection long-time running is in low ratio Restraint coefficient state and affect the reliability of bus protection guarantees that simultaneously bus protection has when external area error Big ratio brake coefficient.

3, a kind of bus protection ratio brake coefficient self-adapting regulation method based on the mother electric current is taked each section mother Line separates the adjustment mode, and the adjustment behavior of each section bus can not produce and influence each other like this, for troubles inside the sample space and It is littler that big its ratio brake coefficient of bus of outflow electric current may be adjusted, and guarantees that effectively bus protection is reliable Fault on this bus of ground excision; Still keep higher and do not miss for its ratio brake coefficient of bus of external area error Moving.

4, a kind of bus protection ratio brake coefficient self-adapting regulation method based on the mother electric current is at ring busbars Come into force when operation with closed ring and generating region internal fault. When causing certain two sections bus interconnected operation because of grid switching operation, should The bus of interconnected operation is merged into one section bus process, associated mother should become to some extent when self adaptation was adjusted Moving, the mother electric current that the mother circulation coefficient applies to changes thereupon, and two sections buses of interconnected operation use same Ratio brake coefficient after the individual adjustment.

Claims (4)

1. A PC bus protection that is used for the ring busbars system join the adaptive method of adjustment of bus protection ratio brake coefficient of electric current based on mother, this method comprises method step:

   Based on the electric current of two associated female connection of bus, the mother who obtains bus joins circulation coefficient (K _Hl); With

   Join circulation coefficient (K based on the mother who obtains bus _Hl), (K) adjusts to previous ratio brake coefficient, obtains the adjusted ratio brake coefficient (K of self adaptation _Tz), thereby increased the reliability of PC bus protection differential criterion.
2. 2. method as claimed in claim 1, following principle is followed in wherein female connection circulation coefficient and ratio brake coefficient adjustment:

   $K_{\mathrm{hl}}=\frac{|K_{\mathrm{ml}1}\·i_{\mathrm{ml}1}+K_{\mathrm{ml}2}\·i_{\mathrm{ml}2}|}{|K_{\mathrm{ml}1}\·i_{\mathrm{ml}1}|+|K_{\mathrm{ml}2}\·i_{\mathrm{ml}2}|}$

   K _tz＝0.3+(K-0.3)·K _hl

   I wherein _Ml1Associated mother joins 1 electric current, i for bus _Ml2Associated mother joins 2 electric current, K for bus _Ml1For mother joins 1 coefficient, when mother joins 1 polarity K when consistent with bus _Ml1=1, otherwise K _Ml1=-1.K _Ml2For mother joins 2 coefficient, when mother joins 2 polarity K when consistent with bus _Ml2=1, otherwise K _Ml2=-1, K _HlFor the mother of bus joins circulation coefficient, K _TzBe the adjusted ratio brake coefficient of bus.
3. 3. method as claimed in claim 2, wherein in the formula based on data can be branch current phasor and instantaneous value.
4. 4. as the method for claim 1 or 2, wherein the PC bus protection differential criterion is:

   $\left\{\begin{array}{c}{i}_{\mathrm{cd}}\≥I_{\mathrm{zd}}\\ i_{\mathrm{cd}}\≥K_{\mathrm{tz}}\·i_{\mathrm{zd}}\end{array}\right.$

   I wherein _CdBe differential current, i _ZdBe stalling current, I _ZdBe differential current threshold definite value.

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