WO2018040803A1

WO2018040803A1 - Direct calculation method based on ring network power system

Info

Publication number: WO2018040803A1
Application number: PCT/CN2017/094287
Authority: WO
Inventors: 邓宏伟; 邓朝尹
Original assignee: 邓宏伟
Priority date: 2016-08-30
Filing date: 2017-07-25
Publication date: 2018-03-08
Also published as: CN106451456B; CN106451456A

Abstract

Disclosed is a direct calculation method based on a ring network power system. The method mainly solves problems of great error in a calculation result, no convergence and low calculation speed, etc. of an iteration method applied in an existing power flow algorithm. In the direct calculation method, a specific method for calculating an overall matrix of the entire power system network is as follows: (11) calculating matrices of various nodes; and (12) according to a connection sequence of the various nodes, multiplying the matrices of the various nodes in sequence to obtain an overall matrix of a power system network, wherein the nodes comprise: a basic node constituted by a single element, a chain-type node corresponding to a chain constituted by several basic nodes, a basic ring network node corresponding to a basic ring network constituted by several chain-type nodes, and a combined ring network node corresponding to a combined ring network constituted by several basic ring network nodes and chain-type nodes by means of sheathed connection.

Description

A direct calculation method based on ring network power system

Technical field

The invention relates to the field of power flow calculation of a power system, and in particular to a direct calculation method of a power system with a ring network.

Background technique

Power system power flow calculation is a basic electrical calculation for studying the steady state operation of power systems. Its mission is to determine the operating state of the entire system based on given operating conditions and network structure, such as voltage (amplitude and phase angle) on each bus, power distribution in the network, and power loss. The result of power system power flow calculation is the basis of power system stability calculation and fault analysis. In the prior art, the power system power flow calculation method generally adopts an iterative method, also called a twisting method, which is a process of continuously retrieving new values by using the old values of variables, which uses a computer to calculate fast and is suitable for repeatability. The characteristics of the operation, let the computer repeat the execution of a set of instructions (or certain steps), each time the group of instructions (or these steps) is executed, it pushes out a new value from the original value of the variable, the most common iteration The law is Newton's law. The drawback of the iterative method is that it needs to constantly recurs the new value with the old value of the variable, and the final calculation result has large error and low precision. Secondly, the iterative method is continuously recursed in the operation process, when the value used is wrong. Then, the value needs to be re-selected and then calculated. The operation speed is slow, and the operation result does not converge. The operation principle is shown in Figure 1. In addition, the applicability of the iterative method is not strong, especially for large networks. And different power system networks need to be iterated in different ways. In the prior art, the power flow calculation of the power system ring network has defects such as large error, slow calculation speed, and sometimes no convergence.

Summary of the invention

The object of the present invention is to overcome the above drawbacks and to provide a power flow direct calculation method for a power system with accurate calculation results and fast calculation speed.

Explanation of terms used in the application of the present invention:

In the application of the present invention, the smallest unit is an element, and the basic node is composed of a single element;

Chain: Several elements are connected in sequence to form a chain. The chain includes a word chain and a branch chain. Among them, a word chain: as shown in Fig. 8, except for the first node, the head end of the other node is connected to the end A of the previous node. The resulting network is a chain of words.

Branch: As shown in Figure 9, if the head end of a node is connected to the end B of the previous node, and the node and subsequent nodes form a word chain, then the word chain formed from the node is a branch; The chain can be socketed.

As shown in Figure 9, node 10 and node 11 form a branch; node 12 forms a branch; node 13 and node 14 form a branch; node 15 forms a branch;

node

16 and 17 The nodes form a branch.

Ring network (also known as combined ring network): It consists of several basic ring networks and chain combinations.

The basic ring network: word ring network, day ring network, field word ring network, mesh ring network, etc., the basic ring network refers to only the chain, but without the rest of the ring network.

Among them, the word ring network consists of two chains, the Japanese word ring network consists of five chains, the field word ring network consists of eight chains, and the word word ring network consists of eight chains. In the application of the present invention, a word ring network, a Japanese word ring network, a mesh ring network, and a field word ring network are defined as a basic ring network. The chain in the ring network is also called the ring side or the side.

The intermediate point of the ring network refers to the boundary point between the edge and the edge of the ring network (except the starting and ending point of the ring network), and the voltage is called the intermediate point voltage of the ring network.

As shown in the following figure, the ring network consists of a ring network node, a ring network end node, and a ring network edge.

The intermediate point of the ring network refers to the boundary point between the edge and the edge of the ring network (except the starting and ending points of the ring network), and the voltage is called the intermediate point voltage of the ring network or the intermediate voltage of the ring network.

As shown in Figure 10, node 102 is the starting node of the small-mouth ring network, node 103 is the end node of the small-mouth ring network; node 33 and node 34 form an edge of the small-mouth ring network, node 35 and Node 36 forms the other side of the small mouth ring network.

Node 101 is the starting point of the Japanese word ring network, node 31 is the end point of the Japanese word ring network, node 21, node 22, node 24, node 25 form the four sides of the Japanese word ring network, node 23 The No. 27 node, the No. 28 node, the No. 29 node, the No. 30 node, and the No. 26 node form the fifth side of the Japanese word ring network, and the B point and the C point are the intermediate points of the Japanese word ring network.

Node 3 is the starting point of the big mouth ring network, and the end point of the big mouth word ring network of the 14th node; No. 4, (6, 7), 5, (9, 10), 8 and 11, ( No. 13 and No. 12 form one side of the big mouth ring network, the Japanese word ring network, the 31st node, the (small mouth word ring network), and the 32nd node form the other side of the big mouth ring network.

The power system network is composed of a node (component), a chain, a basic ring network, and a combined ring network.

The transmission parameter matrix, also called the T parameter matrix, takes a node A as an example, and its expression is as follows:

or

Wherein, U _{1, A} represents the starting voltage of node A, I _{1, A} represents the starting current of node A, U _{2, A} represents the terminal voltage of node A, I _{2, and A} represents the terminal current of node A;

According to the equations

Available

make

Thus, [A'] or

An admittance parameter matrix or admittance matrix or a Y-parameter matrix called node A; conversely, according to the equations

Available

make

Can be restored to node A's transmission parameter matrix or transmission matrix or T-parameter matrix

For a chain, the transmission parameter matrix is equal to the multiplication of the transmission parameter matrix of the component in the chain connection order according to the component connection order;

The above is the mutual conversion method between the transmission parameter matrix and the admittance parameter matrix. In the present application, f([X]) represents converting a T parameter matrix of a certain component or chain into a Y parameter matrix, g([ X]) is to convert the Y parameter matrix of a component or chain into a T parameter matrix.

Note: The numbers in Figures 7-10 represent the node number or node number.

In order to achieve the above object, the present invention adopts the following technical solutions:

A power flow direct calculation method for a power system includes the following steps:

(1) Calculate the total matrix of the entire power system network:

(2) Substituting the total matrix of the power system network into the following formula:

(3) Calculate the starting voltage of the power system network

And the starting current I _{starts to} =0;

(4) According to the following formula, the terminal voltage U _2,d and the terminal current I _{2,d of} each component are sequentially calculated according to the connection order of the components:

Wherein, according to the connection order of the components, the terminal voltage and the terminal current of the previous component are the starting voltage and the starting current of the latter component;

(5) Calculate the operating voltage, operating current and power loss of the component according to the calculated starting voltage, starting current, terminal voltage and terminal current of the component;

Wherein; is _from the borders of the U-voltage of the power system network, U is _{the end of} the terminal voltage of the electric power system network, the I current _from the borders of a power system network, which is equal to 0, I is the tail current _{at the end} of a power system network, which The value is equal to 0, [W _total ] represents the total matrix of the power system network, [A _d ] represents the matrix of a component, U _1,d represents the starting voltage of the component, and I _1,d represents the starting current of the component, U _{2 , d} represents the terminal voltage of the component, and I _2,d represents the terminal current of the component;

The specific manner of the step (1) is as follows:

(11) Calculating the matrix of each node;

(12) sequentially multiplying the matrix of each node according to the connection order of each node to obtain a total matrix of the power system network;

The node includes: a basic node composed of a single component, a chain node corresponding to a chain composed of a plurality of basic nodes, a basic ring network node corresponding to a basic ring network composed of a plurality of chain nodes, and a plurality of basic ring network nodes, a combined ring network node corresponding to the combined ring network formed by the chain node socket;

Wherein, the matrix of the basic node is a matrix of components, the matrix of the chain nodes is equal to the matrix of each component in the chain, and the matrix of the basic ring network is obtained by combining the matrix of the constructed chain nodes, the ring network The matrix of the nodes is obtained by combining the formed chain nodes and the matrix of the basic ring network nodes;

The component includes any one or more of a generator, a load, a transformer, and a line. Correspondingly, the matrix of the generator is

The matrix of the load is

The concentrated parameter matrix of the line is

And distributed parameter model matrix

The matrix of the transformer is

Where E is the ideal voltage of the generator, r is the internal impedance of the generator, Y is the admittance of the load, Z is the impedance of the line, n ₁ and n ₂ are the number of turns of the primary side of the transformer, respectively. Parametric model matrix

Time

among them:

The basic ring network is a combined matrix calculation method for a spoken word ring network as follows:

First, calculate the transmission parameter matrix of the A- _port chain and the B- _port chain in the word-ring ring network:

with

Wherein, the transmission parameter matrix of each chain is equal to the matrix of all components in the chain, which are sequentially obtained according to the connection order of the components;

Secondly, convert [A _port ] and [B _port ] into corresponding admittance parameter matrices: [A _port '] and [B _port '];

Second, add [A _port '] and [B _port '] according to the following formula:

Finally, the calculation result of [ _A'port ]+[ _B'port ] is converted into a transmission parameter matrix, which is the merge matrix of the word ring network.

The basic ring network is calculated as a merge matrix of the Japanese word ring network as follows:

First, calculate the transmission parameter matrix of the A- _day chain, the B- _day chain, the C- _day chain, the D- _day chain, and the E- _day chain in the Japanese word ring network:

After solving, the admittance parameter matrix of the Japanese word ring network can be obtained:

And the intermediate point voltage as a function of the starting voltage and terminal voltage of the Japanese word ring network

Finally, the calculated admittance parameter matrix:

Converted to a transmission parameter matrix, which is the merge matrix of the Japanese word ring network.

The basic ring network is a consolidation matrix calculation method of the field word ring network as follows:

First, calculate the transmission parameter matrix of the A _field chain, the B _field chain, the C _field chain, the D _field chain, the E _field chain, the F _field chain, the G _field chain, and the H _field chain in the Tianzi ring network:

Then, calculate the admittance parameter matrix of the field word ring network

And the intermediate point voltage as a function of the starting voltage and terminal voltage of the field ring network

Finally, the calculated admittance parameter matrix:

Converted to a transmission parameter matrix, which is the merge matrix of the field word ring network;

In the formula, U _{Tian a} , U _{Tian b,} and U _{Tian c} represent the intermediate voltage of the Tianzi ring network.

The basic ring network is calculated as a merge matrix of the mesh ring network as follows:

Firstly, calculate the transmission parameter matrix of the A _mesh chain, the B _mesh chain, the C _mesh chain, the D _mesh chain, the E _mesh chain, the F _mesh chain, the G _mesh chain, and the H _mesh chain in the target ring network:

Then, calculate the admittance parameter matrix of the mesh of the mesh

And the intermediate point voltage as a function of the starting voltage and terminal voltage of the ring

Finally, the calculated admittance parameter matrix:

Converted to a transmission parameter matrix, which is the merge matrix of the target ring network;

In the formula, U _{mesh a} , U _{mesh b} , U _{mesh c,} and U _{mesh d} represent the intermediate voltage of the mesh ring.

The calculation method of components in the basic ring network is as follows:

(a) calculating the terminal voltage and terminal current of the basic ring network based on the starting voltage of the basic ring network and the starting current and the combined matrix of the basic ring network;

(b) Calculate the basic voltage of the basic ring network based on the relationship between the starting voltage and the terminal voltage of the basic ring network and the intermediate voltage of the basic ring network and the starting voltage and the terminal voltage of the ring; thus knowing the sides (chains) of the basic ring network Starting voltage and terminal voltage;

(c) calculating the starting current of each side (chain) according to the starting voltage and the terminal voltage of each side (chain) of the basic ring network and the matrix of each side (chain);

(d) According to the following formula, the terminal voltage U _2,d and the terminal current I _2,d of each component are sequentially calculated according to the connection order of the components in the chain;

Wherein, according to the connection order of the components in the chain, the terminal voltage and the terminal current of the previous component are the starting voltage and the starting current of the latter component; U _1,d represents the starting voltage, and I _1,d represents the starting current. [A _d ] represents the transmission matrix of a node in a chain in the ring network.

In the step (1), if a branch is encountered, the total matrix of the power system network is obtained by multiplying the transformation matrix of the branch with the matrix of the remaining components according to the connection order relationship between the branch and the remaining components; The transformed transformation matrix is obtained by transforming the transmission parameter matrix obtained by multiplying the matrices of all components on the branch.

The calculation method of the parameters of each component in the branch:

First, calculate the starting voltage and starting current of the branch;

Secondly, the terminal voltage and the terminal current of each component are sequentially calculated according to the connection order of the components in the branch; wherein, according to the connection order of the components in the chain, the terminal voltage and the terminal current of the previous component are the starting points of the latter component. Voltage and starting current; (calculated according to the calculation method of the branch in the "straight algorithm of one-word chain and branched three-phase symmetric multi-supply non-ring power system").

Finally, based on the calculated starting voltage, starting current and terminal voltage, and terminal current of the component, the operating voltage, operating current, and power loss of the component can be calculated.

The design idea of the invention is: taking the ring network as a node, converting the power system network with the ring network into a word-chain network, calculating the merge matrix of the ring network according to the ring network type, and using the merged matrix as the ring network Transmitting a parameter matrix (or a T-parameter matrix), in the chain of words in which the ring network is located, multiplying the transmission parameter matrix of the ring network with the transmission parameter matrix of the remaining components in the chain according to the connection order to obtain the third-order total of the chain The matrix is then calculated for power flow according to a straight algorithm.

Compared with the prior art, the beneficial effects of the present invention are:

The power system network of the present invention is constructed as a plurality of nodes, and then sequentially calculated according to the nodes, thereby directly calculating the starting voltage and current of the power system network, and the value thereof is an accurate value, and then according to the starting point of the power network. Voltage and current, in turn calculate the starting voltage, current, terminal voltage, current, power loss and other parameters of each node. The invention avoids the calculation method of the new value recursive value of the variable used by the iterative method of the prior application, the calculation result is accurate, no error, the calculation speed is faster, the time is shorter, especially for the line model invention The distributed parameter model is adopted, which can be applied to a variety of power networks, especially for large networks and complex networks.

DRAWINGS

Figure 1 is a schematic diagram of an iterative method.

Figure 2 is a general schematic diagram of the circuit of the present invention.

Figure 3 is a schematic diagram of the distribution parameters of the line in the present invention

Figure 4 is a schematic diagram of the load in the present invention.

Figure 5 is a schematic diagram of a transformer in the present invention.

Figure 6 is a schematic diagram of a generator of the present invention.

Figure 7 is a schematic diagram 1 of a power system network.

Figure 8 is a schematic diagram 2 of a power system network.

Figure 9 is a schematic diagram 3 of a power system network.

Figure 10 is a schematic diagram 4 of a power system network.

Figure 11 is a schematic diagram of a Japanese word ring network.

Figure 12 is a schematic diagram of a field ring network.

Figure 13 is a schematic diagram of a mesh ring.

Figure 14 is a schematic diagram of a word ring network.

detailed description

The invention will now be further described with reference to the accompanying drawings. Embodiments of the invention include, but are not limited to, the following examples.

Example 1

In this embodiment, the components in the power network are first described with reference to the accompanying drawings:

As shown in Figure 2, the general principle for the line:

according to

then

As shown in Figure 3, the principle of the distribution parameters for the line:

according to

then

As shown in Figure 4, for the load:

according to

Got

then

I represents the load operating current

As shown in Figure 5, for the transformer:

Transformers and transformers take the double-turn transformer as an example. When three-turn transformers are involved, they can also be used as three double-turn transformers. Calculate:

according to

Got

then

In practical applications, the actual double-turn transformer can be used as a load, a line and an ideal double-turn transformer, and the corresponding matrix can be obtained by multiplying the matrix of the load, the line and the ideal transformer.

As shown in Figure 6, for the generator:

according to

Got

then

When calculating the matrix of the generator, the theoretical basis of the matrix is: the generator is equivalent to the series connection of the ideal voltage E and the internal resistance r.

In this embodiment, the positive direction of the current in the power system network is from left to right and top to bottom. The ring network and its two links are taken as examples to illustrate the calculation of the ring network:

First, the word ring network

For word of mouth rings, 14, word of mouth ring network which is constituted by two sides (chains): _port A and _port B chain strand, on each edge (strand) each member comprising: edge (strand) There is at least one transformer or one line in the main chain. The former chain of the word ring network is the R chain, and the latter chain is the S chain. The R chain and the S chain are connected by a plurality of elements in sequence. The elements in the R chain and the S chain may be formed in the same order or in the same order. Similarly, multiplying the transmission parameter matrices of these components yields the total matrix [R] of the R chain and the total matrix [S] of the S chain. The calculation method of the merge matrix (transmission parameter matrix) of the spoken word ring network is as follows:

In order to facilitate the viewing and understanding of the formula, in the calculation of the word ring network, U _{1, A port} represents the starting voltage of the A _port chain, and I _{1, A port} represents the starting current of the A _port chain. U _{2, A} represents a terminal voltage of the A _port _mouth _chain, I _{2, A} represents a terminal _port _opening current A chain. U _{1, B port} indicates the starting voltage of the B _port chain, and I _{1, B port} indicates the starting current of the B _port chain. U _{2, port B} represents the terminal voltage of the B _port chain, I _{2 , and port} B represents the terminal current of the B _port chain.

As you can see

According to the mutual conversion method between the transmission parameter matrix and the admittance parameter matrix

Also, since U _{1, A port} = U _{1, B port} = U ₁ is the starting voltage of the mouth word ring network, U _{2, A port} = U _{2, B port} = U ₂ is the terminal voltage of the mouth word ring network, so

which is

Also due to

I _{2, R} is the terminal current of the R chain, I _{1, S} is the starting current of the S chain, and since I _{2, R} is equal to the starting current of the ring net, I _{1, S} is equal to the terminal current of the ring net, so

Therefore, in this particular environment, the following matrix addition calculation method is defined:

The merge matrix of the word ring network [Q _port ]=g(f([A _port ])+f[B _port ])), the T parameter matrix of a certain component or chain is represented by the aforementioned f([X]) Convert to a Y parameter matrix. Therefore, f ([A _port]) for the overall matrix _port A chain (transmission parameter matrix) [A _port] is expressed as [A by admittance matrix parameters conversion method between the transmission parameters of the admittance matrix of the parameter matrix obtained _Port '], f ([B _port ]) is the total matrix of the B- _port chain (transmission parameter matrix) [B- _port ] The admittance parameter matrix obtained by the mutual conversion method between the transmission parameter matrix and the admittance parameter matrix is expressed as [B _port '], that is, [Q _port ]=g(f([A _port ])+f[B _port ]))=g([A' _口 ]+[B' _口 ]), [A' _口 ] +[ _B'port ] is calculated according to the matrix addition method defined above:

From the aforementioned g([X]) is to convert the Y parameter matrix of a certain element or chain into a T parameter matrix. Therefore, g ([A' _port ]) + [B' _port ]) is converted to obtain the corresponding T parameter matrix [Q _port ].

After the calculation of the merged matrix of the word ring network is completed, the total matrix of the merged matrix of the R chain and the spoken word ring network and the total matrix of the S chain are sequentially multiplied to obtain the total matrix of the entire network:

[W]=[R]·[Q _port ]·[S]=[R]·g(f([A _口 ])+f([B _口 ]))·[S]

Substituting the total matrix [W] into the following formula:

Wherein, U is _from the borders of a power system network voltage, U is _{the end of} the terminal voltage of the electric power system network, the I current _from the borders of a power system network, which is equal to 0, I is the tail current _{at the end} of a power system network, which The value is equal to zero.

then

Then the starting voltage of the power system network consisting of the R chain, the word ring network and the S chain

I _from 0;

Then, according to the starting voltage of the power system network

And the starting current I _from 0 can calculate the R chain, the word ring network, the starting voltage of the S chain, the starting current, the terminal voltage, and the terminal current. In R the chain, ring opening words, the power network system S chains, a starting end voltage Qiduan R chain is a voltage U _from the electric power system network, the base end of the chain R Qiduan current zero current electric power system network The end voltage of the S chain is equal to the terminal voltage of the power system network, and its terminal current is equal to the end current of the power system, and its value is equal to zero.

For the word ring network, the starting voltage and the starting current are equal to the end voltage of the R chain and the terminal current; the terminal voltage and the terminal current are equal to the starting voltage of the S chain and the starting current.

Then, for the R chain and the S chain, the two can be regarded as a one-word chain power system. If the component to be calculated is in one of the two chains, then the chain and the branch can be The chain-type three-phase symmetric multi-supply non-ring network power system straight algorithm (the algorithm is disclosed in the prior art, patent number: 201410142938.7) completes the calculation, and the following is an example in which the component to be calculated is located in the R chain:

First, according to the above calculation, the starting voltage and the starting current of the R chain are known; the total matrix of the R chain is the elements in the chain. The matrix of the pieces is obtained by multiplying in order of connection;

According to the position of the component to be calculated in the R chain, the terminal voltage U _2,d-1 and the terminal current I _2,d-1 of the previous component are calculated and used as the starting voltage U _{1,d of the} component to be calculated _. =U _2,d-1 and the starting current I _1,d =I _2,d-1 ;

Then, according to the formula:

Calculate the terminal voltage U _2,d and the terminal current I _{2,d of the} component to be calculated. Under the premise that the starting voltage, the starting current, the terminal voltage and the terminal current of the component to be calculated have been determined, the calculation can be calculated. Calculate the operating voltage, operating current and power loss of the component, and complete the calculation of the component to be calculated; where [A _d ] ^-1 represents the inverse matrix of the component to be calculated, and U _1,d represents the starting voltage of the component to be calculated, I _{1, d} represents the starting current of the component to be calculated, U _2,d represents the terminal voltage of the component to be calculated, and I _2,d represents the terminal current of the component to be calculated.

If the component to be calculated is located in the word ring network, according to the foregoing calculation, the starting voltage U _1,Q and the starting current I _1,Q of the word ring network are known;

by

Where: [Q _port ] ^-1 is the inverse matrix of the total matrix of the word ring network

Can calculate the terminal voltage U _{2,Q of the} exit word ring network, the terminal current I _2,Q

by

The starting current of the A- _port chain I _{1, A} can be calculated

Same reason

The starting current I _{1, B} of the B- _port chain can be calculated _.

As the element to be calculated and the borders of the borders of the current and the voltage to be calculated when the elements in the A-chain _port, the position of elements in the A chain is calculated _opening, which is calculated before the terminal voltage and terminal current of one element to be in accordance with .

Then, according to the formula:

Calculate the terminal voltage U _2,d and the terminal current I _{2,d of the} component to be calculated. Under the premise that the starting voltage, current, terminal voltage and current of the component to be calculated have been determined, the component to be calculated can be calculated. Operating voltage, operating current, and power loss, completing the calculation of the component to be calculated; where [A _d ] ^-1 represents the inverse matrix of the component to be calculated, U _1,d represents the starting voltage of the component to be calculated, I _1,d Represents the starting current of the component to be calculated, U _2,d represents the terminal voltage of the component to be calculated, and I _2,d represents the terminal current of the component to be calculated.

Second, the Japanese word ring network

As shown in Figure 11, for the Japanese word ring network (also known as the 8-word ring network), it consists of five sides (chain): A _day chain, B _day chain, C _day chain, D _day chain, E _day chain, each The strip (chain) includes components: at least one transformer or one line in the main chain of the side (chain).

The former chain of the Japanese word ring network is the R chain, and the latter chain is the S chain. The R chain and the S chain are each connected by a plurality of elements in sequence. The elements in the R chain and the S chain may be formed in the same order or in the same order. Similarly, multiplying the transmission parameter matrices of these components yields the total matrix [R] of the R chain and the total matrix [S] of the S chain. The calculation method of the merging matrix (transmission parameter matrix) for the Japanese word ring network is as follows:

Step 1 Determine the start and end points of the ring and their voltage points

U ₁ is the starting voltage of the Japanese word ring network, and U ₂ is the terminal voltage of the Japanese word ring network.

Step 2 Determine the intermediate point of the ring network and its voltage

The boundary point between the edge and the edge of the ring network is defined as the intermediate point of the ring network (except the starting point and the end point of the ring network), and the voltage at the intermediate point is called the intermediate voltage of the ring network. As shown, U _a , U _b is the intermediate voltage of the Japanese word ring network.

Step 3 List the matrix equations for each edge (chain)

A- _day chain matrix equation

B- _day chain matrix equation

C- _day chain matrix equation

D- _day chain matrix equation

E- _day chain matrix equation

Step 4 Find the equal voltage points, as shown in the figure

Step 5 Find the current branch point and list the current equation

Step 6 Finish the matrix equation of the ring side

A- _day chain matrix equation

B- _day chain matrix equation

C- _day chain matrix equation

D- _day chain matrix equation

E- _day chain matrix equation

Step 7 List the complete equations of the ring and organize

Whole equation

After finishing

Step 8 List the whole equations in full form

Step 9 Solve the equations using the matrix method

Solution (the process is abbreviated, the solution method is a well-known method), and the matrix (2) is obtained as follows

(2) Design:

Substitute (2) as follows

Solve the following results

make

Substituting (4)

Solving (6)

Got

Step 10 According to the above results, the relationship between the intermediate voltage of the Japanese word ring network and the starting point voltage U _{1 of the} Japanese word ring network and the terminal voltage U ₂ of the Japanese word ring network can be obtained:

Step 11 According to the above results, the relationship between the starting branch current of the Japanese word loop, the starting branch current and the starting point voltage U _{1 of the} Japanese word ring network and the terminal voltage U ₂ of the Japanese word ring network can be obtained as follows:

Step 12 Calculate the relationship between the starting current and the terminal current of the Japanese word ring network and the starting point voltage U _{1 of the} Japanese word ring network and the terminal voltage U ₂ of the Japanese word ring network, as follows:

Let I ₁ and I ₂ be the starting current and the terminal current of the Japanese word ring network respectively.

Available

Step 13

Y parameter matrix of Japanese word ring network

According to the foregoing conversion method between the Y parameter matrix and the T parameter matrix, [Q _day ] = g ([Y _day ]), thereby calculating the power system composed of the R chain, the Japanese word ring network, and the S chain. The total matrix of the network [W]=[R]·[Q _日 ]·[S]=[R]·g([Y _日 ])·[S].

After completing the calculation of the total matrix of the Japanese word ring network, the total matrix is substituted into the following formula:

According to the above formula, the starting voltage of the power system network composed of the R chain, the Japanese word ring network, and the S chain can be calculated.

I _from 0;

Then, according to the electric power system network Qiduan voltage _from U and current I _from the borders of the R chains can be calculated successively, the word ring network, chain Qiduan voltage S, Qiduan current, the terminal voltage, current end.

by

Where: [R] ^-1 is the inverse matrix of the R chain;

The terminal voltage U _2,R of the R chain, the terminal current I _2,R and the starting voltage U _{1,Q of the Japanese} word ring network _, and the starting current I _1,Q _day can be calculated;

by

Where: [Q _day ] ^-1 is the inverse matrix of the Japanese word ring network;

The terminal voltage U ₂ of the Japanese word ring network _{, the Q day} , the terminal current I _{2 , the Q day} and the starting voltage U _{1,S of the} S chain _, and the starting current I _1,S can be calculated;

For the R chain and the S chain, the two can be regarded as a one-word chain power system, respectively. In one of the two chains, the calculation can be completed according to the "word-chain and branched-type three-phase symmetric multi-supply non-ring network power system straight algorithm" (the algorithm is the disclosed technology, patent number: 201410142938.7).

When the component to be calculated is located in the Japanese word ring network, the relevant calculation is performed according to its specific position. The calculation process is as follows: First, after the foregoing calculation, the starting voltage of the Japanese word ring network U ₁ = U _{1, Q day} and Terminal voltage U ₂ = U _{2, Q day} is known;

(1) Calculate the intermediate voltage U _a U _{b of the} Japanese word ring network:

(2) Calculate the starting current of each chain of the Japanese word ring network:

by

Can calculate the starting current of the A- _day chain I _{1, A day}

by

Can calculate the starting current of the B- _day chain I _{1, B day}

by

Calculate the starting current of the C- _day chain I _{1, C day}

by

Can calculate the starting current of the D- _day chain I _{1, D day}

by

The starting current I _{1, E day} of the E- _day chain can be calculated;

Then, according to the position of the component to be calculated at the position where the chain is located, the terminal voltage U _2,d-1 and the terminal current I _{2,d-1 of the} previous component of the component to be calculated are calculated as the starting voltage U of the component to be calculated. _{1, d} and the starting current I _1,d , then, according to the formula:

Third, the field word ring network

As shown in Figure 12, for the Tianzi ring network, it consists of eight sides (chains): A _field chain, B _field chain, C _field chain, D _field chain, E _field chain, F _field chain, G _field chain, H _{The field} chain, each side (chain) includes components: at least one transformer or one line in the main chain of the side (chain).

The first chain of the Tianzi ring network is the R chain, and the latter chain is the S chain. The R chain and the S chain are connected by a plurality of elements in sequence. The elements in the R chain and the S chain may be formed in the same order or in the same order. Similarly, multiplying the transmission parameter matrices of these components yields the total matrix [R] of the R chain and the total matrix [S] of the S chain. The calculation method for the merge matrix (transmission parameter matrix) of the field word ring network is as follows:

Step 1 Determine the starting point and end point of the ring network and its voltage point. U ₁ is the starting point voltage of the field word ring network, and U ₂ is the terminal voltage of the field word ring network.

Step 2 Determine the intermediate voltage of the ring network. As shown in the figure, U _a , U _b , and U _c are the intermediate voltages of the ring network.

Step 3 List the matrix equations for each edge

A _field chain equation

B _field chain equation

C _field chain equation

D _field chain equation

E _field chain equation

F _field chain equation

G _field chain equation

H _field chain equation

Step 4 Find the equal voltage points, as shown in the figure

Step 5 Find the current branch point and list the current equation

Step 6 Finish the matrix equation of the ring side

A _field chain matrix equation

B- _field chain matrix equation

C- _field chain matrix equation

D _field chain matrix equation

E _field chain matrix equation

F _field chain matrix equation

G _field chain matrix equation

H _field chain matrix equation

Step 7 List the complete equations of the ring and organize

Whole equation

After finishing

Step 8 List the whole equations in full form

Step 9 Solve the equations using the matrix method

Solution (the solution is the same as the solution of the Japanese word ring network, here is omitted), the matrix (2) is as follows

Step 10 According to the above results, the relationship between the intermediate node voltage of the field word ring network and the starting point voltage U _{1 of the} field word ring network and the terminal voltage U ₂ of the field word ring network can be obtained;

Step 11 According to the above results, the relationship between the starting branch current of the field word loop, the end branch current and the starting point voltage U _{1 of the} Tianzi ring network and the terminal voltage U ₂ of the Tianzi ring network can be obtained;

Step 12 Calculate the relationship between the starting current and the terminal current of the Tianzi ring network and the starting point voltage U _{1 of the} Tianzi ring network and the terminal voltage U ₂ of the Tianzi ring network;

Let I ₁ and I ₂ be the starting current and the terminal current of the ring net respectively.

Available

Step 13

Y-parameter matrix of Detian word ring network

Then, [Q _Tian ]=g([Y _Tian ]) is the total matrix (merge matrix) of the Tianzi ring network; after completing the calculation of the total matrix (merge matrix) of the Tianzi ring network, the R chain and the field ring network will be The total matrix of the merged matrix and the S chain is multiplied in the order of connection to obtain the total matrix of the total network:

[W]=[R]·[Q _田 ]·[S]=[R]·g([Y _田 ])·[S]

Substituting the total matrix [W] into the following formula:

Wherein, U is the electric power system _from the network (R chain and ring swastika chain S) Qiduan voltage, U is _{the end of} the terminal voltage of the electric power system network, the I current _from the borders of a power system network, and its value is equal to 0 The _end of I is the end current of the power system network, and its value is equal to zero.

According to the above formula, the starting voltage of the power system network composed of the R chain, the field ring network and the S chain can be calculated.

I _from 0;

Then, according to the electric power system network Qiduan voltage _from U and current I _from the borders of the R chains can be calculated successively, swastika ring, chain Qiduan voltage S, Qiduan current, the terminal voltage, current end.

by

Where: [R] ^-1 is the inverse matrix of the R chain;

The terminal voltage U _2,R of the R chain, the terminal current I _2,R and the starting voltage U _{1,Q field of the field} ring network, and the starting current I _1,Q _field can be calculated;

by

Where: [Q _field ] ^-1 is the inverse matrix of the field word ring network;

The terminal voltage U ₂ of the field word ring network _{, Q field} , terminal current I _2, the starting voltage U _{1,S of the} _{Q field} and the S chain _, and the starting current I _1,S can be calculated;

When the component to be calculated is located in the R chain or the S chain, the calculation manner is the same as the foregoing, and details are not described herein again.

When the component to be calculated is located in the field word loop network, relevant calculations are performed according to its specific location, and the calculation process is as follows:

First, after the above calculation, the starting voltage U ₁ = U _{1, the Q field} and the terminal voltage U ₂ = U _{2 of the} Tianzi ring network are known.

(1) Calculate the voltage of the intermediate node of the Tianzi ring network

(2) Calculate the starting current of each side (chain) in the field ring network

by

Can calculate the starting current of the A _field chain I _{1, A field}

by

Can calculate the starting current of the B _field chain I _{1, B field}

by

Can calculate the starting current of the C _field chain I _{1, C field}

by

Can calculate the starting current of the D _field chain I _{1, D field}

by

Can calculate the starting current of the E _field chain I _{1, E Tian}

by

Can calculate the starting current of the F _field chain I _{1, F field}

by

Can calculate the starting current of the G _field chain I _{1, G Tian}

by

Calculated _field H chain Qiduan current I _{1, H TIAN}

Fourth, the word ring network

As shown in FIG. 13, for the target ring network, it is composed of eight sides (chains): A _mesh chain, B _mesh chain, C _mesh chain, D _mesh chain, E _mesh chain, F _mesh chain, G _mesh chain, H. _{In the} chain of _eyes , each side (chain) includes components: at least one transformer or one line in the main chain of the side (chain).

The first chain of the ring of the mesh is the R chain, and the latter chain is the S chain. The R chain and the S chain are connected by a plurality of elements in sequence. The components in the R chain and the S chain may be formed in the same order or in the same order. Similarly, multiplying the transmission parameter matrices of these components yields the total matrix [R] of the R chain and the total matrix [S] of the S chain. The calculation method of the merge matrix (transmission parameter matrix) of the target ring network is as follows:

Step 1 Determine the starting point and end point of the ring network and its voltage point. U ₁ is the starting point voltage of the ring network and U ₂ is the end point voltage of the ring network.

Step 2 Determine the intermediate voltage of the ring network, as shown in Figure U _a , U _b , U _c , U _d is the intermediate voltage of the target ring network

Step 3 List the matrix equations for each edge (chain)

A _- chain equation

Equation _program chain B

C _- chain equation

D _- chain equation

E _- chain equation

F _program chain equation

_Program chain equation G

_Program chain equation H

Step 4 Find the equal voltage points, as shown in the figure

Step 5 Find the current branch point and list the current equation

Step 6 Finish the matrix equation of the ring side

A _mesh chain matrix equation

B _- chain matrix equation

C _- chain matrix equation

D _mesh chain matrix equation

E _mesh chain matrix equation

F _- chain matrix equation

G _mesh chain matrix equation

H _mesh chain matrix equation

Step 7 List the complete equations of the ring and organize

Whole equation

After finishing

Step 8 List the equations in full form

Step 9 Solve the equations using the matrix method

Solution (the process is the same as the Japanese word ring network solution, here is omitted), the matrix (2) is as follows

Step 10 According to the above result, the relationship between the intermediate point voltage of the target ring network and the starting point voltage U _{1 of the} mesh ring network and the end point voltage U ₂ of the mesh ring network can be obtained.

Step 11 According to the above results, the relationship between the starting point branch current and the end branch current of the mesh ring network and the starting point voltage U _{1 of the} mesh ring network and the end point voltage U ₂ of the mesh ring network can be obtained.

Step 12 Calculate the relationship between the starting point current and the end current of the target ring network and the starting point voltage U _{1 of the} mesh ring network and the end point voltage U ₂ of the mesh ring network.

Let I ₁ and I ₂ be the starting current and the ending current of the ring network respectively.

Available

Step 13 calculates the parameter Y words ring mesh matrix [Y _mesh]

make

Y parameter matrix of the mesh ring network

Then [Q _目 ]=g([Y _目 ]) is the total matrix of the target ring network

After the calculation of the total matrix (merge matrix) of the target ring network is completed, the total matrix of the total network is obtained by multiplying the merged matrix of the R chain and the mesh ring network and the total matrix of the S chain in order of connection:

[W]=[R]·[Q _目 ]·[S]=[R]·g([Y _目 ])·[S]

Substituting the total matrix [W] into the following formula:

Wherein, U is the electric power system _from the network (R chain, ring and mesh word chain S) Qiduan voltage, U is _{the end of} the terminal voltage of the electric power system network, the I current _from the borders of a power system network, and its value is equal to 0 The _end of I is the end current of the power system network, and its value is equal to zero.

According to the above formula, the starting voltage of the power system network composed of the R chain, the mesh ring and the S chain can be calculated.

I _from 0;

Then, the R chains can be calculated successively, the word mesh ring, chain S Qiduan voltage, current, terminal voltage, according to the current _from the base end of the power system network voltage U and the borders _from current I.

by

Where: [R] ^-1 is the inverse matrix of the R chain, and the terminal voltage U _2,R , the terminal current I _2,R of the R chain _, and the starting voltage U _1,Q and the starting point of the mesh ring network can be calculated. Current I _{1, Q mesh} ;

by

Where: [Q _target ] ^-1 is the inverse matrix of the mesh of the target word;

The terminal voltage U _{2 , the Q mesh} , the terminal current I _{2 , the Q mesh} and the starting voltage U 1S of the S chain _, and the starting current I _{1 S} can be calculated.

When the component to be calculated is located in the mesh of the mesh, the relevant calculation is performed according to its specific location, and the calculation process is as follows:

First, after the foregoing calculation, the starting voltage U ₁ = U _{1, the Q mesh} and the terminal voltage U ₂ = U _{2 of the} mesh ring are known.

(1) Calculate the intermediate voltage of the target ring network:

(2) Calculate the starting current of each side (chain) of the target ring network

by

Can calculate the starting current of the A _mesh chain I _{1, A mesh}

by

Can calculate the starting current of the B _mesh chain I _{1, B mesh}

by

Can calculate the starting current of the C _mesh chain I _{1, C mesh}

by

Can calculate the starting current of the D _mesh chain I _{1, D mesh}

by

The starting current I ₁ of the E _mesh chain can be calculated _.

by

Can calculate the starting current of the F _mesh chain I _{1, F mesh}

by

Can calculate the starting current of the G _mesh chain I _{1, G mesh}

by

Can calculate the starting current of the H _mesh chain I _{1, H mesh}

The present invention can be preferably implemented in accordance with the above embodiments. It should be noted that, based on the above design principles, in order to solve the same technical problem, even if some substantial changes or retouchings are made on the basis of the disclosed structure, the essence of the technical solution adopted is still As with the present invention, it should also be within the scope of the present invention.

Claims

A power flow direct calculation method for a power system, characterized in that the method comprises the following steps:

(1) Calculate the total matrix of the entire power system network:

(2) Substituting the total matrix of the power system network into the following formula:

(3) Calculate the starting voltage of the power system network

(4) According to the following formula, the terminal voltage U 2,d and the terminal current I 2,d of each component are sequentially calculated according to the connection order of the components:

Wherein, according to the connection order of the components, the terminal voltage and the terminal current of the previous component are the starting voltage and the starting current of the latter component;

(5) Calculate the operating voltage, operating current and power loss of the component according to the calculated starting voltage, starting current, terminal voltage and terminal current of the component;

Wherein, U is from the borders of a power system network voltage, U is the end of the terminal voltage of the electric power system network, the I current from the borders of a power system network, which is equal to 0, I is the tail current at the end of a power system network, which The value is equal to 0, [W total ] represents the total matrix of the power system network, [A d ] represents the matrix of a component, U 1,d represents the starting voltage of the component, and I 1,d represents the starting current of the component, U 2 , d represents the terminal voltage of the component, and I 2,d represents the terminal current of the component;

The specific manner of the step (1) is as follows:

(11) Calculating the matrix of each node;

(12) sequentially multiplying the matrix of each node according to the connection order of each node to obtain a total matrix of the power system network;

The node includes: a basic node composed of a single component, a chain node corresponding to a chain composed of a plurality of basic nodes, a basic ring network node corresponding to a basic ring network composed of a plurality of chain nodes, and a plurality of basic ring network nodes, a combined ring network node corresponding to the combined ring network formed by the chain node socket;

Wherein, the matrix of the basic node is a matrix of components, the matrix of the chain nodes is equal to the matrix of each component in the chain, and the matrix of the basic ring network is obtained by combining the matrix of the constructed chain nodes, the ring network The matrix of the nodes is obtained by combining the formed chain nodes and the matrix of the basic ring network nodes;

The component includes any one or more of a generator, a load, a transformer, and a line. Correspondingly, the matrix of the generator is
The matrix of the load is
The concentrated parameter matrix of the line is
And distributed parameter model matrix
The matrix of the transformer is
Where E is the ideal voltage of the generator, r is the internal impedance of the generator, Y is the admittance of the load, Z is the impedance of the line, n 1 and n 2 are the number of turns of the primary side of the transformer, respectively. Parametric model matrix
When:
The power flow direct calculation method for a power system according to claim 1, wherein the basic ring network is a combined matrix calculation method of a spoken word ring network as follows:

First, calculate the transmission parameter matrix of the A- port chain and the B- port chain in the word-ring ring network:
with
Wherein, the transmission parameter matrix of each chain is equal to the matrix of all components in the chain, which are sequentially obtained according to the connection order of the components;

Secondly, convert [A port ] and [B port ] into corresponding admittance parameter matrices: [A port '] and [B port '];

Second, add [A port '] and [B port '] according to the following formula:

Finally, the calculation result of [ A'port ]+[ B'port ] is converted into a transmission parameter matrix, which is the merge matrix of the word ring network.
The power flow direct calculation method for a power system according to claim 1, wherein the basic ring network is a merge matrix calculation method of a Japanese word ring network as follows:

First, calculate the transmission parameter matrix of the A- day chain, the B- day chain, the C- day chain, the D- day chain, and the E- day chain in the Japanese word ring network:

Wherein, the transmission parameter matrix of each chain is equal to the matrix of all components in the chain, which are sequentially obtained according to the connection order of the components;

After solving, the admittance parameter matrix of the Japanese word ring network can be obtained:
And the intermediate point voltage as a function of the starting voltage and terminal voltage of the Japanese word ring network

Finally, the calculated admittance parameter matrix:
Converted to a transmission parameter matrix, which is the merge matrix of the Japanese word ring network.
The power flow direct calculation method for a power system according to claim 1, wherein the basic ring network is a merge matrix calculation method of the field word ring network as follows:

First, calculate the transmission parameter matrix of the A field chain, the B field chain, the C field chain, the D field chain, the E field chain, the F field chain, the G field chain, and the H field chain in the Tianzi ring network:

Wherein, the transmission parameter matrix of each chain is equal to the matrix of all components in the chain, which are sequentially obtained according to the connection order of the components;

Then, calculate the admittance parameter matrix of the field word ring network
And the intermediate point voltage as a function of the starting voltage and terminal voltage of the field ring network

Finally, the calculated admittance parameter matrix:
Converted to a transmission parameter matrix, which is the merge matrix of the field word ring network.
The power flow direct calculation method for a power system according to claim 1, wherein the basic ring network is a merge matrix calculation method of the mesh ring network as follows:

Firstly, calculate the transmission parameter matrix of the A mesh chain, the B mesh chain, the C mesh chain, the D mesh chain, the E mesh chain, the F mesh chain, the G mesh chain, and the H mesh chain in the target ring network:

Wherein, the transmission parameter matrix of each chain is equal to the matrix of all components in the chain, which are sequentially obtained according to the connection order of the components;

Then, calculate the admittance parameter matrix of the mesh of the mesh
And the intermediate point voltage as a function of the starting voltage and terminal voltage of the ring

Finally, the calculated admittance parameter matrix:
Converted to a transmission parameter matrix, which is the merge matrix of the target ring network.
The power flow direct calculation method for a power system according to claim 1, wherein the calculation method of the components in the basic ring network is as follows:

(a) calculating the terminal voltage and terminal current of the basic ring network based on the starting voltage of the basic ring network and the starting current and the combined matrix of the basic ring network;

(b) Calculate the basic voltage of the basic ring network according to the relationship between the starting voltage and the terminal voltage of the basic ring network and the intermediate voltage of the basic ring network and the starting voltage and the terminal voltage of the ring network; thus knowing the starting point of each side of the basic ring network Voltage and terminal voltage;

(c) calculating the starting current of each side according to the starting voltage and the terminal voltage of each side of the basic ring network and the matrix of each side;

(d) According to the following formula, the terminal voltage U 2,d and the terminal current I 2,d of each component are sequentially calculated according to the connection order of the components in the chain;

Wherein, according to the connection order of the components in the chain, the terminal voltage and the terminal current of the previous component are the starting voltage and the starting current of the latter component; U 1,d represents the starting voltage, and I 1,d represents the starting current. [A d ] represents the transmission matrix of a node in a chain in the ring network.