CN103632015B - Equating method and device based on actual measurement information of boundary nodes for two-port network - Google Patents

Abstract

The invention discloses an equating method and device based on the actual measurement information of boundary nodes for a two-port network. The equating method comprises the following steps: obtaining direct parameters at first, and then calculating indirect parameters according to the direct parameters, and constructing a simulation model according to the direct parameters and the indirect parameters, wherein the simulation model is used for supplying power to an internal system network in the form of voltage source series impedance. On the basis, the internal system network can be rapidly simulated, so that the simulation progress can be accelerated, thus increasing the working efficiency.

Description

A kind of two-port Equivalent Network method and device based on boundary node real measured data

Technical field

The application is related to technical field of electric power, more particularly, it relates to a kind of two ends based on boundary node real measured data Mouth Equivalent Network method and device.

Background technology

At present when the accident to alternating current-direct current bulk power grid carries out transient analysis, mainly pass through the electricity such as pscad/emtdc, rtds Magnetic transient emulation instrument is emulated to accident and is analyzed.If comprehensive electromagnetic transient simulation is carried out to practical power systems, Often waste time and energy.And when transient analysis is carried out to power system, the typically also simply related change to certain part therein The temporal variations process of amount is interested, therefore, in order to improve the efficiency of transient emulation process, can be only to part net interested Network carries out detailed emulation, and this subnetwork is referred to as built-in system network；And for remainder network carry out simplifying equivalent and Accelerate its simulation process, this subnetwork is referred to as external system network.

Content of the invention

In view of this, the application provides a kind of two-port Equivalent Network method based on boundary node real measured data and dress Put, for carrying out to outside grid simplifying equivalent, structure simulation model, to accelerate the emulation of internal grid is entered Journey.

To achieve these goals it is proposed that scheme as follows:

A kind of two-port Equivalent Network method based on boundary node real measured data, comprising:

Obtain the direct parameter of the boundary node of external system network；

Described direct parameter is substituted into default equation group, is calculated indirect parameter；

Simulation model is built according to described direct parameter and described indirect parameter.

Preferably, described direct parameter include the node voltage phasor of described boundary node and interconnection active power and Reactive power.

Preferably, described equation group is node power flow equation group.

Preferably, described indirect parameter is the equivalent parameters of external system network, including voltage source phasor, equivalent self-impedance And coupled impedance.

A kind of two-port Equivalent Network device based on boundary node real measured data, comprising:

Measuring unit, for obtaining the direct parameter of the boundary node of external system network；

Computing unit, for described direct parameter is substituted into default equation group, is calculated indirect parameter；

Analogue unit, for building simulation model according to described direct parameter and described indirect parameter, and with voltage subject string Connection impedance manner internally power by grid.

Preferably, described direct parameter includes the node voltage of described border economize on electricity and the active power of interconnection and idle Power.

Preferably, described equation group is node power flow equation group.

Preferably, described indirect parameter is the equivalent parameters of external system model, including voltage source phasor, equivalent self-impedance And coupled impedance.

From technique scheme as can be seen that the equivalence method of power system of the application offer and device obtain directly first Connect parameter, then make a thorough investigation of direct parameter and calculate indirect parameter, and simulation model is built according to direct parameter and indirect parameter, this is imitated True mode is that voltage source series impedance form internally power by grid.Based on this can be quickly to internal grid Emulated such that it is able to be accelerated simulation process, improve operating efficiency.

Brief description

In order to be illustrated more clearly that the embodiment of the present application or technical scheme of the prior art, below will be to embodiment or existing Have technology description in required use accompanying drawing be briefly described it should be apparent that, drawings in the following description be only this Some embodiments of application, for those of ordinary skill in the art, on the premise of not paying creative work, acceptable Other accompanying drawings are obtained according to these accompanying drawings.

Fig. 1 is a kind of two-port Equivalent Network method based on boundary node real measured data disclosed in the embodiment of the present application Flow chart；

Fig. 2 is the network structure after power system Equivalent Simplification；

Fig. 3 is the structure chart of the simulation model of the embodiment of the present application；

Fig. 4 is a kind of two-port Equivalent Network dress based on boundary node real measured data disclosed in another embodiment of the application The structure chart put；

Fig. 5 is the topology diagram of the power system master pattern of ieee14 node；

Fig. 6 is that circuit 4-5 interlude occurs three-phase ground fault, and on bus 4 and bus 5 before and after equivalence, the transient state of voltage is special The comparison diagram of property；

Fig. 7 is that circuit 4-5 interlude occurs three-phase ground fault, the active power on circuit 2-5 and idle before and after equivalence The transient characterisitics comparison diagram of power；

Fig. 8 is that circuit 4-5 interlude occurs three-phase ground fault, the active power on circuit 3-4 and idle before and after equivalence The transient characterisitics comparison diagram of power；

Fig. 9 is that circuit 4-5 interlude occurs three-phase ground fault, the active power on circuit 2-4 and idle before and after equivalence The transient characterisitics comparison diagram of power.

Specific embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present application, the technical scheme in the embodiment of the present application is carried out clear, complete Site preparation describes it is clear that described embodiment is only some embodiments of the present application, rather than whole embodiments.It is based on Embodiment in the application, it is every other that those of ordinary skill in the art are obtained under the premise of not making creative work Embodiment, broadly falls into the scope of the application protection.

Embodiment one

According to the needs studying a question, by any one complicated practical power systems network be divided into built-in system network, Boundary system and external system network three part.If the border section being connected between external system network and built-in system network Point has two, then just constitute a typical two-port network after system simplifies equivalence, and its structure is as shown in Figure 2.

For unknown external system network or known external system but the complicated network structure, ensure boundary node tide Under conditions of stream, short-circuit voltage level are basically identical, external system can in the form of equivalence is for voltage source series impedance internally Grid is powered, if electrical distance in outside grid for the two adjacent sections point more closely has a certain degree of coupling and closes System, then also need the coupled impedance between meter and node when expressing external system network structure.

After clear and definite the above, simulation model is built according to following method, Fig. 1 is based on for one kind disclosed in the present embodiment The flow chart of the two-port Equivalent Network method of boundary node real measured data.

As shown in figure 1, two-port Equivalent Network method comprises the steps: disclosed in the embodiment of the present application

S101: obtain direct parameter.

Obtain power system border economize on electricity direct parameter, direct parameter include border economize on electricity node voltage phasor and The active power of interconnection and reactive power.

S102: calculate indirect parameter.

The direct parameter being obtained according to previous step, the such as node voltage phasor of boundary node and the active power of interconnection And reactive power, direct parameter is substituted into default equation group, is calculated indirect parameter.Default equation group is node trend Equation, indirect parameter is the equivalent parameters of i.e. external system model, including voltage source phasor, equivalent self-impedance and coupled impedance.

Theoretical according to network topology, the node trend writing boundary node i is arranged to equivalent external system network, boundary system Equation.

$\left\{\begin{array}{c}{p}_i=e_i{u}_i[g_i\cos ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)+b_i\sin ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)]-g_i{u_i}^2+{(-1)}^i\mathrm{\δp}\\ q_i=e_i{u}_i[g_i\sin ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)-b_i\cos ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)]+b_i{u_i}^2+{(-1)}^i\mathrm{\δq}\end{array}\right.---\left(1\right)$

Wherein: δ p, δ q are the trend flowing to 2 nodes on coupled impedance branch road,

$\left\{\begin{array}{c}\mathrm{\δp}=u_1{u}_2[{(-1)}^i{g}_{12}\cos ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)+b_{12}\sin ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)]-{(-1)}^i{g}_{12}{u_i}^2\\ \mathrm{\δq}=u_1{u}_2[g_{12}\sin ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)-{(-1)}^i{b}_{12}\cos ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)]+{(-1)}^i{b}_{12}{u_i}^2\end{array}\right.---\left(2\right)$

6 unknown parameter: e are had by the equation group that formula (1), (2) form_i、δ_i、g_i、b_i、g₁₂、b₁₂.

The solution procedure of external system equivalent parameters is as follows:

1) under a certain method of operation, carry out Load flow calculation, obtain equivalent border power conserving voltage u_i1、θ_i1With trend p_i1、 q_i1.

2), internally near close equivalent point in grid, it is slightly increased or reduces the low-voltage-grade load of this point, Carry out Load flow calculation and obtain the new voltage of boundary node and trend, i.e. u_i2、θ_i2、p_i2、q_i2.In the same manner, obtain another group of u_i3、θ_i3、 p_i3、q_i3.

3) three groups obtained in step 1,2 data are substituted in equation (1) and (2), obtain with regard to unknown number e_i、δ_i、g_i、 b_i、g₁₂、b₁₂Equation.

4) carry out numerical solution, the e of equivalent point can be obtained_i、δ_i、g_i、b_i、g₁₂, and b₁₂Value.

S103: build simulation model.

Simulation model is built according to direct parameter and indirect parameter, this simulation model is that voltage source series impedance form is inside Portion's grid is powered, as shown in Figure 3.

After equivalence, external system network parameter is:

$\left\{\begin{array}{c}{\stackrel{\·}{e}}_i=e_i\∠{\mathrm{\δ}}_i\\ {\stackrel{\·}{u}}_i=u_i\∠{\mathrm{\θ}}_i\\ y_i=\frac{1}{z_i}=g_i+{\mathrm{jb}}_i\end{array}\right.(i=\mathrm{1,2})$

$y_{12}=\frac{1}{z_{12}}=g_{12}+{\mathrm{jb}}_{12}$

In formula:Refer to the equivalent voltage source phasor being connected with boundary node i；

e_iRefer to voltage source phasorAmplitude；

δ_iRefer to voltage source phasorPhase place；

Refer to the voltage phasor of boundary node i；

u_iRefer to voltage phasorAmplitude；

θ_iRefer to voltage phasorPhase place；

y_i(or z_i) refer to the Equivalent admittance (or impedance) that is connected with node i；

g_iRefer to the equivalet conductance being connected with node i；

b_iRefer to the equivalent susceptance being connected with node i；

y₁₂(or z₁₂) refer to the coupling admittance (or impedance) economizing on electricity between 2 in border economize on electricity 1 and border；

g₁₂Refer to border economize on electricity 1 and border economize on electricity 2 between couple conductance；

b₁₂Refer to border economize on electricity 1 and border economize on electricity 2 between couple susceptance.

From technique scheme as can be seen that power system disclosed in the present embodiment based on boundary node real measured data Two-port Equivalent Network method, obtains direct parameter first, then makes a thorough investigation of direct parameter and calculates indirect parameter, and according to directly ginseng Number and indirect parameter build simulation model, and this simulation model is that voltage source series impedance form internally power by grid.With Quickly internal grid can be emulated such that it is able to be accelerated simulation process based on this, be improve operating efficiency.

Embodiment two

Fig. 4 is a kind of structure of the two-port Equivalent Network device based on boundary node real measured data disclosed in the present embodiment Figure.

As shown in figure 4, emulation mode disclosed in the embodiment of the present application includes acquiring unit 10, computing unit 20 and simulation list Unit 30, wherein computing unit 20 is connected with acquiring unit 10, analogue unit 30 respectively.

Acquiring unit 10 is used for obtaining direct parameter.

Acquiring unit 10 obtains the direct parameter of the boundary node of power system, and direct parameter includes the node of boundary node The active power of voltage phasor and interconnection and reactive power.

Computing unit 20 is used for calculating indirect parameter.

According to the direct parameter obtaining, the such as node voltage phasor of boundary node and the active power of interconnection and idle work( Rate, direct parameter is substituted into default equation group, is calculated indirect parameter.Default equation group is node power flow equation, Connect the equivalent parameters that parameter is external system model, including voltage source phasor, equivalent self-impedance and coupled impedance.

Theoretical according to network topology, the node trend writing boundary node i is arranged to equivalent external system network, boundary system Equation.

$\left\{\begin{array}{c}{p}_i=e_i{u}_i[g_i\cos ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)+b_i\sin ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)]-g_i{u_i}^2+{(-1)}^i\mathrm{\δp}\\ q_i=e_i{u}_i[g_i\sin ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)-b_i\cos ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)]+b_i{u_i}^2+{(-1)}^i\mathrm{\δq}\end{array}\right.---\left(1\right)$

Wherein: δ p, δ q are the trend flowing to 2 nodes on coupled impedance branch road,

$\left\{\begin{array}{c}\mathrm{\δp}=u_1{u}_2[{(-1)}^i{g}_{12}\cos ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)+b_{12}\sin ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)]-{(-1)}^i{g}_{12}{u_i}^2\\ \mathrm{\δq}=u_1{u}_2[g_{12}\sin ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)-{(-1)}^i{b}_{12}\cos ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)]+{(-1)}^i{b}_{12}{u_i}^2\end{array}\right.---\left(2\right)$

6 unknown parameter: e are had by the equation group that formula (1), (2) form_i、δ_i、g_i、b_i、g₁₂、b₁₂.

The solution procedure of external system equivalent parameters is as follows:

1) under a certain method of operation, carry out Load flow calculation, obtain equivalent border power conserving voltage u_i1、θ_i1With trend p_i1、 q_i1.

2), internally near close equivalent point in grid, it is slightly increased or reduces the low-voltage-grade load of this point, Carry out Load flow calculation and obtain the new voltage of boundary node and trend, i.e. u_i2、θ_i2、p_i2、q_i2.In the same manner, obtain another group of u_i3、θ_i3、 p_i3、q_i3.

3) three groups obtained in step 1,2 data are substituted in equation (1) and (2), obtain with regard to unknown number e_i、δ_i、g_i、 b_i、g₁₂、b₁₂Equation.

4) carry out numerical solution, the e of equivalent point can be obtained_i、δ_i、g_i、b_i、g₁₂, and b₁₂Value.

Analogue unit 30 is used for building simulation model.

Simulation model is built according to direct parameter and indirect parameter, and internally grid with voltage source series impedance shape Formula is powered.

After equivalence, external system network parameter is:

$\left\{\begin{array}{c}{\stackrel{\·}{e}}_i=e_i\∠{\mathrm{\δ}}_i\\ {\stackrel{\·}{u}}_i=u_i\∠{\mathrm{\θ}}_i\\ y_i=\frac{1}{z_i}=g_i+{\mathrm{jb}}_i\end{array}\right.(i=\mathrm{1,2})$

$y_{12}=\frac{1}{z_{12}}=g_{12}+{\mathrm{jb}}_{12}$

In formula:Refer to the equivalent voltage source phasor being connected with boundary node i；

e_iRefer to voltage source phasorAmplitude；

δ_iRefer to voltage source phasorPhase place；

Refer to the voltage phasor of boundary node i；

u_iRefer to voltage phasorAmplitude；

θ_iRefer to voltage phasorPhase place；

y_i(or z_i) refer to the Equivalent admittance (or impedance) that is connected with node i；

g_iRefer to the equivalet conductance being connected with node i；

b_iRefer to the equivalent susceptance being connected with node i；

y₁₂(or z₁₂) refer to the coupling admittance (or impedance) economizing on electricity between 2 in border economize on electricity 1 and border；

g₁₂Refer to border economize on electricity 1 and border economize on electricity 2 between couple conductance；

b₁₂Refer to border economize on electricity 1 and border economize on electricity 2 between couple susceptance.

From technique scheme as can be seen that the simulator of power system disclosed in the present embodiment obtains direct ginseng first Number, then makes a thorough investigation of direct parameter and calculates indirect parameter, and build simulation model, this emulation mould according to direct parameter and indirect parameter Type is that voltage source series impedance form internally power by grid.Quickly internal grid can be carried out based on this Emulation, such that it is able to accelerate simulation process, improves operating efficiency.

Below taking the power system master pattern of ieee14 node as a example, the topological structure of its system as shown in figure 5, Ieee14 node system can be divided into 3 parts it may be assumed that built-in system network, external system network and boundary node.Node 4 and node 5 be boundary node, reservations node be 1～5 node, remainder need simplify equivalence.Application present invention research etc. Value method simplifies equivalent, member-retaining portion static system Characteristic Contrast such as table 1, table 2, table 3 before and after equivalence to ieee14 node system Shown.

When system suffers from large disturbances, before and after equivalence, the transient characterisitics of system are to such as shown in Fig. 6, Fig. 7, Fig. 8 and Fig. 9.

Result shows, with the equivalence method of the two-port network based on boundary node real measured data to ieee14 node system External system network carry out simplifying equivalent, ensure that the short circuit current of system member-retaining portion before and after equivalence is basically identical；From System suffers from line voltage distribution under large disturbances fault, active power and reactive power contrast to can be seen that each mother of system before and after equivalence Line voltage level, trend distribution are basically identical, and maximum deviation comes across transient process, and system recovers the trend basic one after stablizing Cause.It is therefore contemplated that the system simplifying after equivalence maintains the transient characterisitics of original system substantially.

Boundary node short-circuit current level contrast before and after table 1 equivalence

Member-retaining portion node voltage contrast before and after table 2 equivalence

Member-retaining portion trend profiles versus before and after table 3 equivalence

Last in addition it is also necessary to explanation, herein, such as first and second or the like relational terms be used merely to by One entity or operation are made a distinction with another entity or operation, and not necessarily require or imply these entities or operation Between there is any this actual relation or order.And, term " inclusion ", "comprising" or its any other variant meaning Covering comprising of nonexcludability, so that including a series of process of key elements, method, article or equipment not only include that A little key elements, but also include other key elements being not expressly set out, or also include for this process, method, article or The intrinsic key element of equipment.In the absence of more restrictions, the key element being limited by sentence "including a ...", does not arrange Remove and also there is other identical element in the process including described key element, method, article or equipment.

In this specification, each embodiment is described by the way of going forward one by one, and what each embodiment stressed is and other The difference of embodiment, between each embodiment identical similar portion mutually referring to.

Described above to the disclosed embodiments, makes professional and technical personnel in the field be capable of or uses the application. Multiple modifications to these embodiments will be apparent from for those skilled in the art, as defined herein General Principle can be realized in the case of without departing from spirit herein or scope in other embodiments.Therefore, the application It is not intended to be limited to the embodiments shown herein, and be to fit to and principles disclosed herein and features of novelty phase one The scope the widest causing.

Claims (2)

1. a kind of two-port Equivalent Network method based on boundary node real measured data is it is characterised in that include:

Obtain the direct parameter of the boundary node of external system network；

Described direct parameter is substituted into default equation group, is calculated indirect parameter；

Simulation model is built according to described direct parameter and described indirect parameter；

Wherein, described equation group is node power flow equation group, comprising:

$\left\{\begin{array}{c}{p}_i=e_i{u}_i\[g_i\cos ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)+b_i\sin ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)\]-g_i{u_i}^2+{(-1)}^i\mathrm{\δ}p\\ q_i=e_i{u}_i\[g_i\sin ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)-b_i\cos ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)\]+b_i{u_i}^2+{(-1)}^i\mathrm{\δ}q\end{array}\right.---\left(1\right)$

Wherein: " i " represents boundary node, value is 1 or 2, " p_i" be boundary node i active power, " e_i" be and boundary node The connected amplitude of equivalent voltage source phasor of i, " u_i" be boundary node i the amplitude of voltage phasor, " θ_i" it is boundary node i The phase place of voltage phasor, " δ_i" it is equivalent voltage source the phasor, " b being connected with boundary node i_i" be connected with boundary node i etc. Value susceptance, " g_i" it is the equivalet conductance, " q being connected with boundary node i_i" be boundary node i reactive power；

△ p, △ q are the trend flowing to 2 nodes on coupled impedance branch road,

$\left\{\begin{array}{c}\mathrm{\δ}p=u_1{u}_2\[{(-1)}^i{g}_{12}\cos ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)+b_{12}\sin ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)\]-{(-1)}^i{g}_{12}{u_i}^2\\ \mathrm{\δ}q=u_1{u}_2\[g_{12}\sin ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)-{(-1)}^i{b}_{12}\cos ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)\]+{(-1)}^i{b}_{12}{u_i}^2\end{array}\right.---\left(2\right)$

Wherein, " i " represents boundary node, and value is 1 or 2, " u₁" be boundary node 1 the amplitude of voltage phasor, " u₂" it is border The amplitude of the voltage phasor of node 2, " g₁₂" it is to couple conductance, " θ between boundary node 1 and boundary node 2₂" it is boundary node The phase place of 2 voltage phasor, " θ₁" be boundary node 1 the phase place of voltage phasor, " b₁₂" it is boundary node 1 and boundary node 2 Between coupling susceptance, " u_i" be boundary node i voltage phasor amplitude；

The described indirect parameter that is calculated includes:

Under a certain method of operation, carry out Load flow calculation, obtain equivalent border power conserving voltage u_i1、θ_i1With trend p_i1、q_i1；

Internally in grid near equivalent point, it is slightly increased or reduces the low-voltage-grade load of this point, carry out tide Stream calculation obtains the new voltage of boundary node and trend, i.e. u_i2、θ_i2、p_i2、q_i2；

In the same manner, obtain another group of u_i3、θ_i3、p_i3、q_i3；

Obtain three groups of data are substituted in equation (1) and (2), obtains with regard to unknown number e_i、δ_i、g_i、b_i、g₁₂、b₁₂Equation；

Numerical solution, you can obtain the e of equivalent point_i、δ_i、g_i、b_i、g₁₂, and b₁₂Value.

2. a kind of two-port Equivalent Network device based on boundary node real measured data is it is characterised in that include:

Measuring unit, for obtaining the direct parameter of the boundary node of external system network；

Computing unit, for described direct parameter is substituted into default equation group, is calculated indirect parameter；

Analogue unit, for building simulation model according to described direct parameter and described indirect parameter, and with the source-series resistance of voltage Anti- form internally power by grid；

Wherein, described equation group is node power flow equation group, comprising:

$\left\{\begin{array}{c}{p}_i=e_i{u}_i\[g_i\cos ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)+b_i\sin ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)\]-g_i{u_i}^2+{(-1)}^i\mathrm{\δ}p\\ q_i=e_i{u}_i\[g_i\sin ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)-b_i\cos ({\mathrm{\θ}}_i-{\mathrm{\δ}}_i)\]+b_i{u_i}^2+{(-1)}^i\mathrm{\δ}q\end{array}\right.---\left(1\right)$

Wherein: " i " represents boundary node, value is 1 or 2, " p_i" be boundary node i active power, " e_i" be and boundary node The connected amplitude of equivalent voltage source phasor of i, " u_i" be boundary node i the amplitude of voltage phasor, " θ_i" it is boundary node i The phase place of voltage phasor, " δ_i" it is equivalent voltage source the phasor, " b being connected with boundary node i_i" be connected with boundary node i etc. Value susceptance, " g_i" it is the equivalet conductance, " q being connected with boundary node i_i" be boundary node i reactive power；△ p, △ q are coupling The trend flowing to 2 nodes on impedance branch,

$\left\{\begin{array}{c}\mathrm{\δ}p=u_1{u}_2\[{(-1)}^i{g}_{12}\cos ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)+b_{12}\sin ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)\]-{(-1)}^i{g}_{12}{u_i}^2\\ \mathrm{\δ}q=u_1{u}_2\[g_{12}\sin ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)-{(-1)}^i{b}_{12}\cos ({\mathrm{\θ}}_2-{\mathrm{\θ}}_1)\]+{(-1)}^i{b}_{12}{u_i}^2\end{array}\right.---\left(2\right)$

Wherein, " i " represents boundary node, and value is 1 or 2, " u₁" be boundary node 1 the amplitude of voltage phasor, " u₂" it is border The amplitude of the voltage phasor of node 2, " g₁₂" it is to couple conductance, " θ between boundary node 1 and boundary node 2₂" it is boundary node The phase place of 2 voltage phasor, " θ₁" be boundary node 1 the phase place of voltage phasor, " b₁₂" it is boundary node 1 and boundary node 2 Between coupling susceptance, " u_i" be boundary node i voltage phasor amplitude；

The described indirect parameter that is calculated includes:

Under a certain method of operation, carry out Load flow calculation, obtain equivalent border power conserving voltage u_i1、θ_i1With trend p_i1、q_i1；

Internally in grid near equivalent point, it is slightly increased or reduces the low-voltage-grade load of this point, carry out tide Stream calculation obtains the new voltage of boundary node and trend, i.e. u_i2、θ_i2、p_i2、q_i2；

In the same manner, obtain another group of u_i3、θ_i3、p_i3、q_i3；

Obtain three groups of data are substituted in equation (1) and (2), obtains with regard to unknown number e_i、δ_i、g_i、b_i、g₁₂、b₁₂Equation；

Numerical solution, you can obtain the e of equivalent point_i、δ_i、g_i、b_i、g₁₂, and b₁₂Value.