CN103199507A - Setting calculation extreme mode selecting method based on improved proximity set method - Google Patents

Abstract

The invention relates to a setting calculation extreme mode selecting method based on an improved proximity set method. The method includes the following steps: determining resistance values of a grounding branch circuit connected to a node where a station is located in various station modes; calculating equivalent resistance which varies from a maximum mode to a minimum mode of the station and is equivalent to the equivalent resistance of the grounding branch circuit connected to the node where the station is located; calculating effect on a fault point of the resistance when the operating mode of the station changes from the maximum to the minimum; and calculating relative change amount of the resistance of the fault point, wherein the relative change amount reflects effect on the station. The method has the advantages that according to the improved proximity set method, the station is equivalent to the grounding branch circuit, the resistance change of the branch circuit simulates the change of the station mode, the resistance change amount of the branch circuit when the station mode changes from the maximum to minimum represents the variation amplitude of the station mode, and the change of the station mode is simulated authentically. Compared with a proximity set method, the setting calculation extreme mode selecting method can delimit the influence domain of the station more accurately.

Description

A kind of based on the extreme mode system of selection of calculating of adjusting that improves next-door neighbour's collection method

Technical field

The present invention relates to technical field of power systems, particularly a kind of based on the extreme mode system of selection of calculating of adjusting that improves next-door neighbour's collection method.

Background technology

Determine that power system operation mode is the prerequisite that relay protection setting calculates.In the practical operation of electric power system, the definite value of deciding can not frequently be changed, thus definite value need can adaptive system various operational modes.

In electric power system, the content calculated of adjusting comprise to different fault points (for example on the circuit any point, terminal bus, successive relay trip namely in the three-phase tripping operation of circuit end switch elder generation but the situation that the fault point still exists), different fault type (single-phase earthing, two phase ground, line to line fault, three-phase shortcircuit) carries out various combinations calculating with different operational modes (for example excising power system component such as generator, circuit, transformer) and compares, to determine extreme operational mode and setting value.Extreme operational mode, namely protection is the most difficult in system's operational mode that may occur satisfies that sensitivity requires or satisfies the operational mode that selectivity requires with adjacent protection is the most difficult.Choose extreme operational mode from the possible operational mode of system, protection then can guarantee the correctness that protection was moved when system operation mode changed by satisfying sensitivity and selectivity requirements adjusted under these modes.Therefore, in the computational process of adjusting, the definite value that obtain holding water need be considered various possible operational modes, and obtains corresponding calculated value under these operational modes, thereby picks out extreme operational mode and setting value.

But along with the expansion of electric power system scale and the continuous variation of electric network composition, the operational mode of electric power system becomes more and more, all possible power system operation mode is carried out setting value calculate problems such as having amount of calculation is big, elapsed time length.How selecting representative system operation mode to carry out setting value calculating and guarantee that the result is appropriately reasonable fast from the system operation mode of complexity, is the new task that relay protection setting value calculating personnel and relay protection setting value computation software authorized personnel face.

Existing traditional Operation Mode Selection method is only considered few operational mode, and consideration is too simple like this, and the definite value that obtains is not quite reliable, also exists certain irrationality.As by rationally programming, allow computer that all possible operational mode is made up out, therefrom select the operational mode that needs again, so not only the efficient of adjusting can be improved greatly, and the service behaviour of protective device can be improved.If but sequential logic method of thinking routinely carries out step-by-step calculating, various situation combinations will be extremely various, and amount of calculation is very huge, and computing time will be long, and can reduce computing capability and the practicality of setting procedure greatly.But; consider that all possible operational mode of the whole network is too in complexity; in order accurately and effectively to determine the extreme operational mode that protection is adjusted; need be on a large scale, selectively consider that network topology structure changes the influence to fault current and protection definite value; the number that the minimizing mode makes up; reduce calculation times, thereby shorten computing time.

Summary of the invention

Technical problem to be solved by this invention provides a kind of based on the extreme mode system of selection of calculating of adjusting that improves next-door neighbour's collection method.

For solving the problems of the technologies described above, the present invention realizes as follows: a kind of based on the extreme mode system of selection of calculating of adjusting that improves next-door neighbour's collection method, may further comprise the steps:

Determine to be connected under each factory's station mode the ground connection branch impedance value of place, factory station node;

Calculate equivalent impedance, described equivalent impedance is that described factory station is changed to minimum mode from maximum mode, is equivalent to the ground connection branch road that has inserted described equivalent impedance at place, factory station node;

Calculate factory's station operational mode and become hour influence to the fault point self-impedance by maximum;

Calculate the relative variation of fault point self-impedance, as the size of described factory station influence.

Good effect of the present invention is: improving next-door neighbour's collection method is a ground connection branch road with factory's equivalence of standing, change in this branch impedance change modeling factory station mode, and represent factory's station mode amplitude of variation in factory station mode by the branch impedance variable quantity that maximum becomes hour, real simulation the mode at factory station change.Compare with next-door neighbour's collection method, this method can be delimited factory's station domain of influence more accurately.

Description of drawings

Fig. 1 is the equivalent key diagram of single system in the prior art;

Fig. 2 is the equivalent impedance of different factories station mode correspondence

Fig. 3 changes the modification of counterpart impedance for factory's station mode

Embodiment

One, the basic process of tradition next-door neighbour collection method:

Define a kind of electric amount that goes up degree of closeness mutually of representing between node, be referred to as degree of next-door neighbour, the set that meets degree of next-door neighbour and be the node of standard is referred to as to be close to set of node.With the foundation of internodal next-door neighbour's degree as definite participation operational mode composition element scope, think that namely the element change on the node that only falls into next-door neighbour's set of node is only topmost to the influence of short circuit current, the variation of the element on other node can not considered, i.e. not participation method combination yet.

In the middle of system, the changes of operating modes at factory station mainly is reflected in the variation of its node equivalence earth impedance.Therefore, only need to change the equivalent earth impedance Cjj of node J, just can simulate the variation of factory's station operational mode preferably.When the operational mode that changes the factory station, namely when the equivalent earth impedance of J node was changed to p * Cjj, the self-impedance of fault point was changed to Relkj * Zkk.Because the size of the fault current of fault point is subjected to the influence of self-impedance very big, so the variation multiple Relkj of self-impedance can reflect J point changes of operating modes preferably to the influence of K point failure electric current, Relkj is degree of next-door neighbour just.

Be node with the factory station, circuit is branch road, each factory's station predefine maximum, minimum operational mode.Retention fault node K and the tiny node J of factory carry out equivalence with network, and equivalent network as shown in Figure 1.

Wherein the meaning of each parameter is as follows:

Ckj---the equiva lent impedance of electrical distance between reaction K-J;

Ckk---fault point equivalence earth impedance;

Cjj---J node equivalence earth impedance.

Nodal impedance matrix element Zkk, Zkj, Zjj and Ckk, Ckj, Cjj have relation as follows:

Zkk＝Ckk||(Ckj+Cjj) (1)

Zkj＝Ckk×Cjj/(Ckk+Ckj+Cjj) (2)

Zjj＝Cjj||(Ckj+Ckk) (3)

When factory's station operational mode changed, fault point self-impedance Zkk had changed Relkj doubly when namely the equivalent earth impedance Cjj of node J changed p times, then had:

Relkj×Zkk＝Ckk(Ckj+p×Cjj)/(Ckk+Ckj+p×Cjj)

(4)

${\mathrm{Rel}}_{\mathrm{kj}}=\frac{C_{\mathrm{kk}}+C_{\mathrm{kj}}+C_{\mathrm{jj}}}{C_{\mathrm{kk}}+C_{\mathrm{kj}}+p\×C_{\mathrm{jj}}}\×\frac{C_{\mathrm{kj}}+p\×C_{\mathrm{jj}}}{C_{\mathrm{kj}}+C_{\mathrm{jj}}}---\left(5\right)$

(1), (2), (3) are got through substitution (5) after the conversion:

${\mathrm{Rel}}_{\mathrm{kj}}=\frac{(Z_{\mathrm{kk}}-Z_{\mathrm{kj}})/(Z_{\mathrm{jj}}-Z_{\mathrm{kj}})+Z_{\mathrm{kk}}/Z_{\mathrm{kj}}}{(Z_{\mathrm{kk}}-Z_{\mathrm{kj}})/(Z_{\mathrm{jj}}-Z_{\mathrm{kj}})+Z_{\mathrm{kk}}/Z_{\mathrm{kj}}-1+p}\×\frac{Z_{\mathrm{kk}}/Z_{\mathrm{kj}}-1+p}{Z_{\mathrm{kk}}/Z_{\mathrm{kj}}}---\left(6\right)$

The formula that obtains (6) is exactly next-door neighbour's degree that the J point is ordered to K.Can suppose that when p=10 it is less that 0.9≤q≤1.1 (q=Relkj) illustrates that then self-impedance that K orders changes, short circuit current changes little, judges that the influence that the J point orders to K is very little, does not also namely enter next-door neighbour's set of node; Otherwise then enter next-door neighbour's set of node.Above-mentioned criterion algorithm is simple, only need utilize the impedance matrix coherent element of primitive network to get final product.

Two, the present invention is further detailed explanation below in conjunction with the drawings and specific embodiments.

Of the present invention a kind of based on the extreme mode system of selection of calculating of adjusting that improves next-door neighbour's collection method, done corresponding improvement at tradition next-door neighbour collection method, its basic ideas are as follows: each factory station all is equivalent to a ground connection branch road that is connected place, factory station node, represents that with its impedance variation the mode at factory station changes; Determine corresponding ground connection branch impedance value under each factory's station different modes, represent the amplitude of variation of this factory's station mode with the maximum impedance value to the amplitude of variation of minimum impedance value.

Step 1, determine to be connected under each factory's station mode the resistance value of place, factory station node J ground connection branch road, suppose that counterpart impedance is Zj under factory's station maximum mode, counterpart impedance is Zj ' under the minimum mode, as shown in Figure 2.

Step 2, factory station are changed to minimum mode from maximum mode, are equivalent at place, factory station node and have inserted a ground connection branch road that impedance is Δ Zj, as shown in Figure 3.

Step 3, factory station operational mode by the influence that maximum becomes hour the fault point self-impedance is:

$Z_{\mathrm{kk}}^{\′}=Z_{\mathrm{kk}}-\frac{Z_{\mathrm{kj}}^2}{Z_{\mathrm{jj}}+{\mathrm{\ΔZ}}_j}---\left(7\right)$

The relative variation of step 4, fault point self-impedance is:

$\mathrm{\δ}=\frac{Z_{\mathrm{kj}}^2}{(Z_{\mathrm{jj}}+{\mathrm{\ΔZ}}_j)\·Z_{\mathrm{kk}}}---\left(8\right)$

Following formula is and improves the computing formula that the next-door neighbour Ji Fachang station domain of influence delimited index.

From said process as can be seen, improving next-door neighbour's collection method is a ground connection branch road with factory's equivalence of standing, change in this branch impedance change modeling factory station mode, and represent factory's station mode amplitude of variation in factory station mode by the branch impedance variable quantity that maximum becomes hour, real simulation the mode at factory station change.Compare with next-door neighbour's collection method, this method can be delimited factory's station domain of influence more accurately.

The circuit changes of operating modes all will exert an influence to impedance matrix positive sequence and zero sequence element, zero-sequence mutual inductance branch road particularly, its stoppage in transit can not simply be represented with adding the negative impedance branch road, therefore, if still adopt impedance matrix as discriminant criterion, to produce the excessive problem of amount of calculation, can not guarantee the rapidity that the domain of influence delimited.

Three, process delimited in the line influence territory of improving next-door neighbour's collection method

Based on existing line domain of influence delimitation method, subgraph decomposition and loop search technique based on graph theory have provided some basic principles of delimiting the line influence territory below:

(1) adjust the protection and mating protection two ends bus on connection line delimit in the line influence territory.

(2) cut-off some weak circuits of contact in the electric power networks; it is divided into the subgraph of several connections; the domain of influence of protection circuit is only considered the influence of the weak line mode variation that circuit links to each other with this subgraph in the same subgraph in each subgraph, does not consider the influence that line mode changes in other subgraphs.

(3) determine to comprise the loop number of protection place circuit and constitute the circuit in loop with protection place circuit.If after disconnecting a certain circuit, comprising protection loop decreased number must be more many, and then this line mode changes to the protection influence more greatly, and then this circuit should be delimited in the line influence territory.

(4) be total to end line for many times both-ends, if its parameter is inconsistent, only need impedance the maximum is delimited in the line influence territory; If the parameter unanimity then selects a circuit to delimit in the line influence territory arbitrarily.

Claims (5)

1. the extreme mode system of selection of calculating of adjusting based on improvement next-door neighbour collection method is characterized in that, may further comprise the steps:

Determine to be connected under each factory's station mode the ground connection branch impedance value of place, factory station node;

Calculate equivalent impedance, described equivalent impedance is that described factory station is changed to minimum mode from maximum mode, is equivalent to the ground connection branch road that has inserted described equivalent impedance at place, factory station node;

Calculate factory's station operational mode and become hour influence to the fault point self-impedance by maximum;

Calculate the relative variation of fault point self-impedance, as the size of described factory station influence.

2. according to claim 1 a kind of based on the extreme mode system of selection of calculating of adjusting that improves next-door neighbour's collection method, it is characterized in that: the ground connection branch impedance value that is connected in place, factory station node under described definite each factory's station mode specifically comprises:

Determine that counterpart impedance is Zj under factory's station maximum mode, counterpart impedance is Zj ' under the minimum mode.

3. according to claim 1 a kind of based on the extreme mode system of selection of calculating of adjusting that improves next-door neighbour's collection method, it is characterized in that: described calculating equivalent impedance specifically is to calculate according to following formula:

${\mathrm{\Δ}Z}_j=\frac{Z_j{Z}_j^{\′}}{Z_j^{\′}-Z_j}.$

4. according to claim 1ly a kind ofly calculate extreme mode system of selection based on improving adjusting of next-door neighbour's collection method, it is characterized in that: described calculating factory station operational mode specifically is to calculate according to following formula by the influence that maximum becomes hour the fault point self-impedance:

$Z_{\mathrm{kk}}^{\′}=Z_{\mathrm{kk}}-\frac{Z_{\mathrm{kj}}^2}{Z_{\mathrm{jj}}+\mathrm{\Δ}{Z}_j}.$

5. according to claim 1 a kind of based on the extreme mode system of selection of calculating of adjusting that improves next-door neighbour's collection method, it is characterized in that: the relative variation of described calculating fault point self-impedance, the size that influences as described factory station specifically is to calculate according to following formula:

$\mathrm{\δ}=\frac{Z_{\mathrm{kj}}^2}{(Z_{\mathrm{jj}}+{\mathrm{\ΔZ}}_j)\·Z_{\mathrm{kk}}}.$

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