WO2018209482A1

WO2018209482A1 - Balanced conductance compensation-type global linear eccentricity method for obtaining power flow of direct-current power grid

Info

Publication number: WO2018209482A1
Application number: PCT/CN2017/084290
Authority: WO
Inventors: 彭建春; 江辉
Original assignee: 深圳大学
Priority date: 2017-05-15
Filing date: 2017-05-15
Publication date: 2018-11-22
Also published as: CN109257945B; CN109257945A

Abstract

A balanced conductance compensation-type global linear eccentricity method for obtaining a power flow of a direct-current power grid comprises: first, according to a node load parameter and a node power supply parameter in a direct-current power grid, establishing a balanced conductance compensation-type global linear relation about a node injection power and a node translation voltage (101); then, establishing a balanced conductance compensation-type global linear eccentric model of a power flow in the direct-current power grid according to the balanced conductance compensation-type global linear relation and a reference node number (102); then, establishing a balanced conductance compensation-type global linear eccentric matrix relation about a non-reference node translation voltage and a non-reference node injection power according to the balanced conductance compensation-type global linear eccentric model (103); and finally, computing a voltage value of each node and a transmission power value of each branch in the direct-current power grid according to the balanced conductance compensation-type global linear eccentric matrix relation and a reference node translation voltage value (104). The computing amount is small, the convergence problem does not exist, and the precision is high when the operating state of the direct-current power grid changes in a great range.

Description

Equilibrium Conductance Compensation Global Linear Eccentric Method for Obtaining Power Flow of DC Power Network

Technical field

The invention relates to the field of electric power engineering, in particular to an equalization conductance compensation type global linear eccentricity method for acquiring a power flow of a direct current power network.

Background technique

At present, the technical and economic advantages of HVDC transmission are rapidly driving the construction and development of DC power grids. As a basis for the regulation of DC power network, the trend, especially the fast, reliable and accurate global linear power flow model and calculation method need to be developed.

The existing DC power network power flow acquisition method is to first establish a nonlinear node power balance equation model, and then use an iterative method to solve. Due to the nonlinearity of the node power balance equation model, this method not only has a large amount of iterative computation and slow speed, but also has an iterative non-convergence or unreliable convergence problem. It is difficult to adapt to the DC power network operation that needs to be controlled based on the power flow solution. Claim. If the local linear power flow model based on the running base point linearization is adopted, the accuracy requirement of the regulation of the DC power network operating state can not be satisfied. Therefore, the existing DC power network power flow acquisition method either has a problem of slow calculation speed and unreliable convergence, or does not adapt to a wide range of changes in the operating state of the DC power network.

Summary of the invention

Embodiments of the present invention provide an equalization conductance compensation type for acquiring a power flow of a DC power network The global linear eccentricity method can realize the fast and reliable acquisition of the DC power network power flow, and adapt to the wide range of operation of the DC power network.

The invention provides an equalization conductance compensation global linear eccentricity method for acquiring a power flow of a DC power network, comprising:

Establishing an equalized conductance compensation global linear relationship of the node injection power with respect to the node translation voltage according to the known node load parameter and the node power parameter in the DC power network;

Establishing a balanced conductance compensation global linear eccentricity model for the tidal current in the DC power network according to the balanced conductance compensation type global linear relationship and the known reference node number;

According to the equalization conductance compensation type global linear eccentricity model, an inverse matrix is used to establish a balanced conductance compensation global linear eccentric matrix relation of a non-reference node translation voltage with respect to a non-reference node injection power;

Calculating a voltage value of each node in the DC power network and a transmission power value of each branch according to the balanced conductance compensation type global linear eccentric matrix relationship and a known reference node translation voltage value.

The embodiment of the present invention first establishes a global linear relationship of the equalization conductance compensation type of the node injection power with respect to the node translation voltage according to the node load parameter and the node power parameter in the known DC power network; and then according to the global linear relationship of the balanced conductance compensation type And the known reference node number is used to establish the balanced conductance compensation global linear eccentricity model of the tidal current in the DC power network; and according to the balanced conductance compensation global linear eccentricity model, the inverse matrix is used to establish the non-reference node translation voltage with respect to the non-reference node injection power. Balanced conductance compensation type global linear eccentric matrix relation; finally, according to the equilibrium conductance compensation type global linear eccentric matrix relation and the known reference node translation voltage value, calculate the sections in the DC power network The voltage value of the point and the transmission power value of each branch; since iterative calculation is not required, the calculation amount is small, there is no convergence problem, and the accuracy is high when the operating state of the DC power network is widely changed.

DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are some embodiments of the present invention. For the ordinary technicians, other drawings can be obtained based on these drawings without any creative work.

FIG. 1 is a flowchart of an implementation of an equalization conductance compensation global linear eccentricity method for acquiring a power flow of a DC power network according to an embodiment of the present invention; FIG.

2 is a schematic structural diagram of a general model of a DC power network according to an embodiment of the present invention.

detailed description

In the following description, for purposes of illustration and description However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the invention.

In order to explain the technical solution described in the present invention, the following description will be made by way of specific embodiments.

Referring to FIG. 1, FIG. 1 is a schematic diagram of obtaining a DC power network trend according to an embodiment of the present invention. Flow chart of the implementation of the balanced conductance compensation global linear eccentricity method. The balanced conductance compensation global linear eccentricity method for obtaining the DC power network power flow as shown in the figure may include the following steps:

In step 101, an equalized conductance compensation global linear relationship of the node injection power with respect to the node translation voltage is established according to the node load parameter and the node power parameter in the known DC power network.

Step 101 is specifically: establishing a global linear relationship of the balanced conductance compensation type of the node injection power with respect to the node translation voltage according to the following relationship:

Where i and k are the numbers of the nodes in the DC power network, and both belong to the set of consecutive natural numbers {1, 2,..., n}; n is the total number of nodes in the DC power network; P _Gi is connected The power of the power at node i; P _Di is the load power connected to node i; P _Gi -P _Di is the injected power of node i; g _ik is the conductance of branch ik connected between node i and node k; _i is the translation voltage of node i; v _k is the translation voltage of node k, and both v _i and v _k are the standard value voltage after translation -1.0; v _i0 is the base translation voltage of node i; v _k0 is node k The base point shifts the voltage, and both v _i0 and v _k0 are the target voltages after the translation of -1.0.

P _Gi , P _Di , n, g _ik , v _i0 , v _k0 are all known DC power network parameters.

All the variables in the above-mentioned balanced conductance compensation type global linear relation are global variables, not increments; in addition, the coefficients of v _i and v _k in the above-mentioned equalization conductance compensation type global linear relation (1+v _i0 -0.5v _K0 )g _ik and -(1+0.5v _i0 )g _ik are self-conducting and mutual conductance, respectively, which increase the conductance term (v _i0 -0.5v _k0 )g _ik and the conventional self-conductance and mutual conductance, respectively. -0.5v _i0 g _ik . These two conductance terms are the equalization of the nonlinear term of the original power expression on the right side of the above relation (that is, assigned according to the Shapley value) to v _i and v _k , and then the coefficients of v _i and v _k are collected and quantized at the base point. These two coefficients are obtained to compensate for the nonlinear term of the original power expression. This is why the above relationship is called the balanced conductance compensation global linear relation of the node injection power with respect to the node translation voltage.

The above-mentioned balanced conductance compensation global linear relationship is established according to the operating characteristics of the DC power network. The operating characteristic of the DC power network is that the "node translation voltage" obtained after the voltage of each node in the DC power network is shifted to -1.0 is small, and the constant is used instead of the branch. The product of the path conductance and its end node translation voltage has little effect on the accuracy of the result.

In step 102, a balanced conductance compensation global linear eccentricity model of the tidal current in the DC power network is established according to the balanced conductance compensation type global linear relationship and the known reference node number.

Step 102 is specifically: establishing a balanced linear conductivity eccentricity model of the tidal current in the DC power network according to the following relationship:

Where P _G1 is the power supply of node 1; P _Gi is the power supply of node i; P _Gn-1 is the power supply of node n-1; P _D1 is the load power of node 1; P _Di is the load power of node i ; P _Dn-1 is the load power of node n-1; j is the number of nodes in the DC power network, and belongs to the set of consecutive natural numbers {1, 2, ..., n}; g _ii is connected at node i and node j ij is the conductance between the branches; G _ik ik is connected to the branch conductance between nodes i and k; v _I0 is a point offset in the voltage of node i; _kO v is a translation point voltage node k, and v Both _i0 and v _k0 are the standard value voltage after translation -1.0; n is the total number of nodes in the DC power network; the node numbered n is a known reference node; (G _ij ) is the reference node deleted The equalization conductance compensation type node conductance matrix of the DC power network after row and column, the dimension of the equalization conductance compensation type node conductance matrix is (n-1) × (n-1); G _ij is the equalization conductance compensation type node conductance matrix The element of the i-th row and the j-th column in (G _ij ); v ₁ is the translation voltage of node 1; v _i is the translation voltage of node i; v _n-1 is the translation voltage of node n-1 And v ₁ , v _i and v _n-1 are the target voltages after translation -1.0.

P _G1 , P _D1 , P _Gi , P _Di , P _Gn-1 , P _Dn-1 , (G _ij ) are known DC power network parameters.

In the above-mentioned balanced conductance compensation type global linear eccentricity model, the translation voltage of the reference node is assigned to a voltage center of zero value, and the center is completely biased toward the reference node, which is why the above model is a balanced conductance compensation type global linear eccentricity model.

In step 103, according to the equalization conductance compensation type global linear eccentricity model, an inverse matrix is used to establish an equalization conductance compensation type global linear eccentric matrix relation of the non-reference node translation voltage with respect to the non-reference node injection power.

Step 103 is specifically: establishing a balanced conductance compensation global linear eccentric matrix relationship of the non-reference node translation voltage with respect to the non-reference node injection power according to the following relationship:

Where (G _ij ) ^-1 is the inverse matrix of the equalization conductance compensation node conductance matrix (G _ij ) of the DC power network; P _G1 is the power supply of node 1; P _Gi is the power supply of node i; P _Gn-1 Is the power supply of node n-1; P _D1 is the load power of node 1; P _Di is the load power of node i; P _Dn-1 is the load power of node n-1; v ₁ is the translation voltage of node 1; _i is the translation voltage of node i; v _n-1 is the translation voltage of node n-1, and v ₁ , v _i and v _n-1 are the standard value voltages after translation -1.0. According to the above relationship, the non-reference node translation voltage values v _i , i=1, 2, . . . , n-1 can be calculated.

Since the above-mentioned balanced conductance compensation type global linear eccentric matrix relation is a global variable (rather than an incremental) relation, the non-reference node translation voltage calculated according to it is changed when the node injection power is widely changed, that is, the DC power network operation state. The wide range of changes is accurate, and the calculation process involves only one simple linear relationship calculation, fast and reliable.

In step 104, the voltage values of the nodes in the DC power network and the transmission power values of the branches are calculated according to the balanced conductance compensation type global linear eccentric matrix relationship and the known reference node translation voltage values.

Step 104 is specifically: calculating a non-reference node translation voltage value according to the equilibrium conductance compensation type global linear eccentric matrix relation; and calculating a non-reference node voltage in the DC power network according to the following three reference relations according to the known reference node translation voltage value Value, reference node voltage value and transmission power value of each branch:

V _i =1+v _i +v _n

V _n =1+v _n

P _ij =g _ij (v _i -v _j )

Wherein, V _{i is a} non-reference node voltage value, i=1, 2, . . . , n−1; V _n is a reference node voltage value; v _n is a reference node translation voltage value, and is a target value after translation-1.0 Voltage; v _i is the translation voltage of node i; v _j is the translation voltage of node j, and v _i and v _j are the standard value voltages after translation -1.0; g _ij is connected between node i and node j The conductance of the branch ij; P _ij is the branch ij transmission power value, also known as the branch current.

In this way, the distribution of the balanced conductance-compensated global linear power flow in the DC power network is obtained. The above calculation formula is based on the non-reference node translation voltage and is very simple. The calculation of the non-reference node translation voltage is accurate, fast and reliable when the operating state of the DC power network varies widely. Therefore, the balanced linear conductance compensation global linear eccentricity model and algorithm for tidal currents in DC power grids are accurate, fast, and reliable.

It should be understood that the size of the sequence of the steps in the above embodiments does not mean that the order of execution is performed, and the order of execution of each process should be determined according to its function and internal logic, and should not be construed as limiting the implementation process of the embodiments of the present invention.

Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods for implementing the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.

Claims

An equalization conductance compensation type global linear eccentricity method for obtaining a power flow of a DC power network, characterized in that the method for obtaining a balanced conductance compensation type global linear eccentricity of a power flow of a DC power network comprises:

Establishing an equalized conductance compensation global linear relationship of the node injection power with respect to the node translation voltage according to the known node load parameter and the node power parameter in the DC power network;

Establishing a balanced conductance compensation global linear eccentricity model for the tidal current in the DC power network according to the balanced conductance compensation type global linear relationship and the known reference node number;

According to the equalization conductance compensation type global linear eccentricity model, an inverse matrix is used to establish a balanced conductance compensation global linear eccentric matrix relation of a non-reference node translation voltage with respect to a non-reference node injection power;

Calculating a voltage value of each node in the DC power network and a transmission power value of each branch according to the balanced conductance compensation type global linear eccentric matrix relationship and a known reference node translation voltage value.
The equalization conductance compensation type global linear eccentricity method for acquiring a DC power network power flow according to claim 1, wherein the node injection power is established according to a node load parameter and a node power parameter in a known DC power network. The global linear relationship of the balanced conductance compensation type of the translation voltage is as follows:

The equilibrium current-conductance compensation global linear relationship of the node injection power with respect to the node translation voltage is established according to the following relationship:

Where i and k are the numbers of the nodes in the DC power network, and both belong to the set of consecutive natural numbers {1, 2, ..., n}; n is the total number of nodes in the DC power network; P Gi Is the power supply to the node i; P Di is the load power connected to the node i; P Gi -P Di is the injection power of the node i; g ik is connected between the node i and the node k The conductance of the branch ik; v i is the translation voltage of the node i; v k is the translation voltage of the node k, and the v i and the v k are both the standard value voltage after the translation -1.0 ; v i0 is the base point translation voltage of the node i; v k0 is the base point translation voltage of the node k, and the v i0 and the v k0 are both the standard value voltage after the translation -1.0.
The equalization conductance compensation type global linear eccentricity method for acquiring a power flow of a DC power network according to claim 1, wherein said establishing a DC power network according to said balanced conductance compensation type global linear relationship and a known reference node number The equal-conductance-compensated global linear eccentricity model of the medium-flow is specifically:

An equilibrium conductance compensation global linear eccentricity model for tidal currents in a DC power network is established according to the following relationship:

Where P G1 is the power supply power of node 1; P Gi is the power supply power of node i; P Gn-1 is the power supply power of node n-1; P D1 is the load power of the node 1; P Di is the node The load power of i; P Dn-1 is the load power of the node n-1; j is the number of nodes in the DC power network, and belongs to the set of continuous natural numbers {1, 2, ..., n}; g ij Is the conductance of the branch ij connected between the node i and the node j; g ik is the conductance of the branch ik connected between the node i and the node k; v i0 is the node i translating point voltage; v k0 is the starting point of the translation of a voltage node k, and the v i0 v k0 and the translation are pu voltage of -1.0; n is the current power total nodes in the network Number; the node numbered n is a known reference node; (G ij ) is the equalization conductance compensation type node conductance matrix of the DC power network after deleting the row and column of the reference node, the equalization conductance compensation type node conductance matrix the dimension is (n-1) × (n -1); G ij is the element of the equalization compensated conductance node conductance matrix (G ij) in row i and column j; v 1 is the Translating the voltage at node 1; V i is the offset in the voltage of the node i; V n-1 is the voltage of the node translating n-1, and the v 1, V i and the n-1 are the V It is the standard value voltage after translation -1.0.
The equalization conductance compensation type global linear eccentricity method for acquiring a power flow of a DC power network according to claim 1, wherein the non-reference node translation voltage is established by using an inverse matrix according to the equalization conductance compensation type global linear eccentricity model The equilibrium conductance compensation type global linear eccentric matrix relation of the non-reference node injection power is as follows:

The equilibrium conduction conductance-compensated global linear eccentric matrix relation of the non-reference node translation voltage with respect to the non-reference node injection power is established according to the following relationship:

Wherein, (G ij ) -1 is an inverse matrix of the equalization conductance compensation type node conductance matrix (G ij ) of the DC power network; P G1 is the power supply power of the node 1; P Gi is the power supply power of the node i; P Gn power -1 nodes of the n-1; P D1 to the load power node 1; P Di of the power to the load node i; P Dn-1 is the load power of the node n-1; 1 V Is the translation voltage of the node 1; v i is the translation voltage of the node i; v n-1 is the translation voltage of the node n-1, and the v 1 , the v i and the v n -1 is the standard value voltage after translation -1.0.
The equalization conductance compensation type global linear eccentricity method for acquiring a power flow of a DC power network according to claim 1, wherein said global linear eccentric matrix relationship according to said equalization conductance compensation type and a known reference node translation voltage value Calculating the voltage value of each node in the DC power network and the transmission power value of each branch are specifically:

Calculating a non-reference node translation voltage value according to the balanced conductance compensation type global linear eccentric matrix relation;

According to the known reference node translation voltage value, the non-reference node voltage value, the reference node voltage value, and each branch transmission power value in the DC power network are respectively calculated according to the following three relations:

V i =1+v i +v n

V n =1+v n

P ij =g ij (v i -v j )

Wherein, V i is the non-reference node voltage value, i=1, 2, . . . , n-1; V n is the reference node voltage value; v n is the reference node translation voltage value, and is translation- The threshold voltage after 1.0; v i is the translation voltage of node i; v j is the translation voltage of node j, and the v i and the v j are the standard value voltage after translation -1.0; g ij Is the conductance of the branch ij connected between the node i and the node j; P ij is the branch ij transmission power value.